Scholarly article on topic 'Evaluation of some vanillin-modified polyoxyethylene surfactants as additives for water based mud'

Evaluation of some vanillin-modified polyoxyethylene surfactants as additives for water based mud Academic research paper on "Earth and related environmental sciences"

CC BY-NC-ND
0
0
Share paper
Academic journal
Egyptian Journal of Petroleum
Keywords
{Vanillin / "Polyoxyethylene surfactants" / "Water-based muds" / "Rheological properties" / Thixotropy / Filtration}

Abstract of research paper on Earth and related environmental sciences, author of scientific article — M.M.A. El-Sukkary, F.M. Ghuiba, G.H. Sayed, M.I. Abdou, E.A. Badr, et al.

Abstract Water-based drilling fluids are increasingly being used for oil and gas exploration and are generally considered to be more environmentally acceptable than oil-based or synthetic-based fluids. In this study, new types of vanillin-modified polyoxyethylene surfactants were evaluated as additives in water-based mud. Their rheological properties in water-based mud were investigated which included the apparent viscosity, the plastic viscosity, the yield point, the gel strength, the thixotropy as well as the filtration properties. Also, the effect of high temperature on the rheology of the formulated water based mud was studied. The tested ethoxylated non-ionic surfactants showed good results when utilized in the formulation of water-based mud.

Academic research paper on topic "Evaluation of some vanillin-modified polyoxyethylene surfactants as additives for water based mud"

Egyptian Journal of Petroleum (2014) xxx, xxx-xxx

Egyptian Petroleum Research Institute Egyptian Journal of Petroleum

www.elsevier.com/locate/egyjp www.sciencedirect.com

FULL LENGTH ARTICLE

Evaluation of some vanillin-modified polyoxyethylene surfactants as additives for water based mud

M.M.A. El-Sukkary b, F.M. Ghuiba b, G.H. Sayed a, M.I. Abdou b, E.A. Badr b, S.M. Tawfik b *, N.A. Negm b

a Chemistry Department, Faculty of Science, Ain Shams University, Cairo, Egypt b Egyptian Petroleum Research Institute, Nasr City, Cairo, Egypt

Received 19 February 2013; accepted 12 June 2013

KEYWORDS

Vanillin;

Polyoxyethylene surfactants; Water-based muds; Rheological properties; Thixotropy; Filtration

Abstract Water-based drilling fluids are increasingly being used for oil and gas exploration and are generally considered to be more environmentally acceptable than oil-based or synthetic-based fluids. In this study, new types of vanillin-modified polyoxyethylene surfactants were evaluated as additives in water-based mud. Their rheological properties in water-based mud were investigated which included the apparent viscosity, the plastic viscosity, the yield point, the gel strength, the thixotropy as well as the filtration properties. Also, the effect of high temperature on the rheology of the formulated water based mud was studied. The tested ethoxylated non-ionic surfactants showed good results when utilized in the formulation of water-based mud.

© 2014 Production and hosting by Elsevier B.V. on behalf of Egyptian Petroleum Research Institute.

1. Introduction

Drilling fluids or drilling mud was an essential component of the rotary drilling process used to drill for oil and gas in land and in offshore environments. The most important functions of drilling fluids are to transport cuttings to the surface; to balance subsurface and formation pressures preventing a blowout, to cool, lubricate, and support part of the weight of the drill bit and drill pipe [1,2]. During drilling, the drilling fluid

* Corresponding author. Tel.: +20 1273615278.

E-mail address: salahtwfk85@yahoo.com (S.M. Tawfik).

