Study On Sedimentary And Reserviors Of Sand-conglomerate Bodies In Shahejie Formation About Bonan North Actic Region

In this paper,using the seismic data,logging data,core data,property data,oil testing data and other data,based on sequence stratigraphy,sedimentology and reservoir geology theory,the sequence stratigraphy,sedimentation and reservoirof glutenite bodies of Shahejie formation in the North Zone of Bonan Sag have been studied.According to the study,the sequence stratigraphic framework was established.The genetic types,the vertical evolution and the plane distribution of the glutenite body were clarified.The basic characteristics of sand conglomerate reservoir,the controlling factors of physical property and the formation mechanism of high quality reservoir are clarified.This thesis achieved the following understandings and results:Shahejie Formation(Es3-Es1)of the North Zone of Bonan Sag was divided into three third-order sequence.The sequence structure has the characteristics of "two parts".There are two structure types of fan among the sequence in steep slope zone: the retrogradation fan and retrogradation-prograding fan.With the analysis of tectonic-lake level,the evolution of the fan among sequence have been studied and sedimentary model have been established.There are two kinds of glutenite body: retrogradational neritic subaqueous fan and progradational fan delta.There are different in rock types,grain size,sedimentary structure,well logging facies,seismic facies.Sequence?deposited neritic subaqueous fan.Sequence?and sequence ? period roughly deposited neritic subaqueous fan early and fan delta later,but some other wellblock still deposited neritic subaqueous fan later.the sedimentary models have been established.The rock type of reservoir was mianly inclued feldspathic lithic sandstone and lithic feldspar sandstone.The main diagenesis included compaction,cementation,metasomatism and dissolution.The reservoir was in the early diagenetic B-middle diagenetic stage A2.The reservoir spaces included primary intergranular pores,intergranular pores,intragranular dissolved pore and moldic pore.There were four abnormal high porosity zones in the reservoir physical properties.The first is mainly primary pore,but the second and third is mainly vuggy porosity.The best reservoir property is in west,central secondly,east third.The reservoir physical parameter was mainly controlled by sedimentation and diagenesis.Different diagenetic evolution of sedimentary microfacies caused the finaldifference ofreservoir properties.The high quality reservoirs was mainly developed in the subaqueous distributary channel and the mouth bar of the fan delta front and the braided channel in the nearshore subaqueous fan.