Interface Waves At Plane And Cylindrical Fluid-solid Interface

Acoustic logging technology is widely applied in the field of oil and gas resourceexploration. Acoustic logging technology has made great progress in the past40years,which is promoted by the development of borehole acoustic field theory. At present, asthe oil and gas exploration work in China facing the exploration problem of complexand unconventional stratum, the types of the reservoir parameter which should bemeasured have increased, and the properties of near-borehole stratum needs furtherunderstanding, so further researches on acoustic logging should be done. Research anddevelop of new logging instrument need more thorough understanding of the acousticfield in borehole. In this thesis, the well of the borehole is regarded as the fluid-solidcylindrical layered interface, and then study the two kinds of surface wave propagatedalong the interface with fluid on the one side and solid on the other side, which arePseudo-Rayleigh Wave and Stoneley Wave. And analyze the connections between themand the Scholte Wave that propagated along the plane surface in the high frequencylimit.Firstly, deriving the character formula of Scholte Wave based on the case of fluid-solid plane interface. Point out that the Scholte Waves propagating along the planeinterface do not disperse. Then deriving the analytical solutions of Scholte Wave indifferent stratal situations. And calculate the Scholte Waves’ velocity in differentsituations by using the analytical solutions. Then discuss the relationship between thevelocity of Scholte Wave and the stratum parameter.Secondly, research the sound field under the situation of cylindrical interface usingclassical borehole model. Then calculate the frequency dispersion curves, excitationintensity curves, the full wave time domain waveform. Especially discuss the cut-offfrequency of Pseudo-Rayleigh Wave.Further more, contrast the Pseudo-Rayleigh Wave and Stoneley Wave with ScholteWave in the high frequency limit. And illustrate that these three kind of surface wavestend to coincide in the high frequency limit.Finally, separately deriving displacement equations of Rayleigh Wave andPseudo-Rayleigh Wave. Use numerical methods to calculate the particle trajectory ofboth kinds of waves and research their relationship in the high frequency limit. Thencontract the particle trajectory of Pseudo-Rayleigh Wave in different depth to study the attenuation law and put forward to evaluate the detection depth standard.