Peer review under responsibility of Egyptian Petroleum Research

Institute.

is pumped from the mud tanks down the hollow drill pipe and through nozzles in the drill bit. The flowing mud sweeps the crushed rock cuttings from beneath the bit and carries them back up the annular space between the drill pipe and the borehole or casing to the surface. The mud is then passed through solids control equipment (An integrated system of shale shaker screens and Hydro cyclones) to remove the cuttings. It is then circulated back to the mud tanks where the cycle is repeated. Traditionally drilling mud was classified according to the base used to prepare them, which is air, water or oil. Most drilling operations in the world use water-based fluids. Water based drilling mud were relatively inexpensive. Modern formulations are generally non-toxic to marine fauna. Discharged cuttings would disperse in the water column. Nevertheless, these had some disadvantages that can be overcome by the use of oil-based fluids [3]. The success of any well-drilling operation depended on many factors, one of the most important of which was the drilling fluid. Most crude

^jjfl I

Elsevier I Production and hosting by Elsevier

1110-0621 © 2014 Production and hosting by Elsevier B.V. on behalf of Egyptian Petroleum Research Institute. http://dx.doi.org/10.1016/j.ejpe.2014.02.002

petroleum oils have a low density and lack the required viscosity and gel strength properties of good oil. Thus, the drilling fluids were generally composed of crude oil, water, finely suspended solids and emulsifiers in order to give the required density and viscosity [1-4]. Surfactants were increasingly used in an ever-expanding variety of applications for the drilling fluids. In the oil-based drilling fluids, the most well-known applications of surfactants were the emulsifiers and wetting agents. In the water-based drilling fluids, there was a continually-growing variety of applications that include:

1. Oil-in-water emulsification in base fluid formulations.

2. Shale-swelling inhibitors to prevent well bore instabilities.

3. Detergency to prevent cuttings sticking to drill bit (adhesion of clay to metal parts).

4. Prevention of differential sticking dispersants to inhibit flocculation fluids for low-pressure reservoirs and hard-rock drilling.

5. Defoaming additives to clay particles.

6. Foaming additives to generate high gas/water ratio foam used as drilling fluid to eliminate undesirable foam in water-based fluids.

7. Surfactant-polymer complexes for enhanced properties in fluids for low pressure reservoir [5].

In the present work, new types of nonionic surfactant additives were used in designing drilling mud to tailor some functional requirements such as appropriate apparent viscosity, plastic viscosity, yield point, gel strength, and filter-loss control

property of the final product, according to the API standard test procedures [6].

2. Experimental

2.1. Synthesis

Synthesis and surface activity of tested surfactant were described in our previous work [7].

2.2. Measurements

2.2.1. Rheological properties

2.2.1.1. Mud formulation. Formulation of the mud was as follows:

1. The water based mud is a fresh water mud made of distilled water and bentonite clay 6.42% w/v as described by the American Petroleum Institute 13 1993A Specifications for Drilling Fluid Materials [8].

2. The samples were mixed in a Hamilton mixer for 20 min.

3. 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, and 0.5% of synthesized surfactants VE15, VE20, VE40, and VE60 were added to local bentonite mud batches.

4. Each sample was stirred for 15 min, before the rheo-logical and filtration properties were measured.

Rheological tests conducted in this study are based on the procedures recommended by the American Petroleum Institute (API). Apparent viscosity (AV), plastic viscosity (PV), and

Table 1 Effect of concentration of synthesized additives (VE15, VE20, VE40 and VE60) on rheological properties of water base mud.

Additives Conc. (w/v) AV (cP) PV (cP) Yield point (Ib/100 ft2) Gel strength at 10 s, (Ib/100 ft2) Gel strength at 10 min, (Ib/100 ft2) Thixotropy (Ib/100 ft2)

