Downhole tool

Patent metadata

Field	Value
Publication number	US-11142678-B2
Application number	US-201917258616-A
Country	US
Kind code	B2
Filing date	Jun 6, 2019
Priority date	Jul 12, 2018
Publication date	Oct 12, 2021
Grant date	Oct 12, 2021

Abstract

A downhole tool that has a high initial compressive strength, can maintain compressive strength for a certain period of time, and is rapidly degradable after use. The downhole tool is formed from a degradable resin composition containing a polyamide resin and a carboxylic acid anhydride, and the carboxylic acid anhydride is a compound satisfying the following melting point condition:melting point of polyamide resin≤5% weight reduction temperature of carboxylic acid anhydride.

First claim

The invention claimed is:

1. A downhole tool formed from a degradable resin composition comprising a polyamide resin and a carboxylic acid anhydride,
wherein the carboxylic acid anhydride is a compound satisfying the following condition:
melting point of polyamide resin≤5% weight reduction temperature of carboxylic acid anhydride.

2. The downhole tool according to claim 1 , wherein a content of the carboxylic acid anhydride in the degradable resin composition is 0.1 mass % or greater and 10 mass % or less of the polyamide resin.

3. The downhole tool according to claim 1 , wherein the carboxylic acid anhydride is at least one selected from the group consisting of 3,3′,4,4′-biphenyl tetracarboxylic acid dianhydride; 1,2,4,5-benzene tetracarboxylic acid dianhydride; 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride; 1,2,3,4-butane tetracarboxylic acid dianhydride;
and cyclobutane tetracarboxylic acid dianhydride.

4. The downhole tool according to claim 1 , wherein the degradable resin composition further comprises a reinforcing material.

5. The downhole tool according to claim 1 , wherein the polyamide resin is a polyamide-imide, a semi-aromatic polyamide, or a combination thereof.

6. The downhole tool according to claim 1 ,
wherein the downhole tool is composed of a plurality of downhole tool members; and
a volume ratio of at least one of the plurality of downhole tool members, which is formed from the degradable resin composition, to the downhole tool is 50% or greater of the entire downhole tool.

7. The downhole tool according to claim 6 , which is a plug.

Assignees

• Kureha Corp

Inventors

• Kobayashi Fuminori
• Saijo Hikaru

Classifications

• C08K7/14

  Glass · CPC title

• E21B2200/08

  Down-hole devices using materials which decompose under well-bore conditions · CPC title

• E21B33/134

  Bridging plugs · CPC title

• C08K5/0033 Primary

  Additives activating the degradation of the macromolecular compound · CPC title

• E21B43/16

  Enhanced recovery methods for obtaining hydrocarbons · CPC title