INDUSTRY-ACADEMIA WORKSHOP
On
“Upstream Petroleum Technology”
30th May-1st June,2011
WELL PROGNOSIS
“PLANNING & MONITORING OF A DRILLING WELL”
Nababrot Gogoi
Dy. Suptdg. Geologist
Geology & Reservoir Dept
EXPLN & DEV
E&P CYCLE
Spudding
Drilling & Casing of
Conductor hole
(17.1/2”)
Rig-up & Installation
of all Rig
Equipments,
Infrastructure
Drilling & Casing of
Intermediate hole;
Intermediate OH
Logging (12.1/4”)
Initial tests,
Perforation, Unloading
by NPU / CTU /Gaslifts
Drilling of Oil
string/Production hole;
Convetional Coring
(8.1/2”)
Cased Hole
Logging
(CBL_VDL_USIT)
Well Completion
(Casing setting,
Cementation)
Open Hole Logging
(Resistivity, Density-neutron,
Sonic, MDT, Open Hole DST,
SWC)
Drilling Flow Chart
Released Locations
Exploratory
Generally first well on a
new structure/ new fault
closure to probe HC
prospects in different
geological formations.
Appraisal
Wells drilled on a
discovered structure for
ascertaining
reservoir
limit, OWC/GWC, HC vol
LOCATIONS
Development
Wells
drilled
for
production
purpose
from a known reservoir
and
limited
up
production potential as
per FDP.
WHY WE DRILL A
WELL?
BOTTOMHOLE BEHAVIOUR
Depth Data & Drilling Policy

GEOLOGICAL INFORMATIONS (STRUCTURE, PROSPECT, SUBSURFACE POSITION, POSSIBLE
FORMATION TOPS)

CASING POLICIES (SIZE, SETTING DEPTH, TYPE, CEMENTATION)

MUD POLICIES (PARAMETERS, COMPOSITIONS etc.)

DEVIATIONS {PROPOSED PLAN (BUILD-UP/HOLDING/DROPPING)}

INFORMATION OF POREPRESSURE / FOMATION PRESSURE FROM NEIGHBOURING WELLS

EXPECTED SUBSURFACE DRILLING COMPLICATIONS (LOSS ZONE, STUCK PIPE , TIGHT SPOTS)

SAMPLE COLLECTIONS , GAS LOGGING, CONVENTIONAL CORING

WIRELINE SERVICES

WELL COMPLETION AND PRODUCTION TESTING
WELL PROGNOSIS (DDDP / GTO)
BASEMAP
 SURFACE LOCATION MAP
 DISTANCE & BEARINGS W.R.TO NEIGHBOURING WELLS/STRUCTUERES
ISOPAY MAP
STRUCTURAL MAP
-STRUCTURAL CONFIGURATION
-CLOSURE (4 WAY/ FAULT)
-PROSPECT AREA
-FLUID MARGINS
Geological Information
GEOLOGICAL SECTION
LITHOLOGY
FORMATION
Alluvium + Dhekiajuli
Namsang
Girujan
Tipam+Surma
Barail
Kopili
-PROSPECT LEVEL
-UPDIP/DOWNDIP W.R.TO NEIGHBOURING WELLS
-PRESSURE-PRODUCTION BEHAVIOUR OF NEIGHBOURING WELLS
-LITHOCOLUMN INDICATING EXPECTED FORMATION TOPS (BASED ON
SEISMIC DATA & NEIGHBOURING WELLS)
Prang
Narpuh
Lakadong + Therria
Langpar
Basement
Geological Information
CASING IS LOWERED & SET TO :

PROTECT & MAINTAIN THE HOLE

FACILITATE FLOW OF OIL/GAS FOR LONG PERIODS OF TIME
CASING POLICY
FACTORS TO CONSIDER FOR CASING DESIGN:
 Total depth of well
 Pore pressure, fracture gradients, geothermal gradient
 Presence of shallow gas pockets / Boulder, Pebble bed
 Critical zones
 Depth of potential prospect zones
 Time limits on open hole drilling
 Casing program compatibility with existing wellhead systems
 Casing program compatibility with planned completion programme on
production wells
 Casing availability: size, grade and weight
 Economics – drilling time, casing lowering time, cost of materials & other
equipments
Casing Policy
Vertical Well
J-Bend
S-Bend Well
Horizontal Well
WELL PROFILE
17.1/2˝
(13.3/8˝)
Alluvium/ Namsang
26˝
(20˝)
All/Nam
26˝
(20˝)
17.1/2˝
(13.3/8˝)
12.1/4˝
(9.5/8˝)
36˝
(30˝)
Girujan
Girujan
12.1/4˝
(9.5/8˝)
17.1/2”
(13.3/8˝)
Barail/Kopili
12.1/4˝
(9.5/8˝)
8.1/2˝
(5.1/2˝)
Lk+Th/Langpar
8.1/2˝
(5.1/2˝)
Lk+Th/Langpar/
8.1/2˝
(5.1/2˝)
Basement
TD: < 4000 m
TD: > 4000 m
TD: > 5000 m
CASING DESIGN: VERTICAL & DEVIATED WELLS
HORIZONTAL WELL
17.1/2˝
(13.3/8˝)
Alluvium/ Namsang
1000-1500 m
12.1/4˝
(9.5/8˝)
400 m
Girujan
8.1/2˝
(7” Liiner)
Prospect
6˝
(4.1/2” Slotted LIiner
CASING POLICY
Drilling Fluid Policy
DRILLING FLUID
IT’S A SYSTEM TO PROVIDE A SUITABLE MEDIUM FOR CARRYING OUT EFFECTIVE
AND EFFICIENT DRILLING OPERATIONS AND TO IMPART BOREHOLE STABILITY
FUNCTIONS OF DRILLING FLUID:

