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TABLE OF CONTENTS
1.0
INTRODUCTION
4
1.1
Background
4
1.2
Objectives
5
1.3
Definition Of Terms
5
1.4
Abbreviations
5
1.5
Design Life
7
1.6
Reservoir & Well Data
7
1.7
Produced Water
8
1.8
CO2 and H2S Content
9
1.9
Mercury
9
1.10
Sand
9
2.0
CORROSION MECHANISM
9
2.1
Internal Corrosion
9
2.2
External Degradation
14
3.0
MATERIAL MINIMUM TEMPERATURE LIMITATION
14
4.0
MATERIAL SELECTION FOR THIEN UNG FIXED PLATFORM FACILITIES15
4.1
Production System
15
4.2
Potable Water and Wash Water System
17
4.3
Seawater System
17
4.4
Instrument and Utility Air System
17
4.5
Waste Heat Recovery and Hot Oil System
18
4.6
Sewage System
18
4.7
Nitrogen System
18
4.8
Fuel Gas System
18
4.9
HP Flare System
18
4.10
LP Flare System
19
4.11
CPP Closed and Open Drain Systems
19
4.12
Aviation Fuel System
20
4.13
Diesel Fuel System
20
4.14
Methanol Injection System
20
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4.15
Corrosion Inhibitor Injection System
20
5.0
CHEMICAL INJECTION
21
6.0
CORROSION MONITORING
22
7.0
REFERENCES
23
8.0
APPENDIX 1 – CO2 CORROSION ASSESSMENT RESULT TABLE
24
9.0
APPENDIX 2 – MATERIAL SELECTION TABLE
28
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INTRODUCTION
1.1
Background
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The Thien Ung field is located in the middle part of Block 04.3 in the Nam Con Son Basin,
offshore the Socialist Republic of Vietnam, approximately 15 km of Dai Hung field and
approximately 270 km southeast of Vung Tau. The block 04.3 covers an area of approximately
2600 km2. The Thien Ung field is including its 2 structural part. Thien Ung structure discovery
was made in 2004 with the 04.3-TU-1X well. Two subsequent appraisal wells (04.3-TU-2X and
04.3-TU-3X), drilled and tested respectively, delineated the field.
Location of Thien Ung field is shown in Figure 1.1 below.
Figure 1.1: Thien Ung Reservoir Location
A Pre-FEED study was carried out to select the most viable platform configuration. The
configuration of two separate platforms, namely Fixed Drilling Platform (FDP) and Central
Processing Platform (CPP) bridge linked were selected for FEED. Drilling will be carried out by
self contained Modular Drilling Rig located at FDP.
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Objectives
This document defines the material selection basis and corrosion protection philosophy for Thien
Ung field development. It includes the minimum recommendations for the material selection for the
Fixed Drilling Platform (FDP) and Central Processing Platform (CPP) topsides.
Materials specified in the current design at this FEED stage are acceptable but
relatively conservative. A material selection study has been done to optimize the
materials utilization. Materials recommended in Although the piping in this system is not
NACE specified due to the low design pressure, it is recommended that the vessels to be NACE
specified.
this report for certain systems are less conservative as compared to the materials in the current
design and to be considered and further study during the next phase of Detail Engineering Design.
A brief corrosion monitoring philosophy is also included.
Materials are recommended based on the intended service and operation constraints as per the
H&MB. Any changes in the operating conditions during next project stage may require review and
modification of the selected materials.
1.3
Definition Of Terms
Within this document the following definitions shall apply:
1.4
COMPANY
The party which initiates the project and ultimately pays for its
design and construction and owns the facilities. Here the
COMPANY is Vietsovpetro JV (referred to as VSP).
CONTRACTOR
The party which carries out all or part of the design, engineering,
procurement, construction and commissioning of the project.
VENDOR
The party which the order or contract of supply of the
equipment/package or services is placed.
Shall
Refers to mandatory requirement
Should
Refers to a recommendation
Abbreviations
bbl/d
Barrel per day
BLC
Bottom line corrosion
CA
Corrosion allowance
CAPEX
Capital expenses
CC
Corrosion coupon
CO2
Carbon dioxide
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CPP
Central Processing Platform
Cr
Chromium
CRA
Corrosion resistance alloy
Cru
Corrosion rate
CS
Carbon steel
CSSC
Chloride Stress Corrosion Cracking
D
Diameter
DegC
Degrees celcius
DSS
Duplex stainless steel
ERP
Electrical resistance probe
FDP
Fixed Drilling Platform
FEED
Front end engineering design
FPSO
Floating production storage and offloading
FWHP
Flowing wellhead pressure
FWHT
Flowing wellhead temperature
GRP
Glass reinforced platics
H&MB
Heat and material balance
HHP
High high pressure
HIC
Hydrogen Induced Cracking
HP
High pressure
HSE
Health, Safety and Environment
H2S
Hydrogen sulphide
KO
Knocked-out
LP
Low pressure
LTCS
Low temperature carbon steel
m/s
Meter per second
MIC
Microbiologically influenced corrosion
mm/yr
Millimetre per year
MMSCFD
Million standard cubic feet per day
MP
Medium pressure
NNF
Normally no flow
OPEX
Operation expenses
PC
Potential corrosivity
ppm
Parts per million
SDSS
Super duplex stainless steel
SC
Sampling connection
SRB
Sulfate reducing bacteria
SS
Stainless steel
SWC
Step Wise Cracking
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THPS
Tetrakis hydroxymethyl phosphonium sulphate
TLC
Top of line
TRB
Thiosulphate reducing bacteria
TSA
Thermally Sprayed Aluminum
WCR
Water condensation rate
WHP
Wellhead platform
WHSIP
Wellhead shut in pressure
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Design Life
The facilities shall be design for a service life of 25 years [1].
1.6
Reservoir & Well Data
The following key reservoir data for Thien Ung 04-3X block as given in document 5691-GEN-PRRPT-9901 shall be used to achieve the water analysis consistency.
Table 1.0: Key Reservoir Data for Thien Ung 04-3X Block [1].
Parameter
Value
Reservoir Pressure (barg)
Reservoir Temperature (°C)
257 – 504 (254 – 497 atm)
112 - 153
The full well stream compositions are based on the well working pressure of 410 barg and
temperature of 148°C [1]. The full well stream compositions that are confirmed by VSP to be used
for process design are given in the following table. The compositions are based on year six
production [1].
Table 1.1: Full Well Stream Composition (Dry Basis) [1].
Component
Full Well Stream (mole%)
H2S
0.000
CO2
9.597
N2
0.383
C1
70.345
C2
7.823
C3
4.553
iC4
1.120
nC4
1.326
iC5
0.545
nC5
0.382
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Component
Full Well Stream (mole%)
Pseudo C6
Pseudo C7
Pseudo C8
Pseudo C9
Pseudo C10
Pseudo C11
Pseudo C12
Pseudo C13
Pseudo C14
Pseudo C15
Pseudo C16
Pseudo C17
Pseudo C18
Pseudo C19
Pseudo C20+
Total
0.777
0.838
0.580
0.296
0.243
0.146
0.127
0.104
0.078
0.065
0.043
0.022
0.019
0.018
0.570
100
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Produced Water
Water analysis from Thien Ung 04-3X block field given by VSP is summarized in the following
table:
Table 1.2: Water Analysis Constituents (taken from excel spreadsheet
Water_Analysis_Bang_1.6.3)
Cations
Na+
K+
Ca++
Mg++
Fe++
Sr++
Ba++
Anions
ClHCO3CO3-AcSO4--
meq/L
489.91
2307
1525
137
15.25
meq/L
626.76
769
0
13.24
mg/L
11268
2307
1525
137
15.25
mg/L
22250
769
0
635.4
As tabulated in the table above, no acetic acid content is reported. For corrosion assessment with
Corplus software, recommended default acetic acid value shall be used is 59mg/L.
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CO2 and H2S Content
CO2 in vapor phase composition value of each stream given by Process group shall be used
for corrosion assessment by Corplus.
There is no significant H 2S detected in any of the well tests. However for design purpose, the
design maximum H 2S for combined production will be taken as 20 ppmv [1].
1.9
Mercury
No significant mercury content was detected in any of the well test to date [1].
1.10
Sand
According to Process and Utility Design Basis, 5691-GEN-PR-RPT-9901, studies have indicated
a risk for low levels of solids production from wells during later years of field life. The sand control
philosophy will be to manage sand down-hole through the use of gravel packs or screens. There
is a small risk that sand may accumulate in the production separators during later years of field
life. These vessels should therefore be equipped with appropriate internal sand flushing from the
vessels during later years of field life. Peak predicted sand loading is less than 130 litres/MMscm
(16 -17 lb/MMscf) [1].
As per VSP clarification, influence of sand on abrasive damage is low where carrying out of sand
from gas wells is always low especially if sand traps use in wells [7].
2.0
CORROSION MECHANISM
2.1
Internal Corrosion
The most likely degradation mechanisms that can cause internal damage to hydrocarbon
systems are as follow:
CO2 Corrosion;
H2S Cracking;
Microbiologically Influenced Corrosion (MIC); and
Galvanic Corrosion.
Erosion Corrosion
2.1.1
CO2 Corrosion
CO2 corrosion constitutes the major cause of metal loss of carbon steel components of which
surface exposed to water. Any water in contact with vapor phase CO 2 will dissolve the CO2 and
form weak carbonic acid; which may lower the pH and consequently promote general corrosion
and/ pitting corrosion. Although it is a weak acid, carbonic acid is highly corrosive because the
cathodic part of the corrosion reaction does not need H+ as with normal acid corrosion but
instead involves direct reduction of undissociated acid.
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Parameters affecting CO2 corrosion include:
Water chemistry, organics acids, pH, water wetting, hydrocarbon characteristics and
phase ratios;
CO2 and H2S content (and possible oxygen contaminants);
Temperature and pressure;
Steel surface including corrosion film morphology;
Fluid dynamics; and
Steel chemistry.
Water Wetting
Water in the hydrocarbon mixture can be entrapped completely in the oil emulsion or it can be
present as a separate water phase. In order for corrosion to occur; water must wet the steel
surface. The presence of water phase depends on:
Water cut;
Flow condition (velocity, flow regime, surface condition); and
Light or heavy hydrocarbon (water separation is easier in light hydrocarbon).
