利用数值积分提高一维模型电偶源电磁测深响应计算精度

讨论了直接利用数值积分提高电偶源电磁测深响应计算精度的方法．具体为对Hankel积分进行直接积分，结合连分式展开方法以提高积分求和的收敛速度．利用该方法对均匀半空间和层状(两层)模型的电磁测深响应进行了模拟，结果表明与常规的快速Hankel滤波方法相比，采用直接数值积分能明显提高电偶源频率测深响应计算精度．从而为获得高精度瞬变测深晚期响应提供算法基础．

UTILIZING DIRECT INTEGRATION TO ENHANCE CALCULATION ACCURACY OF 1D ELECTROMAGNETIC RESPONSE FOR CURRENT DIPOLE SOURCE

The direct integration method to enhance the calculation accuracy of electromagnetic responses for current dipole source over layered earth is discussed. In the method Hankel integration in frequency domain is divided into several partial ones and are evaluated with the method which combines Gauss quadrature rule and continued fraction. The utility of continuous fraction can speed up the convergence greatly. Using the method the electromagnetic responses for half-space and two-layered earth models are tested. Compared with traditional numerical filter method, the result shows that the direct integration technique can improve the frequency response simulation accuracy of electromagnetic soundings for 1D earth, and gives calculating base of obtaining the very late time electromagonetic responses with high accuracy.