Research on Comprehensive Evaluation Method of Hydraulic Fracturing Gas Drainage Effect in Underground Coal Mine and its Engineering Application

Abstract

Aiming at the engineering problems of current single evaluation of underground coal mine hydraulic fracturing effect, low quantification accuracy, lack of multi-dimensional coupling evaluation, which makes it difficult to accurately characterize the comprehensive effects of fracturing crack creation, pressure relief and permeability enhancement, this paper systematically sorts out the existing fracturing effect monitoring and evaluation technology system, and summarizes the technical characteristics and applicable scenarios of each evaluation method. Combined with different engineering scenarios such as hard roof pressure relief, coal seam permeability enhancement and rock burst prevention and control, a multi-dimensional quantitative evaluation index system covering fracture development characteristics, stress relief effect, surrounding rock deformation control, gas control effect and construction efficiency is constructed. The entropy weight-analytic hierarchy process coupling model is introduced to realize the scientific assignment of evaluation index weights, and a five-level comprehensive evaluation method for hydraulic fracturing effect is established. The engineering application results show that this evaluation system can accurately quantify the effect of underground hydraulic fracturing reconstruction, effectively avoid the one-sidedness of a single evaluation method, and the evaluation results are highly consistent with on-site mine pressure monitoring and fracture detection data. It can provide theoretical support and technical basis for parameter optimization, process improvement and accurate judgment of engineering effect of underground coal mine hydraulic fracturing.