消除VSP资料上井壁-套管耦合不良的干扰

THE ELIMINATION OF INTERFERENCE DUE TO INCORRECT WELL WALL-CASING COUPLING FROM THE VSP DATA

大庆石油管理局物探公司

在下套管井中进行VSP采集,时常会碰到因水泥固井质量不佳,造成套管与井壁之间不能很好地耦合,使所测VSP资料受到干扰。本文论述了这种干扰的产生过程及其在监视记录上的特征。通过实例说明了用二维速度滤波方法可以消除VSR资料上的这种干扰波,处理后的VSP解编记录完全可同正常井中采集的VSP资料媲美。

While performing VSP data acquisition in the borehole with casings, it happens every so often that due to the collapse of adjoining rock of well wall or poor quality of cementation, it results in the unacceptable coupling between casing and well wall and hence the VSP data are met with interference. The paper expounds theoretically how such an interference is engendered and its characteristics shown on the monitor record. From example given, it elucidates that such interference can be removed from VSP data by using 2-D Filtering method. The multiplexed record after being processed is as good as the VSP data normally collected from downhole.