| The permeability and resistivity of rock play an important role in comprehensive evaluation and development of reservoirs(productivity evaluation and well logging interpretation),while the tight reservoir of Xujiahe formation has micro-nano pore throat development,complex pore morphology and strong heterogeneity,which makes it difficult to accurately evaluate the permeability and electrical conductivity parameters,it has been very difficult to obtain permeability parameters through resistivity logging.In this paper aims at the tight sandstone reservoir of Xujiahe formation in central Sichuan,carried out microscopic experiments,permeability and electrical experiments,and based on theoretical model and experimental fitting method to establish the relationship between permeability and electrical properties,and the influencing factors of related parameters were analyzed by combining the microscopic pore structure.The main research work of the thesis and related knowledge are as follows:(1)Based on the tine sections,scanning electron microscopy,X-ray diffraction whole rock mineral analysis technology,capillary pressure curve,the microscopic pore structure and mineral composition of the tight reservoir in Xujiahe formation were analyzed,and the parameters such as pore types,pore sizes,cement type and mineral composition were obtained.(2)The experiments of basic physical properties(permeability and porosity)of the tight reservoir rock samples(30 pieces)of Xujiahe formation were completed,and the relationship between the porosity and permeability of the reservoir was fitted to study its pore-permeability physical properties and heterogeneity.(3)The rock-electricity experiments of the tight reservoir rock samples(12 pieces)of Xujiahe formation were conducted by the gas flooding method,and the relationship between the formation factor F and porosity ?,the resistance increasing coefficient RI and the water saturation Sw ware established under double logarithmic coordinates,and four key parameters(m,n,a,b)were obtained.Then combined with microscopic pore structure characteristics to study the non-Archie linearity under low and high water saturation and the variation of petroelectric parameters.(4)The gas-water phase infiltration curves of the tight reservoir rock samples(12 pieces)of Xujiahe formation were obtained by the gas-water phase infiltration experiment.And the reservoirs of the Xujiahe formation were classified with the characteristics of the curves.The changes in relationships between physical properties(porosity and permeability)and the characteristic parameters such as Swi?Sgr?SX?krw(Sgr)?krg(Swi)and krx(Sx)of the phase infiltration curve was studied.The effects of clay minerals,quartz,feldspar content and pore structure on permeability parameters were also analyzed.(5)Using nuclear magnetic resonance technology to analyze the NMR T2 spectra of before and after the displacement of the rock power experiment for the tight reservoir rock samples(12 pieces)of Xujiahe formation.And the distribution characteristics of the reservoir fluid was also studied,which included the calculation of the lower limit of the flow radius,the characteristics of the bound water and the distribution of the movable fluid.(6)The relationship between permeability and electrical properties of Xujiahe formation tight sandstone reservoirs was established,and the influencing factors of related parameters were comprehensively analyzed by combining the microscopic pore structure parameters.The development of this study has theoretical and practical value for understanding the microscopic pore structure?clear the influence of pore structure parameters on permeability and electrical parameters and revealing the intrinsic relationship between permeability and electrical characteristics of the tight sandstone reservoirs of the Xujiahe formation in central Sichuan,which also laid a foundation for comprehensive evaluation and development of the tight reservoir. |
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