AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Seismic
Technologies for Unconventional Reservoir Characterization: Wamsutter Field Case Study
(1) North America Gas, BP America Inc., Houston, TX.
(2) E&P Technology, BP America Inc., Houston, TX.
As part of a significant seismic
technology effort, the BP Wamsutter
Seismic
Integration team conducted two extensive field trials during 2006 and 2007- a surface
seismic
field trial and a borehole
seismic
field trial.
The surface seismic
field trial consisted of a world’s-first deployment of cableless full-wavefield single-sensors in a 3D onshore survey. This acquisition delivered a unique high density, full azimuth, 3-component dataset for analysis. Very careful processing was applied to the full wavefield
data
to optimize resolution and retain robust amplitude and azimuthal information. In addition to conventional full stack
seismic
attributes, analysis of velocity anisotropy, AVO (Amplitude with Offset) and AVOAz (AVO with Azimuth) attributes calibrated to well
data
have greatly increased our understanding of this tight gas sandstone reservoir.
The borehole seismic
field trial consisted of a 3D VSP (Vertical
Seismic
Profile), as well as a four-well crosswell
seismic
campaign. The 3D VSP was acquired to further our understanding of
seismic
technical limits within the field, demonstrate the value of enhanced temporal resolution to reservoir characterization, and to test the viability of borehole
seismic
as a development tool for infill planning. Pre-acquisition modeling allowed theoretical limits of vertical
seismic
resolution to be compared to existing
seismic
data
. Processing of the field
data
demonstrated that significantly higher frequencies (double the bandwidth) were achieved with the 3D VSP, as compared to existing and newly acquired surface
seismic
data
. Prestack depth migration of the 3D VSP yielded high quality imaging results, which have allowed enhanced stratigraphic description of a very complex, heterogeneous reservoir.
Analysis, interpretation
and integration of the surface
seismic
and borehole
seismic
data
have greatly progressed our understanding of the potential increase in the value of “designer” or fit-for-purpose
seismic
across the Wamsutter Field and beyond. Learnings from the field trial are already impacting the onshore
seismic
strategy both within the Wamsutter field and across BP’s tight gas business.