CFD modelling and simulation of drill cuttings transport efficiency in annular bends: Effect of particle sphericity

Abstract

Accurate prediction of the flow behaviour of drill cuttings carried by a non-Newtonian fluid in an annular geometry is important for the successful and efficient design, operation, and optimisation of drilling operations. Although it is widely recognised that practical drilling operations hardly involve perfectly spherical cuttings, the relative ease in mathematical description coupled with speedy computation are the main reasons for the prevalence of this simplifying assumption. The possibilities offered by the modification of the interphase exchange coefficient of the Syamlal-O'Brien model as well as its scarce implementation in literature have motivated the authors to delve into this area of research as far as the transport phenomena of non-spherical drill cuttings is concerned. Another aspect of this work was influenced by the need to understand the flow dynamics around bends (horizontal to inclined and inclined to vertical sections) during deviated drilling operations using two high viscosity muds (0.5% CMC and 0.5% CMC + 4% Bentonite mud). The Eulerian-Eulerian model was adopted for this study while considering particle sphericities of 0.5, 0.75 and 1 and diameters of 0.002 m, 0.003 m, 0.004 m, 0.005 m and 0.008 m respectively. It was discovered that particle deposition intensifies at the inclined-to-vertical bend compared to other locations in the flow domain. We also observe increased dispersion effects and transport velocities of non-spherical particles compared to particles of a perfectly spherical geometry. Furthermore, an improvement in the rheological properties of the drilling mud shows a remarkable increase in cuttings transport efficiency especially with the smaller particles. However, increased deposition of larger particles still poses a challenge to the wellbore cleaning process despite this rheological enhancement. The proposed CFD modelling methodology is thus capable of providing critical insight into the dynamics of cuttings transport, and the resulting computational observations are consistent with relevant experimental investigations.

Optimal rate allocation for production and injection wells in an oil and gas field for enhanced profitability

“…The present article adopts a simulation-based optimization method based on the approach proposed by Gunnerud, Foss and coworkers, in which the production network is broken down into several black boxes to formulate explicit relations, rather than treating the entire network as a single black box. 2,6 They argue that although proxy models are required for each section of the entire production network, configuring the optimizer to search using smaller simulators yields faster computations compared to searching over the entire production network. The surrogate modeling approach adopted here also offers a clear opportunity for implementation of a gradient-based optimization solver.…”

“…Local searching methods equipped with quadratic proxy models and many reasonable initial guesses are able to exploit smooth features of the objective function, and converge rapidly to a global optimum. The majority of the computational effort involved in solving problems with discrete variables can be attributed to the piecewise linearization procedure and the number of breakpoints required to capture nonlinear-ities in well and pipeline models 6. The absence of these variable types in our case studies significantly reduces the computational effort (as reflected inTable 7) compared to the MILP/MINLP studies.…”

Drill cuttings transport and deposition in complex annular geometries of deviated oil and gas wells: A multiphase flow analysis of positional variability

“…In this paper, we apply a physics-based multidimensional CFD approach for the elucidation of annular geometrical intricacies on the transport phenomena of drill cuttings. The work herein stems from the results of a previous analysis of ours that considers the effect of particle sphericity on cuttings transport (Epelle and Gerogiorgis, 2018b). The obtained results have been postprocessed in a different way (by extracting flow information from strategically positioned lines and planes in the annular domain, as well as considering threshold values) for better understanding of the cuttings transport phenomena.…”

PFEM–DEM for particle-laden flows with free surface

“…Such choices dene our method as a PFEM-DEM approach, hence a subcategory of the so-called CFD-DEM methods [67,52,53,55,54,61,62]. The CFD-DEM has been used directly in industrial problems such as uid catalytic cracker (FCC) units [49], pneumatic transport [50] and mud-ow transport problems from the oil industry [51]. But perhaps the most promising use of CFD-DEM procedures is in the derivation of empirical relations and validation examples [47,48], which can be used to improve the models used in coarser but more aordable techniques.…”