Print this pageABSTRACT: Gas in the Castlegate Sandstone, Uinta Basin, Utah and Douglas Creek Arch, Colorado
John C. Osmond
The Castlegate Sandstone, a tongue of the Upper Cretaceous Mesaverde Formation, can be traced from central Utah to the Colorado border in the Book Cliffs on the south flank of the Uinta basin. It can be traced into northwestern Colorado in the subsurface and in outcrops on the south flank of the Uinta Mountains and the Axial basin anticline.
In central Utah the sandstones were deposited by braided east-flowing streams and pass eastward into delta-plain and northeast-trending shoreline sandstones enclosed in the Mancos marine shale.
Gas has been produced from porous and permeable Castlegate shoreline sands in eight small fields in eastern Utah and on the Douglas Creek arch in western Colorado at depths of 1100-4500 ft. The traps depend on structural closure, and several of the fields are closed against faults. The faults have up to 330 ft of throw and die out in the Garden Gulch Member of the Eocene Green River Formation.
Numerous wells in the Uinta basin have had shows in the Castlegate, and several tested it; but there is no economic production to date.
New Castlegate gas fields will be found by mapping the shoreline facies in the subsurface of eastern Utah and western Colorado and looking for closure against faults that do not cut to the surface. There is also the good possibility of gas in stratigraphic traps where the shoreline sands cross anticlinal folds.
AAPG Search and Discovery Article #91002©1990 AAPG Rocky Mountain Section Meeting, Denver, Colorado, September 16-19, 1990