Browsing by Author "Allal, Ahmed"

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    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, Nadjib
    Hydraulic 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 solutions
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    Rheological study of concentrated dispersions. Application to the drilling fluid
    (Institute of Physics Publishing, 2018) Ouaer, Hocine; Gareche, Mourad; Allal, Ahmed
    In 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.