P-wave Coupling To Cased Hole In Biot Solid

With the rapid development of modem industry,more and more demand for resources,this reality requires us to explore more effective exploration and development of resources means.Formation of sonic exploration of oil and gas in storage,and other resources,mineral exploration is currently used in a wide range of effective means of.Acoustic logging is in the field of geophysical and rapid development of a wide range of logging methods,acoustic logging on the recent formation of the detailed description of wells is not a substitute for other methods of logging.From the 1950s,the acoustic logging technology is developing rapidly,in the development of oil and gas resources play an important role,but far from well on the acoustic logging formation of the very limited ability to detect,radial detection shallow depth,it is obviously insufficient.Well make up for this earthquake is lcss than one of the ways.At home and abroad show a large number of test data between wells in the earthquake reveal subtle characteristics of the reservoir advantage.Sonic and the coupling of borehole wells seismic study is one of the ways,[13]on the plane P wave and open hole of the coupling carried out a detailed study,with the actual production of the basic involved are well casing,Demands that we must study well casing of the sound field,the paper is in this premise of the research.This paper briefly introduce the history of the acoustic logging and development, introduced the public that is being described porous medium wave propagation of the best theoretical model - Biot theory,and according to actual production,the establishment of the corresponding casing wells Physical model.According to general principles of Fourier series,the incident plane started for the P-wave band-bessel function of the stack,application-wide frequency of Biot theory,detailed derivation of the expression of wells inside and outside sound field.Finally,Matlab software was simulated.This paper on the P-wave vertical plane incident when the sound field casing wells and open hole and the circumstances were compared,the study showed that the plane was well P-wave radio will cause cylinder radial resonance,is fluid radial resonance.So resonance frequency radius of major decisions by the fluid,fluid radius increase to the low-frequency resonance frequency shifts in the fluid radius of the same circumstances(the same resonance frequency),the well casing resonance peak is better than open hole of the high peaks.The open hole-resonance frequency increases with the gradual decrease of the well casing,because there are three interface,occurred repeatedly Catadioptric,Formant changes are complex,laws were not evident.Especially with the soft strata,in the open holc wells in the first resonance peak in the radius of the same fluid casing wells disappear.When the plane P wave and the well shaft angle is gradually increasing,the hard formation,when the angle of less than 60 degrees,with the change in incidence angleα,Formant very dramatic changes in the abbreviated radio(3 degrees)And 45 degrees,will be more of a strong resonance peak in theαangle greater than 60 degrees,with the increase of resonance peak incidence angle changes very stable on the soft strata,when less than 70-degree angleα.With the angle of change,change is very dramatic resonance peak in about 23 degrees and 61 degrees,will be more of a strong resonance peak in theαangle greater than 70 degrees,with the increasing incidence angle Formant big changes are smooth;whether soft or hard formtion formation,with the increasing incidence angle,the resonance frequency to the low-frequency mobile,soft stratum than the rate of the mobile hard formation.When logging equipment are generally placed in the wells,under normal circumstances require wells in the shaft,but due to various errors,apparatus is not well in the shaft,and with advances in technology,machines can be placed on the wall,We need to study deviated from the well-axis measuring the impact of research results show that:the hard formation,when measured less than 2KHz frequency, different position on the wall of sound pressure is basically the same,when more often than 2KHz,the different position of the wall Sound pressure differences more obvious,so different from the position of sound pressure differences must be considered on the soft strata,when measuring frequency below 3KHz,the different position of the wall of sound pressure is basically the same,when the frequency higher than 3KHz,different wall Position of the sound pressure differences more obvious,so different from the position of sound pressure differences must be considered.As porosity and permeability of the oil and gas resources in the development of important significance,the paper mainly inspected the porosity and permeability of the impact of sound pressure wells.Porosity of the inspection results show that:both hard and soft strata,with the porosity of the increase,the resonant frequency to the high-frequency mobile,the smaller the angleα,the resonant frequency to the high-frequency mobile more obvious.Angleαis,the higher the frequency,with the porosity of the changes in resonance peak rate of more drastic changes,the same angle,the soft strata than hard formation rate of change greater resonance.Whether hard or soft strata formation,taking into account the porosity changes arising from the porosity and bending of the changes,as the penetration rote increases, the resonance frequency to the high-frequency mobile,the greater the angleα,the penetration rate of Formant The impact of the smaller,the smaller the angleα,the greater resonance peak amplitude changes.The low-frequency,only a very angleα, the penetration rate was significantly affected.All in all,well casing circumstances porosity of the resonance peak penetration rate than the impact of the high-impact. Both soft and hard formation peak is the highest peak in the resonance angle of 45 degreesα.The results of this paper to explain the seismic section of the vertical wells and seismic survey data with a certain sense,while cementing quality testing,repair old wells to provide a theoretical basis.The next step is to start plane SV wave couplcd with the well casing of the theoretical research and numerical simulation.