SBIR Phase II: Time-Lapse P- and S-Wave Monitoring of Fluid Flow

Fourth Wave Imaging Corporation, Aliso Viejo CA

Investigators

Abstract

This Small Business Innovative Research (SBIR) Phase II project concerns the use of time-lapse seismic P-wave and S-wave data simultaneously to obtain seismic monitoring images of fluid-flow saturation and pore pressure in subsurface reservoirs. Time-lapse seismic using P-waves alone may not always produce reliable discrimination between fluid-flow saturation changes and pore pressure changes since this information is contained in the large-reflection- angle portion of the P-wave seismic data, which can easily be contaminated by noise and can be subject to data acquisition aperture limitations. Using S-waves in addition to P-waves in the time-lapse analysis can provide more accurate inversion results, thereby improving the reliability and robustness of fluid-flow saturation and pressure estimates. The critical commercialization research and development issues in this project are: (1) mode-equalization image processing and pre-conditioning of the P-wave and S-wave data sets to make them suitable for simultaneous quantitative inversion and analysis; ( 2) computation of optimal seismic attributes and robust pressure-saturation inversion of these attributes; (3) testing and bulletproofing these techniques on a real field data set to overcome the inevitable practical data issues; and (4) developing the tools in an interactive GUI-based software package to provide a workflow that facilitates integrated numerical computation and human interpretation. Commercial applications of proposed research will include accurate mapping of bypassed oil, monitoring of costly injected fluids in hydrocarbon reservoirs and global-warming CO2 sequestration projects. It will have applications in the monitoring of ground water reserves, contaminant plumes and environmental clean-up activities. Medical imaging is another potential market target use of elastic waves as they could yield superior results over acoustic waves alone. Commercial and societal benefits include extending the life of existing oil and gas fields, thus reducing the need for exploration in environmentally sensitive areas and improving the nation's energy security.