Preliminary processing and analysis of the Blackfoot walkaway VSP

Chuandong (Richard) Xu, Robert R. Stewart

In November 1997, the CREWES Project with assistance from Boyd Petrosearch Consultants Ltd. and PanCanadian Petroleum Ltd. conducted a high-resolution 3C-2D seismic survey combined with a walkaway VSP in Blackfoot field. This VSP survey was acquired in well BF09-08-23-23W4 by Schlumberger of Canada, using a 5-level 3-component ASI downhole receiver string with 15 m receiver interval and dynamite sources. Ten deep levels from 1425m to 1560m are processed. All procedures in the processing flow are performed in the shot gather domain. A median filter is used to separate downgoing and upgoing wavefields. A deconvolution operator is extracted from the downgoing wave and applied to the upgoing wave. The VSPCDP map ties in quite well with the migrated CMP section from the 2-D surface seismic line which is acquired simultaneously. The VSP AVO gather does not show an obvious amplitude anomaly at the position of target channel.