蜀南Z工区茅口组顶岩溶古地貌、古水系特征与刻画

蜀南地区茅口组灰岩岩溶储层较为发育，是蜀南地区重要的产层之一。但是该套储层非均质性强、缝洞充填程度高，储层预测具有较大困难。恢复岩溶古地貌、刻画古水系，可以摸清岩溶储层的发育分布规律，对蜀南地区茅口组油气勘探具有重要的指导意义。本文利用印模-趋势面法，以茅口组顶至长兴组顶的沉积厚度为标识，恢复了蜀南Z工区的岩溶古地貌，根据微地貌组合形态，划分了4类三级地貌单元，并结合岩溶水文地质学理论在Z工区刻画出南北向地表水系。分析认为不同的地貌位置，水动力条件具有较大差异；河流两侧位于径流区，水动力条件最强，溶蚀孔缝最发育，是下一步储层勘探方向。 

Characteristics and characterization of karst paleo-geomorphology and paleo-water system on the top of the Maokou formation in the Z area in southern Sichuan basin

The limestone karst reservoir of Maokou formation in southern Sichuan is relatively developed， and it is one of the important producing strata in southern Sichuan. However， the reservoirs has strong heterogeneity and high degree of fracture-cavity filling， which makes it difficult to predict reservoirs. The recovery of karst paleo-geomorphology and paleo-water system can help us to master the development and distribution of karst reservoir， which is of great significance for the oil and gas exploration of the Maokou formation in the southern Sichuan basin. In this paper， the karst paleotopography in the Z area in southern Sichuan basin is restored by the impression-trend surface method with referring sediment thickness form the top of Maokou formation to the top of Changxing formation. According to the micro-geomorphic combination form， four kinds of three-level paleogeomorphology are divided， and the north-south paleo-water system is depicted according to the theory of karst hydrogeology. The analysis shows that the hydrodynamic circumstance is quite different in different geomorphologic locations. The both sides of the fluvial are located in the runoff area， with the strongest hydrodynamic conditions and the most developed dissolution pores and fractures， which is the next reservoir exploration direction.