Microseismic arrays complement downhole data acquisition
ESG Solutions has introduced its new Hybrid Downhole/Near-surface microseismic solution. Recent concerns surrounding the potential of oil and gas operations to induce larger magnitude events has highlighted a need to accurately detect seismicity greater than M0 in addition to small scale microseismic activity.
ESG’s patent pending Hybrid acquisition configuration deploys near-surface or shallow buried microseismic arrays to complement downhole acquisition, providing a fully integrated solution to assess large and small magnitude seismicity in one comprehensive system.
Seismic networks deployed to monitor production related activity in reservoirs are designed to detect and analyze small scale micro-earthquakes. “In particular, hydraulic fracturing and cyclic steam injection activities generate thousands of micro-earthquakes with magnitudes in the range of -M4 to M0. However, the geophones typically used in these networks may not be optimized to record the lower frequency signals and longer window lengths associated with larger magnitude events ranging from M0 to M4.”
ESG’s new Hybrid solution combines near-surface or shallow buried microseismic arrays with a network of vertical downhole toolstrings. Not only does this configuration increase the physical field of coverage, but the use of accelerometers as near-surface sensors more accurately measures large magnitude events, widening the range of magnitudes which can be successfully evaluated with a single microseismic system. “This configuration provides for truly broadband microseismic acquisition, spanning signals from -4 to +4 in magnitude,” says Urbancic.
ESG's Hybrid downhole/near-surface solution has been successfully applied to hydraulic fracturing operations throughout North America.