Eric H. Oelkers

• BS MIT (Chemistry and Geology) PhD UC Berkeley
• Professor at King Abdullah University of Science and Technology

The ability of Jizan basalts, a potential subsurface mineral carbon storage formation located in southwest Saudi Arabia, to carbonate water-dissolved CO2 has been examined through a set of closed system batch fluid-rock experiments performed at 60 °C. Two Jizan basalt samples were collected from a CO2 injection pilot test well at depths of 375 and...

This study illuminates the mineral carbonation potential of zeolite minerals. Zeolite minerals are common alteration products of basaltic rocks and are known for their ability to rapidly exchange their interstitial cations with those in aqueous solutions. A series of closed system batch reactor experiments was conducted at 60 °C by combining stilbi...

The ability of engineered enhanced rock weathering to impact atmospheric CO 2 has been challenging to demonstrate due to the many processes occurring in soils and the short time span of current projects. Here we report the carbon balance in an Icelandic Histic/Gleyic Andosol that has received large quantities of basaltic dust over 3,300 years, prov...

Anthropogenic carbon emissions have overwhelmed the natural carbon cycle, leading to a dramatic increase in atmospheric CO2 concentration. The rate of this increase may be unprecedented in Earth’s history and is leading to a substantial increase in global temperatures, ocean acidification, sea level rise and potentially human health challenges. In...

The steady-state dissolution rates of basaltic glass and labradorite were measured in the presence of 10 to 700 × 10−3 mol·kg−1 aqueous NaCl, KCl, CaCl2, and MgCl2 at 25 °C. All rates were measured in mixed flow reactors, and at pH~3.6 by the addition of HCl to the reactive fluids. The steady-state basaltic glass dissolution rates, based on Si rele...

The steady-state dissolution rates of basaltic glass and labradorite have been measured in the presence of 10 to 700 x 10-3 mol kgw-1 aqueous NaCl, KCl, CaCl2, and MgCl2 at 25 oC. All rates were measured in mixed flow reactors, and at pH~3.6 by the addition of HCl to the reactive fluids. Steady-state basaltic glass dissolution rates based on Si rel...

Riverine particulates dominate the transport of vital nutrients such as Si, Fe or P to the ocean margins, where they may increase primary production by acting as slow-release fertilizer. Furthermore, the supply of particulate surface area to the ocean is considered to be a major control of organic carbon burial. Taken together, these observations s...

The coastal region of southwest Saudi Arabia contains a thick sequence of Late Oligocene basalts in the Jizan Group, which accumulated along the continental rift that preceded the opening of the Red Sea. These basalts are targeted for the disposal of CO2 emitted from industrial sources by subsurface carbon mineralization processes. The disposal pot...

Massive quantities of carbon dioxide (CO2) need to be captured and stored to achieve net zero CO2 emissons by mid-century and avoid the worst consequences of unchecked global warming. Geologic storage of CO2 may be the only realistic option available to store the bulk of this CO2 due to the required storage volumes. Geologic storage involves the in...

Carbon capture and storage projects need to be greatly accelerated to attenuate the rate and degree of global warming. Due to the large volume of carbon that will need to be stored, it is likely that the bulk of this storage will be in the subsurface via geologic storage. To be effective, subsurface carbon storage needs to limit the potential for C...

The Jizan region of southwest Saudi Arabia contains large industrial point sources of CO2 and potentially the capacity to dispose substantial quantities of this gas by the subsurface mineralization of local basaltic rocks. Significant volumes of basaltic magma were erupted within an Oligo-Miocene continental rift valley that preceded the formation...

Carbon capture and storage projects need to be greatly accelerated to attenuate the rate and degree of global warming. Due to the large volume of carbon that will need to be stored to address this issue, it is likely that the bulk of this storage will be in the subsurface via geologic storage. To be effective, subsurface carbon storage needs to lim...

Magnesium (Mg) is a major element in seawater, rock-forming minerals, and biological systems. Stable Mg isotopes fractionate during silicate weathering and carbonate mineralization, and hence are a promising tool to trace these processes. Magnesium can be present in natural aqueous solutions as a number of distinct inorganic and organic complexes i...

The isotopic composition of carbonate minerals provides a record of historical geochemical and environmental conditions, but the ability to interpret these compositions as paleo-proxies hinges on their preservation over thousand to million year timescales. At chemical equilibrium, alteration of initial isotopic compositions of calcite can occur in...

The injection of water dissolved CO2 and H2S into basalts into the Nesjavellir geothermal system (Iceland) is to begin in 2022. This study is a pre-injection investigation assessing the likely response of the fluid-rock system to the gas charged water injection. The target aquifer has a temperature of < 200 °C at the injection well, but the tempera...

Mineral dissolution rates control the temporal evolution of many natural processes on the surface and upper crust of the Earth. This is the first of a series of papers describing the development and implementation of a comprehensive and internally consistent database of the dissolution rates of the major rock-forming minerals. In this paper, we des...

