论文详情
针对我国南方山地探区复杂地表和复杂地下构造导致常规各向同性叠前深度偏移难以准确成像问题,研究了基于TTI各向异性的全速度建模技术,建立了一套起伏地表条件下各向异性全速度建模的技术思路和实现流程。首先采用井约束初至层析反演方法建立准确的起伏地表速度模型,将其与常规处理获得的中深层速度模型进行匹配拼接,建立起初始的各向同性起伏地表全速度模型;然后通过井震联合的方法获取各向异性参数,将其加入到各向同性起伏地表全速度模型中,结合倾角和方位角数据,实现TTI各向异性起伏地表全速度建模。四川盆地DXC工区地震资料的成像处理验证了各向异性全速度建模技术的有效性;基于TTI各向异性全速度模型的起伏地表Kirchhoff叠前深度偏移结果有效地消除了起伏地表的影响,同时降低了复杂构造与速度各向异性对地震成像的影响,使得地下构造成像更合理也更精确。
The complex surface and the complex underground structure lead to inaccurate image from the conventional isotropic pre-stack depth migration in the mountainous area of southern China.Aiming at the problem,a full velocity modeling technology based on TTI anisotropy was studied,a series of technical ideas and workflow of anisotropy full velocity modeling from rugged topography was established.Firstly an accurate irregular surface velocity model was built by the well-constrained first arrival tomographic inversion method.Secondly,an initial irregular surface isotropic full velocity model was built by matching and stitching the near surface model and the mid-depth velocity model was obtained by conventional data processing.Then the anisotropy parameters was obtained through borehole-seismic joint method.Finally,the TTI anisotropic irregular surface full velocity modeling was accomplished by integrating the dip,azimuth and anisotropy parameters into the existing initial irregular surface isotropic full velocity model.Apply the velocity modeling technology to the seismic image of DXC survey in the Sichuan Basin.The processing results show that anisotropic full velocity modeling can achieve available full velocity modeling in the mountainous area; TTI anisotropy velocity model based Kirchhoff pre-stack depth migration from rugged surface can eliminate the influenc of rugged topography and reduce the impact of complex structure and velocity anisotropy on the seismic imaging.
国家自然科学基金项目(41304115,41204101)资助。