Publications

• We think of CO2 as the greenhouse gas (GHG) causing global warming.
• The Stern Report and the several IPCC (Intergovernmental Panel on Climate Change) reports are gaining acceptance.
• In its most recent report (AR4 Synthesis Report November 17, 2007) the IPCC has written: Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.
• The report goes further to say: Most of the observed increase in globallyaveraged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations.
• The Supreme Court on April 2, 2007 in a 5 to 4 decision decided that CO2 was a pollutant and the EPA could regulate auto emissions of the GHG (Chemical & Engineering News, April 3, 2007).

A reprint of Formation Water Resistivities originally compiled by Don Cardinal (1984) is now available on the EORI website. This publication is a valuable resource for establishing Rw values necessary for calculating oil and water saturations from wireline logs.

A reprint of Formation Water Resistivities originally compiled by Don Cardinal (1984) is now available on the EORI website. This publication is a valuable resource for establishing Rw values necessary for calculating oil and water saturations from wireline logs. Data are compiled by basin and include: well name and location, formation, depth, source of the water, Shut-in-Pressure, and measured water resistivity.

CO2– EOR has been an important part of the oil industry for well over 50 years. The firstCO2 flood in Wyoming (1986) continues today at Lost Soldier/Wertz Fields (Baroil). Since 1986 incremental oil production from CO2- EOR is approximately 150 million barrels with severance tax revenue to the State of over $400 million ($50/bbl oil price).

The CO2 used to recover oil is part of a “closed-loop-system”. The CO2 is injected, separated from the produced oil, recycled, and reinjected. Through the life of the project, all CO2 injected (purchased and recycled) is stored in the reservoir.

CO2 is an expensive commodity for EOR with an approximate cost of ~ 2% of oil price (WTI)/MCF. Some floods in Wyoming have purchased well over 200 MMCF/Day - over $300,000/day just for CO2.

The rock layers surrounding Alcova Lake are not only breathtaking to see, they are also windows to a portion of the earth’s history. This guidebook hopes to introduce anyone interested to a brief explanation about what the geology is revealing.

EORI shares this guidebook as part of its commitment to facilitating technology transfer through publications and oral presentations.

View Associated High Resolution Maps

At Rozet Field, the lack of abundant core analyses or modern logs necessitates the adoption of more assumptions than usual in order to estimate OOIP and remaining recoverable reserves. Two different methods for calculating the recovery efficiency of the waterflood were applied withinnine 5-spot patterns resulting in maximum rates of 40% and 30% respectively. Average recovery factors in the combined 5-spot patterns are 27.5% and 24.4% respectively. Both values indicate the waterflood is probably not as effective as it could have been when compared to similar fields producing from the Muddy Formation.

The calculated OOIP for the Muddy Formation at Rozet is about 74.7 million barrels, of which a little over 19 million barrels have been recovered. The recovery factor for the field is then about 25.5%. If a 40% recovery factor is achievable with an efficient waterflood, then the remaining recoverable oil reserves from the Muddy Formation at Rozet Field are approximately 10.8 million barrels. This magnitude of a target should warrant further investment in improved and enhanced recovery methods there.

At nearby Windmill Field, secondary recovery has yet to be implemented in the Muddy reservoir. Wireline log suites containing porosity logs in this field enable more confidence in the geologic mapping and OOIP calculations than at Rozet. Cumulative oil production there is 677,735 barrels, resulting in a recovery factor of about 14.8%. Assuming the clay content does not vary significantly from that observed at the adjacent Rozet Field, a well-designed waterflood should be effective at increasing production in Windmill Field. If a recovery factor of 40% could be achieved by implementing secondary recovery efforts there, it could result in the production of an additional 1,157,465 barrels of oil.

• Nine different reservoirs in seven fields have employed fieldwide CO2 EOR in Wyoming.
• Between 2010 and 2020, incremental oil recovery from the nine CO2 EOR projects accounted for over 10% of Wyoming’s total oil production.
• Wyoming is not constrained by CO2 sources that can be used for EOR projects.
• Wyoming is also not constrained by fields potentially amenable to CO2 EOR.
• Wyoming is not constrained by pipeline capacity for additional CO2 transport, but is hampered by the existing pipeline system not reaching many of the best-potential fields, especially in the Big Horn Basin.
• The most successful CO2 floods resulted from proper reservoir characterization and associated optimized project design. Wyoming has seen incremental oil recovery from individual CO2 EOR projects as high as 18% of OOIP and volumes as high as 30 million barrels.
• Where net CO2 efficiencies could be calculated, CO2 efficiency is as low as 6 Mcf/bbl of incremental oil recovered, which compares very favorably to other successful projects around the world.

Evaluating the effectiveness of products and/or methods that might improve oil and gas production in Wyoming is one of the functions of the Enhanced Oil Recovery Institute (EORI). As part of that effort, EORI sponsored an evaluation of a novel product that reportedly could help reduce the detrimental effects of paraffin precipitation and deposition in oil wells.

This novel product is produced from recycled tires and is under development by a clean-tech company that converts scrap rubber materials into several beneficial products. Although analyses have shown that this product in its current form does contain a significant quantity of aromatic solvents that may act either as inhibitors of paraffin wax deposition or as a paraffin solvent, tests using the novel, tire-recycled oil (TRO) product on three different paraffinic oils from Wyoming oil fields showed that the concentrations of these solvents in the product are insufficient to provide substantial benefits for that purpose.