The Jizan region of southwest Saudi Arabia contains large industrial point sources of CO2 and potentially the capacity to dispose substantial quantities of this gas by the subsurface mineralization of local basaltic rocks. Monte Carlo estimates suggest that the total CO2 mineralization capacity of the mafic igneous rocks in the Jizan area is ~4.2 G...

The potential of geological storage of CO2 by mineralization Since the mid-2000s, researchers have been actively working on carbon storage through mineralization with a major milestone reached in 2016 with the results of the European CarbFix project in Iceland. Since then, this technology has been deployed at an industrial level on the Hellisheiði...

Clay mineral growth can directly affect the chemistry and permeability of many natural systems, including soils, marine sediments, Earth surface waters, geothermal powerplants and carbon dioxide storage sites. Notably, the sluggish precipitation of clay minerals has been hypothesised to hinder Earth surface weathering rates. To date, there are limi...

Quantifying the link between cyanobacterial activity and the carbon isotope signature of precipitated carbonate minerals is crucial for reconstructing the environmental conditions present at the time of carbonate mineral formation. In this study, calcite was precipitated in the presence and absence of Synechococcus sp. cyanobacteria in batch reacto...

Mineralization of freshwater-dissolved gases, such as CO2 and H2S, in subsurface mafic rocks is a successful permanent gas storage strategy. To apply this approach globally, the composition of locally available water must be considered. In this study, reaction path models were run to estimate the rate and extent of gas mineralization reactions duri...

Many abandoned mine sites in Cornwall, UK, are characterised by elevated concentrations of arsenic (As), which can cause contamination of surrounding soil and water resources. These sites have important historical value that requires access to be maintained, despite exposure of humans to toxins that may lead to health issues including hyperpigmenta...

Over millions of years, the interaction of marine basalt with percolating seawater in low-temperature ocean floor hydrothermal systems leads to the formation of calcite and aragonite. The presence of these minerals in marine basalts provides evidence for substantial CO2 fixation in these rocks. Here, we report on laboratory experiments to study thi...

The Husmuli zone of the SW-Iceland Hellisheidi geothermal field is currently being used for re-injection of geothermal fluids and geothermal CO2 for its permanent storage in the form of carbonate minerals. A fully coupled hydro-thermo-mechanical numerical model was employed to investigate the coupled impacts of these complex processes on the calibr...

The fractionation of Ni isotopes during Ni coprecipitation with calcite was measured at pH = 6.2 and pCO2 = 1 atm as a function of calcite growth rate. Light Ni isotopes are preferentially incorporated into calcite during its coprecipitation, which is likely due to a longer Ni-O bond length in calcite compared to that of the Ni aquo complex. The ex...

The mechanisms of siderite (FeCO3) nucleation from aqueous solution depend on the fluid saturation state. In this study we investigate the effect of aqueous fluid saturation on the nucleation pathway of siderite. Thereof, we performed a series of turbidity and batch experiments. Turbidity measurements indicate that at low saturation indices (SI < 3...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Efforts to maintain and enhance reservoir permeability in geothermal systems can contribute to sourcing more sustainable energy, and hence to lowering CO2 emissions. The evolution of permeability in geothermal reservoirs is strongly affected by interactions between the host rock and the fluids flowing through the rock's permeable pathways. Precipit...

The fractionation of carbon and magnesium isotopes is a potentially useful tracer of natural weathering in ultramafic catchments and engineered CO2 storage. To evaluate the use of carbon and magnesium isotopes as tracers of ultramafic weathering and CO2 storage, we assessed the carbon and magnesium isotope fractionation between hydrous Mg-carbonate...

The dissolution rates of Green Monster Mine epidote at temperatures of 25, 100 and 200 °C, and over the pH range 2-11, were determined from far-from equilibrium experiments performed in both batch and mixed-flow reactors. Epidote dissolution rates based on silicon release decrease with increasing pH to pH ∼8, then increase in response to further pH...

Lead(II) is a toxic pollutant often found in metal-contaminated soils and wastewaters. In acidic aqueous environments, Pb(II) is highly mobile. Chemical treatment strategies of such systems therefore often include neutralization agents and metal sorbents. Since metal solubility and the retention potential of sorbents depend on the redox state of th...

Carbon dioxide injection in shale reservoirs can be beneficial for enhanced oil recovery and CO2 storage scenarios. CO2 mass transfer can be influenced strongly by the in-situ liberation of light oil components from live oil forming a distinct gas phase. This mechanism has been overlooked in the past for studying CO2 and oil interactions in tight f...

The geochemistry and petrology of the LDX-1 structure of the Yinggehai basin, a natural analog of a sedimentary carbon storage site, was investigated to understand the consequences of the charging of CO2 gas in this system. The rocks in this structure are dominated by subarkose and sublitharenite sandstones. The authigenic minerals formed after CO2...

The CarbFix method was upscaled at the Hellisheiði geothermal power plant to inject and mineralize the plant’s CO2 and H2S emissions in June 2014. This approach first captures the gases by their dissolution in water, and the resulting gas-charged water is injected into subsurface basalts. The dissolved CO2 and H2S then react with the basaltic rocks...

