Study On Permeability Evaluation Method Of Carbonate Reservoir Based On Electrical Imaging Logging

At present,large-scale and high-yield oil and gas fields in the world are mostly come from carbonate reservoirs.The reserves of carbonate rocks in the Middle East account for 70% of the world's total reserves.Carbonate reservoirs are characterized by complex lithology,diverse pore types,strong heterogeneity and complex logging response,which make it difficult to quantitatively evaluate logging parameters.The electrical imaging logging data has the characteristics of high resolution and intuition.It can identify the formation structure,size and shape of pore These advantages of electrical imaging logging provide an important basis for quantitative evaluation of carbonate logging interpretation.Taking the carbonate reservoir of an oilfield in the Middle East as an example,this paper understands the geological survey of the study area and analyzes the influencing factors of formation permeability from the aspects of lithology,physical properties and reservoir space characteristics.In addition,taking the ERMI data of micro resistivity scanning logging tool as the research object,the structure,measuring principle and influencing factors of the instrument are studied,and then the data measured by the instrument are pre-processed,corrected,generated and displayed.On the basis of the above research,the exponential relationship between rock plane porosity and permeability is deduced according to the double effective medium approximation theory,and the plane porosity of thin section is accurately extracted to verify the permeability model.For the whole well evaluation,morphological operator and OTSU algorithm are used to filter,segment and extract the image of the electrical imaging logging image.Finally,the reservoir permeability is estimated by the established model,and the continuous evaluation of the whole well of the carbonate reservoir permeability by the electrical imaging logging is realized.Compared with the conventional model,this method can improve the calculation accuracy and reflect the heterogeneity of reservoir,which provides a new effective method for the permeability evaluation of complex carbonate reservoir.For the pore-porous carbonate reservoir with a small amount of shale,the classical Archie formula,the conductivity efficiency formula and the Simandoux formula are used to invert the porosity spectrum.The porosity spectrum is compared and analyzed,and the secondary porosity of reservoirs is calculated.By analyzing the applicability of several methods in this study area,the Simandoux formula with shale correction is selected to invert the porosity spectrum,and the secondary porosity model is used to predict reservoir permeability.Comparing with core permeability,this method has high accuracy and good application effect.