Steven G. Natali¹, Peter Dea¹, Fred Barrett², Roy Roux²
(1) Barrett Resources Corporation, Denver, CO
(2) Barrett Resources Corporation

Abstract: Cave Gulch 3-D Survey, Wind River Basin, Wyoming

The Cave Gulch field, with proven reserves in excess of 600 BCF, is one of the most significant Rocky Mountain gas discoveries of this decade. 3-D seismic acquisition proved vital to the proper imaging and development of the field. The geology setting and sequential field developments have been previously outlined in detail. (Dea, Barrett, Natali, Roux, 1998).

A 21.5 square mile 3-D survey was acquired jointly by Barrett Resources and Chevron Corporation immediately following the Cave Gulch #1 discovery well in November, 1994. The survey was used to explain the unanticipated results of the first two offsets to the discovery well, and guided the successful drilling that has occurred since.

Due to the strong lateral velocity variations caused by the overlying sediments and granite being carried in the hanging wall of the Owl Creek Thrust, the image provided by depth migration was radically different from the time migration. Check shot surveys acquired in successive wells were used to update the three-dimensional velocity model that drove the depth migration. With successive iterations, the depth image changed, permitting accurate drilling of increasingly deep targets.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana