China University of Petroleum

Yuxiu An

Guancheng Jiang

Xi Wang

Yang Xuan

Shuo Zhang

Jinsheng Sun

Yong Qin

Lili Yang

Yinbo He

Fan Liu

Chunyao Peng

Guangchang Ma

Haifang Sun

Yawei Shi

He Shi

Qingying Ge

Jienian Yan

The present invention relates to the petroleum drilling fluid field, and discloses a modified silicon dioxide nano-particle comprising a modifying polymer chain composed of structural units provided by one or more of monomers represented by the following formula (1) and one or more of monomers represented by the following formula (2). The present invention provides a method for preparing modified silicon dioxide nano-particles and a drilling fluid suitable for shale gas wells containing the modified silicon dioxide nano-particles as a plugging agent. When the modified silicon dioxide nano-particles provided in the present invention are used as a plugging agent in a drilling fluid, they will not agglomerate into large-size particles, and can achieve a good plugging effect. 

Modified silicon dioxide nano-particles and preparation method thereof, and drilling fluid suitable for shale gas wells

The present subject matter discloses a reservoir protecting agent composition, consisting of non-fluorescent sulfonated asphalt and a reservoir protecting agent, wherein, the reservoir protecting agent is composed of structural units denoted by the following formula (1), (2), and (3). The present subject matter further provides a drilling fluid that contains the above-mentioned reservoir protecting agent composition for middle permeability reservoirs. The present subject matter further provides an application of the drilling fluid for middle permeability reservoirs in well drilling in middle permeability reservoirs. The drilling fluid for middle permeability reservoirs disclosed in the present subject matter exhibits favorable rheology property, temperature tolerance property, and anti-collapse and protection performance when it is used in wall drilling in middle permeability reservoirs. 

Reservoir protecting agent composition, drilling fluid for middle permeability reservoirs and use thereof

The present subject matter relates to a preparation method of a wettability reversal agent, comprising: (1) adding an emulsifier into water to prepare a mixed solution of emulsifier; (2) adding compounds represented by formula (1-a), (2-a), (3-a), (4-a), (5-a), and (6-a) to the mixed solution of emulsifier to obtain a pre-emulsion, adding an initiator, and initiating a polymerization reaction. When the wettability reversal agent and reservoir protecting agent composition disclosed in the present subject matter are used in a drilling fluid, they can effectively prevent the permeation of the water phase and oil phase in the drilling fluid into the reservoir, reduce the filter loss of the drilling fluid, and thereby effectively protect the reservoir against damages from the drilling fluid. 

Preparation method of a wettability reversal agent

The present subject matter relates to a reservoir protecting agent composition, consisting of non-fluorescent sulfonated asphalt, micron-sized cellulose, and a reservoir protecting agent, wherein, the reservoir protecting agent is composed of structural units denoted by the following formula (1), formula (2), and formula (3). The present subject matter further provides a broad-spectrum drilling fluid that contains the reservoir protecting agent composition. The present subject matter further provides a use of the broad-spectrum drilling fluid in oil and gas well drilling. When the broad-spectrum drilling fluid provided in the present subject matter is used in oil and gas well drilling in reservoirs with different structures, it exhibits good rheology property, temperature tolerance, and anti-collapse and protection performance. 

Reservoir protecting agent composition and broad-spectrum drilling liquid and use thereof

The present subject matter relates to a protecting agent composition for high/ultra-high permeability reservoirs, consisting of a protecting agent and a filler, wherein, the filler comprises calcium carbonate of 600-1,000 mesh, calcium carbonate of 300-590 mesh, and calcium carbonate of 50-200 mesh at 1:(1-30):(0-40) weight ratio, and the protecting agent comprises structural units denoted by the following formulae (1), (2), and (3). The present subject matter further provides a drilling fluid containing the above-mentioned composition. The present subject matter further provides a use of the drilling fluid for drilling in high/ultra-high permeability reservoirs. The drilling fluid provided in the present subject matter has advantages including easy use, high environmental friendliness, and outstanding reservoir protection, greatly reduces the damages of drilling fluid to high/ultra-high permeability reservoirs, and brings substantial economic benefits. 

Protecting agent composition for high/ultra-high permeability reservoirs and drilling fluid and use thereof

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Beijing, China

Yuxiu An