Operating device and method for cleaning near-well polluted area of ​​coalbed methane well

Abstract

The invention relates to an operation device for cleaning the polluted area near the well of a coalbed methane well, which includes a liquid distribution tank, a pump truck, a foam generator, a nitrogen making train unit, a blowout preventer, a fluid channel switching device, a cock valve, a well cleaning return Pipeline, flowback liquid storage tank, well cleaning operation string; the pump truck is connected to the liquid distribution tank and foam generator through the pipeline; the first port of the foam generator is connected to the pump truck through the pipeline, and the second port is connected to the nitrogen generator through the pipeline The train group is connected, and the third port is connected with the injection gate valve through the pipeline; the first port of the wellhead device is located at the bottom of the wellhead device, and the second port is located at the top of the wellhead device and connected with the blowout preventer to control the discharge of bottom hole fluid; the first port at the bottom of the wellhead device It is connected with the annulus between the wellbore of the coalbed methane well and the well washing operation string. During the well flushing operation, the nitrogen foam well flushing fluid is injected through the annulus between the coalbed methane well bore and the well washing operation string. The operating device has high cleaning efficiency, less formation filtration loss of well-washing fluid, less water consumption, and strong ash-carrying ability of well-washing fluid.

Description

technical field [0001] The invention belongs to the field of oil and gas resource development, and in particular relates to an operating device and method for cleaning the polluted zone near the well of a coalbed gas well. Background technique [0002] CBM wells will cause different degrees of pollution to the strata near the well after fracturing operations. At the same time, during the drainage production process of CBM wells, the fly ash in the coal seam will be carried to the near well to block water and CBM transport to the wellbore. Therefore, it is urgent to clean the pollutants in the vicinity of the coalbed methane well to improve the productivity of the coalbed methane well. At present, the methods for cleaning near the wellbore of coalbed methane wells mainly include: CO 2 Cleaning method, nitrogen cleaning method, hydraulic shock wave cleaning method and hydraulic shock cleaning method. These methods mainly have the following technical shortcomings in the proce...

AI Technical Summary

Problems solved by technology

[0007] For the current CO 2 , nitrogen, hydraulic shock wave and hydraulic shock cleaning methods exist in the cleaning of pollutants in the near-wellbore zone of coalbed methane wells, serious formation leakage, large water consumption, poor economy, low efficiency (poor ash-carrying ability), long construction period, and serious reservoir pollution. And the shortcoming of incomplete ash removal, the present invention provides a kind of operating device and method that utilizes nitrogen foam well flushing fluid to clean the polluted area near the well of coalbed methane well, overcomes the problem of using CO 2 , Nitrogen, hydraulic shock wave and hydraulic shock cleaning methods have the above shortcomings, which improves the cleaning efficiency and avoids the secondary pollution caused by the cleaning operation to the reservoir

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