Heat injection and yield increase method for coal bed gas based on hydrofracture multi-branch horizontal well

Abstract

The invention discloses a heat injection and yield increase method for coal bed gas based on a hydrofracture multi-branch horizontal well, which adopts a pulse injection mode to inject a mixed solution into a coal bed, so that a surfactant and nano metal particles in the mixed solution can be in full contact with the interior of a crack, more nano metal particles are adsorbed on the inner surface of the crack, and the surfactant fully reacts with the surface of the coal body to change the surface performance of the coal body; the heat conduction capability of the coal bed is greatly improved; then high-temperature and high-pressure steam is injected into the branch wells, after entering the branch wells, the high-temperature and high-pressure steam continuously impacts, applies pressure and heats the cracks, and the coal seam cracks are further expanded and developed under the action of high temperature and high pressure; after the surfactant is used for pretreating the coal bed, liquid drops condensed in advance cannot greatly influence the heat exchange efficiency of follow-up steam, it is guaranteed that the follow-up steam can make direct contact with nano metal particles, finally, the heat transfer efficiency between the steam and the coal bed is continuously increased, and therefore the coal bed gas yield is greatly increased.

Description

Technical field [0001] The present invention relates to a method of stimulation of coalbed methane, in particular a thermal injection method of hydraulic fracturing stimulation of CBM multilateral wells on. Background technique [0002] CBM is an unconventional gas is a clean energy, which is composed mainly of methane, coal bed methane adsorbed mainly (90%) present in the coal seam. However, CBM generally have buried deep, low permeability, high density, high pressure, adsorption, and other characteristics, resulting in low efficiency of coal-bed methane extraction. In order to more effectively exploit coalbed methane reservoirs need to be modified to improve the coal seam permeability. The most commonly used methods reservoir stimulation hydraulic fracturing, gas drive technologies, blasting technology, however, due to the strong adsorption capacity of coal-bed methane, coal bed methane extraction late, there are still a large number of coal-bed methane adsorbed in the coal not...

AI Technical Summary

Problems solved by technology

However, due to the poor thermal conductivity of coal itself, for some dense coal seams with few cracks, if steam is directly injected, it is difficult for the steam to enter the deep part of the coal body, and ultimately it is impossible to effectively exchange heat inside the coal body.

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