Optimization Of Recording Geometry Based On Illumination Analysis

This paper focuses on the optimization of recording geometry which is based on illumination analysis. The principles utilized in this paper include the principle of ray tracing, the principle of dynamics of seismic wave,and the theory of velocity smooth.The main thread of this paper is listed below: based on the theory of illumination, target layer is analyzed. By forward modeling for complex velocity, we do illumination analysis using ray tracing and wave continuation. The result could be used to evaluating the quality of survey and optimization design of complex exploration area.Traditionally, analysis of recording geometry is based on a single physical point or the theory of horizontal stacking. With the popularization and applications of seismic exploration technologies, the work is gradually focused from the plains to the mountain areas, from the simple to the complex geological structure. However, at the present stage of seismic exploration, the traditional design of observing systems is not suit for complex geological structure.Ray tracing is based on the basic principle of Langan. This principle considers ray path as an independent variable. Location of Ray, direction and travel-time are all algebraic forms of Arc-ray. Ray tracing based on Langan can better solve the problem of local extremum with little calculation.Propagation based on wave equation is suitable for the complex medium. One-way wave equation has high calculating efficiency, with no high-frequency approximation, multi-path and caustics and so on. Fourier finite-difference algorithm for downward and upward extension of the wave field can not only ensure the accuracy of the wave field but also the efficient operation. Illumination is used to analyze poor energy area and energy masked areas which have weak image quality because of insufficient energy. In this paper, we do the forward modeling based on ray tracing and wave theory. In view of the geological model and observation systems, we do illumination analysis to each shot, in order to record the energy distribution of each shot. Using the CDP interval of observation as a line element size, we statistics the striking frequency of ray beat and energy distribution of wave-field and express the analysis results in the form of energy distribution. According to energy distribution maps, the distribution parameters of observing system for work area are determined. Therefore, the shot locations and detectors can be optimized directionally. The experimental results show that: illumination analysis based on ray and wave theory could well reflect the interface energy, and the optimization of observing systems could lead a very good illumination and imaging for targeted area.