16 research outputs found
Characterization and geostatistical mapping of water salinity: A case study of terminal complex in the Oued Righ Valley (southern Algeria)
No full textEtude de la Vulnérabilité à la Pollution Chimique des Eaux Souterraines (ZNS) de la Région d'Ouargla, Sud-Est Algérien
No full textEtude de La vulnérabilité à la pollution chimique des eaux souterraines (ZNS) de la région d’Ouargla, Sud-Est Algérien
No full textDans la cuvette d’Ouargla, la pollution des eaux souterraines est un sujet qui inquiète les habitants et les autorités. Ce travail consiste à étudier les causes de pollution des eaux souterraines (ZNS). Nous avons procédé à l’échantillonnage puis à l’analyse, sur site et au laboratoire, de plusieurs puits de la cuvette, afin d’aboutir a une base des données pour résoudre les problèmes qui caractérisent cette dernière. D’après les analyses des eaux souterraines nous avons traité la vulnérabilité des eaux de la cuvette à la pollution ; la carte d’évolution de l’indice de pollution est d’une importance capitale pour la protection contre la pollution
Hydrogeological study of the aquifer system of the northern Sahara in the Algero-Tunisian border: A case study of Oued Souf region
No full textInfluence of Natural Fractures on Oil Production of Unconventional Reservoirs
No full textAbstractIn recent years, awareness of the role of fractures on the production and recovery of hydrocarbons has become increasingly strong in the oil community.To shed light on this question, this paper examines the fractures characterization and their effects on production and enhanced oil recovery; also, it deals with characterization of specific features of fractured reservoirs, using different tools as cores analysis and 3D imagery.The effect of fractures on well productivity is explained and in this point, we have taken the data of wells production from a single reservoir to put these wells at the same overburden conditions. We have selected as example “El Gassi” field to follow the evolution of gas/oil ratio (GOR) according to wells daily production.To analyze the effect of the injection on the daily production of the field, we have compared the evolution of the production of three tanks, two fractured reservoirs and a third non-fractured (consolidated). We took the “El Gassi” and “Rhourde El Bagel” fields as fractured reservoirs, and “Hassi Berkin” field as consolidated one. Then we have treated the impact of fractures on assisted oil recovery; we have studied the response of production at “Rhoud El Bagel” field after gas injection.Data analysis of the production of these three Algerian fields shows that there is no direct apparent relationship between the intensity of fractures and average production. A change in the recovery mode is required by the orientation to water injection or water alternating gas “WAG” process
Surface water and groundwater quality assessment using the WQI method and human health risk assessment (HHR) in the lower seybouse (Annaba Plain), northeast Algeria
No full textThis study was carried out to investigate the current status of surface water and groundwater quality in Lower Seybouse and Annaba Plain, NE Algeria. 36 surface water and groundwater samples were collected in this area, and various physicochemical parameters were analysed. The quality of surface water and groundwater for drinking and the associated health risks were assessed using a Water Quality Index (WQI) and a Human Health Risk Assessment (HHRA) model. The results show that all samples are alkaline with the EC values ranging from 1139 to 5555 μS/cm. The ionic dominance pattern was in the order of Na+ > Mg2+ > Ca2+ > K+ for cations and Cl– > HCO3 – > SO4 2 – > NO3 – for anions, respectively. The dominant water types are SO4-Cl-Ca-Mg and SO4-Cl-Na, formed by dissolution of evaporative and carbonate-rich material. All samples are unsuitable for drinking, with 1 sample classified as poor (rank = 4) and 35 samples as extremely poor (rank = 5). These samples are mainly located near the Seybouse Wadi, which is a natural outlet for wastewater from human activities. The assessment of non-carcinogenic risk showed that the Hazard Index (HI) for males ranged from 0.12 to 1.01 with a mean of 0.30 and only one sample exceeded value 1. For females, the HI was between 0.16 and 1.28 for females, with a mean of 0.39. The risk for children was even higher, ranging from 0.41 to 3.28, with a mean of 1.03, suggesting that children are more vulnerable to water contamination. The Carcinogenic Risk (CR) values for Pb ranged from 10–3 to 8.6 · 10–3, with a mean of 2.6 · 10–3 for males, and between 1.4 · 10–3 to 10–2, with a mean of 3.3 · 10–3 for females, while for children the CR values ranged from 3.5 · 10–3 to 2.7 · 10–3, with a mean of 8.4 · 10–3, indicating that no possible CR from water drinkin
Study of Mineral and Organic Pollution of the Unsaturated Zone (UZ) of the Bowl Ouargla, Southeast Algerian.
