Upgrading of heavy crude oil in supercritical aqueous fluid in the presence of activated charcoal

The article presents the results of deep processing of heavy crude oil in supercritical aqueous fluid, which makes it possible to significantly reduce the content of sulfur and resinous asphaltene compounds in products, and to increase the yield of light fuel fractions. The possibility of reducing the temperature of upgrading of heavy crude oil due to the presence of active charcoal in the reaction medium is shown. The proposed technology provides environmentally safe and residue-free processing of heavy oil and further production of high-quality hydrocarbon raw materials enriched in low-boiling fractions. Keywords: upgrading; heavy crude oil; supercritical aqueous fluid; activated charcoal.

Mineralogy, Fluid Inclusions, and Oxygen Isotope Geochemistry Signature of Wolframite to Scheelite and Fe,Mn Chlorite Veins from the W, (Cu,Mo) Ore Deposit of Borralha, Portugal

Scheelitization of Mn-bearing wolframite, scheelite, quartz, and Fe,Mn-chlorite veins was identified in the W, (Cu,Mo) ore deposits of Borralha, by optical microscopy, electron-microprobe analysis, and stable isotope geochemistry. Fluid inclusions derived scheelite crystallization temperature was compared with the oxygen isotope temperature estimated. Scheelite was formed mainly during stage I from a low salinity aqueous-carbonic fluid dominated by CO2, where the homogenization temperature (Th) decreased from 380 °C to 200 °C (average of 284 °C). As temperature decreased further, the aqueous-carbonic fluid became dominated by CH4 (Stage II; (average Th = 262 °C)). The final stage III corresponds to lower temperature mineralizing aqueous fluid (average Th = 218 °C). In addition, salinity gradually decreased from 4.8 wt.% to 1.12 wt.%. The δ18OFluid values calculated for quartz-water and wolframite-water fractionation fall within the calculated magmatic water range. The ∆quartz-scheelite fractionation occurred at about 350–400 °C. The ∆chlorite-water fractionation factor calculated is about +0.05‰ for 330 °C, dropping to −0.68‰ and −1.26‰ at 380 °C and 450 °C, respectively. Estimated crystallizing temperatures based on semi-empirical chlorite geothermometers range from 373 °C to 458 °C and 435 °C to 519 °C. A narrower temperature range of 375 °C to 410 °C was estimated for Fe,Mn-chlorite crystallization.

Maximizing Brine Recovery After the Displacement of Reservoir Drill-in Fluids to Reduce Well Cost Via New, Alternate Technology In a Reservoir Offshore Abu Dhabi

Objectives/Scope This paper outlines a new and innovative technology for brine recovery after the displacement of Reservoir Drill-In Fluid Non-Aqueous Fluid (RDF NAF) to Completion Brine and the associated operational, logistical, environmental and economic benefits associated with it. A unique slop treatment technology has been utilized to recover and reuse more than 2,168 bbl per well of expensive contaminated completion fluid to help manage losses and avoid injecting valuable completion fluid into operator's injection well. This has also resulted in reducing impact to the life of the injection well and burden on formation, thereby minimizing impact to subsurface environment and contributing to lower well cost. Methods, Procedures, Process The contaminated brine was transferred from the displacement of RDF NAF to brine and processed using a novel slop treatment technology to reduce the NTU and TSS to completion brine specifications required for completion operations. After displacing the well from RDF NAF to brine, typical contaminants would be RDF NAF and hi-vis spacer (water-based). The oil-contaminated brine was usually transferred to the tanks of the cuttings treatment contractor, treated and injected into the operator's cuttings re-injection (CRI) well. The new procedure isolated the contaminated brine to be processed through the slop treatment technology to separate and remove the oil and solids from the brine. The slop treatment involved passing the contaminated fluid through a decanter, solids particulate filter, three-phase separator and then a polishing filter to process the fluid to the required NTU and TSS specifications. Results, Observations, Conclusions The slops treatment unit was implemented for brine processing in 2020 and since then, the solution has achieved desirable operational, logistical, sub-surface environmental and cost related benefits. 2,168 bbl of expensive, contaminated completion brine has been processed per well, for subsequent reuse in the completion operations. Utilization and implementation of this mechanical process, versus the historical filter press process, at the source has had clear tangible savings that can be achieved in all areas of the operation, due to the capability to process oil-contaminated brine at a higher clarity and also the viscous brine at a faster rate. This new processing strategy allowed the operator to set new standards with regards to the recovery of oil-contaminated brine, in the UAE. Novel/Additive Information This is the first successful processing of oil-contaminated brine to be completed in the UAE utilizing a mechanical technology. This process has established new baselines for the operator to be able to recover oil-contaminated brine. By adapting the existing site-based slop treatment technology, this solution has bridged a gap in the market by using a novel mechanical process to optimize oil-contaminated brine recovery efficiency and maximize returns for operators.

Geomorphology and Geochemistry of Back Arc Basins in the Havre Trough, Southwest Pacific

<p>The Havre Trough back arc system located behind the Kermadec Arc, in the southwest Pacific, is a classic example of an intra-oceanic back arc system. Subduction driven magmatism is focused at the arc front, and melting in the back arc is accompanied by back arc rifting. This study examines the deep back arc basins of the southern Havre Trough. Compared to the well-studied Kermadec Arc front volcanoes, the back arc basins remain poorly explored, yet are important features in understanding key structural and geochemical dynamics of the subduction system. The back arc is characterised by areas of deeper basins and constructional cross-arc volcanic edifices, which had previously been attributed to ‘rift regime’ and ‘arc regime’, respectively. In this study, recently acquired multibeam data was used to produce digital terrain maps that show individual basins within the Havre Trough that host a range of different morphological features, such as elongated ridges, nearly-flat basin floors, and small volcanic cones. Lavas dredged from the 10 basins were analysed, eight of which sample the rift regime and two sample the arc regime. The back arc basin lavas are basalts to basaltic-andesites and show fractionation of olivine + pyroxene ± plagioclase mineral assemblages. Olivine phenocrysts were tested for chemical equilibrium and predominantly show that crystallisation occurred in equilibrium with host melts. However, petrographic features such as dissolution and zoning within plagioclase show evidence of multistage magmatic evolution. Whole rock trace element geochemistry reveals trace element characteristics typical of volcanic arc lavas, such as enrichments in large ion lithophile elements (LILE) and Pb relative to high field strength elements (HFSE). From west to east, the back arc basin lavas show a decrease in NbN/YbN, consistent with trench perpendicular flow and progressive melt extraction towards the volcanic front. There is also a broad correlation between NbN/YbN and distance along the strike of the subduction zone. This may suggest a component of trench parallel flow of the mantle wedge, with increasing depletion northwards, although further evidence is needed to rule out pre-existing mantle heterogeneity. Ba/Th values, which trace the addition of slab-derived aqueous fluids, decrease with distance from the arc front. This indicates that the aqueous fluid component becomes less prominent with increasing distance from the arc front. Conversely, the basin lavas exhibit broadly increasing LaN/SmN values with distance from the arc front. As LaN/SmN can be used to trace the deep subduction component, i.e. sediment melt contribution, greater LaN/SmN suggests increasing contribution of a sediment signature away from the arc front. The parameters that measure recycled component flux are comparable between rift and arc regimes, so it is unlikely that increased volatile fluxing leads to the larger concentrations of magmatic activity displayed in arc regimes. Gill volcano (arc regime) has similar to higher NbN/YbN than lavas from adjacent basins, suggesting increased magmatic activity may in part relate to pockets of more fertile mantle. This study shows that back arcs and associated volcanism can be complicated, further research is integral in determining mechanisms for voluminous magmatic activity spread throughout the back arc.</p>

Geomorphology and Geochemistry of Back Arc Basins in the Havre Trough, Southwest Pacific

<p>The Havre Trough back arc system located behind the Kermadec Arc, in the southwest Pacific, is a classic example of an intra-oceanic back arc system. Subduction driven magmatism is focused at the arc front, and melting in the back arc is accompanied by back arc rifting. This study examines the deep back arc basins of the southern Havre Trough. Compared to the well-studied Kermadec Arc front volcanoes, the back arc basins remain poorly explored, yet are important features in understanding key structural and geochemical dynamics of the subduction system. The back arc is characterised by areas of deeper basins and constructional cross-arc volcanic edifices, which had previously been attributed to ‘rift regime’ and ‘arc regime’, respectively. In this study, recently acquired multibeam data was used to produce digital terrain maps that show individual basins within the Havre Trough that host a range of different morphological features, such as elongated ridges, nearly-flat basin floors, and small volcanic cones. Lavas dredged from the 10 basins were analysed, eight of which sample the rift regime and two sample the arc regime. The back arc basin lavas are basalts to basaltic-andesites and show fractionation of olivine + pyroxene ± plagioclase mineral assemblages. Olivine phenocrysts were tested for chemical equilibrium and predominantly show that crystallisation occurred in equilibrium with host melts. However, petrographic features such as dissolution and zoning within plagioclase show evidence of multistage magmatic evolution. Whole rock trace element geochemistry reveals trace element characteristics typical of volcanic arc lavas, such as enrichments in large ion lithophile elements (LILE) and Pb relative to high field strength elements (HFSE). From west to east, the back arc basin lavas show a decrease in NbN/YbN, consistent with trench perpendicular flow and progressive melt extraction towards the volcanic front. There is also a broad correlation between NbN/YbN and distance along the strike of the subduction zone. This may suggest a component of trench parallel flow of the mantle wedge, with increasing depletion northwards, although further evidence is needed to rule out pre-existing mantle heterogeneity. Ba/Th values, which trace the addition of slab-derived aqueous fluids, decrease with distance from the arc front. This indicates that the aqueous fluid component becomes less prominent with increasing distance from the arc front. Conversely, the basin lavas exhibit broadly increasing LaN/SmN values with distance from the arc front. As LaN/SmN can be used to trace the deep subduction component, i.e. sediment melt contribution, greater LaN/SmN suggests increasing contribution of a sediment signature away from the arc front. The parameters that measure recycled component flux are comparable between rift and arc regimes, so it is unlikely that increased volatile fluxing leads to the larger concentrations of magmatic activity displayed in arc regimes. Gill volcano (arc regime) has similar to higher NbN/YbN than lavas from adjacent basins, suggesting increased magmatic activity may in part relate to pockets of more fertile mantle. This study shows that back arcs and associated volcanism can be complicated, further research is integral in determining mechanisms for voluminous magmatic activity spread throughout the back arc.</p>

Purification of Drug Loaded Liposomal Formulations by a Novel Stirred Cell Ultrafiltration Technique

Background: Presently reported methods for purification of liposomal formulations at laboratory scale have drawbacks of adversely affecting critical quality attributes (CQAs) of liposomes such as particle size, PDI, drug entrapment efficiency, etc., and are also not amenable for large scale processing. Objective: The present study was aimed to explore stirred cell ultrafiltration technique as a novel liposome purification method for removal of unentrapped free drug and excess external aqueous fluid, maintaining the physical integrity of liposomes. Method: Purification of brimonidine loaded liposomes (model formulation) was performed by stirred cell ultrafiltration method, and its functional performance and impact on liposomal particle size, PDI, and entrapment efficiency were compared with two widely used laboratory scale methods, i.e., ultracentrifugation and centrifugal ultrafiltration. Results: The novel stirred cell ultrafiltration method demonstrated liposomal purification within ~30 min with complete liposomal recovery showing minimal processing impact, i.e., ˂0.25 fold rise in particle size, ~0.5 fold rise in PDI, and ~4% loss in % entrapment efficiency, respectively. Whereas ultracentrifugation and centrifugal ultrafiltration methods resulted in ~4 fold and ˃2 fold rise in particle size, ˃10 fold and ˃5 fold rise in PDI, and ˃25% and ~6% loss in entrapment efficiency, respectively. Conclusion: The unique and product-friendly operational features of stirred cell ultrafiltration method demonstrated simple, rapid, and efficient liposomal purification without affecting CQAs of liposomal vesicles. This method was also evidently found to be product-friendly, rugged, versatile, and scalable up to large production batch processing, overcoming major drawbacks of presently used methods.

Fluid evolution from quartz veins in micaschists from the thermal aureole around the Acari batholith, Northeast Brazil

Micaschists that host the Acari batholith (Ediacaran age, 572 to 577 My) are characterized by a large number of quartz veins. The veins are more abundant in higher-temperature metamorphic zones and, together with lower metamorphic zones, form an aureole centered in the batholith. Most of the fluid inclusions are two-phase (H2O-CO2 and liquid/vapor), but three-phase varieties (liquid/vapor/salt cubes; liquid/liquid/vapor) occur locally. The analyzed veins come from the biotite + chlorite + muscovite, biotite + garnet, cordierite + andalusite, and cordierite + sillimanite metamorphic zones. CO2 melting temperatures (TmCO2) vary from -62.6 to -56.7°C, suggesting CH4 and/or N2. Eutectic temperatures (Te) in quartz veins show average values of -30.8°C in the biotite + chlorite + muscovite and biotite + garnet zones, and -38.6°C in the cordierite + andalusite and cordierite + sillimanite zones. Ice-melting temperatures (Tmice) are lower in the higher-temperature metamorphic zones. The mode values are -3.8, -5.5, -5.6, and -7.3°C, corresponding respectively to the biotite + chlorite + muscovite, biotite + garnet, cordierite + andalusite, and cordierite + sillimanite zones. A fluid characterized by the H2O-Na-Cl (KCl)-MgCl2-FeCl2-CaCl2 system is defined by: Tmice from near -1.9 to -32°C, the presence of salt cubes mainly in the cordierite + andalusite and cordierite + sillimanite zones, and recorded eutectic temperatures (Te) from -16.5 to -59.1°C. In addition, total homogenization temperatures (Tht) ranging from 117 to 388°C were obtained for primary aqueous fluid inclusions. This indicates a long period of fluid circulation under conditions of falling temperatures. Our results are consistent with an increase in the salinity of the aqueous fluid across the thermal aureole toward the granitic batholith.

Volatile transport of metals in the andesitic magmatic-hydrothermal system of White Island

<p>Volcanic gases observed at active volcanoes originate from the magma at depth. These volatiles exsolve as a result of decompression, crystallization and cooling of the silicate melt. The transport of metals in a magmatic volatile phase arises from complexation with the main volatile species, sulfur and halides. Composition of the magma, temperature, pressure and redox state have thus strong implications on metal mobility in these environments. Moreover, a variety of interactions and phase separations can affect these fluids after exsolution from the parental magma. This thesis aims at constraining the volatile transport of trace metals at White Island, a subduction-related magmatic-hydrothermal system, through a characterization and metal budget of the magmatic reservoir and the different atmospheric discharges. The metal content of the reservoir, as well as the effects of degassing and magma mixing on the magma are explored through the study of ejecta from the 1976-2000 eruptive cycle. CO₂, SO₂ and H₂O are degassing from a mafic melt at ~ 5 km depth, regularly feeding a shallower and evolved reservoir at ~ 800 m. Average contents of 164 ppm of Cu, 73 ppm of Zn, 12 ppm of Pb and 0.4 ppm of Au and Ag were detected in melt inclusions. A fraction of these metals partition into the exsolving aqueous fluid. Onset of magnetite crystallization may trigger exsolution of sulphide melt, found to contain around 30 wt% of Cu, and as much as 36 wt% Ni, 21 wt% Ag, 0.10 wt% Au in small inclusions, representing a considerable source of metals available for an aqueous fluid phase upon resorption. The volatile transport of metals is indicated by their enrichment in a variety of discharges at the surface. The hyperacidic waters of the crater lake absorb metals from the magmatic gases injected at subaqueous vents. Concentrations of ~ 12 ppm of As and Zn, 6 ppm of Cu and Pb were observed. Hydrolysis of the host rock by the reactive waters is responsible for the high cation contents of the fluids. Precipitation of secondary minerals such as silica, anhydrite, gypsum, sulfur and alunite occurs within and underneath the crater lake. The predicted speciation of metals greatly varies, dominated by CuI and FeII chloride complexes in the more reduced environment at the lake bottom, whereas CuII and FeIII are stable in the oxidized surficial waters. Arsenic is mainly present as As(OH)₃ at depth, with H₃AsO₄ dominating at the surface. Ag, Pb and Zn are complexed with chloride, and are not redox dependent. The presence of a body of molten sulfur at the bottom of the lake is indicated by sulfur spherules, both floating at the lake surface and in sediments. Pyrite crystals coat the surface of some globules, and chemical analyses reveal an enrichment in a variety of chalcophile metals (Tl, Sb, Bi, Au, As, Ag. Re, Cu). The volcanic gases emitted at fumaroles are enriched in metals compared to the magma. The effective transport of Se, Te, Sb, B, Au, As, and Bi is indicated by enrichment factors larger than 1000. In contrast, Cu is relatively depleted, suggesting deposition in the subsurface environment. Variations in composition are observed with time, mainly depending on temperature and major composition of the emissions. Values > 100 ppb of Sb, Bi, Ni, Zn, As and Se, > 10 ppb of Te, Pb, and Cu, and up to 8 ppb of Tl were recorded. Chloride is predicted to be the main ligand responsible for metal transport, even at higher temperature. The lack of thermodynamic data for complex solvated metal clusters may nevertheless bias our results. The low temperature of the studied fumaroles (maximum 192.5 °C) is in accordance with the small abundance of sulfides in the sublimates, whereas the high proportion of sulfates indicates oxidized conditions. The volcanic plume is enriched in metals such as Bi, Cd, Tl, Se, Te and Sb. The most common particles emitted are sulfates, halides, silicates, sulphuric acid and Zn ± Cu oxides. Metal emission rates are in the range of 1-10 kg/day for As, Se, Cu and Zn, 0.1-1 kg/day for Pb, Tl and Bi. Emissions of high-temperature magmatic gases are indicated by elevated SO₂/HCl ratio and the presence of Au in the particulate phase. Mass balance calculations in White Island magmatic-hydrothermal system indicate a segregation of around 4900 tons of copper per year, either accumulated from a dense brine at ~ 500 m depth, or deposited by low-density vapors on their way to the surface. Metal-rich sulfide blebs trapped in phenocrysts may also retain Cu at depth. These results thus reinforce the belief that White Island is an actively forming porphyry copper deposit.</p>

Volatile transport of metals in the andesitic magmatic-hydrothermal system of White Island

<p>Volcanic gases observed at active volcanoes originate from the magma at depth. These volatiles exsolve as a result of decompression, crystallization and cooling of the silicate melt. The transport of metals in a magmatic volatile phase arises from complexation with the main volatile species, sulfur and halides. Composition of the magma, temperature, pressure and redox state have thus strong implications on metal mobility in these environments. Moreover, a variety of interactions and phase separations can affect these fluids after exsolution from the parental magma. This thesis aims at constraining the volatile transport of trace metals at White Island, a subduction-related magmatic-hydrothermal system, through a characterization and metal budget of the magmatic reservoir and the different atmospheric discharges. The metal content of the reservoir, as well as the effects of degassing and magma mixing on the magma are explored through the study of ejecta from the 1976-2000 eruptive cycle. CO₂, SO₂ and H₂O are degassing from a mafic melt at ~ 5 km depth, regularly feeding a shallower and evolved reservoir at ~ 800 m. Average contents of 164 ppm of Cu, 73 ppm of Zn, 12 ppm of Pb and 0.4 ppm of Au and Ag were detected in melt inclusions. A fraction of these metals partition into the exsolving aqueous fluid. Onset of magnetite crystallization may trigger exsolution of sulphide melt, found to contain around 30 wt% of Cu, and as much as 36 wt% Ni, 21 wt% Ag, 0.10 wt% Au in small inclusions, representing a considerable source of metals available for an aqueous fluid phase upon resorption. The volatile transport of metals is indicated by their enrichment in a variety of discharges at the surface. The hyperacidic waters of the crater lake absorb metals from the magmatic gases injected at subaqueous vents. Concentrations of ~ 12 ppm of As and Zn, 6 ppm of Cu and Pb were observed. Hydrolysis of the host rock by the reactive waters is responsible for the high cation contents of the fluids. Precipitation of secondary minerals such as silica, anhydrite, gypsum, sulfur and alunite occurs within and underneath the crater lake. The predicted speciation of metals greatly varies, dominated by CuI and FeII chloride complexes in the more reduced environment at the lake bottom, whereas CuII and FeIII are stable in the oxidized surficial waters. Arsenic is mainly present as As(OH)₃ at depth, with H₃AsO₄ dominating at the surface. Ag, Pb and Zn are complexed with chloride, and are not redox dependent. The presence of a body of molten sulfur at the bottom of the lake is indicated by sulfur spherules, both floating at the lake surface and in sediments. Pyrite crystals coat the surface of some globules, and chemical analyses reveal an enrichment in a variety of chalcophile metals (Tl, Sb, Bi, Au, As, Ag. Re, Cu). The volcanic gases emitted at fumaroles are enriched in metals compared to the magma. The effective transport of Se, Te, Sb, B, Au, As, and Bi is indicated by enrichment factors larger than 1000. In contrast, Cu is relatively depleted, suggesting deposition in the subsurface environment. Variations in composition are observed with time, mainly depending on temperature and major composition of the emissions. Values > 100 ppb of Sb, Bi, Ni, Zn, As and Se, > 10 ppb of Te, Pb, and Cu, and up to 8 ppb of Tl were recorded. Chloride is predicted to be the main ligand responsible for metal transport, even at higher temperature. The lack of thermodynamic data for complex solvated metal clusters may nevertheless bias our results. The low temperature of the studied fumaroles (maximum 192.5 °C) is in accordance with the small abundance of sulfides in the sublimates, whereas the high proportion of sulfates indicates oxidized conditions. The volcanic plume is enriched in metals such as Bi, Cd, Tl, Se, Te and Sb. The most common particles emitted are sulfates, halides, silicates, sulphuric acid and Zn ± Cu oxides. Metal emission rates are in the range of 1-10 kg/day for As, Se, Cu and Zn, 0.1-1 kg/day for Pb, Tl and Bi. Emissions of high-temperature magmatic gases are indicated by elevated SO₂/HCl ratio and the presence of Au in the particulate phase. Mass balance calculations in White Island magmatic-hydrothermal system indicate a segregation of around 4900 tons of copper per year, either accumulated from a dense brine at ~ 500 m depth, or deposited by low-density vapors on their way to the surface. Metal-rich sulfide blebs trapped in phenocrysts may also retain Cu at depth. These results thus reinforce the belief that White Island is an actively forming porphyry copper deposit.</p>