Brine Chemistry Research Articles

Induced carbonate dissolution: Impact of brine chemistry in CO2 foam

Foam CO2might be considered an efficient alternative to reduce gas mobility and produce favorable mobility ratios. It offers significant advantages, particularly in heterogeneous or fractured reservoirs due to its ability to block highly permeable layers or divert the injected fluid from fractures into the matrix. In the present work, a surfactant solution made of different ionic compositions was co-injected into outcrop Edwards Limestone to determine the impact of brine chemistry on carbonate dissolution upon CO2foam injection. The development in differential pressures (DP) during continuous co-injection of sc-CO2 and different surfactant solutions (NaCl, NFB, CB) shows that unwanted chemical reactions (dissolution/precipitation) compromise the rock integrity by more acid formation and wormholing. Rock-fluid-foam interactions indicate that the total heat in the rock-fluid-foam systems is 6.9 mJ NaClfoam, 19.3 mJ NFBfoam, and 37.8 mJ CBfoam systems. On the other hand, the total heat for the fluid-foam interactions is 11.5 mJ NaClfoam, 12.5 NFBfoam, and 20.4 mJ CBfoam. The demicellization of the foam formulations could have led to calcite dissolution. The synergy between ITC and core flooding experiments elucidates the impact of the brine chemistry on calcite dissolution during foam-assisted CO2sequestration at both microscopic and macroscopic scales.

Experimental Investigation on the Interfacial Characteristics of Tight Oil Rocks Induced by Tuning Brine Chemistry.

Currently, research on enhancing imbibition oil recovery in tight oil reservoirs through the ion-tuning technique remains limited. Two critical parameters for capillary imbibition are the wettability and interfacial tension between oil and water. In this investigation, we manipulate the properties of two types of formation water for both aged and unaged samples by diluting brine and altering ion composition. Subsequently, we employ captive and pendant-drop methods to assess rock wettability and interfacial tension under varied brine conditions. Additionally, we elucidate the primary mechanisms underlying changes in rock wettability and interfacial tension. Meanwhile, we analyze capillarity characteristics and assess the relative significance of wettability and interfacial tension. Results indicate that there is a critical interfacial tension with progressive dilution of two types of formation water. However, modifying ion composition leads to a complex trend in interfacial tension, which can be explained qualitatively through the Gibbs adsorption isotherm. For unaged samples, the contact angle demonstrates a pronounced water-wet characteristic, showing a nonmonotonic trend with respect to dilution times. Remarkably, the rock surface exhibits the strongest water-wet, particularly evident in the case of FW-10, largely influenced by variations in interfacial tension. Conversely, aged samples demonstrate strong oil-wet, with a critical salinity resulting in the lowest contact angle, while altering brine ion types can alter rock wettability from strongly oil-wet to intermediate-wet, which is not sufficient to result in the wettability alteration. The removal of multivalent cations is proposed as the most effective method for wettability modification. Furthermore, capillarity variations among different brine cases are primarily contingent upon contact angle changes, and interfacial tension does not have a significant change when regulating the brine properties. Consequently, we emphasize the significance of wettability in the adoption of ion-tuned brine techniques for tight oil reservoirs. Overall, our study underscores the potential of reasonably regulating brine properties to enhance capillarity and, thereby, improve imbibition oil recovery.

Thermodynamic Predictions of Hydrogen Generation during the Serpentinization of Harzburgite with Seawater-derived Brines

