Experimental Study On Reservoir And Flow Characteristics Of S Tight Reservoir

Tight oil has gradually become a hot spot and focus on the field of unconventional oil and gas resources in China.The study of the physical properties and seepage mechanism of the tight reservoir is the basis of the scientific development of the tight reservoir.In a tight sandstone reservoir,the substantial heterogeneity,the development of dissolution pores and microfractures lead to tight lithology,low porosity and permeability,and complex oil-water micro seepage mechanism.There are few studies on the quantitative study of reservoir heterogeneity by using the fractal geometry method.Therefore,this paper studies the physical properties and percolation mechanism of the S tight reservoir.Combining theory and experiment,aiming at the situation of the tight reservoir,studies the pore structure characteristics,fractal dimension,and seepage mechanism that have essential theoretical and practical significance for the scientific development of the reservoir.The main achievements are as follows:The experimental method studied the regional geological characteristics,reservoir plane distribution,heterogeneity characteristics,porosity,permeability,and mercury removal efficiency of S tight reservoir.The reservoir petro-logical characteristics and pore structure types are analyzed to provide a theoretical basis for the study of reservoir characteristics and seepage law of densification reservoir.Based on the high-pressure mercury injection experimental data,the characteristics of S tight reservoir are studied;the micro-pore structure and pore throat structure characteristics of the tight reservoir are studied.The fractal characteristics of the pore structure of the tight reservoir in block S are studied.The fractal dimension range and the average value of the mercury injection curve of rock samples are calculated by using three model formulas,and the applicability of the model is evaluated.The fractal dimension of mercury injection curve is between 2.471-4.625,with an average of 3.13;The fractal dimension distribution range of mercury withdrawal curve is 2.034-2.985,with an average of2.305,which reflects the heterogeneity of the pore throat structure of the tight reservoir in S block.The capillary force curve is used to calculate the relative permeability curve and normalize it to study the oil-water two-phase flow mechanism of the tight reservoir in block S.The influence factors of the relative permeability curve are analyzed.The difference between reservoir rock wettability and pore structure results in different oilwater relative permeability curves and water flooding results.The relevant data and analysis results obtained in this study provide some theoretical guidance for reservoir engineering and efficient development of tight reservoirs in block S.