Coal reservoir water locking damage control method

Abstract

The invention relates to a coal reservoir water locking damage control method, which comprises the following steps that:1, a ground coal-bed gas well subjected to fracturing transformation is selected; 2, reservoir coal samples are collected on sites, and the contact angle of water on the coal sample surface is tested in an indoor position; 3, quickly penetrating agents T and chlorine dioxides are added into fracturing fluid, the concentration of the quickly penetrating agents T is selected according to the contact angle of the water on the coal sample surface, and the concentration of the chlorine dioxide is selected according to the coal rank of the coal samples (the metamorphism degree of the coal samples); 4, after the quickly penetrating agents T and the chlorine dioxides are added, the uniformly stirred fracturing fluid can be used as ahead fluid, or is used as sand-carrying fluid to be subjected to joint hydraulic fracturing with non-active water fracturing fluid, and 20 to 30 cubic meters of active water fracturing fluid needs to be pumped between the ahead fluid and the sand-carrying fluid for isolation; and 5, the fracturing fluid return and discharging can start only after at least 3 hours from the hydraulic fracturing completion. The coal reservoir water locking damage control method has the advantages that the capillary resistance and the surface tension of a coal-bed gas reservoir layer are reduced; the reservoir layer water locking damage is reduced; the coal-bed gas reservoir layer is favorably protected; and the coal-bed gas recovery rate is favorably improved.

Description

technical field [0001] The invention belongs to the technical field of coalbed methane exploration and development coalbed methane well reservoir reconstruction technology, and in particular relates to a method for controlling coal reservoir water lock damage. Background technique [0002] The coal reservoir conditions of low permeability, low impending storage pressure ratio, and low gas saturation in my country are not conducive to the commercial development of coalbed methane. The methane-friendly ability and other aspects of coal reservoirs have been studied, and certain effects have been achieved in the transformation of coal reservoirs. However, most of the research results did not involve or pay attention to the reservoir damage caused by reservoir stimulation. [0003] Water lock effect is one of the main factors causing damage to coalbed methane reservoirs. The coalbed methane reservoir is a complex porous medium. After the foreign fluid invades, the gas in the fra...

AI Technical Summary

Problems solved by technology

However, most of the research results did not involve or pay attention to the problem of reservoir damage caused by reservoir stimulation.