No full textAbstractIn the bowl of Ouargla, pollution of groundwater is the main topic that worries people and authorities. This work is to study the causes of groundwater pollution (UZ). We conducted sampling and analysis on site and in the laboratory, the number of wells in the basin in order to achieve has a database to solve the problems which characterize the latter. Based on analyzes of groundwater vulnerability we treated water bowl pollution, map the evolution of the pollution index is of utmost importance for the protection against pollution
Groundwater Geochemical and Quality of the Continental Intercalary Aquifer in Béni Ounif (Southwest Algeria)
No full textThe main objective of this work was to study the status of groundwater quality for drinking and irrigation uses in the locality of Beni Ounif. A total of 16 samples were taken at different locations in the study area from boreholes to capture the continental intercalary (CI) aquifer for physicochemical analysis. This work used the groundwater quality index (GWQI) method to evaluate water potability. The irrigation water quality was assessed by studying EC, SAR, Na%, KR, PI, and MR parameters. In addition, the mechanisms of mineralization of these waters were highlighted by the study of Piper, Gibbs, bivariate diagrams, and the calculation of saturation indices. The results show that the CI waters would have chemical constituents in accordance with the WHO guide values and the Algerian guide values for drinking water. The GWQI method showed a good quality of CI waters for consumption in the study area. On based the irrigation water parameters, the IC water samples are acceptable for irrigation provided that drainage techniques are applied to the cultivated land for tipsy soil salinization. In addition, the study of Piper, Gibbs, bivariate, and mineral saturation diagrams shows that the CI waters of the study area are of Ca-Mg-SO4-Cl type, and the hydrogeochemical processes that control their mineralization are complex, namely, the alteration of silicate and carbonate minerals, the dissolution of gypsum and exchange ion
Recharge and dynamics of the Tamanrasset alluvial aquifer (Algerian Sahara)
No full textInternational audiencePopulation growth and agricultural intensification are ever more demanding in water resources, and threaten their quality and quantity, especially in semi-arid and arid areas. The Sahara desert is typical of these multiple constraints and rapid changes making sustainable management of water resources a major issue. The wide regional aquifers have nearly fossil water. In contrast, alluvial aquifers associated with small wadis are recharged nearly each year by the rare floods. In the case of Wadi Tamanrasset, in southern Algeria, the alluvial aquifer is exploited intensively because of its accessibility and its good chemical quality. The physical conditions commanding flow and recharge of groundwater, and especially the transfer from surface to groundwater, were studied by combining hydrodynamics and isotopic tracers (18O, 2H). Monthly monitoring of groundwater level in around thirty wells was complemented by automatic recorders with hourly time steps since March 2016 in three wells, along a 600 m transect perpendicular to the wadi bed. The slow response of the water table is visible only two months after the first flood; its maximum rise was 1 m in 2016. Isotopic analyses of rainwater on a daily time scale, of the wadi water on a 1 h time scale during runoff and of groundwater (two complete campaigns in the dry and wet seasons and a specific monitoring of the transect every month) have provided additional information on surface-groundwater transfer
La nappe alluviale une ressource vulnérable en zone aride
No full textInternational audienceDans les zones arides la ressource en eau est essentiellement souterraine. L’expansion des agglomérations et le développement économique ont augmenté les besoins et de fait ces ressources sont de plus en plus sollicitées. C’est le cas de la région de Tamanrasset qui fait partie du Sahara algérien et qui compte 205 220 habitants. Dans la région d’étude, les formations géologiques sont cristallophyliennes et volcaniques. Localement, des nappes alluviales, liées aux écoulements superficiels, renferment des réserves dont la recharge est assurée par les crues de l’oued, c’est le cas de notre région d’étude où la nappe est alimentée par l’oued Tamanrasset. Cette recharge dépend des précipitations irrégulières tombant sur la région du Hoggar qui représentent une moyenne annuelle de 50mm à 1400m d’altitude (station de Tamanrasset) et 85mm à 2700m (station d’Assekrem). Dans de tels contextes, il est très important de mettre en évidence l’état et la variation du niveau de la nappe ainsi que les modalités de son écoulement et l’appréciation de sa qualité chimique. Pour atteindre cet objectif, un suivi mensuel de mesures piézométriques de l’aquifère alluvial de Tamanrasset a été réalisé depuis Novembre 2014. Les données des mesures piézométriques ont été utilisées pour établir des cartes piézométriques qui ont mis en évidence l’écoulement de la nappe et son évolution. Les paramètres physico-chimiques de la nappe ont été mesurés in-situ et des échantillons d’eau ont été prélevés au cours de la campagne de Novembre 2014. Les résultats obtenus montrent que la minéralisation de la nappe est relativement faible, la conductivité électrique oscille entre 283 et 936µS/cm, avec un pH variant entre 6,85 et 7,98. Les teneurs en bicarbonates présentent les plus fortes concentrations (jusqu'à 695,4mg/l) pour les anions et le sodium (jusqu'à 100,5mg/l) pour les cations. De même, les résultats des analyses montrent de fortes concentrations en nitrates qui atteignent 48mg/l. La minéralisation de la nappe est dans l’ensemble influencée par la géologie mais également par les activités humaines
