非线性层析反演速度建模技术

Non-linear Tomography Inversion Technology for Velocity Modeling

深度速度模型的构建仍然是地震成像中的巨大挑战,获得一个精确的深度速度模型和减少深度成像项目周期都是至关重要的。常规层析反演速度建模每次迭代相当于一次线性反演,且需要重新的拾取工作,导致非常耗时,效率低下。本文提出非线性层析反演速度建模技术来建立速度模型。拾取共成像点道集的RMO量,转换到叠前域,作为运动学不变量,通过层析反演迭代进行模型更新。用一个多次的线性反演来逼近一个非线性的物理过程,避免重复的拾取工作,大大提高项目的运转效率。通过实例证明该方法的有效性。

The estimation of depth velocity model is a great challenge in seismic imaging, obtaining an accurate depth velocity model and reducing the depth of imaging project turnaround time are of critical importance. The velocity modeling of conventional tomographic inversion is equivalent to a linear inversion, and need to be re-picked up, which leads to very time consuming and low efficiency. A velocity modeling method based on nonlinear tomography is proposed. The RMO of the common imaging point gathers is converted to the pre stack domain as the kinematic invariant, and the model updating is carried out by the iteration of the tomographic inversion. A multiple linear inversion is used to approximate a nonlinear physical process, which avoids the repetitive work and greatly improves the efficiency of project. The validity of method is proved by an example.