Self-cementing plugging agent and plugging method

Abstract

The invention provides a self-cementing plugging agent. The self-cementing plugging agent comprises the following raw materials which are taken as components in parts by weight: 50 to 82 parts of polyvinyl chloride resin, 23 to 37 parts of polyurethane, 78 to 92 parts of ethyl acrylate, 1.3 to 2.4 parts of nitrite, 100 to 120 parts of acrylate emulsion, 2.3 to 5.4 parts of fibers, 2.7 to 3.9 partsof shale inhibitors and the like, wherein the fibers are one of polypropylene fibers, polyacrylonitrile fibers, and polyurethane fibers. The self-cementing plugging agent is simple in formula, low inviscosity, and beneficial to on-site preparation and construction; the self-cementing plugging agent can enter leakage pores or deep parts of cracks, a polymerization reaction is generated among molecules, the viscosity of the system increases rapidly to form a very strong adhesion force on the leakage wall so as to block a leakage layer, once plugging is successful, the effective plugging effectis achieved and well leakage does not occur again; the self-cementing plugging agent has variability, and is not limited by space or the cracks, the system has an anti-dilution property after gelled,and cannot be easily washed away by formation water.

Description

technical field [0001] The invention relates to the technical field of a self-cementing plugging agent and a plugging method, in particular to a self-cementing plugging agent and a plugging method. Background technique [0002] Lost circulation is a common downhole complex situation in oil and gas drilling operations. Due to the different types of lost circulation and many restrictive factors, and because the plugging technology is relatively targeted, it is difficult to have a general model so far. For leak prevention and plugging. [0003] Currently commonly used bridging plugging materials are poorly deformable or have no deformability. If the plugging material is slightly larger than the size of the pores and cracks in the leakage layer or does not match the shape of the pores and cracks in the leakage layer, it will not easily enter the leakage layer. Accumulations are formed on the surface of the leakage layer, which may easily lead to poor plugging effect or repeated...

AI Technical Summary

Problems solved by technology

[0002] Lost circulation is a common downhole complex situation in oil and gas drilling operations. Due to the different types of lost circulation and many restrictive factors, and because the plugging technology is relatively targeted, it is difficult to have a general model so far. for leak prevention and plugging

[0003] Currently commonly used bridging plugging materials are poorly deformable or have no deformability. If the plugging material is slightly larger than the size of the pores and cracks in the leakage layer or does not match the shape of the pores and cracks in the leakage layer, it will not easily enter the leakage layer. Accumulation is formed on the surface of the leakage layer, which may easily cause poor plugging effect or repeated leakage after plugging.

[0004] The current pre-crosslinked gel plugging materials have deficiencies in the plugging process: the internal structure of the system is loose and lacks uniform structural integrity, which leads to insufficient compressive strength of the material itself, and no cementation with the lost zone. It is easy to lose along the leakage channel, resulting in a low success rate; once the conventional gel is formed, the viscosity of the system does not change, and its overall compressive strength is basically constant and does not change with time. In the middle and late stages of the formation, the strength increases extremely Limited, with repeated flushing of drilling fluid in the later drilling process, the probability of re-leakage increases