碳酸盐岩礁滩储层的形成和发育规律——溶蚀模拟实验

通过选取不同结构组分的石灰岩样品开展大气水溶蚀模拟实验,结合地质背景认识,总结了碳酸盐岩礁滩储层的发育规律和控制因素。结果表明:(1)碳酸盐岩的岩石组构和孔隙发育状况对岩石溶蚀效率控制明显,颗粒灰岩的可溶性最好;(2)岩相是控制礁滩储层发育和分布的重要因素,礁滩储层选择颗粒岩相发育;(3)初始孔隙度是决定礁滩储层发育程度的关键,它控制了后期溶蚀改造的发生范围,初始孔隙度大小由同沉积期暴露和溶蚀时间两个因素决定。综合研究指出:塔里木盆地塔中地区良里塔格组台内区的勘探应重视后期叠加改造因素的分析,而台缘带开发过程中,应强化岩相、层序界面和同生断裂等因素造成的储层非均质性刻画。

Formation and Development of Reef-shoal Reservoir:Extending Knowledge From the Dissolution Experiment

By means of dissolution experiment of meteoric water on the limestone with different fabric of Upper Ordovician Lianglitage Formation in Tazhong area, Tarim Basin, the developmental pattern and controlling factors of reef-shoal reservoir have been concluded, as following: (1)Rock fabric and primary porosity exert significant effects on the dissolution of reef-shoal rock, in which grainstone tends to be dissolved with highest efficiency;(2)Lithofacies is an important factor controlling the formation and development of reef-shoal reservoir, and mostly for grainstone; (3)Primary porosity, which could be elevated by contemporaneous dissolution and long term dissolution, is essential for the extent of reef-shoal reservoir, and determines the extent of late modification. It is pointed out that attentions should be paid to the analysis on the late superimposed modification during the exploration of Lianglitage Formation in intraplatform zone; whereas during the development of reservoir in platform margin, the characterization of reservoir heterogeneity caused by the combination of lithofacies, sequence boundaries, and syndepositional faults should be highlighted.