Abstract

Greater Monument Butte oil field encompasses about 110,000 acres in Duchesne and Uintah counties, Utah, and has an estimated 1 billion to 2 billion barrels of oil in place. The field has 73 million barrels (MMBO) of probable reserves and is currently 70% proved undeveloped. It will take about 10 to 15 years to develop the field at the current level of drilling on 40-acre well spacing. Recent drilling spaced at 20 acres per well has successfully tapped banked oil, found new pay, improved sweep efficiency, and accelerated recovery from the Monument Butte waterflood. Infill drilling could result in 1000 more locations extending the drilling to 30 years at current levels. Infill drilling may result in an additional 4% to 6% recovery of the original oil in place (OOIP).

Monument Butte Northeast (MB-NE) waterflood unit is one of 25 units in the Monument Butte Field. The unit is similar in size and reserves to most of the units in the field. The MB-NE unit was studied to determine the potential for CO₂ enhanced oil recovery (EOR). Modeling indicates that CO₂ EOR could increase the ultimate recovery to 20% to 30% of the OOIP, and perhaps up to 50% of OOIP in some portions of Greater Monument Butte Field. At 30% recovery of OOIP, this would be an additional 300 MMBO more than expected from primary and secondary waterflooding.