塔中Ⅰ号坡折带奥陶系礁滩复合体发育动力学及其控储机制

塔中Ⅰ号坡折带上奥陶统良里塔格组发现了我国珊瑚-层孔虫造礁群落最早的礁体,在生态演替上具承先启后重要特征,并伴随着发育了多套礁滩相储集体。充分利用古地理、古地磁,同位素、微量元素,包裹体,岩心物性分析等数据,分析了塔里木板块奥陶纪成礁环境,特别是从构造地质学、碳酸盐岩地质学、层序地层学、古生态学、古生物学出发,剖析了塔中隆起碳酸盐岩台地演化的阶段性、海平面变化的周期性,以及奥陶纪造礁生物生态群落的演替及生物生长性,分别建立了良里塔格组各个时期礁滩复合体发育的模式,深入解析了礁滩复合体多期生长发育的动力学特征。塔中良里塔格组3期叠加发育的礁体生长与台地演化的构造阶段性密切相关,同时控制了礁滩复合体微相类型上的多样性和分异性。礁滩复合体地貌隆起和高频海平面变化所导致的暴露,以及准同生期大气淡水淋滤、溶蚀作用是控制台缘礁滩体优质储层发育的动力学基础,经后期埋藏过程中所经历的表生岩溶作用、埋藏期热水岩溶作用以及断层相关岩溶等是该礁滩复合体储层物性改良主控因素。集中揭示了塔中奥陶纪礁滩复合体发育演替几何学、动力学机制及礁滩储集体控储机制,有效指导了塔中古隆起奥陶系生物礁油气规模效益开发,对于类似油气田勘探与学科发展具有积极意义。

Kinetics of reef-shoal complexes and its restriction to reservoir in Ordovician from Tazhong I fault belt.

The earliest reef of coralline-coral reef-building communities was developed in the Lianglitag Fm of Upper Ordovician in Tazhong I fault belt. The reef is featured as a role of serving as the link between past and future in ecologic succession, accompanied with developing multi-set of reef-flat facies reservoirs. Making the data of palegeography, paleomagnetism, isotope, microelement, fluid inclusion, core-property analysis etc, this paper analyzes the reef-building environment of Ordovician in Tarim plate, especially focusing on the staged evolution features of carbonate platform of Tazhong uplift belt, the periodicity of sea level change, the succession and bio-growth features of reef-building communities of Ordovician. Consequently, the developing modes of reef-flat complexes in the different periods of Lianglitag Fm are established. The kinetic characteristics of multi-stage developing of reef-flat complexes are analyzed. The reef growth of successive developing of three periods of Lianglitag Fm in Tazhong area is affinitive with the structural staged feature of carbonate platform, meanwhile controlling the diversity and differentia of types of micro-facies of reef-flat complexes. The kinetic foundation controlling the development of high-quality reservoirs in reef-flat complexes in platform edge includes the physiognomic uplift of reef-flat complexes, the frequently variation of sea level and the freshwater leaching through and dissolution of penecontemporary. The surface karstification during the buried process afterwards, the hot-water karstification during the buried process and the kastification related to faults are the main controlling factors in the improvement of the properties of reef-flat complexes. The paper reveals the development of geomorphologh and the dynamic regularity and the reef flat's controlling regularity. Finally, it provides instruction of the scaled development of oil and gas in biogenic reef in the ancient uplift in Ordovician system, Tazhong area.