Preliminary Study of Purified Glycerol Palm Oil as WBM
Lubricant and Base Fluid SBM
Marbun, B. T. H.*, Aristya, R., Hutapea, P. A., Purba, N. R., Sisminardi Y. S.
Institut Teknologi Bandung, Bandung, West Java, Indonesia
bonar.marbun@tm.itb.ac.id, ramadhana.aristya@yahoo.com, philiphutapea@ymail.com,
nikopratamapurba@hotmail.com, yogasaktyanto@gmail.com
Abstract:
The application of glycerol by-product of palm oil biodiesel industry in drilling fluid
was carried out in this work. Glycerol will be utilized as a new alternative base fluid for
Synthetic-Based Mud (SBM) and lubricant for Water-Based Mud (WBM). Due to the
poor quality of crude glycerol from palm oil biodiesel industry, it needs to be purified
before its physio-chemical characterizations can be tested and formulated further. An
invert emulsion mud then developed using glycerol as base oil to study the emulsion
stability, rheological properties, and the effect of thermal conditioning to evaluate its
suitability for oil well drilling. The effect of glycerol as a lubricant additive in WBM on
the mud lubrication properties, rheology, filtration loss, and its compatibility with other
additives is also evaluated.
The preliminary tests result indicates that glycerol can be used as SBM in accordance
with the API standard and also can become the reference for this SBM development and
also has been proved to increase mud lubricating potential without affecting other
properties of drilling fluid significantly which is very potential due to its
environmentally friendly characteristics and low cost, since it may be obtained from an
abundant raw material from by-product of biodiesel production.
Keyword: Glycerol, synthetic-based mud, water-based mud
1. Introduction
Along with the increased productivity of biodiesel, the glycerol produced is also
increasing. Glycerol is by-product of transesterification process of vegetable oil to
produce biodiesel. The average amount of crude glycerol produced from biodiesel
production process is about 10% [1]. Lower prices and increased production quantities
will cause glycerol be not worth selling, giving rise to environmental problems caused
by glycerol waste.
In this study, glycerol was applied in the oil and gas industry as a drilling fluid. Due to
its biodegradable and lubricating nature, glycerol could be an alternative
environmentally friendly base fluid compared to diesel and common mineral oil, and
also lubricant for WBM. Glycerol used in this study is derived from palm oil biodiesel
production. However, purification process of poor quality crude glycerol from biodiesel
making process is necessary before its physio-chemical characterization can be tested
and then formulated further as base fluid for SBM and lubricant for WBM.
Glycerol (glycerine, glycyl alcohol, or 1, 2, 3- propanatriol) is a substance with three
hydroxyl group with characteristic of high viscosity, odorless, colorless, sweet
flavoured (0.6 times sucrose), and non-toxic material in its pure condition. Glycerol has
three hydroxil groups that are responsible for its solubility in water. Its hygroscopic
2
nature makes glycerol absorb water from the air. Glycerol molecular formula is C3H8O3
with molecular weight of 92.
Figure 1 Glycerol Molecular Structure
Table 1 Physio-Chemical Properties of Glycerol [2]
PROPERTY
Physical form
Purity
Melting point
Boiling point
Relative density
Vapour pressure
n-octanol -water
partition
coefficient
Water solubility
Dissociation
constant
Flash point
Autoflammibility
Viscosity
Surface tension
VALUE
Liquid
95 - 99.5% (water as an impurity with
trace levels polyglycerol)
18 deg C
290 deg C at 1013 hPa
1.26 at 20 deg C
0.000106 hPa at 25 deg C (calculated)
and 0.0033 hPa at 50 deg C (measured)
log Kow -1.76
Miscible
0.07E-13
160 deg C
393 deg C
1410 mPa.s at 20 deg C
63.4 mN/m at 20 deg C
Commonly, glycerol production from fats can be done through three methods, which are
saponification, hydrolisis, and transesterification. The transesterification of
tryglycerides with methanol is the current route to biodiesel production, generating fatty
acid methyl esters (biofuel) and glycerol. It can be estimated that from biodiesel making
process, around 10% of crude glycerol are produced [3]. This crude glycerol still
contains residual methanol, catalyst, and other compounds from vegetable oil as raw
material of biodiesel.
