Development of a Magnetically Coupled Borehole Source for Use in Dry Gas Environments

75969S Unconventional gas and oil reservoirs (including tight gas sands, coalbed methane, oil and tar sands and shales) are expected to play a vital role in providing secure sources of energy in North America. Subsurface seismic imaging will be required for the proper delineation, completion, and production of these unconventional reservoirs., and powerful borehole sources of seismic energy will be a critical element of the imaging process. This project will develop a magnetically-coupled source to cost effectively impart high levels of seismic energy into the wellbore. Phase I designed and built a small-scale prototype, which produced a definitive, measurable output. The prototype was then reduced in size and operated in cased wells in the oil sands of Canada. The perforance exceeded that of current industry-standard sources. In Phase II, the source will be scaled-up, implemented, and tested to achieve the most powerful prototype source that can be cost-effectively produced. Commercial Applications and Other Benefits as described by the awardee: The new source is expected to be a critical-path element for the widespread use of subsurface borehole imaging. Specific applications should include: (a) crosswell seismic at 2 km between wells with receivers operated inside production tubing; (b) reverse 3-D VSP in environmentally sensitive areas and rough terrain; (c) high power, cost effective acoustic stimulation; and (d) moving surface seismic below the weathered layer into low-cost horizontal wells.