Occidental Petroleum Corp. injects about 1 billion cubic feet per day of carbon dioxide into oil reservoirs for enhanced oil recovery (EOR), said Daniel Keiser, the company’s manager of commercial development. That CO₂ comes mostly from natural sources, which means they decline over time.

Keiser told the audience at Christianson’s Biofuels Financial Conference in Minneapolis Sept. 28 that other sources like ethanol plants would provide a stable source of CO₂. “We wouldn’t have to continually invest to maintain the same level of CO₂.”  

Occidental is the world leader in EOR. It has 34 projects that use CO₂, mostly in the Permian Basin in Texas, Keiser said. The company has a dense CO₂ pipeline network in place to distribute to all the projects there. “Once the CO₂ gets there, there’s always a need for it,” he said.  

When the CO₂ is delivered to the field, it’s injected into a well. It sweeps across the reservoir and picks up hydrocarbon in the rock, delivering it to the production wells. Some CO₂ stays in the well, some comes out, he said. The portion that comes out is separated from the gas and is reinjected into the reservoir. “The amount of CO₂ that’s delivered to the field to begin with is equal to the amount that gets stored underground,” Keiser said.  

The fermentation process in ethanol plants has a high CO₂ concentration. “That’s a huge advantage for ethanol.” One drawback, however, is that one ethanol plant does not produce enough concentrated CO₂—at about 10 to 15 million cubic feet per day—to make a project worthwhile, he said. That would require about 300 to 500 million cubic feet per day. “You really need a bunch of plants to participate to get the amount we need.”

Occidental supports incentives for ethanol plants to provide CO₂ for enhanced oil recovery, Keiser said. “I think ethanol is a fantastic source. We just need to figure out which plants are able to participate.”