PROTECT HOLE FROM COLLAPSE

CUTTINGS REMOVAL FROM THE BIT TO THE SURFACE

CONTROL FORMATION PRESSURE

COOLING AND LUBRICATION

AID IN FORMATION EVALUATION
DRILLING FLUID
FUNCTIONS OF DRILLING FLUID:

HOLD
CUTTINGS
AND
WEIGHT
MATERIALS
IN
SUSPENSIONS,
WHEN
CIRCUALTION STOPPED

SUPPORTING A PART OF THE WEIGHT OF DRILL PIPE AND CASING (i.e. BOUYANCY)

IN TRANSMITTING HYDRAULIC HORSEPOWER TO THE BIT

ACTING AS MEDIUM FOR WIRELINE LOGGING

ENSURING MAXIMUM INFORMATION ABOUT THE FORMATIONS PENETRATED

ACTING AS A MEDIUM FOR HORIZONTAL DRILLING SIGNAL IN PULSES
DRILLING FLUID
TYPES OF DRILLING FLUID
OIL BASE
PNEUMATICS
WATER BASE
OIL BASE MUD (OBM): Oil the continuous phase with other chemicals
WATER BASE MUD (WBM): Water the continuous phase with Bentonite
PNEUMATICS: Used predominantly air or gas as the circulating medium
PROPERTIES OF DRILLING FLUID
Weight, Temperature, Funnel viscosity, Plastic viscosity, Yield point, Gel
strengths, Water losses, Filter cake, Sand content, Solids content, Oil content,
Calcium content, Salinity
DRILLING FLUID
DEVIATION POLICY
DEVIATION
CRITERIA FOR DEVIATED WELLS

LOGISTICS, LAND ACQUISITION, CLUSTER PLINTH
DEVIATION METHODS

SS READING, MWD READING
DEVIATION CALIBRATION METHODS

AVERAGE ANGLE METHOD

RADIUS OF CURVATURE METHOD

MINIMUM CURVATURE METHOD

TANGENTIAL METHOD

BALANCED TANGENTIAL METHOD
DEVIATION
 WELLBORE STABILITY & FLUID LOSS/KICK
 PORE PRESSURE ANALYSIS
 STUCK PIPE EVENTS/ DRILLING EVENTS
LOSS CIRCULATION, PIPE STUCK AND OTHER EVENTS
GTO (Geo Technical Order)
It’s a glimps:
 GEOLOGICAL DATA
 PORE PRESSURE
PREDICTION
 FORMATIONS
 DEPTHS vs DAYS
 WELLHEAD DATA
 CASING SEAT
 MUD DATA etc.
GEO TECHNICAL ORDER
SELECTION, COLLECTION, PREPARATION, EXAMINATION, DESCRIPTION OF
DRILL-CUTTINGS, SIDE WALL CORE AND CONVENTIONAL CORE SAMPLES
 LITHOLOGICAL DESCRIPTION:
 COLOUR, HARDNESS, FRAMEWORK GRAIN IDENTIFICATION, MATRIX, GRAIN
SIZE, SORTING, ANGULARITY
 HYDROCARBON INDICATION:
 GAS DETECTION: GAS CHART INTERPETATION (ZERO GAS, BACKGROUND GAS,
TRIP GAS, GAS SHOWS, CONNECTION GAS, RECYCLE GAS
 OIL SHOWS: ODOR, STAIN, BLEEDING, COLOUR (Dark brown to Pale),
FLUORESCENCE (Dark brown, Golden yellow, Light yellow, Bluish)
 RECORDING OF GAS READING & GAS CHROMATOGRAPHY
 PREPARE & MAINTAIN FLUSH SAMPLE LOGS/ CUTTINGS LOGS/ MASTER LOGS
 CORRELATE WITH NEIGHBOURING WELLS
SAMPLE COLLECTION, GAS LOGGING, CONVENTIONAL CORING
Typical Flush Sample/Cuttings Log/ Master Log
“IT’S A PICTORIAL PRESENTATION OF DIRECT OBSRVATIONS OF LITHOLOGY FLUSHED OUT FROM BOTTOM
HOLE & IT’S FLUORESCENCE ALONG WITH GAS READING, ROP, HYDRULICS, DRILLING EVENTS W.R.TO DEPTH”
THE FIRST
INFORMATION OF
SUBSURFACE
GEOLOGY
FLUSH SAMPLE LOG
“GEOPREMIUM SOFTWARE”
MASTER LOG
COMPOSITE LOG
DRILLING DYNAMIC LOG

