Showing papers by "Sonatrach published in 2016"

A Rheological Study of Xanthan Polymer for Enhanced Oil Recovery

Abstract: This study explored the potential application of xanthan gum as a polymer-flooding agent for oil recovery applications in a specific Devonian oil field. Rheological measurements using oscillatory and steady shear were carried out to examine the change in shear viscosity when the polymer was applied under reservoir conditions. The xanthan rheological properties were described by the Herschel–Bulkley and Ostwald models to characterize its non-Newtonian behavior. As expected, the results showed that higher xanthan concentrations raised the polymer viscosity and increased the degree of shear thinning. Addition of alkalis caused the viscosity of the xanthan solutions to decrease, but they maintained their shear-thinning properties. Polymer solutions in typical oil field brine increased in viscosity by ca. 400% for 720 hours storage time. On the other hand, as expected, the solutions lost their viscosity gradually with increasing temperature. However, at reservoir temperature (68°C), the polymer solutio...

Constraining burial history and petroleum charge in exhumed basins: New insights from the Illizi Basin, Algeria

Abstract: Intracratonic sag basins commonly have relatively simple tectonic histories; however, later tectonic activity involving exhumation can make reconstructing the burial history a challenging task. This is important because the relative timing of hydrocarbon generation and trap formation can be a key factor in risk assessment. If trap formation postdates peak hydrocarbon generation, exploration plays are typically downgraded. Mechanisms for charge in such exhumed basins are critical factors for understanding exploration risk. This study uses data collected from an Ordovician gas-condensate field in the Illizi Basin of Algeria to document the charging of a trap formed, or modified, during exhumation of the basin following maximum burial. Integrated analysis of sonic compaction data, thermal history indicators, and stratigraphic well data was used to constrain the burial and thermal history of the region. Hydrocarbon generation in the lower Silurian source rock is interpreted to have occurred during the Carboniferous (prior to Hercynian exhumation) and during the Late Cretaceous–early Eocene maximum burial (prior to Eocene exhumation). Structural reconstructions indicate that the field was initially located on the southern flank of a long-lived, intrabasinal, Paleozoic paleohigh. The large, low-relief structural closure that defines the present-day accumulation formed as a result of northward tilting of the Illizi Basin during Eocene uplift of the Hoggar massif. The study demonstrates that the timing of trap formation at the Ordovician field postdates the main local hydrocarbon generation events within the basin, suggesting that alternative hydrocarbon charge mechanisms are required. This study indicates considerable potential to charge updip traps on the flanks of exhumed petroliferous basins via redistribution of the preexisting hydrocarbons within the basin.

Coupling stratigraphic and petroleum system modeling tools in complex tectonic domains: case study in the North Algerian Offshore

Abstract: In the eastern Algerian offshore basin, 3D basin modeling applied for facies prediction and petroleum potential assessment shows that most favorable zones for reservoir development and hydrocarbon occurrence are located at a maximum distance of 60 km from the coastline. The lack of well data in this area is partly compensated by a large data set of geophysical and geological (GG they represent important constraints for 3D dynamic modeling. Facies distribution model is constrained by sequence and environment evolution through time that is defined from onshore outcrops. 2D structural reconstitution and thermal modeling were also undertaken with ArcTem software. The structural interpretations highlight the occurrence of north-verging ramps during the Quaternary which played an important role in HC generation and migration. Three source rocks have been considered for maturation modeling with Temis Flow software, Burdigalian, Langhian, and Tortonian. They are found to be in gas window in the deep areas and locally in oil window at shallower structured zones. The modeling results indicate that the main fluid discharge was focused toward the southern border of the offshore basin where recent thrust faults (parallel to the margin) are located. In order to test the role of these faults in terms of hydrocarbon migration and trapping, two scenarios are considered according to whether they were sealed or not. In both cases, the 2D/3D simulations depict overpressures (2,000–4,000 psi) in the pre-salt sedimentary package. However, the hydrocarbon charge is most efficient with the sealing faults for the lower Langhian and lower Messinian reservoirs. The hydrocarbon potential depends mostly on the lateral extension of seals, their sealing capacity and the organic carbon (TOC) content of potential source rocks. Besides, the sea drop of about 1,000 m during the Messinian salinity crisis has induced depressurization that caused oil and gas seepage from Miocene reservoirs.

