	US 11,891,563 B2
	pH-sensitive temporary plugging agent, preparation method thereof, and use thereof in exploitation of low-permeability oil reservoir
Huan Yang, Jingzhou (CN); Zhuyang Jiang, Jingzhou (CN); Xiaorong Yu, Jingzhou (CN); Gaoshen Su, Jingzhou (CN); Kailu Wang, Jingzhou (CN); Beibei Zhang, Jingzhou (CN); Yang Li, Jingzhou (CN); and Chang Xiao, Jingzhou (CN)
Assigned to YANGTZE UNIVERSITY, Jingzhou (CN)
Filed by YANGTZE UNIVERSITY, Jingzhou (CN)
Filed on Sep. 8, 2021, as Appl. No. 17/469,669.
Claims priority of application No. 202110405513.0 (CN), filed on Apr. 15, 2021.
Prior Publication US 2022/0333001 A1, Oct. 20, 2022
Int. Cl. C09K 8/035 (2006.01); C09K 8/42 (2006.01); C09K 8/44 (2006.01); C09K 8/514 (2006.01)

CPC C09K 8/426 (2013.01) [C09K 8/035 (2013.01); C09K 8/44 (2013.01); C09K 8/514 (2013.01)]

7 Claims

1. A method for preparing a pH-sensitive temporary plugging agent, comprising:

mixing raw materials to obtain a final mixed solution, the raw materials comprising, in percentages by mass,

3-8% of carboxymethyl chitosan,

0.2-0.7% of gelatin,

0.1-0.6% of an initiator,

5-15% of a toughener, and

a balance of water,

wherein the initiator is a solution of AgNO₃in ammonia water having a concentration of 0.1-0.3 mol/L, and

the toughener is a carboxyl-terminated hyperbranched polyester; and

subjecting the final mixed solution to a crosslinking reaction at 40-60° C. to obtain the pH-sensitive temporary plugging agent.