The article presents the results of laboratory studies on active acoustic and deformation monitoring of hydraulic fracturing crack opening in a model porous material based on gypsum. For comparison, the results of numerical modeling of the attenuation of elastic waves when passing through a model sample, based on the obtained experimental data, are presented. The work directly measures the fracture opening in comparison with the change in the amplitude of the ultrasonic pulse passing through the fracture during its formation and opening. The model sample has a cylindrical shape, and there is a tube with seedings inside the model to the middle of the sample's height to create a hydraulic fracturing crack up. The sample is placed between two aluminum disks, on the surface of which piezoelectric converters are mounted, that operate in the receiver and transmitter mode. With the help of a pumping system, hydraulic fracturing fluid (silicone oil) is injected into the sample through a tube, which leads to the formation of a circular crack perpendicular to the axis of the sample. As the fluid flow rate increased, the crack opening value was measured using induction displacement meters. According to the results of the study, dependences were constructed linking the injection pressure of the hydraulic fracturing fluid and the magnitude of the fracture crack opening with the magnitude of the amplitude of the signal of ultrasonic pulses that passed through the crack. The numerical simulation has shown that the results of the estimated normalized amplitudes of the ultrasonic pulse, depending on the size of the crack opening, differ from the experimental results with an error of up to 7%. The obtained results of the study allow us to estimate the magnitude of the hydraulic fracturing crack opening using active acoustic monitoring.
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