Assessing Technical and Economic Recovery of Oil Resources

2. Wasson Field, Denver Unit. The Wasson Field is located on the southern limit of theNorthwest Shelf of the Permian Basin in Yoakum County, Texas, about 80 milesNNW of the city of Midland, Figure 24. As seen in Figure 27, Wasson Field Areawith San Andres Formation Producing Units, the Denver Unit is one of seven units ofthe huge Wasson Field. The greater Wasson Field covers over 68,000 acres andholds an estimated 4.5 billion barrels of OOIP in the MPZ. The Denver Unit lieswithin the southern portion of the Wasson Field and is the largest of the seven units,with a reservoir area of 27,848 acres, a MPZ OOIP of 2,372 MMbbls, and a ROZ OIPof 1,039 MMbbls. The MPZ is at a depth of 5,200 feet and has an average netthickness of 141 feet. The ROZ is at a depth of 5,380 feet and has an average netthickness of 150 feet, Figure 28, Wasson-Denver Unit Input Parameters Summary.The Denver Unit has 1,293 active production wells and 1,198 injection wells.Cumulative MPZ oil production for the Denver Unit is 1,211 MMbbls with 169 MMbblsof this due to tertiary CO 2 flooding. A series of CO 2 -EOR ROZ pilot anddemonstration projects have been underway in this reservoir unit since 1991,contributing to the above cited oil production from CO 2 flooding.3. Wasson Field, Bennett Ranch Unit. As shown in Figure 27, the Wasson Bennett RanchUnit is located in the northeastern portion of the greater Wasson Field. It has areservoir area of 7,027 acres, a MPZ OOIP of 288 MMbbls and a ROZ OIP of 240MMbbls. The MPZ is at a depth of 5,100 feet and has an average net thickness of90 feet. The ROZ is at a depth of 5,305 feet and has an estimated net thickness of150 feet, Figure 29, Wasson-Bennett Ranch Unit Input Parameters. The BennettRanch Unit has 81 active producing wells and 75 actual injection wells. CumulativeMPZ oil production for the Bennett Ranch Unit is 75 MMbbls with 3 MMbbls of thisdue to tertiary CO 2 flooding. A portion of the oil being recovered by CO 2 flooding isdue to the recently started CO 2 -EOR ROZ pilot.3-12 February 2006