Carbon capture technology essential for the $1 billion Petra Nova project—intended to capture about 90% of the CO2 from flue gas at a power plant and boost oil recovery by about 300% for an oil field—could be used at other plants and fields.
“There are a lot more fields than there is carbon, and that’s one of the things that make this a great place to do this,” said NRG Energy CEO and President David Crane. “The West Ranch Field, I’m told, is well suited for this, but there is a whole series of fields in this area of Texas. So as long as we can get a pipeline there and we can separate the carbon, we have plenty of opportunities even beyond the West Ranch Field.”
The main opportunities to use carbon from coal plants for EOR are in the Gulf Coast up through Montana and Wyoming, he said, later adding that NRG has worked to remediate the environmental impact of its coal plants by reducing sulfur oxide, nitrogen oxide and mercury emissions. “At this point, to be frank, carbon is the final frontier and … [the] carbon emission of our coal plants is the single biggest liability we have associated with coal-fired generation. If we can turn that from a liability to an asset, which is what this project does, that is a master stroke.”
Hundreds of people flocked to NRG’s WA Parish plant in Fort Bend County, Texas—at the site of what is expected to be the world’s largest commercial scale post-combustion carbon capture facility and EOR project—for a ceremonial groundbreaking event. The plant retrofitting project includes a 132-km (82-mile) pipeline that will funnel captured CO2 to the Hilcorp Energy-operated West Ranch oil field in Vanderbilt, Texas, where it will be used for EOR. Company officials said the oil production at the field could skyrocket from 500 bbl/d to up to 15,000 bbl/d. JX Nippon Oil & Gas Exploration is a project partner.
Essential to the project is carbon capture technology co-developed by Mitsubishi Heavy Industries and Kansai Electric Power Co. As explained in a video during the Sept. 5 event, flue gas from the power plant is run through a vessel where a solvent captures the CO2. The chemical has a socket that fits CO2 perfectly, thus enabling the two to bind and be pumped into a vessel and heated to release the CO2, which is then segregated into a pure CO2 stream.
From here, the CO2 flows through the pipeline to the oil field. Once injected, the CO2 dissolves into the oil, lowering the oil’s viscosity enough so that as water sweeps though the formation, oil is pushed up and produced. From this point, the water, oil and CO2 are separated in a processing facility. The CO2 is then compressed and reinjected into the reservoir, and the process starts again. EOR using CO2 is not new; however, what is unique is the source of the CO2, said Jill Fisk, asset team leader for the West Ranch oil field, Hilcorp.
The field was selected for the project for a variety of reasons, including its reservoir, rock and oil properties, Fisk said in response to questions from the media. Plus, it’s a longtime producer that has had primary and secondary production from water injection, making it a prime candidate for EOR and CO2 injection.
“As far as our development plans, we are developing injection five-spot patterns in the field,” Fisk continued. “Each pattern consists of one injection well and four producing wells, so we expect to receive response fairly quickly after we start injecting CO2.”
Hilcorp ran a pilot to test the CO2 injection concept by drilling one of those five-spot patterns and received a positive response from the producing wells, she said.
The project would deliver up to 1.6 million tons of CO2 per year to the oil field, where the CO2 would be injected into the 98-A, 41-A, Glasscock and Greta sand units of the Frio Formation about 1,524 m (5,000 ft) to 1,920 m (6,300 ft) below ground, according to the project’s final environmental impact statement (EIS). The project, which also calls for the construction of a central CO2 recycle facility near the EOR area, includes initial plans for about nine injection wells and 16 production wells for EOR operations. However, over the project’s 20-year span, the number of wells could surpass 100.
“Existing wells at the West Ranch oil field would be used (i.e., refurbished or deepened as needed) to the extent practicable for the proposed project,” according to the final EIS. “New injection wells would be drilled if the existing wells cannot be reworked for injection. New wells would be installed on existing well pads to the extent practicable. Injection and production wells would be arranged in overlapping five-spot patterns.”
Each five-spot pattern would consist of one injection well surrounded by four production wells.
“The Gulf Coast is the key,” said Justin Furnace, director of external affairs for Hilcorp. “You have plentiful historic legacy oil fields that are receptive to this type of operation, just not a CO2 source like you have in Permian Basin and some of the other areas. When you put all of this together, I do think EOR will be a big part of that future.”
Other companies, he added, will look at this concept as a prospect.
However, as Crane pointed out, the commercial success of the project will depend significantly on oil prices and the EOR results. He admitted that in the future more uses for carbon will have to be created to bolster the business case, but Petra Nova is an important first step.
Daniel Poneman, deputy secretary for the U.S. Department of Energy—which supported the first 60 megawatts of the total 240-megawatt project with $167 million—said the project is about “demonstrating a technology and executing the technology at a commercial scale in a way that works.
“We know the individual parts already work—we know how to capture the carbon, we know how to compress it, we know how to transport, we know how to put it use,” he said. “What we have to do now is have projects like this demonstrate each step of that process and try to rein the cost out of each one of them, because I can assure you that the companies are going to be using this plant to study the process and how each one of these processes can be made to be more efficient.”
He noted that about 40% of the electricity in the U.S. comes from coal, so it’s imperative to use it safely and remove carbon from the equation. The technology used in the Petra Nova project is critical to making a viable model.
“Coal is a critical part of the energy mix in this country and the world in general,” Crane added. “The best thing we can do to make that continue is to be able to combust coal but keep the carbon out of the atmosphere.”
Contact the author, Velda Addison, at vaddison@hartenergy.com.