Neutralizing Carbonic Acid in Deep Carbonate Strata Below the North Atlantic
Project # 42123

Primary Performing Organization:
Harvard University

	Schematic drawing of the experimental system.

The potential of this project to provide an economical means of carbon dioxide (CO₂) disposal depends upon the feasibility of long-term CO₂ sequestration in deep-sea calcium carbonate sediments.  If deep-sea injection of neutralized CO₂ works as expected, the CO₂ would react to form bicarbonate ions that would be permanently trapped as a “pore fluid.”  Among the advantages this project would provide is to expand the limited options for disposal of the large volume of CO₂ produced along the densely populated Eastern Seaboard. See schematic of system.

The type of hydrofracturing (injecting water under high pressure) used in deep sea oil extraction indicates that reservoirs created by this process would provide a series of barriers limiting the escape of injected CO₂.  If bicarbonate-rich pore fluid did mix with seawater, then the ocean would provide an additional safeguard.  Effects on the atmosphere, even on the time scale of millennia, are considered to be extremely small, and the process should qualify as a near-permanent sequestration method.

The objectives of the project include:

• To understand the mechanical and chemical behavior of CO₂ and CO₂/water mixtures injected into carbonate sediments of various composition under a range of pressures and temperatures.
• To investigate the kinetics of calcium carbonate dissolution in the presence of CO₂/water.
• To investigate CO₂ hydrate formation in the pore fluid.
• To conduct an economic analysis to estimate costs of drilling, gas injection, and site monitoring.

Contact:
Project Manager: Heino Beckert, heino.beckert@netl.doe.gov

Related Papers and Publications:

• Neutralizing Carbonic Acid Fact Sheet [PDF]