摘要
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.
Through the comprehensive study of the texture-genetic classification, diagenetic manners and evolution stages, trace element characteristics of Fe, Mn, Sr, and isotopic geochemistry characteristics of C, O and Sr of Feixianguan Formation, Lower Triassic in Northeast Sichuan, four diagenetic systems were divided in the dolostone of Feixianguan Formation according to ＂hydrological system＂, which were pore brine of the penecontemporaneous stage, compaction hot brine of the early and middle diagenetic stages. The character and source of dolomitic fluids of various diagenetic stages and system had certain familiarity and inheritance features of development and evolution, but the interaction process between fluid and rock, diagenetic manners and characteristics of product and assemblage were different respectively. So the diagenetic systems and manner of diagenesis, which are related to the reservoir development closely, are mainly the burial dolomitization and dissolution of multiple-stage. According to the temporal-spatial accordance and matching relations of reservoirs and oil-gas accumulations in different diagenesis systems, four controlling factors of high-quality dolomite reservoirs were concluded： （1） the regional distribution and size of reservoirs were controlled by oolitic shoal microfacies; （2） high-quality reservoirs were based on the burial dolomitization of early and middle diagenetic stages; （3） the distribution of reservoirs was expanded and their quality was improved by burial dolomitization of the late diagenetic stage; （4） tectonic disruption, TSR and dissolution were the key to forming highly-efficient oolitic shoal gas reservoir which contained acid gas rich in H2S and CO2.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2011年第4期659-669,共11页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金项目(Nos.40672073
41002033)
关键词
白云岩储层
成岩作用
地球化学
成岩流体
成岩系统
dolomite reservoirs
diagenesis
geochemistry
dolomitization fluid
diagenesis system.
