Speaker: Dan Kahn, Devon Energy
Co-Authors: Joe Teff, Ken Silver, David Langton and Eric Hart, Devon Energy

Devon Energy conducted a Surface Microseismic Monitoring Project to compare various microseismic acquisition geometries targeting the Eagle Ford (EGFD) formation.  Two horizontal wells were drilled, Well A at a depth of roughly 12,350 feet with a lateral length of ~5,500 feet in the Upper EGFD, and Well B at a depth of roughly 12,500 feet and extending ~6,000 feet in the Lower EGFD.  The goal of the Microseismic Monitoring Project was to benchmark different acquisition geometries when monitoring the hydraulic fracture stimulation in Well A.

In benchmarking surface array acquisition geometries, the objective is evaluated not only in amount of hypocenters located and the precision and accuracy of those events, but the cost, adaptability and added source processing that can be done with the acquired data.  To assess several geometries, the hydraulic fracture stimulation of Well A was monitored using a patch array and a radial array.  The events imaged by these arrays were compared to a 3rd array consisting of a much denser sampled 3C 3D seismic geophones.

The radial array design consisted of ten radial arms evenly spaced emanating outward 18,000 to 24,000 feet from the well head.  The patch array consisted of thirty-one patches, forty-eight instruments per patch in sets of twelve, evenly spaced throughout the same area ranging from 3,000 to 25,000 feet from the well head.  In monitoring a frac, both layouts were tested for precision and accuracy of hypocenters (x,y,z) and source mechanisms.  The sampling of the radial array was superior, determining more hypocenters with higher accuracy and a better-constrained velocity model.  The patch array appears to have been too sparsely spaced with many patches too far from the well. Patches located on the nodal plane also provided no contributions to the focal mechanism calculations.

From this project, a potential strategy for both the patch and radial array can be achieved with proper planning for the area.   Well-designed acquisition geometries can in turn increase the knowledge provided by microseismic monitoring for reservoir characterization.  We look forward to pursuing these questions on this project and as well as on future projects.

Speaker Biography: Dan Kahn, Devon Energy
After graduating from Brown University (2001) with a B.S. in Geology/Physics/Mathematics, Dan Kahn received his M.S. in Geophysics from Georgia Institute of Technology (2004) with a thesis, Concentration of Methane Hydrate: A Study of the Blake Ridge. He then earned a Ph.D. from Duke University (2008), working at the Krafla, Iceland geothermal station and the Basel Hot Dry Rock Project with a dissertation, Crack Propagation in Hydro-Fractured Reservoirs: A Study Using Double-Difference Location Techniques. Dan worked at Exxon as a Senior Geophysicist (2008-2011), during which time he did structural and stratigraphic interpretation of the Austin Chalk Trend and was lead survey designer for the Ranridge and Papua New Guinea projects. He was an Exxon Gold Service Medallion recipient (2008). Dan joined ION Geophysical in 2011, where he specialized in the characterization of unconventional reservoirs through microseismic fracture imaging and analysis. He was co-developer ION’s Java-based microseismic tool kit, authoring 7 patents. Dan moved to Devon in 2015 where he is responsible for overseeing data acquisition and analysis for the description of the dynamics of unconventional reservoirs, including microseismic, magnetotelluric, time domain electromagnetics, and optical fiber techniques. Dan was also a USA Olympic Trials qualifier in the Marathon with the “A” standard.

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