Brazilian Oil Research Articles

Preparation and characterization of patauá and pracaxi Brazilian vegetable oil emulsions

In this work, the stability of oil-in-water emulsions (O/W) of patauá (Oenocarpus bataua) and pracaxi (Pentaclethra macroloba) oils, both from Amazon rainforest, was investigated. Low-energy emulsification methods were used, such as Emulsion Inversion Point (EIP) and Phase Inversion Temperature (PIT), both based on the minimal interfacial surface, combined with optimized Hydrophilic-Lipophilic Balance (HLB). Phase inversion was determined by electrical conductivity measurements. The surfactants used were Span® 80, Tween® 20, Tween® 60, and Tween® 80. Surfactant mixtures of Span® 80 + Tween® 80 were the best samples prepared. The composition of the most stable samples was 80.00 wt% aqueous phase, 15.00 wt% nonionic surfactants, and 5.00 wt% oil phase (patauá or pracaxi oil). The samples with the best kinetic results were those prepared with the required HLB and PIT values of 12.86 and 84.05 °C, for patauá oil, and of 9.61 and 79.50 °C for pracaxi oil. The kinetic stability of the oil emulsions was characterized by creaming index (CI), by evolution over time of the droplet size, viscosity, and electric conductivity. The results showed that: (1) the droplet size distribution influenced electric conductivity; (2) the relative amount of surfactants Tween® and Span® used is more important to determine the physicochemical and interfacial properties of the emulsion than the oil identity itself; (3) it is crucial to pay attention to the influence of air bubbles—involuntarily inserted into the mixture during the emulsification process—in the physicochemical properties of the system. These conclusions can be extended to other oil-in-water emulsions.

Comprehensive composition and comparison of acidic nitrogen- and oxygen-containing compounds from pre- and post-salt Brazilian crude oil samples by ESI (-) FT-ICR MS

The discovery of the pre-salt oil field renewed and expanded the outlook of the Brazilian petroleum industry due to the large volume of oil and its composition. The chemical composition characterization of crude oils from different reservoirs is crucial for the petroleum industry. In this study, comprehensive profiles of polar acidic nitrogen- and oxygen-containing compounds were accessed by electrospray ionization (ESI) in negative mode coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) for a set of five Brazilian crude oil samples from the pre-salt layer, and these were compared to the chemical composition of four crude oils from post-salt reservoirs. The ESI (-) FT-ICR MS data showed that the N-containing compounds present high relative abundance among the heteroatomic compounds identified for pre- and post-salt crude oils, which was more notable for the pre-salt crude oils. Comparing the heteroatomic profiles of the pre- and post-salt crude oils, the N2, NO, and O classes were seen to decrease in relative abundance in the post-salt crude oil, whereas the NO2 and O2 classes increased in relative abundance. The acyclic to cyclic acid (A/C) ratio of the O2 class was used as a parameter to classify the pre- and post-salt crude oils. The high content of acyclic O2-containing compounds (A/C ratio > 1.2) indicated that the pre-salt crude oils are more preserved from microbial alteration, leading to the formation of O2-containing compounds, while an A/C ratio < 0.2 for post-salt crude oils categorized them as more biodegraded. A modified A/C ratio that included aromatic O2 compounds, analyzed in a ternary diagram, was also used to classify the oils according to their families: pre- and post-salt crude oils. Considering the O2-containing compounds with 1, 3, and 5 DBE (double bond equivalents), it was possible to group these oils according to their reservoirs. In addition, alkylphenols with DBE = 4, 5, and 6 also demonstrated a tendency to identify the oils according to their pre- and post-salt reservoirs. The petroleomic approach shown here by comprehensive FT-ICR mass spectrometry analysis is a powerful tool for differentiating crude oils from pre-salt and post-salt reservoirs.

The Marriage of the Octopus and the Hammerhead Shark and How That Relates To Making Money on Old Offshore Fields

PetroRio is a young, Brazilian independent oil producer whose acquisitions tend to raise the same question: “How do you make money from old brownfields? That is the question we have always heard,” said Iuri Rossi, subsea coordinator at PetroRio. The answer has existed since small companies began buying the discards from big oil companies looking for the next giant field—cut costs and invest some of the earnings to extend the productive life of the existing platform. At this year’s Offshore Technology Conference (OTC), Rossi provided an example by describing how PetroRio acquired two nearby fields in the Campos Basin to create a single, profitable unit (OTC 31900). It began with the acquisition of the Polvo field (Portuguese for “octopus”) in 2016, shortly after the launch of the privately owned company. The purchase from BP included a floating production platform and a costly leased floating, production, storage, and offloading (FPSO) vessel capable of handling many times the 8,000 B/D output of the aging field. The value of the Octopus field became apparent only in 2020 after the company made two more acquisitions: First, it purchased an FPSO on the nearby field Tubarão Martelo (Portuguese for “hammerhead shark”); later that year it also bought the field. Those deals offered a solution—build a pipeline from the Polvo platform to the Tubarão Martelo FPSO and dump the leased FPSO. The $45 million spent to marry the field saved $50 million a year, generating cash to support a future that will include more drilling, Rossi said. The cost-cutting moves also included small deals such as buying an obsolete drilling rig for $1.00, then getting it running again and using it to work over wells. “We bring a new mindset; so, we say, ‘let’s try it,’” Rossi said. New thinking and more investment in the Campos are what Brazil needs as Petrobras and other big companies sell off smaller holdings in the rich basin that made the country a major oil producer before the ultradeepwater pre-salt play in the Santos Basin eclipsed it. But there is a lot of oil left in the Campos. Equinor reported that its partnership with Petrobras has a goal of adding 1 billion bbl of production to the Roncador field alone (OTC 31729). Still, at age 40 it is a mature play, along with the North Sea and the US Gulf of Mexico (GOM). Petrobras recently announced it would allocate $5 billion to work in the Campos from a $20-billion fund to provide the infrastructure needed to promote offshore development. “The Campos Basin plays a very strategic role for Petrobras in the future. Two-thirds of the production [there] in 2026 will come from investments made right now,” said Eduardo Bordieri, executive strategy manager for Petrobras, while presenting a paper on the future of the Campos at an OTC session (OTC 31883).

Shallow Water: The Next Frontier for Deepwater Rigs, or Just a Passing Fad?

Petrobras, one of the world’s top offshore operators, has shared new information about how it used an ultradeepwater rig in a place where it was never intended to work—in shallow water. What makes its recent subsea campaign novel is that the Brazilian national oil company avoided mooring the rig and instead relied on dynamic positioning (DP). Two key pieces of technology made this possible. The first is called a blowout preventer (BOP)-tethering system which sits on the seabed and absorbs much of the load being placed onto the wellhead structure. The second is a digital twin software that determines the safety of the rig’s position during drilling. Petrobras is not the first to accomplish such a feat in depths less than 2,000 ft. But it is among the few to recount its learnings in multiple technical papers as it did at the recent Offshore Technology Conference (OTC) in Houston. The fresh insights surrounding the Petrobras projects stem from an initial well drilled and completed 2 years ago with a sixth-generation drillship, the Norbe VIII, owned by Brazilian contractor Ocyan. The new well is in the Albacora field within the Campos Basin and was the first of several planned to be drilled or plugged and abandoned by Petrobras in DP-only mode. Over a 16-day period in May 2020, the Norbe VIII worked in water depths of about 1,475 ft where it successfully tapped into a pre-salt oil reservoir with a total depth of more than 16,000 ft. For both firms, the project in the Campos Basin marked a first. Never before had they used a rig in DP-only mode at such shallow depths, which amounted to about 15% of the rig’s maximum depth rating. Following the first well, Petrobras drilled at least one more in June 2021 in DP-only mode. Notably, Petrobras was in the midst of selling off the Albacora field during its experimentation with DP-only shallow-water drilling. The mature asset was discovered by the state-run operator in 1984 about 75 miles from the coast and has been producing from post-salt reservoirs for the past 35 years. But earlier this year, the company said it was hoping to fetch a higher price based on better-than-expected reservoir tests from the deeper pre-salt target it drilled in May 2020.

Characterization of crude oils with a portable NIR spectrometer

The characterization of oils by the physicochemical properties analyses is the basis of the industrial chain. Multivariate data analysis seeks to optimize this process through a characterization database. Thus, it is possible to build different models that estimate all these properties with only a data set from a spectroscopic technique. Near-infrared (NIR) spectroscopy is widely used for this purpose. However, there are no studies in the literature using a portable instrument – a technological advance interesting, for example, in field situations. In this study, we evaluate the performance of a portable NIR spectrometer and compare it with a benchtop NIR instrument. We estimate API gravity (°API), total sulfur content (TSC), basic nitrogen content (BNC), saturates hydrocarbons (Sat), aromatics (Aro), resins (Res), and asphaltenes (Asp) from a set of 182 Brazilian crude oil samples. We constructed partial least squares (PLS) and support vector regression (SVR) models. The PLS Asp model obtained the best response with the portable instrument in the wavenumber range from 11,000 cm−1 to 6,000 cm−1. However, the benchtop instrument was superior for the PLS models of the other properties because it operates in the range from 10,000 cm−1 to 4,000 cm−1. The range from 6,000 cm−1 to 4,000 cm−1 is important for this algorithm because it presents the first overtones of S-H, O–H, C–H, and N–H bonds. The accuracy to predict these properties with the portable instrument can be improved with the application of the SVR algorithm. The results obtained with SVR were similar or superior (Sat, Aro, and Asp) to those obtained with the data from the benchtop instrument. For Sat, Aro, and Res, the SVR models still obtained a coefficient of determination (R2) below 0.7. So, other data treatment must be investigated to improve the accuracy of these properties. Even so, the portable instrument has applicability to petroleum analysis. It showed satisfactory results to estimate the properties °API, TSC, BNC, and Asp.

Model-based life cycle control of ICVs in injectors in a benchmark analogous to a pre-salt field

Some fields in the Brazilian pre-salt feature light oil and high gas/CO2 content, which is a bottleneck to oil production due to gas processing restrictions in the facilities. To deal with this, Water-alternate-gas (WAG) is used as a recovery mechanism while the use of Interval Control Valves (ICVs) is also recommended, since these enable controlling the production or injection through segments in the wells.In this context of high gas production and WAG, a good injection management is crucial and the use of ICVs in the injection wells can help to improve the oil production and the field's economic return. In this work, we propose and compare four approaches (A, B, C, and D) to control the ICVs of the injectors considering numerical simulation and Net present value (NPV) as objective function. Approaches A and B use streamlines to correlate producers and injectors, and they also use the Gas-oil ratio (GOR) of the producers as a monitoring variable to close the valves of the injectors. The difference between them is that, in Approach A, the valves remain closed during the entire field's life cycle, while there is an alternation of each opened or closed valve for every WAG cycle in Approach B. In Approach C, the alternation between each valve is made since the beginning of the WAG cycles, instead of waiting for a trigger to start closing the valves. These three approaches are sub-divided into other (minor) approaches, depending on whether the valve remains closed, or not, during the water injection cycles. Finally, in Approach D, we attempt to control the cumulative fluid injection between the zones of the injectors. The study is applied to the SEC1_2022 benchmark case, a synthetic model analogous to a pre-salt field. Finally, we apply the best approach found to a reference case (“true response”) to assess how the proposed strategy would behave in real cases.The results indicate that closing the valves in earlier stages of the field's life cycle is better than using GOR as a trigger. Furthermore, the alternation between opened and closed valves proved to be the best way to control the valves in this case. Approach D was the best among those evaluated, with the highest increase in oil production and greatest decrease in water production, providing highest NPV. Although the platform remained constrained by gas production, this approach provided a better fluid distribution in the field and among wells, improving both oil recovery and economic returns.

Decreasing natural gas flaring in Brazilian oil and gas industry

From 2009 to 2019, Brazil experienced a reduction in its flaring volumes from 16% of the natural gas production to 4%. That was the result of the policy of reducing flaring volumes that started in 2000 and was recently improved. That places Brazil in the 24th position on natural gas volume flaring, with a flaring percent of around 4%. That flaring is compatible with countries with good practices in the oil and gas sector, like the United Kingdom.To identify and quantify the main reasons for flaring natural gas in oil & gas production units, both risk map analysis and future prediction on flaring were employed. The results can lead to the achievement of mid-term reduction with focused regulation. Both tools suggest that regulation improvements must be directed to the flaring in fields with high production of natural gas (especially newer and future ones) and the commissioning of production units.With improvement in regulation, the increase of 100% in natural gas production will possibly result in a decrease in natural gas flaring to around 2% in 2030. Some proposed actions can lead to even lower flaring percentages.

Evaluation of the High-Throughput Screening System for Assessing the Behavioral Response of FemaleAedes aegyptito Natural Products

As part of an arbovirus vector control strategy, chemical control continues to be a mainstay in mitigating the burden of disease. The current arsenal of chemicals used for this purpose, however, are becoming challenged rapidly because of issues of insecticide resistance and environmental pressure. Newer, environmentally friendly actives are of interest to supplement aging chemistries; therefore efforts to screen compounds for insecticidal activity are warranted. This study evaluated the efficacy of the high-throughput screening system (HITSS) for measuring the behavior-modifying actions of Brazilian Cerrado plant extracts, oils, and other compounds against Aedes aegypti. Different concentrations were evaluated, with 8 of 34 samples tested demonstrating either contact irritancy, spatial repellency, or attractiveness. We concluded several natural products screened in this study showed promise for use against mosquito vectors like Ae. aegypti, and that the compact modular HITSS assay constitutes a robust tool for measuring the behavioral responses of mosquitoes in the search for novel insecticides derived from natural products.

SDG Adherence of Social Performance Indicators Used by Brazilian Mining, and Oil and Gas Extraction Companies

This study aimed to examine whether the social performance indicators used by mining companies participating in the BM &amp;amp; FBOVESPA Corporate Sustainability Index (indice de sustentabilidade empresarial [ISE]) during 2005–2021 were aligned with United Nations’ Sustainable Development Goals (SDGs). Content analysis was conducted after collecting key information from voluntary sustainability reports presented by the companies. The results uncovered 423 social indicators and revealed repeated discontinuity and large time gaps of as many as 6 years in the disclosure of sustainability information. Among the SDGs investigated, the most discussed were (in order): SDGs 4, 3, 5, 1, 10, and 2. Thus, it is recommended that even though SDGs have been implemented since 2015, the desired social impact can be created only when companies in the mining and extraction sectors make a formal commitment to continuously disseminate sustainability reports and work equitably on SDG goals.

Characterization of heavy oils from the Campos Basin, Brazil: Free biomarkers in oils, adsorbed and occluded in asphaltene structures

The Campos Basin is considered an important Brazilian petroleum province, with the most of its oils consisting in a mixture of biodegraded and non-biodegraded oils, which is related to more than one generation and migration pulse coupled with biodegradation events during successive stages of reservoir filling. Its turbidites reservoirs are also structural controlled through faults generated by halokinesis comprising the main route of oil migration from underlying source rocks. Throughout the biomarkers analyses of free hydrocarbons in oil, adsorbed, and occluded in the asphaltene structures, samples from different oilfields, and distances from the main fault responsible for its reservoirs filling, were comprehensive studied. The gas chromatography coupled mass spectrometer (GC-MS) methodology was applied. The results of biodegradation, source, and thermal maturation parameters reveals that the free and adsorbed saturated hydrocarbons are similarly altered, but differ in biodegradation degrees and pathways between oils, while occluded hydrocarbons and all fractions of aromatic compounds are well preserved. The predominance of biodegradation process over the recharge is suggested for distant samples from the main fault in each area, contributing to the local models of oil migration. The occluded hydrocarbons showed source similarities regardless of oilfield. According to thermal maturity based on unaltered aromatics compounds, the occluded hydrocarbons showed lower mature ratios than those free. This study introduces the application and limitations concerning biodegradation, source, and thermal maturation inferences from occluded hydrocarbons in asphaltenes covering Brazilian oils, in view to improve a concise geochemical tool in petroleum exploration.

Technical and economic aspects of coke gasification in the petroleum refining industry

Petcoke has applications as an energy source in the industry, serving as fuel for power generation or through the Integrated Gasification Combined Cycle (IGCC) system for the production of syngas and electricity. This kind of technology prioritize the production of electric energy efficiently through a combined cycle integrated with a gasification system. The novelty of this work is the consideration of the use of petcoke for increasing electricity potential generation in the refinery regarding Brazilian conditions. In this paper, it is studied the application of the petcoke gasification in an actual refinery located in the Vale do Paraiba region, São José dos Campos city. In this analysis, thermodynamics studies are carried out on the potential for electricity production and the global efficiency of the process using IGCC technology in the Brazilian oil refinery. Also, economic analysis is applied for the determination of the electricity production cost, the annual saving expected and the payback period of the system. As conclusions, the studies showed a net efficiency in the electricity production of 41.2% with a production capacity of 260 MW. It was found that the specific investment cost of the system was US$ 2719.2/kW and the cost of energy production tends to stabilize at US$ 0.083/kW, and the payback is between 7 and 10 years when the cost of electricity is considered as US$ 0.109/kWh.

Molecular optimization of castor oil maleate as demulsifier for water-in-crude oil emulsions

The formation of stable water-in-oil emulsions is a frequent problem in the oil industry. In general, the difficulty of processing, unwanted water co-production, and damage to machinery are the main issues. Chemical demulsifying additives are used to destabilize petroleum emulsions. In this context, new environmentally friendly demulsifying components are being developed, preferably those produced from low-cost sources. This work synthesized five chemical surfactants based on castor oil maleate (MACO). These additives were characterized by Fourier transform infrared (FTIR), gel permeation chromatography (GPC), and nuclear magnetic resonance (NMR). The demulsification activity was studied through bottle tests on emulsions formulated with two Brazilian oils. A performance scan evaluated different molecular structures and concentrations of the demulsifiers (100 to 5000 ppm) to determine an optimum demulsifier molecular structure. Dynamic interfacial tension measurements were performed to elucidate the demulsification activity at the water-oil interface under the same experimental conditions as the bottle tests. The Ward and Tordai equation was applied according to asymptotic approximations to assess the diffusivity of additives. All results were discussed correlating the demulsifying mechanisms, performance at the interface, and the possibility of applying the additives. All additives showed demulsifying behavior in the form of a water dropper. The demulsifier containing 2.3 mols of maleic anhydride incorporated with 1.0 mol of castor oil showed more significant activity, with a maximum water resolution of 90% for both emulsion systems.

Premixed flame heat release-based optimum global single-step chemistry for H$$_2$$, CH$$_4$$, and C$$_3$$H$$_8$$ mixtures with air

Despite the significant development of comprehensive detailed chemical kinetics mechanisms for combustion simulation in the past decades, reduced descriptions of the chemical process still enable engineering and direct numerical simulations. This work proposes a new formulation for the heat release rate of laminar premixed flame which extends the classical one-step Arrhenius global kinetics using a kinetically controlled assumption for the scalar governing the final reaction steps. The proposed methodology considers that the heat release rate as a function of temperature is known and obtained via a freely propagating laminar premixed flame model together with various detailed chemical kinetics mechanisms. The resulting formulation involves three free parameters, one of which is the Zel’dovich number, whereas the new ones characterize the final heat release stages. The proposed formulation is characterized for H $$_2$$ , CH $$_4$$ and C $$_3$$ H $$_8$$ mixtures with air and compared to several detailed chemical mechanisms, exhibiting errors between 6% and 15% for the first of these and smaller than 6% for the hydrocarbons. The three free parameters are determined for a range of equivalence ratios and seem to be mixture properties. In particular, the Zel’dovich number exhibits a minimum around stoichiometry. The hydrocarbons fuels are also characterized when diluted by CO $$_2$$ , which is motivated by its presence in Brazilian pre-salt oil wells. The new free parameters are not influenced by dilution, whereas the Zel’dovich number is found to increase.

Bayesian prior distribution based on generic data and experts’ opinion: A case study in the O&amp;G industry

Reliability estimation is an essential task to ensure predictability on the life of equipment installed in oil wells, allowing forecasting costs, planning maintenance, and estimating system availability. However, data may be rather scarce and/or expensive to obtain, especially for technologies under development in the Oil and Gas (O&G) industry. The information is frequently available in generic databases and expert opinions. In the Bayesian framework, the prior knowledge about a system's reliability is updated as a new field and/or test data are gathered. This paper proposes an approach that does not require direct elicitation of parameters to define informative prior distributions for the reliability function using fault tree analysis, expert's opinions, and/or generic data at the system level of equipment under development. Specifically, the method-of-moments and maximum-entropy are adopted to propagate downward the uncertainty from the system level through the failure modes until the basic events of the fault tree, weighted by the expert knowledge of the failure behavior. Then, in possession of all prior distributions of the basic events, the information may be propagated upward based on Monte Carlo simulation to update the system reliability distribution. Finally, we present a case study of the proposed methodology applied to a novel open-hole expandable packer, a completion equipment recently installed in a Brazilian oil field. The failure modes and failure causes are discussed, and, after expert elicitation, the definition of the informative prior distribution is achieved. Therefore, we estimate the reliability for a given time and assess if the novel equipment attains the company's risk target, taking O&G standards as reference.

Capitellidae (Annelida) from the Brazilian Continental Margin (SW Atlantic): new occurrences of three genera and description of new species

The Brazilian Continental Margin hosts several deep seafloor landscapes. However, this deep margin is still poorly studied and monitored, compared to coastal and continental shelf areas, historically limited to areas of particular economic interest. Some studies financed by the Brazilian oil and gas company have been conducted off Southeast (SE) Brazil (Esprito Santo and Campos Basins) as part of the environmental licensing process for resource exploration. Similar results showed that annelid polychaetes dominated on the continental shelf and upper slope. Within a wide bathymetric range, Capitellidae species belonging to three different genera represented new records for Brazil: Mastobranchus Eisig, 1887, Peresiella Harmelin, 1968, and Polymastigos Green, 2002. Mastobranchus braziliensis sp. nov. was found in shallow waters (20147m) of both Esprito Santo and Campos Basins; Peresiella megapapilata sp. nov. occurred from 21 to 446m of both Esprito Santo and Campos Basins; and Polymastigos profundus sp. nov. inhabited greater depths (9901361m) of the Esprito Santo Basin only. Three new species are described and compared to other species of the respective genus, the diagnosis of some genera amended and the type material of Mastobranchus loii Gallardo, 1968 redescribed. Although the three genera have the same number of thoracic chaetigers, they present several morphological differences, and the current effort being made is to translate those differences into characters to be included on the generic diagnosis of each genus. Additionally, two new morphological characters were proposed for the family, the shape of thoracic chaetigers and depth of intersegmental groove.

Simulation of the soybean oil hydrotreating process for green diesel production

Renewable diesel, or green diesel, is the biofuel with the fastest growing use in the world. Its use as a replacement for fossil diesel is important to reduce the impact of carbon emissions. Green diesel is formed by a mixture of hydrocarbons with a chemical composition similar to that of fossil fuel, making it a drop-in biofuel. Commercial processing employs hydrotreatment of vegetable oil, which, in addition to producing green diesel, can also be used to produce biofuel for aviation, bionaphtha and biopropane. The present paper proposes a model for the hydrotreatment of soybean oil for the production of green diesel. The process was simulated in Aspen Plus® v10; the decarboxylation, decarbonylation and hydrodeoxygenation reactions were carried out in a stoichiometric reactor in the presence of an NiMo/Al2O3 catalyst. In addition to the cracking reactions and fractionation, the fuels produced green diesel, aviation biofuel, and light gases. Brazilian soybean oil was used as the raw material to produce the green diesel. Sensitivity analyses were performed to adjust the best fractionation conditions, considering the composition of the product and the distillation column energy. The best results were chosen when the distillation column was configured with 22 stages, feed at stage 12 and reflux ratio equal to 0.8. The hydrogen/soybean oil ratio was 0.031. The energy used in the process was 1181 kW/h. More than 80% of the soybean oil was converted to renewable fuels, with approximately 65% to green diesel. In addition, a prediction of the simulated physical chemical properties was made and compared with the current Brazilian legislation for green diesel obtaining values within the established specifications. The ASTM D86 distillation curve was compared with simulated results from green diesel obtained from experimental data and fossil diesel. The experimental and simulated distillation curves agreed, showing only a small difference between curves up to 25% of recovered volume. This can be explained by the lighter components present in the experimental green diesel. The proposed simulation supported the potential of Brazilian soybean oil for the production of quality renewable fuels.

Modeling subsea gas-liquid separation using proxy for phase separation for pre-salt reservoirs with high GOR

Brazilian pre-salt oil fields include ultra-deep water reservoirs with high CO2 content and high gas/oil ratio (GOR). For these cases, large volumes of CO2-rich gas reach the topside facilities that present limited gas processing capacity. In this context, the production of the oil field is restricted to the maximum gas production capacity of these facilities. The use of a subsea gas-liquid separation (SGLS) and reinjection system may be a solution to boost oil production, as this strategy allows reinjecting part of produced gas directly from the seabed. In this study, we developed a methodology for modeling the subsea separation and reinjection process, which is integrated with a compositional reservoir simulator. A proxy based on an equation of state (EOS) was used for volumetric phase separation in the subsea separator. This approach eliminates the necessity of flash calculation at the SGLS conditions. The methodology makes it possible to assess the potential impact of implementing this technology from a reservoir management perspective. The modeling methodology is applied to a benchmark case (synthetic simulation model representative of a pre-salt reservoir) and evaluated the impact of the SGLS over total production. The results show that the SGLS technology can successfully boost oil production in the context of platform gas production restriction. As soon as the SGLS was implemented, an extended oil production plateau was achieved due to increased gas production capacity. We observed a significant GOR increment in produced fluids during the simulation as a result of gas recycling strategy. This increasing GOR caused the field production to be restricted by maximum gas production constraint most of the time, despite the SGLS implementation. A higher GOR also affects the SGLS performance, increasing the proportion of gas that becomes available for separation at subsea separator conditions. An economic analysis is presented, showing that the SGLS has the potential to increase the financial return of the project. The introduced methodology will enable the inclusion of the subsea separation process in future analyses, paving the way for feasibility assessments and optimization processes for cases in which the SGLS may be an alternative.

Brazilian Cerrado biome essential oils to control the arbovirus vectors Aedes aegypti and Culex quinquefasciatus

Insecticides have been used not only to control pests in agricultural production, but also in integrated vector management strategies to reduce populations of mosquitoes, and, consequently, decrease transmission of pathogens they carry. The Aedes aegypti mosquito is a vector of dengue, Zika, chikungunya and yellow fever viruses, whereas the common mosquito Culex quinquefasciatus is a vector of human filariasis and the West Nile virus. Natural insecticides constitute effective ecofriendly alternatives to synthetic control agents. Thus, we investigated the larvicidal, adulticidal and repellent activity of six Brazilian Cerrado plant essential oils extracted by hydrodistillation, together with their major components identified by GC/MS: p-cymene, (R)-(+)-limonene, (S)-(-)-limonene and (-)-β-pinene. The species were selected taking into account the fact they are plants commonly found in this biome, easy to be collected and being still poorly studied in terms of their activity in the Ae. aegypti and Cx. quinquefasciatus. These essential oils demonstrated activity against (i) Ae. aegypti larvae (24 h): Xylopia aromatica (LC50 12.1 µg/mL), Myrcia dictyophylla (LC50 17.6 µg/mL) and Campomanesia adamantium (LC50 18.0 µg/mL); and (ii) Ae. aegypti adults (after 4 h exposure) with the highest knockdown values observed for C. adamantium (93.8%), Blepharocalyx salicifolius (93.4%), M. dictyophylla (92.5%) and X. aromatica (87.2%). These natural product mixtures also demonstrated repellency to (i) Ae. aegypti: Eugenia dysenterica leaves: spatial activity index (SAI) 0.737; weighted spatial activity index (wSAI) 20.229, B. salicifolius (SAI 0.611; wSAI 14.804) and M. dictyophylla (SAI 0.586; wSAI 8.798); and (ii) Cx. quinquefasciatus: E. dysenterica - Protection (P) 71%, C. adamantium (P 61%) and B. salicifolius (P 60%). B. salicifolius leaves essential oil showed both insecticidal and repellent activity. Our results support the use of Cerrado plant essential oils at low concentrations as a promising alternative vector control strategy.

BRAZILIAN OIL PIONEERS

In the Brazilian popular imagination, the discovery of oil was announced on August 9, 1938, by the Viscount of Corncob. The Donabentense Oil Company drilled Caraminguá’s first well, near the creek that passed through the Yellow Woodpecker Ranch (“Sítio do Picapau Amarelo,” in colloquial Portuguese). The latter was the name of a famous Brazilian children’s book. In fact, the first oil well flowed in Salvador, Bahia, on January 21, 1939, discovered by Manoel Ignácio Bastos (1891 - 1940), a Brazilian geographer engineer, whose business partner, Oscar Salvador Cordeiro (1890 - 1970), was the president of the Bahia Commodities Exchange. A brief analysis of documents, such as reports, Brazilian decrees and executive orders, as well as newspapers, detail the actions of these Brazilian oil pioneers. Statistical data analysis was also performed about onshore and offshore oil production between 1941 and 2019, as a part of Bastos and Cordeiros’ heritage.

Molecular Docking in silico Analysis of Brazilian Essential Oils Against Host Targets and SARS-CoV-2 Proteins

The inhibitory activity of thirty-one sesquiterpenes identified from Brazilian essential oils (Copaifera langsdorffii Desf., Croton cajucara Benth. and Siparuna guianensis Aublet.) were analyzed by in silico molecular docking. The compounds were characterized by gas chromatography-mass spectrometry (GC-MS) and gas chromatography with flame-ionization detection (GC-FID), and then, applied against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) proteins and human angiotensin-converting enzyme 2 (hACE2). Applying molecular docking and AutoDock Vina software, a total of 496 individual interactions were detected for sesquiterpenes along with SARS-CoV-2 proteins and hACE2 human angiotensin converting enzyme-2 protein. The findings showed considerable binding affinity of sesquiterpenes with the tested macromolecules. In that, β-selinene from C. langsdorffii displayed the best energy (-7.2 kcal mol-1) and showed strong interactions with the amino acids of the SARS-CoV-2 M-Pro protein. Spathulenol from C. cajucara strongly interacted with human ACE2, with a binding energy of -7.1 kcal mol-1. Meanwhile, γ-eudesmol from S. guianensis presented the lowest binding energy (-7.5 kcal mol-1) by interacting with the SARS-CoV-2 M-Pro complex. Additionally, measurements were performed aiming to evaluate the best sesquiterpenes binding interactions with the main proteins and its homologue files. According to results, these Brazilian essential oils hold antiviral potential being a rich source for further in vitro and in vivo studies focusing on herbal therapeutic adjuvants against SARS-CoV-2 infections.