大牛地气田DP43水平井组的井工厂钻井实践

Drilling practice of a well plant in the cluster horizontal wells of DP43 in the Daniudi Gas Field,Ordos Basin

丛式水平井组技术能节约大量土地并提高单井产量,已在我国的复杂断块油藏开发中得到应用,但还未见在低渗透气藏开发方面应用的报道。为此,借鉴国内外油田、页岩气藏丛式水平井组开发的成功经验,在相关技术调研和气藏地质研究的基础上,在鄂尔多斯盆地大牛地气田进行了一个井场钻6口水平井的工厂化作业实践:①地面井位布置选用排状正对井网,水平段延伸方向与最小主应力夹角小于30°,相邻同方向井的水平段之间距离为500m,以满足储层压裂改造裂缝延伸范围的要求;②钻机采用气动滑轨推动整体搬迁,优化井间距离;③由3台钻机一起钻进,每台钻机实施2口井,共同完成6口水平井钻井工作。现场试验结果表明:该丛式井组平均机械钻速达8.28m/h,同比提高12.8%;平均钻井周期为47.7d,同比缩短8.79%;首次实现了集中打井、集中压裂、集中投产的集约化井工厂建设。结论认为:该开发模式可有效实现降本增效,符合超低渗透气藏开发理念,对同类气藏开发具有重要的借鉴意义。

Cluster horizontal well technology can greatly save the land area and improve the single well yield, so it has already been applied in the development of complex fault block oil and gas reservoirs in China. Its application in low permeability gas reservoirs has not yet been reported. Based on the domestic and foreign successful experiences in the development of oil fields and shale gas res ervoirs in cluster horizontal wells as well as relevant technological investigation and research on gas reservoir geology, a factory-like practice of 6 horizontal wells in one well pad was performed in the Daniudi Gas Field, Ordos Basin. First, the well locations were ar- ranged in a horizontal-row well pattern; the angle between the minor principal stress and the extending direction of the horizontal sec tion was less than 30~; the distance between the horizontal intervals of two adjacent wells in the same direction was 500 m, meeting the requirements of the crack propagation range of reservoir fracturing improvement. Second, the drilling rig was relocated as an in- tegral on pneumatic side rails to optimize the distance between wells. Third, three drilling rigs were used together for drilling, with each drilling 2 wells, thus 6 horizontal wells in total at the same time. The field test results indicated that the average rate of pene tration of the cluster wells was 8.28 m/h, increased by 12.8~; the average drilling cycle was 47.7 days, shortened by 8. 79~. Therefore, the intensified well plant construction with centralized drilling, fracturing and production was realized for the first time. This development mode can effectively reduce cost and improve efficiency, which is consistent with the development concept of ultra low-permeability gas reservoirs, providing important reference for analogous gas reservoir development.