延长天然气探区构造及流体运聚对成藏的控制

目的研究鄂尔多斯盆地南部延长探区天然气气藏特征、(古)构造及(古)流体演化特征,探索该区域天然气成藏的控制因素。方法 (古)构造及(古)流体(演化)恢复及成藏控制因素综合分析法。结果 (古)构造或(古)流体运聚特征控制着盆地南部,三叠纪至晚白垩纪地层抬升剥蚀后,延长天然气探区发育有继承性构造高部位,该构造高部位是有利成藏区之一;在构造低部位,流体运聚的持续指向区是另一类型天然气有利成藏区。结论探区具有两类典型规模气藏,即宽缓背斜构造特征控制下的构造气藏和流体运聚特征控制下的岩性气藏。相对较好的储层条件、宽缓背斜构造以及流体(天然气)的继承性运聚条件3方面因素是该区宽缓背斜构造气藏形成的控制因素,而良好的储层条件、流体运聚特征两方面因素是该区岩性气藏形成的控制因素。

Tectonic and fluid migration and accumulation taking control to Gas Accumulation in Yanchang exploration area,Ordos Basin

Aim To study the elements of gas accumulation.Methods By studying on the evolution rules of tectonics and fluids.Results Paleostructure or paleofluid migration & accumulation are predominant in the controlling factors of gas-accumulation in the southern area of the Basin.The Upper location of the structure took inheritance and development,which are one of the favorable zones for gas-accumulation,whereas the fluid migrated to Lower location of the structure sustainably,also became the different type of the favorable zones for gas-accumulation.Conclusion Two types of gas reservoir typically were found that tectonic gas reservoir under the contol of relief anticline and lithologic one under the control of fluid migration and accumulation.Also,the controlling elements for gas accumulation are good reservoir conditions relatively,relief anticline and fluid migration and accumulation successively and the latter two play controlling role in gas accumulation for lithologic gas reservoir in this area.