Quantitative analysis on the effect of engineering paramters on production rate of CBM vertical well in Block L

At present, qualitative analysis on geologic factors is the dominant way to study the influential factors of coalbed methane (CBM) production rate. In this paper, it was proposed to analyze the effect of engineering parameters on production rate from the viewpoint of engineering. Firstly, the parameters related to production rate are screened out by means of grey correlative analysis based on three engineering sectors (i.e. well drilling and completion, fracturing and production). Secondly, the collinear parameters are deleted by means of correlation analysis. And finally, the mathematical model is established for the relation between production rate and engineering parameters, so as to evaluate the effect of engineering parameters on CBM well production rate. The real production rate of 49 wells in Block L was investigated. According to the effect on production rate, the engineering parameters rank in a descending order of liquid reduction rate, fracturing fluid volume, perforation thickness, cumulative water production, shut-in time, soak time, fracturing displacement, gas breakthrough time, total depth, and gas breakthrough casing pressure. The development results were analyzed, and it is shown that the unsatisfying production rate in Block L is mainly caused by high production rate and limestone aquifers connected by induced fractures, which is in accordance with the real situations. As concluded, it is feasible to analyze the effect of engineering parameters on production rate from the viewpoint of engineering, and it provides a new approach for analyzing the main control factors of CBM production rate.