利用VSP资料反演地层层速度的一种新途径

A new way to invert interval velocity by using VSP data

石油大学CNPC物探重点实验室,北京 102249

CNPC Key Seismic Laboratory of University of Petroleum, Beijing 102249, China

利用VSP资料受干扰程度小,信噪比高,高频成分丰富以及能精确地分离出上、下行波的特点,提出了一种利用VSP资料上、下行波的波场值反演深部地层层速度的方法。该方法首先利用VSP资料提取地下地层的反射系数,然后利用地层反射系数反演出各个地层的层速度。与VSP资料解释的层速度相对比,该方法反演出的地层层速度的分辨率较高,且只与资料的采样率有关,与VSP测井的接收点距无关。利用该方法还可以反演出VSP测井接收范围之外的上、下地层的层速度(这些层速度不能通过VSP资料解释得到)。

This paper presents a method of inverting interval velocity of deep layers with upgoing and downgoing waves of VSP data. The method firstly determines layer's reflectivity from VSP data,and then inverts interval velocities of various layers from the resulted reflectivitis. Comparing to the interval velocity from VSP data interpretation, the resulted velocity is of higher resolution, and only subject to sampling rate and independent of receiving distance. The method can also be used to determine the velocities of overlying and underlying layers beyond the range of VSP log.