Effect Of Condensation
During hydrocarbon gas transportation, condensation of water vapor may occur on the internal
pipe wall due to some cooling effects of the fluid. If water is condensing, the water will be
saturated with the acid gas CO2 and acetic acid with pH typically <4.
High condensation rate could subsequently lead to high corrosion rates due to low pH of purely
condensing water. If the condensation rate is slow, the water film will be saturated with corrosion
product leading to a high pH and the formation of possibly protective iron carbonate film.
CO2 Corrosion Model
CO2 corrosion assessment of this project was performed using Corplus V21 Corrosion Evaluation
Tool. Refer Corplus evaluation result in Appendix 1.
Corplus is a CO2 corrosion prediction tool for Carbon steel materials. It also gives erosion
corrosion conditions and sour services conditions based on MR0175/ISO15156 severity diagram.
This model was developed by the Total Company based on the previous Cormed model from Elf
and Lipucor model from Total and verified by laboratory testing conducted in a Norwegian
Institute IFE under a JIP project (Joint Industrial Programs) where other operators were involved
including Statoil, Norsk Hydro, Shell etc.
The main characteristics of the two models at the origin were the data base which was extracted
from many feedback experiences of fields of production.
Corplus is mainly a pH and corrosion prediction tool for oil and gas production facilities. It
contains three main prediction modules:
pH calculations
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corrosion prediction, erosion-corrosion in sweet conditions
sour service prediction
The Corplus model corrosion evaluation is based on past experiences and wide field data base.
It combines/improves capabilities of previous models from Cormed (ELF), Lipucor (Total) and
others like KFD2 JIP project.
The CO2 corrosiveness which is the most accurate predictive parameter provided Corplus can be
defined through different categories as indicated in the table below:
Table 1.3: Classification of CO2 Corrosiveness according to CORPLUS
CO2
Corrosiveness/Corrosion
likelihood
Typical corrosion rate
-> CO2 corrosiveness
Approximate lifetime vs design life (assuming no
preventive action) * ->CO2 Corrosion likelihood
Practical
failure
likelihood
Very low
< 0.1 mm/yr
System will last much longer than required with no
failures, without any preventive action
None
Low
0.1 – 0.3 mm/yr
System should reach its design life without a
failure with available corrosion allowances, not
requiring any complementary preventive action
Negligible
Medium
0.3 to 1 mm/yr
System should reach 50% of its design life before
a failure occurs, if no preventive action is
undertaken
Likely but
delayed
High
1 to 3 mm/yr
A failure will occur after 25% of its design life, if no
preventive action is undertaken
Very likely
within a few
years
Very high
> 3- 5 mm/yr
The system will not even resist ¼ of its design life,
if no preventive action is undertaken
Certain and
soon
* : Indicative only, since limits are dependent on wall thickness and design life. 10- 15 mm and
20- 25 yrs considered as default values.
Corrosion rate: This quantitative parameter is aimed at characterizing the corrosion rate of the
whole fluid (including oil and gas) to corrode the steel surface within the given calculation
conditions. It is determined from quantitative criteria considering pH, PC, corrective factors for
temperature, glycol, oil/ water wetting. On the other hand, no complementary qualitative
parameters referring to pitting tendencies and protectivity by corrosion products are considered,
as for the complete CO2 corrosiveness.
CO2 corrosiveness: It is the actual capacity of the water, if any, to corrode the steel surface
within the given calculating conditions. When compared to the quantitative corrosion rate
calculation described here above, this parameter:
Include additional qualitative criteria determined from a detailed review of field
experience, about practical pitting tendency or protectivity by corrosion products
Does not include any possible beneficial effect of oil wetting, so it is only related to the
corrosiveness of the produced water
Is provided in qualitative severity categories as indicated in the table
The lower of these 2 parameters must be used.
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Microbiologically Induced Corrosion (MIC)
Microbiologically Induced Corrosion (MIC) is a mode of corrosion incorporating microbes like SRB
(Sulphate Reducing Bacteria) or TRB (Thiosulphate Reducing Bacteria) that react and form H2S
which cause corrosion. The most likely sources are from drilling campaigns, well service
activities, precommissioning or hydrotest activities, sump systems, vessel cleaning or
maintenance operations. The MIC normally occurs under deposits, in low velocity flow or
stagnant water. Activities like hydrotesting, vessel cleaning or any other activities which allow
ingress of water into the equipments or piping must only use treated (sea) water.
MIC could be monitored by doing sampling, however this method will assess bacteria of mostly
the mobile (planktonic) ones. It is recommended to do sampling at the inlet of the pipelines and at
the downstream of the open caisson and closed drain drum. It is crucial to monitor the sessile
(surface adhering) bacteria as it will adhere to the surface and has chances to reduce the sulphur
to acid and eventually corrodes the surface. One of the monitoring methods is by placing bioprobes.
If bacteria are detected then biocides should be used to mitigate the bacteria growth. Common
biocides used are glutaraldehyde, quaternary ammonium or THPS. For treatment of vessels,
injection of certain amount of biocide into the vessel is necessary after each transfer of effluent to
the production facilities. When the vessel is full of liquid, at least 200ppm concentration of the
active product is required. Refer to the options below for the bacteria control of pipelines which
has been proven to be sufficient:
Option 1
Weekly pigging, inject Biocide for 2 hours, 3 times per week.
Option 2
8 hours of continuous injection on weekly basis immediately after pig launching.
Normal Operation: - 500ppm
Upset Condition: - 1000ppm
Note: Injection rate given above is a practice of an operator in Sarawak oil and gas field which
may be a basis for Thien Ung Fixed Platform FEED. The injection rates have been proven to be
sufficient for Sarawak field but the concentration will vary according to projects. Injection rates for
Thien Ung will be confirmed prior to vendor’s discussion. The use of any biocides, oxygen
scavengers or combination chemicals should be qualified to assess the suitability prior to use.
2.1.3
Sand Erosion
For cases where sand is expected, excessive sand production may cause sand erosion
especially at components that experience sudden directional change (ex. elbow) or flow
restriction (ex choke and valve). Important factors that determine sand erosion sand erosion rate
including sand production rate, fluid properties (velocity, viscosity, and density) and sand
characteristics (size, hardness, shape).
The sand control philosophy of Thien Ung platforms will be to manage sand down-hole through
the use of gravel packs or screens. Due to the risk that sand may accumulate in the production
separators during later years of field life, these vessels should therefore be equipped with
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appropriate internal sand flushing and nozzles to enable sand handling and flushing from the
vessels during later years of field life.
As per VSP clarification, influence of sand on abrasive damage is low where carrying out of sand
from gas wells is always low especially if sand traps use in wells [7].
Other philosophy being implemented by other projects is to have a non-intrusive sand detector on
each flowline. If sand is detected, production from the well will be cut back or the well will be shutin manually or remotely and worked over to eliminate sand production.
It is recommended that the risk of erosion should be undertaken at susceptible areas e.g bend,
choke valves.
2.1.4
Dissimilar Material
There is a risk of galvanic corrosion when connecting CRA and carbon steel pipes with existence
of corrosive free electrolyte (ex: water) flowing through the joints.
In order to minimize galvanic corrosion at these joints on wet service process piping, the following
rules shall be applied:
1) A flange connection shall be applied;
2) The whole CS flange surface including the ring groove or gasket surface shall be cladded with
suitable CRA like SS316L;
3) CRA ring joint or gasket shall be used between CRA and the cladded CS side; and
4) The connection to be located as far as possible on a vertical position to avoid trapped water at
the joints.
This solution applies to wet piping with corrosive fluid and it is not needed for dry gas, oil piping or
non corrosive service.
2.1.5
Internal Coating of Vessels/ Tanks
In order to ensure an internal corrosion protection, carbon steel vessels or tanks shall be
internally coated when continuous water phase can be present. This is particularly the case of
separators, drain sump tanks, water tanks and crude oil/ condensate storage tanks. Depending
on the working condition and also the size of the tank, the coating specification will be finalized on
case by case basis whether to be coated fully or only at the bottom part where water
accumulation may occur. It is recommended that the coating is associated with cathodic
protection provided by sacrificial anodes as precaution in case of any imperfection of the applied
coating. For the internal coating applied with GRP, in the range of 1 to 2mm thickness, sacrificial
anodes can be avoided as far as the quality of the applied coating is high. Common types of
sacrificial anodes are Zn and Al anode depending on the service condition.
Remarks:
The anode consumption will be verified during the internal inspection. The sacrificial anodes will
only be consumed if there is any imperfection of the applied protective coating.
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2.2
External Degradation
2.2.1
External Chloride Stress Corrosion Cracking (CSCC)
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CSCC is a failure mode caused by the combined effect of tensile stress and corrosive
environment (presence of chloride ion, oxygen and high temperature). Austenitic stainless steel is
susceptible to external CSCC at temperature above 60°C while duplex stainless steel (DSS)
above 100°C. Austenitic stainless steel piping and equipment shall be externally painted if the
operating temperature is higher than 60°C. For DSS, painting shall be applied if operating
temperature higher than 100°C. Painting to be applied shall be qualified to assess the suitability
prior to use. The minimum acceptable austenitic SS is type 316/316L. The 316 materials exposed
to marine environment, shall have a minimum Mo content of 2.5%. This concerns mainly the
piping and tubing materials. For tubing connected to the main process lines & vessels that
warmer than 60°C, and piping of diameter less than 2”, the stainless steel material shall be
SS904L or 6Mo and no painting is required.
2.2.2
Piping Support
The piping supports shall be designed to avoid possible crevice corrosion of stainless steel at the
support locations, due to aqueous chloride environment. Direct supporting of non-painted SS
piping on either CS supports or even a plastic or elastomeric shoe is not recommended because
of high risk of crevice corrosion. Dedicated supporting systems must be applied on SS piping.
However, according to VSP experience stainless steel is not required for supporting of pipes,
carbon steel with plastic cover for prevention electrochemical and slot-hole corrosion is
admissible [7].
The recommendation is to apply local glass flake coating on the SS pipes (1mm thick) at the level
of the supports. Another system could consist on stratified shell composed of laminated epoxy
resin reinforced with fiber glass and glued to the pipe and finally, an elastomer sheet will be
placed between the SS pipe and the support.
