Water–rock interaction and the concentrations of major, trace, and rare earth elements in hydrocarbon-associated produced waters of the United States

Bern, Carleton R.; Birdwell, Justin E.; Jubb, Aaron M.

doi:10.1039/d1em00080b

Cited by 6 publications

(7 citation statements)

References 87 publications

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“…The SFF that was reacted with only shale showed the greatest increase in sulfate and the lowest Ba concentration. We suggest that oxidative dissolution of pyrite within the shale could be a primary source of sulfate and driver of barite precipitation. , …”

Section: Resultsmentioning

confidence: 89%

“…We suggest that oxidative dissolution of pyrite within the shale could be a primary source of sulfate and driver of barite precipitation. 6,21 The decrease in Ba concentration across the suite of experiments was accompanied by an increase in δ 138 Ba (Figure 2b), with the shale-reacted sample showing the greatest change. These results are consistent with closed-system Rayleigh isotope fractionation of Ba from barite precipitation using published fractionation factors.…”

Section: Resultsmentioning

confidence: 97%

“…23,27,28 While Ba within the Marcellus Shale is primarily partitioned into the lattices of clay minerals, 23,26 a significant portion could be held in even trace amounts of barite. 6,26,29 Sequential extraction experiments have shown that a relatively high fraction of Ba (up to 75%) is held on shale exchange sites (organic matter and surfaces of clay minerals such as illite and smectite). 23,26 Upon interaction with high ionic strength fluids such as recycled produced water used for hydraulic fracturing, exchangeable Ba can be mobilized through exchange reactions with Ca and Na.…”

Section: Introductionmentioning

confidence: 99%

“…Due to its low solubility constant, Ba readily precipitates as barite in the presence of sulfate; therefore, it has relatively low concentrations in seawater (3–21 μg/L). , In contrast, Ba concentrations can be unusually high in some oil and gas-produced waters (water that is pumped out of a well along with hydrocarbons during the production stage). Marcellus Shale unconventional produced waters from hydraulically fractured wells have average Ba concentrations of about 2200 mg/L − with some being as high as 14 000 mg/L; − in contrast, the Utica/Point Pleasant Shale and conventional Appalachian oil/gas wells average ∼1000 mg/L . Barium isotopes for the Marcellus Shale are isotopically heavy, with δ 138 Ba ranging from +0.4 to +1.5‰ …”

Section: Introductionmentioning

confidence: 99%

“…The interaction of hydraulic fracturing fluid with the host shale also has the potential to mobilize exchangeable Ba, sulfates, and other chemical constituents. ,, While Ba within the Marcellus Shale is primarily partitioned into the lattices of clay minerals, , a significant portion could be held in even trace amounts of barite. ,, Sequential extraction experiments have shown that a relatively high fraction of Ba (up to 75%) is held on shale exchange sites (organic matter and surfaces of clay minerals such as illite and smectite). , Upon interaction with high ionic strength fluids such as recycled produced water used for hydraulic fracturing, exchangeable Ba can be mobilized through exchange reactions with Ca and Na. Stewart et al showed that Ba could be easily extracted from shale mineral surfaces, but that this process could not explain the bulk of the dissolved solids in Marcellus-produced water.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Investigation of Barium Sources and Fluid–Rock Interaction in Unconventional Marcellus Shale Wells Using Ba Isotopes

et al. 2022

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Produced waters from unconventional Marcellus Shale gas wells have anomalously high barium (Ba) concentrations and yield some of the isotopically heaviest Ba measured to date. Experiments were conducted to constrain the source of Ba in these fluids and the controls on barite (BaSO4) precipitation and dissolution in oil and gas wells. Experiments simulating the acidizing stage evaluated the solubility of pure barite and drilling mud in 2 M HCl at 80 °C for periods of 2, 6, and 48 h and resulted in <0.01% barite dissolution with no appreciable change in δ138Ba (138Ba/134Ba normalized to NIST standard 3104a). Static autoclave experiments conducted at 66 °C and 20.7 MPa with combinations of ground Marcellus Shale solids and/or barite-bearing drilling mud with synthetic low-Ba fracturing fluid resulted in decreased Ba concentrations in the fluid, with the largest decrease in the shale-only run. Fluid δ138Ba values increased by about 0.5‰ as Ba concentrations decreased, consistent with closed-system Rayleigh fractionation. Flow-through experiments in Marcellus Shale core conducted for 28 days resulted in effluent Ba concentrations an order of magnitude lower than the influent, while sulfate concentrations increased over time. Effluent δ138Ba values increased over the first 12 days and plateaued at about 1‰ higher than the influent. Modeling suggests a combination of the release of labile shale Ba and barite precipitation. This work indicates that the processes of Ba release from fluid–shale interactions and barite precipitation in fractures and the well bore, while capable of producing high δ138Ba fluids, are unlikely to generate fluids with high-Ba concentrations and δ138Ba values like those in Marcellus-produced waters. We find that the release of sulfate from shale pyrite oxidation rapidly catalyzes barite precipitation and that dissolution of drilling mud barite or natural barite in the shale is unlikely to be the major source of Ba in Marcellus-produced waters.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 97%