Stable-pressure extraction and washing system for coal-bed gas well without halting production and method

Abstract

The invention relates to the technical field of development of coal-bed gas, in particular to a stable-pressure pumping system for a coal-bed gas well without halting production. The stable-pressure pumping system for the coal-bed gas well without halting production comprises a plunger pump, an oil pipe and an extraction pump, wherein the oil pipe and the extraction pump are put in a shaft, and the oil pipe communicates with an oil jacket annulus through a bottom suction port; the portion, above the shaft, of the oil pipe is provided with a three-way structure, extraction and washing liquid isinjected into the oil jacket annulus through a safety valve after being pressurized by the plunger pump, under a certain working system of the extraction pump, extraction and washing liquid enters the oil pipe through the suction port, and then coal powder and mud in the extraction pump and the oil pipe are washed, and discharged to the ground through a second connector of the three-way structure. The plunger pump has the effect of pressurizing so that the extraction and washing liquid on the ground can be constantly injected into the oil jacket annulus, and by increasing the flow and flow speed of the extraction and washing liquid, the purpose of washing solid-phase substances in the extraction pump and oil pipe, and avoiding pump from getting stuck is avoided. The stable-pressure pumping system does not need special cooperation with tubular columns in the shaft, and thus the safety risk is lowered.

Description

technical field [0001] The invention relates to the technical field of coalbed methane development, in particular to a pumping and washing system and method for non-stop production and pressure stabilization during the drainage and production of coalbed methane wells. Background technique [0002] During the development of CBM, a large amount of coal powder will be produced in the coal seam under the action of drill tool grinding, fracturing fluid flushing and fracturing proppant grinding. It is carried to the wellbore, and finally enters the pump barrel and oil pipe. When the pulverized coal reaches a certain amount, it will cause the pump to be stuck and stop production. [0003] ZL201210026646.8 discloses a method for non-stop pumping and cleaning of drainage wells during coalbed methane exploitation. In the method, a continuous pumping and cleaning pipe string is run into a downhole casing in a coalbed gas liquid drainage well, and a drainage pipe string is run into an ...

AI Technical Summary

Problems solved by technology

The well cleaning string used in this scheme is relatively complicated, and the complex structure of the well cleaning string is likely to cause frequent safety accidents downhole, and the input cost and maintenance cost are relatively high

And if there is a pump stuck phenomenon in the coalbed methane well, the coalbed methane extraction equipment is already in a shutdown state, and this method cannot solve the pump stuck problem in the shutdown state

Conventionally, to solve the problem of pump stuck in coalbed methane wells, the pump is usually checked by lifting the pipe string. It is necessary to mobilize a professional workover team to carry out on-site workover operations. Not only will the cracks in the coalbed methane reservoir be closed to varying degrees, which will affect the permeability of the coalbed methane well and the production capacity of the coalbed methane well, but also it will take a long time for the production capacity of the coalbed methane well to recover due to discontinuous drainage caused by pressure relief.

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