3
Figure 2 Crude Glycerol from Biodiesel Making Process
As a by-product of biodiesel industry, glycerol has not been widely processed so the
resale value is low. Glycerol market sector for each year continues to increase followed
by predictions of demand growth of biodiesel that produces glycerol as a by-product. In
recent years biodiesel industry is growing rapidly due to the depletion of fossil fuels
availability. Therefore, the world looking for alternative energy sources, one of which is
biodiesel. This condition causes the increase of global biodiesel production. In 2006,
U.S. biodiesel production reached 30-40 million gallons. If assumed, an increase in the
production of 50-80% per year, then in 2012 U.S. biodiesel production will reach 400
million gallons. Glycerol abundance due to increased production of biodiesel will cause
world crude glycerol prices to drop dramatically, even reaching the lowest level of
prices up to $ 0.05 per lb[1]. According to Tyson (2003) [4], an increase in biodiesel
production could increase production by 114% glycerol. This production increase must
be accompanied by expansion of the glycerol market.
2. Methods
2.1. Crude Glycerol as By-Product of Palm Oil Biodiesel Industry
In this study, crude glycerol that will be used derived from palm oil transesterification
reaction. Transesterification is the process of exchanging the organic group R" of an
ester with the organic group R' of an alcohol. Usually these reactions are catalyzed by
the addition of an acid or base catalyst. Chemical reaction of vegeteable oil
transesterification is shown in Figure 3. Triglycerides contained in palm oil are reacted
with an alcohol using alkaline catalyst to produce fatty acid alkyl esters and glycerol. In
this process, methanol is added as much as 15% (v/v) and mixed with KOH as much as
1% (v/v) of the total raw material olein / stearin oil to be processed to form methoxide
solution. Then olein/stearin oil and mixed with a solution of methoxide
transesterification reactor. Transesterification process lasted for 1 hour, stirring at a
temperature of 550 C with 100 rpm. Settling process is then performed to separate the
crude methyl ester and glycerol produced.
4
Figure 3 Reaction of Tryglicerides Transesterification [3]
Figure 4 Flow Diagram of the Process of Making Biodiesel [5]
Figure 5 Layer Formed on Transesterification Process of Triglycerides [5]
5
2.2. Purification of Crude Glycerol
Crude glycerol obtained directly from the separation of biodiesel is still contains many
impurities. Common compunds that cause impurities in crude glycerol are unreacted
methanol, soaps, and potassium hydroxide (KOH) catalyst [6] [7]. Methanol is one of
the reactants of the two main reactants in biodiesel production. Like an ordinary
chemical reaction, the efficiency of its use is not 100% so that in the end there is still a
residual unreacted methanol. Therefore the purification process is necessary to reduce
other useless chemicals. Impurities in glycerol, especially matter organic non-glycerol
(MONG), impact on the quality and quantity of glycerol generated. If level of MONG is
high (3-5%) problem of odor, colour, and flavor will arise in the resulting product.
Trimethylene glycol which includes MONG can affect the color of glycerol and cause
problems during storage [8].
Separation of impurities from glycerol can be done with addition of phosphoric acid [6].
The acid (Figure 7) will react with residual catalyst Potassium Hydroxide (KOH) to
form Potassium Phosphate salts (K3PO4). In addition, phosphoric acid will convert
soaps to form free fatty acids. Expected glycerol purity obtained from this method of
purification is 82.15% [5].
