Superimposed Rules of Reef-bank Reservoirs in Tazhong Area of Tarim Basin

The reef-bank reservoir was one of the important types of marine carbonate reservoirs in Tazhong Area.In order to systematically analyze the spacial distribution rules of the reef-bank reservoir,the geologic characteristics of reefbank reservoirs in Cambrian-Ordovician of Tazhong Area in Tarim Basin were deeply studied.Based on the core analysis,drilling,logging and outcrop data,the vertical superimposed pattern and lateral distribution for carbonate reef-bank reservoirs were summed up.The sedimentary evolution pattern of reef-bank reservoir was established.A complete cycle was created vertically in the area with rising of sea level,mudstone mound,organic reef,granule bank,dolomite flat was vertically accreted.Multiple reef-bank cycles accumulated reef-bank combination with great thickness was formed.The reef-bank reservoir is mainly developed in highstand system,which has good continuity vertically and poor continuity laterally.The reef-bank reservoirs are mainly developed along the carbonate platform margin in Lianglitage Formation of the upper Ordovician in Tazhong Area.The inter-beach reservoirs are mainly developed in the platform in Yingshan Formation of the lower Ordovician.