Multicomponent processing: South Casper Creek, Wyoming

Mark Paul Harrison

The Casper Creek South Field in Natrona County, Wyoming, is formed by two doubly-plunging anticlines having dips of as much as 30 degrees. A multicomponent reflection survey was conducted across the field by Union Oil of California (UNOCAL) in 1988, in which data from a dynamite source were recorded in the vertical, radial, and transverse directions. These data have since been donated to the CREWES Project for analysis.

It was found in processing this data set that considerable energy exists on the crossline component. Geophone rotation tests indicate maximum energy on the radial component is achieved by a 22 degree counter-clockwise rotation of the horizontal components away from the direction of acquisition. This rotation positions the radial and transverse components closer to the direction of maximum dip and strike. The section obtained from the rotated radial component was found to have slightly greater reflection continuity, while the rotated transverse component had little recognizable signal.

The application of P-SV dip moveout to the rotated data was able to improve the continuity of deeper reflections over that produced by depth-variant binning. Migration of the DMO-corrected section gives a result which correlates structurally to the migrated vertical-component stack, but has much lower signal bandwidth and signal-to-noise level.