TIME-FREQUENCY ELECTROMAGNETIC DATA CORRECTION PROCESSING AND RESERVOIR EVALUATION BASED ON DISPERSION TEST ANALYSIS

Time-frequency electromagnetic method(TFEM), as a relatively mature oil and gas detection technology, has been widely used both in China and overseas. In the process of time-frequency electromagnetic interpretation, the combined qualitative detection of resistivity and polarizability is commonly used. However, such method cannot quantitatively evaluate the oil and gas content, and regards the formation resistivity as a quantity independent of temperature and pressure. In fact, with the increase of formation depth, the temperature and pressure changes of the formation will affect the resistivity, which would cause errors to reservoir interpretation. This paper analyzes the variation law of rock electrical parameters with frequency through the frequency dispersion test of rock. Combined with the dispersion properties of rock, the variation characteristics of formation resistivity affected by temperature and pressure are studied, and then the approximate relationship between rock resistivity and temperature/pressure is obtained by fitting. Using appropriate temperature-pressure-resistivity function, the time-frequency electromagnetic reservoir data are corrected for resistivity, by which the saturation of the target reservoir in the study area is calculated with the Archie formula, and the reservoir is quantitatively evaluated.