摘要
Highly precise acoustic impedance inversion is a key technology for pre-drilling prediction by VSP data. In this paper, based on the facts that VSP data has high resolution, high signal to noise ratio, and the downgoing and upgoing waves can be accurately separated, we propose a method of predicting the impedance below the borehole in front of the bit using VSP data. First, the method of nonlinear iterative inversion is adopted to invert for impedance using the VSP corridor stack. Then, by modifying the damping factor in the iteration and using the preconditioned conjugate gradient method to solve the equations, the stability and convergence of the inversion results can be enhanced. The results of theoretical models and actual data demonstrate that the method is effective for pre-drilling prediction using VSP data.
高度精确的声学的阻抗倒置是为预先钻的一种关键技术由 VSP 数据的预言。在这篇论文，基于 VSP 数据有高分辨率的事实，高发信号到噪音比率，并且下面去并且在去上面，波浪能精确地被分开，我们建议用 VSP 数据在位前面在地上凿穿下面预言阻抗的一个方法。首先，非线性的反复的倒置的方法被采用用 VSP 走廊栈为阻抗转换。然后，由在重复并且用 preconditioned 修改抑制因素结合坡度方法解决倒置结果的方程，稳定性和集中能被提高。理论模型和实际数据的结果证明方法为预先钻是有效的预言使用 VSP 数据。
