Publications Scientifiques
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Item Modeling wax disappearance temperature using robust white-box machine learning(Elsevier Ltd, 2024) Nait Amar, Menad; Zeraibi, Noureddine; Benamara, Chahrazed; Djema, Hakim; Saifi, Redha; Gareche, MouradWax deposition is one of the major operational problems encountered in the upstream petroleum production system. The deposition of this undesirable scale can cause a variety of challenging problems. In order to avoid the latter, numerous parameters associated with the mechanism of wax deposition should be determined precisely. In this study, a new smart correlation was proposed for the accurate prediction of Wax disappearance temperature (WDT) using a robust explicit-based machine learning (ML) approach, namely gene expression programming (GEP). The correlation was developed using comprehensive experimental measurements. The obtained results revealed the promising degree of accuracy of the suggested GEP-based correlations. In this context, the newly-introduced correlations provided excellent statistical metrics (R2 = 0.9647 and AARD = 0.5963 %). Furthermore, performance of the developed correlation outperformed that of many existing approaches for predicting WDT. In addition, the trend analysis performed on the outcomes of the proposed GEP-based correlations divulged their physical validity and consistency. Lastly, the findings of this study provide a promising benefit, as the newly developed correlations can notably improve the adequate estimation of WDT, thus facilitating the simulation of wax deposition-related phenomena. In this context, the proposed correlations can supply the effective management of the production facilities and improvement of project economics since the provided correlation is a simple-to-use decision-making tool for production and chemical engineers engaged in the management of organic deposit-related issues.Item Rheological and flow behavior of water-in-oil Pickering emulsions stabilized with organo-hectorite clay(Elsevier, 2021) Boutheina, Merad; Bekkour, Karim; Pierre, François; Gareche, MouradThe rheological and flow behaviors of Pickering emulsions are studied as a function of their water concentration. The studied emulsions are water-in-gasoil inverse emulsions stabilized with organo-hectorite clay. An in-line emulsion preparation was performed and a novel emulsification system was used. The emulsification system was tested and confirmed before performing pipe-flow measurements. A stress-controlled rheometer was used to study the rheological behavior of organoclay stabilized inverse emulsions. It was found that the emulsions exhibited a shear thinning with yield stress non-Newtonian rheological behavior and that the flow curves were well correlated using the Herschel-Bulkley model. Pressure loss and axial velocity measurements were studied to investigate the pipe-flow behavior of the emulsions. Axial velocity of the fluids was measured using an Ultrasonic Pulsed Doppler Velocimeter. It was shown that, up to 50 wt% water mass concentration, an exponential increase of yield stress and viscosity values is noticed, and the phase inversion point is not reached. In the range of the applied flow rates, turbulence took place only in the case of the lowest water cut (0 wt%). The Herschel-Bulkley rheological parameters were used to simulate the pipe-flow behavior of the studied fluids, and showed a satisfactory correlation with the in-line measurements. Furthermore, wall shear stress and velocity profiles were used to study the short-, medium-, and long-term stability of the emulsionsItem Rheological study of concentrated dispersions. Application to the drilling fluid(Institute of Physics Publishing, 2018) Ouaer, Hocine; Gareche, Mourad; Allal, AhmedIn order to understand the rheological behavior of concentrated aqueous Algerian bentonite dispersions of drilling (sodium bentonite of Mostaganem "m'zila"), rheological tests were carried out. By varying the concentration of bentonite, flow tests have allowed to estimate the yield stress and apparent viscosity for each concentration and to see their influence on the rheological behavior of these dispersions. In addition dynamic tests (oscillatory) are used to define the linear region of our samples, the state of our fluid (elastic solid or viscous liquid) and understanding the mechanisms of structuring of the particles constituting the material. In parallel, other tests coupled with rheological measurements such as x-rays diffraction to know the mineralogical composition and granulometry to estimate the bentonite particle size.Item Rheological studies and optimization of Herschel–Bulkley parameters of an environmentally friendly drilling fluid using genetic algorithm(Springer, 2018) Ouaer, Hocine; Gareche, Mourad; Rooki, RezaThe Herschel–Bulkley rheological parameters of an environmentally friendly drilling fluid formulated based on an Algerianbentonite and two polymers—hydroxyethyl cellulose and polyethylene glycol—have been optimized using a genetic algorithm.The effect of hydroxyethyl cellulose, temperature, pH and sodium chloride (NaCl) on the three-parameter Herschel-Bulkleymodel was also studied. The genetic algorithm technique provided improved rheological parameter characterization compared tothe nonlinear regression, especially in the case of drilling fluids formulated with sodium chloride making it a better choice.Furthermore, the oscillatory test offered more reliable yield stress values. The rheological parameters were found to be verysensitive to different conditions. Yield stress and consistency index increased with increasing the hydroxyethyl cellulose con-centration, reaching