Petrophysical Experiment For Carbonate Rock Of Changxing And Feixianguan Formation In Sichuan Basin

The carbonate reservoirs of Feixianguan Formation and Changxing Formation in Longgang area,Sichuan basin present complex pore structure and logging response characteristics,strong heterogeneity and multi-solution of logging interpretation,which makes it difficult to reservoir fluid identification and accurate calculation of parameters.According to the carbonate reservoir evaluation requirements of target area,this paper systematically studies lithology,physical,electrical,and acoustic characteristics of reservoirs with rock physical experiment.This paper analyses pore structure microscopic characteristics of carbonate reservoirs,so as to provide help for well logging macroscopic response characteristics and experimental basis for the calculation of reservoir parameters.According to observation of core and rock slice,reservoir space was composed of intergranular dissolved pore,intragranular dissolved pore,intercrystalline pore,intercrystalline dissolved pore and fracture.the lithology is major in dolomite,the distribution scale of porosity and permeability is large and its characteristics is complex.The analysis of porosity and permeability experiment data shows that Formation pressure has little effect on porosity and permeability.Based on mercury penetration and NMR experiment,the pore texture of reservoir is divided into four types from the point of pore scale,throat distribution and Pore types.The different classification criterion for pore texture is identified.Based on the above,combining T2 cotoff value and different layers,the pore texture of reservoir could be divided into seven types.Combining rock electrical properties experiment and pore texture,the non-Archie phenomenon of rock-electricity relation was effected by primary pore and dissolution pore.The compressional and shear waves experiments which are under different pore fluid conditions show that the acoustic characteristics of rock samples changes significantly in fluid properties,especially the increasing of gas saturation makes rock samples compressional wave velocity reduce significantly,so that the ratio of the compressional wave velocity to shear wave velocity reduced significantly.Therefore,commenting the containing gas quality by using compressional and shear waves and elastic parameters of the evaluation of reservoir rock may have a good application effect.