Seismic Support Leading to Discovery and Development of Strahm South Field, Forest City Basin, Northeastern Kansas

Abstract

For many decades the Forest City basin has been subject to sporadic exploration activity. Prior to the advent of multifold seismic data acquisition, many significant fields were discovered by integrating subsurface control with shallow core hole data and in some cases spot correlation seismic data. At Strahm South an initial subsurface lead was tested by acquiring 6.25 mi of nominal 12-fold CDP data. This initial survey resulted in field discovery and was augmented by later acquisition of 11.4 mi of development data. Predrilling seismic mapping indicated significant thinning should be expected over a key Lansing-Viola interval and that necessary west dip should be expected at all zones of interest. Development structure mapping at the Top Viola confirms west dip of more than 100 ft. The structural geometry of the field is that of an elongated, faulted and closed feature, slightly over 1 mi long, with productive width apparently less than 1,300 ft. Estimated ultimate recovery from six Viola wells will likely exceed 275,000 bbl. Untested Hunton and Simpson pay remains behind pipe. Though other geophysical and geochemical tools can be of assistance prior to drilling untested structures in this region, multifold seismic resolution is very encouraging. Acquisition geometries incorporating swathmore » shooting and mini 3-D surveys may become effective tools of the future in this historically difficult basin.« less