CA1049246A

CA1049246A - Drilling fluids containing phosphate ester acids

Info

Publication number: CA1049246A
Application number: CA200,605A
Authority: CA
Inventors: Walter J. Weiss; Thad O. Walker
Original assignee: Texaco Development Corp
Current assignee: Texaco Development Corp
Priority date: 1973-05-25
Filing date: 1974-05-23
Publication date: 1979-02-27
Also published as: AU6919374A; IE40147B1; ZA742914B; JPS5230273B2; JPS5010290A; GB1443654A; IE40147L; DK283974A

Abstract

DRILLING FLUIDS CONTAINING PHOSPHATE ESTER ACIDS
(D#73,131-F) ABSTRACT
Aqueous drilling fluids containing a minor amount of alkyl- or alkaryl-polyethyleneoxy phosphate ester acids are set forth. Such fluids are especially useful where high lubricity drilling muds are needed.
Another embodiment of this invention relates to a method of drilling utilizing the above-described fluids.

-I-

Description

D7~ ~ 3, l 31 m is invention relates to aqueouæ drilling fluids. More particularly, this invention relates to ~queous drilling fluids having incorporated therein a minor amount of an alkyl- or alkaryl-polyethyleneoxy phosphate ester acid. In another embodiment thls inven-tion is dlrected to an improved drilling operatlon employing the modified drilling fluids described above.
In a drilling operation, such as ln a rotary drilling operation, a drllling fluid i6 forced down the drill string, about the drill blt at the bottom of the borehole ~nd then back up to the surface. The dril~ing fluid employed in such a drilling operatlon u~ually is an aqueous drilling fluid and ls compounded of various materials in order to impart certain desirable physical and chemical properties to the drilling fluid. For example, thére is usually incorporated ln an aqueous drilling fluid a hydratable clayey material, such as a ; bentonite clay, to impart desirable viscoslty and gel strength properties to the drllling fluid BO as to better enable the drilling fluld to carry away the drilling cuttings from the bottom of the borehole. Other materials such as weighting agents, e.g., barium sulfate, are employed to increase the density of the drilling fluid so as to make the drilling operation more effective and safer by overcoming the fluid pressure within the formation being drilled. Other materials such as water loss improving agents, e.g., carboxy-methylcellulose, hydrolyzed starch, etc. are added to reduce the loss of fluid from the drilling fluid -1- ~

into the formation during the drilling operation. Still other materials such as corrosion inhibltors, bacteri-clde6 and drill bit lubricants are incorporated in the drllling fluid in order to impro~e the drllline operatlon and the drilling fluid.
Although a wide varlety of agueous drilling rlulds contalnlng materials deslgned to lncrease the lubrlclty of these fluld~ have been proposed and used ln the fleld, all of these ~odlfled drllllng flulds surfer ~rom one or more disadvantages.
In accordance with thls lnventlon an improved aqueous drilling fiuid is provlded by incorporating thereln a mlnor amount of a water-soluble phosphate ester acld or salt thereof Or the class consisting of compounds of the formula (I) ~ -(0CH2cH2)n - 0 - P - ORC
Ra oRb wherein n is an integer of from 4 to about 50; R le alkyl of from about 8 to about 12 carbon atoms and Ra 1B
selected from the group conslstlng of hydrogen and al~yl of from about 8 to about 12 carbon atoms; Rb ls selected from the group consistlng of hydrogen, R ~ ~(CH2cH2)n ~

