黔中隆起及周缘地区灯影组古岩溶储层发育特征和控制因素

The development features and controlling factors of reservoirs of Sinian Dengying Formation in central Guizhou uplift and its adjacent areas

黔中隆起及周缘地区的上震旦统灯影组经历了震旦纪末的桐湾运动,发生了古风化壳岩溶作用,形成了一系列的岩溶储集空间。通过样品物性测试、薄片分析、野外观测等手段,从岩性、沉积相、白云岩化、构造等内外控制因素对岩溶储集空间的成因进行了分析。虽然灯影组属于低孔低渗储层,但较强的水动力环境形成的藻(屑)白云岩仍具有较高的孔隙度。白云岩化作用使储层的孔隙度增大,增加了岩石的可溶性;沉积间断使岩石经历了大气淡水的风化淋滤,形成了以裂缝及孔洞为主的储集空间。灯影组古岩溶储层在研究区内具有良好的发育条件,将为中国南方寻找深部油气资源提供极为重要的场所。

Upper Sinian Dengying Formation in central Guizhou uplift and its adjacent areas experienced the Tongwan movement at the end of Sinian Period, which resulted in the karstification of the paleo-weathering crust. A lot of reservoir space was formed in this period. This paper analyzed the genesis of the reservoir space on the basis of investigating such controtling factors as rock characteristics, sedimen- tary facies, dolomite and structure by means of testing samples, analyzing flakes and conducting field work. Although both porosity and permeability of Derlgying Formation are low, the porosity of alga dolomite formed under the strong water dynamic condition remains rel- atively high. In addition, the dolomitization effect increased the porosity of rocks. As a result, the solubility of rocks became higher. The sedimentation hiatus caused the leaching of rocks by atmosphere water, accompanied by the formation of some reservoir space. In conclusion, the formation condition of Dengying Formation paleo-karst reservoirs was very favorable in the study area. The central Guizhou uplift and its adjacent areas will become very important places for the exploration of petroleum resources in southern China.