Study of geothermal brine reinjection by microcalorimetry and core flooding experiments

Cobos, Jacquelin E.; Søgaard, Erik Gydesen

doi:10.1016/j.geothermics.2020.101863

Cited by 14 publications

(17 citation statements)

References 20 publications

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“…10D*SW gives the highest total endothermic enthalpy change (ΔH) because it is more diluted than AW. A similar trend was observed by Cobos et al 39 These authors found that when a 2 times diluted brine is added to 100% brine, the reaction is highly endothermic and driven by entropy. This effect could be attributed to a disruption of the second and third hydration shells around the single ionic species.…”

Section: Addition Of Crude Oil To Chalk Samples Wetted Withsupporting

confidence: 84%

Impact of Compositional Differences in Chalk and Water Content on Advanced Water Flooding: A Microcalorimetrical Assessment

Cobos

Søgaard

2020

Energy Fuels

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Isothermal titration calorimetry (ITC) was used to determine the binding interaction of advanced seawater (AW), which was produced by nanofiltration (NF) and reverse osmosis (RO) processes, and 10 times diluted seawater (10D*SW) onto different chalk + brine + oil systems. Artificial Valhall brine (VB) was added to different types of chalk, and then crude oil was titrated into those systems. This was done to mimic mineral depositions and compositional differences that could occur in an oil reservoir. Finally, AW or 10D*SW was injected separately into the chalk + VB + oil systems. The results from the ITC experiments indicated that the adhesion energies, related to changes in wetting properties, vary significantly depending on the ionic composition of the injection fluid. Minor differences in enthalpy change were also detected depending on the chalk samples.

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Section: Addition Of Crude Oil To Chalk Samples Wetted Withsupporting

confidence: 84%

Impact of Compositional Differences in Chalk and Water Content on Advanced Water Flooding: A Microcalorimetrical Assessment

Cobos

Søgaard

2020

Energy Fuels

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“…We have already started to investigate how to solve the geothermal brine reinjection problems. In our former work, we showed that the main reason for formation damage was the precipitation of Fe(III) oxides [5]. Thereafter, we demonstrated that citric acid could reduce the problem by complexing with iron and improving the rock properties [30].…”

mentioning

confidence: 94%

“…The geothermal production from the Sønderborg plant started in the spring of 2013 from the sandstones of the Gassum formation (Upper Triassic-Lower Jurassic) at a depth of about 1250 m TVD [4]. The geothermal fluid is extracted with an average temperature of around 48 • C and a salinity of 15% to produce heat which is distributed to the district heating system [5]. This plant was designed to produce up to 12 MW from the geothermal fluid using adsorption heat pumps [1], which are powered by a boiler unit with two woodchip fired boilers.…”

Section: Introductionmentioning

confidence: 99%

A Geothermal Plant from a Time-Scale Perspective

2021

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In recent years, geothermal energy use from low-temperature sandstone reservoirs has sharply increased. Nonetheless, the injection of heat-depleted geothermal fluids has not been an easy task because of well/formation damage and operational/economic issues. Sønderborg geothermal plant is a case example of heat-mining from a low-temperature reservoir. It is in the northeast of Sønderborg towards Augustenborg Fjord. The present work takes into consideration the regional and local geology of the Sønderborg area, construction of the wells, field experience and water chemistry. The main issues of the geothermal plant appear to be related to the construction of the wells and reinjection of the heat-depleted brine. Our water chemistry analysis and PHREEQC simulations indicate that geothermal brine was saturated with respect to carbonate and barite minerals. The excess of Ca2+ and SO42− ions could have led to the formation and precipitation of carbonate and sulfate scales. Moreover, the increment of iron concentration over time could suggest the ingress of oxygen and pitting corrosion due to the presence of halide ions.

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“…Those terms refer to a sustainable energy production based on osmotic gradients resulting from mixing fluids with different salinity (Madsen et al. 2020 ; Cobos and Søgaard 2020 , 2021 ). In the process of “blue energy” production, water molecules are transported spontaneously from the diluted fluid towards the concentrated saltier water due to osmotic forces.…”

Section: Introductionmentioning

confidence: 99%

Chelating agents for diluted geothermal brine reinjection

Cobos

Søgaard

2022

Geotherm Energy

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Abstract“Blue energy” could be produced by exploiting the large salinity gradient between geothermal fluids and freshwater through a SaltPower system. This study is an attempt to select the most favorable chemicals to avoid injectivity issues when a diluted geothermal fluid resulting from the SaltPower system is returned to the reservoir. Three synthetic chelating agents (oxalic acid, EDTA, and EDDS) and one natural (humic acid) were evaluated through speciation simulations and isothermal titration calorimetry (ITC) experiments. The speciation simulation results indicate that the degree of complexing is highly dependent on pH and chelating agent type. The ITC experiments show that the total heat for the formation of soluble metal–ligand complexes in the rock + geothermal brine system follows: EDTA > EDDS > oxalic acid > humic acid. The simulations and calorimetry results suggest that EDTA could be used to avoid the precipitation of Fe(III) oxides and other minerals (e.g., calcite and dolomite) inside the porous media upon the reinjection of diluted geothermal brine coming from SaltPower electricity production.

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Study of geothermal brine reinjection by microcalorimetry and core flooding experiments

Cited by 14 publications

References 20 publications

Impact of Compositional Differences in Chalk and Water Content on Advanced Water Flooding: A Microcalorimetrical Assessment

Impact of Compositional Differences in Chalk and Water Content on Advanced Water Flooding: A Microcalorimetrical Assessment

A Geothermal Plant from a Time-Scale Perspective

Chelating agents for diluted geothermal brine reinjection

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