四川盆地二叠纪玄武岩喷发事件的油气地质意义

基于四川盆地二叠纪玄武岩喷发事件,在众多前人研究成果的基础上,详细研究玄武岩的时空分布特征,分析玄武岩喷发事件的油气地质意义。结果表明,峨眉山玄武岩垂向上具有多旋回的特征,最多可识别出10~11个旋回;平面上不仅在川西、川南大面积分布,在川东北也有分布。玄武岩油气地质意义表现在:玄武岩经过后期改造发育有效储集空间,可以构成油气储层;玄武岩喷发前玄武岩浆呈柱状上侵过程中形成的隆升系统,对后期的生物礁和颗粒滩沉积体系的发育创造了有利条件,并为下二叠统茅口组古岩溶储层发育创造了条件;隆升同时发育拉张系统,为下伏茅口组灰岩白云岩化深部Mg~(2+)来源提供了运移通道;二叠系含油气系统的形成亦受控于此。

Geological significance of oil and gas in the Permian basalt eruption event in Sichuan Basin,China

The eruption event of Permian Emeishan basalt,the temporal and spatial distribution of basalt in the Sichuan Basin and its geological significance of oil and gas are studied and analyzed.It shows that the Emeishan basalts develop as many as 1 0 to 1 1 erupting cycles in vertical direction and distribute in the west, east and northeast Sichuan Basin. After the formation of basalt, the subsequent reformation of basalt leads to the development of effective reservoir space and formation of oil and gas reservoir. The column uplift of basalt magma provides favorable condition for the formation of late stage reef and beach as well as for the development of karst reservoir in the late Permian Maokou Formation.The extension system accompanied the basalt magma uplift provides migration channel for the deep Mg2+ which causes the dolomitization of limestone,and controls the oil and gas systems of Permian in Sichuan Basin.