Figure 6 (A) Phosporic Acid Reaction with Residual Catalyst Potassium Hydroxide (B)
Phosporic Acid Reaction with Soap [5]
Figure 7 (A) Phosphoric Acid (B) 85% Phosphoric Acid Solution
6
Figure 8 Flow Diagram of Crude Glycerol Purification
2.3. Glycerol as Base Fluid for Synthetic-Based Mud
The fluid which would be used as base-fluid for development of SBM should be
analyzed first to determine its physio-chemical properties. By knowing these
parameters, an early description of mud composition and behavior could be estimated.
Parameters that should be tested are:
a) Specific Gravity
: shows the weight of base-fluid. This will indicates the
density of developed mud.
b) Pour Point
: shows the lowest temperature at which the base-fluid
still able to flow.
c) Flash Point
: shows the temperature at which the fluid begins to burn.
d) Kinematic Viscosity
: shows the resistance of base fluid to flow under the
influence gravity force.
Some researches have been conducted by other researchers in order to determine these
base fluid properties. Table 2 shows the comparison of glycerol, palm oil biodiesel, and
some mineral oils properties.
7
Table 2 Comparison of Glycerol Physical Properties With Some Base Oils
Parameter
Unit
Crude
Glycerol
(Hutapea,
2013)
SG
Cloud Point Celcius
Pour Point Celcius
Flash Point Celcius
1.09
24.4
4.4
82
Kinematic
Viscosity
N/A
cSt
Glycerol
After
Palm Oil
Purficati Biodiesel
on
(Hutapea,
(Hutapea,
2013)
2013)
1.24
0.9
<0
21.4
<0
5.9
99
250
N/A
Saraline
(Setya
wan et
al, 2007)
[9]
Sarapar
(Setya
wan et al,
2007) [9]
0.78
N/A
-16
81
0.76
N/A
-11
112
3.3
2.5
5
2.3.1. Additives Selection
Preliminary formulations of glycerol with certain additives were conducted in this
study. The following additives were selected for the developed glycerol synthetic-based
mud: primary emulsifier, secondary emulsifier, filtration control additive, viscosifier,
lime, and potassium chloride. For comparison, a mineral oil and palm oil biodiesel were
also formulated as base fluid using same spesification of additives. Mud formulation is
shown in Table 3.
Table 3 Mud Composition of Glycerol, Palm Oil Biodiesel, and Saraline SBM
Mud Components
Glycerol
Palm Oil
Biodiesel
Saraline
Base Fluid (ml)
Primary Emulsifier (ml)
Secondary Emulsifier (ml)
Duratone (ppb)
Lime (ppb)
KCl (ppb)
Water (ml)
Geltone (ppb)
273
3
2
4
5
17
70
6
273
3
2
4
5
17
70
6
273
3
2
4
5
17
70
6
Mixing
Duration
(min)
5
5
5
5
5
10
10
10
2.4. Glycerol as Lubricant for Water-Based Mud
Standard water based mud was formulated using bentonite as reactive clay. Glycerol
then added as additive with various concentrations. Test parameters include: lubricity
testing, plastic viscosity, yield point, gel strength, density, filtration test, and acidity of
mud filtrate.
8
3. RESULTS AND ANALYSIS
3.1. Glycerol Purification Results
Crude glycerol is mixed with 85% Phosphoric Acid (H3PO4) solution as much as 5%
(v/v). Solution then stirred using a stirrer for about 30 minutes. Solution formed settling
for 60 minutes to form three layers:
a) The bottom layer is a solid form of potassium phosphate salts (K3PO4)
b) The middle layer is glycerol (liquid)
c) The top layer is the residual of the free fatty acid (solid under room temperature)
Separation of glycerol, phosphate salts (K3PO4), and free fatty acid (FFA) is done by
using decantation and filtering method with funnel 200 mesh. In the screening process,
the top layer (FFA) and bottom (salt) simply left in a beaker, then the middle layer
(glycerol) is filtered. To make sure the salt is left behind in glycerol filtering process,
filtering is carried out using a filter press apparatus with pressure of about 30-50 psi.
