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将交错网格高阶有限差分纵横波分离的方法与逆时偏移成像方法相结合,给出了基于裂缝诱导TTI双孔隙介质模型的纵波逆时偏移成像算法,并对二维水平层状模型的数据进行偏移成像.结果表明,对于裂缝诱导TTI双孔隙介质模型,常规的基于各向同性背景孔隙岩石速度的偏移方法会导致成像结果出现过偏移现象.为研究裂缝参数对过偏移程度的影响,利用Christoffel方程,对裂缝诱导TTI双孔隙介质模型中的相速度公式进行了推导,并在此基础上,分析了裂缝角度和密度参数对介质纵波相速度及成像位置的影响.结果表明,在二维情况下,裂缝极化角增大会减小成像速度与真实速度之间的误差,从而使得成像结果逐渐接近储层的真实位置;而裂缝密度的增大则使得速度误差增大,导致成像结果与真实模型的偏差越来越大.
Combining the method of high-order finite-difference longitudinal and transverse wave separation of staggered-grid with the inverse time migration imaging method, a longitudinal wave inverse time migration imaging algorithm based on the crack induced TTI dual-porosity medium model is presented. The two-dimensional horizontal layered The results show that for the fracture-induced TTI dual-porosity media model, the conventional migration method based on the isotropic background pore rock velocity leads to the over-migration of imaging results.In order to study the influence of fracture parameters on The influence of the degree of displacement on the phase velocity in the crack-induced TTI double-porosity medium model was deduced by using the Christoffel equation. On the basis of this, the influence of the crack angle and density parameters on the P- The results show that in the two - dimensional case, the increase of the crack polarization angle will reduce the error between the imaging speed and the real speed, so that the imaging result will gradually approach the true position of the reservoir. The increase of crack density will make the speed error Increase, resulting in the deviation of the imaging results from the real model more and more.