3.0
MATERIAL MINIMUM TEMPERATURE LIMITATION
The material selection must take into account the minimum operating temperature and that
predicted during blowdown to avoid brittle fracture. Minimum service temperatures of various
materials are given as follow:
Metal
Carbon Steel (Note 1)
LTCS
Austenitic Stainless Steel
(i.e SS316, SS321…)
Duplex Stainless Steel
22% Cr
25% Cr
Nickel Base Alloys
Minimum Design
Temperature (degC)
0
-46
-105
-196
Impact Tested
-50
-50
-196
Yes
Yes
No
No
Yes
No
Yes
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Note 1: Carbon steel may be used in piping systems with a minimum design temperature down to
-29degC if the nominal wall thickness is less than 12.7mm, or as specified in ASME B31.3. For
lower design temperatures down to -46degC, impact testing shall be performed.
4.0
MATERIAL SELECTION FOR THIEN UNG FIXED PLATFORM FACILITIES
The overall approach to material selection for piping and equipments was initially to evaluate the
internal corrosivity of the fluids with respect to utilization of carbon steel. Corrosion resistance
alloys (CRA) or stainless steels shall be recommended for the cases where carbon steel with
corrosion allowance and corrosion inhibitor are still not sufficient to withstand the corrosion
throughout the design life. In cases where SS316L material being used at above 60°C and DSS
at above 100°C, painting shall be applied and painting shall be qualified to assess the suitability
to be used at certain design temperature.
Material recommendation is based on non-insulated piping system basis. If any piping to be
insulated, materials recommendation to be further evaluated during detail design engineering as
the insulation may have implications on the material selection.
4.1
NACE Requirements for Sour Services
The requirements outlined in the NACE MR0175/ISO 15156 shall be followed if the particular
streams are categorized in “Sour Service”. Generally, NACE requirement involves the control of
chemical composition, heat treatment, mechanical properties, hardness, environmental and
materials limits. The following covers some of the important requirements for the carbon steel &
low alloys steels and CRA according to NACE MR0175/ISO 15156.
Materials
CS and LTCS
SS316L
DSS
Additional Requirement for NACE as per NACE MR0175/ISO 15156
1) Carbon Equivalent, CE = 0.43 MAX
2) Hardness = 250HV
3) HIC/SWC TM0284 testing plate (qualification)
1) All components to be solution annealed and water quenched.
2) Hardness = 28 HRC max.
1) All components to be solution annealed and water quenched.
2) Ferrite content = 35 – 65%
CRA components e.g. 316SS and DSS purchased from reputable manufacturers and
manufactured in accordance with the appropriate ASTM product standard e.g. ASTM A240, A182
etc should be automatically compliant with the requirements of NACE MR0175 though this should
be confirmed prior to purchase.
The additional requirements required for CS and LTCS seamless and forged components to
comply with NACE MR0175, i.e. C.E and hardness limit if purchased from reputable
manufacturers and manufactured in accordance with the appropriate ASTM product standard
should be compliant with requirements of NACE MR0175, though this should be confirmed prior
to purchase.
In the case of CS and LTCS components made from plates HIC/SWC qualification testing of plate
is required in accordance TM0284. The cost of the qualification testing is dependent upon the
quantity of plate and the prevailing market conditions.
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Philosophy Report
4.2
REV. NO.
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Production System
The materials selection for the production system is based upon the production streams being
oxygen free. There is a proposal to route fluids from the LP flare KO drum/ open drain caisson to
the production separator. This will result in the possible introduction of seawater and oxygen into
the production system. This would have major implications on the materials of construction
proposed below and therefore it is recommended that the proposal for routing to the separator
should not be adopted.
Based on the Corplus corrosion evaluation results in Appendix 1, the CO 2 corrosiveness for the
streams of FDP facilities are classified as “Very High”. “Very High” corrosiveness corresponds to
the typical corrosion rate relatively beyond 3mm/yr. These streams include the flowline upstream
and downstream the choke valve going to the test separator (Stream 1A, 1B) and to the
production cooler on CPP (Stream 2) and also streams downstream the test separator (Stream
1C - 1F). From the corrosion assessments, it is indicated that the high corrosion allowance values
is beyond CS sufficiency. Since CS with 95% efficiency inhibition is insufficient to withstand the
corrosiveness and also highly unlikely to be achieved on a production piping system, CRA
material is recommended. DSS NACE is recommended for the FDP piping streams due to the
high corrosiveness and temperature. However, CS with SS316L cladded shall be recommended
for the FDP closed drain vessel due to the low design pressure where SS316L utilization is still
within the limit as per NACE MR0175/ISO15616-3. Material recommendation for FDP and CPP
facilities are summarized in Appendix 2.
Piping in the production cooler and the production separator system (Stream 102, 103) are
recommended to be in DSS NACE material. Recommendation is made based on the
corrosiveness and also by considering the high pressure piping. Due to the high pressure,
material will require higher mechanical strength to resist the pressure and this condition could be
achieved by increasing the pipe wall thickness. DSS has a higher mechanical strength compared
to SS316L and therefore will achieve a certain strength at a lower wall thickness as compared to
SS316L. DSS with lower wall thickness requirement will probably cost almost the same or maybe
slightly higher than SS316L with a higher wall thickness. The selection may have a slightly higher
CAPEX but the OPEX is reduced and also a higher mechanical strength and corrosion resistance
can be achieved.
The gas line downstream the production separator going to the TEG contactor (Stream 104, 109,
110) which contains non-dehydrated gas is recommended to be in DSS NACE material. Although
no free water is reported in the H&MB [2], but in reality water condensation on the pipe wall is
expected due to the high temperature difference between the internal pipe temperature and the
external temperature. For a 25 years design life facility, this condition may be a detrimental issue
in a long run and therefore DSS NACE is recommended. However, gas lines downstream the
TEG contactor (Stream 112, 128, 129, 140, 108,113, 107) are recommended to be in LTCS with
3mm CA NACE as the gas is dehydrated and no corrosion is expected.
Dehydrated gas lines in the export gas custody metering system (Stream 141, 115, 116, 117) up
to the production launcher are recommended to be in LTCS with 3mm CA NACE. As requested
by the Process Group, the H2S partial pressure shall be calculated based on the design pressure
instead of the operating pressure. The calculations show that the H 2S partial pressure for this
system is beyond the sweet service limitation of 0.003bar.
The condensate lines downstream the production separator up to the condensate dehydrator
(Stream 105, 119, 120, 121, 124) are recommended to be in DSS NACE. The corrosiveness of
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FRONT-END ENGINEERING DESIGN (FEED)
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Material Selection and Corrosion
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these lines is classified as “Very High” by Corplus. However, material selection of LTCS with
3mm CA NACE is recommended for the dehydrated condensate lines downstream the
condensate dehydrator up to the launcher (Stream 125, 134, 135, 126, 127, 142, 118). In the
condensate dehydrator, the dehydrated gas supplied from the TEG dehydration system will
absorb the moisture from the condensate producing dehydrated condensate. The moisture will be
carried to the rewetted stripping gas compression system and will be sent back to the TEG
dehydration system. The piping which carries the moisture (Stream 130, 131 133) is
recommended to be in DSS NACE as the wet vapour may reach its dew point and condensed on
the pipe wall.
LTCS with 3mm CA NACE is recommended for the whole Gas Compression System (Stream
143A/B, 136A/B, 138A/B, and 139A/B). Alternative of SS316L NACE is recommended in case if
there will be any condensation occurs due to the high temperature range between the upstream
and downstream of the gas compressor after cooler. According to the Process group, there
should not be any condensation since the gas is dehydrated.
4.3
Potable Water and Wash Water System
Piping upstream the potable water maker package which carries seawater shall be in copper
nickel material or in GRP as alternative. Potable water piping shall be SS316L while wash water
system piping shall be in CS with 3mm CA. Potable water storage tank and pressurized potable
water vessel shall be in CS with 3mm CA and internally epoxy coated or in GRP material. The
coating shall be approved by HSE due to the potable water service. As alternative, CS with
SS316L cladded or solid SS316L shall be recommended for the potable water storage tank and
the vessel. Selection of the alternative shall depend on the tank and vessel dimension. The wash
water tank shall be in CS with 3mm CA and internally epoxy coated. Potable water pumps shall
be in SS316 while wash water pumps shall be in CS. For the potable water filter, the vessel and
internals shall be in SS316L.
4.4
Seawater System
Piping for the whole seawater system shall be in Cu-Ni and GRP as alternative material.
Seawater lift caisson shall be made from CS with 3mm CA internally and externally with glass
flake epoxy coating on both internal and external sides. Additional protection shall be applied by
placing internal sacrificial anodes at the bottom part of the open drain caisson. The seawater lift
pumps shall be from Super Duplex Stainless Steel (SDSS) or Nickel Aluminum Bronze as
alternative. Seawater strainer shall be made of SDSS. VSP clarifies that pipes with internal
anticorrosive coatings, protective inserts are necessary for welded seams [7].
4.5
Instrument and Utility Air System
The instrument and utility air system shall be in SS316L stainless steel or galvanized CS as
alternative material. Cleanliness concern for instrument air system is detrimental to avoid rust
particles that may plug the gas distribution header. Instrument gas contaminated with particles
will cause defaults and may damage the equipments.
It has been clarified by VSP that SS316L stainless steel is necessary for air before its cleaning
but it is possible and preferable to apply galvanized steel pipes after air cleaning [7], [8].
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
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Wet air and instrument air receiver can be in CS with 3mm CA with epoxy internal coating and CS
with SS316L cladded or solid SS316L as alternative. Selection of CS with SS316L cladded or
solid SS316L shall depend on the dimension of the vessel. We highly recommend CS with
SS316L cladded or solid SS316L to avoid corrosion in case if the dryers do not function well
causing the presence of water vapor in the line.
4.6
Waste Heat Recovery and Hot Oil System
CS with 3mm CA is recommended for the piping of above system. The hot oil expansion vessels
and hot oil trim cooler shall be in CS with 3mm CA. Hot oil circulation pumps and the hot oil side
stream filter shall be in CS.
4.7
Sewage System
Sewage system piping shall be in GRP. The sewage water disposal caisson shall be made from
CS with 3mm CA internally and externally with glass flake epoxy coating on both internal and
external sides. Additional protection shall be applied by placing internal sacrificial anodes at the
bottom part of the caisson.
