页岩气井三角图版法判别井筒积液研究

针对四川盆地页岩气田CN201井区大部分气井进入生产中后期,产能降低,携液能量不足,井底积液严重,气井采收率降低的问题,根据该区块生产特征,综合考虑积液敏感的井口压力、日产气量、水气比3个生产参数,对实际数据进行归一化或极值化处理以消除参数单位及数量级影响,绘制三角图版,分析散点分布规律,确定井筒积液区域。结果表明:井口压力占比为42.38%～76.39%、日产气量占比为0.0～51.5%、水气比占比为0.0～52.7%为CN201井区页岩气井积液判别区。流压测试结果显示三角图版准确程度为84.3%,证明该方法判别页岩气井积液可靠性高。该研究对确定气田现场排液时机、排液工艺类型及排液效果评价等提供了理论基础。

Shale Gas Wellbore Liquid Loading Identification Based on Triangle Plate

In order to improve the productivity decline, insufficient liquid-carrying capacity, serious wellbore liquid loading, low recovery and other problems in the middle-late stage for the most gas wells in the Wellblock CN201 of shale gas field in Sichuan Basin, the actual production data were normalized and extremalized to eliminate the influence of parameter unit and magnitude order by comprehensively considering wellbore pressure, daily gas production and water-gas ratio according to the production performances. A triangle plate was given to analyze the scattered point distribution and determine the wellbore liquid loading area. Result indicates that the shale gas wellbore liquid loading zones for the Wellblock CN201 includes the wellhead pressure proportion is 42.38%～76.39%, the daily gas production proportion is 0.0～51.5% and the water-gas ratio proportion is 0.0～52.7%. Flowing pressure test indicates a accuracy of 84.3% for this triangle plate, which is highly reliable to identify shale gas wellbore liquid loading. This research could provide certain theoretical reference for determining on-site liquid discharge timing, liquid discharge process and liquid discharge performance evaluation.