煤层气水平井降压漏斗扩展规律研究

Pressure drop funnel extension of coalbed methane horizontal well

为了揭示煤层气水平井排采降压漏斗扩展规律,采用理论分析和数值模拟方法,分析了煤层气水平井排水形成区域降压及井间干扰的过程,排采三年后产生井间干扰作用,排采五年后平均采收率达到60%.提出了三段式管理井底压力的排采方法,实现水平井降压、提产、稳产,减少卡泵事故和修井作业.研究结果表明:水平井压降幅度与采收率呈正比;三段式管理井底压力的排采方法有利于区域压降扩展,充分释放煤层气井产能.

To understand the extension properties of pressure drop funnel around coalbed methane horizontal wells,using theoretical analysis and numerical simulation method,the regional pressure drop and inter-well interference process were analyzed in this study.The analysis shows that the inter-well interference effect occurs after three years extraction,and the average recovery rate reaches 60% after five years extraction.Therefore,a production method is proposed,which uses a three-stage management method to control bottom hole pressure(BHP).The proposed method realizes pressure drop,improves and stabilizes the production of horizontal well,and reduces the accident of pump blocking and well repairmen.Study results demonstrates that the horizontal well pressure drop is directly proportional to recovery rate,and the three-stage BHP control production system can reduce regional pressure and improve CBM well productivity.