The Main Control Factor For Oil Rich Integration In Yanchang Oil Field In The Ordos Basin

In recent years,Tight oil has become an important part of resource replacement of Yanchang Oil Field.This paper is based on the core,logging parameters,oil testing data and experimental analysis data,and studies the hydrocarbon source rocks,reservoirs,source reservoir caprock and typical oil reservoirs in the research area,the main control factor of tight oil concentration has been conclusioned.The thickness of hydrocarbon source rocks in the west and south of the Yanchang Oil Field is extended,and it has a wide distribution,regard the“Zhangjiatan”shale of Chang 7 and the“Lijiapan”shale of Chang 9 as a typical,the average TOC of the hydrocarbon source rocks of Chang 7 is up to 6.3%,the kerogen mainly for type I and type II₁,The Ro is between 0.7%and 1.15%.The reservoir storage space is mainly microfissure,corrosion hole and particle hole,the results of the mercury test show that the distribution of the larynx with a length of Chang 6 to Chang 8 has multiple peaks,there are distributions ranging from nano to micron.There are four types of the source storage in the research area,contains self-souce and self-reservoir,thin-layer interbedded,sandwich and neighboring source.The distribution and scale of tight oil reservoir are clearly related to the thickness of hydrocarbon source rocks,the tight oil concentration has the minimum thickness of hydrocarbon source rocks,and the farther away the distance,the greater the thickness of the hydrocarbon source rock of the oil reservoir.The tight oil reservoir distribution in the study area is clearly controlled by the sedimentary microfacies,the tight oil reservoir of Chang 6 and Chang 8 is mainly distributed along the submerged shunt and sheet sand in the leading edge of the delta.The Chang 7 is mainly distributed along the deep lake-half deep lake facies,and the main reservoir is turbidite sand body.The results of the analysis of hydrocarbon source rocks,reservoir,source storage and the oil reservoir profile were analyzed,it was considered that the main control factors of tight oil concentration in the research area are high quality hydrocarbon source rocks widely distributed,the sedimentary facies types,multiple and good source storage combinations and the accumulation-forming model suit for it.