Induced Polarization Characteristics Of Reservoir Rocks With Different Wettability

The physical response of reservoir rocks is complex,and reservoir wettability is one of the problems that have been paid attention to and studied for a long time in reservoir development.The induced polarization characteristics of reservoir rocks can play a key role in reservoir evaluation during oil and gas exploration and development.The intensity of induced polarization phenomenon is related to the physical properties of rocks,the properties of solutions contained in them and the distribution of solutions in pores,that is,the wettability of reservoir rocks will affect its induced polarization characteristics,and the wettability of reservoir rocks can be studied through the induced polarization characteristics.However,the mechanism research on induced polarization characteristics of reservoir rocks with different wettability is still not deep enough.In this paper,the selected reservoir rocks spread from high porosity and permeability reservoir rocks to low porosity and permeability reservoir rocks.Based on the information of rock sample composition,porosity and permeability obtained by comprehensive test,combined with measuring instruments,the wetting angle and wetting index of rocks in clean and aging States and the complex resistivity of rocks under different oil saturation are measured.In this paper,the theoretical basis of rock wettability and induced polarization mechanism characteristics is summarized.The complex resistivity testing method and technology of reservoir rocks with different wettability under oil content are studied,and the experimental results of wettability and complex resistivity testing of reservoir rocks are obtained.Through Debye model,Cole-Cole model,Generalized Cole-Col model,Multi-Cole-Cole model,Dias model and MGEMTIP model,the low-frequency data of complex resistivity data test results are inverted.From model derivation to practice,MGEMTIP model is finally selected for data processing through comparative fitting,and IP parameters are obtained by inversion.The relationship between IP parameters and oil saturation of dense rock samples and high porosity and permeability rock samples before and after aging is analyzed respectively.Combined with the wettability measurement results and IP parameters,GCS model and MVN model,the influence mechanism of wettability on IP characteristics is analyzed and revealed,and the induced polarization response characteristics of reservoirs with different wettability are studied,which provides physical basis for oil and gas reservoir exploration and development and reservoir evaluation.