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The article relevance is caused by the critical estimation of the data presented in domestic and foreign publications on problems related to modeling of viscous fluid streams while interacting with particles of a dispersed material and with walls of the devices intended for performance of drilling operations; clearing of wellbores from cuttings taking into account well inclination and drillpipe eccentricity. The main aim is to introduce the bibliographic analysis of hole cleaning and cuttings transport, focused on finding ways to efficiently increase operational efficiency; to work out approaches and methods to model the cuttings transport in vertical and horizontal holes; to explain modern data on numerical modeling of cuttings transport problems; to provide recommendations to increase hole cleaning efficiency. The research methods are theoretical and practical ones, characterizing fluid flow in systems, containing particles and the legitimacy of idealization of transport phenomena in mixtures; as well as the methods borrowed from other disciplines aimed at calculating the influence of flow regime and drillpipe rotation and eccentricity on location and behavior of dispersed particles. The general concepts of hydrodynamic and heat- and mass transfer principles in rheological complex media are not discussed in detail, and explained only to that degree which is required for clarity and completeness. The experimental material contains data on applicability of the theory to real physical systems. Most investigations are based on analyzing particle movement through fluid in common lumps as it originates at sedimentation as well as when particles remain more or less motionless, as in densely packed beds; or the relative motion of particles and fluid with complex turbulent distribution; at motion of particles relative to each other when the flow of the carrying medium is a complex shear flow. Results. The paper introduces the analysis of experimental and theoretical results, important for applications related to cuttings transport phenomena, and the features accompanying processes of momentum, mass and energy during the flow of rheologically complex homogeneous and heterogeneous viscous mixtures in the annular space between a rotating eccentric inner pipe and a non-rotating outer pipe. Cuttings accumulation and difficulties in its transportation have major real world applications in drilling inclined and horizontal wellbores. Modeling results and the existing empirical relationships for cuttings behavior are critically analyzed. Advantages and the legitimacy of assumptions of some turbulent models and their closing relationships and dynamic, diffusive properties are presented. Also the parameters and mechanisms modeling the formation, accumulation, sedimentation, transport and separation of slime cuttings from a liquid in which they are suspended are given. The last 25–30 years have seen the numerous advances in numerical methods of multi-parameter and multidimensional modeling of hydrodynamics in dispersed mixtures (suspension, foam, powders). The analysis of experimental works shows that observation of dynamics of solid and liquid particles interaction by contactless means of registration can provide valuable information for validation and verification of the modern Reynolds Shear Stresses (RSS)-models of turbulence and specific turbulent fluxes for streams based on kL-, ke-equations, capable to predict complex turbulent flow of a mixture. The paper introduces the prospects of developing a universal algorithm with the possibility of a detailed prediction of effects: cutting bed formations in arbitrary points of annular spaces; determination of the minimum speed necessary for its formation and removal. The latter can be used in further research for determination of maximum admissible Rate Of Penetration (ROP); optimum values pump output; establishing field guidelines on duration and sequence of well cleaning operations, and the frequency of tripping operations.

izvestiâ tomskogo politehničeskogo universiteta. inžiniring georesursov

ПРОЦЕССЫ ТРАНСПОРТА ШЛАМА ПРИ ОЧИСТКЕ СКВАЖИН С ПРОИЗВОЛЬНОЙ ОРИЕНТАЦИЕЙ БУРОВЫХ ТРУБ, СОДЕРЖАЩИХ ЭКСЦЕНТРИЧНО РАСПОЛОЖЕННОЕ КРУГЛОЕ ЯДРО С ПОДВИЖНОЙ СТЕНКОЙ: ПРОБЛЕМЫ, РЕЗУЛЬТАТЫ, ПЕРСПЕКТИВЫ (ОБЗОР)