Scott Frailey | Geology Reports

USGS2020

Methodology for estimating the prospective CO2 storage resource of residual oil zones at the national and regional scale

Residual oil zones (ROZs) are increasingly gaining interest as potential reservoirs for carbon dioxide (CO 2 ) storage. Here, we present a national- and regional-scale methodology for estimating prospective CO 2 storage resources in residual oil zones. This methodology uses a volumetric equation that accounts for CO 2 storage as a free phase in pore space and as a dissolved phase in oil and does not assume any oil production associated with CO 2 storage. Reservoir modeling and the CO 2 -SCREEN tool are used to demonstrate that CO 2 storage in residual oil zones will predominantly take place in the free phase (approximately 92–97%) with some storage as dissolution in oil (approximately 3–8 %). Based on this preliminary demonstration, the CO 2 storage efficiency for ROZs using this national- and regional-scale method ranges from 0.61 to 7.1 %. This range indicates ROZs have a similar efficiency potential for storing CO 2 as deep saline formations (0.51–5.4 %).

International Journal of Greenhouse Gas Control↗

USGS2011

U.S. DOE methodology for the development of geologic storage potential for carbon dioxide at the national and regional scale

A detailed description of the United States Department of Energy (US-DOE) methodology for estimating CO 2 storage potential for oil and gas reservoirs, saline formations, and unmineable coal seams is provided. The oil and gas reservoirs are assessed at the field level, while saline formations and unmineable coal seams are assessed at the basin level. The US-DOE methodology is intended for external users such as the Regional Carbon Sequestration Partnerships (RCSPs), future project developers, and governmental entities to produce high-level CO 2 resource assessments of potential CO 2 storage reservoirs in the United States and Canada at the regional and national scale; however, this methodology is general enough that it could be applied globally. The purpose of the US-DOE CO 2 storage methodology, definitions of storage terms, and a CO 2 storage classification are provided. Methodology for CO 2 storage resource estimate calculation is outlined. The Log Odds Method when applied with Monte Carlo Sampling is presented in detail for estimation of CO 2 storage efficiency needed for CO 2 storage resource estimates at the regional and national scale. CO 2 storage potential reported in the US-DOE's assessment are intended to be distributed online by a geographic information system in NatCarb and made available as hard-copy in the Carbon Sequestration Atlas of the United States and Canada . US-DOE's methodology will be continuously refined, incorporating results of the Development Phase projects conducted by the RCSPs from 2008 to 2018. Estimates will be formally updated every two years in subsequent versions of the Carbon Sequestration Atlas of the United States and Canada .

International Journal of Greenhouse Gas Control↗