Publications Scientifiques
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Item Numerical and experimental investigation of hydraulic fracture using the synthesized PMMA(Springer, 2021) Khadraoui, Sofiane; Hachemi, Messaoud; Allal, Ahmed; Rabiei, Minou; Arabi, Abderraouf; Khodja, Mohamed; Lebouachera, Seif El Islam; Drouiche, NadjibHydraulic fracturing is a technique used for stimulation of unconventional reservoirs including shale plays. Several parameters, including rock properties, state of stresses, and fracturing fluid characteristics, influence successful design and implementation of a hydraulic fracturing operation. Monitoring of real-time hydraulic fracture initiation and propagation in the field to improve the design parameters is costly. Several hydraulic fracturing laboratory studies have been reported; however, similar to the field operations, real-time observation of the fracturing fluid penetration to the rock sample is not practical throughout the test but the sample can only be inspected post-experiment. In this work, we present the specifications of a through see synthesized polymethyl methacrylate (PMMA) material which was made for the purpose of laboratory experimental hydraulic fracturing testing. The mechanical testing of the PMMA allowed us to obtain the mechanical properties, including tensile and compressive strengths as well as toughness are close to the typical tight samples used in the laboratory for hydraulic fracturing experiments. Hydraulic fracturing tests were performed on a number of cylindrical PMMA samples to investigate the effect of injecting fluid viscosity and flow rate as well as the geometry of the initial crack on fracture breakdown pressure and the characteristics of the propagating fracture. The ability to directly observe the fracture geometry throughout the experiment allowed us to make a good correspondence between the pressure–time curve and the evolution of the fracture geometry. Numerical modeling using ANSYS was performed to run multiple simulations and do sensitivity analysis of different parameters similar to the laboratory experiments. The results also were compared with some of the analytical solutionsItem 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 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, Nadjib