四川盆地中部龙王庙组储层成岩作用

摘要

At present,the Lower Cambrian Longwangmiao Formation in the central area of Sichuan Basin is one of the most important reservoir rocks for oil and gas exploration.According to the analysis of the core and logging data, core observation, thin sections, casting sections, cathodoluminescence,carbon and oxygen isotopic data and major elements data,this paper studies the diagenesis of the Longwangmiao reservoir rocks.The results show that the granular dolomite and the crystalline dolomite are the main reservoir rocks,and there is constructive diagenesis,destructive and retentive diagenesis in Longwangmiao Formation.The constructive diagenesis includes corrosion, fractures and hydrocarbon filling, the destructive diagenesis includes compaction and pressure solution,and the retention diagenesis includes cementation,dolomitization and micritization.This paper reveals that the grain beach microfacies is the prerequisite of developing the Longwangmiao Formation high-quality reservoirs,and the seawater dolomitization,penecontemporaneous fresh-water dissolution and hydrocarbon (organic acids ) filling are the key factors to form the high-quality reservoirs.%四川盆地中部地区下寒武统龙王庙组是油气勘探研究的重点层位。根据钻井资料、测井数据、岩心观察、普通薄片、铸体薄片、阴极发光、碳氧稳定同位素和主元素等分析，对龙王庙组储层成岩作用进行了研究，结果表明为颗粒白云岩和晶粒白云岩是龙王庙组主要的储集岩性，成岩作用主要有建设性、破坏性和保持性。建设性成岩作用主要包括溶蚀、破裂和烃类（有机酸）充注作用，破坏性成岩作用主要包括压实和压溶作用，保持性成岩作用主要包括胶结、白云石化和泥晶化作用。揭示了颗粒滩微相是龙王庙组优质碳酸盐岩储层发育的基础条件，海水白云石化、准同生期淡水溶蚀和烃类（有机酸）充注作用是优质储层形成的关键因素。