Blank 0 25 6 38 44 46 2

VE15 0.05 26.5 8 37 40 40 0

0.10 30.5 8 45 47 47 0

0.15 31.5 8 47 50 50 0

0.2 38.5 10 57 56 62 6

0.25 46.0 7 78 74 75 1

0.50 49.0 6 94 85 87 2

VE20 0.05 26.5 7 39 43 50 7

0.10 29.5 7 45 45 50 5

0.15 35.0 10 50 52 54 2

0.20 37.5 8 59 57 64 7

0.25 45.0 8 74 72 72 0

0.50 47.5 9 77 81 84 3

VE40 0.05 28.0 10 36 42 43 1

0.10 32.0 12 40 45 45 0

0.15 33.5 9 49 47 50 3

0.20 38.5 10 57 55 61 6

0.25 43.0 8 70 70 70 0

0.50 45.0 10 70 75 79 4

VE60 0.05 30.5 11 39 42 43 1

0.10 35.0 15 40 46 47 1

0.15 37.5 18 39 55 57 2

0.20 44.5 14 61 67 67 0

0.25 47.5 12 71 71 72 1

0.50 48.5 11 75 82 83 1

yield point (YP) were determined by calculating the relationship between shear rate and shear stress, where shear stress was taken from a dial reading that was in the degrees of a circle [9-12].

Equation 1 was used to calculate shear rate: Shear rate (s—') = rpm x 1.7034

Equation 2 was used to calculate AV: AV (cP) = 600 rpm reading/2

Equation 3 was used to calculate PV: PV (cP) = 600 rpm — 300 rpm reading

Equation 4 was used to calculate YP: YP (1b/100 ft2) = (reading at 300 rpm) — (plastic viscosity)

Viscosity of the mud is a function of temperature more than pressure. Commonly, it is necessary to measure viscosity at the elevated bottom hole temperature. This is done by using the viscometer cup-heater, chandler engineering laboratory Model API viscometer (Chan 35 Model 3500), which is a thermostat-controlled unit for heating the mud sample directly on a viscometer.

2.2.2. Determination of gel strength and thixotropy of the mud

The gel strength of a mud is a measure of the minimum shear stress necessary to produce slip-wise movement of fluid. Two readings are generally taken: (i) immediately after agitation of the mud in the cup, and (ii) after the mud in the cup has rested for 10 min. Thixotropy of the mud is the difference between the low readings after 10 s and 10 min [13].

2.2.3. Filter press

The test was carried out by using the API Fluid Loss Test (30 min, DP = 100 psi through No. 50 Whatman filter paper, ambient temperature, a standard filter loss Mode l107C) which is the standard static filtration test used in the industry. The experiment was run and the volume of filtrate reading was recorded from the graduated cylinder at the end of 30 min [13].

3. Results and discussion

3.1. Structure

The chemical structure of used additives surfactant is showed below.

3.2. Evaluation of the prepared ethoxylated surfactant as new additives for water based mud

3.2.1. Rheological properties

3.2.1.1. Apparent viscosity and plastic viscosity. From data in Table 2, the apparent viscosity (AV) and the plastic viscosity (PV) for the formulated water base mud (blank) are 25 and 6 cP respectively, but the values of AP and PV of the formulated mud increased with the added synthesized ethoxylated surfactant (VE15, VE20, VE40, and VE60) by different concentrations (0.05%, 0.1%, 0.15%, 0.2%, 0.25% and 0.5%). The results showed that the AV of the water based mud increased with the increase of the concentration of the surfactant additives to the mud and the value of AV ranged between 26.5 and 49 cP for VE15 which was greater than the AV of the water based mud (blank) (25 cP). These results may be explained in terms that the synthesized surfactants will form long molecule chains that will cause an increase in the drilling mud viscosity [14]. Also, at high salinity the bentonite platelets tend to flocculate. The addition of ethoxylated surfactant had also another effect. The ethoxylated surfactants could form a sealing layer around the clay platelets that will inhibit ion exchange between the clay platelets. VE15 and VE60 have the same chemical structure. Both have the Ethoxylated group on their structure, but VE60 has a higher EO (Degree of Eth-oxylation) rather than VE15. This caused VE60 to exert higher viscosity than VE15. As shown in Table 1, at low concentration of surfactants, there was a little difference between the apparent viscosities of different surfactants. But at high concentrations of surfactants this difference will be prominent. This is due to the surfactants structures, meaning the long eth-oxylated chain surfactants will make more viscous fluid than the short types at the same concentration. Thus the difference between them will become more obvious at high concentrations. As show in Table 1 the PV varied with irregular sequence by the concentration of different surfactants (VE15, VE20, VE40, and VE60) from 11 to 18 cP for VE60 as compared to the reference mud, which was 6 cP.

