Polymer system for fluid loss control

Patent metadata

Field	Value
Publication number	US-2019256759-A1
Application number	US-201916402639-A
Country	US
Kind code	A1
Filing date	May 3, 2019
Priority date	Aug 4, 2016
Publication date	Aug 22, 2019
Grant date	—

Abstract

A combination of three polymers including a crosslinked acrylamide-TBAS copolymers in inverse emulsion form, N-vinyl pyrrolidone-acrylamide-TBAS terpolymer, and crosslinked N-vinyl pyrrolidone-acrylamide-TBAS acts as high temperature, high pressure fluid loss control additives for water-based drilling fluids systems. The combination is particularly useful for high salt, high density drilling fluids, and high temperature applications.

First claim

What is claimed is:

1 . A method for controlling fluid loss while drilling a wellbore comprising
using a water-based drilling fluid comprising a first polymer comprising a acrylamide-NVP-2-acrylamide-2-methylpropanesulfonic acid terpolymer comprising
an acrylamide monomer at 30-80%;
a 2-acrylamide-2-methylpropanesulfonic acid monomer at 10-50%; and
a NVP monomer at 5-30%;
a second polymer comprising a crosslinked acrylamide-NVP-2-acrylamide-2-methylpropanesulfonic acid terpolymer comprising
an acrylamide monomer at 30-80%;
a 2-acrylamide-2-methylpropanesulfonic acid monomer 10-50%;
an NVP monomer at 5-20%; and
a crosslinking monomer at 0.05%-0.5%; and
a third polymer comprising a crosslinked acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer in inverse emulsion comprising
an acrylamide monomer at 30-80%;
a 2-acrylamide-2-methylpropanesulfonic acid monomer at 20-70%; and
a crosslinking monomer at 0.1-1%.

2 . The method of claim 1 wherein the first polymer comprises an acrylamide-NVP-2-acrylamide-2-methylpropanesulfonic acid terpolymer comprising
an acrylamide monomer at 40-60%;
a 2-acrylamide-2-methylpropanesulfonic acid monomer at 25-40%; and
a NVP monomer at 10-20%.

3 . The method of claim 1 wherein the second polymer comprises a crosslinked acrylamide-NVP-2-acrylamide-2-methylpropanesulfonic acid terpolymer comprising
an acrylamide monomer at 40-60%,
a 2-acrylamide-2-methylpropanesulfonic acid monomer at 25-40%;
an NVP monomer at 10-20%; and
a crosslinking monomer at 0.1-0.3%.

4 . The method of claim 1 wherein the third polymer comprises a crosslinked acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer in inverse emulsion comprising
an acrylamide monomer at 40-60%;
a 2-acrylamide-2-methylpropanesulfonic acid monomer at 40-50%; and
a crosslinking monomer at 0.3-0.6%.

5 . The method of claim 1 wherein the water-based drilling fluid comprises
a first polymer comprising an acrylamide-NVP-2-acrylamide-2-methylpropanesulfonic acid terpolymer comprising
an acrylamide monomer at 40-60%;
a 2-acrylamide-2-methylpropanesulfonic acid monomer at 25-40%; and
a NVP monomer at 10-20%;

a second polymer comprising a crosslinked acrylamide-NVP-2-acrylamide-2-methylpropanesulfonic acid terpolymer comprising
an acrylamide monomer at 40-60%;
a 2-acrylamide-2-methylpropanesulfonic acid monomer at 25-40%;
an NVP monomer at 10-20%; and
a crosslinking monomer at 0.1-0.3%; and

a third polymer comprising a crosslinked acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer in inverse emulsion comprising
an acrylamide monomer at 40-60%;
a 2-acrylamide-2-methylpropanesulfonic acid monomer at 40-50%; and
a crosslinking monomer at 0.3-0.6%.

6 . The method of claim 1 wherein the water-based drilling fluid comprises 1-4 ppb of the first polymer, 2-6 ppb of the second polymer, and 1-4 ppb of the third polymer.

7 . The method of claim 1 wherein the water-based drilling fluid comprises 1-4 ppb of the first polymer A, 1-4 ppb of the second polymer, and 1-4 ppb of the third polymer.

8 . The method of claim 1 wherein the water-based drilling fluid comprises 1-4 ppb of the first polymer, 2-4 ppb of the second polymer, and 2-4 ppb of the third polymer.

Assignees

• Cnpc Usa Corp

Inventors

• Lu Meng
• Huang Ping
• Wan Wei

Classifications

• C09K8/508

  macromolecular compounds {(C09K8/512 takes precedence)} · CPC title

• C09K8/512

  containing cross-linking agents · CPC title

• C09K8/12 Primary

  containing synthetic organic macromolecular compounds or their precursors · CPC title

• C08L33/26

  Homopolymers or copolymers of acrylamide or methacrylamide · CPC title

• C09K8/035

  Organic additives · CPC title