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

Abstract

In this study, the two-fluid Eulerian-Eulerian multiphase flow model in ANSYS Fluent (v17.1) is adopted for the simulation of cuttings transport in a deviated annular geometry using two different non-Newtonian drilling fluids (described using the power law and Herschel-Bulkley models). The Syamlal-O'Brien interphase momentum exchange coefficient is implemented to capture non-spherical effects of the drill cuttings. The analysis conducted is based on the hypothesis that a position-dependent profile evaluation is expected to yield more insight into the transport process compared to a volume-averaged analysis over the entire flow domain. This is because the adopted simulation approach takes into account the microscopic particle properties which significantly affect the overall particle transport mechanism. However, this requires the application of robust postprocessing functionalities for data extraction from desired annular regions. Particle sizes considered are in the range of 0.002 m to 0.008 m with a sphericity range of 0.5 to 1.0. A rotational effect is incorporated in our model to describe the drillpipe motion in an annular wellbore with a vertical eccentricity of 0.6. The considered geometry contains a vertical, inclined and horizontal section with interconnecting upper and lower bends. The analysis of the particle velocity and concentration profiles revealed that the mud rheology, particle sphericity and particle sizes play vital roles in determining the cuttings removal process. It is particularly observed that the lower annular region of upper bend, is most susceptible to particle deposition with the lowest transport velocities observed. Our positional variability analysis has shown that the alternating dominance of nonspherical and spherical particles' velocities significantly depends on the nature of the flow (i.e. dense granular flow or dilute annular flow in the upper and lower sections respectively).

Treatment of oil-based drilling cuttings by floatation-advanced oxidation two-step process

“…During the drilling stage of shale gas exploration, the high clay content of shale layers is easily able to cause drilling accidents when swelling with water occurs 1–3 . Therefore, oil-based drilling mud is widely used to protect the well wall when drilling in shale layers, and large amounts of oil-based drilling cuttings (OBDC) are inevitably generated.…”

A CFD Validation Effect of YP/PV from Laboratory-Formulated SBMDIF for Productive Transport Load to the Surface

“…Muds and cuttings transport phenomena occur through their respective drilling [10] and the annular column of the drilling system, factoring in the position of the drilling pipe at the time of rotation. However, previous studies over the years dived into the concentric and eccentric [11][12][13] effects of drilling pipes and their capacity to lift cuttings to the surface; while other research experimented [14][15][16][17][18], a few considered optimizing these effects with computational analysis [19][20][21][22][23][24][25][26][27][28][29][30]. Nonetheless, T.N.…”

Effect of eccentricity and inner pipe motion on flow instability for flow through annulus

“…Amanna and Movaghar [1] have studied the cutting transport behaviour for the directional drilling cases. Epelle and Gerogioris [7,8] have simulated the cutting transport in the annular bends and complex shapes. This results in the emphasis that the cost of drilling operations may run into billion dollars of capital investments.…”