Horizontal Drilling Potential in Utah

CHIDSEY, THOMAS C., and CRAIG D. MORGAN, Utah Geological and Mineral Survey, Salt Lake City, UT

A minimum of 18 reservoirs in both producing and frontier areas of Utah are potential targets for horizontal drilling. Horizontal drilling can enhance production in some active fields, revive production in abandoned fields, and discover new fields in areas traditionally overlooked for oil and gas.

Many Utah oil and gas fields produce from naturally fractured reservoirs, a principal objective for horizontal drilling. The Grassy Trail Creek field (Carbon and Emery Counties) is an example of an older field that was revived using horizontal drilling. Between 1982 and 1984, 18 wells with 68 short-radius horizontal laterals were drilled in the Triassic Moenkopi Formation. The eight best wells were completed for an average rate of 127 BOPD per well, twice that of conventionally drilled wells in the field.

Using current technology, fields within the Paradox basin, Uinta basin, and Overthrust belt are also good candidates for horizontal drilling. In the northern Paradox basin, six fields have produced oil from the Cane Creek zone, a fractured organic-rich shale in the Pennsylvanian Paradox Formation. The active Long Canyon field has produced nearly a million barrels of high gravity, low sulfur oil. Neighboring abandoned fields had steep production declines and no associated water, suggesting that additional untapped reservoirs still exist. In the Uinta basin, fractured reservoirs in the Green River and Wasatch formations are the principal candidates. In the Overthrust belt, horizontal drilling could enhance production within the fractured Twin Creek, Nugget, Phosphoria, Dinwoody, and Mad son formations.

Other potential Utah targets include thin reservoirs in the Green River, Ferron, Dakota, and Kaibab formations; algal mounds in the Paradox Formation; and coal-bed methane-bearing units within the Cretaceous Blackhawk and Straight Cliff formations.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)