A Study On Chang 6 Sedimentary Characteristics And Reservoir In The L Block Of Wuqi Oil Field In Ordos Basin

This paper take the sedimentary petrology,structural geology,petroleum geology as guide.Using the date of core analysis,well logging and oil testing to study fine stratigraphic division and correlation,structural features,sedimentary microfacies,sand body distribution and reservoir characteristics of Chang6 reservoir in the L block of Wuqi oil field.Analysis shows that the Chang 6 oil layer in study area can be divided into Chang 6¹,Chang 6² and Chang 6³.The average thickness of Chang 6¹ is 40⁵0 meters.The average thickness of Chang6² is 36⁴0 meters.and The average thickness of Chang6³ is 45⁴9 meters.Each subgroup formation thickness is relatively stable.The inheritance of the construction is good.The small layer formation of pitching direction roughly from east to west.The terrain is relatively flat.And its decline in the west slope is small.It slightly developm nose-like structure.The overall distribution status to east-west.The distributary channel is the main sedimentary microfacies type.The sedimentary microfacies of the region are mainly subaqueous distributary channel,estuarine bar and shunt bay.The Chang 6¹ sand body is the most developed,It have the best connectivity.And its thickness is the highest in the group.Chang6³ sand body is the least developed,with the least connectivity.The reservoir is mainly composed of fine sandstone and siltstone.Feldspar and quartz content are high in the rock mineral clasp.And debris is less.The degree of separation is moderate-good.The average porosity of the reservoir is 10.43%.And the mean permeability is 2.91×10^-3?m².To some extent,the sedimentary microfacies distribution characteristics control the transverse physical characteristics of the reservoir.And the diagenesis controls the longitudinal physical characteristics of the reservoir.In general,the Chang6 reservoir in L block is a set of low permeability-ultra-low permeability reservoir.