wherein R, Ra and n are a~ previously deiined, and M, whereln M i8 a monovalent salt ~orming radical selected from the group consisting of alkali metal and ammonium radicals; and wherein Rc ls selected irom the group consisting of hydrogen and M a8 prevlously defined; and o~ the formula:
o (II) * (CH2cH2)n ~ - P - OR~
ORe wherein n is an integer o~ from about 4 to about 50;
~d is an alkyl of from about 8 to about 20 carbon atoms, Re i8 selected ~rom the group conslsting o~ hydrogen, Rd(OCH2CH2)n-, whereln Rd and n are as prevlously defined, and M, wherein M is a monovalent salt formlng radical selected from the group consisting of alkali metal and ammonium radlcals and wherein R~ ls selected from the group conæisting of hydrogen and M as pre-vlously defined. Use~ul alkali metal salts include sodlum, lithuim and potassium salts of the abo~e-descrlbed phosphates. Compounds of the types set out above where the total number o~ ethyleneoxy units ranges from 4 to about 20 are especially valuable phosphates ~or use ln the drilling fluids of this lnvention.
A drilling fluid of this inventlon may be pre-pared by the addition of a minor amount of at least one of the water-soluble phosphate ester acid~ or salts described abo~e to an aqueous drilling fluld or to an a~ueous drilling fluid containing a clay dispersed~
therein.
Water-soluble phosphate ester acids and salts o~ the types described above are avallable commercially ~a ~gls~e~ +~
from a number of manufacturers. For example, Antara~
LE-500, LS-500, LM-600, LE-700, LP-700 sold by GAF
Corporation, New York, New York, are typicaL water soluble phosphate ester aclds usefuL in this invention.
m e amount of the water-soluble phosphate ester acid or salt added to the well drilling fluid may be only a minor but surflc$ent amount to substantially increase the lubricity of the said drilllng ~luid ~s measured, for example, by torque reduction. Pre~erably, the amount of the water soluble phosphate ester acid or salt added to the well drilling fluld will be from about 0.01 to about 25 percent by weight.
It has been found that the drilllng ~lulds of this invention whlch exhiblt a high degree of lubrlcity will not cause an abnormal distortion of mud propertles, nor cauæe foaming o~ a degree that cannot be controlled by the use of defoamers which are c~mpatible wlth drllllng fluid systems. The novel drilling flulds of this invention show tolerance and stability over wider ranges in pH and electrolyte concentratlons and they perform satisfactorily in the various mud systems (i.e., drilling fluid systems) in general use today~
e.g., low and high pH, æea and salt water, as well a~
polymer, nondisper3ed and inhibiti~e mud systems.
Alkylpolyethyleneoxy phosphate ester acid~
and salts useful in the drilling fluids of this inven-tion include, for example:
O O
ll 11 C8Hl7(0CH2cH2)4-O_l_oH~ (C8Hl7(ocH2cH2)4-o)2-p-oH~
OH
O
Il 11 C8Hl7(ocH2cH2)5-o-i-o~a~ 8 17( 2 2)12 OH OE

o o CgHlg(OC~CH2)6-O-P-oH~ (C9Hl9(oc~2cH2)lo )2 OH

O O
ClOH21(C~2C ~)5- I-OH, Cl ~21(0CH2CH2)s_o_p_o O O
C12~25(0CH2CH2)15-0-P-OH, C14H29(0CH2~H2)35 OH OH

O O
(C14H29(0CH2CH2)9 )2 P ~ C14E2g(0CH2C~2)6-O-P-ONa ONa (C6H33(ocH2cH2)4-o)2-p-oH~ C16H33(0CH2CH2)5-0-P-OLi OLi Ol O
(C20H41(0c~2cH2)lo-o)2 P ~C20H4l(ocH2cx2)18 OLi Alkarylpolyethyleneoxy phosphate ester acids and salts which may be employed in the drilllng n uids of this invention include, for exQmple:
ICgHlg O
CgHlg_ ~ _ (CH2CH2)4 - O - P - OH, OH
CgHlg O
(CgHlg ~ _-~~~~(CH2cH2)6 - )2 ~ P - OH, 1~49246 9~19 ~ ( 2 2)7 1 ;

( gHlg ~ ~ (OCH2c}i2)5 - )2 (C10~21 ~ _ (0CH2CH2)12 - )2 o CloH21 -~ ( 2 2)6 C12~25 ~ - (0CH2CH2)5 - O - P - ONa, and OH

(CgHl7 - ~ _ (OCH2cH2)3s ~ )2 P OK

Mixtures o~ any of the above-deæcribed alkypolyethyleneoxy and alkarylpol~ethyleneoxy phosphate ester acids and salts may likewise be utilized in the novel drilling fluids of this invention.
The following examples which lnclude test data illustrate the surprising advantages o~ the use of alkyl-and alkaryl-polyethyleneoxy phosphate ester acids and salts in conventional drilling fluids and are to be considered not limitative.

