Cationic copolymer and use thereof in lost circulation additive

US10266617B2 · kind B2 · utility

Assignees

• CHINA PETROLEUM & CHEMICAL CORPORATION · CN
• CHINA PETROLEUM & CHEMICAL CORPORATION EXPLORATION & PRODUCTION RESEARCH INSTITUTE · CN

Inventors

• Changming Su · Beijing, CN
• Mengyun Zhao · Beijing, CN
• Jianzheng Su · Beijing, CN
• Rusheng Zhang · Pittsburgh, US
• Qiulian Long · Beijing, CN
• Suobing Zhang · Beijing, CN
• Danian Zhang · Beijing, CN
• Chenggang Zheng · Beijing, CN
• Yusheng Ma · Beijing, CN

Key dates

• Filing date: Oct 25, 2013
• Grant date: Apr 23, 2019
• Expiry date: Sep 5, 2034

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F212/26
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A cationic copolymer represented by the following formula (I) has a viscosity average molecular weight in a range from 2 million to 10 million. In the cationic copolymer, the mole fractions of three structural units corresponding to three monomers are as follows: x being in a range from 0.01 to 20%, y being in a range from 0 to 15%, and z=1−x−y. When used in the construction of leaking stoppage in an oil well, a cationic chemical lost circulation additive prepared with the cationic copolymer is mixed with an anionic drilling fluid in a section of the wellbore where lost circulation occurs. Then neutral reaction and cross linking reaction occur, so that the viscosity of the resulting mixture rapidly increases to form a space grid structure. This blocks off the leakage path, and thus effects on efficient leaking stoppage in a short time period.