Reservoir Characteristics And Comprehensive Evaluation Of The First Member Of Shahejie Formation In Shennan-yuke Area

Shennan-yuke region is located in the southeast of shenxian sag in Jizhong depression of bohai bay basin.The conditions of hydrocarbon accumulation are good in the study area,and Es1 is the important layer which formed the main hydrocarbon source rock in the study area.But the degree of hydrocarbon extraction is low,most of favorable tectonic traps had been drilled,the fault systems are complicated,the heterogeneity of reservoir is serious,the sand horizontal change fast as well as complicated superposition rule,all of these make the geological research more difficult.Therefore,it is necessary to study the Es1 reservoir in shennan-yuke area in detail,which has significance of guiding both next exploration and development.Under the instruction of the rheory of sequence stratigraphy,petroleum geology and other related disciplines,combined with previous research results and resigional geological background,making full use of existing data,such as the drilling coring,logging,seismic data and testing,using the research idea of “ points to lines(from a single well to profile),lines form surfaces(profile to plane),and then planes to space distribution(plane to a three-dimensional space)”to study sedimentary facies,reservoir and related contents are studied,and make prediction about the favorable area.of Es1 in shennan-yuke area.Making comprehensive analysis of logging,cycle characteristics and coring,making preliminary determination about boundary of Es1.Then,observing seismic reflection characteristics by combining well logging with seismic to calibrate the formation interface,esTablelishing the skeleton profile of different wells in the entire study area and dense well area to divide stratum and oil groups.Finally,Getting I,II,III and IV oil groups in Es1.On the basis of analysing of sedimentary facies signs and sedimentary structural characteristics,There are three types of facies:meandering river delta,braided river delta and lake facies.These two delta facies only developed the delta front subfacies,both of them developed five types of microfacies:underwater distributary channel,distributary bay,estuary bar,far sand bar and sheet sand.The lake facies developed the coastal and shallow lake and deep lake subfacies,the microfacies are beach sand,mud and turbidite.Using the core observation,slice identification,oil-bearing and physical analusis to get a result.There are mainly lithic arkose,arkose and feldspathic lithic sandstone of Es1,overall,it has relatively low compositional maturity.Intergranular dissolved pores developed the most,followed by primary intergranular pores in the study area.The main types of throats are microthroat and flaky throat.The pore structure is complex and the seepage capacity is general,Most of the porosity and permeability are of medium-low.The dissolution of Es1 can increase the permeability of pores and throats.As compaction and cementation just reduces the porosity and permeability.The diagenetic stage and diagenetic evolution indicate that the reservoir sandstone of Es1 is in the middle diagenetic phase A period as a whole.In view of the physical property and structural characteristics of the reservoir,by means of k-means clustering method,the five parameters of sedimentary microfacies type,argillaceous content,pore permeability and sand body thickness are optimized to evaluate the reservoir comprehensively in the study area.The reservoir is divided into class I,accounting for 18.9%,class II,accounting for 13.48%,class III,accounting for 16.25%,and class IV,accounting for 51.37%.The zg3 well area of oil group II,ze69 and y15 well area of oil group III,and y15 well area of oil group I are selected as the favorable area of class ?.