Analysis of the Effect of Eccentricity on the Flow Characteristics of Annular 
Flow of Non-Newtonian Fluids Using Finite-Element Method

Özbayoğlu, A. Murat; Omurlu, Cigdem

doi:10.2523/100147-ms

Cited by 5 publications

(6 citation statements)

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“…For example, for an eccentric annulus, frictional pressure loss will decrease as the pipe eccentricity increases, if all other parameters are kept constant 13 . For a realistic modeling approach, those variables which have minor or major effect on cuttings transport should be taken under consideration.…”

Section: Theorymentioning

confidence: 99%

“…Thus, cuttings bed area for inclinations from 60-90 degrees can be estimated as; (13) When the signs of the equation constants serving for each dimensionless group in equation-13 are analyzed, the constants seem to be physically making sense. In order to increase the accuracy of the empirical correlations, the dimensionless groups are normalized, and carried on a similar order of magnitude.…”

Section: Empirical Correlationsmentioning

confidence: 99%

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Effect of Pipe Rotation on Hole Cleaning for Water-Based Drilling Fluids in Horizontal and Deviated Wells

Özbayoğlu

Saasen

Sorgun³

et al. 2008

All Days

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One of the major concerns during drilling horizontal and directional wells is proper hole cleaning. If there exists a stationary bed, generally, an increase in the fluid velocity will erode the bed significantly. However, depending on the drilling conditions, very high fluid velocities are needed for bed removal, which may not be applied due to hydraulic and physical limitations. In such cases, pipe rotation may enhance the cuttings transport mechanically, and effective hole cleaning can be achieved even at fluid velocities lower than the critical annular fluid velocities required to prevent stationary bed development. In this study, the effect of pipe rotation on hole cleaning is investigated for horizontal and directional wells. Cuttings transport experiments have been conducted at METU Cuttings Transport Flow Loop using pure water as well as water-based muds consist of different concentrations of xanthan biopolimer, starch, KCl and soda ash, weighted with barite. Effect of pipe rotation have been observed for hole inclinations from horizontal to 50 degrees, for rate of penetrations from 15 to 45 ft/hr, for flow velocities from 2.1 ft/s to 7.2 ft/s, and for pipe rotations from 0 to 120 rpm. Pressure drop within the test section, and stationary and/or moving bed thickness are recorded besides the other test conditions. It has been observed that, pipe rotation has a significant improvement on cuttings transport, especially if the pipe is making an orbital motion. Also, pipe rotation drastically decreases the critical fluid velocity required to remove the stationary cuttings bed totally. However, after a certain rotation speed, no additional contribution of pipe rotation on hole cleaning is observed. When there are no cuttings present, the frictional pressure losses are increasing as the pipe rotation speed is increased. However, as the cuttings are introduced, due to the reduction in the stationary cuttings bed area, frictional pressure losses may decrease. Additionally, the effect of pipe rotation on hole cleaning as a function of fluid viscosity is also examined. It has been observed that, as the fluid viscosity is increased, contribution of pipe rotation on hole cleaning is increasing when compared with no rotation case.

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Section: Theorymentioning

confidence: 99%

Section: Empirical Correlationsmentioning

confidence: 99%

Effect of Pipe Rotation on Hole Cleaning for Water-Based Drilling Fluids in Horizontal and Deviated Wells

Özbayoğlu

Saasen

Sorgun³

et al. 2008

All Days

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“…Singhal et al (2005) studied the friction pressure losses of Newtonian and non-Newtonian fluids in concentric annuli using FLUENT commercial fluid dynamics software package. Ozbayoglu and Omurlu (2006) studied the flow behavior of three different fluids in annulus of coiled tubing operations by considering 0, 50 and 100% eccentricity. Pereira et al (2007) considered the effect of inner pipe rotation in their CFD analysis in which they used Cross rheological model.…”

