Abstract: Development of Mesaverde Group Reservoirs, Grand Valley-Parachute-Rulison Fields, Piceance Basin, Colorado

Terry R. Barrett, Kurt M. Reinecke

Over the last 14 years extensive development of long-life and low risk Mesaverde Group reservoirs has occurred along the Colorado River between Parachute and Rifle, Colorado. The Mesaverde Group is subdivided into an underlying sequence of blanket-like, marine regressive sandstones called the Iles Formation, and an overlying sequence of multiple lenticular, fluvial sandstones and basal Cameo coalbeds called the Williams Fork Formation. The extent of the gas accumulation in the low permeability (tight) Mesaverde Group reservoirs in the area of Grand Valley-Parachute-Rulison fields is best described by the basin-centered gas-trap model. Based on mud-log shows, the top of the gas-saturated section rises stratigraphically as the 3300^prime thick Mesaverde section dips into the deep basina trough. Localized, but high quality, gas reservoirs do occur in that part of the Mesaverde section that lies above the main basin-centered gas accumulation.

Early development techniques of the Mesaverde Group involved drilling a vertical wellbore and completing the multiple tight sandstone reservoirs with small (<100,000 lb) sand propped hydraulic fracture treatments spread over 700^prime to 1100^prime long intervals. Later, using limited entry techniques, the length of the treatment interval was shortened to 350^prime and the amount of proppant used was increased (>300,000 lb). In an effort to recover more of the gas in place the feasibility of utilizing 1) horizontal drilling for the blanket-like reservoirs in the Iles, 2) high-angle drilling for the multiple lenticular reservoirs, and 3) 80 acre well spacing for the vertical wellbores is currently being evaluated.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994