Showing papers by "Sonatrach published in 2011"

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

Abstract: The present study enlightens the role of the antagonistic potential of nonpathogenic strain B21 against sulfate-reducing bacteria (SRB) consortium. The inhibitor effects of strain B21 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). Strain B21, 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 strain B21 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 strain B21 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 strain B21 as a biocontrol agent to fight corrosion in the oil industry.

Life-Cycle Impact Assessment of oil drilling mud system in Algerian arid area

Abstract: The objective of this work is to assess the environmental impacts of the drilling mud system in Algeria's arid region. Water-based mud (WBM) and oil-based mud (OBM) are used during well drilling in Hassi Messaoud petroleum field, and have a considerable pollution potential particularly on the aquifer system which constitutes the single resource of drinking water in the Sahara. The Life-Cycle Assessment (LCA) approach is applied to evaluate the impacts of several drilling mud systems across all stages of their life cycle, e.g. use, treatment and disposal. Environmental impacts of five treatments scenarios corresponding to the drilling waste management applied in Hassi Messaoud are compared: reserve pit without treatment (burial option), secondary high centrifugation (vertical cuttings dryer), stabilisation/solidification online, stabilisation/solidification off line and thermal desorption. The impact assessment is carried on using the LCIA models of Impact 2002+ method in SIMAPRO7 software. This assessment identifies human toxicity and terrestrial eco-toxicity as the major impact categories in this specific arid context and quantifies the emissions contributions. The local environmental impact is the most important of the drilling mud life cycle and is mainly linked to emissions from reserve pits, treated cuttings, and drilling phase 16″ through the Turonian and Albian aquifer. The main contributing substances are aromatic hydrocarbons fraction and metals in particular barium, zinc, antimony, arsenic, and aluminium. Concerning the comparison of the treatment scenarios, it appears that stabilisation/solidification online is the best one; it has the lowest impact score in the two dominating categories because of the waste minimisation: mud storage avoided in the reserve pit. The second best scenario is the thermal desorption which obtains the lowest impact score in carcinogen effects due to hydrocarbons reduction (<1%) and avoided impacts of recovered oil. The toxic substances fate modeling will be improved by taking into account their site-specific impact.

Study of API 5L X52 Carbon Steel Treated in Oxygen Plasma Discharge

Abstract: Oxidation in oxygen plasma of API 5L X52 carbon steel samples was realized in glow electric discharge, under primary vacuum of 8.10-2 torr for a period of 50 hours, under tension discharge of -1000 V and a sample current of 15 mA. The treated steel samples have been characterized through microscopic observations; optical microscopy and Scanning Electronic Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS) microanalysis. These observations permit to reveal microstructural modifications arising from the treatment in oxygen plasma discharge. X Rays Diffraction (XRD) investigation has been realized for the crystallographic characterization of surface modification. The steel samples submitted to the glow discharge show a good surface aspect, with blue black color. Microscopic observations of samples at different stages of treatment, show structural modifications of steel’s surface. SEM observations show surface morphology changes after treatment, and EDS analysis reveal an oxygen implantation within the steel. XRD investigation shows the formation of an iron oxide (Fe2O3) on the surface of the steel specimens after treatment.