关键词: 碳酸盐岩, 　岩溶缝洞, 　奥陶系, 　鹰山组, 　塔里木盆地

Abstract: Paleokarstification is one of the key factors for the formation of marine carbonate reservoirs in Tazhong and north Tarim basin. The interlayer karstification in the middle Tarim basin is quite different from that in the weathering crust in the north Tarim basin. In order to further identify the development pattern of interlayer karst in Tarim basin and analyze the development characteristics of paleokarst. On the basis of previous studies, the stratigraphic loss between the ordovician and overlying strata is clarified. The field profile and typical characteristics of the traditional weathering crust karst and interlayer karst are investigated through field investigation and laboratory core experiment analysis. The results show that the interlayer karst has obvious vertical zoning, and the continuity of karst caves is poor from top to bottom, which are nodular loam zone (residual zone), weathered fracture zone (seepage zone) and dissolution cave zone (subsurface zone). It is also a multi⁃stage cycle, forming interlayer karst development zone of tens of meters, which is a favorable area for oil and gas enrichment. It is considered that the interlayer karstic reservoir in Tarim basin is the result of the superimposed transformation of multi stage karstification.

Key words: Carbonate rock, Karst crack?cavity, Ordovician, Yingshan formation, Tarim basin