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研究鄂尔多斯盆地南部泾河油田长8油藏天然裂缝的发育主控因素及模式。通过野外露头、岩心、常规测井和成像测井资料,开展井剖面天然裂缝的识别。在数据的处理上,利用单一变量法分别对比工区内断层和裂缝的力学性质、统计裂缝发育指数与相邻断层距离的关系、不同岩性中裂缝的发育情况、裂缝发育指数与砂地比的关系、长8地层的构造曲率与裂缝发育指数的关系,结果表明:断层伴生2组共轭剪切裂缝,只有一组较发育,这些裂缝离断层越近,裂缝发育指数越高;随着泥质含量的增加,岩性逐渐向泥岩转化,天然裂缝的发育程度逐渐降低,平面上看,天然裂缝多发育在砂地比值较高的地方;构造曲率越大,天然裂缝发育的程度越高。泾河地区长8段裂缝发育的主控因素为岩性、构造变形和断层。其中断层对裂缝发育的影响表现在裂缝发育指数随断层距离的增加而减小,并且为控制裂缝发育的最主要因素;岩性中的脆性成分越高,裂缝越发育;构造变形程度越高,构造张裂缝也越发育。
To study the main controlling factors and patterns of natural fractures in Chang 8 reservoir in Jinghe Oilfield, southern Ordos Basin. Identify natural fractures in well sections through field outcrops, cores, conventional logs, and imaging logs. In terms of data processing, the single variable method is used to compare the mechanical properties of faults and fractures in the work area respectively. The relationship between fracture development index and adjacent fault distance, the development of fractures in different lithologies, the relationship between fracture development index and sand ratio The results show that there are only two sets of conjugate shear fractures associated with faults, and the closer these fractures are to the fault, the higher the fracture development index is. As the content increases, the lithology gradually transforms into mudstone, and the development degree of natural fractures gradually decreases. In the aspect of plane, the natural fractures mostly develop in places where the ratio of sand and sand is high; the higher the structural curvature is, the higher the degree of natural fractures is. The main controlling factors of fracture development in Chang 8 of Jinghe area are lithology, tectonic deformation and faults. The influence of faults on the development of fractures is manifested in that the fracture development index decreases with the increase of fault distance and is the most important factor for controlling the development of fractures. The higher the brittle components in lithology, the more fractures develop. The higher the degree of structural deformation, Structural cracks more developed.