Distribution Regularity Of Relative High-penetration Of Chang8Reservoir In Zhangjiashan Area,Ordos Basin

Zjs area is located at Tianhuan sag on middle and Yishan slope on west,the Chang-8oil-bearing beds of Up-Triassic Yanchang Formation of signifisance reservoir in the study area.Sedimentary and Diagenesis is studied in the paper through characteristics of sedimentary, Petrological, Diagenesis, Pore structure,development, Penetration and so on to analyze the dis-tribution regularity of relative high-penetration of Chang8reservoir.It illustrates that the reservoir belongs to delta depositional system, has the typical sedime-ntary characteristics of shallow water dalta,full of sand body development. The sandstone with light gray-gray-beige fine particle lithic arkose sandstone and feldspthic sandstone the ov-erall performance shows the characteristics of the lower compositional maturity and the medi-um texture maturity.Chang8reservoir is in late A-early B stage of the middle diagenetic phase at present.The diagenesis is divided into two types:constructive and destructive,and divided into six kinds of diagenetic facies,and chlorite remnant intergranular pore-feldspathic solution facies is the bes-t diagenetic face in he study area. The quantitative research about the pore evolution indicat-es compaction and cementation lose lots of primary pore,but dissolution improve it.There are types of pores, thoats and pore combanitions develop in study area,and it illustra-tes that slit-shaped pores the combination of pore is Significant to reservoir.The capillary pre-ssure curves are devided to four tepys according to main parameters,the Pore structure of the reservoir belongs to â…¢A,less discrepancy level.Based on the the pore structure division level, synthesize the sand-body distribution chara-cteristics, petrological characteristics, and pore structure characteristics, Combined with diagenism facies, fracture development characteristics, oil production test,oil production and other factors, evaluate and predict the reservoir Chang8in the study area comprehensively. Reservoir kind I generally located in the delta front of underwater distributary channel sand body,is of great analogous distribution of chlorite remnant intergranular pore-feldspathic solut-ion facies. Reservoir thickness usually greater than15m,The primary water flooding type is uniform displacement,the result of oil production test greater than8t/d. Reservoir kind I distri-bute wide and continuously in Chang8,and located in the controlling belt ofnorthwestern of the study aera. Chang82distribute dispersedly,and discontinuously,and located in the south-west-northeast in the aera moniliformly.The factors influence the relative high permeability of reservoir are sedimentary microfacies, diagenism facies, pore structure so on. The research suggest that sedimentation and diagenesis effect the formation and distribution of the relative high permeability of reservoir remarkably.All the understanding research above can lay the foundation for the regional exploration and exploitation deployment.At the same time,the law of hydrocarbon accumulation and enrichment in low permeability and ultralow permeability reservoir can be got further understanding.