A Multicomponent Seismic Investigation of Natural and Induced Fracturing, Saskatchewan, Canada

Edward Andrew Nicol

Fractures in the subsurface are known to impact seismic imaging. This study focuses on multicomponent, time-lapse analysis of fracture-induced anisotropy in the Devonian Dawson Bay Formation in southern Saskatchewan. The baseline and monitor, PP and PS seismic volumes were divided into 4 sub-volumes consisting of a 45 degree stack of source-receiver ray paths.

Weak azimuthal anisotropy was observed through the interpretation of these volumes. Travel-time analysis located areas which are interpreted to exhibit a higher density of preferential fracturing which appears to be related to mining operations. Vp/Vs analysis, through the registration of PP and PS horizons, confirmed the presence of a high Vp/Vs anomaly which is interpreted to be caused by fractures networks without a preferential orientation within the Dawson Bay Formation in the centre of the survey area. Seismic attribute analysis was used to determine that fractures extend vertically from the Dawson Bay Formation to the top of the Souris River Formation.