Refined permeability of tight gas reservoir based on petrophysical facies classification ——Taking the study of tight gas reservoir permeability in the eastern of Sulige for an example

The tight gas reservoir in the eastern of Sulige is influenced by multi-period sedimentary,diagenesis and structure.And it has small pore space,complex pore structure and complicated log response The reservoir is characterized by heterogeneity and nonlinearity distribution.So petrophysical facies classification can be used for the modeling of permeability in tight gas reservoir in order to determine the various information,division method and classified modeling of evaluating petrophysical facies of reservoir.The interpretation models of different types of permeability parameters which are corresponding to different reservoir petrophysical facies can be established by the use of logging,core and test data in the tight gas reservoir.The distribution fitting of data points in classified models has relatively concentrated distribution trend and a good linear relationship.The classified models which can calculate permeability parameters using the better fitting of density,acoustic,spontaneous potential,natural gamma ray,potassium gamma-rays and thorium and use Hodges-Lehmann method to assess,improve and enhance the accuracy and the effect of tight gas reservoir permeability parameters.It overcomes the characteristics of low signal to noise ratio and low resolution which exist in the tight gas reservoir and provides an effective method to accurately establish the model of the tight gas reservoir parameters.