Figure 2. (a) Peizotube source, as deployed (left), interior withouto shell (center) and in schematic (right). (b) Hydrophone as deployed on tubing with protector/clamp.

APPLICATIONS OF TECHNOLOGY:

• Continuous crosswell seismic monitoring of
• oil and gas reservoirs
• aquifers for CO2 sequestration

ADVANTAGES:

• Aids in optimizing oil recovery by providing real time and continuous data on reservoir dynamics
• Enables detection of reservoir trends that would be missed by intermittent monitoring
• Eliminates labor costs and production inefficiencies incurred from switching between borehole monitoring and production
• Eliminates the need for dedicated boreholes for wireline deployment
• Minimizes the likelihood of borehole damage caused by retracting and reinserting production tubing

ABSTRACT:

Tom Daley and colleagues at Berkeley Lab have invented a seismic source that can be operated while fluid is being injected or withdrawn from an aquifer or oil well.  The piezotube seismic source offers several advantages that will result in more efficient oil reservoir monitoring and management.  It enables the continuous monitoring of well behavior, delivering data indicating trends that might be missed by time-lapse imagery,  and it eliminates the need to stop production and remove and reinsert tubing from a borehole in order to conduct wireline crosswell monitoring.

The Berkeley Lab source is a hollow tube of piezoelectric material, with an offset center, which can slide onto the production tubing and be clamped in place at any selected location.  Pass-through space is available for cables, allowing other instrumentation to be deployed.  The source can be deployed at injection depth for the duration of an injection.  A piezosource was selected because of durability and data repeatability.  The relatively low amplitude of piezoelectric sources compared with that of mechanical sources can be partially overcome by stacking because the source remains in one location indefinitely.

Researchers acquired good quality seismic data in a recent trial of the new system.  The trial involved continuous crosswell monitoring of CO2 injection without a separate seismic source borehole.  For more information on this trial and the Berkeley Lab seismic source, please see the publication link below.

STATUS:

• Published PCT Patent Application WO2008/127390 available at www.wipo.int. Available for licensing or collaborative research.

FOR MORE INFORMATION:

Daley, T., Solbau, R., Ajo-Franklin, J.B., Benson, S.M., "Continuous Active-source Seismic Monitoring of CO2 Injection in a Brine Aquifer," Biophysics, Vol. 72 No. 5, A57-A61

REFERENCE NUMBER: IB-2317

SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:

• Tube-wave Seismic Imaging and Monitoring Method for Oil Reservoirs and Aquifers, IB-1917
• Identification, Imaging, and Monitoring of Fluid Saturated Underground Reservoirs , IB-1663