基于多因素的煤储层气水两相非稳态流入动态评价方法及应用

Evaluation method and application of gas-water two-phase unsteady inflow performance of coal reservoir based on multiple factors

煤层气开发中,流入动态是制定合理排采制度的重要依据,能够最大化延长稳产时间,提高最终产量。针对目前无井底压力与多因素的显式方程来评价非稳态流入动态的问题,采用理论推导和多因素拟合方法,建立了井底压力与时间、应力敏感系数、表皮系数、总产量、启动压力梯度的显式计算模型,同时结合生产数据对模型进行验证,并对井底压力的影响因素进行分析。结果表明,从初始生产阶段到压力稳定阶段,所建模型的准确率可达82.3%~94.76%,可有效评价多种因素对产量和井底压力的影响程度,为优化排采制度提供了技术支持。

In the development of coalbed methane(CBM),the inflow performance is an important basis for for⁃mulating a reasonable production system,which can maximize the stable production time and improve the final production.Aiming at the problem that there is no explicit equation of bottom hole pressure and multiple factors to evaluate the unsteady inflow performance,an explicit calculation model of bottom hole pressure and time,stress sensitivity coefficient,skin coefficient,total production,and start-up pressure gradient is established by using theoretical derivation and multiple factor fitting methods.The model is verified with production data,and the factors affecting the bottom hole pressure are analyzed.The results show that the accuracy of the model can reach 82.3%-94.76%from the initial production stage to the stable pressure stage,which can effectively evalu⁃ate the influence of various factors on production and bottom hole pressure,and provide technical support for op⁃timizing the drainage system.