4.8
Nitrogen System
The piping for the nitrogen system shall be in CS with 3mm CA. The nitrogen receiver shall be in
CS with 3mm CA with internal coating.
4.9
Fuel Gas System
Piping for fuel gas system shall be in CS with 3mm CA NACE. For piping with lower design
temperature below 0deg°C, LTCS with 3mm CA NACE shall be required. Piping from the filter to
the turbine shall be in SS316L [8].
4.10
HP Flare System
Gases and liquid released from the HP equipment sources is routed to the HP flare KO drum via
HP flare header. Stainless steel LT is recommended for the HP flare header due to the very low
temperature. The painting system to be applied shall be qualified to assess the suitability to be
used at specific design temperature. As alternative, 6Mo is recommended for the header. HP
flare release separated from the drum is sent to the HP flare tip for disposal by combustion. The
same material as the header is recommended for this gas line going to the HP flare tip. The flare
tip shall be in SS310 for temperature exposed to oxidation/ scaling while SS316L minimum for
lower temperature zones. The material selection for the flare tip shall be confirmed with the
vendor.
Liquid separated in the HP flare KO drum is recovered to production separator by the HP flare KO
drum booster pumps and HP flare KO drum pumps. Liquid discharge outlet up to the shut down
valve (SDV) shall be stainless steel LT with painting due to the KO drum design conditions. As
alternative, 6Mo is recommended. Piping downstream the SDV to the HP flare KO drum pumps
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
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Material Selection and Corrosion
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shall be in LTCS 6mm CA with coating and regular basis inspection. As alternative, the piping is
recommended to be in DSS to ensure the uniformity of material selection with the production line.
Piping downstream the HP flare KO drum pumps going to the production separator shall be in
DSS. The pumps shall be in SS316. HP flare KO drum is recommended to be in solid SS316L
coated with TSA (thermally sprayed aluminum) externally. 6Mo is recommended as the
alternative.
The materials are recommended by assuming no oxygenated seawater will be recycled back to
the production separator. Introduction of seawater and oxygen into the production system will
have major implications on the materials of construction proposed.
Besides acting as the hold up drum for HP flare gases and liquid, the HP flare drum also
functions as process liquid drains drum. The process drains are routed to HP flare KO drum
through the continuous process drains header. LTCS 6mm CA with coating and regular basis
inspection shall be recommended as the header.
Although the piping in this system is not NACE specified due to the low design pressure, it is
recommended that the vessels to be NACE specified.
4.11
LP Flare System
The LP flare will take continuous hydrocarbon emissions and emergency release from the LP
equipment sources. The hydrocarbon release is routed to the LP flare KO drum via the LP flare
header. The header shall be in LTCS 6mm CA with coating and regular basis inspection.
Alternative shall be SS316L. LP flare gases separated from the drum are sent to LP flare tip for
disposal by combustion and the piping shall be in the same material as the header. The flare tip
shall be in SS310 for temperature exposed to oxidation or scaling while SS316L minimum for
lower temperature zones. The material selection for the flare tip shall be confirmed with the
vendor.
Liquid collected in the LP flare KO drum is recovered to HP flare KO Drum by the LP flare transfer
pumps. The piping is recommended to be in LTCS 6mm CA with coating and regular basis
inspection. Alternative shall be SS316L. The pumps shall be in CS.
LP flare KO drum is recommended to be in CS with 6mm CA with Phenolic coating shall be
recommended but the Phenolic coating shall be qualified and approved during detail engineering
stage for the intended services. The alternative shall be CS with SS316L cladded.
Although the piping in this system is not NACE specified due to the low design pressure, it is
recommended that the vessels to be NACE specified.
4.12
CPP Closed and Open Drain Systems
Closed drain system shall be designed to collect only the maintenance drains from the
pressurized process and utility systems on CPP and not designed to collect intermittent or
continuous process drains from the topsides. Liquid collected in the CPP closed drain vessel is
pumped by the closed drain vessel pumps to the HP flare KO drum and the gas is routed to the
LP flare header. The liquid piping is recommended to be in CS 6mm CA with coating and regular
basis inspection. Alternative shall be SS316L. The gas line shall be in CS with 3mm CA. The
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pumps shall be in CS with 13Cr impeller and SS316 as the alternative. The caisson shall be
made from CS with 3mm CA internally and externally with glass flake epoxy coating on both
internal and external sides. Additional protection shall be applied by placing internal sacrificial
anodes at the bottom part of the caisson. Residual hydrocarbon with traces of oxygen contained
seawater will be pumped out from the caisson and therefore the fluid will be very corrosive. CS
6mm CA with coating is recommended and the piping shall be monitored by inspection program.
Usage of CRA material without inspection is possible for this line if the design temperature to be
reduced during the detail design engineering stage. 25Cr Super Duplex shall be further evaluated
as the option. If the design temperature to be maintained, the options could be Titanium or Nickel
alloys where no painting and inspection program are required. The pump shall be in SDSS or NiAl-Br as an alternative.
Although the piping in this system is not NACE specified due to the low design pressure, it is
recommended that the vessels to be NACE specified.
Remarks:
The materials selection for the production system is based upon the production streams being
oxygen free. There is a proposal to route fluids from the open drain caisson to HP flare KO drum
and going back to the production separator. This will result in the possible introduction of
seawater and oxygen into the production system. This would have major implications on the
materials of construction proposed and therefore it is recommended that the proposal should not
be adopted.
4.13
Aviation Fuel System
SS316L is recommended for the aviation fuel system piping.
4.14
Diesel Fuel System
Diesel piping shall be in CS with 3mm CA. The raw diesel coarse filter and the diesel filter
coalescers shall be in CS with 3mm CA and SS316L internal parts. Diesel storage tank shall be in
CS with 3mm CA. CS shall be the recommendation for the diesel transfer pumps.
4.15
Methanol Injection System
Material recommended for the methanol injection system is CS with 3mm CA. Methanol storage
tank shall be in CS with 3mm CA.
4.16
Corrosion Inhibitor Injection System
Materials for corrosion inhibitors handling will be in SS316L to keep the chemicals clean.
However, based on VSP’s experience, GRP has been successfully applied for many years [7].
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
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CHEMICAL INJECTION
Chemical inhibitor injection is required to give protection to carbon steel piping. Corrosion inhibitor
availability measured by monitoring should be 95% or above. Chemical inhibitor injection is not
required for CRA piping. As for Thien Ung facilities, it has been studied that even with 95%
corrosion inhibitor availability, carbon steel with corrosion allowance is still not sufficient to
withstand the corrosiveness of this field. Therefore, CRA piping is recommended mostly and
corrosion inhibitor injection is not required for most of the piping system.
However, provision for corrosion inhibitor injection shall be provided for the pipeline. Corrosion
inhibitor shall be injected atleast 10 pipe diameters downstream the starting point of the carbon
steel pipeline. The 10(D) length is required to accommodate proper mixing of the corrosion
inhibitor with the production gas/ condensate. For this project, it is identified that the best location
for the CI injection point shall be upstream the gas/ condensate mixer.
Provision of biocide and oxygen scavenger or multipurpose chemical injection should be
considered for the HP flare KO drum since it will collect fluids from the open drain caisson. The
treatment is necessary in case if the open drain caisson collects corrosive fluids containing
oxygen and seawater where there will be a risk of MIC. In the case where bacteria exists, these
bacteria will then be propagated throughout the downstream of caisson to the HP flare KO drum
where residual hydrocarbon will be routed back to the HP flare KO drum and subsequently to the
production separator. Again it should be recognized that such a production scenario would have
major implications on the materials of construction recommended in this report.
Table 5.0 : Requirements of Chemical Treatment of Thien Ung facilities.
Chemical
Corrosion Inhibitor
Location
To be injected atleast 10(D)
downstream the pipeline inlet
to allow proper mixing between
the inhibitor and the product.
O2 Scavenger + Biocide
Provision for multifunctional
product injection at the HP
flare KO drum
Comments
For this project, it is identified
that the best location for the CI
injection point shall be
upstream the gas/ condensate
mixer.
To prevent bacteria growth.
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CORROSION MONITORING
Corrosion monitoring devices shall be installed to monitor the corrosivity, chemical treatment
efficiency and bacteria activity. Access fittings (standard 2”) should be provided for the use of
both ER probe and corrosion coupon (CC) as a minimum. Normally access fitting is located at 6
o’clock position. Corrosion monitoring devices shall be retrievable where a minimum clearance of
2m below the pipe is required for retrieving operation.
For cases where the pipeline is in carbon steel, ER probe, CC and SC to be installed at the
pipeline for monitoring. Coupon and probe shall be distant by 1m minimum. These devices shall
be located at the pipeline inlet upstream the barred tee.
Fluid coming from the HP flare KO drum will be monitored to trace any bacteria presence. Liquid
will be monitored by installing SC at the HP flare KO drum liquid outlet. Monitoring is necessary
because the liquid will be routed back to the production line.
Other monitoring devices of the facility are summarized in below table.
Table 6.0 : Recommended Locations for Corrosion Monitoring of Thien Ung Facilities.
Fluid
Produced Fluid
Monitoring Devices
SC
Produced Fluid
SC
Dehydrated Gas
SC
Gas/ Condensate
Mixture
Dehydrated
Condensate
Potable Water
CC, ER, SC
LP flare KO drum
SC
SC
SC
Monitoring Location
Liquid outlet of test
separator
Liquid outlet of
production separator
Downstream lean
TEG/ dehydrated gas
heat exchanger
Pipeline launcher and
receiver
Outlet of condensate
dehydrator
Downstream potable
water UV sterilizer
Liquid outlet of HP
flare KO drum
Comments
Monitor liquid quality
Monitor combined
produced liquid
arrived from FDP and
from HP flare KO
drum pumps
Monitor gas quality,
pH etc.
Monitor mixture
quality, pH etc.
Monitor condensate
quality, pH etc.
Monitor water quality
before distribution to
users.
Bacteria count
DOC NO.
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7.0
REFERENCES
1)
Process And Utility Design Basis, 5691-GEN-PR-RPT-9901, Rev 0.
