China University of Petroleum

Xiaoqing Li

Guancheng Jiang

Lili Yang

Yinbo He

Tengfei Dong

Wuquan Li

Kai Wang

Li Li Zhao

Jingping Liu

Xianbin Huang

Xuwu Luo

Bin Tan

Rongchao Cheng

Jianguo Zhang

He Shi

Tie Geng

Haiyang Liu

Jingen Deng

Jiansheng Luo

Chunlin Xie

Dongmin Jia

The invention relates to the technical field of oil and gas drilling, and discloses an amphiphilic block polymer ultralow-permeability agent and an intelligent temporary plugging type water-based drilling fluid. The ultralow-permeability agent contains a structural unit provided by styryl hydrophobic monomer, maleic anhydride and acrylamide; the drilling fluid contains two or more of water, sodium bentonite, Pac-Lv, the ultralow-permeability agent, calcium carbonate, one-way plugging agent, white asphalt and barite which are stored in a mixed manner or independently stored. When the amphiphilic block polymer provided by the invention is used as the ultralow-permeability agent of the intelligent temporary plugging type water-based drilling fluid, the self-adaptive characteristic is realized; according to the amphiphilic block polymer, temporary plugging layer gaps formed in pore and throats by plugging materials in drilling fluid can be fully filled under the condition that the sizes and the distribution of the pore and throats of reservoirs are not required to be clear, so that the permeability of temporary plugging layer is greatly reduced, ultralow-permeability is realized, and the amphiphilic block polymer is weak in tackifying effect, has gel-improving effect and can improve the rheological property of the drilling fluid.

Amphiphilic block polymer ultralow-permeability agent and intelligent temporary plugging type water-based drilling fluid

The invention discloses a calcium-resistant zwitterionic polymer, a preparation method and an application thereof, and a water-based drilling fluid containing the polymer as a dispersing agent, wherein the polymer contains a structural unit A, a structural unit B and a structural unit C, and the structural unit A is at least one selected from the group consisting of structural units with a structure shown in a formula (11), a structure shown in a formula (12) and a structure shown in a formula (13); the structural unit B is a structural unit with a structure shown in a formula (2); the structural unit C is at least one selected from the group consisting of structural units having a structure represented by formula (31) and a structure represented by formula (32); the weight-average molecular weight of the polymer is 350,000 to 600,000. 

Calcium-resistant zwitterionic polymer, preparation method and application thereof, and water-based drilling fluid containing polymer as dispersant

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Beijing, China

Xiaoqing Li