Study On The Method Of Time-shift Polarization Analysis In VSP Three-component Detection

For three components seismic detection,each single component record is just a projection of three-dimension vector wave-field.With the wave-field's essence is three-dimension and vector,the polarization analysis of wave-field is purpose to extract characteristic of space polarization,and to get vector wave-filed from the record of single component detector.There are some significant and special usages which focus on VSP:Fist,geophone horizontal location of VSP needs polarization analysis.Then,facing on complex wave-field of VSP,polarization analysis could make great help in wave-field recognition and separation.The thesis content is mainly as follows:the characteristic analysis of VSP polarization, including the basic theory of polarization analysis and wave-field synthesis of three components VSP seismic,and emphatically introduce some time-shift methods,including Estimation of polarization in mixed wave-fields by Cho and Spencer,Covariance matrix analytical method and Time-shift energy criterion analytical method based on FK filter.With the programming tools,we produce VSP geophone horizontal location processing module,and accomplish time-shift synthesis of three-component seismic processing module with three methods mentioned above.The theoretical data and practical data is applied to test processing module with satisfactory results.The difference of results between different methods have been analyzed,and the practicality and superiority-inferiority of different methods are demonstrated.The testify result of theoretical data and practical data show that:â‘ Traditional time-invariance VSP three-component synthesize method,as energy criterion analytical method,could get good results in geophone horizontal location.But in polarization aspect,there are more errors.â‘¡The method of estimation of polarization in mixed wave-fields by Cho and Spencer which is belongs to spectral matrix analysis method.The satisfactory result for theoretical data and practical data demonstrate the correctness and efficiency of this method.â‘¢Covariance matrix analytical method is proper in dealing with theoretical data,but for practical data,the process result will be more unreliable.Cause the complex wave-field will make the polarization angle computed by this method inaccuracy.And the range of time-windows have great impact on the computing result.â‘£Time-shift energy criterion analytical method based on FK filter use human-computer interaction system which make the process more flexible,but the subjective factor will make influence on the result.