2)
Heat and Material Balance, 5691-GEN-PR-HMB-XXXX, Rev 0.
3)
Process Flow Diagram, 5691-CPP-PR-PFD-XXXX, Rev 0.
4)
Utility Flow Diagram, 5691-CPP-PR-PFD-XXXX, Rev 0.
5)
NACE MR0175/ISO 15156-3 Petroleum and Natural gas Industries – Materials for Use in H2S
Containing Environments in Oil and Gas Production - Cracking-resistant CRAs (corrosionresistant alloys) and other Alloys, 2009
6)
GM EP COR 037 Use of Corplus v2: Technical Support, 2007
7)
VSP Technical Sheet Comment for Material Selection and Corrosion Philosophy Report Rev. A,
Sheet No: TW-GEN-PI-RPT-0005.
8)
5691-PM-MOM-0016, Progress Meeting 05-08-2011, Rev A.
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
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Page 24 of 33
APPENDIX 1 – CO2 CORROSION ASSESSMENT RESULT TABLE
P
(bar)
T
(°C)
Upstream of Choke
Valve
Downstream of
Choke Valve
Gas from Test
Separator
150
139.0
93.00
9.68
0.0021 13.46
0.0029
0.0145
Y
4.98
1.07
14.191
2.241
14.91
Very High
3
95
6.13
150
128.0
90.92
9.68
0.0021 12.39
0.0027
0.0145
Y
4.71
1.07
14.569
2.247
7.38
Very High
3
95
6.13
150
128.0
90.92
9.68
0.0021 12.39
0.0027
0.0028
N
4.71
1.07
-
0
6.46
Very High
7.09
1D
Condensate From
Test Separator
150
128.0
90.92
9.68
0.0021 12.39
0.0027
0.0028
N
4.71
0
14.569
0
1.57
Very High
3
1E
Water From Test
Separator
150
128.0
90.92
9.68
0.0021 12.39
0.0027
0.0028
N
4.71
0
-
2.247
0.23
Very High
6.85
1F
FWS From Test
Separator
150
127.0
90.73
9.68
0.0021 12.29
0.0027
0.0028
N
4.72
1.07
14.601
2.247
7.43
Very High
3
2
Production Cooler
Inlet
250
127.0
90.73
9.68
0.0021 12.29
0.0027
0.0028
N
4.72
3.66
49.935
7.685
5.69
Very High
7.06
95 11.20 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
102
Production Cooler
Outlet
250
126.0
50.00
9.74
0.0020 12.27
0.0025
0.0027
N
4.67
3.49
68.802
8.293
2.62
Very High
3.68
95
6.98 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
103
Production
Separator Inlet
400
126.0
50.00
9.74
0.0020 12.27
0.0025
0.0027
N
4.67
8.18
160.996
19.405
6.12
Very High
3.78
95
7.10 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
104
Gas from
Production
Separator
500
126.0
50.00
9.74
0.0020 12.27
0.0025
0.0027
N
4.67
8.18
0
0
3.76
Very Low
Note
95
105
Condensate From
Prod. Separator
300
126.0
50.00
9.74
0.0020 12.27
0.0025
0.0027
N
106
Water From Prod.
Separator
80
126.0
50.00
9.74
0.0020 12.27
0.0025
0.0027
N
107
Train 1 Dehydrated
Gas Header
600
124.5
52.87
9.76
0.0021 12.15
0.0026
0.0028
N
108
Lean TEG/Dehyd.
Gas HX Gas Outlet
600
124.5
52.87
9.76
0.0021 12.15
0.0026
0.0028
N
109
TEG Contactor Inlet
Scrb. Inlet Header
500
126.0
50.34
9.75
0.0020 12.29
0.0025
0.0027
N
110
TEG Contactor Inlet
500
126.0
50.34
9.75
0.0020 12.29
0.0025
0.0027
N
111
Liq. From TEG
Contactor Inlet
Scrubber
Dehydrated Gas
From TEG
Contactor
Train 1 Dehydrated
Gas Header
50
126.0
50.34
9.75
0.0020 12.29
0.0025
0.0027
N
600
125.5
51.34
9.76
0.0021 12.25
0.0026
0.0028
N
600
124.5
52.87
9.76
0.0021 12.15
0.0026
0.0028
N
Fuel Gas Tap Off
Gas Custody
Metering Inlet Hdr.
Gas Custody
Metering Outlet
Hdr. Gas to
Dehydrated
Static Mixer
Export to Subsea
P/L
Prod. Sep. Cond.
Pumps Discharge
150
600
124.5
124.5
52.87
52.87
9.76
9.76
0.0021 12.15
0.0021 12.15
0.0026
0.0026
0.0038
0.0038
Y
Y
Corplus gives "Very Low" results because of no
water content inserted but in reality there will be
water condensation due to temperature
differences. NACE is recommended for
materials uniformity in the system and to allow
souring through 25 yrs design life although the
pH2S is <0.003bar.
4.67
0
160.957
0.323
0.95
Very High
3
95
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
4.67
0
0.038
19.082
0.68
Very High
3.69
95
6.99 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
NACE is recommended for materials uniformity
CA is sufficient.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
NACE is recommended for materials uniformity
CA is sufficient.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
4.66
10.22
0
0
3.26
Very Low
Note
95
Corplus gives "Very Low" results because of no
water content inserted but in reality there will be
water condensation due to temperature
differences. NACE is recommended for
materials uniformity in the system and to allow
souring through 25 yrs design life although the
pH2S is <0.003bar.
4.66
10.22
0
0
3.26
Very Low
Note
95
Corplus gives "Very Low" results because of no
water content inserted but in reality there will be
water condensation due to temperature
differences. NACE is recommended for
materials uniformity in the system and to allow
souring through 25 yrs design life although the
pH2S is <0.003bar.
No flowrates given in the H&MB, materials will be the same as other material in the
NACE is recommended for materials uniformity
system.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
NACE is recommended for materials uniformity
CA is sufficient.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
NACE is recommended for materials uniformity
CA is sufficient.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and CS 3mm CA is sufficient.
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
600
123.5
52.54
9.76
0.0021 12.05
0.0026
0.0038
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
600
121.0
51.69
9.76
0.0021 11.81
0.0025
0.0038
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
600
120.5
51.33
9.78
0.0020 11.78
0.0024
0.0036
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
150
131.0
50.29
9.74
0.0020 12.76
0.0026
0.0028
N
4.65
0
160.747
0.322
2.65
Very High
3
95
Train 1 Cond. Filter
Outlet
150
129.0
50.35
9.74
0.0020 12.56
0.0026
0.0028
N
4.65
0
160.894
0.322
2.65
Very High
3
95
1A
1B
1C
112
113
114
115
116
117
118
119
120
CO2
H2S pCO2
(mol%) (mol%) (bar)
pH2S
pH2S
NACE
(bar)
(bar)
(Y/N)
operating design
pressure pressure
pH
Case 2C: 4th Production Year
Gas flow
Oil flow Water flow Flow
CO2
Cru
A
CA
(MMSCMD) (m3/h)
(m3/h)
velocity Corrosiveness (mm/yr) (%) (mm)
(m/s)
Pipe
Size
DN(mm)
Stream Stream Description
Notes
95 11.24 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
95
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
95 10.94 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
95
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
-
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
SERVICES FOR THIEN UNG FIXED PLATFORM
REV. NO.
Material Selection and Corrosion
Philosophy Report
Stream Stream Description
Pipe
Size
DN(mm)
P
(bar)
T
(°C)
CO2
H2S pCO2
(mol%) (mol%) (bar)
pH2S
pH2S
NACE
(bar)
(bar)
(Y/N)
operating design
pressure pressure
pH
0
Page 25 of 33
Case 2C: 4th Production Year
Gas flow
Oil flow Water flow Flow
CO2
Cru
A
CA
(MMSCMD) (m3/h)
(m3/h)
velocity Corrosiveness (mm/yr) (%) (mm)
(m/s)
Train 1 Cond.
Coalescer Outlet
150
128.0
50.35
9.74
0.0020 12.47
0.0026
0.0028
N
122
Water From Train 1
Cond. Coalescer
50
128.0
50.35
9.74
0.0020 12.47
0.0026
0.0028
N
124
Train 1 Dewatered
Cond. D/S LV
150
123.0
50.27
9.82
0.0021 12.08
0.0026
0.0029
N
125
Cond. From
Condensate
Dehydrator
Cond. Custody
Metering Outlet Hdr
Dehydrated Cond.
To Static Mixer
Stripping Gas Tap
Off
350
123.5
50.28
9.76
0.0021 12.05
0.0026
0.0038
Y
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
4.66
0
0
0.287
0.04
Very High
3.66
95
6.95 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
4.67
0.01
24075
0.034
2.62
Very High
3
95
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
200
126.5
50.55
9.76
0.0021 12.35
0.0027
0.0038
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
200
121.0
50.52
9.85
0.0021 11.92
0.0025
0.0038
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
200
125.5
51.34
9.76
0.0021 12.25
0.0026
0.0028
N
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
CA is sufficient.
129
Cond. Dehydrator
Stripping Gas Inlet
200
123.5
50.67
9.76
0.0021 12.05
0.0026
0.0028
N
130
Rewetted Stripping
Gas Outlet
250
123.0
49.90
9.77
0.0021 12.02
0.0026
0.0028
N
131
Rewetted Stripping
Gas Suct. Scrb.
Gas Outlet
250
123.0
49.90
9.77
0.0021 12.02
0.0026
0.0028
N
132
Rewetted Stripping
Gas Suct. Scrb.
Liq. Outlet
Rewetted Stripping
Gas Comp. Disch.
50
123.0
49.90
9.77
0.0021 12.02
0.0026
0.0028
N
250
126.0
51.73
9.77
0.0021 12.31
0.0026
0.0028
N
127
128
0
160.959
0.034
2.65
Very High
3
Notes
121
126
4.66
5691-GEN-PI-RPT-0005
95
134
Cond. Booster
Pumps Discharge
300
127.5
50.52
9.76
0.0021 12.44
0.0027
0.0028
N
135
Cond. Custody
Metering Inlet Hdr
300
127.5
50.52
9.76
0.0021 12.44
0.0027
0.0028
N
140
Dehydrated Gas
D/stream Stripping
Gas Tap Off
Main Dehydrated
Gas Header
2-Phase Export
Header
500
125.5
51.34
9.76
0.0021 12.25
0.0026
0.0028
N
600
124.5
52.87
9.76
0.0021 12.15
0.0026
0.0038
Y
NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
NACE is recommended for materials uniformity
CA is sufficient.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
4.67
2.05
0
0
6.01
Very Low
Note
95
Corplus gives "Very Low" results because of no
water content inserted but in reality there will be
water condensation due to temperature
differences. NACE is recommended for
materials uniformity in the system and to allow
souring through 25 yrs design life although the
pH2S is <0.003bar.
