塔里木盆地北缘碳酸盐岩野外构造裂缝发育规律研究

摘要

More and more attentions have been paid to marine carbonate oil and gas exploration. Although carbonate rocks are normally dense, a variety of geological processes can make the carbonate rocks to become good oil and gas reservoirs. By analyzing fracture features of the carbonate rocks in the northern margin of Tarim Basin, we pointed out that lithology, stratum thickness, weathering crust, fluid transformation, and tectonics played an important role in fracture development. Coarse crystal dolomites are prone to developing more fractures than do fine crystal dolomite;More fractures are produced in thinner strata than thicker ones;More fractures are formed at the top of the weathering crust than at its bottom;The presence of fluid is conductive to fracture development while the effectiveness of the fracture development is reduced after the fracture is being filled;The greater curvature of the folds, the more fractures;Also, more fractures will occur near the fault and decrease exponentially with distance away from the fault.%海相碳酸盐岩的油气勘探日益受到我国的重视。碳酸盐岩通常比较致密，需要通过各种地质作用的改造才能成为良好储层。本文通过对塔里木盆地北缘碳酸盐岩野外构造裂缝发育情况的分析，认为岩性、层厚、风化壳、流体改造和构造作用等因素是控制碳酸盐岩构造裂缝发育情况的主要因素。粗晶白云岩裂缝比细晶的发育；岩层越薄，裂缝越发育；风化壳上部有利于裂缝发育；热液作用有利于裂缝扩展，但充填后降低裂缝的有效性；褶皱的曲率越大，裂缝越发育；靠近断层裂缝发育，裂缝密度与距断层的距离呈指数关系。