State-of-the-Art Summary

Where Does CO₂ Come From?
By a large margin, (700 billion tons worldwide, or 97%), CO₂ emissions come from natural sources: animals, volcanoes and other uncontrollable sources. For the last several hundred years—until the 20th century—the earth, primarily through plants and the oceans, has absorbed those emissions, keeping the amount in the air relatively constant. Loss of vegetation and increasing use of carbon fuels, however, is tipping the balance. In the U.S., anthropogenic (man-made) CO₂ emissions from stationary sources are estimated at 2,000 million tons/year (the volumetric conversion is approximately 17 MCF/ton). Transportation would add half that again. The largest source is from electrical generation, nearly half of the stationary total. A single 750 MW coal plant can generate as much as 5 million tons/year. Overall, a relatively small fraction of the sources are of a concentration, size and location to be economically available for enhanced oil recovery (EOR). In their Midland presentation, Excel Energy, a large electric utility, estimated the cost to capture the CO₂ from today's coal plants at $50 to $75/ton, plus transportation costs.

Figure 2 - U.S. CO2 EOR Production, Courtesy Melzer Consulting

Where is the CO₂ Going?
More to the point where is it not going? Or where could it go? As discussed above, 80% of the incremental oil produced by CO₂ flooding comes from the four natural CO₂ domes due to cost and proximity to suitable fields in the Permian basin and Mississippi, which does not help the imbalance of emissions. It effectively takes the CO₂ out of one geological formation and puts it into another. The most recent Oil and Gas Journal survey of enhanced oil recovery projects (April 12, 2004 - to be updated in April 2006 in conjunction with the SPE IOR Symposium in Tulsa) shows 68 CO₂ projects. Collectively, they produce nearly 240 thousand barrels/day and are estimated to sequester around 2 BCF of CO₂ daily (8 MCF per barrel produced). (Figure 2) Fifty-three of those projects are located in the Permian basin and produce over 80% of the CO₂ EOR barrels. A remarkable

But with the Permian CO₂ pipelines running at capacity, the most recent growth has occurred elsewhere, notably in the Denbury East Mississippi pipeline expansion from the Jackson dome to three new CO₂ floods and Anadarko's new projects from the Shute Creek gas plant in Wyoming. The Denbury Free State Pipeline began construction in August 2005 and is scheduled for completion in July 2006. It will run 86 miles at a cost of $50 million, plus another $40 million for the three facilities. It is designed to deliver 270 MMCF/day without compression, up to 450 MMCF/day with compression. The Mississippi CO₂ floods are somewhat different than those in the Permian Basin in that two of them are quite deep, around 12,000 feet, smaller and higher injection pressures, around 3,150 PSI. The other notable new project is Anadarko's expansion in the Powder River Basin. They have constructed a new 125 mile CO₂ line from the Baroil terminus in central Wyoming to the Sussex and Salt Creek fields located to the east and a 33 mile extension to the Monell field in Southern Wyoming at a cost of over $1.2 billion. These three fields are currently producing 20,000 Barrels/day and are expected to peak at 50,000 Barrels/day in 2010. They sequester 175,000 MCF/day of the current Shute Creek plant's 240,000 MCF/day capacity. Anadarko is evaluating a further expansion to the north of Salt Creek to other Powder River fields and ExxonMobil is evaluating an expansion of CO₂ capture and compression capability at the Shute Creek LaBarge gas plant.