Seeing the Forest for the Trees: Sequestration and Oil Production  

In the past I've occasionally taken a worried look at the possible side effects of carbon sequestration projects, both offshore and onshore. The Energy Blog (always one of the best sources for energy news) has a post up about one onshore project in North America, with the rather misleading title "CO2 Sequestration Project Successful".

Successful Sequestration Project Could Mean More Oil and Less Carbon Dioxide Emissions - Weyburn Project Breaks New Ground in Enhanced Oil Recovery Efforts

Washington, DC – Secretary Samuel Bodman today announced that the Department of Energy (DOE)-funded “Weyburn Project” successfully sequestered five million tons of carbon dioxide (CO2) into the Weyburn Oilfield in Saskatchewan, Canada, while doubling the field’s oil recovery rate. If the methodology used in the Weyburn Project was successfully applied on a worldwide scale, one-third to one-half of CO2 emissions could be eliminated in the next 100 years and billions of barrels of oil could be recovered.

Jim himself is less convinced by the success of the project, making the following notes at the end:

Is this news? Isn't this overstating the importance of this project?

Tthey are admitting that this method of EOR has and is being used in other oil fields. The only thing new is the source of the CO2. Does that make any differance? If this is what it takes to establish injecting CO2 into an oil field for sequestration as demonstrated technology and forms the basis of requiring sequestration in some other situations I guess it has some meaning. Or is this what it takes to convince some that using CO2 for EOR is worthwhile?

Our government has some strange ways of spending our money to justify its actions. This is relatively pure CO2 from a coal gasification plant that is piped over a 100 miles to the oil field. This presumably does not demonstrate sequestration from an industrial source like a conventional coal fired power plant or demonstrate sequestration into a geological formation other than an oil field. So what have we learned? Perhaps in phase II they will get some data as to how much CO2 is staying in the ground which may be of value.

WorldChanging has also taken a less than overwhelmed look at this project and decides its not only not impressive, but is actually worse than not trying to sequester the CO2 at all - "a climate insult dressed up in green clothing".

The US Department of Energy trumpeted the result this week: the DOE-funded “Weyburn Project” successfully sequestered five million tons of carbon dioxide into the Weyburn Oilfield in Saskatchewan, Canada, while doubling the field’s oil recovery rate.

I'm quite certain that you folks have already picked up on the key underlying problem. The additional barrels of oil put out carbon dioxide even while the sequestration buries it. In fact, as I show in the extended entry, the additional oil puts out more CO2 than is buried. The Weyburn sequestration model is a study in the need to pay attention to the trade-offs involved in quick-fix solutions to big problems.

The real carbon dioxide balance isn't spelled out in the press release, of course, but the DOE story gives this helpful bit of information: Scientists project that, by using knowledge gained from the Weyburn Project, the Weyburn Oilfield will remain viable for another 20 years, produce an additional 130 million barrels of oil, and sequester as much as 30 million tons of CO2.

That's the key to the comparison. How much carbon dioxide does 130 million barrels of oil put into the air? A typical barrel of oil produces between 19 and 20 gallons of gasoline; a gallon of gasoline, in turn, produces about 20 pounds of CO2. Each barrel of oil is responsible, on average, for about 400 pounds of carbon dioxide, and that doesn't even begin to count the other uses of the oil in that barrel. It turns out that less than half of a barrel of oil goes to gasoline (19.6 gallons out of 44.4 gallons of total oil products); the majority goes to the production of products like heating fuel oil, jet fuel, lubricants, even some kinds of waxes. Some of those products will also put out a good bit of CO2 into the air.

Five barrels of oil result in a ton of CO2 from gasoline use alone. 130 million additional barrels, therefore, mean at least 26 million more tons of CO2. If the only product from a barrel of oil was gasoline, the balance would just barely be positive. It's not, though, and even if the remaining uses of the barrel were somehow half as "dirty" in carbon dioxide as gasoline, that's still at least another 13-15 million additional tons of CO2, more than eliminating the slight benefit. Using CO2 sequestration for enhanced oil recovery at Weyburn will put about 10 million more tons of CO2 into the air than if we didn't extract the additional oil in the first place. Carbon dioxide sequestration as part of enhanced oil recovery is a climate insult dressed up in green clothing.