Analysing the Pikes Peak multi-offset VSP dataset

Carla A. Osborne, Robert R. Stewart

As part of a continuing long-term study, a multi-offset VSP survey was shot in a test well at Pikes Peak, Saskatchewan during September 2000. Three-component data was recorded at a series of six offsets with an average lateral source-receiver separation of 90m. The data has a high signal-to-noise ratio, and the zero-offset data has already been found to tie well with a 2D seismic line conducted nearby (Xu, 2001). However, the dataset is still a challenging one, especially with regards to processing the farther offsets. High-frequency noise and static shifts due to toolclamping problems initially suggested spurious geological information, while upgoing arrivals on the farther offsets revealed important new subsurface velocity information. This dataset emphasizes the importance of survey and borehole information combined with quality control of each processing step for the ultimate accuracy of the seismic image and accuracy of the rock properties derived from the data.