川西坳陷合兴场-丰谷地区须家河组致密砂岩气藏精细勘探

为了提高致密砂岩气藏的勘探成功率,以川西坳陷合兴场-丰谷地区须家河组致密砂岩气藏为例,建立了以地质综合研究为指导,地震、地质紧密结合的精细勘探技术。合兴场-丰谷地区须家河组致密砂岩气藏精细勘探的核心,是在砂组精细等时划分及对比的基础上,以砂组为单位,将生产动态资料与静态地质特征相结合进行典型气藏解剖,明确气藏特征及成藏主控因素;通过加强地震预测、钻井跟踪、测试选层及工程工艺过程中的地质综合研究,完成油气富集区预测及井位部署,且在钻井跟踪过程中即时修正认识,提高钻探成功率。精细勘探的结果显示,研究区气藏具水溶脱气特征,为古构造-成岩圈闭气藏,控制成藏的关键因素是古构造高部位,其中须二段的CH148-CH137-GM3井区和GM2-CG561井区及须四段的GM2-CG561-GM4井区和CF563-CF175井区被预测为有利油气富集区。

Fine exploration of tight sandstone gas reservoirs in the Xujiahe Formation, Hexingchang-Fenggu area,the western Sichuan Basin

A set of fine exploration technologies had been developed and applied to improve exploration success rate in the tight sandstone gas reservoirs in the Upper Triassic Xujiahe Formation in Hexingchang-Fenggu area,western Sichuan Basin.Guided by geological understandings and based on seismic data,the technologies are employed to study the tight sand gas reservoirs through fine division and correlation of sand groups as well as integration of dynamic performance with static geological features.The gas reservoir characteristics were described and the main controlling factors were identified.Sweet spot prediction and well emplacement were carried out through strengthening seismic prediction,drilling tracing,testing layer selection as well as comprehensive geologi-cal study during stimulation.The success rate of exploratory drilling has been greatly improved through real-time modification of drilling program during drilling operation.Fine exploration of the Hexingchang-Fenggu area reveals that the gas reservoir has the characteristics of water-soluble gas.It can be classified as paleo-structural-lithological trap,with paleo-structural high controlling gas accumulations.Four play fairways were identified:the wellblocks of CH148-CH137-GM3 and GM2-CG561 with the second member of Xujiahe Fm as the target,and the wellblocks of GM2-CG561-GM4 and CF563-CF175 with the fourth member of the Formation as the target.