Hydrogen-bonded hydrogel suitable for plugging of cracks and cavities

Abstract

The invention discloses hydrogen-bonding hydrogel suitable for plugging cracks and caves. The hydrogen-bonding hydrogel comprises raw materials in parts by weight as follows: 5-10 parts of polyvinyl alcohol, 10-30 parts of polyols, 1-5 parts of a catalyst, 15-25 parts of salt, 0-100 parts of a weighting agent and 100 parts of water. The gelling time of the hydrogel is controllable, the initial setting time of the hydrogel is 120-240 min according to requirements of different layers, the time interval can basically meet most construction requirements, and the hydrogel can be formed from the room temperature to 90 DEG C; the hydrogel has sufficient strength, has certain cementing power with a formation, and cannot be crushed or remain in the cracks when bearing the pressure difference between a fluid in a well and the formation.

Description

technical field [0001] The invention relates to a plugging gel used in the field of petroleum drilling engineering, in particular to a hydrogen-bonded hydrogel suitable for leak plugging of cracks and caves. Background technique [0002] The exploration and development of shale gas has gradually emerged in China, forming a certain scale of exploration and development, and entering a stage of rapid development. The well leakage phenomenon in the Fuling shale gas block is becoming more and more serious. There are a large number of fractures developed. The size of the fractures ranges from 1mm to 8mm. Mud is often lost. It is urgent to design a suitable plugging scheme and plugging method according to the actual situation. leaky system. [0003] The gels used for plugging in China are mainly cross-linked and non-cross-linked, there are weak gel composite plugging materials for plugging, and pure fluid plugging gels, each of which has its own characteristics and advantages. sc...

AI Technical Summary

Problems solved by technology

[0008] 1) The gel time is too long. According to the requirements of the construction time, the gel time is too long not only affects the construction progress, but also easily leads to complex situations at the bottom of the well

[0009] 2) The form of gel-bonded particle bridge plugging cannot seal large cracks, and the plugging slurry tends to flow away along the cracks

[0010] 3) The pure gel process from liquid to solid has not been realized, and it is difficult to completely seal irregular cracks

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