maximum at a temperature of 65 °C and decreased with decreasing pH and also when adding sodiumchloride to the drilling fluid. The flow index changed inversely to yield stress and consistency index. The physical origins of thesechanges in rheological parameters were discussed and correlation between variation in rheological parameters and bentonitesuspension properties were concluded. Based on these results, it is recommended to use the proposed formulation of drilling fluidat high temperature and when the formation of alkaline pH is encountered due to the gelation mechanism and to select theoptimum concentration of NaCl to avoid degradation of the rheological parametersItem Thermal gelation of partially hydrolysed polyacrylamide/polyethylenimine mixtures using design of experiments approach(Elsevier, 2019) Ghriga, Mohammed Abdelfetah; Hasanzadeh, Mahdi; Gareche, Mourad; Lebouachera, Seif El Islam; Drouiche, Nadjib; Grassl, BrunoPolyethylenimine crosslinked polymer gels are gaining a huge interest in conformance control applications in oilfields. They are used to reduce the production of undesirable fluids (water & gas) by blocking the fractures that connect injection and production wells. In this paper, a statistical analysis on the thermal gelation of well characterized reactants namely partially hydrolysed polyacrylamide (PHPA) (Mw = 5.1 million Daltons and hydrolysis degree = 6%) and polyethylenimine (PEI) (Mw = 19.2 kilo Daltons and branching degree = 59%), was conducted using response surface methodology (RSM). A four factor doehlert matrix was employed in designing the experiments and evaluating the gelation time as function of salinity (0–8 g/L NaCl), polymer (PHPA) and crosslinker (PEI) concentrations, temperature (70 °C–90 °C) and their corresponding combinations. As a result, the gelation time was found to strongly vary with salinity, temperature and PHPA concentration following a nonlinear mathematical model. The analysis of variance (ANOVA) of this model revealed its significance in a 95% confidence level against experimental data. In a second part, an experimental investigation was carried out to understand the interaction between PHPA and PEI. To do so, the viscosity variations of analogue mixtures prepared with low molecular weight (Mw) polymers, such as polyacrylamide (PAM) and polyacrylic acid (PAA), were monitored using capillary viscometry at different conditions of temperature, pH and reaction time. The PAM/PEI mixtures showed a remarkable viscosity increase at typical pH of around 10 when cured at 80 °C. While, the PAA/PEI mixtures underwent precipitation at pH of around 6 revealing the strong interaction between PAA and PEI at this conditionItem Effect of non-ionic polymers on yield stress and kinetic structure of Algerian bentonite used in drilling fluids(2019) Ouaer, Hocine; Gareche, MouradItem Review of recent advances in polyethylenimine crosslinked polymer gels used for conformance control applications(Springer, 2019) Ghriga, Mohammed Abdelfetah; Grassl, Bruno; Gareche, Mourad; Khodja, Mohamed; Lebouachera, Seif El Islam; Andreu, Nathalie; Drouiche, NadjibItem Relationship between the fractal structure with the shear complex modulus of montmorillonite suspensions(Elsevier, 2016) Gareche, Mourad; Allal, A.; Zeraibi, Noureddine; Roby, F.; Azril, N.; Saoudi, L.Item Colloidal behavior of aqueous montmorillonite suspensions in the presence of non-ionic polymer(2015) Gareche, Mourad; Azri, N.; Allal, A.; Zeraibi, NoureddineIn this paper we characterized at first, the rheological behavior of the bentonite suspensions and the aqueous solutions of polyethylene oxide (PEO), then we were investigated the influence of this polymer in a water-based drilling fluid model (6% of bentonite suspension). The objective is to exhibit how the non ionic polymer with molecular weight 6×103 g/mol. of varying concentration mass (0.7%, 1%, 2% et 3%) significantly alter the rheological properties (yield stress, viscosity, loss and elastic modulus) of the bentonite suspensions. The rheological measurements made in simple shear and in dynamic on the mixture (water-bentonite-PEO), showed rheological properties of bentonite suspensions both in the presence and absence of non-ionic polymer. The PEO presents an affinity for the bentonite particles slowing down their kinetic aggregation. The analysis by X-rays diffraction also allowed understanding the structure of this mixture. It had revealed the intercalation between of the clay platelets on one hand, and the links bridges assured by the chains of polymer between bentonite particles beyond a critical concentration in PEO on the other hand. The Herschel- Bulkley rheological model is used for the correlation of our experimental resultsItem Numerical study of a thermodependent non-Newtonian fluid flow between vertical concentric cylinders(Elsevier, 2007) Zeraibi, Noureddine; Amoura, M.; Benzaou, A.; Gareche, MouradIn this paper, we present a numerical investigation of the thermal convection for a thermodependent non-Newtonian fluid in an annular space between two coaxial rotating cylinders. The rheological behaviour of the fluid can be expressed through the Ostwald-De-Waele power law: View the MathML sourceτ=Kγ˙n; all fluid properties except consistency index K are constant. K–T relation used is K = K0e−bT. The problem is studied when the heated inner cylinder is rotating around the common axis with constant angular velocity and the cooled outer cylinder is at the rest. The horizontal endplates are assumed adiabatic. The governing equations are solved using mixed finite elements method. The influence of the temperature on the structure of the dynamic and thermal fields is examined