Research On Oil And Gas Reservoir Formation Law Of PuTaoHua Oil Bering Layer In PuXi Area

With the development of the exploitation of the western peripheral area of Daqing oil field, it is more and more difficult to use the mothball reserves,so that the exploitation of the low permeability reservoir that representative by Puxi oil field becomes the main exploitation object at present. This kind of oil reservoir keeps more abundant resource, but because of the thin reservoir, bad physical property and unstable development,it is difficult to control the reservoir characteristics and drilling technology , simultaneously , because of the argilliferous, calcareous and thin of the reservoir, multiple types of fluid and complexity of the oil and water relationship, it is difficult to recognize the electric nature of the oil and water and made the low coincidence rate of the interpretation of the oil and water layer. So,in this paper we based on Puxi oil filed tudied the formation law of oil and gas reservoir. This research analyses the sequence stratum framework,the sedimentary facies,the reservoir,the oil gas pool distribution rule,the controlling factors and the stratum - lithological trap of Putaohua oil bearing layer in Qiqia– Gulong area in northern Songliao basin ,comprehensively based on the newest theory and the method of sequence stratigraphy,sedimentology,seismic stratigraphy and reservoir geology,and using the data from seism,logging,geological log and core.This research divides the Putaohua oil bearing layer into three fourth-order sequences ( they are SQ1,SQ2,and SQ3 upwards ) (equal to the lowstand systyms tract and transgressive systems tract of sequenceⅩⅣin Songliao basin),using the data from core,seism,logging as well as examination analysis,and divides the fourth-order sequences into three systems tracts ( they are lowstand systems tract,transgressive systems tract and high systems tract ).Based on the above research on sequence stratigraphy,make use of the drill core, mud logging, logging and seismic materials,we do research on the deposit systems of Putaohua oil layer in Puxi oil field,make certain that Putaohua oil layer in Puxi oil field mainly develop delta front intrafacies,main microfacies types are subaqueous distributary channel, lie in distributary channel, mouth bar and sand sheet, because sand body of reservoir distribute discretely, sand body distribute as short strips,moniliformiy and lenses discretely. Sand body connectedness is bad on vertical,heavy clay content. We make certain that this is typically"mud pack sand"deposition type.Though tectonic history research,accumulation of oil and gas history research, history of the evolution of hydrocarbon source rocks,diagenesis of the matrix and so on, we can reveal the complex geology causes of this area 's distribution of oil and gas main control factors.tectonic history research shows that the area of early tectonic movement were very good match with substantial source rock generation and expulsion period of time of Qingshankou, and the late tectonic movement of the reservoir made the early formation destruct and re-distribut the oil and gas.Study of the history of fault development shows that early faults were channels and blocks to the oil , but advanced fault damage the reservoir.Diagenesis studies show that at the end of Nenjiang, shale dehydration period of time coincided with the substantial oil-generating time at the qingyiduan, it is the carrier or power of primary migration of oil and gas , while in the end of Mingshui the structure on the nose gather lots of oil and gas , the large number of reclaimed water from which mudstone express extrusion make the reservoir destruct enormously. At the same time, analysis the abnorma high pressure impact on accumulation.On the basis of the study of the deposition and accumulation research we can predict favorable blocks in Puxi Area, this can provides a solid foundation for development of the oil into a large area.