Salty aqueous solutions (brines) occur on Earth and may be prevalent elsewhere. Serpentinization represents a family of geochemical reactions where the hydration of olivine-rich rocks can release aqueous hydrogen, H2(aq), as a byproduct, and hydrogen is a known basal electron donor for terrestrial biology. While the effects of lithological differences on serpentinization products have been thoroughly investigated, effects focusing on compositional differences of the reacting fluid have received less attention. In this contribution, we investigate how the chemistry of seawater-derived brines affects the generation of biologically available hydrogen resulting from the serpentinization of harzburgite. We numerically investigate the serpentinization of ultramafic rocks at equilibrium with an array of brines at different water activities (a proxy for salt concentration in aqueous fluids and a determinant for habitability) derived from seawater evaporation. Because the existing supersaturation of aqueous calcium carbonate, a contributor to dissolved inorganic carbon (DIC) in natural seawater, cannot be captured in equilibrium calculations, we bookend our calculations by enabling and suppressing carbonate minerals when simulating serpentinization. We find that the extent of DIC supersaturation can provide an important control of hydrogen availability. Increased DIC becomes a major sink for hydrogen by producing formate and associated complexes when the reacting fluids are acidic enough to allow for CO2. Indeed, H2(aq) reduces CO2(aq) to formate, leading to a hydrogen deficit. These conclusions provide additional insights into the habitability of brine systems, given their potential for serpentinization across diverse planetary bodies such as on Mars and ocean worlds.

Characterizing Liquid Water in Deep Martian Aquifers: A Seismo‐Electric Approach

AbstractDeep Martian aquifers harboring liquid water could hold vital insights for current and past habitability. We show that with seismo‐electric interface responses (IRs) we can quantitatively characterize subsurface water on Mars. Full‐waveform simulations and sensitivity analyses across diverse Martian aquifer scenarios demonstrate the technique's effectiveness. In contrast to how seismo‐electric signals often appear on Earth, Mars' desiccated surface naturally removes co‐seismic fields and exposes useful IRs that allow us to characterize several aquifer properties. Changing the aquifer depth, thickness, or quantity changes the IR arrival times or shape: aquifer depth is a strong control on evanescent IRs, thickness affects the relative timing of IRs, and increasing the number of aquifers introduces more dipole sources to the waveform. Other factors, such as aquifer saturation, chemistry, and salinity, strongly affect IR amplitude but have minimal or no effect on waveform shape. Notably, for a deep low‐porosity aquifer, the salinity and brine chemistry (perchlorate vs. chloride) are the strongest controls on signal amplitude. Analyzing the effects of epicentral distance shows that radiating and evanescent IRs separate at large source‐receiver offset, allowing analyses of both signals and accurate event distance derivation. From this numerical investigation of the sensitivity of IRs to deep Martian aquifers, we anticipate future analyses of electromagnetic data from the InSight lander or future missions to Mars and other planets.

Is lithium from geothermal brines the sustainable solution for Li-ion batteries?

The rising demand for Li, paramount for energy storage, necessitates expanded supply. As the supply is concentrated in a few countries, this poses supply chain risks for Li-ion battery makers. To diversify suppliers, alternative Li ore deposits such as geothermal brines are being explored. However, Li extraction from geothermal brines is challenging due to the unique chemistry and elevated temperatures. Since Li-extraction from geothermal brines is in its infancy, data availability and quality are still poor, hampering life cycle assessments. Hence, this study provides a parametrized life cycle inventory model of Li carbonate production from geothermal brines. The model accounts for site-specific environmental conditions and technological features. Life cycle impacts at the Salton Sea in the US (1686 cases) and the Upper Rhine Graben in Germany (1982 cases) are quantified. The high case numbers are chosen to mitigate the high uncertainties in input parameters. Specifically, the brine chemistry, adsorption yield, drilling required and energy inputs are varied. Climate change impacts of selected cases vary within 18–59 kg CO2eq/kg Li carbonate at the Salton Sea and within 5.3–46 kg CO2eq/kg Li carbonate at the Upper Rhine Graben, compared to 2.1–11 kg CO2eq/kg Li carbonate in existing ecoinvent data sets. The wide range of potential impacts underscore the necessity of early-stage assessments of the technologies. In case of high drilling demand and use of fossil energy, climate change impacts of Li-ion batteries using Li carbonate from geothermal brines can increase by 30–41 % compared to literature values.

