The Study On Sedimentary Fades And Reservoir Characteristics On Yan9Oil-bearing In Northern Shaanxi

As one pirmary oil-bearing seires of Ordos Basin，Jurassic Yan丨an Formation Basin ofJingbian located in the middle of the slope possesses a great exploration potential? because thestudy of it is on the low level. The purpose of this paper which mainly reaserch on Yan9reservoir of Yan’an formation in Jingbian Cao Yaoxian area is providing the geological basisfor increasing reserves and production. This study also has important guiding signiifcance forexploration and development of oil and gas in other areas of northern Shaanxi slope.This paper gives the details of strati graphic division and sedimentary microfacies by acombination of sedimentology and logging geologyusing core analysis data, logging andlogging date. In ihe the guide of reservoir geology theory and complementary research methods,it takes a systematic and thorough study into the area Reservoir rock characteristics,physicalfcatures,pore structure characteirstics, heterogeneity characteristics and reservoir classificationand evaluation of Yan9by using laboratery analysis data,The study shows that: Yan9oil reservoir of the study area was subdivided into Yan9jand Yan97； The study area is meandeirng river deposits which can be Identiifed channelmicrofacies.flood plain microfacies,crevasse channel microfacies and Natural levee; The mainreservoir sandstone are feldspathic quartz sandstone having characteristics of medium—bettersandstone sorting and medium roundness in the mass; Interstitial content reach15.3%whichmainly are the ccment having pore cementation of cementation type; The porosity of the studyaera*which mainly are original intcrgranular pore of Gap types, is mainly distirbuted between11%to14%and the penetration ranged from7X10"32^m to13X l(y32|im;The distribution ofporosity and permeability is closely related to sedimentary microfacies and sand bodydistribution; Yan9oil reservoir of the study area is weak speed-sensitive, medium-weakwater-sensitive, weak salt sensitivity，moderate acid sensitivity and weak base sensitive Byusing laboratery data; Through analysis by synthesis,The reservoir can divided three types.Themain type of every reservoir is type II.