3.2.1.2. Yield point (YP). The yield point is dependent on the electro-chemical charges in the mud under flowing conditions. The particles may be charged so that they attracted each other giving a way to a high yield point, or particles might repel one another making the yield point lesser. In either case a yield point may be regulated by the use of chemical additives [15].

From Table 1 the YP ranged from 37 to 94 lb/100 ft2 for VE15, 39 to 77 lb/100 ft2 for VE20, 36 to 70 for VE40, and 39 to 75 for VE60, whereas the YP of the blank was 38 lb/

Ethoxylated Vanillin Surfactant

n = 15 (VE15) n = 20 (VE20) n = 40 (VE40) n = 60 (VE60)

R = ricinoleic acid (89.5%), linoleic acid (4.2%), oleic acid (3%), palmitic acid (1%), and stearic acid (1%)

ARTICLE IN PRESS

4 M.M.A. El-Sukkary et al.

Table 2 Effect of temperature on rheological properties of water based mud treated by 0.25% of synthesized additives (VE15, VE20, VE40 and VE60).

Additives (T OF) AV (cP) PV (cP) Yield point Gel strength at Gel strength at Thixotropy

(Ib/100 ft2) 10 s (Ib/100 ft2) 10 min (Ib/100 ft2) (Ib/100 ft2)

Blank 80 25 6 38 44 46 2

100 20 13 14 16 16 0

140 17.5 10 15 14 16 2

180 26 7 38 12 12 0

VE15 80 46 7 78 74 75 1

100 35 11 48 51 51 0

140 32 7 50 50 50 0

180 37.5 2 71 39 40 1

VE20 80 45 8 74 72 72 0

100 31.5 9 45 47 49 2

140 32 7 50 49 49 0

180 36 2 68 40 42 2

VE40 80 43 8 70 70 70 0

100 36.5 18 37 47 48 1

140 32 14 36 45 46 1

180 34.5 1 67 39 41 2

VE60 80 47.5 12 71 71 71 0

100 35.5 17 37 44 44 0

140 31.5 13 37 38 40 2

180 37.5 13 49 28 29 1

concentration which were 40 to 85 lb/100 ft2 for VE15, 43 to 81 lb/100 ft2 for VE20, 42 to 75 lb/100 ft2 for VE40, and 42 to 82 lb/100 ft2 for VE60, whereas the gel strength of the blank was 44 lb/100 ft2. The 10-min gel strength as show in Table 2 varied from 40 to 87 lb/100 ft2 for VE15, 50 to 84 lb/100 ft2 for VE20, 43 to 79 lb/100 ft2 for VE40, and 43 to 83 lb/ 100 ft2 for VE60 compared to 46 lb/100 ft2 for blank. This result revealed that the gel strength results for newly synthesized surfactant additives changed within the acceptable range compared to the field water-based mud (blank) [16].

3.2.2.2. Thixotropy. The thixotropy of water based mud formulated with VE15, VE20, VE40, and VE60 is shown in Table 1 some concentrations had no change in the values of 10 s and 10min gel strength measurement. This means that the thixotropy of the mud is equal to zero, so that the mud is more stable and can keep its rheological properties for a period of time during the drilling without losing its effectiveness. The gel strengths and thixotropy properties of the mud formulated with the prepared surfactants were comparable to the field water-based mud system using the local water base mud (blank). The gel strengths and thixotropy properties of the mud formulated with prepared surfactants VE15, VE20, VE40 and VE60 were comparable to the field water-based mud system using the local water base mud (blank) as shown in Fig. 2.

3.2.3. Effect of temperature on rheology

In Figs. 3-5 the apparent viscosity, the plastic viscosity and the yield point of the drilling mud at 80, 100, 140 and 180 0F are compared for drilling mud after the addition of the synthesized additives (VE15, VE20, VE40, and VE60) with a selected concentration 0.25%. As it can be seen, increasing the temperature from 80 to 140 of caused a significant decrease in the apparent

100 ft . Also the results revealed that the YP of the bentonite mud had been improved with increasing concentration of the added surfactants. The surfactants VE15, VE20, VE40 and VE60 were comparable to the field water-based mud system using the water based mud (blank) as shown in Fig. 1.

