Algerian Oil Field Research Articles

Simultaneous removal of crude oil and heavy metals by highly adapted bacterial strain Cutibacterium sp. NL2 isolated from Algerian oilfield.

Investigating the ability of bacteria to simultaneously enhance hydrocarbon removal and reduce heavy metals' toxicity is necessary to design more effective bioremediation strategies. A bacterium (NL2 strain) isolated from an Algerian oilfield was cultivated on crude oil as sole carbon and energy sources. Molecular analyses of the 16S rRNA gene sequence placed the strain within the Cutibacterium genera. This isolate was able to tolerate up to 60% of crude oil as sole carbon source. Chemical analyses (GC-MS) evidenced that strain NL2 was able to degrade 92.22% of crude oil (at optimal growing conditions: pH 10, 44 °C, 50 g L-1 NaCl, and 20% of crude oil (v/v) as sole carbon source) in only 7 days. NL2 isolate was also able to produce biosurfactants with reduction of surface tension of growing media (29.4 mN m-1). On the other hand, NL2 strain was able to tolerate high lead (Pb) and copper (Cu) concentrations (up to 60 mM). In fact, NL2 cultivated in the presence of 20% of crude oil, and 0.48 mM of Pb was able to reduce Pb concentration by a 41.36%. In turn, when cultivated on high Pb concentration (15 mM), the strain was able to remove 35.19% of it and 86.25% of crude oil, both in a time frame of 7 days. Our findings suggest that Cutibacterium strain NL2 is able to efficiently use and remove a wide range of crude oil substrates in presence of high Pb concentration. Accordingly, NL2 strain is of extreme interest from a biotechnological standpoint.

Cultural-Loaded Words in Journalistic Translation Between Arabic and English

An increasing number of contributions have appeared in recent years on culturally loaded words. This translation needs familiarity with cultural, linguistic and semantic features. Some news is full of culturally loaded words, strange terms and one of them is the religious or in general term ‘political words’ which play a key role in journalism translation through times. The cultural terms in journalism translation are definitely difficult and controversial to some journalist translators. This difficulty maybe because of the differences between different cultures, religions, ideologies, and beliefs. Translation of political writing or journalistic article needs great cultural familiarity with L1 and L2 and the targets receivers by the translator. Therefore; effective methods were provided to solve culture-bound problems in journalism translation from Arabic into English.
 This article suggests an article from CNN News translated into Arabic entitles“ Islamists Take Foreign Hostages in Attack on Algerian Oil Field” will be taken as a case study. The researcher applies some examples in the languages of English and Arabic to make the statements more clear. The main objective of this present paper is to show the problem of culturally loaded words in journalistic writing and explain different translations used in this article from English to Arabic. After analyzing all the samples, it has been also determined that the ideologies and politics influence the way used in journalistic translation which means that the journalist translator is not free but under the censorship of CNN Agency. Moreover; in this paper, the various cultural words must be translated in their own context in order to establish their significance when translated into another language and culture and the target audiences and amateurs must be convinced of this type of translation.

Identification and Phylogenetic Analyses of Anaerobic Sulfidogenic Bacteria in Two Algerian Oilfield Water Injection Samples

Corrosion of metallic oilfield pipelines by microorganisms is a costly but poorly understood phenomenon. For the first time, sulfidogenic communities in injection waters of two Algerian oilfields, Tin Fuin Tabankort (IT3) and Stah (IS2) were examined using the 16S rRNA gene cloning and sequencing approach. Water samples were inoculated into selective medium for sulfate-reducing bacteria and incubated under anaerobic conditions at 45 °C. The total number of culturable sulfidogenic microorganisms in the samples obtained from the two sampled waters (IT3 and IS2) was 2.4 × 105 cells/mL and 3.9 × 104 cells/mL, respectively. Scanning electron microscopy analyses showed different morphological forms reflecting the diversity of sulfidogenic communities. 16S rRNA gene sequencing and phylogenetic diversity analyses revealed that both water reservoirs harbor large amounts of anaerobic bacteria. However, a majority of all the sequences analyzed (e.g., 34% in the IS2 and 84% in the IT3 samples) were not assigned to any known bacterial group, suggesting that subsurface waters harbor very large sulfidogenic anaerobic microbial communities of as yet undescribed bacterial phyla. Proteobacteria were found to be the most dominant phylum in the IS2 sample (49%); however, no Proteobacteria were detected at the IT3 production well. The Firmicutes phylum (10%) was detected in the two water samples, whereas Bacteroidetes phylum (7%) was retrieved only in IT3. The most abundant related genera were: Desulfotomaculum, Porphyrobacter, Hyphomicrobium, Acidocella, Comamonas, Ramlibacter, Pseudomonas, Enterobacter and Flavitalea. No shared operational taxonomic units were observed among the two samples analyzed, demonstrating the uniqueness of each subsurface water well. This study demonstrates the diversity of the sulfidogenic bacteria that might play a critical role in the souring mediated corrosion of metallic oilfield pipelines. This information could help oilfield companies develop better anticorrosion treatments and strategies.

