FILTRATION WAVE MOVEMENT ALONG THE NON-COHESIVE SURFACE OF A POROUS BODY

Abstract

Link for citation: Tairova A.A., Belyakov G.V., Iudochkin N.A. Filtration wave movement along the non-cohesive surface of a porous body. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 6, рр.20-26. In Rus. The relevance of the research is caused by the need to study the mechanisms of interaction of the filtration flow with fractured rock and changes in its mechanical parameters when opening large oil-removing surfaces, which are the walls of a hydraulic fracture. With the development of a crack, repacking or destruction of the particles of the skeleton occurs, which can lead to decrease in resulting surface permeability, as well as to the change in crack direction. The main aim of this study is to visualize the distribution of the filtration front along the non-cohesive surface of a porous body and the change in the stress-strain state of the skeleton on a physical model. Object: poroelastic rocks of an oil-bearing formation. Methods: laboratory studies to determine the rate of propagation of the «crack» tip as a result of filtration of a viscous liquid at various pressure drops and stress-strain states of the skeleton. Results. A visual picture of viscous fluid interaction with a poroelastic skeleton was obtained for various parameters of the porous medium and injection pressure. The authors have proposed the analytical dependence for the presented model, showing that the relative width of the «crack» depends on the elastic parameters and the initial size of the porous mass, the pressure of the injected fluid, and its coefficient of friction against the «bottom» and «roof». The results of the experiments showed that the opening of closed non-cohesive surfaces of porous mass, simulating a crack, is unstable. The rate of propagation of the «fracture» tip depends on the angle of its opening. During the course, it was noticed that when the «crack» opens, the mass immediately behind the walls is compressed, as a result of which the permeability of the skeleton decreases. Thus, all the liquid rushes to the tip, thereby increasing the length of the «fracture».

Keywords

• stress-strain state
• porous medium
• fluid filtration
• crack tip
• filtration front
• medium elasticity