| Formation resistivity is an important parameter for oil and gas interpretation andevaluation in the well logging. With the deepening of fine oil and gas exploration, electricalanisotropy reservoir such as the conglomerate formation, thin layer interactions, denseformation, porosity and fissured formation becomes important development direction. Theconventional measuring technique and interpretation theory is no longer applicable. It is urgentto strengthen the electric anisotropic electromagnetic theory research, and put forward a newmeasurement technology，establish the quantitative relationship between the anisotropic tensorresistivity (the reciprocal of tensor conductivity) and the formation of oil and gas evaluationparameters, to provide theoretical basis for oil and gas interpertation and evaluation. Thisthesis takes conglomerate formation as the research object, uses the finite element numericalcalculation sotfware COMSOL to research the quantitative relationship between electricconductivity and rock "four properties’1, and the response mechanism of induction logging inconglomerate formation, and also study the electric logging numerical calculation methodwhich is based on the COMSOL sotfware, and applied it to the calculation analysis of arrayinduction logging problem. Main research contents and results are showed in the followingfive aspects.The first part is the study of electric logging forward calculation method. Designspherical logging model which has a certain populairzation and the grid subdivision for thismodel, greatly improve the computational eiffciency and computational accuracy. Solve theproblems of external boundary, whether to add infinite element and source equivalent. Itmakes the practical engineering numerical calculation possible.The second part studies the charge distirbution of nonuniform conductive mediumfeatures in constant current field. Use the mirror principle to deduce surface charge density oftwo layers of infinite conductive medium and interface of medium and air. Use COMSOLsotfware to compute surface charge density in two ifnite conductive media. In finite medium,the numerical calculation reveals quantitatively the charge distirbution features in corner, edgeand intersecting line on the surface.The third part studies the quantitative relationship between the conglomerate formation conductivity and the rock "four properties". Design anisotropic conglomerate model，researchquantitatively the relationship of tensor conductivity in conglomerate formation withformation factor and pore lfuid. We find that formation factor is anisotropic, while the porefluid in the formation is not anisotropic.The fourth part studies array induction logging response of the conglomerate formationand its mechanism. Establish a single conglomerate model to calculate the response of singleconglomerate to the array induction tool with changes of the space position and backgroundconductivity. By numerical calculation the space trajectory of eddy current around theborehole in conglomerate formation is obtained. It reveals the array induction loggingresponse mechanism in the conglomerate reservoir.The fitfh part studies other numerical calculation problems of array induction. First ofall, solve the problem of response calculation of array induction logging in eccentric situation.The eccentric database is established, which has been applied in actual engineering. Secondlydesign the calculation model of the spheircal area peirphery and mapping inifnite element. Ithas solved problems of the metal impact calculation when the calibrating array induction tool.Finally, based on the geometric factor, a numerical calculation sotfware is developed tocalculate response in the conglomerate formation. |
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