Brine formation in cold desert, shallow groundwater systems: Antarctic Ca-Cl brine chemistry controlled by cation exchange, microclimate, and organic matter

Groundwater in the McMurdo Dry Valleys of Antarctica is commonly enriched in calcium and chloride, in contrast to surface and groundwater in temperate regions, where calcium chemistry is largely controlled by the dissolution of carbonates and sulfates. These Antarctic Ca-Cl brines have extremely low freezing points, which leads to moist soil conditions that persist unfrozen and resist evaporation, even in cold, arid conditions. Several hypotheses exist to explain these unusual excess-calcium solutions, including salt deliquescence and differential salt mobility and cation exchange. Although the cation exchange mechanism was shown to explain the chemistry of pore waters in permafrost cores from several meters depth, it has not been evaluated for near-surface groundwater and wetland features (water tracks) in which excess-calcium pore-water solutions are common. Here, we use soluble salt and exchangeable cation concentrations to determine whether excess calcium is present in water-track brines and if cation exchange could be responsible for calcium enrichment in these cold desert groundwaters. We show that calcium enrichment by cation exchange is not occurring universally across the McMurdo Dry Valleys. Instead, evidence of the present-day formation of Ca-Cl−rich brines by cation exchange is focused in a geographically specific location in Taylor Valley, with hydrological position, microclimate, soil depth, and organic matter influencing the spatial extent of cation exchange reactions. Up-valley sites may be too cold and dry for widespread exchange, and warm and wet coastal sites are interpreted to host sediments whose exchange reactions have already gone to completion. We argue that exchangeable cation ratios can be used as a signature of past freeze-concentration of brines and exchange reactions, and thus could be considered a geochemical proxy for past groundwater presence in planetary permafrost settings. Correlations between water-track organic matter, fine sediment concentration, and cation exchange capacity suggest that water tracks may be sites of enhanced biogeochemical cycling in cold desert soils and serve as a model for predicting how active layers in the Antarctic will participate in biogeochemical cycling during periods of future thaw.

Observations of Decadal-Scale Brine Geochemical Change at the Bonneville Salt Flats

Over the past century, the Bonneville Salt Flats, which lies on the western edge of the Great Salt Lake watershed, has experienced changing environmental conditions and a unique history of land use, including resource extraction and recreation. The perennial halite salt crust has decreased in thickness since at least 1960. An experimental restoration project to return mined solutes began in 1997, but it has not resulted in anticipated salt crust growth. Here, primary observations of the Bonneville Salt Flats surface and subsurface brine chemistry and water levels collected from 2013 to 2023 are reported. Spatial and temporal patterns in chemistry, focused on density and water stable isotopes, are evaluated and compared with observations across seven periods of research spanning from 1925 to 2023. Declining salinity in the areas to the east of extraction ditches and south of Interstate 80 were observed. Brine extracted for potash production decreased in salinity as extraction rates increased. Between the years 1964 and 1997, the salinity of the shallow aquifer brine located beneath and to the east of the crust experienced a decrease. However, following this period, the salinity stabilized and subsequently increased. Salinity recovery was concurrent with declines in brine extraction and the salt restoration project, with the largest decrease in brine extraction being concurrent with the largest recovery in salinity. The specific impact of the restoration project on the brine salinity increase remains unclear. To the west, the shallow aquifer in the area between the Silver Island Mountains and the salt crust has increased in salinity. This increase is accompanied by a decline in groundwater levels, which enables the underground movement of solutes from east to west, following a salinity gradient away from the saline pan. Over the past 25 years, the alluvial-fan aquifer along the Silver Island Mountains has markedly declined, leading to increasingly more saline and isotopically heavier basinal waters to be extracted for industrial use. This change is concurrent with the onset of the salt restoration project, which relies on alluvial-fan aquifer waters. This compilation of changes in groundwater chemistry provides an important resource for stakeholders working to understand and manage this dynamic and ephemeral evaporite system. It also offers an example of decadal-scale change in a highly managed Great Salt Lake watershed saline system.

Desalination brines as a potential vector for CO2 sequestration in the deep sea

Freshwater scarcity, driven by population growth and climate change, is increasingly mitigated by seawater desalination, globally. As an energy-intensive process, desalination is a substantial source of atmospheric CO2. Nevertheless, desalination may hold a potential for ocean-based atmospheric carbon removal. Here we describe, for the first time, the carbonate chemistry of desalination brines near the submerged marine outfalls of a large desalination plant, their unique CO2 buffering capacity, and potential for deep sea carbon sequestration. We show that reverse osmosis acts as a carbon concentration factory and that the high-density brine plumes could create a vector for long-term CO2 removal to the deep sea below the seasonal thermocline. At present desalination capacity, we estimate that Desalination Assisted Carbon Concentration (DACC) and Carbon Dioxide Removal (CDR) could potentially remove 3.8 Mton CO2/year globally, with a negligible contribution to ocean acidification. This mechanism partially mitigates the high carbon print associated with desalination. SynopsisDesalination reject brines pose environmental challenges upon disposal to sea, but due to their unique properties, may become an opportunity for long-term carbon sequestration.

Recovery of Lithium from Oilfield Brines—Current Achievements and Future Perspectives: A Mini Review

In recent years there has been a significant increase in the demand for lithium all over the world. Lithium is widely used primarily in the production of batteries for electric vehicles and portable electronic devices, and in many other industries such as production of aluminum, ceramics, glass, polymers, greases, and pharmaceuticals. In order to maintain the balance between supply and demand for lithium on the global market, it is essential to search for alternative sources of this element. Therefore, efforts are being made to obtain lithium from unconventional sources, an example of which is the recovery of lithium from oilfield brines. This article provides an up-to-date review of the literature in this particular field based on data from different sources (scientific literature databases, patent databases, company websites and industrial online newspapers). The current achievements and future perspectives for the lithium recovery from brines generated during oil and gas extraction were critically reviewed. An emphasis was placed on chemistry of lithium-contained oilfield brines, technologies (both pretreatment and direct lithium extraction) suitable for lithium recovery and industrial results obtained from pilot trials.

Research and Development on Coatings and Paints for Geothermal Environments: A Review

AbstractGeothermal power plants are complex systems, where the interplay between different metallic components transforms the enthalpy of hot brine in the form of electricity or usable heated water. The naturally occurring variety in brine chemistry, linked to the presence of specific key species, and its thermo‐physical properties, leads to the development of different power plant configurations. Key species and power plant configuration in turn determine the extent of damage experienced by each component in the power plant: erosion, corrosion, and/or scaling, often acting combined. Paints and coatings, compared to changing the component alloy, have represented a preferred solution to mitigate these issues due to advantages in terms of costs and repairability. This is reflected in the large number of publications on research and development in this area within the past ≈50 years, with even an increasing trend in the past 10–20 years, indicating the strong interest to develop this clean and sustainable energy source. Therefore, in this work, the first of its kind after 1980, an in‐depth review of all published work on research performed on paints and coatings for geothermal applications, subdivided by the material system, is provided.

Analysis of crude oil effect for CO2 corrosion of carbon steel - A rotating cylinder electrode approach

Crude oils, especially heavy crude oils, are rarely used in multiphase-flow loop experiments because of the experimental difficulties. Variations in the tested fluid viscosity, emulsification processes, water cut (WC), flow velocity and flow patterns, interactions between the crude oil and brine, the difficulty in obtaining metal/environment electrical continuity by covering the metal surface with crude oil, and the difficulty of selecting appropriate instrumentation to monitor the experiment are some of these problems. Studies indicate that crude oil can change the brine chemistry and influence the preferential oil/water metal-surface wettability, which impacts the corrosion process. Based on the assumption that corrosion would only occur when free water is separated from an emulsion, the risks could be reduced by transporting emulsified crude oils. However, as the solubility of water in crude oil is low, free water can be formed at the bottom of horizontal pipelines when the emulsion destabilizes, causing an increase in corrosion processes. In previous author’s studies, carbon-steel flow-induced corrosion (FIC) tests were carried out in a multiphase-flow corrosion loop containing a liquid phase of brine plus light or heavy crude oils (WC 80) with a gaseous phase of CO2. Higher corrosion rates for heavy crude oil were observed, which were not expected. No experimental studies in multiphase-flow corrosion loops using heavy crude oils in CO2-brine solution were found in the literature. In attempting to understand the reason for the higher aggressiveness of the heavy crude oil, rotating cylinder electrode (RCE) tests were performed under the same conditions used in the multiphase-flow loop.

