The Research And Application Of Fracture Detection Methods Based On Shear Wave Splitting

Strata in the cracks are relatively good, fracture not only is the reservoir space ofoil and gas. but also is the transportation channel of oil and gas, that is to say, thedegree of fracture development in the ground and connectivity of fracture decide theenrichment degree of oil and gas, therefore, looking for the relatively stabledfracture that development zone is the key factor of looking for oil and gas explorationactivity success or failure.Fractured medium is a kind of typical azimuth anisotropic medium,compressional wave is not sensitive spreading on the fracture anisotropic medium, butshear wave is quite sensitive spreading on the fracture anisotropic medium. The shearhappens split phenomenon when it is spreading into the crack anisotropic medium, itwill split into two waves those polarizations are orthogonal components, they havedifferent speeds the shear wave that spread along the crack is defined quickly shearwaves S1, he shear wave that spread vertical cracks is defined slow shear waves S2.Shear wave split phenomenon not only can be used to predicting angle of crack, butalso can be used to explorate the development dimension of cracks. Therefore, shearwave split phenomenon can be used research fissure medium conveniently mediumconveniently, and detect fissure reservoir.The research contents of this paper mainly includes that research crackclassification and formation mechanism, crack anisotropic medium theory, shearsplitting analysis technology and so on three parts. In this paper we will brieflyintroduce crack classification and formation mechanism and we study crackanisotropic characteristics from numerical simulation, Further we deduced with therelationship of fracture developing density is and time difference. Papers areintroduced in detail is the focus of Shear wave splitting analysis method. IncludingFracture forecast technology and crack anisotropic correction technique in the twoaspects of content. Fracture forecast technology include those as follows.Energy ratio method.Polarity reversal method.the Least Square Fitting method and Angle spectralscanning method etc four methods Separation fast-wave and slow-wave have twomethods including Triangle transformation method and Alford orthogonal rotationmethod After completing these theory research The author from the study method ofshear division of the principle of technology Emphasis is Alford orthogonal rotationmethod Alford orthogonal was applied in the theoretical model, the application oftechnology in theory model explain those when profile without noise: (highsignal-to-noise ratio), the Angle of shallow and deep that we calculate match with thetheoretical the time delay of shallow and deep that we calculate match with thetheoretical it tests and verifies the feasibility and accuracy of Alford orthogonalrotating method.we can use fracture forecast technology to accurately calculating theoverlying anisotropic medium cases objective stratum of fracture azimuth anddevelopment density.we can use fracture forecast technology to accurately calculatefracture azimuth and development density of the objective overlying anisotropicmedium.we can able to deal with fracture azimuth and development density predictionproblem of multi-layer anisotropic.In actual 3D3C wide azimuth seismic data, fast andslow shear waves of polarization direction, propagation speed (or time delay),spectrum by fracture development with amplitude attributes the azimuth, fracturedevelopment density, a crack in the influence of filled fluid type. Based on the sheardivision of the calculation and analysis of attribute, facilitate testing fracture trend anddevelopment level, distinguish a crack in the fluid type filling etc.Finally, we usedshear split technology applied to shear three-component and three dimensional actualdata in sichuan, it can realize that this method can correction fractured mediumazimuth anisotropic of multilayer fractured, so as to improve the resolution of theconverted wave stacked profile.Alford orthogonal rotating can be applied in the actual material, able toeffectively predict crack Angle and development effectively, shear splitting can usedazimuth anisotropic correction processing, this has the extremely vital significance inimproving multi-component material processing level, improving the feasibility ofcrack prediction reliability and reservoir prediction reliability and further improve thedeep density fractured reservoir exploration and further improve the deep densityfractured reservoir exploration and development benefits has the extremely vitalsignificance .