Casing flush fluid, recyclable cleanout fluids, and applications thereof

Patent metadata

Field	Value
Publication number	US-2016290104-A1
Application number	US-201615084539-A
Country	US
Kind code	A1
Filing date	Mar 30, 2016
Priority date	Mar 30, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

A method of removing residual proppant from a bottom of a casing after a fracturing operation comprises: circulating a casing flush fluid comprising a carrier and a superabsorbent polymer in the casing; and transporting the residual proppant from the bottom of the casing to a fracture created by a hydraulic fracturing operation. A method for cleaning a wellbore comprises: introducing a cleanout fluid through a conduit inserted into the wellbore, the cleanout fluid comprising a carrier fluid and a superabsorbent polymer; and receiving a returning fluid comprising debris at the surface of the wellbore from an annular space between the conduit and a wall of the wellbore.

First claim

What is claimed is:

1 . A method of removing residual proppant in a horizontal or deviated wellbore from a bottom surface of a casing or tubing string after a fracturing operation, the method comprises:
circulating a casing flush fluid comprising a carrier and a superabsorbent polymer in the casing or tubing; and transporting the residual proppant from the bottom surface of the casing or tubing to a fracture created by a hydraulic fracturing operation.

2 . The method of claim 1 , further comprising breaking the superabsorbent polymer after the residual proppant is transported from the bottom surface of the casing to the fracture.

3 . The method of claim 1 , further comprising setting up a bridge plug after the casing is treated with the casing flush fluid.

4 . The method of claim 1 , wherein the carrier comprises water or brine; and
the superabsorbent polymer comprises repeating units derived from an acrylic acid or a salt thereof, an acrylate, an acrylamide, a vinylpyrrolidone, a vinyl acetate, a vinyl alcohol, a 2-acrylamide-2-methylpropanesulfonic acid, a derivative thereof, or a combination thereof; and the superabsorbent polymer comprises a plurality of crosslinks.

5 . The method of claim 4 , wherein the crosslinks of the superabsorbent polymer are formed prior to combining the superabsorbent polymer with the carrier.

6 . The method of claim 1 , wherein the casing flush fluid comprises about 30 to about 60 pounds of the superabsorbent polymer per one thousand gallons of the casing flush fluid.

7 . The method of claim 1 , wherein the casing flush fluid further comprises a gas constituent and the sum of the volumes of the gas constituent and the superabsorbent polymer is greater than about 50%, based on the total volume of the casing flush fluid.

8 . The method of claim 1 , wherein the casing flush fluid further comprises about 2 pounds to about 25 pounds of a polysaccharide per one thousand gallons of the casing flush fluid.

9 . A method for cleaning out a wellbore, the method comprising:
introducing a cleanout fluid through a conduit inserted into the wellbore, the cleanout fluid comprising a carrier fluid and a superabsorbent polymer present in amount effective to suspend and carry debris in the wellbore to a surface of the wellbore; and receiving a returning fluid comprising debris at the surface of the wellbore from an annular space between the conduit and a wall of the wellbore.

10 . The method of claim 9 , wherein the conduit comprises a drilling string, casing string, tubing string, joined tubing, or coiled tubing.

11 . The method of claim 9 , further comprising:
adding water to the returning fluid to provide a thinned out composition comprising a slurry of hydrated particles of the superabsorbent polymer and debris settled out of the thinned out composition; separating the debris from the slurry; and filtering the slurry through a mesh filter to provide recycled hydrated particles of the superabsorbent polymer, the mesh filter having a mesh size smaller than a predetermined average size of the hydrated particles of the superabsorbent polymer.

12 . The method of claim 11 , further comprising
combining the recycled hydrated particles of the superabsorbent polymer with a carrier and optionally with an unhydrated superabsorbent polymer to provide a treatment fluid, and introducing the treatment fluid into a subterranean formation.

13 . The method of claim 9 , wherein the cleanout fluid is a foamed fluid further comprising a foaming agent and a gas constituent.

14 . The method of claim 13 , wherein the gas constituent is nitrogen, carbon dioxide, air, argon, helium, natural gas, or a combination comprising at least one of the foregoing.

15 . The method of claim 13 , wherein the sum of the volumes of the gas constituent and the superabsorbent polymer is greater than about 50%, based on the total volume of the foamed cleanout fluid.

16 . The method of claim 9 , wherein
the carrier comprises water or brine; and the superabsorbent polymer comprises repeating units derived from an acrylic acid or a salt thereof, an acrylate, an acrylamide, a vinylpyrrolidone, a vinyl acetate, a vinyl alcohol, a 2-acrylamide-2-methylpropanesulfonic acid, a derivative thereof, or a combination thereof; and the superabsorbent polymer comprises a plurality of crosslinks.

17 . The method of claim 16 , wherein the crosslinks of the superabsorbent polymer are formed prior to combining the superabsorbent polymer with the carrier.

18 . The method of claim 9 , wherein the cleanout fluid comprises about 30 to about 60 pounds of the superabsorbent polymer per one thousand gallons of the cleanout fluid.

19 . The method of claim 9 , wherein the cleanout fluid further comprises about 2 pounds to about 25 pounds of a polysaccharide per one thousand gallons of the cleanout fluid.

20 . A method of recycling a superabsorbent polymer, the method comprising:
adding water to a fluid containing hydrated particles of the superabsorbent polymer and a plurality of suspended particles that are not the same as the hydrated particles of the superabsorbent polymer; precipitating the suspended particles to form precipitated particles and a slurry comprising hydrated particles of the superabsorbent polymer; removing the precipitated particles; and filtering the slurry through a mesh filter to provide recycled hydrated particles of the superabsorbent polymer; the mesh filter having a mesh size smaller than a predetermined average size of the hydrated particles of the superabsorbent polymer.

21 . The method of claim 19 , wherein the suspended particles have at least a size or a density greater than the hydrated particles of the superabsorbent polymer.

22 . The method of claim 19 , further comprising
combining the recycled hydrated particles of the superabsorbent polymer with a carrier to provide a treatment fluid, and introducing the treatment fluid into a subterranean formation.

23 . The method of claim 19 , further comprising
combining the recycled hydrated particles of the superabsorbent polymer with an unhydrated superabsorbent polymer to provide a treatment fluid; and introducing the treatment fluid into a subterranean formation.

Assignees

• Nelson Scott G
• Li Leiming
• Sun Hong
• Zhou Jia
• Baker Hughes Inc

Inventors

• Nelson Scott G
• Li Leiming
• Sun Hong
• Zhou Jia

Classifications

• C09K8/62

  Compositions for forming crevices or fractures · CPC title

• C09K8/52

  Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning · CPC title

• C09K8/685

  containing cross-linking agents · CPC title

• E21B43/267 Primary

  reinforcing fractures by propping · CPC title

• C09K8/035

  Organic additives · CPC title