Processing

Please wait...

Settings

Settings

Goto Application

1. WO2021066814 - SETTABLE, REMOVABLE, AND REUSABLE LOST CIRCULATION FLUIDS

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

CLAIMS

What is claimed is:

1. A method of drilling a borehole in a subterranean formation from the Earth’s surface, comprising:

mixing, at the surface, a base fluid, a polyvalent cation reactive polymer, and a delayed source of polyvalent cation so as to form a treatment fluid;

placing the treatment fluid in the subterranean formation so as to form a solid plug comprising the polyvalent cation reactive polymer crosslinked with the polyvalent cation;

contacting the solid plug with a breaker so as to transform the solid plug into a reclaimed treatment fluid; and

removing the reclaimed treatment fluid from the subterranean formation.

2. The method of claim 1, wherein the method further comprises repeating the placing, contacting, and removing with the reclaimed treatment fluid as the treatment fluid.

3. The method of claim 2, further comprising mixing, at the surface, an additional amount of one or more of the delayed source of polyvalent cation, the polyvalent cation reactive polymer, and the base fluid into the reclaimed treatment fluid.

4. The method of claim 1, wherein breaker comprises a chelator selected from the group consisting of citrate, N,N-dicarboxymethyl glutamic acid tretrasodium salt (GLDA), ethylenediaminetretraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA), trans-1,2-cyclohexanediamine-n,n,n',n'-tetraacetic acid (CyDTA), ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA), Triethylenetetramine-N,N,N',N",N"',N"'-hexaacetic acid (TTHA), _ Iminodiacetic acid (IDA), 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA), and combinations thereof.

5. The method of claim 1, wherein the polyvalent cation is a polyvalent metal cation.

6. The method of claim 1, wherein the polyvalent cation reactive polymer is selected from the group consisting of carrageenan, pectin, algin, alginate, carboxymethylcellulose, carboxymethyl hydroxypropyl guar, carboxymethyl hydroxyethyyl guar, xanthan, diutan, carboxymethylhydroxylcellulose, carboxymethyl starch, partially hydrolyzed polyacrylamide, polyacrylic acid, polyacrylate derivatives thereof, and combinations thereof

7. The method of claim 1, further comprising converting an acid precursor to the acid at a temperature of the subterranean formation so as to react with the polyvalent cation source to produce the polyvalent cation.

8. The method of claim 7, wherein the treatment fluid further comprises exothermic reaction additives, and wherein the placing comprises allowing the exothermic reaction additives to react to provide the temperature.

9. The method of claim 1, further comprising delaying a release of the delayed source of polyvalent cation by encapsulating the delayed source of polyvalent cation with a degradable coating.

10. The method of claim 9, wherein the coating comprises a coating material selected from the group consisting of resins, lipids, acrylics, polyvinylidene chloride (PVdC), urea-formaldedye, and combinations thereof.

11. The method of claim 1, wherein the chelator comprises EDTA, the polyvalent cation reactive polymer comprises alginate, the polyvalent cation source comprises calcium carbonate, the treatment fluid further comprises a formic acid ester and/or lactic acid ester.

12. The method of claim 11, further comprising:

suspending rotation of a drill bit during the mixing, placing, contacting, and removing; and

mixing, at the surface, an additional amount of one or more of the delayed source of polyvalent cation, the polyvalent cation reactive polymer, and the base fluid into the reclaimed treatment fluid.

13. A system for drilling a borehole in a subterranean formation from the Earth’s surface, comprising:

a treatment fluid, at the surface, comprising a polyvalent cation reactive polymer, and a delayed source of polyvalent cation, wherein the treatment fluid is settable in the formation to form a solid plug comprising the polyvalent cation reactive polymer and the polyvalent cation; and

a breaker, separate from the treatment fluid at the surface, capable of liquefying the solid plug in the subterranean formation.

14. The system of claim 13, wherein the breaker comprises a chelator selected from the group consisting of citrate, N,N-dicarboxymethyl glutamic acid tretrasodium salt (GLDA), ethylenediaminetretraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA), trans-1,2-cyclohexanediamine-n,n,n',n'-tetraacetic acid (CyDTA), ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA), Triethylenetetramine-N,N,N',N",N"',N"'-hexaacetic acid (TTHA), iminodiacetic acid (IDA), 1,2-bis(o- aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA), and combinations thereof.

15. The system of claim 13, wherein the delayed source of polyvalent cation comprises a salt of a polyvalent metal cation.

16. The system of claim 13, wherein the polyvalent cation reactive polymer is selected from the group consisting of carrageenan , pectin , algin, alginate, carboxymethylcellulose, carboxymethyl hydroxypropyl guar, carboxymethyl hydroxyethyyl guar, xanthan, diutan, carboxymethylhydroxylcellulose, carboxymethyl starch, partially hydrolyzed polyacrylamide, polyacrylic acid, polyacrylate derivatives thereof, and combinations thereof.

17. The system of claim 13, wherein the treatment fluid comprises an acid precursor convertible to the acid at a temperature of the subterranean formation so as to react with the polyvalent cation source to form the polyvalent cation.

18. The system of claim 13, wherein the delayed source of polyvalent cation is encapsulated by a degradable coating providing delayed release of the delayed source of polyvalent cation.

19. The system of claim 13, wherein the chelator comprise EDTA, the polyvalent cation reactive polymer comprises alginate, the polyvalent cation source comprises calcium carbonate, and the treatment fluid comprise a formic acid source and/or lactic acid source.

20. The system of claim 13, further comprising:

a container capable of dispensing the treatment fluid; and

a tubular disposed in the borehole and in fluid communication with the container, and comprising an end in proximity to the formation.