4.67
2.05
0
0
6.01
Very Low
Note
95
Corplus gives "Very Low" results because of no
water content inserted but in reality there will be
water condensation due to temperature
differences. NACE is recommended for
materials uniformity in the system and to allow
souring through 25 yrs design life although the
pH2S is <0.003bar.
No flowrates given in the H&MB, materials will be the same as other material in the
NACE is recommended for materials uniformity
system.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
4.66
2.05
0
0
5.87
Very Low
Note
95
Corplus gives "Very Low" results because of no
water content inserted but in reality there will be
water condensation due to temperature
differences. NACE is recommended for
materials uniformity in the system and to allow
souring through 25 yrs design life although the
pH2S is <0.003bar.
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
NACE is recommended for materials uniformity
CA is sufficient.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
NACE is recommended for materials uniformity
CA is sufficient.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
NACE is recommended for materials uniformity
CA is sufficient.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
600
121.0
51.46
9.77
0.0020 11.82
0.0024
0.0036
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
133
141
142
Where:
Cri: Inhibited Corrosion Rate; Cru: Uninhibited Corrosion Rate; A: Inhibitor efficiency; CA: Corrosion
Allowance.
CA = (Cri*(A %) /100*Design Life) + (Cru*(1-((A %) /100))*Design Life)
Ex: 0.1* 95%/100* 25yr + 7.09mm/yr* [1-(95%/100)]* 25yr = 11.237mm (Stream 1C Case 2C)
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
SERVICES FOR THIEN UNG FIXED PLATFORM
5691-GEN-PI-RPT-0005
REV. NO.
Material Selection and Corrosion
Philosophy Report
0
Page 26 of 33
Pipe
Size
DN(mm)
P
(bar)
T
(°C)
Upstream of Choke
Valve
Downstream of
Choke Valve
Gas from Test
Separator
150
55.0
77.00
9.68
Case3C: 10th Production Year
pH2S
pH2S
NACE pH
Gas flow
Oil flow Water flow Flow
CO2
Cru
A
CA
(bar)
(bar)
(Y/N)
(MMSCMD) (m3/h)
(m3/h)
velocity Corrosiveness (mm/yr) (%) (mm)
operating design
(m/s)
pressure pressure
0.0021 5.32 0.0012
0.0145
Y
4.98
1.08
14.972
2.314
15.05
Very High
3
95
6.13
150
54.5
76.85
9.78
0.0021 5.33
0.0011
0.0145
Y
4.98
1.08
14.962
2.314
16.21
Very High
3
150
54.5
76.85
9.78
0.0021 5.33
0.0011
0.0028
N
4.98
1.08
-
0
15.21
Very High
7.73
1D
Condensate From
Test Separator
150
54.5
76.85
9.78
0.0021 5.33
0.0011
0.0028
N
4.98
0
14.962
0
1.6
Very High
3
1E
Water From Test
Separator
150
54.5
76.85
9.78
0.0021 5.33
0.0011
0.0028
N
4.98
0
-
2.314
0.24
Very High
6.74
1F
FWS From Test
Separator
150
53.5
76.55
9.78
0.0021 5.23
0.0011
0.0028
N
4.98
1.08
14.942
2.312
16.21
Very High
3
2
Production Cooler
Inlet
250
53.5
76.55
9.78
0.0021 5.23
0.0011
0.0028
N
4.98
3.69
51.101
7.908
13.38
Very High
7.46
102
Production Cooler
Outlet
250
52.5
50.00
9.90
0.0021 5.20
0.0011
0.0028
N
5.03
3.6
61.833
8.515
6.79
High
2.56
103
Production
Separator Inlet
400
52.5
50.00
9.90
0.0021 5.20
0.0011
0.0028
N
5.03
8.41
144.638
19.918
15.89
High
3
104
Gas from
Production
Separator
Condensate From
Prod. Separator
500
52.5
50.00
9.90
0.0021 5.20
0.0011
0.0038
Y
8.41
0
0
9.93
High
2.75
300
52.5
50.00
9.90
0.0021 5.20
0.0011
0.0028
N
0
144.599
0.290
0.86
High
3
106
Water From Prod.
Separator
80
52.5
50.00
9.90
0.0021 5.20
0.0011
0.0028
N
107
Train 1 Dehydrated
Gas Header
500
161.0
50.00
9.93
0.0021 15.99
0.0034
0.0028
N
108
Lean TEG/Dehyd.
Gas HX Gas Outlet
600
51.0
53.70
9.94
0.0021 5.07
0.0011
0.0028
N
110
TEG Contactor Inlet
500
52.5
50.63
9.91
0.0021 5.20
0.0011
0.0028
N
111
Liq. From TEG
Contactor Inlet
Scrubber
Dehydrated Gas
From TEG
Contactor
Train 1 Dehydrated
Gas Header
50
52.5
50.63
9.91
0.0021 5.20
0.0011
0.0028
N
600
52.0
51.63
9.94
0.0021 5.17
0.0011
0.0038
Y
600
50.0
53.23
9.94
0.0021 4.97
0.0011
0.0028
N
150
600
161.0
161.0
50.00
50.00
9.94
9.94
0.0021 16.00
0.0021 16.00
0.0034
0.0034
0.0038
0.0038
Y
Y
NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
600
160.0
49.76
9.94
0.0021 15.90
0.0034
0.0038
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
600
157.5
49.16
9.94
0.0021 15.66
0.0033
0.0038
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
600
157.0
51.13
9.69
0.0020 15.21
0.0031
0.0036
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
150
57.5
50.25
9.90
0.0021 5.69
0.0012
0.0029
N
4.99
0
144.492
0.290
2.4
High
3
95
150
55.5
50.31
9.90
0.0021 5.49
0.0012
0.0029
N
5.01
0
144.572
0.290
2.4
High
3
95
Stream Stream Description
1A
1B
1C
105
112
113
114
115
116
117
118
119
120
Fuel Gas Tap Off
Gas Custody
Metering Inlet Hdr.
Gas Custody
Metering Outlet
Hdr. Gas to
Dehydrated
Static Mixer
Export to Subsea
P/L
Prod. Sep. Cond.
Pumps Discharge
Train 1 Cond. Filter
Outlet
CO2
H2S pCO2
(mol%) (mol%) (bar)
4.55
5.03
95
Notes
6.13
95 12.04 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
95
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
95 10.80 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
95
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
95 11.70 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
95
5.58 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
95
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
95 5.81
95
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
5.03
0
0.039
19.626
0.71
High
2.59
95
5.61 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
NACE is recommended for materials uniformity
CA is sufficient.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
NACE is recommended for materials uniformity
CA is sufficient.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
5.03
9.84
0
0
8.14
Very Low
Note 1 95
Corplus gives "Very Low" results because of no
water content inserted but in reality there will be
water condensation due to temperature
differences. NACE is recommended for
materials uniformity in the system and to allow
souring through 25 yrs design life although the
pH2S is <0.003bar
No flowrates given in the H&MB, materials will be the same as other material in the
NACE is recommended for materials uniformity
system.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
CA is sufficient.
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
SERVICES FOR THIEN UNG FIXED PLATFORM
Material Selection and Corrosion
Philosophy Report
Stream Stream Description
Pipe
Size
DN(mm)
P
(bar)
T
(°C)
REV. NO.
5691-GEN-PI-RPT-0005
0
Page 27 of 33
Case3C: 10th Production Year
pH2S
pH2S
NACE pH
Gas flow
Oil flow Water flow Flow
CO2
Cru
A
CA
Notes
(bar)
(bar)
(Y/N)
(MMSCMD) (m3/h)
(m3/h)
velocity Corrosiveness (mm/yr) (%) (mm)
operating design
(m/s)
pressure pressure
9.90 0.0021 5.40 0.0011
0.0029
N
5.02
0
144.606
0.037
2.4
High
3
95
6.13 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
9.90 0.0021 5.40 0.0011
0.0029
N
5.02
0
0
0.252
0.04
High
2.63
95
5.66 NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
10.17 0.0022 5.03 0.0011
0.0030
Y
5.05
0.01
143.629
0.037
0.14
High
1.78
95
4.60
CO2
H2S pCO2
(mol%) (mol%) (bar)
121
Train 1 Cond.
Coalescer Outlet
150
54.5
50.31
122
Water From Train 1
Cond. Coalescer
50
54.5
50.31
124
Train 1 Dewatered
Cond. D/S LV
Cond. From
Condensate
Dehydrator
Cond. Custody
Metering Outlet Hdr
150
49.5
50.21
350
50.0
49.78
9.93
0.0021 4.97
0.0011
0.0038
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
200
160.0
55.18
9.93
0.0021 15.89
0.0034
0.0038
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
Dehydrated Cond.
To Static Mixer
Stripping Gas Tap
Off
200
157.5
55.27
9.93
0.0021 15.64
0.0033
0.0038
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
200
52.0
51.63
9.94
0.0021 5.17
0.0011
0.0028
N
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
CA is sufficient.
129
Cond. Dehydrator
Stripping Gas Inlet
200
50.0
50.68
9.94
0.0021 4.97
0.0011
0.0028
N
130
Rewetted Stripping
Gas Outlet
250
49.5
49.64
9.95
0.0021 4.93
0.0010
0.0028
N
131
Rewetted Stripping
Gas Suct. Scrb.
Gas Outlet
250
49.5
49.64
9.95
0.0021 4.93
0.0010
0.0028
N
132
Rewetted Stripping
Gas Suct. Scrb.
Liquid Outlet
Rewetted Stripping
Gas Comp. Disch.