The evolution of solvation symmetry and composition in Zn halide aqueous solutions from dilute to extreme concentrations.

The emergence of cation-anion species, or contact ion pairs, is fundamental to understanding the physical properties of aqueous solutions when moving from the ideal, low-concentration limit to the manifestly non-ideal limits of very high solute concentration or constituent ion activity. We focus here on Zn halide solutions both as a model system and also as an exemplar of the applications spanning from (i) electrical energy storage via the paradigm of water in salt electrolyte (WiSE) to (ii) the physical chemistry of brines in geochemistry to (iii) the long-standing problem of nucleation. Using a combination of experimental and theoretical approaches we quantify the halide coordination number and changing coordination geometry without embedded use of theoretical equilibrium constants. These results and the associated methods, notably including the use of valence-to-core X-ray emission spectroscopy, provide new insights into the Zn halide system and new research directions in the physical chemistry of concentrated electrolytes.

Interaction mechanism of supercritical CO2 with shales and a new quantitative storage capacity evaluation method

Geochemical interactions between shale and supercritical carbon dioxide (scCO2) may dominate CO2 storage in shale gas reservoirs by changing the brine chemistry and rock properties. Understanding the thermodynamic mechanism of scCO2 with shale is particularly essential for CO2 storage, as it provides an innovative strategy to evaluate the potential of shale gas reservoirs. In this study, ReaxFF molecular dynamics (MD) simulations in combination with scCO2−brine−shale experiments were conducted to gain insight into the storage mechanism. A series of laboratory tests and analyses were used to determine variations in physical and chemical properties. The DAM model was employed to calculate the dissolution, adsorption and mineralization capacities of shale samples. The MD trajectory shows that scCO2/H2O molecules rapidly diffuse to mineral surfaces within 1 ps to initiate adsorption and protonation processes. The interlayer cations that are released more slowly from illite (1.1 ns) and Ca-montmorillonite (1.5 ns) structures consume CO2 via mineralization, resulting in carbonate formation during the reaction. However, due to the release of CO32− during calcite decomposition, Ca2+ leaching at 1.6 ns cannot reduce the amount of CO2 molecules. As evidenced by reaction kinetics from MD and experiments, dissolution, adsorption and mineralization prosesses dominate the CO2 storage in shale gas reservoirs, accounting for 10.0–47.6%, 11.0–28.2% and 21.1–73.5%, respectively. The adsorption capacity is associated with space volume, and the mineralized amount is controlled by the illite and mixed-layer illite/smectite contents. Other factors, such as fluid property and space compressibility may also impact the storage capacity, resulting in a maximum adsorption capacity with a depth of around 800 m and an enhanced mineralized capacity with increasing depth. These findings demonstrate that adsorption and mineralization at storage conditions play a key role in CO2 geo-sequestration.

Technology Focus: EOR Operations (November 2022)

Among the different enhanced-oil-recover techniques, waterflooding is still commonly practiced in part because of its economic potential. During the past 2 years, many papers presented at SPE meetings have dealt with different aspects of waterflooding design, optimization, monitoring, and low-salinity applications. Understanding the injected-water preferential paths is a key aspect of waterflood optimization in reservoirs characterized by strong vertical and areal heterogeneities. Devising specific work flows for such applications is important. These can be easy but powerful tools for visualizing the complex dynamic connections between injectors/producers and aquifer influence areas. They can enable improving the business-time decision-making cycle, resulting in increased operational performance and lower waterflood operating costs by consolidating end-to-end optimization work flows in one platform. Using artificial intelligence (AI) and machine-learning (ML) approaches with reduced-physics models can reduce the time required for this task. Also, ML allows for fast screening of waterflood performance at diverse levels (e.g., reservoir, sector, pattern, and well), enabling prompt identification of opportunities for immediate uptake into an opportunity-management process and for evaluation in AI-driven production forecasting or in a reservoir simulator. As part of waterflood optimization, changing the chemistry of the injected water has been under investigation since early 2000. This process has been named differently in different laboratories (e.g., smart water and low-salinity waterflooding, or LoSal). The new studies are related to its field application. It is interesting that new hybrid applications such as low-salinity water with surfactant flooding and carbonated smart water injection are showing up in the literature. As we move forward, it is expected that the waterflooding recovery factor will increase with additional technology advancements. Recommended additional reading at OnePetro: www.onepetro.org SPE 209426 - Impact of Brine Chemistry on Waterflood Oil Recovery: Experimental Evaluation and Recovery Mechanisms by Behdad Aminzadeh, Chevron, et al. SPE 205426 - Pump Up the Volume—Massive Water-Injection Increase Through Open-Water Stimulations by Alistair Roy, BP, et al. SPE 210154 - Middle East Giant Carbonate Field: Integrated Water-Injection-Optimization Work Flow by Stefano Del Fraro, Eni, et al.

Ca2+] and [SO[formula omitted]] in Phanerozoic and terminal Proterozoic seawater from fluid inclusions in halite: The significance of Ca-SO4 crossover points

Chemical analyses of 2,618 (1,640 new and 978 published) fluid inclusions in marine halite were used to define paleoseawater [Ca2+] and [SO2−4] over the past 550 million years (Myr). Three types of fluid inclusion brine chemistries were recognized based on measured [Ca2+] and [SO2−4]: (1) SO4-rich with [SO2−4] ≫ [Ca2+]; (2) Ca-rich with [Ca2+] ≫ [SO2−4]; and (3) Ca-SO4 crossover points with [Ca2+] ≈ [SO2−4]. The SO4-rich and Ca-rich fluid inclusion chemistries oscillated twice in the terminal Proterozoic and Phanerozoic. Transitions between SO4-rich and Ca-rich seas, here called “Ca2+−SO42−crossover points” occurred four times: terminal Proterozoic–Early Cambrian (544–515 Ma), Late Pennsylvanian (309–305 Ma), Triassic–Jurassic boundary (∼200 Ma), and Eocene–Oligocene (36–34 Ma). New fluid inclusion analyses using laser ablation-inductively coupled plasma-mass spectrometry better defined the [Ca2+] and [SO2−4] in seawater at the Late Pennsylvanian and Eocene–Oligocene crossover points and the timing of the Triassic–Jurassic crossover point. Crossover points coincide with shifts in seawater Mg2+/Ca2+ ratios, the mineralogies of marine non-skeletal carbonates and shell building organisms (aragonite vs. calcite) and potash evaporites (MgSO4 vs. KCl types). Phanerozoic and terminal Proterozoic trends in seawater [Ca2+] and [SO2−4] also coincide with supercontinent breakup, dispersal, and assembly cycles, greenhouse–icehouse climates, and modeled atmospheric pCO2. Paleoseawater [Ca2+] and [SO2−4] were calculated from the fluid inclusion data using the assumption that the [Ca2+] × [SO2−4] ranged from 150 to 450 mmolal2, which is 0.5–1.5 times the [Ca2+] = 11 × [SO2−4] = 29 product in modern seawater (319 mmolal2). Two additional end-member scenarios, independent of the [Ca2+] × [SO2−4] = 150–450 mmolal2 assumption, were tested using constraints from fluid inclusion [Ca] and [SO4]: (1) constant [SO2−4] = 29 mmolal as in modern seawater, and variable [Ca2+], and (2) constant [Ca2+] = 11 mmolal as in modern seawater and variable [SO2−4]. Mg2+/Ca2+ ratios calculated from the three scenarios were compared to independent data on the Mg2+/Ca2+ ratios from skeletal carbonates (echinoderms and corals) and mid-ocean ridge flank calcite veins. Constant [Ca2+] of 11 mmolal is unlikely because this relatively low concentration generated unreasonably low seawater [SO2−4] during most of the past 550 Myr and high Mg2+/Ca2+ ratios compared to independent data. Constant [SO2−4] of 29 mmolal produced unreasonably high seawater [Ca2+] and lower Mg2+/Ca2+ ratios than those derived from fluid inclusions, echinoderms, corals, and calcite veins. Variable [Ca2+] and [SO2−4] showed the best agreement with the Mg2+/Ca2+ ratios derived from fluid inclusions, echinoderms, corals, and calcite veins.

