USGS report outlines method to evaluate underground CO2 storage potential
A new US Geological Survey report describes a probable assessment method developed by the US Department of the Interior division to evaluate underground storage potential for carbon dioxide.
The evaluation, which was authorized under the 2007 Energy Independence and Security Law, uses an approach based on USGS oil and gas resource methodologies created and developed over the last 30 years, USGS said on Mar 16.
It said that the evaluated resource is the volume of subsurface pore space in areas 3,000-13,000 feet deep which can be described within a geologically defined storage assessment unit consisting of a storage formation and an enclosed seal formation.
The report, "Development of a Probabilistic Assessment Method for the Evaluation of Carbon Dioxide Storage," divides storage assessment into physical traps, which are oil and gas reservoirs in most cases, and the surrounding saline formation, which encompasses the rest of the storage formation. The storage resource is determined separately for these two types of storage, its abstract said.
It said that Monte Carlo simulation methods are used to calculate a distribution of the potential storage size for individual physical traps and the surrounding saline formation. To estimate the aggregate storage resource of all physical traps, a second Monte Carlo simulation step is used to sample their size and number, it said.
"The probability of successful storage for individual PTs or the entire SF, defined in this methodology by the likelihood that the amount of CO2 stored will be greater than a prescribed minimum, is based on an estimate of the probability of containment using present-day geologic knowledge," the report's abstract noted.
It said that the report concludes with a brief discussion of needed research data which could be used to refine CO2 sequestration assessment methodologies.
For more information or to order a copy of the report, telephone (888) 275-8747; visit USGS online at http://ask.usgs.gov; contact any USGS Earth Science Information Center, or write USGS Information Services, Box 25286, Denver, Colo. 80225.
Contact Nick Snow at [email protected]