A Study On The Accumulation Law Of Yan 7 And Yan 8 Reservoirs In Yanwu-Sancha Area

The Yan'an formation in Yan Wu oil area of ordos basin is weak in the study of reservoir distribution characteristics,control factors,accumulation rules and patterns,which brings great difficulties to the next exploration and development.Application field of existing data,this paper carried out the study area in geomorphology Yan'an group,structure,sedimentary facies,reservoir and hydrocarbon source rock,hydrocarbon migration channel and power,oil and gas filling period of time,and time limit factor analysis,to determine the objective layer control factors,summarizes the accumulation mode and accumulation rule,which will provide a scientific basis for late oil and gas exploration and development reasonably.According to the geological data of logging,earthquake and core,the sedimentary geomorphology of Longdong area of Ordos Basin is scientifically recovered in terms of Paleogeomorphology restoration in Ordos Basin,combined with comprehensive geological method and impression method.The pre Jurassic paleogeomorphology presents the form of "north slope,zhongzhigou and South highland",and three branch river valleys are developed.Delta plain deposits are developed in the yan8 and 7 layers of Yan'an formation of Jurassic.In the study of the regularity of oil and gas enrichment in Ordos Basin,the paper analyzes the oil and gas accumulation patterns by combining the trap types,reservoir performance and reservoir forming mode.It is pointed out that there are three accumulation modes of oil and gas resources in the basin,the first is the reservoir forming mode of potui on the side of the river valley,the second is the reservoir forming mode in the paleohighland near the river,and the third is the sandstone accumulation model on the inter River Hills,The reservoir forming control factors of Yan'an formation are analyzed.The paleogeomorphology provides the upward migration channel of oil and gas from the source rocks of Yanchang Formation for the lower cut valley,and the good oil storage trap is formed by matching the nose long structure with the channel sand body.