Plugging agent for low-pressure leakage gas well, and preparation method and application method thereof

Abstract

The invention discloses a plugging agent for a low-pressure leakage gas well, and a preparation method and an application method thereof. The plugging agent is prepared through the following steps: 1)stirring 0.3-0.7wt% of guanidine gum dry powder and clear water for mixing to form a mixture, and stirring at a constant temperature for 45-60 min; 2) adding 2-5% of calcium carbonate powder of whichthe particle size is 1000-2000 meshes into formed guanidine gum liquid after mixing, and stirring at the constant temperature for 20-30 min; 3) adding 1-3% of a polyvinyl alcohol fiber of which the length is 6-10 mm and the diameter is 20 Am into mixed liquid, and stirring at the constant temperature for 20-30 min; 4) adding 0.3-0.5% of an expanded particle of which the particle size is 1-3 mm into the mixed liquid, and stirring at the constant temperature for 1-3 min; 5) adding 0.3-0.5% of an expanded particle of which the particle size is 0.025-0.425 mm into the mixed liquid, and stirring at the constant temperature for 1-3 min to obtain the plugging agent for the low-pressure leakage gas well. The plugging agent can be directly used for the well repairing and leaking stoppage construction of the leakage gas well, and technical support is provided for a well repairing field well control operation; in addition, the plugging agent is simple in plug removal measure, and plug removal can be carried out through the injection of a plugging remover.

Description

technical field [0001] The invention belongs to the technical field of oilfield chemistry, and in particular relates to a plugging agent for low-pressure leakage gas wells, a preparation method and an application method thereof. Background technique [0002] Gas wells have been in production for a period of time, especially after the development of gas fields has entered the middle and late stages, various abnormal situations will appear in the wells, and due to the continuous attenuation of formation energy, normal production cannot be carried out. Therefore, it is necessary to perform workover operations on these low-pressure gas wells , Such as: replacement of production pipe strings, inspection of layers and repairing holes, salvage of bridge plugs and other workover measures to ensure that the gas well resumes production. [0003] When carrying out workover or potential tapping and reconstruction operations, it is necessary to consider the stability of the well and the ...

AI Technical Summary

Problems solved by technology

However, these old wells are under low pressure due to long-term mining. If conventional downhole operations are used for workover and potential tapping, because the formation pressure is already far lower than the fluid column pressure of the wellbore, the killing fluid is easily lost into the formation, resulting in formation failure. Medium clay swelling and particle migration can block pores, reduce permeability, and cause serious pollution damage to reservoirs, which may cause gas wells to be crushed, resulting in a significant reduction in gas well production or loss of original producing layers. There is a wellhead fire, H 2 Unsafe factors such as S poisoning

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