鄂尔多斯盆地东南部延长组长7页岩气储层裂缝特征及其控制因素

Characteristics and Controlling Factors of Fractures in Chang 7 Shale Gas Reservoir of Southeastern Ordos Basin

鄂尔多斯盆地三叠系延长组发育多套富含有机质泥页岩,勘探实践表明页岩气勘探前景良好。裂缝研究是页岩气勘探开发研究的重要内容,其对页岩气勘探选区、压力造缝等具有指导作用。笔者通过野外地质调查、岩心观察、铸体薄片等手段,对鄂尔多斯盆地东南部三叠系延长组长7段裂缝特征进行了研究,分析了裂缝控制因素。分析了研究区三种不同尺度的裂缝:露头节理(裂缝)、岩心裂缝、微裂缝。研究结果表明,有机质丰度、矿物成分、岩性是裂缝发育的控制因素。

Several sets of organic - rich shale developed in Yanchang Formation in Ordos Basin. Exploration activities show that there is superior potential for shale gas exploration. The research of shale fractures is one of the key technologies for shale gas exploration and development,which has great significance for shale gas exploration targets and fracture initiation. Based on field geological surveying, core description and casting thin sections, characteristics and controlling factors of fractures in the Chang -7 in the southeast Ordos Basin are analyzed. Fissure in out-crops, core fissure and microcrack are identified. The fracture development depends on organic matter abundance, mineral composition and lithology.