Ph.D. Tezi Görüntüleme | |||||||||||||||||||||
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| Summary: CUTTINGS TRANSPORT MODEL AND ITS ANALYSIS IN ANNULAR REGION BETWEEN TWO CYLINDERS
Karadeniz Technical University The Graduate School of Natural and Applied SciencesMathematics Graduate Program Supervisor: Prof. Dr. Erhan COŞKUN2011, 201 Pages, 3 Pages Appendices Efficient transportation of cuttings is very important for a good drilling process. Cuttings transport in an annular region is a complex problem as the transport is affected by many parameters. Predicting effective cuttings transport mechanism requires all of the parameters to be considered simultaneously. To better understand the cuttings transport mechanism, a mechanistic model is used for cuttings in Couette and Poiseuille flow, as well as the Helical flow being the superposition of Couette and Poiseuille flows (Papanastasiou, 2000). Cuttings residence time in suspension is the main focus of the study. Therefore, we consider the parameters affecting the cuttings transport such as viscosity, inner cylinder rotation speed, axial pressure gradient, particle mass, concentricity of cylinders and spacing between the cylinders, and try to determine the optimum combinations that lead to longer residence time in suspension, which is crucial for cuttings transport. Furthermore, under some assumptions, we obtain approximate analytical expressions for particle trajectories using two different approximate analytical techniques together. In addition to these, we determine the set of parameters that lead to vortices especially in eccentric setting and propose a set of parameters that avoids this turbulance regime.
Key Words: Cuttings Transport, Drilling Process, Laminar Flow, Couette Flow, Poiseuille Flow, Concentric Annulus, Eccentic Annulus, Newtonian Fluid, Non-Newtonian Fluid, Horizontal Well, Mechanistic Model, Differential Transform Method, Adomian Decomposition, Pade Approximation | |||||||||||||||||||||