Production control method for discharge and mining stage of coal-bed methane well in southwest

Abstract

Disclosed is a production control method for a discharge and mining stage of a coal-bed methane well in the southwest. The production control method comprises the steps that a law of coal-bed water production is gradually found out in an early stage of drainage; water production and pulverized coal production are observed; the decreasing amplitude of a dynamic liquid surface is controlled to be within the 1-6m/d by using a bottom hole pressure gauge; if the dynamic liquid surface drops fast, a discharge and mining system is lowered; if the dynamic liquid surface picks up, the discharge and mining system is raised, it is ensured that the pulverized coal is not produced in large quantities, when the water yield is obviously decreased, by this time, water in a coal bed is discharged in largequantities, a large area of a pressure drop funnel is formed, and the liquid surface is controlled to be above 10-15m of a coal bed top boundary, so that it is ensured that all the coal bed sections are below the coal bed water; two-phase gas-liquid flow which maintains the fact that in the coal bed, coal-bed methane is major and the water is minor is beneficial to carry out the remaining water inthe coal bed during gas producing, and the output pulverized coal is carried to the ground and avoided piling up in a wellbore and a pump barrel; and meanwhile, and bottom hole flow pressure is controlled by controlling wellhead casing pressure, and the purposes that the stable production period is prolonged and the gas yield of a single well is increased are achieved.

Description

technical field [0001] The invention relates to the technical field of coal-bed methane development, in particular to a production control method for coal-bed methane wells in Southwest China during the drainage and production phase. technical background [0002] At present, my country's coalbed methane development main battlefield is in Shanxi. Many theories and development practices of coalbed methane are basically formed in the large-scale development of Shanxi's coalbed methane. The main coal seams in Shanxi, Shanxi Formation and Taiyuan Formation coal are mainly lump coal, while the Southwest region is mainly composed of structural coal, and the main coal seam is mainly crushed coal. Therefore, according to the geological characteristics of the crushed coal seam in Southwest China, By comprehensively utilizing the results of coalbed methane drilling, geology, and fracturing, combined with the analysis and demonstration of production curves, based on the practical theory o...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the defects of the prior art, the object of the present invention is to provide a production control method for coalbed methane well drainage in Southwest China. According to the production law of coalbed methane and the standard curve template, the production process of coalbed methane is divided into liquid production exploration, stable reduction pressure, critical gas production, pressure-controlled liquid drainage, pressure-controlled gas production,