Method for mining coalbed gas through V-shaped well set

Abstract

The invention provides a method for mining coalbed gas through a V-shaped well set. The method comprises the steps that the V-shaped horizontal well set is a horizontal communication well set formed by connecting two horizontal wells and a vertical well in a butt joint mode at the same position, and is actually formed in the mode that the two U-shaped wells form a certain included angle and share the discharging and mining vertical well; and after the two horizontal wells communicate with the vertical well and are fractured, formation liquid are separately discharged through the two horizontal wells and flows into the same discharging and mining vertical well shaft. Mutual discharging, mining and depressurization gas production is achieved, the number of discharging and mining construction vertical wells is decreased, the effective supply range is widened, and the development cost is reduced; and by means of the height difference between the horizontal wells and a vertical well objective interval, water discharge and gas production are achieved through the vertical well, the transformation volume of a coal bed is increased, the permeability of the coal bed is improved, liquid loading in horizontal well sections is reduced, abrasion to a discharging and mining pipe column is relieved, the development effect of the coalbed gas is effectively improved, the average gas production rate per well reaches 4345 m<3> / d and is over four times that of a vertical well or above, and economic benefit prospects are good.

Description

technical field [0001] The invention relates to coalbed methane exploration and mining technology, in particular to a coalbed methane V-shaped well group mining method. Background technique [0002] The structure of the coal-bearing geological layer is complex. After coal formation, it experienced strong tectonic movement and enhanced plasticity. The traditional coalbed methane mining technology uses a combination of single horizontal well and vertical well for drainage and depressurization gas production, and the original fracture cannot be further expanded during hydraulic fracturing. And cleat, can not produce new longer hydraulic fractures, the effective fracturing stimulation area is small, the gas production rate is low, and the number of vertical wells is too large, time-consuming, labor-intensive, high development cost, affecting the stimulation effect. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a V-...

AI Technical Summary

Problems solved by technology

[0002] The structure of the coal-bearing geological layer is complex. After coal formation, it experienced strong tectonic movement and enhanced plasticity. The traditional coalbed methane mining technology uses a combination of single horizontal well and vertical well for drainage and depressurization gas production, and the original fracture cannot be further expanded during hydraulic fracturing. And cleat, can not produce new longer hydraulic fractures, the effective fracturing stimulation area is small, the gas production rate is low, and the number of vertical wells is too large, time-consuming and labor-intensive, high development cost, affecting the stimulation effect

Images