Brine Composition Research Articles

Convective Dissolution of Carbon Dioxide in Deep Saline Aquifers: Insights from Engineering a High-Pressure Porous Visual Cell

We present the first experiments of dissolution-driven convection of carbon dioxide (CO$_2$) in a confined brine-saturated porous medium at high pressures. We designed a novel Hele-Shaw cell that allows for both visual and quantitative analyses, and address the effects of free-phase CO$_2$ and brine composition on convective dissolution. The visual examination of the gas volume combined with the measurement of pressure, which both evolve with dissolution, enable us to yield insights into the dynamics of convection in conditions that more closely reflect the geologic conditions. We find and analyze different dissolution events, including diffusive, early and late convection, and shut-down regimes. Our experiments reveal that in intermediate regime, a so-called `quasi-steady' state actually never happens. Dissolution flux continuously decreases in this regime, which is due to a negative feedback loop: the rapid reduction of pressure following convective dissolution, in turn, decreases the solubility of CO$_2$ at the gas-brine interface and thus the instability strength. We introduce a new scaling factor that not only compensates the flux reduction but also the nonlinearities that arise from different salt types. We present robust scaling relations for the compensated flux and for the transition times between consecutive regimes in systems with NaCl (Ra $\sim$ 3271--4841) and NaCl+CaCl$_2$ mixtures (Ra $\sim$ 2919--4283). We also find that NaCl+CaCl$_2$ mixtures enjoy a longer intermediate period before the shut-down of dissolution, but with a lower dissolution flux, as compared to NaCl brines...

Thermodynamic evidence of giant salt deposit formation by serpentinization: an alternative mechanism to solar evaporation

The evaporation of seawater in arid climates is currently the main accepted driving mechanism for the formation of ancient and recent salt deposits in shallow basins. However, the deposition of huge amounts of marine salts, including the formation of tens of metres of highly soluble types (tachyhydrite and bischofite) during the Aptian in the South Atlantic and during the Messinian Salinity Crisis, are inconsistent with the wet and warm palaeoclimate conditions reconstructed for these periods. Recently, a debate has been developed that opposes the classic model of evaporite deposition and argues for the generation of salt by serpentinization. The products of the latter process can be called “dehydratites”. The associated geochemical processes involve the consumption of massive amounts of pure water, leading to the production of concentrated brines. Here, we investigate thermodynamic calculations that account for high salinities and the production of soluble salts and MgCl2-rich brines through sub-seafloor serpentinization processes. Our results indicate that salt and brine formation occurs during serpentinization and that the brine composition and salt assemblages are dependent on the temperature and CO2 partial pressure. Our findings help explain the presence and sustainability of highly soluble salts that appear inconsistent with reconstructed climatic conditions and demonstrate that the presence of highly soluble salts probably has implications for global tectonics and palaeoclimate reconstructions.

Characterising brines in deep Mesozoic sandstone reservoirs, Denmark

The Danish subsurface contains several sandstone units, which represent a large geothermal resource (Vosgerau et al. 2016). Currently, only three geothermal plants are operating in Denmark, but several exploration licences are expected to be awarded in 2019. Geothermal energy is exploited from deeply buried porous sandstones by bringing warm form­ation water (brine) to the surface, extracting the heat and returning the cooled water to the same sandstones. The reduced temperature of the brine during this process implies a risk of scaling, which may reduce reservoir permeability and hence injectivity. Predicting the chemical composition of formation waters, however, could help to reduce the risk associated with scaling in planned geothermal facilities.
 Here, we present a regional overview of the geochem­istry of brines from deep Mesozoic sandstones in the Danish Basin and North German Basin that supplements previous studies, notably by Laier (2002, 2008). The brine composition at shallow burial typically reflects the original (connate) formation water chemistry, which is determined by the original depositional environment of the sandstone, for example fluvial or marine. However, the mineralogical composition of the sandstone changes during burial, whereby some minerals may dissolve or precipitate when exposed to higher temperatures. These mineral changes are reflected in the brine composition, which typically becomes more saline with increased burial (e.g. Laier 2008; Kharaka & Hanor 2003). 
 The brine chemistry reported here shows a distinct depth trend, which reflects original connate formation waters that are modified through burial diagenesis. We have classified the brines into brine types, which are shown to be related to their depositional environment, depth, geological formation and geographical domains.

A Synergy between Controlled Salinity Brine and Biosurfactant Flooding for Improved Oil Recovery: An Experimental Investigation Based on Zeta Potential and Interfacial Tension Measurements

In this study, we have investigated the effects of brine and biosurfactant compositions on crude-oil-rock-brine interactions, interfacial tension, zeta potential, and oil recovery. The results of this study show that reduced brine salinity does not cause significant change in IFT. However, addition of biosurfactants to both high and low salinity brines resulted in IFT reduction. Also, experimental results suggest that the zeta potential of high salinity formation brine-rock interface is positive, but oil-brine interface was found to be negatively charged for all solutions used in the study. When controlled salinity brine (CSB) with low salinity and CSB with biosurfactants were injected, both the oil-brine and rock-brine interfaces become negatively charged resulting in increased water-wetness and, hence, improved oil recovery. Addition of biosurfactants to CSB further increased electric double layer expansion which invariably resulted in increased electrostatic repulsion between rock-brine and oil-brine interfaces, but the corresponding incremental oil recovery was small compared with injection of low salinity brine alone. Moreover, we found that the effective zeta potential of crude oil-brine-rock systems is correlated with IFT. The results of this study are relevant to enhanced oil recovery in which controlled salinity waterflooding can be combined with injection of biosurfactants to improve oil recovery.

Braskem offers bio-based polymers to promote the circular economy

Using the method of isothermal dissolution equilibrium, stable phase equilibria of unreported strontium-containing systems LiCl–NaCl–SrCl2–H2O and LiCl–KCl–SrCl2–H2O at 298 K have been studied in accordance with the compositions of the underground brine in western Sichuan Basin. The experimental results show that there are no solid solution and complex salt in two quaternary systems. The phase diagram of quaternary system LiCl–NaCl–SrCl2–H2O consists of two invariant points, five isothermal dissolution curves and four crystallization regions. The quaternary system LiCl–KCl–SrCl2–H2O belongs to a simple type and the phase diagram consists of two invariant points, five isothermal dissolution curves and four crystallization regions. The solubilities of salts in the above systems were accurately calculated with Pitzer electrolyte solution theory. It was found that the calculated phase diagrams coincided basically with the experimental phase diagrams by evaluated the accuracy through the experimental results. Meanwhile, the applicability of Pitzer parameters selected in this paper was validated.

Investigation of the effects of ions on short-range non-DLVO forces at the calcite/brine interface and implications for low salinity oil-recovery processes

A primary question investigated in this study is the influence of brine chemistry on the behavior of short-range non-DLVO (e.g., hydration, discrete ion charge effects, and so on) forces at calcite surfaces. Specifically, how do wetting films containing Na+ differ from those containing Mg2+? Force-distance spectroscopy as measured by atomic force microscopy is used to probe short-range non-DLVO forces in various single-salt and multiple-salt electrolyte solutions. Experimental results reveal that, in single-component solutions, a greater concentration of Na+ ions decreases the decay length of short-range repulsion while a greater concentration of Mg2+ ions increases decay length. These results imply that Na+ ions reduce the affinity of calcite surfaces for water whereas Mg2+ ions make calcite more hydrophilic. Importantly, the relationship between the behavior of non-DLVO forces at small separations and concentrations of ions is not monotonic in multiple-component brines. Our observations support the hypothesis that Na+ ions disturb the interfacial water structure of calcite while Mg2+ ions are arranged farther away from the surface. Results obtained here may have implications for the design of so-called low salinity waterfloods where the composition of brines used for crude oil recovery is manipulated to increase oil recovery.

Effect of SO4−2 ion exchanges and initial water saturation on low salinity water flooding (LSWF) in the dolomite reservoir rocks

The low salinity water injection has become one of the most important studies in the oil industry for improving oil recovery compared to conventional seawater injection. Thus, extensive studies have been conducted in carbonate and sandstone reservoirs to investigate how the physical properties of rocks and the chemical composition of fluids influence low salinity effect, while, the carbonate reservoir rocks requires more investigation of the effect of molecular and/or ionic interactions. In this experimental work, the effectiveness of various water flooding schemes in carbonate reservoir rock samples is investigated. In this regard, the oil recovery potential of seawater (SW), reservoir formation water (RFW) and managed water salinity (MWS), with different ion compositions adjusted based on the formation water composition are used. The experiments have been performed on the dolomite core samples and crude oil from an Iranian oil reservoir. Various measurements including zeta potential, XRD, contact angle and interfacial tension have been planned. The main contribution is to investigate the effect of both brine’s ionic composition and rock’s initial water saturation on wettability change and oil recovery. The results show that, the concentration of ion in the injected water must be managed over an optimum range for each case. This results in changing the wettability of carbonate rock to a less oil-wetting state by altering the brine composition and reducing the salinity. Moreover, initial water saturation plays a role in the process, so that, by increasing content in optimum range, the oil recovery increased.

Utilization of Brine Sludge in Controlled Low Strength Materials (CLSM)

Controlled low-strength materials (CLSM) have begun to apply in a lot of countries because CLSM could distribute randomly in complex sites. Manufacturing from chlor-alkali industry, the brine sludge was used to replace the composition in CLSM for resource application. In this study, the mix composition of brine sludge replaced only the fine aggregates or all of the aggregates. Examining the suitable composition, the ball drop test and the compressive strength test were carried out. The ball drop test was applied to determine the readiness of the CLSM to accept loads prior, and the bearing capacity at different ages were measured by the compressive strength test. The results of the ball drop test in different replacements was 7 - 11.5 cm. The replacement of fine aggregates satisified the rule of CLSM. Replacing all of the aggregates, the mixtures were over 7.6 cm, which meant that the early strength at 1 day were not sufficient. The value of compressive strength at 28 days was 1.709 - 21.37 kgf/cm2, conforming the requirement of CLSM. Overall, the mixture which replaced the fine aggregates met all the specified values of CLSM. In particular, the composition of coarse aggregates reduce to 250 kg/m3, the utalization of the brine sludge could be the most.

Role of Brine Composition and Water-Soluble Components of Crude Oil on the Wettability Alteration of a Carbonate Surface

In this study, the effects of amphiphilic water-soluble components of crude oil and ionic composition of water were investigated on the wettability alteration of a carbonate surface. Four different types of saltwater, which are made up of NaCl, MgCl2, CaCl2, and Na2SO4, with 0.5 M ionic strength, besides distilled water, were contacted with crude oil to be saturated with water-soluble components. The post-contact (after contact with crude oil) water properties were characterized by Fourier transform infrared spectroscopy, total organic carbon, and pH analyses. The results showed that some polar compounds of crude oil with basic and mostly acidic functional groups were transferred to saltwater and distilled water. Afterward, the oil-wet carbonate surface was soaked in both freshwater (not contacted with crude oil) and post-contact water, and their effects on the wettability of the surface were investigated through contact angle and scanning electron microscopy experiments. The results of the contact angle ...

Evaporitic carbonates in the pre-salt of Santos Basin – Genesis and tectonic implications

Abstract Since the first discoveries of oil accumulations in the carbonate reservoirs of the Lower Cretaceous Barra Velha Formation of the Santos Basin, their genesis has been the subject of intense discussion. Different depositional models have been proposed, with some authors advocating a microbial origin, while others an abiotic origin as travertines or travertine-like rocks. This search for a modern carbonate analogue for these unusual rocks may have disregarded an intriguing alternative: an evaporative model supported by our petrographical and geochemical data. Evaporitic sediment patterns in endorheic basins, in a depositional framework of brine drawdown, are dominated by ephemeral salt pan hydrology. Bedded salt crusts form a stack of subaqueous aligned crystal beds at the sediment-water interface; salt grows diagenetically within saline and mud layers beneath the dry pan surface; finally laminated sediments are deposited. We observe a similar cyclic pattern in the pre-salt core we described: beds of shrub-like crystals and diagenetic spherulites growing in magnesium clay matrix are followed by laminites. The model we propose attempts to contribute solving the puzzle of Pre-Salt carbonate deposition by integrating sedimentology and geochemistry with basin tectonics. Our observations and basin tectonics point to the exciting possibility that the sag phase carbonates of the Santos-Campos basin were deposited as the initial/transitional stage of a closed sub-sea-level evaporite basin whose rising salinities culminated in the deposition of halite and bittern salts (carnallite, sylvite, tachyhydrite). Basinwide evaporites are singular events in the geological record. They form when a giant sub-sea-level basin becomes a sump of continental, marine and hydrothermal fluids, producing unexpected brine compositions in unusual depositional settings present in ancient evaporitic basins but absent from most modern ones. The novelty in this paper is that we apply to pre-salt carbonate deposition the sedimentology, hydrology and geochemistry of ancient evaporitic basins. With this concept in mind, we propose a geochemical model for the unusual pre-salt carbonate precipitation of the Santos Basin. Regarding the Walvis-Rio Grande volcanic high as a topographic barrier during the Aptian, we suggest that the main sources of calcium to the Barra Velha paleolake were hydrothermal brines, mostly from infiltrating seawater that reacted at depth with the basalts of the volcanic barrier. Hyperextension of the lithosphere, with a shallow Moho, increased geothermal gradients to levels favorable for the generation of hydrothermal CaCl2 brines, a process facilitated by the already elevated Ca++ ion and low sulfate concentration of the Cretaceous ocean. These CaCl2-rich fluids would pass through the volcanic barrier into a sub-sea-level paleolake in the rift basin. The high salinity paleolake would become saturated in calcium bicarbonate/carbonate as internally drained NaHCO3-bearing alkaline waters, formed by physical/chemical weathering of penecontemporaneous basaltic rocks, mix with the CaCl2-bearing hot brines percolating through the barrier, producing a hybrid brine (2NaHCO3 + CaCl2 = Ca(HCO3)2 + 2NaCl). Such a depositional system, integrating the geochemical-depositional controls of sag phase carbonates with those of the South Atlantic evaporites, has important implications for unravelling the genesis of these exotic deposits.

Color adjusting compositions of meat systems with low content of hemoglobin-containing raw materials

The development of technologies for new types of salty meat products with a high level of safety requires the improvement of the basic technological processes of their production, using intensive methods of influence on the raw materials processed, especially in the conditions of the work of domestic enterprises on defective and marked signs of PSE and DFD raw materials (DFD – drу , firm, dark; PSE – pale, soft, exudative). The purpose of the research is the scientific substantiation of the directed use of multicomponent bristles in the technology of salty meat products, in particular, the study of the mechanism of forming the coloring of meat systems with different levels of content of immiglobin raw materials at the stage of its salting with the inclusion in the composition of the brine of nitrite salt instead of sodium nitrite and natural dyes Apro Red and Vepro 70 Col R. According to research results, the replacement of sodium nitrite with nitrite salt leads to an increase in the content of nitrosopigments, which enables to receive a finished product with a lower content of residual nitrite and better color characteristics than equivalent intake and sodium nitrite. Based on theoretical and experimental researches, the analysis of the compatibility of the constituent components, their synergistic influence, the specifics of the functional and technological properties and the results of the influence on the organoleptic, functional-technological and biochemical parameters of the model meat systems, the composition of the multicomponent color-correcting brines is substantiated and developed. The rational concentration of hemoglobin preparations Vepro 70 Col R and AproRed for the coloring of meat systems with the content of glucose-free glycogen up to 15% and the level of injection of more than 140% (respectively, 0.5 and 0.7%) with simultaneous use of 0.05% isoascorbate Na and 0.006% sodium nitrite. It was established that the combined use of nitrate salt and preparations of hemoglobin of blood reduces the residual amount of sodium nitrite twice from the norm established in State Standart of Ukraine due to a more complete transformation of nitrite in nitro compounds. The results of spectrophotometric studies allowed to conclude that the most effective color-correction effect in the formation of pinkish-red shades of model emulsions is Vepro 70 Col R. The possibility of adjusting the color of salted meat products by using multicomponent brines, enhances the efficiency of utilization of raw material resources of the meat processing industry

Smart water flooding performance in carbonate reservoirs: an experimental approach for tertiary oil recovery

Smart water flooding as a developing technique utilizes modified water chemistry in terms of salinity and composition to prepare the best-suited brine composition for a specific brine/oil/rock system to obtain higher oil recovery efficiency. Huge amount of unrecovered oil is expected to be remained in carbonate reservoirs; however, few research works on incremental oil recovery during smart water injection in carbonate cores at reservoir condition are reported. Several core flooding tests using one of the Iranian carbonate reservoir rock are conducted to check the effectiveness of smart water injection for more oil recovery efficiency. The results reaffirm the positive effect of sulfate ions to play a key role for better smart water performance. Moreover, it was concluded that the calcium ion concentration is not as effective as magnesium ion for the tests performed at reservoir condition. Synthetic sea water (high-salinity) flooding was considered as the base scenario which results in almost 63% oil recovery efficiency for secondary recovery scenario. Formation of micro-emulsions was found to be the main reason of additional pressure drop during low-salinity water flooding. This clearly showed that the diluted smart water injecting increases the ultimate oil recovery up to 4–12% for already water-flooded carbonate reservoirs.

Effect of brine composition on yeast biota associated with naturally fermented Nocellara messinese table olives

The study aims to assess the yeast biota associated with table olives of the cultivar Nocellara messinese naturally fermented using different brines. Microbial counts, physico-chemical parameters, and yeast consortia was evaluated at days 0, 3, 7, 15, 30, 60, 90, 180, and 240. Yeasts were identified by PCR-RFLP of the 5.8S ITS rRNA region and sequencing of D1/D2 domain of the 26S rRNA gene. At the fermentation end, the yeast population was assessed by PCR-DGGE analysis. Throughout the eight months of fermentation, the brine modification determined different evolution of the yeast species. The salt concentration shift from 5% to 8% delayed the growth of some species at the end of the fermentation. The experimental brine acidification determined a growth of Pichia mexicana and Saccharomyces cerevisiae that were not found in the other brine formulations. Pichia kudriavzevii was the most isolated species followed by Wickeramomyces anomalus, Zygoascus hellenicus, Candida boidinii, Saccharomyces cerevisiae, Candida aaseri, Candida tropicalis, Candida diddensiae, Zygoascus meyerae, and Pichia mexicana. P. kudriavzevii and W. anomalus species were present in all the processed olives. Some of the strains exhibited suitable technological properties so they could be good candidates as starter in table olive fermentations.

Hydrochemistry as a tool for interpreting brine origin and chemical equilibrium in oilfields: Zubair reservoir southern Iraq case study

The oil reservoir brines are very common geological fluids coexisting with hydrocarbons. The chemistry of brines is a powerful tool for determining the brine evolution and its origin, constraining fluid flow at the basin and predicting reservoir scales. This study targeted the Zubair brines in seven oilfields and investigated the geochemical evolution of brine compositions. The composition of the Zubair brine is characterized by the high average of TDS (219,408 mg/l). The contribution of cations as epm% are Na (73.7), Ca (17.32), Mg (7.45), and K (1.27), while anions contribute as Cl (99.6), SO4 (0.23), HCO3 (0.08), and CO3 (0.005). The Zubair brines are of Na–Ca–chloride type, whereas sodium content is 6.3 times greater than seawater; Ca and Mg contents are thirty-four and three times greater, respectively, while Cl is seven times greater. The SO4 ion is depleted to 0.16, due to a biodegradation. The salinity of the Zubair brine is six times more than that of seawater. The Zubair brines are characterized by an acidic pH (5.24–5.68) with a specific gravity of 1.1436, hydrocarbon saturation in pore spaces of 39%, and water saturation of 61%. The mineral saturation model indicates that Zubair brines are unsaturated. The predicted hypothetical salts are NaCl (76%), CaCl2 (15%), and MgCl2 (7.5%). The salts Ca(HCO3)2, CaSO4, and KCl together form only 1.6%. The Zubair brines are characterized by Cl/Br (305) in average, greater than that of seawater (289) confirming the fluids (brines and hydrocarbons) migrated upwards from Sargelu Formation to Zubair reservoir through fractures and cracks in Gotnia Formation.

Geochemical Modeling and Microfluidic Experiments To Analyze Impact of Clay Type and Cations on Low-Salinity Water Flooding

The types of clay minerals and cations are the factors controlling improved recovery from low-salinity water (LSW) injection. In this paper, a surface complexation model was developed to predict the clay surface charge that develops for different brine compositions and salinities. It was followed by microfluidic experiments to visualize the individual performances of illite, kaolinite, and brine compositions and salinities during LSW injection. An automated measurement was conducted using an algorithm that determines contact angles from pore-space images. Our model results were substantiated against microfluidic observations. Based on the observations coupled with the simulation results, it is concluded that in kaolinite as an edge-charge-dominated clay, the charge development is significant under differing pH and ionic strengths. Accordingly, it responded well to LSW in the system under study, whereas illite as a basal-charged clay did not. This could elucidate the unlike sensitivities of clays to LSW, w...

Investigations into ice scaling during eutectic freeze crystallization of brine streams at low scraper speeds and high supersaturation

Eutectic Freeze Crystallization (EFC) is a potentially cost-effective method to treat reverse osmosis (RO) brines, through the simultaneous crystallization of ice and salt. A major operational challenge, limiting the implementation of EFC in industry, is the formation of an ice scale layer on heat exchanger surfaces. This research determined the influence of the heat transfer driving force, hydrodynamics and brine composition on the severity of ice scaling during continuous EFC of a Na2SO4-H2O system. Experiments were conducted in a hybrid crystallizer-separator with a scraped 2 L crystallization zone. The research focussed on high heat transfer driving forces and slow scraping rates. A unique induction time for scale formation was observed for each set of process conditions. The induction time increased with the increase in scraper speed and decreased as the heat transfer driving force increased. The increase in induction time at higher rotational Reynolds number was attributed to faster distribution of supersaturation, as the flow regime became more turbulent, and more efficient scraping of ice off the wall. The scaling potential decreased as the magma density increased until a certain threshold was reached where it increased again due to the solids impeding effective mixing and heat transfer. Scaling tendencies were reduced during crystallization of multi-component brine streams as compared to binary streams.

Impact of Brine/CO2 exposure on the transport and mechanical properties of the Mt Simon sandstone

Abstract When sandstone rocks are exposed to CO2-saturated brine, their transport and mechanical properties can change due to brine/CO2-induced chemical reactions. The present study investigates the change in the flow-through characteristics, porosity, and the mechanical behavior of Mt. Simon Sandstone samples caused by exposure to brine/CO2. The cores, extracted from a depth interval of 2110.4–2111.4 m (6924–6927 ft) in the Mt. Simon formation, were first characterized for their mechanical and transport properties, and then aged in CO2-saturated brine at pressures of 17.24 MPa (2500 psi) and temperature of 50 °C for one to two weeks. Following that, the changes in the transport and mechanical properties of the samples were analyzed using He pycnometry, flow perporometry and triaxial testing. Our experiments show that the porosity of the Mt. Simon samples slightly increases after exposure to CO2/brine, while the permeability increases more substantially depending on the stress state. Measurements of the flow-through pore size distribution (PSD) are indicative of the changes occurring and are consistent with the observed increases in permeability. Nitrogen adsorption tests (BET), before and after incubation, show a significant loss of pore volume in the mesoporous range that is indicative of clay dissolution. Weakening of the materials was observed based on the mechanical properties studied, a result that is consistent with the observed dissolution of clays that play a central role in the cementation of the quartz grains. Finally, the analysis of the brine compositions reveals an increase in concentration of most cations after incubation with the Mt. Simon cores. This is also consistent with mineral/clay dissolution, confirmed by the porosity, transport, and mechanical property measurements as well as electron microscopy analysis of the same samples.

AgF desalination procedure for the routine determination of oxygen and hydrogen isotopic composition of saline waters and brines

ABSTRACTThe routine methods for stable oxygen and hydrogen isotope analysis of water involve water–CO2 gas equilibration and water reduction on hot metal (e.g. Zn, Cr, U) and subsequent mass spectrometric analysis of the evolved gases of CO2 and H2 for 18O/16O and 2H/1H ratios, respectively. Precise determination of the isotopic composition of water in brines with application of these standard methods is still problematic and technically often impossible due to detrimental influence of dissolved salts. The new method of brine desalination presented in this study overcomes the problem of the isotope salt effects encountered during the application of the routine techniques for the determination of the isotopic composition of high saline waters. The procedure combines two technical steps: (i) the chemical precipitation of Mg and Ca ions as insoluble non-hydroscopic fluorides, and (ii) the vacuum distillation of water from solution–precipitate mixture. The application of simple vacuum distillation allows full extraction of water and dehydration of remaining salts in a temperature range from 300 to 350 °C without hydrogen and oxygen isotope fractionation. The precision and accuracy of δ18O and δ2H determination of saline waters and brines with prior application of AgF desalination procedure is comparable with that usually obtained for fresh waters.

The effect of a phosphonate-based antiscalant on the morphology and precipitation kinetics of gypsum: The Red Sea – Dead Sea project

The proposed plan for the 'Red Sea – Dead Sea project' has raised concerns that the surface water of the Dead Sea would turn white due to gypsum precipitation. The occurrence of such an event would depend on the precipitation kinetics and the morphology of the precipitating crystals. Batch experiments were conducted to study the effect of a phosphonate-based antiscalant on the precipitation kinetics and morphology of gypsum under the conditions of this project. Addition of the antiscalant was found to increase the induction time by a factor of 1.2-5 over the entire range of Dead Sea – Seawater mixtures investigated, depending on brine composition. Once nucleation occurred, the antiscalant also slowed the crystal growth by a factor of 1.2-3. However, when the solutions were seeded with gypsum, the rate of crystal growth with and without antiscalant were similar, within uncertainty. More crystals precipitated from unseeded solutions with no antiscalant and the crystals were smaller and less tabular than those precipitated from unseeded solutions with antiscalant.

Primary data on the impact from trap magmatism on the hydrogeochemistry of brines in the southwestern part of the Kureyka syncline (Siberian Platform)

The new data on the trap magmatism affecting the hydrogeochemistry of brines in southwestern Kureyka syncline in the west of the ancient Siberian platform are presented. The brines occurring in Paleozoic and Proterozoic deposits have salinity (total dissolved solids) varying broadly: from 30.2 to 469.6 g/dm3 for Na Cl, Na-Ca Cl, Ca-Na Cl, Ca-Mg Cl and Ca Cl types, among which the mixed types (Ca-Na Cl and Na-Ca Cl) are found prevailing. The activity of intrusive trap magmatism in the contact zone (with a strike length of up to 400 m) facilitated the disintegration of organic compounds in the free and water-dissolved form (CH4, C2H6, C3H8, iC4H10, nC4H10, iC5H12, nC5H12, C6H14, I, B, NH4). The reaction of the intruding traps brines interaction significantly affected the initial composition of brines, showing a shift towards their saturation with iron, aluminum, silica and other components and thus bearing the evidence of possible salt-induced metal extraction from magmatic melts into an ore-bearing fluid.