On particle transport and turbulence in wellbore flows of non-Newtonian fluids - Findings from a cuttings transport process analysis by means of computational fluid dynamics, rheometry, and dimensional analysis
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Cuttings transport modeling was analyzed with a major focus on three dimensional (3D) Computational Fluid Dynamics (CFD) approaches including rheometry and to a lesser extent on one-dimensional modeling and dimensional analysis. As a first step, the relevant parameter space was analyzed and field values typical for the Norwegian Continental Shelf were established. Dimensional Analysis was applied to further understand the parameter space and to establish a process description based on a polynomial. For the fluid phase (i.e., the drilling fluid or a drilling fluid model system), the classical General Newtonian Fluid (GNF) concept was investigated by means of rheometry and the example of polymeric solutions (Polyanionic Cellulose (PAC) dissolved in distilled water) typically used in experimental cuttings transport studies. It is shown that the GNF assumption only holds if the fluid is at steady-state with respect to its microstructure and that such a steady-state may be hard to achieve in experimental works because of the long rheological timescales of the fluid. Concerning the solid phase (i.e., the cuttings), the performance of the typical modeling concept utilized in cuttings transport research, namely the Kinetic Theory of Granular Flow (KTGF) in combination with a frictional viscosity model accounting for dense granular regions, was evaluated by means of CFD simulations of the cliff collapse problem. Several fluids (air, water, two PAC solutions) and spatial scales (cliff height and particle diameter), among other parameters such as the cliff’s aspect ratio and initial solid volume fraction were investigated. While the typical sloped deposits were obtained in most cases shortly after the collapse these were found to be unstable: The top layer of the sediment bed continues flowing after the collapse which eventually leads to an entirely flat deposit. This is attributed to the utilized modeling approach which is not capable of handling the top sediment bed layer successfully. As an alternative, a modeling approach prominent in the field of environmental sediment transport modeling was tested. The dense region is dynamically excluded from the computational domain, and the Exner equation is used to describe the evolution of the sediment bed. Problems such as proper closures for the bed load transport models as well as contact problems were encountered, disqualifying this approach for use of cuttings transport simulations within the scope of this project. The relevance and magnitude of turbulence and dunes in wellbore flows were estimated and several pipe and annular single-phase RANS simulations were compared with DNS data (generated in the AdWell project) for Newtonian and shear-thinning fluids. While wellbore flows are laminar to transitional (mostly depending on the fluids’ viscosity), none of the turbulence models investigated appears to be universally applicable. However, this part is still in progress and only preliminary conclusions are presented. A subproblem of cuttings transport, a particle subjected to a cross-flow of a mildly viscoelastic, shear-thinning fluid, was investigated by means of CFD. The particle is treated in a Lagrangian manner and the particle-induced shear is accounted for in the computation of the fluids viscosity as seen by the particle. Several cases were investigated and the model was validated with results from the literature. Discrepancies are found close to the lower channel wall were the particles in the experiments are advected much farther than in the simulations. Finally, drill pipe rotation in combination with orbital drill pipe motion was investigated. Specifically, the effect of forward, i.e., synchronous, and backward, i.e., asynchronous, whirl (SW and AW, respectively) on cuttings transport was evaluated and compared with classical concentric and eccentric arrangements. AW and, more dramatically, SW improve cuttings transport, albeit depending on other system parameters such as the fluid’s rheological parameters and the drill pipe’s rotational rate. However, for the parameter space investigated, best transport of cuttings was obtained in a positively eccentric drill pipe system because the main flow occurs at the top of the bed and consequently high shear stresses acting on the bed. This thesis highlights current shortcomings and potential for improvement of CFD cuttings transport simulation. Further work is required on all individual topics to achieve better quantitative results and to integrate subscale models into a model on the annular scale. The findings presented here will hopefully contribute to a more comprehensive understanding of cuttings transport and support further development of CFD models applicable to the annular scale and more coarse, real-time models applicable to the entire wellbore.
