The Research On Sedimentary Facies And Reservoir Characteristic Of Shanxi Formation-Lower Shihezi Formation,Fuxian Area, Ordos Basin

Fuxian area is located in the southeast of Ordos basin, areal structure located inthe southeast of northern shanxi slope. shanxi formation-lower shihezi Formation ofis the object of this paper. Based on the study of drill sample,thin sectionanalysis,well logging data in the past one yeas,Use all kinds of modern theory andtechnique, comprehensive and systematic clear and Stratigraphic division of theshanxi Formation and the lower shihezi Formation. Uniting stratigraphic divisionscenario and building stratigraphic division framework. pointed out the types of faciesis transitional facies in research area.Describes the development characteristics and spatial and temporal distributionof depositional systems, establish a depositional model in research area.For the first time through a variety of source analysis methods, specific to criticalperiod for the source analysis for the the Fuxian region and its adjacent in shanxiformation—lower shihezi Formation.The results show that the late Paleozoicprovenance tectonic setting of the nature of the orogenic belt and then cycle.Anddetrital material come from the sedimentary rock or metamorphic rocks whose nativerock is sedimentary rock.there are three main source areas in the southern Basinregion.Systematic draw up the corresponding lithofacies paleogeographic map.For theoil and gas exploration provides important foundation and discusses thepaleogeographic evolution.Integrated on the the rock characteristics, pore type and structure，theirinteraction law of Fuxian region that：Shanxi Formation and low shihezi Formationsandstone is mainly medium-coarse sandstone, the rock type is mainly quartz sandstone, lithic quartz sandstone, lithic sandstone, interstitial material structure typeis mainly matrix-cement mixed interstitial,the main cement type is pore cementation;Diagenesis have the following five categories: compaction, cementation,metasomatism, pressure solution and dissolution, which dissolution is most favorableto the formation of secondary porosity. Target layer sandstone pore types as follow:dissolution pores (Dissolution intergranular pores, dissolution of particles within thehole, molded hole), intergranular porous, residual intergranular pores and microcracks; statistical results from the layers of Fuxian area show that porosity of average6.9%in low shihezi formation1st section, maximum17.4%, average permeability0.265mD, the maximum1.181mD,they are better than the other layers, Shanxiformation1st section degree of porosity is equal with shanxi formation2st section butpenetrability poor; the whole study area reservoirs are low porosity, low permeabilitytight reservoir porosity and permeability relationship is poor; sedimentary facies,diagenesis of the reservoir properties is the most important control factors.On the basis of Shanxi Formation-Lower Shihezi Formation of the Ordos Basinthe Fuxian region, sedimentary characteristics and the study of paleogeography, toconsider on the basis of the analysis of the diagenesis, structure and reservoirproperties, combined with previous studies and the current exploration situation,pointed out the favorable exploration in terms of stratigraphy, sedimentary facies,reservoir lithology.