摘要
文中基于钻测井、薄片及地震等资料的综合分析，结合区域沉积构造背景，对川南泸州地区中二叠统茅口组顶部进行岩溶古地貌恢复、动态演化过程分析以及油气地质意义的探讨。选用残厚法恢复茅口组顶部岩溶古地貌，并划分出岩溶台地、斜坡和洼地，以及溶丘、浅洼等地貌单元。结果显示，岩溶洼地地层保存最为完整，岩溶台地普遍剥蚀茅四段、局部影响至茅三段顶部，岩溶斜坡的地层剥蚀程度介于洼地与台地之间。研究表明：中二叠世末，东吴运动引发的地壳抬升促使全区形成泸州古隆起雏形，进而导致区内茅口组地层普遍遭受剥蚀，且剥蚀程度由古隆起核部向两翼逐渐减弱，并由此形成茅口组顶部“北东高、西南低”的古地貌格局；晚二叠世初期，受峨眉山玄武岩喷发影响，龙潭组沉积前的古地貌演变为“西南高、北东低”格局。结合区内油气显示及生产测试资料，指出了岩溶斜坡为最有利的勘探区域。
Abstract
Based on the comprehensive analysis of drilling, logging, thin section and seismic data, combined with the regional sedimentary tectonic background, the karst paleogeomorphology restoration, dynamic evolution process analysis and oil and gas geological significance of the top of Maokou Formation of Middle Permian in Luzhou area are discussed. The residual thickness method is used to restore the karst paleogeomorphology at the top of Maokou Formation, and the karst platform, slope, depression, karst hills and shallow depression are divided. The results show that the strata in the karst depression are most completely preserved. The karst platform generally denudates the fourth member of Maokou Formation and locally affects the top of the third member of Maokou Formation. The denudation degree of the karst slope is between the depression and the platform. The study shows that at the end of the Middle Permian, the crustal uplift caused by the Dongwu movement promoted the formation of the prototype of the Luzhou paleo-uplift in the whole area, which led to the widespread denudation of Maokou Formation in the area. The denudation degree gradually weakened from the core of the paleo-uplift to the two wings, and thus formed the paleogeomorphology pattern of high in the northeast and low in the southwest at the top of the Maokou Formation. In the early Late Permian, affected by the eruption of Emeishan basalt, the paleogeomorphology pattern before the deposition of Longtan Formation evolved into high in the southwest and low in the northeast. Combined with the oil and gas show and production test data in the area, it is pointed out that the karst slope is the most favorable exploration area.
论文详情