Består avPaper 1: Busch, Alexander; Islam, Aminul; Martins, Dwayne Werner; Iversen, Fionn; Khatibi, Milad; Johansen, Stein Tore; Time, Rune Wiggo; Meese, Ernst A. Cuttings-transport modeling-part 1: Specification of benchmark parameters with a norwegian-continental-shelf perspective. SPE Drilling & Completion 2018 ;Volum 33.(2) s. 130-148 Not included due to copyright restrictions. Available at https://doi.org/10.2118/180007-PA
Journal paper 2: Busch, Alexander; Werner, Benjamin; Johansen, Stein Tore. Cuttings Transport Modeling—Part 2: Dimensional Analysis and Scaling. SPE Drilling & Completion. SPE Drilling & Completion 2019. Not included due to copyright restrictions. Available at https://doi.org/10.2118/198907-PA
Journal paper 3: Busch, Alexander; Myrseth, Velaug; Khatibi, Milad; Skjetne, Paal; Hovda, Sigve; Johansen, Stein Tore. Rheological characterization of Polyanionic Cellulose solutions with application to drilling fluids and cuttings transport modeling. Applied Rheology 2018 ;Volum 28.(2) s. 1-16 (CC BY)
Journal paper 4: Busch, Alexander; Johansen, Stein Tore. On the validity of the two-fluid-KTGF approach for dense gravity-driven granular flows as implemented in ANSYS Fluent R17.2 Powder Technology, Vol. 364, Special Issue CPT-2018-Melbourne, 2020.
Journal paper 5: Busch, Alexander; Johansen, Stein Tore. An Eulerian-Lagrangian CFD study of a particle settling in an orthogonal shear flow of a shear-thinning, mildly viscoelastic fluid. Journal of Non-Newtonian Fluid Mechanics 2019 ;Volum 263. s. 77-103
Journal paper 6: Busch, Alexander; Johansen, Stein Tore. Cuttings transport: On the coupled effect of drillpipe rotation and lateral motion on the cuttings bed. Journal of Petroleum Science and Engineering. Final version available at https://doi.org/10.1016/j.petrol.2020.107136
Conference paper 1: Busch, Alexander; Khatibi, Milad; Johansen, Stein Tore; Time, Rune Wiggo. A 2D sediment bed morphodynamics model for turbulent, non-Newtonian, particle-loaded flows. I: Progress in Applied CFD – CFD2017 Selected papers from 12th International Conference on Computational Fluid Dynamics in the Oil & Gas, Metallurgical and Process Industries. SINTEF akademisk forlag 2017 ISBN 978-82-536-1544-8. s. 479-489
Manuscript 1: Busch, Alexander; Simonsen, Are; Johansen, Stein Tore. DNS vs. RANS turbulence modeling of turbulent pipe and annular flows of shear-thinning fluids
Journal paper 7: Aarsnes, Ulf Jakob Flø; Busch, Alexander. Transient modeling of one-dimensional solid-liquid flow in conduits. International Journal of Multiphase Flow 2018 ;Volum 105. s. 102-111
Conference paper 2: Zoric, Josip; Busch, Alexander; Meese, Ernst A.; Khatibi, Milad; Time, Rune Wiggo; Johansen, Stein Tore; Rabenjafimanantsoa, Herimonja Andrianifaliana. On Pragmatism in industrial modeling - Part II: Workflows and associated data and metadata. Eleventh International Conference on CFD in the Minerals and Process Industries CSIRO. Not included due to copyright restrictions. Available at http://www.cfd.com.au/cfd_conf15/PDFs/032JOH.pdf
Conference paper 3: Khatibi, Milad; Time, Rune Wiggo; Busch, Alexander; Johansen, Stein Tore; Martins, Dwayne Werner; Islam, Md. Aminul; Iversen, Fionn. Investigation of Suspended Particles Around an Obstacle in Vertical Pipe Flow: Comparison Study Experimental and Simulation. I: ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering - Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology, Trondheim, Norway, June 25–30, 2017. ASME Press 2017 ISBN 978-0-7918-5776-2. s. - Not included due to copyright restrictions. Available at https://doi.org/10.1115/OMAE2017-62244
Conference paper 4: Busch, Alexander; Johansen, Stein Tore. Judging the Generalized Newtonian Fluid assumption for cuttings transport modelling by applying time scale comparisons. The Transactions of the Nordic Rheology Society, Vol. 24., pp. , 2018. Not included due to copyright restrictions.
Manuscript 2: Busch, Alexander; Johansen, Stein Tore. Estimating the level of turbulence and dunes in wellbore flows by means of bulk flow quantities. AdWell project report.
Manuscript 3: Busch, Alexander. Conversion of engineering oil field rheological model parameters to SI model parameters. Personal memo.