连续介质变起始速度V₀的方法

METHOD FOR ALTERING THE INITIAL VELOCITY V₀ OF CONTINUOUS MEDIUM

江汉石油管理局地调处

连续介质的起始速度V₀由浅层到深层都为固定一个常数的作法,是不符合实际情况的。但它最大的优点之一是比其它介质的假设(均匀介质除外)简便得多。然而,引入平均梯度法以后,虽然其速度梯度随深度不断变化,但V₀还是定值,以致在射线的出射角稍大的情况下,就会出现等时线与射线不正交的现象。那么,怎样去劣留良呢?本文提出一种分段拟合的设想。

It is not conform reality to assume the initial velocity Vo of the continuous medium to be a constant value in different depths. Though it being the case, the above assume has still some advantages. One of which is that the assume is more simple than those for the other mediums. As for the homogeneous medium, it should be regarded as a different matter. In the method of average gradient, though the velocity gradient various with the depth, the V0 is still a constant. Hence, for the bigger emergence angle, the reflected rays will not orthogonalize with the curve of isotime. Plow to solve this problem properly and get a better result? The following suggestion about piecewise fitting might be a feasible way.