Degradable polymer composition for use in downhole tools and method of manufacturing

Patent metadata

Field	Value
Publication number	US-2021253773-A1
Application number	US-202016789946-A
Country	US
Kind code	A1
Filing date	Feb 13, 2020
Priority date	Feb 13, 2020
Publication date	Aug 19, 2021
Grant date	—

Abstract

A chemical composition for a degradable polymeric material includes an isocyanate terminated polyester prepolymer, including prepolymer units as a main chain with a plurality of isocynanates at ends of the main chain, and a cross-linking agent. The isocyanate terminated polyester prepolymer has a structural formula as follows:ONC—R″—NH—[—CO—R—R″′-]n-NH—R″—CNO,wherein R″′ is selected from a group consisting of —O— and —CO—O—R′—O—,wherein R, R′ and R″ are an aryl group or alkyl group and wherein n is a number of prepolymer units corresponding to length of the main chain. The composition degrades at a rate and at a delay depending on temperature and the composition for a component of a downhole tool. The composition has strength and elasticity for a component of a downhole tool.

First claim

1 . A chemical composition for a degradable polymeric material, the chemical composition comprising:
an isocyanate terminated polyester prepolymer, being comprised of prepolymer units as a main chain with a plurality of isocynanates at ends of said main chain, said isocyanate terminated polyester prepolymer having a structural formula below:
ONC—R″—NH—[—CO—R—R″′-] n -NH—R″—CNO,

wherein R″′ is selected from a group consisting of —O— and —CO—O—R′—O—,

wherein R is an aryl group or alkyl group,
wherein R′ is an aryl group or alkyl group,
wherein R″ is an aryl group or alkyl group, and
wherein n is a number of prepolymer units corresponding to length of said main chain; and
a cross-linking agent so as to reach fracturing failure between 8 hours and 30 days depending on temperature and salinity, maintain less than 5% weight loss within 2 days and display more than 40% weight loss within 20 days depending on temperature and salinity, and maintain less than 5% hardness loss within 2 days depending on temperature and salinity.

2 . The chemical composition of claim 1 ,
wherein said isocyanates are selected from group consisting of: 2,4-toluene di-isocyanate, 2, 6 toluene di-isocyanate, methylene diphenyl diisocyanate (MDI), para-phenyl diisocyanate (pPDI), and hexamethylene isocyanate (HDI).

3 . The chemical composition of claim 1 ,
wherein said cross-linking agents are selected from a group consisting of: diamine 4,4′ methylene-bis-(o-chloroaniline), dimethyl thio-toluene diamine, diols, polycarbonate polyols, polyester glycol, and triols.

4 . The chemical composition of claim 3 ,
wherein said diols are comprised of butanediol.

5 . The chemical composition of claim 1 ,
wherein said isocyanate terminated polyester prepolymer and said cross-linking agent reach fracturing failure in 0.3% KCl at 90° C. within 15 days, in 1.0% KCl at 93° C. within 4 days, and in 0.3% KCl at 120° C. within 22 hours.

6 . The chemical composition of claim 1 ,
wherein said isocyanate terminated polyester prepolymer and said cross-linking agent maintain less than 5% weight loss in 0.3% KCl at 90° C. within 2 days, and wherein said isocyanate terminated polyester prepolymer and said cross-linking agent display more than 40% weight change in 0.3% KCl at 90° C. within 20 days.

7 . The chemical composition of claim 1 ,
wherein said isocyanate terminated polyester prepolymer and said cross-linking agent with a catalyst maintain less than 5% weight loss in 0.3% KCl at 90° C. within 2 days, and wherein said isocyanate terminated polyester prepolymer and said cross-linking agent delay more than 60% weight change in 0.3% KCl with said catalyst at 90° C. within 20 days.

8 . The chemical composition of claim 7 ,
wherein said catalyst is selected from a group consisting of: dibutyltin dilaurate, dimethylbis(1-oxoneodecyl), octyltin dithioglycolate, and dioctyltin mercaptide.

