Research Of Reservoir Characteristics And Controlling Factors In Feixianguan Formation In Tieshan-shuangjiaba,Northeastern Sichuan

This paper selects the reservoir of Feixianguan Formation in Tieshan-shuangjiaba Area in Northeast Sichuan as the research object,on the basis of previous studies, the theory of modern sedimentary geology and petroleum geology,guided by modern sedimentary geology and petroleum geology theory, the existing results are collected, analyzed and summarized,combined with field survey, core observation and logging data, test analysis data,comprehensive stratigraphic boundary division and sedimentary microfacies and facies characteristics of the Changxin Formation.Through in-depth study of reservoir characteristics, the main controlling factors of reservoir are further analyzed,in order to provide geological basis for the exploration of new favorable exploration blocks.1.First comprehensive utilization of outcrop, drilling core and cuttings petrology, paleontology, tooth shaped stone, well logging and seismic various means of the Changxing and Feixianguan formation boundary defining division,a new stratigraphic division scheme was supported by the first sp. Hindeodus dental stone,the new stratigraphic division accords with the sedimentary pattern and oil and gas exploration in the west side of the trough;the formation of the five cycles of the flying fairy off group has the characteristics of the southwest thin and the Northeast thick formation.2.On the basis of phase analysis, the studying area is divided into evaporation platform, restricted platform, open platform, platform margin, platform front edge slope and other facies belts,and further to the subfacies and microfacies analysis of classification and characteristics, understand the Feixianguan formation plane of distribution.3. Reservoir rocks in Feixianguan Formation mainly deposited dissolve hole residual oolitic dolomite, sparry dissolved porous oolitic(arenaceous) limestone, crystalline dolostone,the reservoir space is mainly intergranular, intergranular dissolved pore, intercrystal dissolved pores,the pore size is smaller than that of 0.2mm,main cracks in the structure,which can be used as an important flowing channel,the pore throat is dominated by the throat, and the difference of the structure parameters of the pore and throat is larger;the reservoir is generally in low porosity and low permeability reservoir.4.The Feixianguan reservoir is controlled by oolitic beach, dissolution and dolomitization and deposited oolitic beach in Taidi, Taidi margin constitute facies,the dolomitization near the surface is the key to the formation of high quality reservoir,dolomitizing fluids is from F-4 deposition before the end of the sea,the heat convection circulation provides the power source for the near surface Baiyun Petrochemical fluid circulation,the distribution of reservoir is enlarged by the late dissolution,structural fracture increases the flow capacity of reservoir.Oolitic beach, dissolution dolomitization is the most important factor for a high and stable yield in Feixianguan Formation.