Polyurethane cementing wiper plugs

Patent metadata

Field	Value
Publication number	US-11261283-B2
Application number	US-201916400400-A
Country	US
Kind code	B2
Filing date	May 1, 2019
Priority date	May 1, 2019
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

A method for operation in wellbore, the method comprises: pumping a fluid barrier into a wellbore through a tubular, the fluid barrier being operable to separate a cement slurry from a second fluid; the fluid barrier comprising a polyurethane member derived from a polyurethane forming composition comprising a para-phenylene diisocyanate terminated polycarbonate prepolymer and an aromatic diol.

First claim

What is claimed is:

1. A method for operation in wellbore, the method comprising:
pumping a fluid barrier into a wellbore through a tubular, the fluid barrier being operable to separate a cement slurry from a second fluid; the fluid barrier comprising a polyurethane member derived from a polyurethane forming composition comprising: 100 parts by weight of a para-phenylene diisocyanate terminated polycarbonate prepolymer and 1 to 20 parts by weight of an aromatic diol,
wherein the para-phenylene diisocyanate terminated polycarbonate prepolymer has an isocyanate content of about 1 to about 5 wt % and comprises less than 1.0% by weight of 4,4′-diisocyanato diphenylmethane monomer, each based on the total weight of the para-phenylene diisocyanate terminated polycarbonate prepolymer,
the aromatic diol comprises hydroquinone bis (beta hydroxyethyl) ether, and
the polyurethane forming composition further comprises a chain extender which is a polycarbonate polyol; a crosslinking agent; and a colorant,
wherein a sample of the polyurethane member having a thickness of 0.09 inch has a weight loss of less than about 15 wt %, based on the total weight of the sample when tested in accordance with ASTM D5963-04 (2015); and
the polyurethane member has improved chemical resistance in a basic fluid at an elevated temperature of about 300° F. to about 350° C. as compared to a reference polyurethane member derived from a polyester polyurethane prepolymer or a reference polyurethane member cured with an aromatic diamine.

2. The method of claim 1 , wherein the colorant is a polyol bounding colorant.

3. The method of claim 1 , wherein the polyurethane forming composition comprises:
100 parts by weight of the para-phenylene diisocyanate terminated polycarbonate prepolymer;
1 to 20 parts by weight of the aromatic diol;
5 to 10 parts by weight of the chain extender;
0.1 to 1 part by weight of the crosslinking agent; and
0.01 to 0.1 part by weight of the colorant.

4. The method of claim 1 , wherein the para-phenylene diisocyanate terminated polycarbonate prepolymer has isocyanate groups, and the aromatic diol, the chain extender, the crosslinking agent, and the colorant have active hydrogen groups, and the equivalent ratio of the isocyanate groups relative to the sum of the active hydrogen groups is about 1 to about 1.2.

5. The method of claim 1 , wherein the chain extender is a polycarbonate polyol having a hydroxyl value of about 50 to about 60, as measured in accordance with HS K 1557 B; the colorant is a polyol bounding colorant, and the crosslinking agent is trimethylolpropane.

6. The method of claim 1 , wherein the tubular is a drill pipe, a liner or a casing.

7. The method of claim 1 , wherein the second fluid is a drilling fluid or a completion fluid.

8. The method of claim 1 , wherein the cement slurry is injected after the fluid barrier is pumped into the wellbore through the tubular.

9. The method of claim 1 , further comprising pumping a second fluid barrier into the wellbore through the tubular after the cement slurry is injected to separate the cement slurry from a third fluid.

10. The method of claim 9 , wherein the third fluid is a drilling fluid or a completion fluid.

11. The method of claim 10 , wherein the fluid barrier further comprises a cement pump downhole plug engaged with the wiper plug.

12. The method of claim 1 , wherein the fluid barrier comprises a wiper plug having a core and the polyurethane member disposed on the core.

13. The method of claim 1 , wherein the polyurethane member has improved chemical resistance in a basic fluid at an elevated temperature of about 300° F. to about 350° C. as compared to a reference polyurethane member derived from a polyether polyurethane prepolymer.

14. The method of claim 1 , wherein the polyurethane member is stable in a basic fluid having a pH of greater than about 9 at about 300° F. to about 350° C.

Assignees

• Duan Ping
• Sadana Anil
• Baker Hughes Oilfield Operations Llc

Inventors

• Duan Ping
• Sadana Anil

Classifications

• C08G18/44

  Polycarbonates · CPC title

• C08G18/4263

  containing carboxylic acid groups · CPC title

• C08G18/3243

  containing two or more aromatic rings · CPC title

• C08G18/3215

  containing aromatic groups or benzoquinone groups · CPC title

• C08G18/3206

  aliphatic · CPC title