Physical Property Measured And Spectrum Parameter Analysis Under Formation Condition

As an important storage medium for oil and gas resources,rock is a natural aggregate composed of one or more minerals combined in a certain way.The properties of rocks are related to the composition of their constituent minerals and the volumetric content of minerals,and the geometric distribution and cementation of constituent minerals in rocks.The size of the mineral particles,the presence of pore fluids,the temperature and pressure all affect the physical properties of the rock.As an important means of oil and gas resources exploration,petrophysical technology can not only provide necessary data for exploration inversion,but also greatly reduce the multi-solution of inversion.The traditional study of rock electrical properties is mainly concentrated under normal temperature and pressure conditions,but the actual reservoirs are in high temperature and high pressure environment.The evaluation of oil and gas reservoirs under high temperature and high pressure by experiments at normal temperature and pressure is usually not accurate enough and may even lead to erroneous interpretation results.Therefore,studying the electrical properties of rocks under formation conditions has important theoretical significance and practical application value.In this paper,the complex thermal resistivity of shale,dolomite and artificial sandstone containing conductive minerals was measured by the AutoLab-1000 high temperature and high pressure experimental platform and SI-1260 impedance tensor analyzer.Based on the Debye decomposition model and the double Cole-Cole model,the spectral parameters of artificial sandstone and shale are obtained.The research shows that the resistivity of rock is greatly affected by the connectivity of metal particles and the pressure of formation.For rock samples with metal minerals and good mineral connectivity,the resistivity decreases with the increase of formation pressure.Otherwise,the higher the formation pressure,the higher the resistivity;for artificial standards with less conductive mineral content and poor connectivity,the time constant increases with the increase of formation pressure.It is found that the formation pressure has a higher influence of polarizability for sandstones containing metal minerals.under the influence of formation pressure,the level of conductive minerals will no longer uniquely determine the main polarization of the rock(ion polarization,electron polarization).By changing the solubility of the pore fluid and the ion activation energy,the temperature not only reduces the rock resistivity,but also increases the rock polarizability.the rock phase amplitude has a completely opposite trend with the pressure change in the high and low frequency bands.