Reservoir compartmentalization and fluid property determination using a modular dynamic tester (MDT): case study of an Algerian oil field

Compartmentalizing the reservoir and determining its initial properties are key steps in the development of an oil field. These steps are mainly performed to determine the number and types of fluids in the reservoir. They are also carried out to establish the initial reservoir pressure and reservoir potential. For each fluid zone, it is essential to identify the fluid present and its range. The oil reservoir examined in the present case study consisted of different zones with ambiguous fluid limits. Thus, the pressure gradients and variations in this reservoir were measured using a modular formation dynamics tester (MDT). This device can be employed to discriminate between formation fluids in real time. An analytical analysis of the measured pressure gradients allowed the reservoir compartments to be defined, taking into account the types of reservoir fluids present. The investigation also aimed to identify the initial reservoir conditions and establish the free water level (FWL) in each fluid zone. Thus, with similar setting, reservoir characterization and heterogeneity may constitute a key factor approach to be examined. The oilfield analyzed in this work, which is part of the Hassi Berkine basin in the Saharan platform (southeastern Algeria), has an anticlinal structure. From a sedimentological point of view, it consists of fluvial-continental deposits. Some erosional effects of the Hercynian unconformity influence the top of the Frasnian clays present. The main hydrocarbon reservoir is located in the Lower Triassic Clayey Sandstone (TAGI), the current name for the Triassic reservoir in the Sahara platform in the investigated area. The TAGI is divided into three levels: the upper TAGI (TAGI-U), middle TAGI (TAGI-M), and lower TAGI (TAGI-L). Data revealed several pressure gradients along the depth profile of each borehole section, implying significant changes in fluid properties. Substantial differences in pressure between oilfield boreholes (e.g., between the boreholes through TAGI-U+M and TAGI-L) were observed. The equivalent densities for the pressure gradients indicate that the fluid succession in the deposits is oil (TAGI-U+M), water (TAGI-M), and then oil again (TAGI-L). A stratigraphic barrier between TAGI U+M and TAGI-L was identified. By superimposing the pressure gradients observed in wells 1 and 2, two reservoir compartments were deduced. Furthermore, based on the pressure evolution with depth and the density record, two free water levels (FWL) in addition to the initial pressure were identified for the reservoir.

Microbacterium algeriense sp. nov., a novel actinobacterium isolated from Algerian oil production waters.

A non-motile, straight-rod-shaped, Gram-stain-positive and facultative anaerobic bacterium (i.e., strain G1T) was isolated from production waters from an Algerian oilfield. Growth was observed in the presence of 0.3-3.5 % (w/v) NaCl, at 20-50 °C and at pH 6.0-9.0. Results of phylogenetic analyses based on 16S rRNA gene sequences showed that strain G1T belonged to the genus Microbacterium. Strain G1 T was closely related to Microbacterium oxydans (DSM 20578T) and Microbacterium maritypicum (DSM 12512T) with 99.8 % sequence similarity and to Microbacterium saperdae (DSM 20169T) with 99.6 % sequence similarity. Strain G1 T contained MK9, MK10, MK11, MK12 and MK13 as respiratory quinones, and phosphatidylglycerol, diphosphatidylglycerol and glycolipid as the major polar lipids. The major cellular fatty acids were anteiso-C15:0, iso-C16:0 and anteiso-C17:0. The estimated DNA G+C content was 69.57 mol% based on its draft genome sequence. Genome annotation of strain G1T predicted the presence of 3511 genes, of which 3483 were protein-coding and 47 were tRNA genes. The DNA-DNA hybridization (DDH) and average nucleotide identity (ANI) values between strain G1T and M. oxydans (DSM 20578T) and M. maritypicum (DSM 12512T) were in both cases far below the respective species boundary thresholds (27.5 and 28.0 % for DDH; and 84.40 and 84.82% for ANI, respectively). Based on the data presented above, strain G1T was considered to represent a novel species for which the name Microbacterium algeriense is proposed with the type strain G1T (=DSM 109018T=LMG 31276T).

