川东石炭系气藏气井结垢预测及防治

Prediction and prevention on scaling of gas wells in Carboniferous gas reservoirs in east Sichuan

川东石炭系气藏高含H2S和CO2,在气田开发过程中大量产出地层水,且其矿化度高,绝大部分为0.17～155.45g/L。地层水中钙、镁等阳离子与碳酸根离子结合而结垢,影响气井正常生产。在对川东石炭系气藏产出地层水矿化度及水型统计分析的基础上,讨论了川东石炭系气井碳酸钙结垢机理。以川东石炭系某气藏A,B井为例,采用饱和指数法预测模型对其结垢趋势作出预测,结果显示,2口井在生产过程中会形成碳酸钙垢。文中简要介绍了油气作业常用的除、防垢方法,并分析了其优缺点,详细介绍了电子超扫除防垢方法的原理及其适应性。川东现场应用情况表明,采用电子超扫防除垢方法对川东石炭系气藏气井防除垢,效果良好,可为同类气藏气井防除垢提供借鉴。

Most of Carboniferous gas reservoirs in east Sichuan contain high H2S and CO2, and produce a large amount of formation water in the process of exploitation. The salinity of formation water is high with a range of 0.17-155.45 g/L. The scale will form when cations mix with carbonate ions, thus affecting the normal production of gas well. Based on the statistical analysis of salinity and types of formation water produced in gas reservoirs in east Siehuan, the scaling mechanism of CaCO3 in gas producing wells is discussed, and the different sealing prediction techniques are introduced whose advantages and disadvantages are diseussed. Saturation index method is selected to predict the scaling tendency of A and B gas wells in Carboniferous gas reservoir in east Sichuan. Resuhs show that the two wells will form seale during the production process. Different scale removal methods are analyzed and the principle, and the adaptability of electronic ultrasonography method are introduced in detail. Based on the field application, the electronic uhrasonography method is selected for the scale removal in Carboniferous gas reservoirs in east Sichuan, which can provide referenee tbr the method selection in the similar gas reservoirs.