鄂尔多斯盆地东缘临兴地区上石盒子组成藏特征

临兴地区位于鄂尔多斯盆地东缘晋西挠褶带，上石盒子组气藏普遍发育。通过储集岩特征分析、流体包裹体测试分析、盆地模拟技术，结合区域构造演化、测井和试气等相关资料，分析了临兴地区上石盒子组成藏地质条件和基本特征，探讨了上石盒子组成藏主控因素。研究表明：煤系烃源岩在早侏罗世开始生烃增压，持续时间长，剩余压力大，为天然气充注提供了动力条件；上石盒子组地质历史时期最大埋深相对较浅，储层处于中成岩A阶段，致密化程度较低，储层物性具有特低渗气藏特征，有利于天然气的运移和聚集；此外，临兴地区中、下二叠统内未形成异常高压阻隔带，为油气向上运移提供了便利条件。研究认为上石盒子组气藏是天然气自下而上长期连续充注的结果，气藏形成时间可能早于早白垩世紫金山隆起。勘探开发效果表明，上石盒子组天然气富集受储层物性及成藏时期古构造双重因素影响。

Accumulation characteristics research of Shangshihezi Formation in Linxing block,eastern margin of the Ordos Basin,China

Linxing area is located in Jinxi flexural structural belt, eastern margin of the Ordos Basin, China. The gas reservoir of Shangshihezi Formation is widely developed in this area. Based on reservoir rock characteristics analysis, basin simulation technology and fluid inclusions test, combined with regional structural evolution, well logging, gas production test and other relevant data, the geological conditions and reservoir formation characteristics were studied and the main controlling factors of gas enrichment of Shangshihezi Formation in Linxing area were discussed. Results show that the coal seam began to generate hydrocarbon and pressurized in the Early Jurassic with long duration and high residual pressure, which provides the dynamic conditions for gas charging; the maximum burial depth of the Shangshihezi Formation is relatively shallow, and the reservoir is in the middle diagenesis stage A with low densification degree. The reservoir physical property is characterized by ultra-low permeability gas reservoir, which is conducive to the migration and accumulation of natural gas. In addition, lack of abnormal high pressure barrier provides a convenient condition for the gas upward migration. It is considered that the gas reservoir of Shangshihezi Formation formed earlier than the eruption of Zijinshan volcanic, and the gas reservoir is a result of long-term continuous charging, densification and accumulation occurred simultaneously. Results of exploration and development show that gas enrichment is significantly affected by the distribution of favorable sand and the paleotectonics during accumulation period.