| Because of the method of seismic exploration's high precision, high resolution and depth detection, it is as the most important geophysical technology has widely used in the exploration and development of oil fields, gas fields and coal fields all the time. The reflection wave seismic exploration technology as the main technology of seismic exploration process, has make a great success on the oil, gas, coal and other energy minerals exploration. The reflection wave seismic exploration has formed a series of technologies including data acquisition, processing and interpretation. Compared with the oil and other exploration, the geological condition about metal mines exploration and the geological problem would be solve become more complex. Not only the theory, but also the technology method about reflection wave seismic exploration technology can not be directly applied to the metal mines exploration. So, that's need for using wave scatter theory to solve the problem.In the metal mines exploration areas, fill with faults, attitude of geologic body is very complex, lithology change very great, steep dip, there are many little size geologic structure body , ore vein. The special seismic geological condition about metal mine exploration make the metal mine exploration problem fell into the field of seismic scatter wave. To fundamentally solve the problem, should adopt seismic technology based on the seismic wave scatter theory, that is , scatter wave seismic technology which also is the direction of development with metal mine seismic exploration technology in the filed of theory and apply.Scatter wave method mainly used to solve such as the non-uniform medium, complex structure, oil exploration geological exploration problem, especially the complex geological problem which can not be solve well with reflection wave method. On the surface where can not receive the reflection wave from complex part and conventional reflection wave seismic exploration method can not imaging accurately, but on the surface can receive scatter wave from these complex part.Therefore, it is necessary to carry out scatter wave seismic method theory and technology research in order to more effectively resolve metal mine exploration problem. With the deepening of the level of research, seismic method is expected to become an effective way in the metal mine exploration, and play a more important role.Equivalent offset migration method is a pre-stack time migration method which is based on the principle of Kirchhoff time migration, and it can be applied to both 2-D and 3-D data. At same time, the equivalent offset migration method also applicable to P-SV wave data processing. Equivalent offset migration method is based on scatter theory, the double square root equation of seismic wave travel time cleverly converted into a single square root equation without time shifting. It use pre-stack Kirchhoff integral migration theory, the seismic gathers according to the scatter point, by equivalent offset in a given range of migration aperture mapped into common scatter point gathers. In the common scatter point gathers, the scatter energy is distributed according to hyperbolic, CSP gathers express the location of surface point. The key step of this method is formation of common scatter point gathers. Equivalent offset is defined as the surface distance from the scatter point to a collocated source and receiver. The concept of equivalent offset provided a new idea to seismic pres-tack migration and velocity estimation. Equivalent offset migration method gains computation efficiency by delying the Kirchhoff computations until after the CSP gathers has been formed, it's computation efficiency higher than pre-stack Kirchhoff migration method.In addition, with the level of oil exploration and degree of exploration increased, the conventional P wave seismic exploration technology faces many challenge. To resolve these complex issues, on the seismic exploration technology, only relying a conventional three dimensional seismic of single wave style can not be solved, must be adopt synthetical geophysical technique. Because multi-wave multi-component seismic exploration data contain more extensive seismic wave field, analysis P-SV wave data and P wave data, processing and interpretation, compensate for the lack of P wave exploration to improve the accuracy of exploration. Among them, the convert wave exploration cost less, gain more information, has become research hot area of seismic exploration field. Convert wave exploration can also provide speed information of multi-wave, realize real exploration of lithology exploration. But, due to the asymmetric of convert wave travel trace, the speed of incident wave is different from the speed of reflective wave, so the imaging of convert wave data more complex than the longitudinal wave data. Multi-wave exploration has been more and more geophysical academic attention. Multi-wave multi-component seismic exploration technology is one of the most promising scientific exploration and seismology leading edge subject.The equivalent offset migration method for convert wave data, the input samples are mapped to a common convert scatter point (CCSP) gathers, this method is simple and fast. In CCSP gathers, the relationship between the two-way travel time and equivalent offset is proven to be hyperbolic making the conventional P-P velocity analysis tool suitable to P-SV velocity analysis. The equivalent offset migration method for convert wave data processing can simplify the conventional P-SV wave data processing. This provides a simple but powerful way to perform convert wave migration velocity analysis and simplify the P-SV processing.This paper according to metal mine seismic exploration technology in the field of theory and application of the direction of development and prospect, contact with urgency of our energy need, as well as scatter theory, the equivalent offset migration of P wave and P-SV wave to achieve high-quality imaging, mainly to complete the following work:(1)By a large number of data access, deeply understand the basic theory of equivalent offset migration (EOM) method, it can be applied to 2-D and 3-D data, it can processing not only P wave data, but also P-SV wave data. Equivalent offset migration method based on Kirchhoff pre-stack time migration, it's computation efficiency faster than Kirchhoff pre-stack time migration, and easy to implement. Equivalent offset migration method has natural anti-aliasing feature, during dealing with irregular sparse data has unique advantage, and for realizing metal mine seismic exploration, small size geological body imaging provide new method and idea.(2)For the equivalent offset migration method, the most crucial step is the formation of common scatter point (CSP) gathers. So I write program for the formation of common scatter point, and summarize the common scatter point gathers feature of typical P wave model, during the formation of common scatter point gathers without time shifting, the scatter energy of gathers distributed according to hyperbola. By contracting with conventional common mid point (CMP) gathers, the common scatter point gathers has greater coverage, make full use of the seismic signal of effective information, velocity analysis based on common scatter point gathers can provide more reasonable velocity parameters for imaging.(3)Equivalent offset migration method is not sensitive to the initial velocity, so this paper done a test of converge of velocity for CSP gathers and the sensitivity of equivalent offset for velocity, thus concluded that: the initial velocity has very little impact for CSP gathers.(4)Through MATLAB platform achieved equivalent offset pre-stack time migration imaging of P wave model, compare with conventional migration imaging method, the computation efficiency of equivalent offset migration is very high, the continuity of phase axis is better, without obvious draw phenomenon, and it can reflect distribution and shape of underground geological structure well. So that improved signal to noise ratio, especially in the area where full with horizontal velocity change, slope structure and small size geological body, this method showing that the unique advantage and achieve high-quality imaging.(5)Dealing with yield data for further validating the advantage of imaging effect of equivalent offset method, realized high-quality imaging.(6)Due to equivalent offset migration method can be applied to the convert wave processing, and it greatly simplify the convert wave data processing steps, so I write programs to achieve the formation of common converted scatter point(CCSP) gathers by equivalent offset migration method, analysis the common converted scatter point gathers feature of typical converted wave model. The common converted scatter point gathers have a greater coverage range, and during P-SV wave data are mapped into the CCSP gathers and get rid of the asymmetry of P-SV wave ray path. The relationship between equivalent offset and two-way travel time is hyperbolic, so that P-SV wave processing has been to simplify.(7)As same as dealing with P wave data, it also should study the influence of velocity for common converted scatter point gathers, through the test of velocity converge for CCSP gathers and the velocity sensitivity for CCSP gathers, we can see that the impact of initial velocity for CCSP gathers is very small.(8)Though MATLAB platform to achieve equivalent offset pre-stack time migration imaging of P-SV wave model, we can see that when processing P-SV wave data by equivalent offset migration method, the computational efficiency is very high, the seismic phase axis of migration imaging result better, without obvious draw phenomenon, improved signal to noise ratio, and well reflected the distribution and shape of underground geological structure. When existence the tilted structure and small size geological body, this method also show the advantage, and can achieve high-quality imaging.
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