By OGJ editors
HOUSTON, Jan. 28 -- ExxonMobil Corp. plans to start acid-gas injection at its Shute Creek gas treatment plant in LaBarge, Wyo., this spring.
The $400 million project will hike inlet capacity of low-btu gas at the Lincoln County plant by almost 11%, reduce carbon dioxide venting and sulfur dioxide emissions, and cut sulfur-handling costs.
A 110-Mw cogeneration facility that started up as part of the same project in early 2004 has already resulted in considerable cost savings because the company now generates its own power.
The Shute Creek plant treats the mostly nonhydrocarbon gas produced in ExxonMobil-operated federal units in Fogarty Creek, Lake Ridge, and Graphite fields, discovered in 1975-86 in the Green River basin. Fogarty Creek is the state's third largest gas field by full production volume.
ExxonMobil has 100% interest in the plant, which started up in 1986, and in the Mississippian Madison carbonate formation in the three units.
The US operations of ExxonMobil, the world's largest wholesale marketer of helium, produced nearly 4 MMcfd of helium in 2003.
Shute Creek operation
Upon the start of acid-gas injection later this year, Shute Creek plant inlet capacity will rise to 720 MMcfd.
The raw gas from the Madison at 16,000 ft is 22% methane, 65% CO2, 7.4% nitrogen, 5% hydrogen sulfide, and .6% helium. Individual well rates are 30-40 MMcfd.
Methane and helium from the plant are sold. Of the plant's output of 250 MMcfd of CO2, 80% is sold to three operators of enhanced oil recovery projects in Wyoming and Colorado.
Anadarko Petroleum Corp. expects to take nearly all of the rest of the available CO2 when it boosts injection into its Salt Creek and West Sussex oil fields in the Powder River basin later this year.
ExxonMobil has drilled two wells with state and US Environmental Protection Agency approval to be used to inject a combined 60-67 MMcfd of 65% CO2 and 35% H2S below the Madison gas-water contact at 17,500 ft. ExxonMobil will burn a methane-CO2 mixture to power the injection compressors.
Injecting the H2S will allow the company to shut down the aging sulfur recovery unit, which has high operating and maintenance costs, and exit the weak market for sulfur.
The extracted CO2 volume will not increase because treatment severity and compression would be too costly. Relatively small volumes of CO2 will continue to be vented or flared under annual review by the Wyoming Oil and Gas Conservation Commission.