Propagation characteristics of joint physical simulation of both electromagnetic wave and ultrasonic wave in fractured media model

Abstract

Fractured reservoir plays an important role in exploitation of the oil-gas recourses especially shale gas, at the same time the fractures have an important influence on the dams, bridges, highways and other builds. So fracture detection and its attribute evaluation is an important aim on study of exploration geophysics. Both electromagnetic wave and elastic wave have a good effect on fracture detection and its attribute evaluation. Joint exploration and inversion is an effective way to improve the accuracy of exploration. But we needs further study on the propagation response characteristics of electromagnetic wave and elastic wave. Physical simulation is an intuitionistic and effective method in study two kinds of wave-field propagation response characteristics in fractured media. So we carry out the combining electromagnetic wave and ultrasonic wave physical simulation experiment on fractured medium model. We have established a three-dimensional physical model with a series of tiny parallel fractures in the vertical. And we have explored this model using by ground penetrating radar, and collected electromagnetic sounding data of three-dimensional co-polarization and cross-polarization, and analysed polarization characteristics. At the same time we have explored this model using three-component transducer, and collected elastic wave data of three-dimensional, and analysed shear wave propagation characteristics. By making a study of the change of co-polarization and cross-polarization response amplitude values and the phenomenon of S-wave splitting in elastic wave, we can judge the direction and density of cracks and other properties in it. By study of the two kinds of wave-field physical simulation, we can lay a solid foundation for joint inversion of electromagnetic wave and ultrasonic wave in the future.