关键词: 塔里木盆地, 奥陶系, 碳酸盐岩, 断裂带, 裂缝特征, 裂缝期次, 有效缝, 控制因素, 应力场

Abstract: The fracture system of the Ordovician limestone reservoir is irregular and complicated which has the characteristics of welldeveloped high-angle tenso-shear micro-small fractures in the Tazhong No.1 fault belt of Tarim Basin.Non-structure genetic fractures include solution-fracture and diagenetic-fracture. The structure genetic fractures consist of calcite-filled high-angle bigmiddle fractures."X" type shear-fractures and horizontal fracture.On the basis of its cut-and-fill features, the fracture system can be further divided into four-stage genetic fractures with different features.With the new logging interpretation technology, the strike of the effective fractures are nearly perpendicular to Tazhong No.1 fault belt,but the calcite-filled fractures are subparallal to it.The comprehensive analyses and studies indicating that the effective of the fracture is mainly controlled by present regional stress field and long-term compressional stress field of paleostructure, ect.But the fracture density has less relation with the local structure curvature.Fracture pool is an important exploration object for the Ordovician limestone along Tazhong No.1 fault belt.

Key words: Tarim Basin, Ordovician, carbonate rock, fault belt, fracture characteristics, fracture stage, effective fracture, control factor, stress field