煤层气井压裂效果评价及压裂施工工程因素分析

Evaluation of Coal- bed Methane Wells Fracturing Effect and Analysis of Fracturing Project Influencing Factors

我国煤层气已经进入商业化开采阶段,由于煤层埋深浅,储层压力小且致密,需要进行压裂增产。压裂效果的好坏直接影响到煤层气单井的增产效果,因而必须进行压裂效果评价,建立评价指标,指导压裂设计。目前压裂效果评价通常采用产量评价方法、经济评价方法和裂缝参数计算对比法。其中应用较多的是利用各种数学模型及测试资料对裂缝几何参数进行计算。通过生产数据证实煤层气井压裂后增产效果显著,利用压裂施工曲线获取数学模型中所需参数,对裂缝几何参数(裂缝长度、裂缝宽度)进行计算,建立简单可行的裂缝参数计算模型,计算结果表明:建立的改进模型提高了裂缝几何参数计算的准确率。通过分析裂缝长度和裂缝宽度的影响因素发现,在一定程度内,施工参数与裂缝长度和裂缝宽度线性相关性较好。

China＇s coal bed methane has entered the commercial exploitation phase. Due to the coal seam is shallow, small and dense reservoir pressure, fracture stimulation is needed. Fracturing treatments have a direct impact on the effect of coal-bed methane muhiple yield of single-well stimulation. Therefore, we must carry out fracturing effect evaluation and establish evaluation index to guide fracturing design. At present, the evaluation of fracturing effect usually adopts yield evaluation, economic evaluation methods and fracture parameters calculated contrast method. Among them, the most fre- quently used one is to use various mathematical models to test data on fracture geometry parameters calculation. This paper confirms coalbed methane wells after fracturing yield significant results, and then uses the curve to obtain parameters fractu- ring mathematical models needed to fracture geometry parameters （seam length, slit width） to calculate with production data, and establishes simple and feasible fracture parameters calculation model to calculate. The actual count results show that the improved model improves the accuracy of the crack geometry calculations. By analyzing the factors fracture length and width of the discovery, in a certain extent, the construction parameters and fracture length, width linear correlation better.