CarbonSAFE Phase I: Integrated CCS Pre-Feasibility – Northwest Gulf of Mexico

Offshore storage achieves two major objectives for the US commercial large scale CCS deployment:

1. Adding large capacity to serve local regional, and potentially broader objectives
2. Lowering risk by providing storage with one public owner, away from population, with no conflict with water resources and reduced concern about induced seismicity.

A high-concentration CO2 source was identified as the top candidate for the project and going forward with the CarbonSAFE Phase II proposal. The top-rated source is the NET Power facility in Houston (La Porte), Texas.

A manuscript based on analysis of results from the two-stage survey conducted in eight selected Texas counties (Brazoria, Chambers, Liberty, Galveston, Jefferson, Orange, Fort Bend and Harris) was submitted to the International Journal of Greenhouse Gas Control on August 21, 2018.

A primary confining interval (seal) is associated with MFS9 (biochronozone Amphistegina B) which can reach a thickness of up to 250 m. However, the Amphistegina B confining interval thins considerably in the onshore direction. Consequently, the most suitable portion of the Miocene section for future CO2 sequestration in the study area is considered to be the offshore area where Amphistegina B is thickest.

Based on three models for capacity assessment, the study proposes a base case for the High Island 10-L Field in which 9 wells operated for 12 years each completed into 4 zones will emplace a total of 150MMT of CO2 with wells placed in the water leg where all the plume will slowly migrate into the structural trap is feasible in terms of geology and engineering.

The 10-L Field was assessed in more detail than other examined oil and gas fields in the study area in order to look at some specifics about how initial future CCS projects might be accomplished in the favorable GoM of the US region and expand the sites to a larger set to experiment with matching all the possible sources to sinks. The 10-L site is large enough to accept CO2 from multiple sinks; the expanded sinks are estimated to be large enough to accept all the CO2 from the region plus some from outside the region.

A number of uncertainties were identified. The largest and most consequential uncertainty is the cost of offshore pipelines in the study setting, which impacts the conditions where CO2 transport would be by ship versus the cases where pipeline would be preferred. Ships are preferred for small volumes and short durations; pipelines for larger volumes and long duration. Additional work is needed to advance the maturity of multiple sinks available, to continue outreach to industries and the public, and to develop realistic source opportunities.

The study demonstrates that industrial source clusters connected to a transport hub delivering CO2 to a nearby storage complex is the most cost-effective and improved way to de-carbonize industrial activities, particularly, in an expected low-carbon and increasing carbon price environmental. The feasibility of the new business models should be based on the best use of the existing infrastructure and strategically build on new supporting infrastructure to drive down the costs of large-scale CCS deployment. Assessing the pre-feasibility of the commercial implementation of a CCS cluster and hub in the GoM energy ecosystem, our study links these elements successfully through an optimized combination (minimum cost) of CO2 sources on land with offshore storage.

Offshore storage achieves two major objectives for the US commercial large scale CCS deployment:

1. Adding large capacity to serve local regional, and potentially broader objectives
2. Lowering risk by providing storage with one public owner, away from population, with no conflict with water resources and reduced concern about induced seismicity.