Abstract: Relationship Of Salt-Solution Features to Oil and Gas Entrapment and Surface Anomalies, Denver Basin, Western Nebraska

OLDHAM, DAVID W.
Consultant, Morgantown, WV, and DIFFENDAL, ROBERT F., JR.
Univ. of Nebraska, Lincoln, NE

Integration of surface and subsurface studies across the southern part of the Nebraska panhandle reveals a spatial relationship between drainage anomalies, oil and gas production, and the location of dissolution-induced Permian salt outliers.

The Sidney Trough and subsidiary synclines are rootless salt solution-collapse features which mark the regionally updip limit of the Cretaceous D-J Fairway. The location of the Sidney Trough coincides with that of the Rush Creek - Lisco structural basin, a surface feature which is marked by local reversal in dip at the Miocene Ogallala Group level, by dips in PlioceneQuaternary river ten-ace elevations, by closed surface depressions, and by the abrupt northward change in flow direction of Rush Creek, a tributary to the North Platte River.

The easternmost limit of salt coincides with a regional subsurface structural depression located just east of the gas-productive Big Springs and Oshkosh-Lewellen anticlines. This depression is associated with drainage anomalies along Ash Hollow Creek and other tributaries to the North Plane and by surface depressions near Big Springs.

The apparent relationship of salt solution-collapse to Cretaceous reservoir-level structure and to surface anomalies implies that much of the deformation occurred relatively recently. This suggests that surface mapping may be useful in delineating structurally-controlled oil and gas prospect leads in under-explored areas of the Denver basin as well as to other areas which are prone to subsurface dissolution of salt.

AAPG Search and Discovery Article #90930©1998 AAPG Eastern Section, Columbus, Ohio