Section: Introductionmentioning

confidence: 99%

Computational Modeling of Drilling Fluids Dynamics in Casing Drilling

et al. 2012

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Casing drilling is used as an alternative to conventional drilling with drillpipe in order to reduce non-productive time. The smaller annular space in casing drilling elevates the annular pressure loss considerably at similar flow rates in conventional drilling. Consequently, the Equivalent Circulating Density (ECD) is more affected by annular drilling fluid dynamics in casing drilling than the conventional drilling. The higher ECD experienced in casing drilling brings concerns about exceeding fracture gradient which can lead to induced lost circulation. However, several field observations demonstrate successful application of casing drilling in combating lost circulation and strengthening the wellbore.Smearing effect theory backed by smaller cuttings at the shale shaker, eccentric casing wear, and discrepancy between analytical and field measurements are three main evidences for potential significant eccentricity in casing drilling operations. This paper demonstrates the inherent eccentricity of casing drilling as one of the parameters that controls the annular pressure losses. Eccentricity reduces the velocity in the narrow section of annulus. Similarly, it reduces the annular pressure losses considerably. In addition, controlling the fluid rheological properties as well as the flow rate are recommended to manage the casing drilling hydraulics. This comprehensive study of pressure loss and velocity profile at various annular sizes can help analyzing several field observations and designing the hydraulics of drilling operations.

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“…In the case of 1< ζ <10 the resulting flow called mixed (Escudier et al 2002b). Ozbayoglu and Omurlu (2006) presented a numerical simulation of the flow of non-Newtonian fluid through annulus using commercial CFD software. The geometry consideration in their study corresponds with the common sizes encountered in Coil Tubing application.…”

Section: Figure 1: Casing Drilling and Conventional Drilling Configurmentioning

confidence: 99%

Evaluation of Annular Pressure Losses while Casing Drilling

Dokhani

Shahri

Karimi

et al. 2013

Day 1 Mon, September 30, 2013

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Casing Drilling is an innovative drilling method wherein the well is drilled and cased simultaneously. The small annulus of Casing Drilling can create a controllable dynamic ECD (Equivalent Circulating Density). Casing Drilling technology permits the same desired ECD as conventional drilling to be achieved using a lower, but optimized, flow rate, rheological properties, and mud weight. In this paper, the frictional pressure loss during Casing Drilling operation is evaluated using Computational Fluid Dynamics. Annular pressure losses have received substantial attention in theoretical analyses, laboratory assessment and actual well measurements. Combinations of casing motion, annular eccentricities, wall roughness and fluid temperatures along the length of the annulus affect fluid flow regimes that control annular pressure losses. Current analytical solutions have limited applicability for complex conditions with pipe rotation and eccentricity. In this study, the pressure losses during Casing Drilling operation are investigated using computational fluid dynamics. The results are compared against the available analytical solution and field data. The effect of pipe rotation and eccentricity on the frictional pressure loss is investigated as well. According to the simulation results, the pipe rotation reduces the frictional pressure loss for Yield-Power-law fluid which would be beneficiary during the casing drilling operation. It is found that the pipe eccentricity has a significant effect on the ECD calculation. The industry is moving towards more challenging jobs in narrow pressure window scenarios such as deep-water and HPHT applications. Drilling with casing/liner is among the primary options to complete these sections due to strengthening effects associated with plastering the wellbore wall and also eliminating conventional drill pipe trip. Having accurate models for ECD including the effects of pipe rotation and eccentricity in the narrow annulus is essential to the success of these challenging jobs.

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Analysis of the Effect of Eccentricity on the Flow Characteristics of Annular Flow of Non-Newtonian Fluids Using Finite-Element Method

Cited by 5 publications

References 0 publications

Effect of Pipe Rotation on Hole Cleaning for Water-Based Drilling Fluids in Horizontal and Deviated Wells

Effect of Pipe Rotation on Hole Cleaning for Water-Based Drilling Fluids in Horizontal and Deviated Wells

Computational Modeling of Drilling Fluids Dynamics in Casing Drilling

Evaluation of Annular Pressure Losses while Casing Drilling

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