3.2.2. Determination of gel strength and thixotropy of the mud 3.2.2.1. Gel strength. Gel strengths of the water mud formulated with VE15, VE20, VE40, and VE60 by different concentrations after 10 s are shown in Table 1. The results show the gel strength after 10 s varied with different concentrations of surfactant additives from low concentration to high

Fig. 1 Rheology of water-based mud formulated with 0.25% newly synthesized surfactants; VE15, VE20, VE40, and VE60.

Fig. 2 Gel strength of water-based mud formulated with. 0.25% newly synthesized surfactants; VE15, VE20, VE40, and VE60.

and the plastic viscosity of the drilling mud the effect of increasing the temperatures on the dispersed suspensions of the drilling mud with the new additives can be explained by simple weakening of the strength of bonds between particles by thermal energy, this effect explained the decrease in the yield point [17]. Except at high temperature, 180 0F, the rheo-logical properties increased again than at low temperatures 100 and 140 of that may be due to the hydrogen bonding of the hy-droxyl group of ethoxylated surfactants with bentonite this means that synthetic additives are more efficient and had a higher temperature stability.

Fig. 4 Plastic viscosity versus various temperatures at 0.25% additives surfactants; VE15, VE20, VE40, and VE60.

Rheological properties varied with temperature for water based mud formulated with VE15, VE20, VE40, and VE60. Table 2 shows that the AV was 37.5, 36, 34.5 and 37.5 cP at 180 0F temperature for VE15, VE20, VE40, and VE60, respectively whereas that of the blank was 26 cP. Also, Table 2 showed PV of VE15, VE20, VE40, and VE60 as compared to the blank. Results showed that with a 100 to 180 of increase in temperature, the PV decreased from 11 to 2 cP for VE15, 9 to 2 cP for VE20, 18 to 1 cP for VE40 and 17 to 13 for VE60 whereas the blank decreased from 13 to 7 cP yield point increases with increase in temperature from 100 to 180 0F for the drilling mud with the synthesized surfactants Ib/100 ft2

110 130 150 170 190 Temperture (°F)

Fig. 3 Apparent viscosity versus various temperatures at 0.25% additives surfactants; VE15, VE20, VE40, and VE60.

Fig. 5 Yield point versus various temperatures at 0.25% additives surfactants; VE15, VE20, VE40, and VE60.

for VE20, VE40, and VE60, respectively whereas that of the blank increased from 14 to 38 Ib/100 ft2.

These results revealed that the effect of temperature on the rheological properties resulted for newly synthesized additives surfactant changed within the acceptable range compared to the field water-based mud (blank).

3.2.4. Effect of temperature on gel strength It can be deduced from Figs. 6 and 7 that as aging temperature increases, the 10 s gel strength and 10 min gel strength decrease simultaneously. It means that the longer the stagnation time, the harder the internal structures and more pressure will be required to initiate the flow of the fluid [18].

The gel strengths of the water-based mud formulated with VE15, VE20, VE40, and VE60 (0.25%) as compared with the blank are illustrated in Table 2. These results showed that

Fig. 6 Gel strength at 10 s versus various temperatures at 0.25% additives surfactants; VE15, VE20, VE40 and VE60.

Fig. 7 Gel strength at 10min versus various temperatures at 0.25% additives surfactants; VE15, VE20, VE40 and VE60.

with a temperature increase from 80 to 180 0F, the gel strength of VE15 decreased from 74 to 39 lb/ft2, the gel strength of VE20 decreased from 72 to 40 lb/ft2, the gel strength of VE40 decreased from 70 to 39 lb/ft2, the gel strength of VE60 decreased from 71 to 28 lb/ft2; whereas the gel strength of that of the blank varied from 44 to 12 lb/ft2 after 10 s. Table 2 shows the results of the gel strength after 10min. The gel strength clearly decreased from 75 to 40 lb/ft2, 72 to 42 lb/ft2, 70 to 41 lb/ft2 and 71 to 29 for VE15, VE20, VE40, and VE60 respectively, whereas it decreased from 46 to 12 for the blank. Table 2 shows the variations in thixotropy with temperature.

