A method for switching between the whole barrel pump and the gas lift pumping method without unloading the casing pressure

Abstract

The present invention relates to coalbed methane development, drainage and utilization technology, specifically a method for coalbed methane wells during the drainage and production process. Due to coal reservoir sand and coal pulverization, the pump efficiency of the whole cylinder pump is reduced, and the drainage and production requirements cannot be met. At this time, It is necessary to change a drainage method, but in the replacement process, it is often necessary to remove the wellhead casing pressure, put out the original pipe string, and replace it with a new drainage method. The present invention compares the similarities and similarities and differences between the whole barrel pump and the concentric tubular gas lift drainage method, and proposes to lower the hollow sucker rod with a strong magnet at the tail to the bottom of the pump barrel without unloading the casing pressure. By using an explosion-proof gas circulation pump on the ground, the gas-water mixture is lifted to the ground to realize the switch between the two drainage methods. The significance of the present invention lies in: 1. The casing pressure is not unloaded when the drainage mode is switched, which protects the fracture system of the coal reservoir and ensures that the production capacity of the coalbed gas well is not damaged; , Pulverized coal, the problem of low pump efficiency.

Description

technical field [0001] The invention belongs to the technical field of coalbed methane drainage, and in particular relates to a method for switching between a full cylinder pump and a gas lift extraction mode without unloading casing pressure. Background technique [0002] During the drainage process of coalbed methane wells, due to the compressibility of the gas, it is difficult to control the gas pressure. Often shortly after the drainage, the coal reservoir will emit sand and pulverized coal, resulting in a serious decrease in the pump efficiency of the whole cylinder pump, which cannot meet the Extraction needs. However, according to the theory of coalbed methane development, the drainage process should be continuous and stable, so as to reduce the damage to coal reservoirs, effectively communicate coal seam cracks, and maximize the productivity of coalbed methane wells. At this time, changing the drainage method requires removing the casing pressure at the wellhead. If...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a drainage process that can switch the drainage mode of the whole cylinder pump to the gas lift drainage mode when sand and pulverized coal are discharged without removing the casing pressure, so as to solve the problem that the whole cylinder pump cannot Meeting production needs

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