This method differs from previous methods from Farobie (2009), wherein the method
using a burchner funnel to separate glycerol and FFA from phosphate salts first and then
followed by separation of glycerol from FFA using separating funnel. The bottom layer
then taken as pure glycerol.Residual photassium salt can be used as a fertilizer but still
requires a process of crystallization.
Figure 9 (A) Crude Glycerol and Phosphoric Acid Solution after 30 minutes Stirring
(B) After 60 Minutes Settling
Figure 10 (A) Residual Free Fatty Acids (B) Potassium Phosphate Salt
9
(A)
(B)
Figure 11 (A) Crude Glycerol (B) Purified Glycerol
3.2. Glycerol as Base Fluid for Synthetic-Based Mud
Figure 12 shows viscous charateristics of crude glycerol, glycerol, palm oil biodiesel,
and saraline. It can be seen that crude glycerol has very high dial reading compared to
other base fluids. The 200, 300, and 600 rpm reading went off scale when the fluids are
being tested. After purification process, glycerol shows better rheological properties
than before. However, the viscosity of purified glycerol still several times higher
compared to palm oil biodiesel and saraline. This would indicate the high viscosity of
formulated mud using glycerol as base fluid. A synthetic-based mud then developed
using glycerol, biodiesel, and saraline as base fluid and rheological test was conducted
before thermal aging and after 20 hours thermal aging at 302 o F. Table 4 summarizes all
rheological test results of the formulated muds.
300
Saraline
Palm Oil Biodiesel
Crude Glycerol
Glycerol
250
Dial Reading
200
150
100
50
0
0
100
200
300
400
500
600
700
Rotational Speed (rpm)
Figure 12. Viscosity Characteristics of Saraline, Crude Glycerol, Glycerol, and Palm
Oil Biodiesel
10
Table 4 Rheological Test Results of Glycerol, Saraline, and Palm Oil Biodiesel SBM
(BHR: Before Hot Rolling; AHR: After Hot Rolling)
Parameters
600 rpm
300 rpm
200 rpm
100 rpm
6 rpm
3 rpm
10 sec,
lb/100sqft
10 min,
lb/100sqft
PV, cp
YP, lb/100sqft
Glycerol
BHR
AHR
42
25
24
20
16
17
9
10
2
5
2
3
Saraline
BHR AHR
22
13
13
9
10
6.5
6
4.5
2
2
2
1.5
Biodiesel
BHR
AHR
51
34.5
29
22
21
17
13
10
3
2.5
3
2
2
8
3
2
4
1
4
18
6
11
5
15
4
9
4
2.5
4
5
5
22
7
2
12.5
9.5
3.2.1. Before Hot-Rolling
Figure 13 and 15 shows viscosity characteristics and gel strength of glycerol, biodiesel,
and saraline based mud before thermal aging. As expected before, SBM glycerol has
higher viscosity than the one formulated using saraline. Interestingly, formulated
glycerol SBM has much lower viscosity than glycerol itself. This can happen because
the reaction of glycerol with water at the mixing process. Glycerol is highly soluble in
water by forming hydrogen bond with water molecules. This solubility can cause the
viscosity of glycerol decreases significantly. However, the viscosity of glycerol SBM
still higher than saraline SBM. Gel strengths formed by glycerol SBM have the lowest
value compared to saraline and biodiesel SBM. This is indicating poor suspension
capacity of the mud that would lead to hole cleaning problem during drilling.
3.2.2. After Hot-Rolling
Figure 14 and 16 shows viscosity characteristics and gel strengths of glycerol, saraline,
and palm oil biodiesel SBM after thermal degradation using hot-rolling oven at 302 F
for 20 hours. The results show decrease of plastic viscosity from 18 cp to 5 cp followed
by increase of yield point from 6 to 15 lb/100ft2 and increase in low-shear viscosity. Gel
strength formed by glycerol SBM after thermal degradation is significantly increase and
several times higher than saraline and biodiesel SBM, but still in acceptable range. This
means at high temperature glycerol SBM will have better cutting suspension capacity
with good shear thinning rheological profile (as shown in Figure 14). However, the
increase in gel strength would lead to high circulation breakdwon pressure.
