Sedimentary Facies And Reservoir Characteristics Research On The Lower Shihezi Formation Of Permian Member 8 Formation In Gaoqiao Area,ordos Basin

Guided by sedimentology and reservoir geology theorys, this Master's degrees paper takes the Lower Shihezi Formation of Permian in GaoQiao area as research subject and discussed it from five aspects such as field profiles, well core, log informations and sample tests. It focus on the combination of macro-observation and micro-analysis, qualitative description and quantitatively compute, systematically arranged and comprehensive improvement, mainly studied the provenance analysis and parent rocks properties, sedimentary system, sand body characters, governing factor of sand body development and reservoir characters of exploration layers in the sudy area. Based on the above jobs, this paper made the following results and understanding:This paper comprehensive analyses the ancient land characteristics along the basin, the clastic rock components characteristics, the cathodoluminescence features and ancient flow characteristics, especially identified the conglomerate components of the cores in GaoQiao area, then ensured that the sediment in the study area mainly come from old metamorphic rock series of Yinshan ancient land and Xing unita fold belt which was formed in Hercynian. Though located in the south of Ordos basin, some cores of GaoQiao area contains conglomerate and pebbly sandstone, the resson is that Siberia plate subduction and push to south, bring about the upraise of northern basin, together with the dry climate, intermittent flood multistage migration the fragmentary material, it also bring about a result that some conglomerate in the south of the study has bigger size than the north.Put Sanchaliang-Tianciwan-Shiwan as boundary, sedimentary environment in it's noreh area is braided delta plain, and it's south area is braided delta front. Paper set up the sedimentary facies model of the study area based on the research of sedimentary facies and microfacies, then analysed the sedimentary framework and sand-body distribution, this thesis thinks that point bat sand body in the braid and mouth bar sand body in the underwater distributary channel is the main reservoir sand body of the the target layer. The thickness of several sand body in the study area reach 30m, mainly formed by the overlay of many phases distributary riverway sand.By means of thin-section analysis, scanning electron microscope materials, mercury penetration and physical property analysis materials, the reservoir heterogeneity of GaoQiao area was studied. Then regard the reservoir of the target layer in the study area as low permeability and low porosity reservoirs, and it's strong homogeneous in plane points was determined by sedimentary facies and diagenesis, vertical points homogeneous was determined by he overlay of sand body and shale content, microscopic heterogeneity was determined by diagenesis.On the basis of above studies about petrological characteristics, Pore throat features, physical property, homogeneous and diagenesis characters, combin with the reservoir evaluation standard of Changqing oil-field, we establish a reservoir evaluation standard which match with Lower Shihezi Formation Member 8 of GaoQiao area. At last, we made a forecast and screen out several favorable areas of the of the target layer in the study area.