STUDY ON THE FORMATION AND PERMEABILITY OF THE PALAEOKARST IN ORDOVICIAN RESIDUAL STRATA IN WESTERN LUNGU, TARIM BASIN

The Ordovician strata in Western Lungu, Tarim Basin is considerably eroded by the Early Hercynian uplifting, with well developed palaeokarst. The only outcropped strata are the Middle and Late Ordovician Yingshan and Penglaiba formations, which are controlled by lithology and structure, with capable reservoir and permeation. Based on the analysis of the palaeokarst with the geological background in the area, the forming mechanism and control factors, as well as the capacity of reservoir and permeation, are studied.