Those results indicating that glycerol could be used as environmentally friendly base
fluid for Synthetic Based Mud, but further research should be conducted to determine
the correct amount of water: glycerol ratio and viscosity modifier additives to obtain the
optimum rheological properties of the mud. Glycerol also cannot be treated as common
11
base fluid such as mineral oil and diesel because it cannot form an invert emulsion due
to its solubility nature with water. It is more proper to treat glycerol as base fluid for
Water-Based Mud with proper water: glycerol ratio, using water as media to carry
additives and clay while glycerol can be a lubricating and shale stabilzer agent of the
mud.
The other way to utilize glycerol as base fluid for SBM is by processing glycerol with
some kinds of fatty acid to produce glycerol ester of fatty acid, since it will give
glycerol an oil-like nature (insoluble in water) due to its “hydrophobic” fatty acid tail in
order to form invert emulsion mud with water.
Figure 13 Viscosity Characteristics of Glycerol, Saraline, and Biodiesel SBM Before
Hot Rolling
Figure 14 Viscosity Characteristics of Glycerol, Saraline, and Biodiesel SBM After Hot
Rolling (302 F, 20 hours)
12
12
11
10
9
8
7
6
5
4
3
2
1
0
10 Seconds Gel Strength
Glycerol
Saraline
10 Minutes Gel Strength
Biodiesel
Figure 15 Gel Strength of Glycerol, Saraline, and Biodiesel SBM Before Hot Rolling
12
11
10
9
8
7
6
5
4
3
2
1
0
10 Seconds Gel Strength
Glycerol
Saraline
10 Minutes Gel Strength
Biodiesel
Figure 16 Gel Strength of Glycerol, Saraline, and Biodiesel SBM After Hot Rolling
(302 F, 20 hours)
3.3. Glycerol as Lubricant Additive for Water-Based Mud
WBM that have been mixed with various concentrations of glycerol were tested in
laboratory to determine its rheological properties, lubricity, density, filtration loss, and
filtrate acidity. Table 5 shows the complete test results of the mud.
13
Table 5 Test Results of Water-Based Mud with Various Glycerol Concentrations
Parameters
Glycerol Concentration (%)
Lubricity Test
Film Strength (psi)
Rheology
600 rpm
300 rpm
200 rpm
100 rpm
3 rpm
10 sec, lb/100sqft
10 min, lb/100sqft
PV, cp
YP, lb/100sqft
LPLT Test
API Filtrate, ml
Filtrate pH
Mudcake Thickness, cm
Density, ppg
1
0
2
2
2118
2492
51
34
27
17
3
3
19
17
17
11.8
7.5
0.19
8.55
Test
3
5
4
10
5
15
4707
6051
7060
39
26
20
13
3
4
14
13
13
40
29
24
15
3
4
21
11
18
36
25
20
14
5
5
23
11
14
42
27
22
16
7
8
24
15
12
12
7
0.143
8.4
9.2
7
0.097
8.2
10.8
6
0.092
8.1
12
5.5
0.107
7.7
3.3.1. Lubricity
Lubricity test using Baroid EP/Lubricity tester Model 212 was conducted on formulated
WBM using glycerol as additive. Due to the limitations on the equipment, lubricating
potential of glyccerol as additive will no be determined by CoF (Coefficient of Friction)
of the developed WBM, but by determining film strength formed by the mud at extreme
pressure (EP). The EP tests are performed by applying a measured force with a torque
arm to a torque sensitive rotating bearing cup. This provides a means of testing
lubrication under extreme pressure conditions and produces an indication of the film
strength of the fluid being tested (Model 212 EP/Lubricity Tester Instruction Manual).
Equipment procedures for lubricity test and calculations for film strength determination
are attached in Appendixes.