Drill Bit Deformations in Rotary Drilling Systems under Large-Amplitude Stick-Slip Vibrations

In oil and gas industry, rotary drilling systems are used for energy exploration and productions. These types of systems are composed of two main parts: mechanical and electrical parts. The electrical part is represented by rotating motor called top drive; however, the mechanical part of the system is composed of tool string with many pipes, at the bottom end of these pipes the bit is attached to cut the rock during their contact. Since the bit is in a direct contact with rock characteristic variations, it can be under risk for heavy damage. The latter is principally caused by the fact that the rock–bit interaction term is highly nonlinear and unpredictable. In literature, many mathematical models have been proposed for rock–bit interaction, but they do not reflect the dynamic of the bit under vibrations since torsional and axial vibrations are strongly coupled and synchronized with it. In industrial development, the design of drill bit has faced many improvements in order to overcome these vibrations and mitigate unpredictable phenomena. Even though, the practical use of these drill bits confirmed that there are still many failures and damages for the new designs; moreover, bits’ virtual life become shorter than before. The objective of this study is to analyze the drill bit deformations caused by the stick-slip vibration phenomenon which is characterized by high-frequency high-amplitude in rotary drilling systems. The obtained results were validated through a case study of MWD (measurement while drilling) data of well located in a Southern Algerian oil field.

Modeling asphaltene precipitation in Algerian oilfields with the CPA EoS

One of the major flow assurance problems afflicting the oil industry is the asphaltene precipitation during the production, transportation and storage of oil. The precipitation of these heavy compounds is responsible for changes in crude oil properties, increases in oil viscosity, and formation of deposits that reduce oil production and disable equipment leading to significant operational costs. In Algeria, the deposition of asphaltene in reservoirs and pipelines is a severe problem. During production the depressurization of reservoir fluid and the variations of thermodynamic conditions create the need to frequently pig the lines and, in some cases, to inject solvents and dispersants to maintain the production. The understanding of the asphaltene behavior and the prediction of its deposition in flow conditions is crucial to implement appropriate strategies for the prevention or remediation, especially in the wellbore region. In this work we used the CPA EoS to describe the asphaltene phase envelope and predict the PT regions of stability for five Algerian live oils. The model provides a very good description of the experimental behavior of live oils without and with gas injection. The sensitivity to SARA analysis data and its effect on the asphaltene phase boundaries were also analyzed.

Diesel Biodegradation Capacities and Biosurfactant Production in Saline-Alkaline Conditions by Delftia sp NL1, Isolated from an Algerian Oilfield

In this study, a diesel oil-degrading bacterium was isolated from an oilfield water injection (water-bearing formations, 1,205 m depth) in Algeria. The bacterial strain, designated NL1, was cultivated on diesel oil as sole carbon and energy sources. Molecular analyses of the 16S rRNA gene sequence (KY397882) placed NL1 strain closely related to distinct cultivated species of the Delftia genus. Optimal diesel oil biodegradation by Delftia sp NL1 strain occurred at pH 11, 40 °C, 2 M NaCl and initial hydrocarbon concentration of 5% (v/v) as sole carbon source. GC-MS analyses evidenced that strain Delftia sp NL1 was able to degrade more than 66.76% of diesel oil within only 7 days. On the other hand, and in the same conditions, biosurfactant production by Delftia sp NL1 was also evaluated evidencing high emulsifying capacity (E24 = 81%), ability to lower the surface tension of growing media (with the value of 25.7 mN m−1), and production of glycolipids (8.7 g L−1) as biosurfactants. This research presents indigenous strain Delftia sp NL1 for diesel degradation and synthesis of biosurfactant in extreme conditions. In this sense, strain NL1 is a good candidate for possible in situ oil recovery and in wastewater treatment in refineries and oil terminals in petroleum industry.

Experimental design methodology as a tool to optimize the adsorption of new surfactant on the Algerian rock reservoir: cEOR applications

In this research work, a new surfactant called surf EOR ASP 5100 used in the SWCTT (single well chemical tracer test) in the Algerian oilfield and sodium dodecyl sulfate (SDS) were used for static adsorption tests. The Algerian rock reservoir has been characterized by different techniques such as SEM, XRD, XRF, BET analysis. The equilibrium was successfully verified by Langmuir isotherm and second-order ( $R^2>95\%$ models for all concentrations and temperatures to predict the adsorption process. Furthermore, the adsorption process was found to be exothermic ( $\Delta G^{\circ}<0$ . To quantify the minimal adsorbed quantity, a full factorial design of 23 (8 experiments) was applied to analyze the individual effects and interactions of operational parameters using variance analysis (ANOVA), desirability method and response surface methodology. The optimal conditions obtained are as follows: the Qe value was 2.3291mg/g for the SDS surfactant at a concentration of 200ppm and temperature of $ 25 {}^{\circ}$ C, and Qe was 3.894513mg/g for EOR ASP 5100 for the concentration of 200ppm and temperature of $ 80 {}^{\circ}$ C.

Chemical Prevention of Asphaltene Flocculation in Oil Production System

The change of pressure, temperature or chemical composition of crude oil during oil production constitute the factors that may destabilize the heaviest fraction of crude oil presented in asphaltenes leading to many problems in the production system including the alteration of reservoir rock wettability, permeability reduction, plugging of tubing and production aerial facilities which generate a high production cost because of loss in the well productivity and the need of corrective measures. In this work, a crude oil sample was taken from an Algerian oil field to study the efficiency of two commercial inhibitors. The flocculation onset point of asphaltenes was measured by a solid detection system which is based on the light transmittance of flocculated particles when n-heptane is added. The effectiveness of two inhibitors was evaluated by the solid detection system at different concentration to select the best inhibitor, however, the best additive should provide a good performance at low concentration. Meanwhile, the effect of thermodynamic conditions has been also established in this work, however, the operator conditions of pressure and temperature have affected the efficiency of the added inhibitor on the flocculation of asphaltenes.

A Comprehensive Study on Crude Methanolic Extract of Daphne gnidium L. as Effective Corrosion Inhibitors of Mild Steel Induced by SRB Consortium

The aim of the present work is the evaluation of effect of methanolic extract obtained from Daphne gnidium against biocorrosion caused by sulphate-reducing bacteria (SRB). Herein, the study of the influence of SRB consortium has been realized on the biological and electrochemical properties of the carbon steel API5LX60 immersed in water sample obtained from an Algerian oil field separator. The monitoring of the treatment effects on the SRB performance using kits test and weight loss methods showed a positive effect of the methanolic extract of D. gnidium as a corrosion inhibitor at a concentration of 0.8 g/L. In the other hand, the weight loss test has generated an efficiency rate of 95.99% at a concentration of 1.6 g/L. A linear polarization resistance approved these results, and they have given a yield of 91.14% with a polarization resistance value of 28.9 kΩ cm2 at a concentration of 0.25 g/L.

Diversity of Microbial Communities in Production and Injection Waters of Algerian Oilfields Revealed by 16S rRNA Gene Amplicon 454 Pyrosequencing.

The microorganisms inhabiting many petroleum reservoirs are multi-extremophiles capable of surviving in environments with high temperature, pressure and salinity. Their activity influences oil quality and they are an important reservoir of enzymes of industrial interest. To study these microbial assemblages and to assess any modifications that may be caused by industrial practices, the bacterial and archaeal communities in waters from four Algerian oilfields were described and compared. Three different types of samples were analyzed: production waters from flooded wells, production waters from non-flooded wells and injection waters used for flooding (water-bearing formations). Microbial communities of production and injection waters appeared to be significantly different. From a quantitative point of view, injection waters harbored roughly ten times more microbial cells than production waters. Bacteria dominated in injection waters, while Archaea dominated in production waters. Statistical analysis based on the relative abundance and bacterial community composition (BCC) revealed significant differences between production and injection waters at both OTUs0.03 and phylum level. However, no significant difference was found between production waters from flooded and non-flooded wells, suggesting that most of the microorganisms introduced by the injection waters were unable to survive in the production waters. Furthermore, a Venn diagram generated to compare the BCC of production and injection waters of one flooded well revealed only 4% of shared bacterial OTUs. Phylogenetic analysis of bacterial sequences indicated that Alpha-, Beta- and Gammaproteobacteria were the main classes in most of the water samples. Archaeal sequences were only obtained from production wells and each well had a unique archaeal community composition, mainly belonging to Methanobacteria, Methanomicrobia, Thermoprotei and Halobacteria classes. Many of the bacterial genera retrieved had already been reported as degraders of complex organic molecules and pollutants. Nevertheless, a large number of unclassified bacterial and archaeal sequences were found in the analyzed samples, indicating that subsurface waters in oilfields could harbor new and still-non-described microbial species.

