Drilling lost circulation material

Patent metadata

Field	Value
Publication number	US-9410066-B2
Application number	US-201313934179-A
Country	US
Kind code	B2
Filing date	Jul 2, 2013
Priority date	Dec 11, 2008
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

An engineered composition for reducing lost circulation in a well includes a mixture of coarse, medium and optional fine particles, and a blend of long fibers and short fibers. The long fibers are rigid and the short fibers are flexible. The long fibers form a tridimensional mat or net in the lost-circulation pathway that traps the mixture of particles and short flexible fibers to form a mud cake. The mixture of particles and blend of fibers may be added to water based and oil-based drilling fluids. The composition, size, and concentration of each component of the mixture of particles and blend of fibers may be fine-tuned for each application.

First claim

The invention claimed is:

1. A method for reducing lost circulation in a well comprising:
(i) adding to an aqueous drilling fluid a composition comprising:
(1) a mixture of coarse particles having an average particle size between 300 and 1200 μm, medium particles having an average particle size between 20 and 150 μm and optionally fine particles having an average particle size between 5 and 15 μm; and
(2) a blend of long fibers having an average length between 8 and 15 mm, and short fibers having an average length between 1 and 8 mm; and

(ii) circulating the drilling fluid in and out of the well.

2. The method of claim 1 , wherein the particle mixture comprises from 0 to 15 weight percent fine particles, 20 to 40 weight percent medium particles, and 40 to 60 weight percent coarse particles.

3. The method of claim 1 , wherein the particles are selected from the group consisting of alkaline earth carbonates, poly-paraphenyleneterephthalamide, mica, rubber, polyethylene, polypropylene, polystyrene, poly(styrenebutadiene, fly ash, silica, mica, alumina, glass, barite, ceramic, metals and metal oxides, starch and modified starch, hematite, ilmenite, microspheres, glass microspheres, magnesium oxide, gilsonite, sand, and mixtures thereof.

4. The method of claim 1 , wherein the particle mixture comprises 8 to 12 weight percent fine calcium carbonate, 30 to 40 weight percent poly-paraphenyleneterephthalamide, mica or calcium carbonate, and 45 to 60 weight percent coarse calcium carbonate.

5. The method of claim 1 , wherein the fibers are selected from the group consisting of polyvinyl alcohol, polyamide, aramid, para-aramid, polylactic acid, polyglycolic acid, metals, painted metals, polymer-coated metals, hollow metals, hollow painted metals, hollow coated metals, polypropylene, polyethylene, polyester, polyamide, polyolefin, novoloid, phenol-aldehyde, nylon, rayon, extruded mineral wool, carbon, basalt, asbestos, and glass.

6. The method of claim 1 , wherein the weight ratio of long fibers to short fibers is from 1:4 to 4:1.

7. The method of claim 1 , wherein the length ratio of long fibers to short fibers is from 1:1 to 3:1.

8. The method of claim 1 , wherein at least a portion of the fibers is acid soluble.

9. The method of claim 1 , wherein the long fibers comprise water insoluble polyvinyl alcohol and the short fibers comprise water-soluble polyvinyl alcohol.

10. The method of claim 1 , wherein the short fibers comprise a mixture of fibers of two different lengths.

11. The method of claim 1 , wherein the short fibers comprise a mixture of two different lengths of polyvinyl alcohol fibers.

12. The method of claim 1 , wherein the short fibers comprise a mixture of multiple lengths of polyaramid fibers.

13. The method of claim 1 , wherein the particle mixture is added to the drilling fluid at a concentration between 2.85 kg/m 3 and 130 kg/m 3 .

14. The method of claim 1 , wherein the blend of fibers is added to the drilling fluid at a concentration between 14 kg/m 3 and 42 kg/m 3 .

15. The method of claim 1 , wherein at least a portion of the fibers is coated with a material that improves the dispersion of the fibers in the drilling fluid.

16. The method of claim 1 , wherein the long fibers comprise water-insoluble polyvinyl alcohol and the short fibers comprise polyaramid fibers, water soluble polyvinyl alcohol fibers, or inorganic mineral fibers.

17. The method of claim 1 , wherein the long fibers comprise polyaramid fibers or polyvinyl alcohol fibers.

18. The method of claim 1 , wherein the short fibers comprise a mixture of two different lengths or a mixture of multiple lengths of fibers.

19. The method of claim 1 , wherein both the long fibers and the short fibers comprise polyvinyl alcohol fibers.

20. The method of claim 1 , wherein at least one fiber type has a Young's modulus higher than 20 GPa.

Assignees

• Schlumberger Technology Corp

Inventors

• Ghassemzadeh Jaleh

Classifications

• C09K8/516

  characterised by their form or by the form of their components, e.g. encapsulated material · CPC title

• C09K8/035 Primary

  Organic additives · CPC title

• C09K2208/08

  Fiber-containing well treatment fluids · CPC title

• C09K8/506

  containing organic compounds · CPC title

• C09K8/5045

  containing inorganic compounds · CPC title