China Petroleum Chemical Corporation

Sinopec Research Institute of Petroleum Engineering

China Petroleum & Chemical Corporation Exploration & Production Research Institute

Exploration & Production Research Insitute, Sinopec

China Petro-chemical Corporation Shengli Petroleum Administrative Bureau

Changming Su

Jiafen Li

Jing Li

Lin Wang

Sheng Shuang Li

Weiping Xu

Xiaohua Yang

Peizhi Yu

Caixuan Guo

Yusheng Ma

Xianguang Wang

Xiaolin Qian

Rusheng Zhang

Zhifa Wang

Jianzheng Su

Liwei Ren

Qiulian Long

Guichuan Liu

Bingzhong Shi

Rushan Liu

Suobing Zhang

Zengchen Guan

Xiushan Liu

Danian Zhang

Baoyu Guo

Chenggang Zheng

Yingchun Cui

Mengyun Zhao

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&#x2212;x&#x2212;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. 

Cationic copolymer and use thereof in lost circulation additive

A copolymer and preparation method and application thereof are disclosed. The copolymer is random copolymer obtained from monomers consisting of acrylamide, acrylic acid, alkenyl sulfonate, 2-acrylamido-dodecyl sulfonate, p-styrene sulfonate or isoprene sulfonate and so on. The copolymer of present invention can be used as fluid loss additive and has good fluid loss properties, which would not make the drilling fluid thicken at high temperature of 200&#xb0; C. and high salt conditions of saturated brine. It has a medium-pressure fluid loss after aging and rolling for 16 h at high temperature of 200&#xb0; C., as measured in accordance with the American Petroleum Institute Standard Test at room temperature, and has good properties of high temperature-resisting and salt-resisting.

Copolymer and preparation method and application thereof

An electropositive and water-based production well treating fluid system exhibits electropositivity by using a cationic viscosifier meanwhile matched with a cationic fluid loss additive and, optionally, contains a mud-building agent, an electrical stabilizing agent, a colloid-stabilizing agent, lubricant, an oil layer protective agent and/or a weighting agent. The electropositive production well treating fluid can beffer solve the contradiction of technical requirements between 'treating fluid stability' and 'bore hole stability', and features a strong ability to inhibit the dispersion of clay, a good effect of protecting oil-gas reservoirs, fast drilling speeds, regular shape of bore holes and good resistance to salt.

Electropositive production well treating fluid and method of preparing the same

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Beijing, China

Changming Su