古岩溶地貌及其对岩溶储层的控制——以塔里木盆地轮古西地区奥陶系为例

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

岩溶地貌是岩溶作用与各类地质作用综合作用的结果,不同地貌形态对岩溶储层发育又起着控制作用。以塔里木盆地轮古西地区为例,通过地震层拉平技术恢复了该区的古岩溶地貌,发现研究区岩溶地貌起伏变化很大,自东向西依次发育峰丛洼地、峰林谷地和峰林平原地貌组合。根据测井、钻井、录井等资料对不同地貌区垂向上的岩溶相带进行了划分,并在此基础上,探讨了不同古地貌区岩溶储层的发育特征,结果表明不同古岩溶地貌区、不同岩溶相带中不同类型岩溶储层发育状况存在较大差异,反映了古岩溶地貌明显控制岩溶相带的空间发育,并进一步控制了岩溶的发育。

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.