The Study On Sedimentary Microfacies And Reservoir Characteristics Of Wutonggou Formation Of Permian In Sha102Well Block, Shanan Oilfied

Sha102well block in Shanan oilfield is located in the middle of Zhangbeifault-fold belt of eastern uplift in Junggar Basin. Wutonggou formation of Permian isone of the most important productive zones in this oilfield.On the basis of drilling, logging data and other laboratory analysis data, thispaper has carried out a systematically research about stratigraphic division andcorrelation, the microfacies and sand body distribution, reservoir characteristics inproductive zone, using sedimentology, reservoir sedimentology, logging geology asthe theoretical guidance. And it gives a classification and evaluation of the reservoirin order to note the favorable reservoir distribution in the study area for furthereffective development.Referring to previous research, Wutongtou formation can be divided into twosections. And the main reservoir section in bottom is further divided into twosub-members. Combining the information of core and logging cycle characteristics,the second sub-member is divided into two sand sets from top to bottom, and thesecond sand set (P3wt12-2) is further divided into four layers. And the connecting-wellprofile is built for the purpose of clarifying the lateral continuity and thicknessvariation of the formation.After a detailed study of the sedimentary background and sedimentary faciessigns, the southern provenance and fan-delta depositional system are clarified. Themain reservoir section is fan-delta front deposit, and it could be further divided intothree microfacies including underwater distributary channel, channel mouth bar andinterdistributary bay. And this paper analyzes the single well facies, profile facies inorder to give a clear understanding about the plane distribution characteristics ofsedimentary microfacies and sand body.Based on the information of cast thin sections, mercury-injection and other laboratory information, this paper studies the characteristics of rock, pore, porosityand permeability. The medium-fine lithic sandstone and feldspathic lithic sandstoneare common in the reservoir section, and they have low compositional maturity. Themain types of pore are remaining intergranular pore, intragranular dissolved pore andintracrystalline pore. They have moderate displacement pressure and connectivity.And based on the data of physical properties, the reservoir has moderate porosity andlow permeability.The paper also studies the in-layer, interlayer, planar heterogeneity, and give ananalysis of the controlling factors of reservoir physical properties.In the end of the paper, it establishes a classification criterion used integratedfactors including reservoir characteristics, sedimentary facies and sand bodydistribution characteristics. The reservoir is divided into three categories.Level Ⅱ with good physical properties andlevel Ⅲ with poor physical properties aremost common in the research area. Level Ⅲ is located in the edge of the sand body.Level Ⅱ with large scale and good physical properties is in the mainunderwaterdistributary channel of the study area, located in the central and eastern part. And ithas good exploration potential.