50
49.5
49.64
9.95
0.0021 4.93
0.0010
0.0028
N
250
52.5
54.37
9.95
0.0021 5.22
0.0011
0.0028
N
125
126
127
128
Cond. Booster
Pumps Discharge
Cond. Custody
Metering Inlet Hdr
Gas Comp.
24KQ110A/B-K10
Suction
Gas Comp.
24KV105A/B Liq.
Outlet
Gas Comp. After
Cooler 24E115A/B
Inlet
Gas Comp. After
Cooler 24E115A/B
Outlet
300
54.0
49.98
9.93
0.0022 5.36
0.0012
0.0030
Y
NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
NACE is recommended for materials uniformity
CA is sufficient.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
5.05
1.43
0
0
11.17
Very Low
Note 1 95
Corplus gives "Very Low" results because of no
water content inserted but in reality there will be
water condensation due to temperature
differences. NACE is recommended for
materials uniformity in the system and to allow
souring through 25 yrs design life although the
pH2S is <0.003bar.
5.05
1.43
0
0
11.17
Very Low
Note 1 95
Corplus gives "Very Low" results because of no
water content inserted but in reality there will be
water condensation due to temperature
differences. NACE is recommended for
materials uniformity in the system and to allow
souring through 25 yrs design life although the
pH2S is <0.003bar.
No flowrates given in the H&MB, materials will be the same as other material in the
NACE is recommended for materials uniformity
system.
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar.
5.03
1.43
0
0
10.51
Very Low
Note 1 95
Corplus gives "Very Low" results because of no
water content inserted but in reality there will be
water condensation due to temperature
differences. NACE is recommended for
materials uniformity in the system and to allow
souring through 25 yrs design life although the
pH2S is <0.003bar.
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
300
161.0
55.15
9.93
0.0022 15.99
0.0035
0.0030
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
500
50.0
53.23
9.94
0.0021 4.97
0.0011
0.0038
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
50
50.0
53.23
9.94
0.0021 4.97
0.0011
0.0038
Y
No flowrates given in the H&MB, materials will be the same as other material in the system.
400
162.0 165.79
9.94
0.0021 16.10
0.0034
0.0038
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
350
161.0
50.00
9.94
0.0021 16.00
0.0034
0.0038
Y
143A/B Gas Comp. Suct.
Scrb. 24V105A/B
Inlet
140
Dehydrated Gas
D/stream Stripping
Gas Tap Off
141
Main Dehydrated
Gas Header
142
2-Phase Export
Header
500
50.0
53.23
9.94
0.0021 4.97
0.0011
0.0038
Y
There will be a large temperature difference between the upstream and downstream of
the aftercooler and it is a concern if condensation will occur. However, according to
process group simulation, no condensation will occur since the air is dehydrated. In
case if condensation will occur, stainless steel tube will be recommended as an
alternative.
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
500
52.0
51.63
9.94
0.0021 5.17
0.0011
0.0028
N
600
161.0
50.00
9.93
0.0021 15.99
0.0034
0.0038
Y
NACE is recommended for materials uniformity
in the system and to allow souring through 25
yrs design life although the pH2S is <0.003bar
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
600
157.5
51.22
9.69
0.0020 15.26
0.0032
0.0036
Y
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm CA is sufficient.
133
134
135
136A/B
137A/B
138A/B
139A/B
Identified as dehydrated lines, therefore the corrosion is very minimal and LTCS 3mm
CA is sufficient.
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
SERVICES FOR THIEN UNG FIXED PLATFORM
REV. NO.
Material Selection and Corrosion
Philosophy Report
9.0
5691-GEN-PI-RPT-0005
0
Page 28 of 33
APPENDIX 2 – MATERIAL SELECTION TABLE
Stream/
Equipment
Description
No.
Process Piping
1A
Upstream of Choke Valve
1B
Downstream of Choke Valve
1C
Gas from Test Separator
1D
Condensate From Test Separator
1E
Water From Test Separator
1F
FWS From Test Separator
2
Production Cooler Inlet
102
Production Cooler Outlet
103
Production Separator Inlet
104
Gas from Production Separator
105
Condensate From Prod. Separator
106
Water From Prod. Separator
107
Train 1 Dehydrated Gas Header
108
Lean TEG/ Dehydrated Gas HX Gas /
Outlet
109
TEG Contactor Inlet Scrb. Inlet Header
110
TEG Contactor Inlet
111
Liq. From TEG Contactor Inlet Scrubber
112
Dehydrated Gas from TEG Contactor
113
Train 1 Dehydrated Gas Header
114
Fuel Gas Tap Off
115
116
117
118
119
120
121
122
Gas Custody Metering Inlet Hdr.
Gas Custody Metering Outlet Hdr.
Dehydrated Gas to Static Mixer
Export to Subsea P/L
Prod. Sep. Cond. Pumps Discharge
Train 1 Cond. Filter Outlet
Train 1 Cond. Coalescer Outlet
Water From Train 1 Cond.Coalescer
124
125
126
127
128
129
130
131
Train 1 Dewatered Cond. D/S LV
Cond. From Condensate Dehydrator
Cond. Custody Metering Outlet Hdr.
Dehydrated Cond. To Static Mixer
Stripping Gas Tap Off
Cond. Dehydrator Stripping Gas Inlet
Rewetted Stripping Gas Outlet
Rewetted Stripping Gas Suct. Scrb. Gas
Outlet
Rewetted Stripping Gas Suct. Scrb. Liq.
Outlet
Rewetted Stripping Gas Comp. Disch.
Cond. Booster Pumps Discharge
Cond. Custody Metering Inlet Hdr.
Gas Comp. 24KQ110A/B-K10 Suction
Gas Comp. 24KV105A/B Liq. Outlet
Gas Comp. After Cooler 24E115A/B Inlet
Gas Comp. After Cooler 24E115A/B Outlet
Gas Comp. Suct. Scrb. 24V105A/B Inlet
Dehydrated Gas D/stream Stripping Gas
Tap Off
132
133
134
135
136A/B
137A/B
138A/B
139A/B
143A/B
140
141
142
Main Dehydrated Gas Header
2-Phase Export Header
Recommended
Material/ Internal
Protection
Alternative
Material
DSS NACE
DSS NACE
DSS NACE
DSS NACE
DSS NACE
DSS NACE
DSS NACE
DSS NACE
DSS NACE
DSS NACE
DSS NACE
DSS NACE
LTCS + 3mm CA NACE
LTCS + 3mm CA NACE
Comments
NACE is recommended for
materials uniformity in the
system and to allow souring
through 25 yrs design life
although the pH2S is <0.003bar.
DSS NACE
DSS NACE
DSS NACE
LTCS + 3mm CA NACE
LTCS + 3mm CA NACE
CS + 3mm CA NACE
LTCS + 3mm CA NACE
LTCS + 3mm CA NACE
LTCS + 3mm CA NACE
LTCS + 3mm CA NACE
DSS NACE
DSS NACE
DSS NACE
DSS NACE
LTCS
LTCS
LTCS
LTCS
LTCS
NACE is recommended for
materials uniformity in the
system and to allow souring
through 25 yrs design life
although the pH2S is <0.003bar.
DSS NACE
+ 3mm CA NACE
+ 3mm CA NACE
+ 3mm CA NACE
+ 3mm CA NACE
+ 3mm CA NACE
DSS NACE
DSS NACE
NACE is recommended for
materials uniformity in the
system and to allow souring
through 25 yrs design life
although the pH2S is <0.003bar.
DSS NACE
LTCS
LTCS
LTCS
LTCS
LTCS
LTCS
LTCS
LTCS
DSS NACE
+ 3mm CA NACE
+ 3mm CA NACE
+ 3mm CA NACE
+ 3mm CA NACE
+ 3mm CA NACE
+ 3mm CA NACE
+ 3mm CA NACE
+ 3mm CA NACE
LTCS + 3mm CA NACE
LTCS + 3mm CA NACE
SS316L NACE
NACE is recommended for
materials uniformity in the
system and to allow souring
through 25 yrs design life
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
SERVICES FOR THIEN UNG FIXED PLATFORM
REV. NO.
Material Selection and Corrosion
Philosophy Report
Process Equipment
20V105
5691-GEN-PI-RPT-0005
0
Page 29 of 33
Test Separator
CS with Alloy 625
cladded
CS with SS316L
cladded*
*Usage of CS with SS316L
cladded requires qualification
testing by the Client
20E115
Production Cooler
20V110
Production Separator
DSS Tubes, CS with
Alloy 625 cladded
Header
CS with Alloy 625
cladded
CS with SS316L
cladded*
*Usage of CS with SS316L
cladded requires qualification
testing by the Client
22V105
TEG Contactor Inlet Scrubber
22V110
TEG Contactor
29M120
Gas / Condensate Static Mixer
30P105A/B/C
Train 1 Condensate Booster Pumps
30S110A/B
Train 1 Condensate Filters
30S115A/B
Train 1 Condensate Coalescers
30V105
Condensate Dehydrator
30V110
Rewetted Stripping Gas Suction Scrubber
Potable Water and Wash Water System Piping
From
To
Stream 1
Stream 2
Stream 3
Stream 4
Stream 5
Stream 6
Stream 7
Stream 8
Stream 9
Potable Water and Wash Water System Equipment
52T110
Potable Water Storage Tank
52P115A/ B
52V125
CS with SS316L cladded
CS with SS316L cladded
CS
HOLD
CS with SS316L cladded
CS with SS316L cladded
CS with SS316L cladded
CS with SS316L cladded
CuNi
SS316L
SS316L
SS316L
SS316L
SS316L
CS + 3mm CA
CS + 3mm CA
CS + 3mm CA
GRP
CS 3mm CA with epoxy
internal coating* or GRP
CS with SS316L
cladded/ solid
SS316L
*Coating to be approved by
HSE.
For the alternative material,
cladded or solid SS316L to be
selected depending on the
vessel dimension.
CS with SS316L
cladded/ solid
SS316L
*Coating to be approved by
HSE.
For the alternative material,
cladded or solid SS316L to be
selected depending on the
vessel dimension.
