5:15 PM - 7:15 PM
[MGI28-P05] Horoman Mantle Drilling and Carbon Injection (Project Plan)
Keywords:Horoman Peridotite Massif, Mantle Drilling, Carbon Injection, Carbon Cycle, Carbon Mineralization
The high reactivity of dissolved carbon in aqueous fluids with the mantle has been demonstrated in natural occurrences of carbonated peridotites, including ocean fracture zones and ophiolites. This suggests a significant contribution of mantle carbonation as a global carbon sink. However, the global budget of mantle carbonation is still highly uncertain with respect to the alteration mechanism, effective carbonation rates, and how fluid flow changes with time. These questions are extremely difficult to address from natural outcrops and laboratory experiments.
We propose a drilling and carbon injection project in the Horoman peridotite massif to understand the mantle alteration and carbonation process through field experiments. Our primary objectives are to 1) continuously quantify core records of alteration and fracture in the Horoman peridotites compared to those from the Oman Drilling Project, 2) how physical and chemical properties change during CO2 injection and detect mantle carbonation, and 3) direct insights into carbonation rate and fluid flow from the field-scale experiment.
This project consists of two ~100 m deep boreholes: Hole #1 will be the injection hole, and Hole #2 will be the monitoring hole. CO2-rich fluids will be injected from Hole #1, and fluid movement and carbonate mineralization will be monitored from Hole #2. The borehole will be sealed by the packer ring and CO2 fluids will be injected at the depth where the horizontal fracture zone is identified. The CO2-rich acidic fluids can enhance the dissolution of olivine and accelerate the release of divalent cations from the surrounding peridotites. In contrast to the injection fluid, the fluid equilibrated with ultramafic rocks can be characterized by an extremely high pH, and such a large pH gradient in the fluids is likely to precipitate carbonate minerals. We will determine the spatio-temporal distribution of fluid transport and carbon mineralization from changes in seismic velocity, electrical resistivity, and fluid chemistry during the injection period.
We propose a drilling and carbon injection project in the Horoman peridotite massif to understand the mantle alteration and carbonation process through field experiments. Our primary objectives are to 1) continuously quantify core records of alteration and fracture in the Horoman peridotites compared to those from the Oman Drilling Project, 2) how physical and chemical properties change during CO2 injection and detect mantle carbonation, and 3) direct insights into carbonation rate and fluid flow from the field-scale experiment.
This project consists of two ~100 m deep boreholes: Hole #1 will be the injection hole, and Hole #2 will be the monitoring hole. CO2-rich fluids will be injected from Hole #1, and fluid movement and carbonate mineralization will be monitored from Hole #2. The borehole will be sealed by the packer ring and CO2 fluids will be injected at the depth where the horizontal fracture zone is identified. The CO2-rich acidic fluids can enhance the dissolution of olivine and accelerate the release of divalent cations from the surrounding peridotites. In contrast to the injection fluid, the fluid equilibrated with ultramafic rocks can be characterized by an extremely high pH, and such a large pH gradient in the fluids is likely to precipitate carbonate minerals. We will determine the spatio-temporal distribution of fluid transport and carbon mineralization from changes in seismic velocity, electrical resistivity, and fluid chemistry during the injection period.