The increase in temperature caused unclear variation in thixotropy for VE15, VE20, VE40, and VE60 whereas the results showed no change in thixotropy with an increase in the temperature from 80 to 180 of. In some compounds there was no change in the values of 10 s and 10 min gel strength measurement. This means that the thixotropy of the mud is equal to zero. Therefore, the mud is more stable and can keep its rheological properties for a period of time during the drilling without losing its effectiveness .The test results for the gel strength and the thixotropy of the drilling mud with the newly synthesized additives under varying temperature conditions indicated that they gave superior results compared to the blank.

3.2.5. Filter press

The filtrate loss of water mud was measured under the effects of pressure (DP =100 psi) and ambient temperature. The mud formulated with the newly synthesized additives VE15, VE20, VE40, and VE60 showed lower filtrate losses than the field mud formulated blank. Thus, the newly synthesized additives caused the strongest bridging process and had better filtration characteristics than the blank. The filter loss results for formulated mud with the synthesized additives VE15, VE20, VE40, and VE60 are shown in Table 3 and found the best reduce in the filter loss for the synthesized compounds at concentration 0.25%. These results may be explained as follows: mud additives provide protection against water loss through three basic mechanisms: binding of free water, blocking pores and

Table 3 Effect of concentration of synthesized additives

(VE15, VE20, VE40 and VE60) on filter loss of water based

Additives Conc. (w/v) Filter loss 30 min

Blank 0 20

VE15 0.05 17.0

0.10 16.5

0.15 17.5

0.2 18.0

0.25 15.0

0.50 17.5

VE20 0.05 18.0

0.10 18.0

0.15 17.5

0.20 18.0

0.25 15.5

0.50 21.0

VE40 0.05 18.0

0.10 17.5

0.15 18.0

0.20 18.0

0.25 16.0

0.50 17.0

VE60 0.05 18.5

0.10 18.0

0.15 17.0

0.20 18.0

0.25 15.5

0.50 17.0

Fig. 8 Relationship between sheer rate and shear stress under varying temperatures for water-based mud using VE15 additives.

forming a tight filter cake [19]. The synthesized surfactants as well as bentonite have the ability to chemically bind water to the polar sites on the clay platelets or to the surfactant molecules and form a tight impermeable layer. Mud additives are effective because they bond all of the free water and make it difficult for the water to escape from the drilling mud. By binding the water the viscosity of the mud also increases and the

Fig. 9 Relationship between sheer rate and shear stress under varying temperatures for water-based mud using VE20 additives.

Fig. 10 Relationship between sheer rate and shear stress under varying temperatures for water-based mud using VE40 additives.

mud becomes more resistant to flow into the porous formation. The benefit of using bentonite and surfactants is that both of these substances had the ability to build an impermeable membrane over the porous formation.

3.3. Relationship between shear stress and shear rate

All shear stress values decreased at the same shear rate (10005 s-1) at the same temperature. At 80 0F, the shear stress value

80 ° F

1 10 100 1000 10000

Shear rate (S_1)

Fig. 11 Relationship between sheer rate and shear stress under varying temperatures for water-based mud using VE60 additives.

decreased from 98.16 to 78.96 lb/100 ft2, 96.03 to 76.82 lb/ 100 ft2, 91.76 to 74.69 lb/100 ft2 and 101.36 to 75.75 lb/ 100 ft2 for VE15, VE20, VE40 and VE60, respectively. At 100 of, the values decreased from 74.69 to 54.41, 67.22 to 50.14, 77.89 to 50.14 and 75.75 to 46.94 lb/100 ft2 for VE15, VE20, VE40 and VE60, respectively. At 140 of, the values decreased from 68.28 to 53.35, 68.28 to 52.28, 68.28 to 48.01 and 67.22 to 40.54 lb/100 ft2 for VE15, VE20, VE40 and VE60, respectively. At 180 of, the values decreased 80.02 to 41.61, 76.82 to 42.61, 773.62 to 42.61 and 80.02 to 29.87 lb/100 ft2 for VE15, VE20, VE40 and VE60, respectively; these data are illustrated in Figs. 8-11.

