ORDOVICIAN PALAEOKARST LANDFORM AND ITS CONTROL ON RESERVOIRS IN WEST LUNGU REGION, THE TARIM BASIN

Karst landform is the result of the compositive process of karst and various geology.And various shapes of karst landforms also control the karst reservoir development.The palaeokarst landform in west Lungu region was restored by using seismic horizon flattening technique.The results show that the surface of the karst is undulate greatly,and develops the landform combination of peak cluster depression,peak forest valley and peak forest plain from east to west.The vertical karst facies belts in different landform was divided according to the data of well logging,drilling and geological log.Then,the development characteristics of reservoirs in different landforms are discussed.Research results indicate that the great differences of cavern development and filling status exist among various palaeokarst landforms and karst facies belts,which reflect that the palaeokarst landforms control the spatial development of karst facies belt and reservoirs.