鄂尔多斯盆地吴起地区长6储层裂缝系统研究及意义

摘要

The article bases on regional outcrop fracture observation and integral fracture cognition.By observing frac-tures in core samples,studying imaging logs data and materials under microscope,we studied WuQi chang-6 oil reser-voir's fracture characters about it's scale and causes.The research shows that the area mainly develops two kinds of frac-ture:structural fracture and diagenetic fracture.Among them,the majority of structural fractures are high-angle and nearly vertical and it's crack angle ranges from 61°to 84°,the average is 81°.The fractures is poorly filled.Besides,WuQi chang-6 oil reservoir generally develops two kinds of non-structural fracture—bedding fissure and diagenesis microfracture. Combining practically measured ground stresses and dynamic monitoring data,we conclude that chang-6 oil reservoir's artificial fracture extension direction is about NE–SW.Fracture system composed by artificial fractures and natural frac-ture controls the result of water injection in super-low permeability reservoir.%在区域露头裂缝调查取得宏观裂缝整体认识基础上，通过岩心裂缝观察、成像测井资料识别及镜下资料等，对吴起地区长6油藏不同规模、不同成因裂缝特征进行研究。结果表明，该地区主要发育构造缝、成岩缝。构造缝多为高角度缝、近垂直缝，裂缝倾角为61°~84°，平均81°，裂缝充填程度差。此外，该油藏还普遍发育层理缝及成岩微破裂缝。结合实测地应力及人工裂缝动态监测资料，认为长6储层人工裂缝扩展方向为NE向，并与天然裂缝组成裂缝系统，控制着超低渗储层的注水开发效果。