Invert emulsion based drilling fluid and methods of using same

Patent metadata

Field	Value
Publication number	US-2018223166-A1
Application number	US-201715612397-A
Country	US
Kind code	A1
Filing date	Jun 2, 2017
Priority date	Feb 3, 2017
Publication date	Aug 9, 2018
Grant date	—

Abstract

A drilling fluid composition which includes a base fluid, one or more additives, and a viscosifier package. The base fluid is an invert emulsion comprising oil and water. Further, the one or more additives is chosen from an emulsifier, a weighting material, a fluid-loss control additive, or an alkaline compound. The viscosifier package includes a fatty acid having 6 or more carbon atoms and an aliphatic polyester. The drilling fluid composition has a yield point of from 30 lbf/100 ft2 to 100 lbf/100 ft2 and a low shear yield point of from 10 lbf/100 ft2 to 40 lbf/100 ft2. The associated method of drilling a subterranean well including operating a drill in a wellbore in the presence of the drilling fluid composition is also provided.

First claim

What is claimed is:

1 . A drilling fluid composition comprising:
a base fluid, where the base fluid is an invert emulsion comprising oil and water; one or more additives chosen from an emulsifier, a weighting material, a fluid-loss control additive, or an alkaline compound; and a viscosifier package, the viscosifier package comprising:
a fatty acid having 6 or more carbon atoms; and
an aliphatic polyester,

the drilling fluid composition having a yield point of from 30 lb f /100 ft 2 to 100 lb f /100 ft 2 measured according to API recommended practice 13-B2 in accordance with:
yield point=[2×(300 rpm reading)]−(600 rpm reading)

and a low shear yield point of from 10 lb f /100 ft 2 to 40 lb f /100 ft 2 measured in accordance with:
low shear yield point=[2×(3 rpm reading)]−(6 rpm reading).

2 . The drilling fluid composition of claim 1 where a weight ratio of fatty acid to polyester in the viscosifier package is 1:60 to 60:1.

3 . The drilling fluid composition of claim 1 where a weight ratio of fatty acid to polyester in the viscosifier package is 1:3 to 2:3.

4 . The drilling fluid composition of claim 1 where the drilling fluid composition comprises from 0.33 lb/bbl to 20 lb/bbl of the viscosifier package.

5 . The drilling fluid composition of claim 1 where the fatty acid is a long chain fatty acid having a carbon chain of 12 to 36 carbons.

6 . The drilling fluid composition claim 1 where the fatty acid has a carbon chain of 16 to 18 carbons.

7 . The drilling fluid composition of claim 1 where the aliphatic polyester is chosen from polylactic acid, polyglycolic acid, poly(lactic-co-glycolic acid), polycaprolactone, and polyhydroxybutyrate.

8 . The drilling fluid composition of claim 1 where the polyester comprises polylactic acid.

9 . The drilling fluid composition of claim 1 where the drilling fluid composition comprises less than 0.01 wt. % organoclay.

10 . The drilling fluid composition of claim 1 where the drilling fluid composition has a 10 second gel strength of from 10 lb f /100 ft 2 to 25 lb f /100 ft 2 as determined according to test methods provided in API RP 13B-2.

11 . The drilling fluid composition of claim 1 where the drilling fluid composition has a 10 minute gel strength of from 10 lb f /100 ft 2 to 50 lb f /100 ft 2 as determined according to test methods provided in API RP 13B-2.

12 . The drilling fluid composition of claim 1 where the fatty acid is a saturated fatty acid.

13 . A method of drilling a subterranean well, the method comprising:
operating a drill in a wellbore in the presence of a drilling fluid composition comprising:
a base fluid, where the base fluid is an invert emulsion comprising oil and water;
one or more additives chosen from an emulsifier, a weighting material, a fluid-loss control additive, or an alkaline compound; and
a viscosifier package, the viscosifier package comprising:
a fatty acid having 6 or more carbon atoms; and
an aliphatic polyester,

the drilling fluid composition having a yield point of from 30 lb f /100 ft 2 to 100 lb f /100 ft 2 measured according to API recommended practice 13-B2 in accordance with:
yield point=[2×(300 rpm reading)]−(600 rpm reading)

and a low shear yield point of from 10 lb f /100 ft 2 to 40 lb f /100 ft 2 measured in accordance with:
low shear yield point=[2×(3 rpm reading)]−(6 rpm reading).

14 . The method of drilling a subterranean well of claim 13 where a weight ratio of fatty acid to polyester in the viscosifier package is 1:60 to 60:1.

15 . The method of drilling a subterranean well of claim 13 where the drilling fluid composition comprises from 0.33 to 10 lb/bbl of the viscosifier package.

16 . The method of drilling a subterranean well of claim 13 where the fatty acid is a long chain fatty acid having a carbon chain of 12 to 36 carbons.

17 . The method of drilling a subterranean well of claim 13 where the fatty acid has a carbon chain of 16 to 18 carbons.

18 . The method of drilling a subterranean well of claim 13 where the aliphatic polyester is chosen from polylactic acid, polyglycolic acid, poly(lactic-co-glycolic acid), polycaprolactone, and polyhydroxybutyrate.

19 . The method of drilling a subterranean well of claim 13 where the drilling fluid composition has a 10 second gel strength of from 10 lb f /100 ft 2 to 25 lb f /100 ft 2 as determined according to test methods provided in API RP 13B-2.

20 . The method of drilling a subterranean well of claim 13 where the drilling fluid composition has a 10 minute gel strength of from 10 lb f /100 ft 2 to 50 lb f /100 ft 2 as determined according to test methods provided in API RP 13B-2.

Assignees

• Saudi Arabian Oil Co

Inventors

• Wagle Vikrant
• Al-Yami Abdullah
• Alhareth Nasser

Classifications

• C09K8/035

  Organic additives · CPC title

• C09K8/514

  of natural origin, e.g. polysaccharides, cellulose (C09K8/512 takes precedence) · CPC title

• C10N2030/06

  Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure · CPC title

• C10N2020/017

  Specific gravity or density · CPC title

• C10N2040/22

  with essential removal of material {, e.g. cutting, grinding or drilling} · CPC title