Abstract. Although the PROFILE and ForSAFE model can accurately reproduce the chemical and mineralogical evolution of the soil unsaturated zone, it overestimates weathering rates in deeper soil layers and in groundwater systems. This overestimation has been corrected by improving the kinetic expression describing mineral dissolution by adding or up...

The fractionation of Ni isotopes during Ni adsorption from aqueous fluids onto calcite surfaces was measured at 25 °C and as a function of pH from 7.7 to 8.9. Experiments showed that the percent Ni adsorbed and the degree of Ni isotope fractionation attained constant values in less than 30 hours after the calcite was exposed to the Ni bearing, calc...

Carbon capture and storage (CCS) has a fundamental role in achieving the goals of the Paris Agreement to limit anthropogenic warming to 1.5–2 °C. Most ongoing CCS projects inject CO2 into sedimentary basins and require an impermeable cap rock to prevent the CO2 from migrating to the surface. Alternatively, captured carbon can be stored through inje...

Fluid-rock interactions in hydrothermal systems at or near mid-oceanic ridges (MOR) play a major role in determining the composition of the oceanic crust and seawater. To quantify the processes that govern cation exchange in these environments we have experimentally studied the isotopic evolution of δ26/24Mg in the fluid phase during seawater-basal...

The steady-state dissolution rates of sepiolite were measured as a function of pH from mixed-flow reactor experiments at 25 °C in both citrate bearing and citrate-free aqueous solutions. Dissolution at pH ≤ 5.5 and pH ≥ 9.18 was found to be non-stoichiometric, with relatively more Mg being released at low pH, while Si was preferentially released at...

Coupled gypsum dissolution-calcium carbonate precipitation experiments were performed in closed system reactors and in the presence of either aqueous 0.1 M Na2CO3, 0.1 M NaHCO3 or 0.1 M Na2CO3 + 0.2 M NaOH solutions. Gypsum dissolved immediately at the start of each experiment provoking the precipitation sequentially of vaterite, calcite and trace...

During the past decade, enhanced oil recovery (EOR) by CO2 in shale oils has received substantial attention. In shale oil reservoirs, CO2 diffusion into the resident oil has been considered as the dominant interaction between the CO2 in fractures and the oil in the matrices. CO2 diffusion will lead to oil swelling and improvement in oil viscosity....

Particulate material plays a major role in the transport of sparingly soluble nutrients such as P and Fe in natural surface waters. Microbes might gain access to these nutrients either indirectly through particulate dissolution or directly through microbial attack. As such, it seems reasonable to expect a link between the particulate material conce...

During carbonated water injection and CO2-WAG scenarios for enhanced oil recovery, dynamic transfer of CO2 from aqueous phase into resident oil can cause complex pH variations, which can affect mineral dissolution around wellbore and precipitation in reservoir. Also, transfer of CO2 from carbonated water into live oil can liberate light components...

The engineered removal of atmospheric CO2 is now considered a key component of mitigating climate warming below 1.5 °C. Mineral carbonation is a potential negative emissions technique that, in the case of Iceland’s CarbFix experiment, precipitates dissolved CO2 as carbonate minerals in basaltic groundwater settings. Here we use calcium (Ca) isotope...

During the past decade, enhanced oil recovery (EOR) by CO2 in shale oils has received substantial attention. In shale oil reservoirs, CO2 diffusion into the resident oil has been considered to be the dominant interaction between the CO2 in fractures and the oil in the matrices. CO2 diffusion will lead to oil swelling and improvement in oil viscosit...

The accurate interpretation of Si isotope signatures in natural systems requires knowledge of the equilibrium isotope fractionation between Si-bearing solids and the dominant Si-bearing aqueous species. Aqueous silicon speciation is dominated by silicic acid (H 4 SiO 4o ) in most natural aqueous fluids at pH < 8.5, but forms H 3 SiO 4⁻ , H 2 SiO 4²...

Silicate weathering is the primary control of atmospheric CO2 concentrations on multiple timescales. However, tracing this process has proven difficult. Lithium isotopes are a promising tracer of silicate weathering. This study has reacted basalt sand with natural river water for ~9 months in closed experiments, in order to examine the behaviour of...

The PROFILE model, now incorporated in the ForSAFE model can accurately reproduce the chemical and mineralogical evolution of the soil unsaturated zone. However, in deeper soil layers and in groundwater systems, it appears to overestimate weathering rates. This overestimation has been corrected by improving the kinetic expression describing mineral...

This study provides direct experimental evidence of the resetting of the calcium (Ca) isotope signatures of calcite in the presence of an aqueous fluid during its congruent dissolution, precipitation, and at equilibrium at ambient temperatures over week-long timescales. Batch reactor experiments were performed at 25 °C in aqueous NaCl solutions; ai...

One of the main challenges of worldwide carbon capture and storage (CCS) efforts is its cost. As much as 90% of this cost stems from the capture of pure or nearly pure CO2 from exhaust streams. This cost can be lowered by capturing gas mixtures rather than pure CO2. Here we present a novel integrated carbon capture and storage technology, installed...