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通过对川东北地区下三叠统飞仙关组白云岩的结构-成因分类、成岩作用方式、成岩演化序列和铁、锰、锶微量元素,碳、氧、锶稳定同位素地球化学特征的综合研究,从盆地大尺度的成岩作用组合特征出发,按“水文体制”将飞仙关组白云岩划分为4个成岩系统:(1)准同生阶段孔隙卤水成岩系统;(2)早-中成岩阶段地层压实热卤水成岩系统;(3)晚成岩阶段混合热卤水成岩系统;(4)构造隆升阶段油田热卤水成岩系统.各阶段成岩系统白云化流体性质和来源具有一定的亲缘性和继承性发展演化特点,但水-岩相互作用过程、成岩方式、产物和组合特征各不相同,与储层发育密切相关的成岩方式主要是各成岩系统中的多期次埋藏白云化和溶蚀作用.根据各成岩系统中成岩作用与储层在时间-空间上的耦合与匹配关系,可将优质白云岩储层和油气藏控制因素归结为3点:(1)早-中成岩阶段埋藏白云化为储层发育基础;(2)晚成岩阶段埋藏白云化扩大,提高了储层分布范围与质量;(3)构造隆升阶段破裂、TSR和溶蚀作用是形成飞仙关组高效气藏的关键.
Based on the structural-genesis classification, diagenesis, diagenetic evolution sequence and trace elements of iron, manganese and strontium, the stable isotope geochemical characteristics of carbon, oxygen and strontium in the Feixianguan Formation of the Lower Triassic in northeastern Sichuan Based on the large-scale diagenetic assemblage characteristics of the basin, the dolomites of Feixianguan Formation are divided into four diagenetic systems according to “Hydrological System ”: (1) Porphyry diagenesis diagenesis system; (2) Early- (3) diagenetic system of mixed hydrothermal brine in late diagenesis stage, (4) thermal diagenetic diagenesis system of oilfield in uplift stage of the diagenetic stage.The dolomitization fluid of diagenetic system in each stage has certain relatives But the characteristics of water-rock interaction, diagenesis, product and assemblage are different. The diagenetic methods closely related to the reservoir development are mainly the multi-stage burial dolomitization and diagenesis in various diagenetic systems According to the coupling and matching of diagenesis and reservoir in space-time, the control factors of high-quality dolomite reservoirs and reservoirs can be summarized as follows: (1) Early-middle diagenetic (2) burial dolomitization in late diagenesis stage, which can improve the range and quality of reservoir distribution; (3) TSR and dissolution are the key factors in the formation of Feixianguan Formation high efficiency The key to gas reservoir.