四川盆地灯四段岩溶古地貌精细刻画及油气勘探意义

Karst Paleogeomorphology Features of the Fourth Member of Dengying Formation in Sichuan Basin and the Significance of Oil and Gas Exploration

四川盆地震旦系灯四段岩溶古地貌对储集层的发育及分布起到了一定的控制作用。为阐明岩溶古地貌对油气成藏的影响并预测有利油气聚集区域,根据收集的工区内地震、钻井和地质资料,采用了寒武系底-沧浪铺组顶的"印模厚度"同时依据地层厚度的组合关系来准确地恢复震旦系灯四段的岩溶古地貌,并在此基础上将其划分为岩溶高地、岩溶斜坡以及岩溶洼地3个地貌单元,根据恢复的灯四段的岩溶古地貌发现研究区西部发育岩溶洼地,中部发育岩溶斜坡,而东部发育岩溶高地,灯四段整体地貌形态特征为西部凹、中部高、东部低;同时发现具有优质储层的岩溶斜坡为油气最主要的储集区,可作为下一步油气勘探开发的首要目标。

The karst paleomorphology of the four member of Dengying Formation in Sichuan Basin played a certain role in controlling the development and distribution of the reservoir.In order to elucidate the influence of karst paleomorphology on hydrocarbon accumulation and predicting favorable hydrocarbon accumulation area,according to the seismic,drilling and geological data collected in the work area,this article used the moldic thickness from the top of Canglangpu Formation to the base of Cambrian and based on formation thickness relationship to recovery the karst paleogeomorphology of the fourth member of Dengying Formation,and further divided into karst highland,karst slopes and karst depression three geomorphologic units.We can find by karst paleomorphology that in the Western part of the study area,karst depression is developed,and karst slopes are developed in the Middle,karst highland is developed in the East.The geomorphological features of the fourth member of Dengying Formation expressed as west concave,middle high and low in the east.The results also show that the karst slopes with high quality reservoirs are the most important reservoirs for oil and gas,it can be used as the primary goal in the next step of oil and gas exploration and development.