Reservoir Characteristics And Favorable Belt Prediction Of Sha-3 Member In Gaoliu Slope Belt In Nanpu Depression

Along with the exploration work in Gaoliu area in Nanpu depression,the exploration of structural reservoirs and the obvious structural trap has been carried on,and the direction of oil and gas exploration is turning to subtle reservoirs which is mainly composed of lithologic trap and stratigraphic trap.The study is on the basis of core observation,logging data,test and analysis,and predecessors'research.Based on the application of sedimentary petrography,reservoir geology,geophysical well logging and other theory and method,we carry out the research of reservoir characteristics and high quality reservoir controlling factors,and predict the favorable zones in Gaoliu slope belt.The main achievements and cognition of the thesis are as followings.1.Rocks of Sha-3 Member in the study area are mainly lithic arkose and feldspathic lithic sandstones,with low compositional maturity and structural maturity.The reservoirs are primarily medium porosity medium permeability to low porosity low permeability ones.Reservoir space is mainly secondary pores,which mainly include solution pore and fracture.Pore structure can be divided into four types,and type I and II are better reservoirs with a low displacement pressure.2.The reservoirs of Sha-3 Member in the study area are in the middle diagenetic stage.Reservoir rocks mainly experienced mechanical compaction,pressure solution,cementation,metasomatism and dissolution.Constructive diagenesis includes dissolution and chlorite cementation.Compaction.Destructive diagenesis includes compaction-pressure solution,carbonate cementation and siliceous cementation.3.The sequence stratigraphic filling and superimposed style and the distribution of sedimentary microfacies in the sequence framework determine the development and distribution of reservoir sand bodies.The underwater distributary channel sandstones developed in the datum plane transition from down to up are the main reservoir sand bodies in the region.4.High are mainly distributed in the sandstones?oil group III,IV,V of Es₃³?above the water flooding mudstones?Es₃⁴?in SQ2.The level of oil and gas in fourth-order sequences close to unconformity surfaces?top of Es₃² and Es₃¹?takes second place.The statistics of oil and gas sedimentary genetic types shows that oil and gas ratio from high to low is:front distributary channel sand,plain distributary channel sand,front far bar,lacustrine sand dam and other types of sandstones.5.On the longitudinal,sand body position in the sequence stratigraphic framework and diagenesis control the reservoir quality and the distribution of favorable reservoir.On the plane,the distribution of favorable reservoir sand bodies is mainly affected by sedimentary origin,spatial distribution of sand bodies and tectonic position.On the comprehensive research of the above analysis,7 layers enriched in reservoir sand bodies in relatively good quality and 4 kinds of favorable reservoir facies belts can be identified in the study area.