It can be seen that WBM with glycerol at various concentrations have higher film
strength compared to standard WBM (0% glycerol concentration). As shown in Figure
17, the increase of mud film strength value is along with increase in the number
concentration of glycerol in the mud. With maximum glycerol concentration (15 %),
strength of film formed by the mud as a function of its lubrication properties has a value
up to 14,000 psi. This indicates that with appropriate amount, purified glycerol by
product of palm oil biodiesel process would be an effective additive to increase mud
lubricity on Water-Based Mud system.
14
16000
Film Strength
Film Strength (psi)
14000
12000
10000
8000
6000
4000
2000
0
0%
2%
5%
10%
15%
Glycerol Concentration
Figure 17 WBM Film Strength with Various Glycerol Concentrations
3.3.2. Rheological Properties
Table 5 shows that glycerol existences in WBM system tend to change the viscosity
characteristics of the mud. Plastic viscosity and yield point is decreased along with the
addition of glycerol. Dial reading of WBM with various concentrations of glycerol, as
seen in Figure 18, is slightly lower than standard WBM at same rotational speed.
However, the increase of glycerol concentration in the mud will also increase both its 10
seconds and 10 minutes gel strength value (shown in Figure 19). These results shows
that with utilization of glycerol as additive should be followed with addition of viscosity
modifier to maintain desired rheological properties of the mud according to drilling
program. Thus, glycerol-WBM system should be tested to see its suitability with other
additives.
80
Dial Reading
60
0% Glycerol
2% Glycerol
10% Glycerol
15% Glycerol
5% GLycerol
40
20
0
0
100
200
300
400
500
Rotational Speed (rpm)
600
700
Figure 18 Viscosity Characteristics of WBM with Various Glycerol Concentration
15
Gels Strength (lb/100 sqft)
28
24
10 Seconds Gel Strength
10 Minutes Gel Strength
20
16
12
8
4
0
0%
2%
5%
10%
15%
Glycerol Concentration
Figure 19 Gel Strength of WBM with Various Glycerol Concentrations
XCD Polymer (Xanthan Gum) as viscosity modifier is added to WBM with 5% glycerol
concentration. Figure 20 show that polymer were dissolved and works well in glycerolWBM system to increase the desired viscosifying properties. Dial reading of WBM with
5% glycerol and 3 ppb Polymer is significantly higher compared to WBM with only 5%
glycerol at same rotational speed. As expected from XCD Polymer addition, mud “low
end” rheology is also increased as the polymer is added to the system. This result shows
that glycerol does not affect WBM reactions with other additive, though further tests
still need to be conducted to other kind of additives such as filtration loss control,
salinity control, etc.
180
WBM + 5% Glycerol
160
WBM + 5% Glycerol + 3 ppb Polymer
140
Dial Reading
120
100
80
60
40
20
0
0
100
200
300
400
500
600
700
Rotational Speed (rpm)
Figure 20 Viscosity Characteristics of WBM with Glycerol and Polymer Additive
3.3.3. Filtration Loss
Figure 21 shows filtrate volume of WBM with various glycerol concentrations vs t^0.5.
After calculating spurt loss and determining fluid loss at 7.5 minutes, API fluid loss of
each sample then can be determined (shown in Figure 22). The result shows that there is
16
no significant impact of API filtrate loss compared to standard WBM (even slightly
decrease at 5% and 10% glycerol concentrations), which means that no extra amount of
filtration loss control additive is needed on the addition of glycerol in the mud system.
0% Glycerol
5% Glycerol
15% Glycerol
16
14
2% Glycerol
10% Glycerol
Filtrate Volume
12
10
8
6
4
2
0
0
1
2
t^0.5 3
4
5
6
Figure 21 Filtrate Volume vs Time^0.5 of WBM With Various Glycerol Concentration
14
API Fluid Loss
API Fluid Loss (cc)
12
10
8
6
4
2
0
0%
2%
5%
10%
15%
Glycerol Concentration
Figure 22 API Fluid Loss of WBM with Various Glycerol Concentration
Glycerol addition in WBM also has significant impact on mud cake thickness formed.