9 . The chemical composition of claim 7 ,
wherein said isocyanate terminated polyester prepolymer and said cross-linking agent maintain less than 5% hardness loss in 0.3% KCl at 90° C. within 2 days.

10 . A chemical composition for a degradable polymeric material, the chemical composition comprising:
an isocyanate terminated polyester prepolymer, being comprised of prepolymer units as a main chain with a plurality of isocynanates at ends of said main chain, said isocyanate terminated polyester prepolymer having a structural formula below:
ONC—R″—NH—[—CO—R—R″′-] n -NH—R″—CNO,

wherein R″′ is selected from a group consisting of —O— and —CO—O—R′—O—,

wherein R is an aryl group or alkyl group,
wherein R′ is an aryl group or alkyl group,
wherein R″ is an aryl group or alkyl group, and
wherein n is a number of prepolymer units corresponding to length of said main chain; and
a cross-linking agent so as to have an average tensile strength over 5000psi at room temperature depending on Shore A, an average elongation break over 400% at room temperature depending on Shore A, an average tensile strength less than 1300 psi with 75 Shore A at 90° C., an average elongation break over 300% at 90° C. depending on Shore A, and hold a 10000 psi differential over 24 hours.

11 . The chemical composition of claim 10 ,
wherein said isocyanate terminated polyester prepolymer and said cross-linking agent have an average tensile strength over 4500psi with 75 Shore A at room temperature, an average tensile strength over 7000 psi with 90 Shore A at room temperature, an average elongation break over 500% with 75 Shore A at room temperature, and an average elongation break over 400% with 90 Shore A at room temperature.

12 . The chemical composition of claim 10 ,
wherein said isocyanate terminated polyester prepolymer and said cross-linking agent an average elongation break over 500% with 75 Shore A at 90° C. and an average elongation break over 300% with 90 Shore A at 90° C.

13 . A method for formation of a degradable polymeric material, the method comprising the steps of:
vacuuming a prepolymer unit of claim 1 ; vacuuming a cross-linking agent; mixing said prepolymer unit and said cross-linking agent so as to form a mixture; and molding said mixture so as to form a cured polymer as a component.

14 . The method for formation, according to claim 13 ,
wherein the step of mixing said prepolymer unit, said cross-linking agent, and said catalyst is by centrifuge.

15 . The method for formation, according to claim 13 ,
wherein the step of mixing said prepolymer unit, said cross-linking agent, and said catalyst is under vacuum.

16 . The method for formation, according to claim 13 ,
wherein the step of mixing said prepolymer unit, said cross-linking agent, and said catalyst further comprises adding a filler.

17 . The method for formation, according to claim 16 ,
wherein said filler is selected from a group consisting of carbon blacks, silica, nanographene, nanoclays, nanofibers, and nanotubes.

18 . A method for removal, the method comprising the steps of:
forming a chemical composition according to claim 1 into a component; installing said component in an assembly; dissolving said component in a solution with salinity less than 0.3% at 90° C. into a degraded component; and collapsing said assembly so as to remove said assembly and said degraded component.

19 . The method for removal, according to claim 18 ,
wherein the step of dissolving said component further comprises a step of: adding a catalyst, and wherein said catalyst is selected from a group consisting of: an acid and a base.

20 . The method for removal, according to claim 19 , further comprising: dissolving said degraded component completely.

Assignees

• Cnpc Usa Corp
• Beijing Huamei Inc

Inventors

• Ren Jiaxiang
• Cheng Peng
• Wang Xu

Classifications

• C08G2230/00

  Compositions for preparing biodegradable polymers · CPC title

• C08G18/10 Primary

  Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step · CPC title

• C08G18/3243

  containing two or more aromatic rings · CPC title

• C08G18/3857

  having nitrogen in addition to sulfur · CPC title

• C08G18/7621

  being toluene diisocyanate including isomer mixtures · CPC title