通南巴地区地层水演化特征及其油气意义

考虑川东北地层水的水化学特征(包括地层水矿化度、地层水的变质程度、脱硫系数等),根据封盖层的发育分布及其内部结构,分析盖层对地层水的分隔性能;结合区域构造演化史,分析地质历史上地表水对地层水的改造程度,研究地层水演化特征.结果表明:通南巴地区地层水主要经历早期深埋形成封存变质水期—局部地层水渗滤改造期—深层水封闭,浅层水进入开启期—晚期重建封闭期等变化;中下三叠统存在一套良好的膏岩层且埋藏较深,没有经历地表水改造,使得保存条件明显优于上三叠统须家河组及中下侏罗统地层,具有较好的保存条件;砂泥互层具有较高渗透能力的须家河组受到地表水的淋滤作用,油气保存条件较差,油气勘探潜力有限.

Tongnanba area formation water evolution characteristics and significance of hydrocarbon

Through water chemical characteristics of Northeast Sichuan formation water(including water salinity of formation water,the degree of metamorphism,desulfurization coefficient),analysis of formation water segmentation performance from the development and distribution of capping layer and its internal structure,combined with regional tectonic evolution history analysis the geological history of surface water on formation water transformation,and then study on evolution of formation water.Evolution characteristics of formation water indicate that Tongnanba area region formation water mainly experienced early deep formation sealing metamorphic water period-Local formation water infiltration transformation period-Deep water closure,shallow water into the opening period-Late reconstruction of closed period of four major stages of change,and points out that the lower three and Upper Triassic due to the presence of a set of good cream strata and deep buried experienced and without surface water transformation process,the preservation conditions are significantly better than the upper Triassic of Xujiahe Formation and Lower-Middle Jurassic,has a good preservation condition,Sand mud interbed with high penetration ability of Xujiahe formation by surface water leaching,the poor preservation conditions of oil and gas,oil and gas exploration potential in finite.