Abstract

In the summer of 2002 Fasken Oil and Ranch, Ltd., acquired 3D seismic data over a portion of its C Ranch properties located in southeastern Andrews County. In addition to acquiring a “typical” high resolution survey, a separate test survey utilizing 3 component phones was deployed in order to collect mode converted shear wave (MCSW) data. The test survey area was approximately 6 sq. miles in areal extent and situated over Andrews East Strawn Field, a field that had 3 producers and 3 dry holes and produced almost a million barrels of oil. Interpretation techniques completed on the MCSW volume resulted in identifying an anomaly that differentiated the producers from the dry holes that was not detected on the p-wave data. We attributed the amplitude anomaly seen on the MCSW data to isopach differences found in the interval from the Strawn to the Atoka. An interpreter from the Bureau of Economic Geology (BEG) independently concluded the same relationship and went on to discover that frequency decomposition techniques isolated the anomaly that was developed when an isopach value greater that 105’ was encountered. In June of this year, Fasken drilled a step out location to the Andrews East Strawn Field. The well encountered the Strawn structural top equal to prognosis, and found the thickest interval between the top of the Strawn and the Atoka as predicted. The zone containing the main porosity interval was equivalent to the producers in thickness, but unfortunately the well did not have the necessary porosity or facies found in the producers. We are currently integrating the new well information back into our interpretations and modeling the results in order to generate another drilling opportunity to utilize this technology.