Performance of a Photovoltaic Pumping System Driven by a Single Phase Induction Motor Connected to a Photovoltaic Generator

Abstract: Solar energy is one of the most widely used renewable sources in the world. This explains the interest shown by researchers on the improvement of the quality and performances of this renewable source. The availability of low-cost solar cells increases the interest and needs in photovoltaic (PV) system applications following standard of living improvements. Nowadays, water pumping systems powered by solar-cell generators are one of the most important applications. In fact three phase induction motor fed by PVG is well known in literature, while the single phase induction motor for low power application used widely in domestic utility has never been investigated. In this paper the performances of a single phase induction motor (SPIM) connected to a photovoltaic generator (PVG) through an inverter are analyzed. Firstly, the mathematical model of the suggested structure is developed. Secondly, the concept of the Indirect Rotor-Field-Oriented Control (IRFOC) techniques is used to pilot the working of the single phase induction motor coupled with the centrifugal pump. Then, the chosen maximum power point tracking algorithm MPPT adjust pump operation to meet the desired water flow and pressure conditions. The proposed approach has the advantage no use the DC/DC converter, reduced size, low cost. This results in much higher overall system operating efficiencies. Finally, Simulation results show the effectiveness and feasibility of the suggested approach.

Proposal for an Evaluation Method for the Performance of Work Procedures

Abstract: Background Noncompliance of operators with work procedures is a recurrent problem. This human behavior has been said to be situational and studied by many different approaches (ergonomic and others), which consider the noncompliance with work procedures to be obvious and seek to analyze its causes as well as consequences. Methods The object of the proposed method is to solve this problem by focusing on the performance of work procedures and ensuring improved performance on a continuous basis. Results This study has multiple results: (1) assessment of the work procedures' performance by a multicriteria approach; (2) the use of a continuous improvement approach as a framework for the sustainability of the assessment method of work procedures' performance; and (3) adaptation of the Stop-Card as a facilitator support for continuous improvement of work procedures. Conclusion The proposed method emphasizes to put in value the inputs of continuous improvement of the work procedures in relation with the conventional approaches which adopt the obvious evidence of the noncompliance to the working procedures and seek to analyze the cause–effect relationships related to this unacceptable phenomenon, especially in strategic industry.

First application of the cop method to vulnerability mapping in the meffrouch catchment

Abstract: This paper presents the first application of the COP method for the vulnerability mapping in Mefrouch catchment (Tlemcen, Algeria). This method has been developed for the intrinsic vulnerability of carbonates aquifers in the frame of the European COST action 620( Zwahlen 2004 ). It takes into account three factors: the concentration of flow (C factor), the overlaying layers above the water table (O factor) and the precipitation (P factor). Since the method is intended for the karstic medias, it takes into account karst specific characteristics such as swallow holes and sinking streams. The vulnerability map established in this work shows that Meffrouch catchment is composed of five vulnerability classes. The method classifies 27% of the total area of the catchment as zones of high to very high vulnerability. This percentage reveals that anthropic actions can seriously affect the groundwater of the region. In order to prevent pollutants from reaching this vital resource, the established map can be used for the delineation of zones to be protected.

Negotiation model for knowledge management system using computational collective intelligence and ontology-based reasoning: case study of SONATRACH AVAL

Abstract: This paper presents an agent-based approach that facilitates knowledge management and decision making in maintenance field by enabling the collaboration and negotiation between experts in SONATRACH AVAL. The main objective of the suggested model is to treat the business rules with semantic errors, expert agents are asked to negotiate in order to accept or refuse a modification of rules. To do so, the expert manager can be represented by an intelligent agent that negotiates with experts (participants). We propose an interactive negotiation model utilising an extended version of the contract net protocol (CNP) and an ontology named OntoloG. The experimental results show that the developed computation collective intelligence approach is very interesting and efficient for expert collaboration in the well-known petroleum enterprise in Algeria (SONATRACH).