约束等效源稳定向下延拓方法研究

在等效源向下延拓方法的理论基础上，研究提出加入观测平面以下空间实测数据作为约束的等效源约束向下延拓法，用于二维位场数据向下延拓.与传统的向下延拓方法和等效源法延拓相比，等效源约束向下延拓法抗噪声性强，能延拓出由于延拓深度过大而衰减至难以探测的高频信号，使延拓结果更接近真实值.理论重力模型数据的延拓结果显示该方法有效，延拓结果优于传统波数域迭代法和等效源法.利用等效源约束延拓法对我国某海域水面实测重力值进行向下延拓并与水下实测值进行对比，结果表明该方法延拓结果最接近实测值.本文方法为我国深水油气近海底重磁高精度探测研究提供一定的技术支撑.

Stable downward continuation of potential field data using an equivalent source method and a constrained strategy

Based on the principles of equivalent source method, the presented work proposes a constrained equivalent source for downward continuation of potential filed data, of which the constraint includes the data measured below the observation surface. The equivalent source constrained downward continuation method exhibits improved noise suppression and can capture high-frequency signals that are difficult to probe due to the increasing continuation depth, thus providing more realistic results compared with the conventional downward continuation method. The results of the continuation of synthetic gravity data demonstrate that this method is more accurate than traditional wave number domain iteration method and equivalent source method, evidencing its effectiveness. The downward continuation of the gravity data measured on the surface of a certain sea area in China agrees very well with the data measured underwater. The equivalent source constrained downward continuation method provides technical support for the research of high precision gravity and magnetic exploration of deep-water oil and gas near seabed in China.