Potable Water Pumps
Pressurized Potable Water Vessel
SS316
CS 3mm CA with epoxy
internal coating* or GRP
52S120
Potable Water Filter
51T105
Wash Water Tank
51P110
Wash Water Pump
SS316L vessel and
internals
CS 3mm CA with epoxy
internal coating
CS
Seawater System Piping
From
To
Whole System
Seawater System Equipment
53P105A/ B
Seawater Lift Pumps
53T110A/ B
Seawater Lift Caissons
53S115A/ B
Seawater Strainer
CuNi
GRP
SDSS
CS 3mm CA internal
and external + glass
flake epoxy coating
internal and external +
sacrificial anode at the
bottom
SDSS
Ni-Al-Bronze
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
SERVICES FOR THIEN UNG FIXED PLATFORM
REV. NO.
Material Selection and Corrosion
Philosophy Report
Stream/
Equipment
Description
No.
Instrument and Utility Air System Piping
From
To
Stream 1
Stream 2
Stream 3
Stream 4
Stream 5
Stream 6
Stream 7
Instrument and Utility Air System Equipment
54V110
Wet Air Service
54V120
Instrument Air Receiver
Waste Heat Recovery and Hot Oil System Piping
From
To
Whole System
Waste Heat Recovery and Hot Oil System Equipment
56V115
Hot Oil Expansion Vessels
56P110A/ B Hot Oil Circulation Pumps
56S120
Hot Oil Side Stream Filter
56E125
Hot Oil Trim Cooler
Sewage System Piping
From
To
Stream 1
Stream 2
Stream 3
Sewage System Equipment
57T110
Sewage Water Disposal Caisson
Nitrogen System Piping
From
To
Stream 1
Stream 2
Stream 3
Stream 4
Stream 5
Stream 6
Stream 7
Stream 8
Stream 9
Stream 11
Nitrogen System Equipment
59V110
Nitrogen Receiver
5691-GEN-PI-RPT-0005
0
Page 30 of 33
Recommended
Material/ Internal
Protection
Alternative
Material
SS316L
SS316L
SS316L
SS316L
SS316L
SS316L
SS316L
Galvanized CS
Galvanized CS
Galvanized CS
Galvanized CS
Galvanized CS
Galvanized CS
Galvanized CS
VSP clarified that SS316L
stainless steel is necessary for
air before its cleaning but it is
preferable to apply galvanized
steel pipes after air cleaning [7],
[8].
CS 3mm CA with epoxy
internal coating
CS with SS316L
cladded or solid
SS316L
CS with SS316L
cladded or solid
SS316L
Cladded or solid SS316L to be
selected depending on the
vessel dimension.
Cladded or solid SS316L to be
selected depending on the
vessel dimension.
CS 3mm CA with epoxy
internal coating
CS + 3mm CA
CS + 3mm CA
CS
CS
CS + 3mm CA
GRP
GRP
GRP
CS 3mm CA internal
and external + glass
flake epoxy coating
internal and external +
sacrificial anode at the
bottom
SS316L
CS + 3mm CA
SS316L
CS + 3mm CA
CS + 3mm CA
CS + 3mm CA
CS + 3mm CA
CS + 3mm CA
CS + 3mm CA
CS + 3mm CA
CS 3mm CA with
internal coating
Comments
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
SERVICES FOR THIEN UNG FIXED PLATFORM
REV. NO.
Material Selection and Corrosion
Philosophy Report
Stream/
Equipment
Description
No.
Fuel Gas System Piping
From
To
Whole System
HP Flare System Piping
From
To
HP Flare Header
Liquid
Shutdown Valve (SDV)
Discharge
Outlet
Shutdown
HP Flare KO Drum Pumps
Valve (SDV)
HP Flare KO Production Separator
Drum Pumps
HP Flare KO HP Flare Tip
Drum
Process Drains Header
Recommended
Material/ Internal
Protection
5691-GEN-PI-RPT-0005
0
Page 31 of 33
Alternative
Material
LTCS + 3mm CA NACE
Comments
Lower design temperature below
0°C, impact testing shall be
performed.
VSP requires SS316L to be
applied from the filter to the
turbine.
SS316L LT
SS316L LT
6Mo
6Mo
CS 6mm CA with
coating and inspection
DSS
Due to the drum design
conditions.
DSS is recommended if material
uniformity with the production
line is a concern.
DSS
SS316L LT
6Mo
CS 6mm CA with
coating and inspection
SS316L
Solid SS316L with
external TSA coating
SS316
SS316
SS310 for temperature
exposed to oxidation/
scaling; SS316L
minimum for lower
temperature zones.
6Mo
CS 6mm CA with
coating and inspection
SS316L
Alternative of SS316L for robust
application to accommodate
25yrs design life
LP Flare KO HP Flare KO Header
Drum
CS 6mm CA with
coating and inspection
SS316L
Alternative of SS316L for robust
application to accommodate
25yrs design life
LP Flare KO LP Flare Tip
Drum
CS 6mm CA with
coating and inspection
SS316L
Alternative of SS316L for robust
application to accommodate
25yrs design life
CS 6mm CA with
Phenolic coating*.
CS with SS316L
cladded
*Phenolic coating selection shall
be qualified during detail
engineering due to the high
design temperature.
HP Flare System Piping Equipment
62V105
HP Flare KO Drum
62P115A/ B
62P115A/B
62A115
HP Flare KO Drum Pumps
HP Flare KO Drum Booster Pumps
HP Flare Tip
LP Flare System Piping
From
To
LP Flare Header
LP Flare System Equipment
62V125
LP Flare KO Drum
62P135A/B
62A130
LP Flare KO Drum Pumps
LP Flare Tip
CS
SS310 for temperature
exposed to oxidation/
scaling; SS316L
minimum for lower
temperature zones.
Material selection to be
confirmed with the vendor.
Material selection to be
confirmed with the vendor.
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
SERVICES FOR THIEN UNG FIXED PLATFORM
REV. NO.
Material Selection and Corrosion
Philosophy Report
Stream/
Equipment
No.
CPP Closed
From
CPP Closed
Drain Vessel
CPP Closed
Drain Vessel
Description
and Open Drain Systems Piping
To
LP Flare Header
CPP Closed Drain Vessel Pumps
CPP Closed HP Flare KO Drum
Drain Vessel
Pumps
CPP Open
Transfer Pots On CPP Celler Deck
Drain
Laydown Area
Caisson
CPP Closed and Open Drain Systems Equipment
64V115
CPP Closed Drain Vessel
64P120A/B
65P130
65T125
CPP Closed Drain Vessel Pump
CPP Open Drain Caisson Pump
CPP Open Drain Caisson
Aviation Fuel System
From
To
Whole System
Diesel Fuel System Piping
From
To
Whole System
Diesel Fuel System Equipment
67S105
Raw Diesel Coarse Filter
67T110
Diesel Storage Tank
67P115A/ B
67S120A/ B
Diesel Transfer Pumps
Diesel Filter Coalescers
Methanol Injection System Piping
From
To
Whole System
Methanol Injection System Equipment
68T115
Methanol Storage Tank
Recommended
Material/ Internal
Protection
5691-GEN-PI-RPT-0005
0
Page 32 of 33
Alternative
Material
Comments
CS + 3mm CA
CS 6mm CA with
coating and inspection
SS316L
CS 6mm CA with
coating and inspection
SS316L
CS 6mm CA with
coating and inspection
25Cr SDSS
CS with internal coating
CS with SS316L
cladded
CS with 13Cr impeller
SDSS
CS 3mm CA internal
and external + glass
flake epoxy coating
internal and external +
sacrificial anode at the
bottom
SS316
Ni-Al-Br
Alternative of SS316L for robust
application to accommodate
25yrs design life
Alternative of SS316L for robust
application to accommodate
25yrs design life
25Cr SDSS is only applicable if
the design temperature is to be
reduced during detail desing
engineering. Otherwise,
alternative material will be
limited to Titanium and Nickel
Alloy.
Coating to be qualified
depending to the service
conditions.
SS316L
CS + 3mm CA
CS 3mm CA and
SS316L internals.
CS 3mm CA and
SS316L internals.
CS
CS 3mm CA and
SS316L internals.
CS + 3mm CA
CS + 3mm CA
Corrosion Inhibitor Injection System Piping
From
To
Whole System
SS316L
Corrosion Inhibitor Injection System Equipment
68T105
Corrosion Inhibitor Storage Tank
SS316L
GRP
VSP has experienced using
GRP successfully for many
years.
DOC NO.
FRONT-END ENGINEERING DESIGN (FEED)
SERVICES FOR THIEN UNG FIXED PLATFORM
REV. NO.
Material Selection and Corrosion
Philosophy Report
Stream/
Equipment
Description
No.
FDP Closed and Open Drain Systems Piping
From
To
ANSI 900 Closed Drain Header
FDP Closed LP Flare Header
Drain Vessel
FDP Closed HP Flare KO Drum at CPP
Drain Vessel
FDP Open
HP Flare KO Drum at CPP
Drain
Caisson
Hazardous Open Drain Header
FDP Closed and Open Drain Systems Equipment
64V105
FDP Closed Drain Vessel
64P110A/B
65T105
FDP Closed Drain Vessel Pumps
FDP Open Drain Caisson
65P110
FDP Open Drain Caisson Pump
Recommended
Material/ Internal
Protection
Alternative
Material
5691-GEN-PI-RPT-0005
0
Page 33 of 33
Comments
CS + 3mm CA
CS + 3mm CA
DSS
DSS
GRP
CS with SS316L
cladded
SS316
CS 3mm CA internal
and external + glass
flake epoxy coating
internal and external +
sacrificial anode at the
bottom
SDSS
GRP used should be suitable for
maximum temperature.
Ni-Al-Br
Remarks:
1) Process equipments shall be NACE specified if materials specified in ANSI/NACE MR0175/ISO
15156 are being utilized.
2) Although NACE requirement is not specified for LP, HP and Closed & Open Drain System but it is
recommended that the vessels to be NACE specified. Vessels are considered as critical item where
in case of damages due to cracking in the future, the replacement will be expensive.
3) There is a proposal to route fluids from the open drain caisson to LP flare KO drum and going back to
the production separator. This will result in the possible introduction of seawater and oxygen into the
production system. This would have major implications on the materials of construction proposed and
therefore it is recommended that the proposal should not be adopted.
4) CRA materials being utilized beyond the temperatures specified in section 2.2.1 shall be painted.
5) Recommended coatings are preliminary and the actual coating system shall be as per the painting
specification.
6) All coating shall be qualified and approved for the intended services.