Analysis of Yield-Power-Law Fluid Flow in Irregular Eccentric Annuli

Hussain, Quazi E.; Sharif, M. A. R.

doi:10.1115/1.2795036

Cited by 22 publications

(6 citation statements)

References 15 publications

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“…Overcoming these setbacks, Mitsoulis et al proposed a new HB stress function based on Papanastasiou idea on Bingham type materials for a large but finite apparent viscosity value at vanishing shear rate as

\overset{true‾}{\overset{τ}{true}} = (K | \dot{γ} |^{n - 1} + τ_{0} \frac{1 - \exp (- m | \dot{γ} |)}{| \dot{γ} |}) \overset{true‾}{\overset{\dot{γ}}{true}},

where the regularization parameter m is a large number to guarantee large apparent viscosity at vanishing rate‐of‐strain at a value of

m τ_{0} + K | \dot{γ} |^{(n - 1)})

. This model has been implemented in various numerical modelling for HB fluids …”

Section: Introductionmentioning

confidence: 99%

Modified Yield Power‐Law fluid flow in narrow annuli with inner rotating pipe

et al. 2014

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A proposed viscosity model for Yield Power‐Law fluid by Souza Mendes and Dutra (SMD), devoid of discontinuities at vanishing shear rate, is adopted in a 3D CFD simulation study. Radial distributions of axial, tangential, and coupled components of velocities are measured along concentric and eccentric narrow annuli. The flow is assumed to be fully‐developed, laminar, and steady state. Several parameters such as diameter ratios, eccentricities, and inner pipe angular speeds were varied to analyze their influence on the flow distributions and annular pressure losses. The simulated results of radial distributions of axial and tangential velocities show good agreement with experimental data and analytic solutions from previous studies. Annular flow instabilities in the form of Taylor vortices in the flow fields are briefly discussed. This study shows how reliable CFD simulations can replicate the actual, yet complex, oil and gas drilling operations.

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\overset{true‾}{\overset{τ}{true}} = (K | \dot{γ} |^{n - 1} + τ_{0} \frac{1 - \exp (- m | \dot{γ} |)}{| \dot{γ} |}) \overset{true‾}{\overset{\dot{γ}}{true}},

where the regularization parameter m is a large number to guarantee large apparent viscosity at vanishing rate‐of‐strain at a value of

m τ_{0} + K | \dot{γ} |^{(n - 1)})

. This model has been implemented in various numerical modelling for HB fluids …”

Section: Introductionmentioning

confidence: 99%

Modified Yield Power‐Law fluid flow in narrow annuli with inner rotating pipe

et al. 2014

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“…The flow stagnation problem is directly associated with high eccentricity in highly deviated wells and typically occurs in the small gap width between the coiled tubing and the casing (Figures 1 and 2). This phenomenon has been thoroughly explained by several researchers, including Haciislamoglu and Langlinais (1990), Chin (1992), Azouz et al (1993), Hussain and Sharif (1998), Escudier et al (2002), Ogugbue and Shah (2011), and Asafa and Shah (2012). Without agitation induced by pipe rotation, pipe reciprocation, and turbulent flow, solid beds continually build up along the wellbore.…”

Section: Introductionmentioning

confidence: 88%

Improving Post-Stimulation Coiled Tubing Drillout

Asafa

Williams

González

et al. 2014

Day 1 Tue, March 25, 2014

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In the last few decades, coiled tubing has been widely employed for post-stimulation drillout of composite or cast-iron bridge plugs and isolation sleeves used in multi-stage hydraulic fracture stimulation in horizontal wells. Due to its inherent capability of continual deployment, coiled tubing technology has increased in popularity for this application over conventional jointed-pipe snubbing with rig-assist snubbing units. Despite the increasing use of coiled tubing units, drillout practices have typically been based on "art" rather than science, often resulting in drilling problems such as poor fluid efficiency and hole cleaning issues, lost circulation, stuck pipe, lost-in-hole tools, and parted pipe. Unfortunately, a greater percentage of stuck pipe incidents are directly related to poor hole cleaning, and it is not surprising that the causes of these problems are often not well understood. Thus, various approaches have been utilized to prevent recurrence based on incorrect assumptions. While some of these problems have been adequately dealt with in several publications, the determination of optimum fluid properties for efficient hole cleaning as well as the effectiveness of short tripping have been given minimal attention. To a large extent, fresh water, or brine, is mixed with various additives such as friction reducer for pressure loss and pipe friction, hydrogen sulfide scavenger and inhibitor, biocide, scale inhibitor, and polymer gel while drilling plugs. A common hole cleaning practice is the use of intermittent high-viscosity gel sweeps, wiper tripping to kick-off point after drilling a predefined number of plugs, and flowing back the well in an underbalanced condition while drilling and short tripping. The effectiveness of these practices is worth questioning based on the occasional drag and stuck pipe encountered while tripping out of hole. This paper addresses the misconceptions related to coiled tubing hydraulics and hole cleaning, as well as reviews the common drillout practices and their cost implications including coiled tubing rig up, coil size selection, bottomhole assembly, fluids efficiency, and short tripping. Various best practices are recommended for improving post-stimulation drillout, with specific emphasis on how to minimize drillout cost.

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“…Similar behavior was observed for nonrotating inner cylinder in an earlier Ž . work of Hussain and Sharif 1998 . The presence of a secondary flow in the wider part of the eccentric annulus is evident from the streamline plots using the u and ® velocity components only.…”

Section: Eccentric Annulusmentioning

confidence: 97%