Systematic Study of Geothermal Brine Reinjection for SaltPower Generation Purposes: Citric Acid as a Potential Iron Control Agent

Cobos, Jacquelin E.; Søgaard, Erik Gydesen

doi:10.1016/j.geothermics.2021.102116

Cited by 10 publications

(26 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both corrosion (e.g., iron flakes) and scaling products could have caused the unforeseen injectivity problems in which the injection pressure was higher than the system design pressure. Cobos and Søgaard [30] observed a 9% permeability reduction on average when Sønderborg brine was injected into Berea sandstone core plugs since the initial permeability to the brine was higher than the measured permeability during the brine injection. These authors mentioned that a discontinuity in the fluid injection creates a higher permeability reduction.…”

Section: Propertiesmentioning

confidence: 95%

“…The characteristics of the Sønderborg geothermal plant taken from Cobos & Søgaard [30] are presented in Table 4. As observed the geothermal fluid has a high concentration of sodium, calcium, magnesium, chloride, and sulfate.…”

Section: Water Chemistrymentioning

confidence: 99%

“…As observed the geothermal fluid has a high concentration of sodium, calcium, magnesium, chloride, and sulfate. This composition could indicate that when the original formation water was exposed to high temperatures, some minerals diffused or precipitated into the aqueous phase [30]. The salinity of the Sønderborg formation water is 96-97 g/L expressed as chloride concentration and the Total Dissolved Solids (TDS) is 157 g/L [2].…”

Section: Water Chemistrymentioning

confidence: 99%

“…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]. Further research on this topic is ongoing.…”

mentioning

confidence: 91%

See 3 more Smart Citations

A Geothermal Plant from a Time-Scale Perspective

2021

View full text Add to dashboard Cite

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.

show abstract

Section: Propertiesmentioning

confidence: 95%

Section: Water Chemistrymentioning

confidence: 99%

Section: Water Chemistrymentioning

confidence: 99%

mentioning

confidence: 91%

See 2 more Smart Citations

A Geothermal Plant from a Time-Scale Perspective

2021

View full text Add to dashboard Cite

show abstract

“…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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Microscopic and macroscopic assessment of carbonate dissolution for geologic $${{\hbox {CO}}_{2}}$$ storage

Cobos,

Folkvord,

Søgaard

et al. 2023

Discov Energy

View full text Add to dashboard Cite

Carbon capture and storage in underground formations might be considered as a relevant technology to curb anthropogenic climate gas emissions. However, carbon dioxide ($${{\hbox {CO}}_{2}}$$ CO 2 ) injection can lead to severe rock-fluid interactions depending on the thermodynamic conditions, rock and fluids composition. The progressive dissolution of $${{\hbox {CO}}_{2}}$$ CO 2 in the formation brine results in mineral dissolution/precipitation processes that may drastically change the properties of the reservoir. This study is an attempt to get a deeper understanding of the dissolution/precipitation processes in a heterogeneous limestone at microscopic and macroscopic levels by a synergy between Isothermal Titration Calorimetry (ITC) and core flooding experiments with in-situ imaging to quantify uneven displacement fronts and understand the influence of reactions on a larger scale. Rock-fluid and fluid-fluid interactions, evaluated by ITC experiments, indicate that the carbonate dissolution is unfavorable with respect to enthalpy change but thermodynamically favorable with respect to entropy change (cations and hydrogen carbonate increase in the brine). Core flooding experiments with in-situ imaging by PET/CT show that complex pore structures cause a variation in the availability and ratio of the reactive fluid throughout the porous medium, hence, non-uniform dissolution was confirmed at core scale. The synergy between microcalorimetry and core flooding provides relevant insights into the dissolution of heterogeneous carbonate rocks at both microscopic and macroscopic scales.

show abstract

Systematic Study of Geothermal Brine Reinjection for SaltPower Generation Purposes: Citric Acid as a Potential Iron Control Agent

Cited by 10 publications

References 19 publications

A Geothermal Plant from a Time-Scale Perspective

A Geothermal Plant from a Time-Scale Perspective

Chelating agents for diluted geothermal brine reinjection

Microscopic and macroscopic assessment of carbonate dissolution for geologic $${{\hbox {CO}}_{2}}$$ storage

Contact Info

Product

Resources

About