Southwest Petroleum University

Ruolan Wang

Gang Xie

Yang Bai

Jinjun Huang

Qian Zhou

Linlin Zhang

Disclosed are a strong salt-resistant self-degradation plugging agent for water-based drilling fluid and a preparation method therefor. The preparation method includes: modifying unsaturated polyhydroxyalkanoate by using 2-acrylamide-2-methylpropanesulfonic acid to prepare modified polyhydroxyalkanoate; modifying lignin by using an ammonium halide salt to prepare quaternized lignin; and melting and blending the quaternized lignin and the modified polyhydroxyalkanoate to obtain the strong salt-resistant self-degradation plugging agent for water-based drilling fluid. The preparation method is mature and reliable, and is suitable for industrial production. The plugging agent has strong salt resistance and good stability, and has a degradation rate less than 15% within 7 days, which can effectively plug micron-sized fractures in shale formations. Meanwhile, the plugging agent may be directly added to the water-based drilling fluid, and has little effect on the rheology. With addition of the plugging agent, the high-temperature and high-pressure filtration loss of the drilling fluid is significantly reduced.

Strong salt-resistant self-degradation plugging agent for water-based drilling fluid and preparation method therefor

The invention discloses an organic-inorganic nanocomposite gel sealing agent and oil-based drilling fluid. The sealing agent used for the oil-based drilling fluid is organic-inorganic nanocomposite gel, and the synthetic raw materials of the organic-inorganic nanocomposite gel includes molybdenum disulfide, 2-ethyl acrylic acid, N, N-dimethylacrylamide and N,N-methylene bisacrylamide; the drilling fluid includes the organic-inorganic nanocomposite gel provided by the invention. The organic-inorganic nanocomposite gel is used as a nano sealing agent, the particle size distribution of the organic-inorganic nanocomposite gel is 50-200 nm, the organic-inorganic nanocomposite gel can effectively prevent drilling fluid filtrate from intruding into stratums and prevent accidents such as borehole wall collapse, the organic-inorganic nanocomposite gel is particularly suitable for nano-sealing of shale stratums, and the preparation method of the organic-inorganic nanocomposite gel is reliable in principle and has a wide market prospect.

Organic-inorganic nanocomposite gel and oil-based drilling fluid

Disclosed are a high-temperature-resistant tertiary amine-grafted silica nano-plugging agent and water-based drilling fluids, relating to oil-gas field drilling. The nano-plugging agent is prepared from a hydrazine compound, a diallyl compound, an enamine compound, silica particle, and an amino-containing silane coupling agent by stepwise reaction. The nano-plugging agent has a grain size of 58-280 nm.

Growing community of inventors

Chengdu, China

Ruolan Wang