CO2 Storage Project: Best Practices for Site Screening
Maturation of ‘Prospective Storage Resources’ requires review a large amount of data and analysis with subsequent increasing details from ‘Site Screening,’ to ‘Site Selection’ and finally ‘Site Characterization’ leading to ‘Qualified sites’ ready for permitting.
The data required at each stage; screening, selection and characterization is broadly divided into four areas;
The purpose of Site Screening is to evaluate regions (called Potential Sub-Regions) within a much larger area of interest, such as the entire sedimentary basin.
I. Geological Data
Four key area of Analysis are required
Storage Formation: must have adequate porosity, permeability, salinity (> 10,000 ppm) and pore pressures.
Depth: Adequate depth of storage (> 800m) to maintain CO2 injection at supercritical state.
Confining Zone: Adequate Cap rack and seal to prevent injected CO2 leakage into underground water sources or escape to atmosphere.
Sufficient Pore Volume: Can accept the planned CO2 injection within acceptable pressures.
Reservoir modeling and detailed reservoir characterization is not required at this stage.
II. Site Data
Four key areas of analysis are required
Protected & Sensitive Areas : This includes Wetlands, Source Water Protection Areas, Protected Areas, Species Protection
Population Centers: Not a reason to reject a site, but need to review permissions for site characterization. Right to pore spaces, access to right of Ways (ROW). Therefore site away from population center is preferable.
Existing Resource Development: Proximity to existing hydrocarbon development will give valuable information storage potential with minimal investment. But each wellborn also poses leakages risk and well bore integrity needs to be examined.
Pipeline Right of Ways (ROW): Must be evaluated at site screening. A new pipeline is capital intensive. Existing CO2 pipeline network must be reviewed for size, capacity and age. IF no pipeline storage site must be close to the emission source.
Site suitability analysis is not required at site screening stage as its a detail attended in Site selection phase.
III. Social Context Data
Two key areas of analysis are required
Demographic Trends: This provides social context across the region. The data is available in US from U.S. Census database. This gives a preliminary understanding of the communities in the sub-region where a project might be located and the socio-economic issues they face
Social Context Data: Data that influence public perception of CO2 storage project. Data and research at this stage should be limited readily accessible resources.
Land Use and Environmental History: Is land Industrial, commercial agricultural? Any history of prior oil & gas development means population is accustomed to seeing drilling operations. Dat can be collected easily from industrial activity databases.
Public outreach assessment is not done at site screening or site selection stage. It's a detailed done at site characterization stage.
IV. Regulatory Data
Regulatory data issues and data analysis is not required at site screening stage. Injectivity assessment and UIC well classes for permitting is done later at site selection and site characterization respectively.
The Site Screening process results in identification of Selected Areas that meet geologic screening, proximity, and social context criteria, as well as suitability for injection based on criteria established during Project Definition. The highest-ranked Selected Areas will be evaluated further during Site Selection.