开江—梁平海槽西侧飞仙关组不同类型鲕滩储层特征及其控制因素研究

Properties of Different Oolitic beach Reservoirs in the Feixianguan Formation of Kaijiang-Liangping Trough

针对开江—梁平海槽西侧飞仙关组不同类型鲕滩储层特征及主控因素存在较大差异的问题,基于鲕滩沉积演化规律,结合物性与地球化学分析,对研究区储层进行了研究。结果表明:伴随区内飞仙关期高能坡折带不断迁移,对应形成3期鲕滩,发育鲕粒云岩和鲕粒灰岩2类储层,物性及孔隙结构以鲕粒云岩型储层最优,其次为鲕粒灰岩型储层。在鲕滩沉积的物质基础上,轻度蒸发海水诱发的回流渗透叠加深部热液白云石化作用,共同控制鲕粒云岩型储层的形成,而有机酸主导的埋藏期保孔-扩孔作用既进一步改善先期形成的鲕粒云岩型储层,又影响了鲕粒灰岩型储层的形成。该研究对鲕滩储层的差异性成储机理相关研究有很好的借鉴意义。

In view of the significant differences in the oolitic beach reservoir properties and main-controlling factors,physical and geochemical property analyses were used to duty the oolitic beach reservoir of Feixianguan Formation in the western Feixianguan Formation on the basis of oolitic beach sedimentary evolution.Research indicates that the continuous migration of the high-energy slope-break belt in the Feixianguan period results in a development of 3-stage oolitic beaches.There are two reservoir categories,including oolitic dolomite and oolitic limestone.The oolitic dolomite reservoir shows the higher physical properties in more favorable pore structure,followed by oolitic limestone reservoir.Based on the oolitic beach deposition,the oolitic dolomite reservoir development is greatly dependent on the combination of mild seawater evaporation backflow infiltration and deep hydrotherm dolomitization.The pore preservation-expanding effect in the organic acid-dominated burial period not only improves the earlier oolitic dolomite reservoir,but also influence the oolitic limestone reservoir development.This research could provide certain reference for the related investigations on the difference in hydrocarbon accumulation and reservoir mechanisms of oolitic beach reservoir.