The Permian Maokou Formation in southern Sichuan Province is a set of thickly stable bio-clastic limestone with dense and brittle matrix. The Dongwu Movement of the late Middle Permian leads to the development of the palaeoweathering crust-type karst on the apex face of Maokou Formation in this area. Palaeokarst water system controls the development and evolution of the palaeokarst. After studying the methods of recovering palaeogeomorphology, this paper analyzes all kinds of data to recover the palaeo-geomorphology with impression method and researches the characteristics of the palaeokarst water system.On this basis, four second order landform units, such as karst platform, karst abrupt slope, karat gentle slope and karst basin and ten third order units, such as hill depression, karst trough valley and peak forest basin are subdivided, combined with eroding features of the upper surface, properties of sediments, configuration of geomorphology and data of drilling well and seismic. At last, the karst features of each u-nit are analyzed. So the research findings will provide reliable target for the reservoir predication in the next step.%蜀南地区茅口组为一套沉积稳定的巨厚层生物碎屑灰岩,基质致密性脆.中二叠世末的东吴运动使蜀南地区茅口组顶部发育古风化壳岩溶,古岩溶地区水系控制着古岩溶的发育和演化.在研究古地貌恢复方法的基础上,分析研究区地层特征和区域构造背景,采用印模法进行古地貌恢复,进而研究了古岩溶地区的水系发育特征.在此基础上,结合风化壳表面侵蚀溶蚀特征、沉积物性质、地貌组合形态、钻井和地震资料,把研究区划分为岩溶台地、岩溶陡坡、岩溶缓坡及岩溶盆地4种二级地貌单元和溶丘洼地、岩溶槽谷、峰林平原等10种三级地貌单元,进一步分析了各种地貌单元的岩溶特征,为下一步的储集层预测提供了有利的目标.
展开▼