ROP, GAS READING, BIT INFORMATIONS, LITHOLOGICAL DESCRIPTION,
FLUORESCENCE etc. ONLINE MONITORING OF DRILLING, GEOLOGICAL &
MUD PARAMETERS IN “MLU’
FLUSH SAMPLE LOG
WIRELINE LOGS
OPEN HOLE
CASED HOLE
• Resistivity Logs
• Density-Porosity Logs
•
GR-CCL
• GR, GR Spectrometry
•
GR-NEUTRON-CCL
• Sonic Tools
•
VSP
• Vertical Seismic Profiling (VSP)
•
CBL-VDL
• Dipmeter, Inclinometer (Strike, Dip)
•
USIT / CAST-V
• Borehole Imaging Tool (XRMI / FMI)
•
TTP / HSC
• Caliper
•
BP, RP, TTBP
• Wireline Testing & Sampling (MDT/
•
RMT / RST
•
WFL
•
PLT
RDT)
• Neutron Tools
• NMR /MRIL
• Tool Pusher Logging
WIRELINE LOGS
RECOMMENDING CORING
During Drilling
By Wireline (CST)
SideWall Core
Petrology
&
Conventional Core
Mineralogical
study,
Permeability
(Vertical,
Lateral),
Capillary
Sedimentological Study (Grain size, Shape,
Study, Sedimentary Structures, Environment
Sorting), Petrographic Study (Thin Section,
of Deposition including all studies as in
XRD,
SWC/CST
SEM),
(Palaoentology,
Mechanics,
Biostratigraphic
Study
Playnology),
Rock
Geochemistry,
Reservoir
Characteristics (porosity, Permeability, oil
saturation, Oil content, Water content)
RESPONSIBILITY
ELAN Interpretation
Why we need
CBL-VDL-USIT logs?
Open Hole Composite
CBL_VDL
PERFORATIONS:
 Selection of
3893.0
Perforation Range
3900.0
3901.0
 Gun type, Perforation
Density SPF), Phasing,
3919.0
3920.5
Total Depth Of
Penetration
3941.0
Fluid uncertain:
Perforation:
SWC, Perforation
ROLE OF OPERATION GEOLOGIST

EXAMINATION OF DRILLCUTTINGS IN HAND SPECIMEN & UNDER
MICROSCOPE FOR IDENTIFICATION & DESCRIPTION OF LITHOLOGY

IDENTIFICCATION OF HC BEARING ZONES BY EXAMINING SAMPLES UNDER
FLUOROSCOPE FOR FLUORESCENCE ( YELLOW, YELLOWISH WHITE etc.
INDICATE OIL / BLUISH WHITE INDICATE GAS / NO FLURORESCENCE
INDICATE WATER )

CORRELATION & SECTION PREPARATION
GEOLOGISTS’ RESPONSIBILTY
ROLE OF OPERATION GEOLOGIST

OIL STRING CASING POLICY (SHOE, FLOAT COLLAR, SHORT JOINTS, CENTRALISER,
SCRATCHERS)

OIL STRING CEMENTATION POLICY (OVERGAUGE, TRUE GAUGE, UNDERGAUGE,
VOLUME OF CEMENT REQUIRED, CEMENT TOP etc.)

INITIAL TESTING POLICY (ZONE TO BE TESTED, PRODUCTION STRING, PACKER, GLVs
etc.)

BULLET PERFORATION NOTIFICATION (BPN)- DETAILS ON PERFORATIONS GUN TYPE,
SPF, CHARGES etc.
GEOLOGISTS’ RESPONSIBILTY
GEOLOGICAL CROSS SECTION
GEOLOGICAL CORRELATION

GEOLOGISTS PLAYS PIVOTAL ROLE DURING
DRILLING OF A WELL, FROM SPUDDING TILL INITIAL
TESTING / RIG DOWN.

ALL MAJOR DECISIONS ARE TAKEN BY G&R DEPT.

DRILLING OPERATION ACTIVITIES ARE AN INTEGRATED
TEAM EFFORT INCLUDING G&R, DRILLING, CHEMICAL,
PRDUCTION DEPTS
Perforation:
CONCLUSIONS
THANK YOU
Sunset in Libya
@ nababrot gogoi
Perforation: