Simulated Crude Oil Research Articles

Electrical resistivity imaging of crude oil contaminant in coastal soils – A laboratory sandbox study

Characterizing the subsurface distribution of crude oil after a spill in a coastal environment is challenging due to variations in the soil and fluid properties. In situ sampling is limited in capturing the lateral and vertical migration of the crude oil within the vadose and saturated zones. This study presents a laboratory sandbox framework used to assess the effectiveness of electrical resistivity imaging for investigating the spatiotemporal distribution of crude oil in coastal sandy soils. A sandbox with dimensions L = 240 cm, W = 60 cm, and H = 60 cm was constructed using a 10 mm plexiglass and filled to a 40 cm height with 2 mm medium to fine-grained sand. At each stage of the experiment, 20 kg of sand was mixed with 1 l of water to create moist sand, after which the mixture was flushed over 12 h to remove suspended fine particles. Both saturated and unsaturated conditions were simulated by setting the water table at 10 cm and draining a fully saturated system overnight. Two liters of crude oil were spilled and monitored for 30 h. A surface array of 98 electrodes, with a unit electrode spacing of 2 cm, was installed along two transects 12 cm apart. Resistivity measurements were collected using a dipole-dipole array before, during, and after the simulated crude oil spill. The time-lapse electrical resistivity results revealed an initial gravity-induced vertical migration under both saturated and unsaturated conditions; over time, lateral migration of crude oil became apparent. In the saturated zone, there was a noticeable reduction in the percentage difference in resistivity from 700 % to 400 % after 24 h, depicting a spatial and temporal redistribution of the crude oil attributed to variation in pore geometry. This highlights the sensitivity of electrical resistivity measurements to subtle but measurable anisotropy in the distribution of soil pores. Overall, electrical resistivity proved successful in imaging the non-ideal behavior of crude oil pollutants and the associated spatial changes in the pore-size distribution of subsurface sediments.

Synthesis and Characterization of Acidic Activated Carbon from Corncobs for Adsorption Desulfurization of Simulated Crude Oil

Synthesis and Characterization of Acidic Activated Carbon from Corncobs for Adsorption Desulfurization of Simulated Crude Oil

Effect of tetrakis(hydroxymethyl)phosphonium sulfate (THPS) on the microbial community and corrosion of carbon steel in a simulated crude-oil storage tank environment

The biocorrosion process has been a problem for the oil and gas industry, involving deterioration of facilities, loss of oil quality, metal loss, and oil leaks. In oil storage tanks, the presence of a metallic surface along with crude oil and water poses a biocorrosion risk. Biocides are used to control the biocorrosion of different metallic infrastructures, tetrakis(hydroxymethyl)phosphonium sulfate (THPS) is commonly used due to its low environmental impact and its effectiveness in preventing sulfate-reducing bacteria (SRB) growth. The treatment effect with one THPS application on microbial community and corrosion rates was evaluated in a batch fractionated assay containing water from a crude oil storage tank, carbon steel coupons and crude oil. The effects of the treatment were monitored for 60 days. The number of planktonic bacteria and archaea estimated by qPCR decreased at the beginning of the treatment with THPS, however, 60 days after the application their number was higher, as were the sulfate-reducing microorganisms (SRM) and methanogens (MA). The diversity analysis of the 16S rRNA gene showed that the relative abundance of the genus Desulfovibrio and Methanocalculus was higher on day 8 in the presence of THPS, but by day 60 there were no differences. The biocide did not inhibit bacterial and archaeal biofilm attached to the SAE 1010 carbon steel coupons and produced a decrease in corrosion rates by blocking the surface. The proximity of the corrosion potential to the pitting potential indicated a high susceptibility to localized corrosion. The results suggested that the changes in the microbial community by THPS treatment were related to the corrosion rates of carbon steel, rather than the number of microorganisms attached to the coupon.

Crude oil sorption capacity of modified and unmodified biowaste

Contamination of water by crude oil is ubiquitous particularly in developing countries. The governments of affected countries raise a lot of concern because of the associated economic and environmental impacts which are not in tandem with the United Nations Sustainable Development Goals (SDGs), 6, 8, 11, 13 & 14. Remediation of crude oil-impacted water and soil become imperative. However, the exercise is expensive; hence the search for cheaper and local alternatives. In this study, unsegregated wood sawdust was collected from the various wood saw-dust dump sites within the main Timber shade in the vicinity of Udu Bridge, Udu LGA of Delta State, Nigeria. One half of the sample was chemically modified by acetylation using acetic anhydride while the other half wasn’t. They were characterized using Fourier Transformed Infra-Red Spectrophotometer (FTIR) and Scanning Electron Microscope coupled with Electron Dispersive X-ray (SEM/EDX) analyzer before employing them in the removal of the crude oil from the simulated crude oil spill- water media. The obtained results indicated that the modified sorbent (wood sawdust) sorbed more crude oil than the unmodified sorbent (wood sawdust). Experimental process control factors limited to time, sorbent dosage, particle size, was investigated using the modified sawdust. The modified sorbent gave maximum oil absorption capacity of 5.228 gg-1 for sorption time, 4.759 gg-1 for sorbent dosage and 5.838 gg-1 for particle size analyses. The study contributes to the knowledge of sorption studies using unsegregated wood sawdust for remediation of crude oil-contaminated media.

Interfacial dilatational rheology and displacement mechanism of nano‐flooding system

AbstractIn the field of crude oil extraction, nano‐flooding technology can significantly improve the oil displacement efficiency and provide important technical support for tertiary oil recovery. Although a host of studies have been carried out in this domain, its dilatational rheology and displacement mechanism are rarely reported. In order to address this gap in the extant literature, as a crucial component of this investigation, the interfacial rheology of the nano‐flooding system and the simulated crude oil was systematically studied with the aid of the JMP2000A interface expansion rheometer. Meanwhile, a micro‐displacement experiment was carried out to elucidate its displacement mechanism. The obtained results show that the nano‐flooding system initially increases as its concentration, solution pH, and aging time increase, after which a decline is observed. However, with the change of salinity, it shows a trend of increasing first and then decreasing. Moreover, according to the multi‐factor test results yielded by the relevant software, the relative error is less than 5%, which fully meets the needs of the field and provides an important basis for the field construction. The findings further suggest that the modulus between the nano‐flooding system and the simulated crude oil can be increased by 84‐fold (i.e., from 0.9271 to 78.0739 mN/m). In addition, during the displacement process, the fingering phenomenon of the displacement fluid can be reduced via piston‐like displacement. The swept volume also improves the oil washing efficiency of crude oil, demonstrating that the proposed strategy achieves the purpose of enhancing oil recovery.

Synthesis and Demulsification Properties of Poly (DMDAAC-co-DAMBAC) (9:1) Copolymer.

Utilizing the copolymerization modification of dimethyl diallyl ammonium chloride (DMDAAC), the high positive charge density of the copolymer could be maintained, thereby facilitating the deficiency of its monomer in the application. In this paper, poly (DMDAAC-co-DAMBAC) (9:1) was synthesized with an aqueous polymerization method using DMDAAC and methyl benzyl diallyl ammonium chloride (DAMBAC) as monomers and 2,2'-azobis [2-methylpropionamidine] dihydrochloride (V50) as an initiator. Targeted to the product's weight-average relative molecular mass (Mw), the response surface methodology (RSM) was used to optimize the preparation process. The optimal process conditions were obtained as follows: w (M) = 80.0%, m (V50):m (M) = 0.00700%, m (Na4EDTA):m (M) = 0.00350%, T1 = 50.0 °C, T2 = 60.0 °C, and T3 = 72.5 °C. The intrinsic viscosity ([η]) of the product was 1.780 dL/g, and the corresponding double bond conversion (Conv.) was 90.25 %. Poly (DMDAAC-co-DAMBAC) (9:1) revealed a highest Mw of 5.637 × 105, together with the polydispersity index d (Mw/Mn) as 1.464. For the demulsification performance of simulated crude oil O/W emulsions, the demulsification rate of poly (DMDAAC-co-DAMBAC) (9:1) could reach 97.73%. Our study has illustrated that the copolymerization of DMDAAC and a small amount of DAMBAC with poor reactivity could significantly improve the relative molecular weight of the polymer, enhance its lipophilicity, and thus the application scope of the polymer.

Bioaugmentation enhance the bioremediation of marine crude oil pollution: Microbial communities and metabolic pathways.

Bioaugmentation is an effective strategy used to speed up the bioremediation of marine oil spills. In the present study, a highly efficient petroleum degrading bacterium (Pseudomonas aeruginosa ZS1) was applied to the bioremediation of simulated crude oil pollution in different sampling sites in the South China Sea. The metabolic pathways of ZS1 to degrade crude oil, the temporal dynamics of the microbial community response to crude oil contamination, and the biofortification process were investigated. The results showed that the abundance and diversity of the microbial community decreased sharply after the occurrence of crude oil contamination. The best degradation rate of crude oil, which was achieved in the samples from the sampling site N3 after the addition of ZS1 bacteria, was 50.94% at 50 days. C13 alkanes were totally oxidized by ZS1 in the 50 days. The degradation rate of solid n-alkanes (C18-C20) was about 70%. Based on the whole genome sequencing and the metabolites analysis of ZS1, we found that ZS1 degraded n-alkanes through the terminal oxidation pathway and aromatic compounds through the catechol pathway. This study provides data support for further research on biodegradation pathways of crude oil and contributes to the subsequent development of more reasonable bioremediation strategies.

Integrative Biomarker Indices in a Benthic Indicator Species Modiolus Modiolus (L.) Under a Simulated Oil Spill

The horse mussel Modiolus modiolus (L.) is a sentinel bivalve species used in monitoring programs to assess potential biological exposure to anthropogenic contaminants, including oil hydrocarbons, in benthic environments. In an aquarium based experiment, these mussels were exposed to a simulated oil spill where crude oil at realistic concentrations (from low to high) interacted with an inert environment (seawater, gravel surface, etc.) and the biota. Using a combination of endpoints that included tissue contaminant load, protease activity, antioxidant enzyme activity, and low-molecular antioxidant profiles, we characterized M. modiolus responses to this simulated crude oil spill. Significant differences were observed in tissue protein reserves, protease activity, and oxidative stress markers including glutathione content and glutathione-S-transferase activity in the hepatopancreas and gill tissues of the bivalves treated with oil. Total concentrations of oil-derived polycyclic aromatic hydrocarbons in M. modiolus tissues were generally highest under the highest ambient oil concentration with much lower levels at the lowest. This general pattern does match the activity of protein quality control proteases but not the antioxidant enzyme activity profiles. Glutathione-S-transferase activity in bivalves showed decreased activity under the high compared to the lower oil load and oil-free animals, while glutathione content and calpain activity were positively correlated with oil uptake. The data suggest that these benthic organisms were exhibiting biological responses to the oil polycyclic aromatic hydrocarbons and support the bioindicator value of the species.
 Keywords: M. modiolus, oil spill, PAHs, integrative biomarker approach, protein quality control, GSH, GST

Molecular composition of low-temperature oxidation products in a simulated crude oil In-situ combustion

In-situ combustion (ISC) is a thermal enhanced oil recovery process in which energy is generated by the combustion of a portion of the oil within the reservoir. Low temperature oxidation (LTO) is one of the dominant mechanisms controlling fuel availability in ISC and affects the physical properties of the crude oil, thus the characterization of the crude oil and its LTO products are essential for a better understanding of the ISC process. In this study, a thermal oxidation experiment of a heavy crude oil was carried out to investigate the molecular changes associated to coke formation during ISC. More than half of the component was depleted by combustion or thermal pyrolyzed out, leaving a coke-like solid in the reactor with a yield of a quarter by weight of the crude oil. More than 90% of the coke-like solid is toluene soluble. Condensate oil expelled from the reactor was collected with a yield of about 15 wt% of the crude oil. Small-molecule oxidation products, such as ketones, fatty acids, phenolic compounds were identified in the condensate by GC–MS. High-resolution mass spectrometry results showed that the molecular composition of oxygen- and sulfur-containing compounds changed largely, with the generation of highly oxygenated compounds and sulfoxides. A substantial portion of large-molecule hydrocarbons were survived and enriched in the residue. The main components in the toluene insoluble substance, namely oxidation coke, are methanol soluble and composed of highly oxygenated compounds. The results indicate that oxidation and thermal cracking are both the important reaction in the simulated ISC, the molecular composition is instructive for the understanding of pyrolysis and oxidation behavior of coke formation from the crude oil.

Synthesis, Characterization and Demulsification Performance of Polymethylamyldiallylammonium Chloride

The lipophilic modification of dimethyldiallylammonium chloride monomer (DMDAAC) with resulting excellent lipophilic performance can provide an effective way to improve the application performance of the resulting monomers and copolymers. In this paper, polymethylamyldiallylammonium chloride (PMADAAC) homopolymer was prepared by using methylamyldiallylammonium chloride (MADAAC) as the monomeric unit, 2,2’-Azobis(2-methylpropionamide) dihydrochloride (V50) as the initiator and ethylenediaminetetraacetic acid tetrasodium (Na4EDTA) as a metal ion complexing agent via an aqueous solution polymerization method. Using the intrinsic viscosity of the product as the inspection index, the polymerization reaction conditions were optimized by the response surface optimization method, and the optimum conditions obtained were: w(MADAAC)=70.2%, m(V50):m(MADAAC)=2.05%, m(Na4EDTA):m(MADAAC) =0.0141%, T 1=55.0 °C, T 2=60.0 °C and T 3=80.1 °C, with the reaction lasting 9 h (see below). The average value of the intrinsic viscosity ([η]) of the obtained product was 0.84 dL/g, and the monomer conversion degree (Conv.) was 72.77%. The molecular weight characterizations of PMADAAC showed that the highest M w of PMADAAC was 2.380 × 105 and its polydispersity index d(M w/M n) was 1.952 for optimum properties. The results indicated that the introduction of the amyl group could increase the lipophilicity of the diallyl quaternary ammonium salts based on its good water solubility. For the demulsification performance of simulated crude oil O/W emulsions, the demulsification degrees were 88.9% for PMADAAC, 83.6% for polymethylpropyldiallylammonium chloride (PMPDAAC) and 45.5% for polydimethyldiallylammonium chloride (PDMDAAC), all at the same intrinsic viscosity.

Effect of Aerating Duration on Hydrocarbon Biodegradation in a Simulated Crude-Oil Polluted Aquatic Environment Undergoing Bioremediation

The aim of this research work was to determine the aerating duration that would be effective in enhancing hydrocarbon biodegradation rate during bioremediation of crude-oil polluted river. Sediment and river-water were placed in four glass troughs labeled CT (control), A, B, and C. The setups were polluted with crude-oil, and allowed undisturbed for 2 weeks. Subsequently, accessible crude-oil on the surface was removed; bacteria and nutrients were then added. Air was bubbled for 3 hours into setups A, B, and C, at daily, 3 days, and 7 days interval respectively. Aeration was not applied to setup CT. On day 1, 7, 14, and 21, hydrocarbon concentration was determined; populations of total heterotrophic bacteria (THB) and hydrocarbon-utilizing bacteria (HUB) were also determined. The time it will take for hydrocarbons in the setups to biodegraded “completely” was calculated using first-order reaction equation. The results obtained showed that 71.43, 86.39, 83.17, and 15.42 % hydrocarbon degradation were obtained in setup A, B, C, and CT respectively. The time it will take for hydrocarbons in the setups to biodegrade “completely” were 129, 89, 101, and 1079 days for A, B, C, and CT respectively. There was slight reduction in population of HUB in setup CT, fairly stable population in setup A, and increase in population of HUB in setups B and C. It is concluded that aerating crude-oil polluted aquatic environment for 3 hours at 3 days interval will be more effective in enhancing hydrocarbon biodegradation rate during bioremediation.

Process PLS: Incorporating substantive knowledge into the predictive modelling of multiblock, multistep, multidimensional and multicollinear process data

Chemical production processes benefit from intelligent data analysis. Previous work showed how process knowledge can be included in a structural equation modelling framework. While predictive models increase process value, currently available methods have limitations that hinder applicability to many (industrial) processes. This paper describes the Process PLS algorithm which can analyze multi-block, multistep and/or multidimensional processes. Process PLS was benchmarked on a simulated crude oil distillation process. Analysis of 22 empirical data sets from a production process at Nouryon illustrated how Process PLS solves limitations of PLS path modelling. In the analysis of the benchmark Val de Loire data, Process PLS revealed substantially meaningful effects which the recently proposed Sequential Orthogonalized PLS path modelling completely missed. Process PLS is a promising approach that enables data-driven analysis of process data using information on the complex process structure, to demonstrably increase insight in the underlying system, making model-based predictions much more valuable.

Study on the stability of intermediates in the process of enzymatic hydrolysis of phosphatidic acid by phospholipase A1

In the degumming process of crude soybean oil by phospholipase A1 (PLA1), the content of free fatty acids (FFA) in the product increases excessively. In this study, PLA1 was used to hydrolyse simulated crude soybean oil. It was found that the acyl group at the sn-2 position migrated to the sn-1 position, the content of FFA in the oil was as high as 1.26 ± 0.03 g/100 g, and the acyl migration rate was up to 38.9 ± 0.10% after 2.8 h. Under the conditions of H3BO3 addition of 2 g/100 g, pH of 5, enzymatic hydrolysis temperature of 50 °C and enzymatic hydrolysis time of 2 h, the acyl migration rate of sn-2-HPA was 16.8 ± 0.50%, the content of FFA was 1.14 ± 0.02 g/100 g, and the enzymatic hydrolysis efficiency was increased by 28.57 ± 0.07%.

Multimarker approach to assess the exposure of the wild rodent Calomys laucha to a simulated crude oil spill.

A mysterious oil spill occurred in the ocean near Brazil in 2019, which affected coastal areas in northeastern Brazil. When oil pollution occurs in coastal zones, organisms such as small mammals can suffer deleterious effects to their health. This study aimed to evaluate the effects of exposure to contaminated sandy soil with different crude oil concentrations in males of the species Calomys laucha. The exposure to crude oil resulted in multiple health issues for the subjects in the very first days of exposure. Furthermore, the exposure resulted in mutagenic damage to bone marrow blood cells and behavioral and morphological alterations, which were almost always in a dose-dependent form. The present study demonstrates the sensibility of the biomarkers used and highlights that small wild mammals such as C. laucha are useful for predicting environmental damage caused by the exposure to crude oil.

Transport and Degradation of Hydrocarbons in a Simulated Crude Oil Contaminated Vadose Zone Due to Nutrient Percolation

Transport and Degradation of Hydrocarbons in a Simulated Crude Oil Contaminated Vadose Zone Due to Nutrient Percolation

Effect of crude oil spillage on engineering properties of tropical residual soil

Oil exploration in Nigeria causes serious environmental degradation. Little is known about the effects of crude oil spillage on soils found in northern Nigeria where oil exploration started less than two years ago (2018). This research is a comparative analysis of the effect of crude oil on contaminated and uncontaminated soil typically found in northern Nigeria. Five Trial pits were dug at Bayero University Kano, two of the trial pits were filled with 20 litres of crude oil while the remaining three trial pits were left uncontaminated and used as control. The crude oil was allowed to infiltrate into the soil for about six (6) weeks before samples of soil were obtained for laboratory analysis. Maximum dry density (MDD), natural moisture content, California Bearing Ratio CBR value, cohesion, and Atterberg limits test were used to analyse the soils. Average natural moisture content was found to be 21 % for uncontaminated soil and 8% for contaminated soil, the MDD value was 1.80 g/cm3 for uncontaminated soil and 1.67g/cm3 for contaminated soil, the CBR changes from 25 % to 6 % while cohesion decreased by 48 % for the contaminated soil respectively. The results show negative consequences for road and building constructions in the simulated crude oil contaminated area.

Utilization of Airlift Fermenters in the Mass Propagation of Pseudomonas and AureobasidiumSpecies for the Bioremediation of Crude Oil Polluted Aquatic Environments

This study involved the design and fabrication of airlift fermenters for the mass propagation of a consortium of three microorganisms (Pseudomonas aeruginosa, Pseudomonas fluorescence and Aureobasidium pullulans). The efficacy of the blend in the bioremediation of simulated crude oil polluted water systems environments was also tested with a view to generating more data on crude oil degrading microorganisms for bioremediation purposes. The organisms were separately grown on a gyratory shaker at 120 rpm and at 30 °C until notable growths were observed. Equal volume of the grown organisms (500 ml) of mixed culture was used as inoculum for the 4.5 L of medium in the 7 L airlift fermenter. Thereafter, this was transferred into the 45 litres medium in the 70 L fermenter until significant growth was observed at room temperature. Culture broths were withdrawn at intervals for the determination of biomass and residual hydrocarbon concentrations. The product from the 70 L fermenter was introduced into simulated polluted water systems from which samples were withdrawn weekly. Analyses for residual hydrocarbon contents were carried out using appropriate analytical techniques. The results showed that 78.5% hydrocarbon removal was observed in the 7 L fermenter after 72 h, while that of the 70 L fermenter was 97.8% after 180 h of fermentation. Polluted water sample treated with the microbes experienced 96.4% removal after 10 weeks of treatment. It was observed further that the application of NPK fertilizer biostimulant aided microbial activities in the removal of petroleum hydrocarbons than urea, cow dung and poultry droppings. The study has demonstrated that effective bioremediation of crude oil polluted water systems could be achieved through the application of biostimulants with mass propagated crude oil degrading organisms using airlift fermenter systems.
 Keywords: Pseudomonas aeruginosa; Pseudomonas fluorescence; Aureobasidium pullulans; Airlift fermenter; Bioremediation; Biostimulation; Bioaugmentation.

Cement-lime stabilization of crude oil contaminated kaolin clay

Abstract The present study examines the effect of stabilization on the geo-environmental properties of crude oil contaminated kaolin clay. Lime and cement were mixed in a ratio of 1:2 and added to the simulated crude oil contaminated kaolin clay at different percentages (5%, 10%, 15%, and 20%) as a stabilizing binder. Parameters investigated include consistency limits, unconfined compressive strength (UCS), and direct shear, and compressibility and leaching characteristics of the untreated and stabilized soils. The experimental testing reveals a decrease in the consistency limits with addition of the stabilizing binder. Maximum UCS values occurred for 15% cement-lime stabilized kaolin clay at different curing periods (i.e. 0 d, 7 d, 14 d, and 28 d). By increasing the cement-lime content from 5% to 15%, the UCS values of the stabilized clay increase from 185 kPa to 350 kPa and from 785 kPa to 1160 kPa for uncured and 28 d-cured samples, respectively. Both the compression and recompression indices of the contaminated kaolin clay from the consolidation test decrease by 40% and 50%, respectively, with 20% stabilizing binder addition. The leachability of the contaminated clay also reduces with incorporation of cement and lime. According to the scanning electron microscope (SEM) test, addition of stabilizing binder transforms the dispersed structure of contaminated kaolin clay into a knitted flocculated structure. The study shows the effectiveness of cement-lime mix in stabilizing the contaminated kaolin clay and the possible use of stabilized contaminated kaolin clay as an alternative construction material.

Comparative Study of Cashew Nut Shell Liquid and a Commercial Demulsifier for Treating Crude Oil Emulsions

Cashew Nut Shell Liquid (CNSL), a natural phenolic liquid extracted from locally sourced raw materials, and Phasetreat-4633 (a commercial demulsifier) were diluted with xylene and butanol and used as demulsifiers in the treatment of crude oil emulsions. Laboratory simulated crude oil emulsions dosed with different concentrations of CNSL and PT-4633 were the basis for comparison of demulsifier performance via the bottle test method.
 Different factors affecting demulsification efficiency such as; water content, demulsifier concentration, and solvent type were investigated at 10%, 30%, and 50% water content. The data obtained showed that the rate of water separation increases with increasing concentration and water content of the demulsifiers and emulsion respectively. Among the demulsifier-solvent combination employed in this study, Phasetreat-4633 in butanol recorded the most efficient water separation with optimal (100%) separation recorded after 5 minutes at 40 ppm and 50 ppm concentration, 50% water content and 60℃.
 From the obtained results, the investigated demulsifiers have great potential with butanol as a solvent in the resolution of crude oil emulsions in shorter times. This behavior can be attributed to the synergetic effect of butanol as a solvent. Hence, butanol can be regarded as a better solvent substitute to xylene, due to its attributive synergetic effect, low cost and toxicity levels, unlike xylene which is more toxic and expensive.

Changes in the Bacterioplankton Community Structure from Southern Gulf of Mexico During a Simulated Crude Oil Spill at Mesocosm Scale.

The southern Gulf of Mexico (sGoM) is highly susceptible to receiving environmental impacts due to the recent increase in oil-related activities. In this study, we assessed the changes in the bacterioplankton community structure caused by a simulated oil spill at mesocosms scale. The 16S rRNA gene sequencing analysis indicated that the initial bacterial community was mainly represented by Gamma-proteobacteria, Alpha-proteobacteria, Flavobacteriia, and Cyanobacteria. The hydrocarbon degradation activity, measured as the number of culturable hydrocarbonoclastic bacteria (CHB) and by the copy number of the alkB gene, was relatively low at the beginning of the experiment. However, after four days, the hydrocarbonoclastic activity reached its maximum values and was accompanied by increases in the relative abundance of the well-known hydrocarbonoclastic Alteromonas. At the end of the experiment, the diversity was restored to similar values as those observed in the initial time, although the community structure and composition were clearly different, where Marivita, Pseudohongiella, and Oleibacter were detected to have differential abundances on days eight–14. These changes were related with total nitrogen (p value = 0.030 and r2 = 0.22) and polycyclic aromatic hydrocarbons (p value = 0.048 and r2 = 0.25), according to PERMANOVA. The results of this study contribute to the understanding of the potential response of the bacterioplankton from sGoM to crude oil spills.