Over the years carbon dioxide (CO2) floods have helped North American producers recover an impressive amount of incremental oil and extend fields' economic lives. Now there may be potential to help even more fields live longer, but the process will take vision and new technology.

In the Permian Basin, 675 million bbl of incremental oil have been brought up on tertiary floods powered by CO2. In Wyoming some 145 million bbl have been recovered, and lesser amounts have been brought up in the other three main CO2-driven fields in Mississippi, Louisiana and Canada.
Since the mid-1990s, Lanny Schoeling, formerly of Shell CO2, now with Kinder Morgan CO2 Co., counts 23 flood startups in older US and Canadian fields. All were supplied with CO2 from natural wells and delivered by pipeline.
Still more properties in and out of the reach of CO2 pipelines are reaching the age where tertiary recoveries could be applied. Schoeling's close look at CO2 flooding in a talk before the April DOE/SPE Odyssey 2000 EOR/IOR conference in Tulsa revealed a complex interplay of factors that could determine the future of CO2 floods.
Technical development is urgent in many fields. Those nearing the end of their economic lives must show improvement soon or be abandoned. Several factors must be considered.
Independents
Most properties that can benefit from CO2 floods are owned by independent oil producers, many of whom are unconvinced of their value. The profit potential needs to be made clear, the risks explained and the vision revealed for them to take action.
Distance
Natural sources of CO2 and pipelines that deliver them are limited. Many properties that could benefit are far from natural sources.
Programs designed to help are under way, Schoeling said.
Shell started the Central Kansas Initiative 2 years ago in partnership with Kansas Independent Oil and Gas Association, Kansas University and the state to evaluate the potential for CO2. The US Department of Energy is funding a test of the Lansing KC Formation, where up to 300 million STB may be recoverable.
California has the largest potential outside the Permian Basin for enhanced oil recovery. Between Bakersfield and the Pacific Coast reservoirs, some 500 million STB should be recoverable. The first of the demonstrations of CO2 effect is slated for Chevron's Lost Hills field in the San Joaquin Basin. If incremental recovery succeeds at Lost Hills, it will focus attention on the need for alternate CO2 sources.
Alternate sources
The cost of pipelines and the likely price of oil means much of the future of CO2 drives may depend on finding new sources of CO2. One area of high interest is extraction of CO2 from flue gases, termed sequestration. Such recovery has an environmental driver as well as the economic one for secondary recovery. Early tests in this area show recoveries with today's technologies could obtain CO2 for between $1.50/Mcf and $2/Mcf. This is well above the costs Permian Basin producers have paid to achieve the incremental rates of return shown. Improvements in sequestering technologies are just beginning to be researched, so potential is high for cost reduction. Other means of sequestration such as adsorption and fuel cell separation are reaching the demonstration stage. And technology being what it is, something completely different may occur to change everything.
CO2 flood has been a big factor in extending the life of the Permian Basin and other North American fields. These lines of research just might bring longer lives to oil fields all over the world.