China University of Petroleum

Jienian Yan

Guancheng Jiang

Yinbo He

Lili Yang

Fan Liu

Guangchang Ma

Haifang Sun

Li Li Zhao

Deli Gao

Chunyao Peng

Xianmin Zhang

Xianzhu Wu

Liexiang Han

Gang Qu

Junbin Chen

Wei Ou'Yang

Yong Qin

Yuxiu An

Yawei Shi

He Shi

Qingying Ge

The present invention relates to the well drilling field in petrochemical industry, and discloses a drilling fluid additive composition comprising a nano-plugging agent, a bionic wall bracing agent, a bionic shale inhibitor, an emulsifier, and an amphiphobic wettability reversal agent, wherein, the nano-plugging agent is modified silicon dioxide nano-particle, and its modifying group includes a modifying copolymer chain; the bionic wall bracing agent is carboxymethyl chitosan with a dopamine-derived group grafted on its main chain; the bionic shale inhibitor is composed of structural units of arginine and structural units of lysine; and the amphiphobic wettability reversal agent is a dual-cation fluorocarbon surfactant. The present invention further provides a pseudo oil-based drilling fluid suitable for horizontal shale gas wells containing the above composition. When the water-based drilling fluid contains the drilling fluid additive composition provided in the present invention, the water-based drilling fluid would have high temperature-resistance, high plugging and high inhibition performance, is environment friendly, especially have high density, and is especially suitable for horizontal shale gas well mining.

Drilling fluid additive composition and pseudo oil-based drilling fluid suitable for horizontal shale gas wells

The present invention relates to the well drilling field in petrochemical industry, and discloses a high-density water-based drilling fluid suitable for horizontal shale gas wells comprising a nano-plugging agent, a bionic wall bracing agent, a bionic shale inhibitor, a filler, an emulsifier, and an amphiphobic wettability reversal agent, wherein, the nano-plugging agent is modified silicon dioxide nano-particle, and its modifying group includes a modifying copolymer chain; the bionic wall bracing agent is carboxymethyl chitosan with a dopamine-derived group grafted on its main chain; the bionic shale inhibitor is composed of structural units of arginine and structural units of lysine; the filler consists of calcium carbonate of 1,600-2,500 mesh, calcium carbonate of 1,050-1,500 mesh, and calcium carbonate of 500-1,000 mesh at a weight ratio of 1:0.55-6:0.55-6; and the amphiphobic wettability reversal agent is a dual-cation fluorocarbon surfactant. The drilling fluid provided herein is suitable for use in shale gas mining.

High-density water-based drilling fluid suitable for horizontal shale gas wells

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

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Beijing, China

Jienian Yan