Figure 23 shows that along with increased amount of glycerol concentrations, mudcake
formed by the mud would also become thinner. This could be considered as a promising
result, since thin mudcake will minimize the risk of differential sticking to be happened
in drilling operations. Differential sticking can occurs when a portion of the drill string
(usually the drill collars) becomes embedded in the filter cake resulting in a nonuniform distribution of pressure around the circumference of the pipe.
Mudcake Thickness (cm)
17
0.2
0.18
0.16
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
Mudcake Thickness
0%
2%
5%
10%
15%
Glycerol Concentration
Figure 23 Mudcake Thickness of WBM with Various Glycerol Concentration
As shown in Figure 24, gycerol addition into WBM system have one disadvantage, it’s
reducing pH value of mud filtrate that would lead to several problems both in formation
drilled or in the wellbore itself. With 15% gycerol concentration, pH value of mud
filtrate is decreasing up to 5.5. This undesired result could be overcome by adding lime
or caustic soda to maintain proper pH value of mud filtrate.
8
Filtrate pH
7
pH
6
5
4
3
2
1
0
0%
2%
5%
10%
15%
Glycerol Concentration
Figure 24 Filtrate pH of WBM With Various Glycerol Concentration
4. CONCLUSIONS
1. Crude glycerol by-product of palm oil biodiesel industry has been successfully
purified using 85% H3PO4 solution as much as 5% v/v of crude glycerol with the
resulting glycerol content of more than 80%.
2. Synthetic-Based Mud using glycerol as base fluid has been developed. Rheological
properties tests before and after thermal degradation has been conducted in order to
evaluate its suitability in drilling operations. The results shows that glycerol SBM
still has relatively unstable rheological properties, thus further research need to be
18
conducted to find the correct additives for glycerol SBM or to process glycerol to
become glycerol ester with fatty acid before it is being utilized as base fluid for
SBM.
3. Water-Based mud system using various concentrations of glycerol as lubricant
additive has been formulated. Test results of WBM are :
a) Extreme Pressure test shows that increase in the glycerol concentration will also
increase WBM’s film strength.
b) Addition of glycerol in the WBM will increase both 10 seconds and 10 minutes
gel strength in the system, but it also slightly decrease viscosity characteristics of
formulated mud. Therefore, addition of glycerol as lubricant in WBM should be
coupled with addition of viscosity modifier additives to maintain desired
rheological properties of the mud.
c) WBM-glycerol system with 5% concentration has been tested to see its suitability
with other additive using XCD Polymer (Xanthan Gum) as viscosity modifier.
Test result shows that polymer were dissolved and works well in glycerol-WBM
system to increase the desired viscosifying properties.
d) There is no significant effect of addition of glycerol in mud API fluid loss, thus
means that no extra amount of filtration loss control additive is needed in the mud
system.
e) Along with increased amount of glycerol concentrations, mudcake formed by the
mud would also become thinner. This means the reduction of differential sticking
risk in drilling operation.
f) Glycerol will decrease pH value of mud filtrate. Decrease in pH value is
proportional to the addition of glycerol concentration in mud system. This
undesired result could be overcome by adding lime or caustic soda to maintain
proper pH value of mud filtrate.
5. REFERENCES
[1] Dasari MA. 2006. “Catalytic Conversion of Glycerol and Sugar Alcohols to Value
Added Product” [Dissertation]. Missouri: Universitiy of Missouri.
[2] SIDS Initial Assesment Report : Glycerol (CAS Number : 56-81-5). 2002. SIDS
Initial Assessment Meeting (SIAM), France.
[3] Soares, et al. 2011. “New Applications for Soybean Biodiesel Glycerol, Soybean Applications and Technology”, Prof. Tzi-Bun Ng (Ed.), ISBN: 978-953-307-2074, InTech, Available from: http://www.intechopen.com/books/soybeanapplications-and-technology/new-applications-for-soybeanbiodiesel-glycerol
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