Development of Glenrock Area Fields, Converse County, WY

Abstract

In 1916, shallow Shannon Formation oil was discovered on an “oil claim” on University of Wyoming Land Grant acreage near Parkerton about 20 miles east of Casper. This discovery would become the huge Big Muddy field, rivaling the Salt Creek field in size and activity. Development soon included the Frontier 2nd Wall Creek, and Dakota Formations. Since then, the Glenrock fields have produced more than 140 MMBO. Revenues from Big Muddy State leases allowed University of Wyoming to survive the depression and construct several buildings at a time when their very existence was in doubt. Poor earlyday production practices led to substantial waste. Conoco built the Glenrock refinery in 1925 to process crude from Big Muddy field and other areas. A deep test to the Madison Formation in 1935 found no significant shows below the Dakota. By 1943, the Big Muddy field was essentially depleted after having produced about 30 MMBO. Dakota and Muddy Formation production was discovered in the South Glenrock fields around 1950, and water flooding began in the 1960s. Encouraged by a 1973 lowRocky Mountain Section – AAPG: 2019 Annual Meeting 38 tension pilot test at Big Muddy, Conoco and DOE teamed up for an unsuccessful Frontier surfactant flood in the 1980s. In 2007, Rancher Energy purchased the Big Muddy, South Glenrock and South Cole Creek fields for CO2 tertiary recovery. Nitec LLC estimated that CO2 flooding could potentially recover in excess of 10,000 b/d each from South Glenrock and Big Muddy fields. Rancher acquired a take-or-pay CO2 contract and conducted pipeline and facility FEED studies. In 2009 Rancher attempted to join forces with Elk Petroleum, whom they saw as being likely to get a better CO2 contract. In 2011, Queensland-based Linc Energy purchased the fields from a reorganized Rancher, which was recovering from a hostile takeover. Best known for its underground coal gasification (UCG) technology, Linc hoped to conduct miscible floods using waste CO2 from their UCG projects in the Powder River Basin. Linc acquired an interruptible CO2 contract from Exxon, built a line tap, and planned to truck CO2 from Jeffrey City to Glenrock. Linc planned CO2 injection rates of up to 30 MMCFD after completion of the CO2 injection infrastructure. In 2011, Linc unsuccessfully attempted a Dakota CO2 cycling (huff-n-puff) project in South Glenrock B using 500 tons of CO2. Linc subsequently sold all of the Glenrock properties to Glenrock Energy. In 2016 Glenrock Energy began focusing on re-development and optimizing depleted reservoirs. A large high-resolution 3-D seismic acquisition program has been completed. To date, there is no public information available on the company’s re-development plans or results of the 3-D seismic program.

AAPG Datapages/Search and Discovery Article #90357 ©2019 AAPG Rocky Mountain Section Meeting, Cheyenne, Wyoming, September 15-18, 2019