EXAMPLE I
In this example one pound per barrel of Antara LP-700, an alkylpolyethyleneoxy phosphate ester sold by GAF Corporation, New York, New York in which the alkyl group is a mixture o~ alkyl~ derived from C12-C16 alcohols and in which the number of ethylene oxide units is about seven, waæ added to a low pH Louisiana Gulf Coast drilling fluid treated with 6 pounds per barrel o~
ferrochromelignosulfonate. The effect of the addition of thls phosphate acid ester on the properties o~ the drilling ~luid is set out in Table 1 which follows:

EFFECT ON DRILLING ~UD PROPERTIES
-Plaætic Yield API
Treatment Viæcosit ~ Point pH Fluid-Loss(cc) Base Mud 20.5 0lO.O 9.2 +l lb per bbl 22 0 9.5 8.8 Antara LP-700 +2 lb per bbL 21 0 9.6 8.8 Ant~ra LP-700 +3 lb per bbl 22.5 1.59.6 8.1 Antara LP-700 Plastic Viscosity is obtained by calculation, æub-~racting the Fann vlscosity reading at 300 rpm from the 600 rpm reading.
Tested in accordance with the procedure o~ API RP13B, November 1972.
The above results æhown in Table 1 indicate that there was no adverse effect of the treatment on the base mud and that there was no foaming.
The e~fect upon torque reduction of this same mud waæ obtained uæing a drilling mud lubricity tester and the results are reported in Table 2 which follows:

TORQUE MæASUREMæNTSl ON PHOSPHATE
ESTER ACID TREATED DRILLING MUD
1 lb/bbl 2 2 lb/bbl 2 Time Interval Treatment Treetment Before Treatment 15 min 8~o 7-9 30 min 8.2 7.9 45 min 8.5 8.5 60 min 8.7 8.8 10A~ter Treatment 15 min 7.0 5.8 30 min 7.0 5.6 45 min 6.2 5.6 60 mln 6.1 5.6 % Reduction of Torque 29.9 36.3 lThe values shown are dial readings whlch are directly proportional to the torque.
Antara LP-700 The data presented in Table 2 show that sub-stantiaL reductions in torque requirements are achieved with the above-identified treatment. Very little ~oaming was obser~ed in these tests.
EXAMPLE II
In a well drilling at 19097 ~eet in which an 8.9 lb/gal sodium chloride brine wa~ being used as the circulation fluid the torque requirements was measured and found to be 8000 ft. lbs. After two drums of the same alkyl-polyethyleneoxy phosphate ester acid as utilized in Example I had been added over a period o~
5.5 hours which represented one complete turnover of the mud, the torque at the end of 6 hours a~ measured .

was 3500 ft. lbs. This treatment corresponds to a 1/2 lb. of phosphate ester acld per bbl. of drilling fluid.
This data indicates the large reduction in torque achieved with the modi~ied drilling mud.
EXAMP~E III
To a salt water drilling fluid containing attapulgite clay (11 lbs/gal) in æodium chloride brine containing barite as a weighing agent belng used ln drilling a Gulf Coast well at 15,050 feet there is added over a period of 4.15 hours (one complete turnover of mud) su~icient phosphate ester acid of the ~ormula:
C9Hl9 ~ - (OCH2CH2)5 _ o - P _ CgHlg/ OH
to effect a treatment of 1.42 lb. of phosphate ester acid per barrel of drilling fluid. After addltion of the phosphate ester acid it is found that a significant reduction in torque requirement is achieved~
EXAMPLE IV
To a calcium base driLling ~luid (calclum hydroxide in a 10 lb/gal sodium chloride brine) being used in a West Texas well drilllng at 12480 feet there is added over a period o~ 3.47 hours (one complete mud turnover) 4 barrels o~ a phosphate ester acid salt of the formula:
o ClOH21 (C~2cH2),5 - O - I - ONa CloH21(0CH2CH2)5 - O
It is found that the torque requirement for rotation of the drill stem is substantially reduced on addition of the above-described phosphate ester acid salt.