Physical, chemical, and microbial feedbacks controlling brine geochemistry and lake morphology in polyextreme salar environments

Despite the harsh environmental conditions in the world's oldest and driest desert, some salt flat or ‘salar’ environments in the Atacama Desert host standing bodies of water known as saline lakes. Evaporite minerals deposited within saline lakes result from the equilibrium of environmental, sedimentological, and biogeochemical processes that occur in the salar; consequently, these minerals are sensitive records of human activities and ecological, evolutionary, and geological changes. The objective of this study was to evaluate feedbacks between physical, chemical, and microbial processes that culminate in distinct trends in brine chemistry, saline lake morphology, and associated evaporite sediments. Using samples from the Puquios of the Salar de Llamara, Atacama Desert, northern Chile, an analysis of spatial gradients and vertical stratification of lake elemental chemistry and mineral saturation indices were integrated with a comprehensive analysis of lake morphology, including depth, slope gradient, substrate type, and mineralogy. Lake waters ranged from saline to hypersaline, and exhibited normal, well mixed and inverse stratification patterns, and results suggest a correlation with lake morphology in the Salar de Llamara. Saline to hypersaline lakes (>150 mS/cm) with stratified brines tended to have crystalline substrate and deep (>35 cm) and steep-sided lake morphologies, while unstratified lakes with lower electrical conductivity (<90 mS/cm and microbial substrates had gentle slopes and characteristically shallow depths (<30 cm). Differences in minor element chemistry (Mn and Sr) between saline lakes were observed on scales of meters to kilometers, and result in different accessory mineral assemblages. Quantification of the physical, chemical, and microbial feedbacks that produce the observed heterogeneity in these ecosystems provides key insight into the geochemical composition and lake morphology of saline lakes in extreme environments around the world.

Impact of polymer on electro-kinetic properties of crude oil, brine and rock interfaces

In recent years, there has been a growing interest in the petroleum industry to improve the ultimate oil recovery method by using low-salinity polymer flooding (LSPF) with the synergistic effect by combining polymer and low-salinity water injection. Although numerous research studies have focused on the technical and economic benefits of low salinity polymer (LSP), to the best of our knowledge, crude oil/brine/rock (COBR) interactions in LSP did not receive enough attention due to the complexity of the interactions between brine, polymer, crude oil, and the rock surface. Therefore, this study aimed to investigate the impact of polymer on COBR interactions with different brine chemistry and improve the understanding of active mechanisms of LSPF. Partially hydrolyzed polyacrylamide (HPAM) polymer, Boise rock, a crude oil sample from an Omani oil field, and several brine solutions were used in the study. Zeta potential and pH measurements were performed to examine the role of polymer on electrical properties of brine/rock and oil/brine interfaces. In addition, rheological properties of the polymer were investigated at different salinity and brine compositions. Changes in Boise rock surface charge through zeta potential measurements were investigated in the absence and presence of polymer. pH and rheology measurements for equilibrated brines with and without polymer and zeta potential of crude oil/equilibrated brine were performed. The results revealed that the addition of polymer to the brine not only increased the viscosity, but also affected the electrical charge at crude oil/brine/rock (COBR) interfaces and triggered pH increase of the brine. The impact of polymer on COBR interactions is mainly controlled by the water chemistry. In the absence of ions, polymer molecules did not affect the charge of COBR interfaces, while in the presence of ions, at different compositions and concentrations, the charge of COBR interfaces changed to become more negative. Thus, the presence of polymer in brine increases the electrostatic repulsion between crude oil/brine and brine/rock interfaces, increases electrical double layer (EDL) thickness, and makes the water film more stable. A direct relationship between the viscosity and zeta potential of the polymer solutions was observed at different brine chemistry. Moreover, the presence of polymer at different brine chemistry resulted in an increase in pH of the aqueous phase. This could in turn reduce the adsorption of polar organic acids from crude oil. Therefore, in addition to the reduction of the water-oil mobility ratio, polymer molecules could contribute to an increase in the repulsion forces between COBR interfaces and an increase in the pH of the aqueous solution.