4. Conclusions

1. The results showed that the AV of the water based mud increased with the increase of the concentration of the surfactant additives to the mud.

2. The results revealed that the YP of the bentonite mud had been improved with increasing concentration of the added surfactants.

3. This result revealed that the gel strength results for newly synthesized additives surfactant changed within

the acceptable range compared to the field water based mud (blank).

4. Some concentrations had no change in the values of 10 s and 10 min gel strength measurement. This means that the thixotropy of the mud is equal to zero, so that the mud is more stable and can keep its rheo-logical properties for a period of time during the drilling without losing its effectiveness.

5. Increasing the temperature from 80 to 140 0F caused a significant decrease in the apparent and the plastic viscosity of the drilling mud.

6. The mud formulated with the newly synthesized additives VE15, VE20, VE40, and VE60 showed lower filtrate losses than the field mud formulated blank.

References

[1] H.C.H. Darley, G.G. Gray, Composition and Properties of Drilling and Completion Fluids, Gulf Publishing Co., Houston, TX, 1988, p. 643.

[2] J.M. Neff, Biological effects of drilling fluids, drill cuttings and produced waters, Elsevier Applied Science Publishers, London, 1987, pp. 469-538.

[3] E.F. Lucas, C.R.E. Mansur, L.S. Spinelli, Y.G.C. Queiros, Pure Appl. Chem. 81 (2009) 473-494.

[4] L.B. Rosa, M. Manuel, V. Helden, A. Kuindert, H. Mathieu, US Patent, 5,776,865 (1998).

[5] L. Quintero, J. Dispersion Sci. Technol. 23 (2002) 393-404.

[6] API (American Petroleum Institute), Recommended Practice for Field Testing Water-based Drilling Fluids API 13B-1, third ed., 2003 (ANSI/API 13B-1/ISO 10414-1).

[7] G.H. Sayed, F.M. Ghuiba, M.I. Abdou, E.A. Badr, S.M. Tawfik, N.A. Negm, J. Surfactants Deterg. 15 (2012) 735-743.

[8] American Petroleum Institute Specifications 13A, 1993, Specification for Drilling Fluid Materials.

[9] N.N. De-Bataafsch, German Patent 76,028 (1954).

[10] J. Rodolfo, Tailleur, US Patent 2,713,032 (1955).

[11] L.B. Rosa, M. Manuel, V. Helden, A. Kuindert, Muijs, H. Mathieu, US Patent, 9,532,260 (1995).

[12] J. Yan, F. Wang, G. Jiang, W. Fan, C. Su, Soc. Pet. Eng. 561 (1997).

[13] A.A. Hafiz, M.I. Abdou, J. Surfactants Deterg. 6 (2003) 243251.

[14] J.K. Fink, Oil Field Chemicals, Gulf Professional Pub., Amsterdam, Boston, 2003, p. 495.

[15] M.K. Ghassem Alaskari, R. Nickdel Teymoori, Int. J. Eng. Trans. B: Appl. 20 (3) (2007) 283.

[16] R.P. Bernhard, (M.Sc. thesis), Faculty of Texas Tech University, 1981.

[17] N. Teymoori, (M.Sc. thesis), Petroleum University of Technology, Ahwaz, Iran, 2007.

[18] K.H. Hiller, J. Pet. Technol. (1963) 779-789.

[19] F. Growcock, T. Harvey, Drilling Fluids Processing Handbook, Elsevier Inc., 2005, p. 57.