Biocorrosion of carbon steel by a nitrate-utilizing consortium of sulfate-reducing bacteria obtained from an Algerian oil field

The biooxidation of sulfide under denitrifying conditions is a key process in the control of souring in oil reservoirs and in the treatment of gas and liquids contaminated with sulfide and nitrate. The effect of nitrate injection on the microbial community has been evaluated in the setting of offshore oil industry production, but has not been studied onshore, such as in the Algerian oilfields. A consortium of sulfate-reducing bacteria (SRB) was isolated by first inoculating saline Postgate’s medium C with injection water obtained from the In Amenas oil field, situated in the South Eastern Algerian Sahara, and then exposing the test solution to sulfate. When nitrate was dosed at 120 mg/l it was reduced by this bacterial consortium, with some ammonium production. This mechanism could be important in oilfield systems where nitrate is applied to prevent sulfide generation by SRB that leads to reservoir souring. In static tests, the influence of this SRB consortium on corrosion was assessed using carbon steel coupons, in the presence of sulfate alone and sulfate with 120 mg/l nitrate. The results of the static test indicate that the occurrence of pitting corrosion was fairly low under this condition. This is the first report on the use of nitrates in the fight against corrosion in the Algerian oil industry.

Antagonistic activity of Bacillus sp. obtained from an Algerian oilfield and chemical biocide THPS against sulfate-reducing bacteria consortium inducing corrosion in the oil industry

The present study enlightens the role of the antagonistic potential of nonpathogenic strainB21 against sulfate-reducing bacteria (SRB) consortium. The inhibitor effects of strainB21 were compared with those of the chemical biocide tetrakishydroxymethylphosphonium sulfate (THPS), generally used in the petroleum industry. The biological inhibitor exhibited much better and effective performance. Growth of SRB in coculture with bacteria strain B21 antagonist exhibited decline in SRB growth, reduction in production of sulfides, with consumption of sulfate. The observed effect seems more important in comparison with the effect caused by the tested biocide (THPS). StrainB21, a dominant facultative aerobic species, has salt growth requirement always above 5% (w/v) salts with optimal concentration of 10-15%. Phylogenetic analysis based on partial 16S rRNA gene sequences showed that strainB21 is a member of the genus Bacillus, being most closely related to Bacillus qingdaonensis DQ115802 (94.0% sequence similarity), Bacillus aidingensis DQ504377 (94.0%), and Bacillus salarius AY667494 (92.2%). Comparative analysis of partial 16S rRNA gene sequence data plus physiological, biochemical, and phenotypic features of the novel isolate and related species of Bacillus indicated that strainB21 may represent a novel species within the genus Bacillus, named Bacillus sp. (EMBL, FR671419). The results of this study indicate the application potential of Bacillus strainB21 as a biocontrol agent to fight corrosion in the oil industry.

Shale problems and water-based drilling fluid optimisation in the Hassi Messaoud Algerian oil field

Drilling fluid formulation and properties play a fundamental role in drilling operations. Clay minerals behave initially as a beneficial rheological adjuvant in drilling muds. Nevertheless, the contamination of oil reservoirs by clay minerals present in the drilled geological formation (shales) may generate major problems during drilling as plug formation. In this context, our study deals with the optimisation of drilling conditions in the Hassi Messaoud Algerian field. The mineralogical heterogeneity of this field is first discussed. The rheological and filtration characteristics of water-based muds with different polymer and electrolyte concentrations are investigated. The physical and chemical changes of both drilled formation and drilling fluid during the drilling process are studied. Therefore, depending on the clay present in the geological formation, an optimised drilling fluid system using a new filtration procedure is proposed. A good correlation is found between filtration/rheological properties and inhibition.