_g _ EXAMPLE V
To a freæh water drilling fluid containing clay, barite and ferrochromelignosulfonate being used in drilling a Guli Coast well at 14,485 feet there is added over one circulatlon 4 bbl of phosphate ester acid o~ the iormula:
o (C12H25(0CH2CH2)~ )2 ~fter addition of phosphate ester acld it is ~ound that the drill stem torque requirement is slgniiicantly reduced.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An aqueous drilling fluid comprising an aqueous phase containing a minor amount of at least one phosphate compound of the class consisting of compounds of the formula:

(I) wherein n is an integer of 4 to about 50, R is alkyl of from about 8 to about 12 carbon atoms and Ra is selected from the group consisting of hydrogen and alkyl of from about 8 to about 12 carbon atoms; Rb is selected from the group consisting of hydrogen, , wherein R, Ra and n are as previously defined, and M, wherein M is a monovalent salt forming radical selected from the group consisting of alkali metal and ammonium radicals; and wherein Rc is selected from the group consisting of hydrogen and M as previously defined; and of the formula:

(II) wherein n is an integer of from 4 to about 50, Rd is alkyl of from about 8 to 20 carbon atoms; Re is selected from the group consisting of hydrogen, Rd(OCH2CH2)n-, wherein Rd and n are as previously defined, and M, wherein M is a monovalent salt forming radical selected from the group consisting of alkali metal and ammonium radicals and wherein Rf is selected from the group consisting of hydrogen and M as previously defined.

2. The aqueous drilling fluid of Claim 1 wherein the said phosphate compound has the formula:

wherein n is an integer of from 4 to about 50, R is alkyl of from about 8 to about 12 carbon atoms and Ra is selected from the group consisting of hydrogen and alkyl of from about 8 to about 12 carbon atoms; Rb is selected from the group consisting of hydrogen, wherein R, Ra and n are as previously defined, and M, wherein M is a monovalent salt forming radical selected from the group consisting of an alkali metal and ammonium radicals; and wherein Rc is selected from the group consisting of hydrogen and M is as previously defined.

3. The aqueous drilling fluid of Claim 1 wherein the said phosphate compound has the formula:

wherein n is an integer of from 4 to about 50, Rd is alkyl of from about 8 to about 20 carbon atoms; Re is selected from the group consisting of hydrogen, Rd(OCH2CH2)n-, wherein Rd and n are as previously defined, and M, wherein M is a monovalent salt forming radical selected from the group consisting of alkali metal and ammonium radicals and wherein Rf is selected from the group consisting of hydrogen and M as previously defined.

4. An aqueous drilling fluid comprising clay dispersed in an aqueous phase and containing a minor amount of at least one phosphate compound of the class consisting of the compounds of the formula:

(I) , wherein n is an integer of 4 to about 50, R is alkyl of from about 8 to about 12 carbon atoms and Ra is selected from the group consisting of hydrogen and alkyl of from about 8 to about 12 carbon atoms; Rb is selected from the group consisting of hydrogen, , wherein R, Ra and n are as previously defined, and M, wherein M is a monovalent salt forming radical selected from the group consisting of alkali metal and ammonium radicals; and wherein Rc is selected from the group consisting of hydrogen and M as previously defined; and of the formula:

(II) wherein n is an integer of from 4 to about 50, Rd is alkyl of from about 8 to about 20 carbon atoms; Re is selected from the group consisting of hydrogen, Rd(OCH2CH2)n-, wherein Rd and n are as previously defined, and M, wherein M is a monovalent salt forming radical selected from the group consisting of alkali metal and ammonium radicals and wherein Rf is selected from the group consisting of hydrogen and M as previously defined.

5. The aqueous drilling fluid of Claim 4 wherein the amount of the said phosphate compound employed is in the range of about 0.01 to about 25 percent by weight.

6. The aqueous drilling fluid of Claim 4 wherein n in the said phosphate compound is from 4 to about 10.

7. The aqueous drilling fluid of Claim 4 wherein the said phosphate compound has the formula:

, wherein n is an integer of from 4 to about 50, R is alkyl of from about 8 to about 12 carbon atoms and Ra is selected from the group consisting of hydrogen and alkyl of from about 8 to about 12 carbon atoms; Rb is selected from the group consisting of hydrogen, , wherein R, Ra and n are as previously defined, and M, wherein M is a monovalent salt forming radical selected from the group consisting of an alkali metal and ammonium radicals; and wherein Rc is selected from the group consisting of hydrogen and M is as previously defined.

