Reservoir Diagenesic-oil Accumulation Coupling Relationship Research Of Fuyu In San Zhao Depression Songliao Basin

This paper is based on the logging,core,rock slice,cathodoluminescence,SEM,homogenization temperature and fluorescence characteristics of fluid inclusions,the study combined with previous research results,and the burial-thermal evolution history of the basin.As resaults,the diagenesis and diagenetic sequence of the study area are summarized,the contribution of different diagenesis to reservoir is studied,as well as the compact history and the oil & gas accumulation history is restored.The main conclusions are listed as follows:(1)The clasticrock are mainly lithic arkose and lithic sandstone,the ingredient of the cements was complex,including the muddy sediments,calcspar,illite,kaolinite,chlorite and silica.According to the analysis of diagenesis,the diagenetic stage basically entered in the middle diagenetic stage A.The diagenetic sequence is:The compaction effect?Early chlorite?Early calcite?Stage? quartz overgrowth?Stage? quartz overgrowth?The dissolution effect?Advanced calcite?Illite ring edge?Oil & gas accumulation.The reservoir has been in a dense state before hydrocarbon charging.(2)The study established two different diagenetic evolutionary sequences : “Middle of the sand body” and “Calcic sand”(the bottom of the sand body which is rich in carbonate cement).Cementation is the main cause that makes reservoir tight of the “Calcic sand”.Compaction is the main cause resulting in the disappearance of porosity at “Middle of the sand body”.(3)By calculating that the reservoir has became tight at the late Nenjiang series,oil & gas mainly accumulated at the late Mingshui series,the oil & gas accumulated after the tight of the reservoir.