The Deep Madden Field, a Super Deep Madison Gas Reservoir, Wind River Basin, Wyoming

Clyde H. Moore, Connie Hawkins, Jeff Crockett

Madison dolomites form the reservoir of a super deep, potential giant sour gas field developed on the Madden Anticline immediately in front of the Owl Creek Thrust along the northern rim of the Wind River Basin, central Wyoming. The Madison reservoir dolomites are presently buried to some 25,000 feet at Madden Field and exhibit porosity in excess of 15%. An equivalent dolomitized Madison sequence is exposed in outcrop only 10 miles to the north on the hanging wall of the Owl Creek Thrust at Lysite Mountain. Preliminary comparative stratigraphic, geochemical and petrologic data, between outcrop and available cores and logs at Deep Madden suggest: 1) early, sea level-controlled, evaporite-related dolomitization of the reservoir and outcrop prior to significant burial 2) bot outcrop and deep reservoir dolomites underwent significant recrystallization during a common burial history until their connection was severed during Laramide faulting in the Eocene; 3) while the dolomite reservoir at Madden suffered additional diagenesis during an additional 7-10 thousand feet of burial, the pore systems between outcrop and deep reservoir are remarkably similar.

The Deep Madden Field is presently shut-in awaiting a gas plant and further developmental drilling. The sequence stratigraphic framework and the diagenetic history of the Madison strongly suggests that outcrops and surface cores of the Madison in the Owl Creek Mountains could be useful in further development and detailed reservoir modeling of the Madden Deep Field.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995