8. The aqueous drilling fluid of Claim 7 wherein n in the said phosphate compound is from 4 to about 10.

9. The aqueous drilling fluid of Claim 4 wherein the said phosphate compound has the formula:

wherein n is an integer of from 2 to about 100, Rd is alkyl of from about 8 to about 20 carbon atoms; Re is selected from the group consisting of hydrogen, Rd(OCH2CH2)n-, wherein Rd and n are as previously defined, and M, wherein M is a monovalent salt forming radical elected from the group consisting of alkali metal and ammonium radicals and wherein Rf is selected from the group consisting of hydrogen and M as previously defined.

10. The aqueous drilling fluid of Claim 9 wherein n in the said phosphate compound is from 4 to about 10.

11. In a method of drilling wells wherein a drilling fluid is passed through the well in contact with earth formations during the drilling operation, the improvement which comprises treating said earth formations with an aqueous drilling fluid comprising clay dispersed in an aqueous phase and containing a minor amount of at least one compound of the class consisting of phosphate compounds of the formula:

(I) , wherein n is an integer of 4 to about 50; R is alkyl of from about 8 to about 12 carbon atoms and Ra is selected from the group consisting of hydrogen and alkyl of from about 8 to about 12 carbon atoms; Rb is selected from the group consisting of hydrogen, wherein R, Ra and n are as previously defined, and M, wherein M is a monovalent salt forming radical selected from the group consisting of alkali metal and ammonium radicals; and wherein Rc is selected from the group consisting of hydrogen and M as previously defined; and of the formula:

(II) wherein n is an integer of from 4 to about 50, Rc is alkyl of from about 8 to about 20 carbon atoms;

Re is selected from the group consisting of hydrogen, Rd(OCH2CH2)n-, wherein Rd and n are as previously defined, and M, wherein M is a monovalent salt forming radical selected from the group consisting of alkali metal and ammonium radicals and wherein Rf is selected from the group consisting of hydrogen and M as previously defined.

12. The method of Claim 11 wherein n in the said phos-phate compound is from about 4 to about 10.

13. The method of Claim 11 wherein the said phosphate compound is a Class II compound in which n is 7.

14. The aqueous drilling fluid of Claim 1 wherein the said phosphate compound is a phosphate ester acid salt.

15. The aqueous drilling fluid of Claim 14 wherein the said phosphate compound is:

.

16. The aqueous drilling fluid of Claim 1 wherein the said phosphate compound is:

.

17. The aqueous drilling fluid of Claim 1 wherein the said phosphate compound is:

.

18. The drilling method of Claim 11 wherein the said phosphate compound is:

wherein n is an integer of from 4 to about 50, R is alkyl of from about 8 to about 12 carbon atoms and Ra is selected from the group consisting of hydrogen and alkyl of from about 8 to about 12 carbon atoms; Rb is selected from the group consisting of hydrogen, wherein R, Ra and n are as previously defined, and M, wherein M is a monovalent salt forming radical selected from the group consisting of an alkali metal and ammonium radicals;
and wherein Rc is selected from the group consisting of hydrogen and M is as previously defined.

19. The aqueous drilling fluid of Claim 18 wherein the said phosphate compound is a phosphate ester acid salt.

20. The aqueous drilling fluid of Claim 1 wherein the said aqueous phase is a brine phase.

21. The aqueous drilling fluid of Claim 4 wherein the said aqueous phase is a brine phase.

22. The method of Claim 11 wherein the said aqueous phase is a brine phase.

23. The method of Claim 11 wherein the said phosphate compound is:

wherein n is an integer of from 4 to about 50, R is alkyl of from about 8 to about 12 carbon atoms and Ra is selected from the group consisting of hydrogen and alkyl of from about 8 to about 12 carbon atoms; Rb is selected from the group consisting of hydrogen, wherein R, Ra and n are as previously defined, and M, wherein M is a monovalent salt forming radical selected from the group consisting of an alkali metal and ammonium radicals;
and wherein Rc is selected from the group consisting of hydrogen and M is as previously defined.