Physical and chemical properties of sea salt deliquescent brines as a function of temperature and relative humidity

Thermodynamic modeling has been used to predict chemical compositions of brines formed by the deliquescence of sea salt aerosols. Representative brines have been mixed, and physical and chemical properties have been measured over a range of temperatures. Brine properties are discussed in terms of atmospheric corrosion of austenitic stainless steel, using spent nuclear fuel dry storage canisters as an example. After initial loading with spent fuel, during dry storage, the canisters cool over time, leading to increased surface relative humidities and evolving brine chemistries and properties. These parameters affect corrosion kinetics and damage distributions, and may offer important constraints on the expected timing, rate, and long-term impacts of canister corrosion.

Surface analyses of low carbon steel and stainless steel in geothermal synthetic Na-Ca-Cl brine saturated with CO[formula omitted

In a geothermal power plant, certain precautions should be taken to ensure a good efficiency. Indeed, it is important to avoid degassing of the geothermal fluid and to prevent corrosion issues. To address these problems, the gas–liquid equilibrium has to be controlled and the characteristics (composition, temperature…) of the fluid known as well as the nature of the material used.For this reason, in this paper, a laboratory-scale device was developed in order to simulate natural like conditions and achieve corrosion tests. The corrosion behaviour of two materials, a carbon steel (DC01) and a stainless steel (304 L), has been investigated. The testing materials have been exposed to a synthetic brine which composition is similar to the Upper Rhine Graben water formation. The brine was saturated with 2 MPa of CO2 and heated up to 50 °C and 100 °C.Surfaces of tested metals were analysed by spectroscopic (XPS) and microscopic (SEM) methods in order to characterize corrosion products and to get more information onto the corrosion mechanisms process.The use of the laboratory prototype coupled with surface analysis methods allowed to better understand CO2 corrosion in geothermal environment. The role of the brine chemistry and the impact of temperature and CO2 dissolved concentration have been studied in this work. Indeed, different natures of corrosion products regarding the material composition and microstructure have been highlighted. A mixture of CaCO3 and FeCO3 scale is identified on the carbon steel whereas the stainless steel exhibits a mixture of Cr(OH)3 and FeCO 3 on its surface.

A new CSTR method for scale inhibitor evaluation

In various industries, the mineral scale control is critical to ensure productivity, facility integrity, and health and safety. Among different scaling control methods, the scale inhibitor is one of the most commonly used and economic methods. To optimize scale inhibitor applications, it is required to accurately and efficiently evaluate scale inhibitor performances, and determine the required minimum inhibitor concentration (MIC). However, the traditional NACE static bottle tests, dynamic scale loop (DSL) tests, and the batch laser test are limited by their testing conditions, consumable costs, or testing efficiency, especially when minimal inhibitor information is available. This study developed a new brine chemistry inhibitor (BCIn) CSTR (continuous stirring tank reactor) evaluation method to overcome these limitations. In the BCIn CSTR testing, the supersaturated solution with the same SI is pumped into the reactor without the continuous supply of scale inhibitors. As a result, the scale inhibitor concentration is diluted exponentially, which significantly accelerates the crystallization process and generates much sharper and more reproducible end point. More importantly, this study also developed a mechanistic model that correlates the crystallization processes of the BCIn CSTR and batch laser testing. This correlation model makes the BCIn CSTR method and the batch laser testing method equivalent in terms of scale inhibitor performance evaluation. Using this method, the inhibitor performance screening can usually be finished within 20 min with better accuracy and reproducibility (less than6.6% error). Furthermore, the MIC can be accurately determined by as few as one BCIn CSTR test using the correlation model, instead of via multiple lengthy batch laser tests. We believe this BCIn CSTR method can significantly improve the evaluation of scale inhibitor performance and MIC determination.