The Research On Reservoirs Characteristic Of M5_1-2 Carbonate Reservoirs In Shenmu-Yulin Field Ordos Basin

Shenmu-Yulin region is located in the northeast of ShanBei slope of Ordos Basin.The study area is about 7120km² but only have 95 exploration Wells because of low degree prospecting.Because the upper Paleozoic ordovician MJjiaGou group of carbonate reservoir geology situation is complex and has different reservoirs characteristics compared with Jingbian gas field and Sulige gas field in Ordos Basin,it's difficult to meet the present geological understanding of the practical need of exploration and development.This paper reveals the reservoirs characteristic from three aspects: the characteristics of karst reservoir,The characteristics of diagenesis,the characteristics of reserved.It is different from traditional reservoir characteristics research,because the author is based on the perspective of exploration.This paper is guided by theories and technology methods of Sedimentology,Reservoir Geology,Karst Geology and so on.Connected with the predecessors research results and indicated by comprehensive data analysis of well logging,mud logging,core,cuttings and some production materials.The paper studies stratigraphic classification and the structural of the small amplitude of MaJiaGou formation in the studied area.This paper has made clear the sedimentary microfacies distribution and the ordovician palaeokarst landform through core observation,thin section identification,cathodoluminescence and scanning electron microscopy,combination of macro and micro.Focused on permeability using carbon and oxygen isotope strontium isotope determination of high pressure mercury injection package cervix temperature and so on the many kinds of experimental test and analysis,the study of reservoir characteristics.The main conclusions are as follows.The research area of M5₁,M5₂ is characterized by rock types in mud-powder crystal dolomite powder-fine crystalline Gladstone Gray matter YunYan and sacrilegious YunYan primarily.Compared with Central basin JingBian-YanShuiGuang gas field,this area ' s sedimentary period is relatively deep water and impacted by weak evaporation environment.The supranational cream quality sets only by M5₁³ small layers in the five development,other small layers mainly set and tide gray matter set according to given priority.the article researches on the each zonal distribution which from horse M5₂² small layer up to M5₁¹ small layers,expanding set on the tide and its tided on gray set shrinking;Supranational mud set and second development tides are lied on the mudflat of cloud and ash on plateau which are distributed in the study areas on an small layer of island,but the development scale has slightly difference.The reservoir karstification has strong solution and its erosion groove relative has developed.Analyzed of the strontium isotope,affected by atmospheric fresh water leaching,the main development of supergene karst,the second stage for burial karst and syngenetic karst,syngenetic period karst is mainly affected by sea level changes.Strong karstification is not only improving the reservoir property,and caused by region is given priority with karst basin.The karst slope exists only in the study area of northwest edge.The karst slopes develops in monadnock,depression,slope and groove.The Karst basin?quasi?plain is mainly developed by monadnock and grooves.The reservoir diagenesis has various types which has reservoir important role of development and the cemented filling is effected by dolomitization and dissolution.It is mainly affected by the atmospheric fresh water and burial diagenetic environment,the water diagenetic environment have little affection.The temperature of diagenetic is between 87.35 143.80 degree centigrade,the temperature of diagenetic intensity is between 49.03 95.50 degree centigrade.The reservoir permeability space is mainly made by Intergranular dissolved pore cave,filling residual hole,die structure seam and soluble seam.The mainly reservoir type is pore type and fracture pore type.Influenced by lysis and diagenesis.The reservoir physical properties of M5₁ is better than M5₂.The M5₂ has better porosity and Permeability.The permeability size iscontrolled by porosity development degree,but the more important aspect isconnected with state and fracture porosity development.