Weak cross-linked high polymer for oil-based drilling fluid leakage stoppage and preparation method thereof

Abstract

The invention provides a preparation method of a weak cross-linked high polymer for oil-based drilling fluid leakage stoppage. The preparation method comprises the following steps: mixing a high polymer containing active groups, an oil-soluble cross-linking agent, an oil-soluble initiator and a solvent, heating to react, and granulating to obtain the weak cross-linked high polymer for oil-based drilling fluid leakage stoppage, wherein the high polymer containing active groups is one or more of polybutadiene, polyisoprene, polybutadiene-styrene, polyacrylonitrile-butadiene-styrene and the like. According to the invention, a modified material of a high polymer containing active groups is adopted, and the elastic deformation of the material is improved through crosslinking modification on the basis of the oleophylic cohesiveness of the high polymer. At the leakage layer temperature, the non-crosslinked part of the high polymer gradually absorbs oil and becomes sticky, so that the residence property of the leaking stoppage material in an oil phase can be improved; and a cross-linked part is still in a rubber state, has elastic deformation, and is beneficial to blocking pores with different particle sizes. Under the pressure of a leakage layer, the high polymer particles are adhered together, so that the damage resistance of a plugging layer is improved.

Description

technical field [0001] The invention relates to the technical field of oilfield chemistry, in particular to a weakly cross-linked high polymer for oil-based drilling fluid plugging and a preparation method thereof. Background technique [0002] With the increasing demand for energy in my country and the deepening exploration and development of unconventional oil and gas resources, more and more complex formations are encountered at this time, and the demand for oil-based drilling fluid plugging technology is gradually increasing. The development and application of materials suitable for oil-based drilling fluid plugging are relatively slow. At present, conventional plugging materials such as rigid granular materials of different particle sizes, fiber materials, and deformable materials are still used for plugging in China. However, most of these conventional plugging materials are hydrophilic and have poor compatibility in oil-based drilling fluids, resulting in poor retent...

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Problems solved by technology

However, the crosslinking reaction disclosed in the prior art is difficult, the reaction process and structure are not easy to control, and at the same time, it is difficult to reside in the oil phase environment, the plugging layer is relatively loose, and it is difficult to gradate with the pore particle size.

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