Study Of Reservoir Characteristics Of Shanxi Formation In Yan513-183 Wellblock,Yan Gas Field

The main gas layer of Upper Paleozoic is shanxi Formation in the yan513-yan183 wellblock of Southeastern Ordos Basin. In this paper,guided by the sedimentology, reservoir geology, based on core, thin sections, particle size cathodoluminescence, scanning electron microscopy(SEM) physical property and testing data, combined with the permeability logging and core analysis data, shan1 and 2 of shanxi Formation has carried on the comprehensive analysis in the study area.Study of the reservoir characteristics,the main controlling factors of the high quality reservoirs has been clear. The main reservoir types in the study area and its effect on the control of the gas reservoir formation and distribution has been clear.Shan1, 2segment of sedimentary facies is meandering river delta front subfacies. The micro-facies is divided into underwater distributary, channel mouth bar and subsea interdistributary bay in yan513-yan183 wellblock. The Reservoir’s rock priority type is lithic quartz sandstone, quartz sandstone taking second place and lithic sandstone least.The main ingredients of interstitial materal is mixed matrix, kaolinite, ferrocalcite and siliceous etc.Shan1, 2 reservoir’s porosity is respectively 4.94%, 5.65% and permeability were 0.67 mD, 2.53 mD. Pore types are mainly secondary solution pores and kaolinite intercrystal pore. Synthesized the factors of reservoir characteristics such as sedimentary facies, reservoir characteristics pore structure, diagenesis, physical properties and testing results, the research is divided into four types of reservoir: Ⅰ class for favorable reservoir;Ⅱ class is more favorable reservoir;Ⅲ class for medium reservoir; Ⅳ class for poor reservoir. This paper consider meandering river point bar developped sand body. Particle size is given priority to with coarse, coarse grain. Quartz content was higher. Porosity and permeability are relatively high. There are conducive to develop high quality reservoirs.Shan1, 2 segment of gas reservoir distribution is controlled by the distribution of reservoir Single sand body thickness>3m.Sand layer lithology is stableand gas reservoir development.Reservoir diagenesis of shanxiFormation has reached the late reservoir in the study area. Porosity and permeability severely reduced. The lithologic trap condition is more complex. Other development of sand body areas controlled by the same facies beltis relatively developed constructive diagenesis(dissolution) in the late diagenesis. The effective reservoir storage capacity significantly increased.