Ultra-Deep Logging for Monitoring CO2 Sequestration

Sequestering CO2 in geologic formations in the earth is a promising approach to reducing CO2 in the atmosphere and thereby slowing global warming. In these formations, it is important to understand where the CO2 is going and to assure that the sequestered CO2 is permanently contained. Three-dimensional surface seismic methods could provide valuable information, but the vertical resolution of these methods is typically 50 to 100 feet or greater, making it impossible to see the small-scale reservoir features that may determine the CO2 flow paths. Crosswell seismic is one method that has the requisite vertical resolution, but two wellbores are required to conduct the survey. Single well imaging, which involves placing both a seismic source and a receiver in the same wellbore, has been suggested as a remedy. However, several factors have limited its utility: downhole source strength, self-noise, and imaging geometry. This project will demonstrate the feasibility of deploying a source and receiver in close proximity to determine reservoir size and heterogeneity within a radius of deep investigation around a wellbore. The concept will be evaluated through an actual field test. Commercial Applications and other Benefits as described by the awardee: The direct measurement of the properties of geologic formations would be useful in tracking the progress of CO2 injection in a sequestration program. Additionally, the technology should be useful in reservoir characterization, development, and field revitalization.