"Fit-for-Purpose" projects are focused on developing specific subsurface engineering approaches that address research needs critical for advancing CCS to commercial scale. These projects include CO2 injection field tests, as well as applied research and development projects. The field tests augment the information gathered through the Regional Carbon Sequestration Partnerships. The RCSPs have provided valuable data, but complex issues surrounding the processes associated with geologic CO2 storage and monitoring across various types of formations and depositional environments still remain. Research challenges being addressed by current and future applied research are focused on developing specific subsurface engineering approaches to address research needs that are critical for advancing CCS to commercial scale, such as confirmation of modeling results from advanced pressure management with brine extraction.
Map depicting Fit-for-Purpose CO2 injection field test locations.
The table below provides details about each project.
Field test projects are designed to demonstrate that regional storage formations have the capability to store CO2 and provide the foundation for large-volume, commercial-scale projects. They are focused on developing a better understanding of different types of geologic storage reservoir classes to provide insight into how these depositional systems are capable of influencing the fluid flow within them. These storage reservoirs may contain natural gas, oil, and/or saline water–any of which may impact CO2 storage. Read More!
|Tracer injection at the Central Appalachian Basin unconventional CO2 storage test site.
(click to enlarge)
Field project data provides valuable information regarding specific formations that have not yet been evaluated for CO2 storage. The projects focus on the following research objectives:
- Confirm storage resources and injectivity estimates for target reservoirs.
- Validate the effectiveness of simulation models and MVA technologies to predict and measure CO2 movement in the storage formations and confirm the integrity of the seals.
- Develop guidelines for well completion, operations, and abandonment in order to maximize CO2 storage potential and mitigate release.
- Satisfy the regulatory requirements for CCS projects.
- Gather field data to improve estimates for storage capacity that could be used to update regional and national storage resource and capacity estimates.
Understanding the impacts of different depositional systems on flow, injectivity, containment, and capacity are critical to broad deployment of CCS projects throughout the United States. This can only be accomplished by testing and monitoring CO2 in field projects, which help to validate simulation models and determine the effectiveness of the technologies needed to monitor CO2 in the storage formations.
Research and Development Projects
Fit-for-Purpose R&D projects are addressing specific technical issues necessary to advance development CO2 injection and storage field projects. Projects are addressing subsurface engineering issues like plume geo-steering and brine extraction and pressure management will focus on saline formations in all storage formation classes. Projects addressing storage associated with Enhanced Oil Recovery (EOR) will focus on depleted oil reservoirs including utilization of residual oil zones (ROZs). Research that needs to be addressed by current and future Fit-for-Purpose projects includes:
- Reservoir pressure management – In deep saline formations, pressure increases due to injection can potentially increase the risk of induced seismicity, limit injection rates, or result in potential vertical brine migration through leakage pathways. The extraction of brine is a promising approach for mitigating these impacts by reducing increases in reservoir pressure and the areal extent of the pressure increase. It may also be used to provide active plume management.
- Development of storage associated with EOR - Research is being conducted to optimize both oil production and associated CO2 storage in EOR operations. DOE is focusing research on increasing the amount of associated CO2 stored in CO2-EOR operations (1) in non-conventional CO2-EOR targets, including residual oil zones, where CO2-EOR has not been previously applied; and (2) at conventional CO2-EOR targets to enable CO2 storage beyond the level that is normally stored under current practices and in an effort to attaining net carbon negative oil (NCNO). Read More!
Net carbon negative oil can be defined as oil whose CO2 emission to the atmosphere, when burned or otherwise used, is less than the amount of CO2 permanently stored in the reservoir in order to produce the oil. The overall carbon balance of a specific CO2-EOR operation may also have an economic impact if future laws and regulations attach a monetary value to the emission and/or storage of CO2.
Residual oil zones are areas of immobile oil found below the oil-water contact of a reservoir and are similar to reservoirs in the mature stage of "water-flooding" in which water has been injected into a formation to sweep oil toward a production well. In the case of ROZs, the reservoir has essentially been water-flooded by nature and requires EOR techniques, such as CO2 flooding, to produce the residual oil. Research is needed to better understand the potential of ROZs for carbon storage associated with EOR as well as the possibility for NCNO in CO2-EOR operations in ROZs. ROZs (conventional ROZs) are ofton found at the base of oil reservoirs. Some studies have suggested that ROZs (non-conventional ROZs) may also occur beyond the boundaries of existing oil reservoirs, in "fairways." Research is needed to better understand the geographic extent of such deposits and their associated hydrocarbon recovery estimate. Research needs include improved modeling and prediction of storage capacity and efficiency as well asdevelopment of appropriate monitoring techniques to ensure storage permanence.
|Reservoir simulation of injection scenarios are being used to calibrate reservoir models and to identify the scenarios that lead to improvement in CO2 sweep efficiency in tight oil formations. (click to enlarge)