Experimental Investigation of Drilled Cuttings Transport in Inclined Boreholes

Ford, J.T.; Peden, J.M.; Oyeneyin, Babs; Gao, Erhu; Zarrough, R.

doi:10.2118/20421-ms

Cited by 97 publications

(42 citation statements)

References 15 publications

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“…Gavignet and Sobey 6 also stated in their two-layer model that smaller particles need a higher flow rate to maintain bed motion. Ahmed However, Ford et al 10 observed that as the cuttings size decreases from 2.5-3.7 mm to 1.7-2.0 mm, the Minimum Transport Velocity (MTV) required both for cuttings rolling/sliding and for suspension decreases. It means that smaller cuttings are easier to transport in terms of MTV.…”

Section: Literature Reviewmentioning

confidence: 99%

“…Though different cuttings have been tested by a few investigators, 4,5,7,8,[10][11][12] no study on small cuttings transport in horizontal or high angle annuli involving drill pipe rotation has been conducted. Previous conclusions about the cuttings size effects on cuttings transport are quite diverse, and even contradictory in some cases.…”

Section: Introductionmentioning

confidence: 99%

“…Previous conclusions about the cuttings size effects on cuttings transport are quite diverse, and even contradictory in some cases. [4][5][6][7][10][11][12] Their experiments upon which these conclusions are based were conducted under incomparable conditions. It may not be correct, or at least not safe, to state explicitly that smaller cuttings are harder or easier to transport.…”

Section: Introductionmentioning

confidence: 99%

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Transport of Small Cuttings in Extended Reach Drilling

Duan

Miska

et al. 2006

All Days

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractField experience has shown that inefficient transport of small cuttings is a main factor for excessive drag and torque during extended reach drilling; however, very little is known about the transport behavior of small cuttings. In this study, extensive experiments with three sizes of cuttings (0.45 mm-3.3 mm) were conducted in a field-scale flow loop (8 in.×4.5 in., 100-ft long) to identify the main factors affecting small cuttings transport. The effects of cuttings size, drill pipe rotation, fluid rheology, flow rate and hole inclination were investigated.The results show significant differences in cuttings transport based on cuttings size. Smaller cuttings result in a higher cuttings concentration than larger cuttings in a horizontal annulus when tested with water. However, a lower concentration was achieved for smaller cuttings when 0.25 ppb Polyanionic Cellulose (PAC) solutions were used. Unlike the transport of large cuttings, which is mainly dominated by fluid flow rate, the key factors controlling small cuttings transport were found to be pipe rotation and fluid rheology. Improvement by pipe rotation in the transport efficiency of small cuttings is up to twice as large as the improvement in large cuttings transport. Compared with water, PAC solutions significantly improve smaller cuttings transport, while the transport of larger cuttings is only slightly enhanced.Mathematical modeling was performed to develop correlations for cuttings concentration and bed height in an annulus for field applications. Predictions from a three-layer model previously developed for larger cuttings were also compared with experimental results. Differences (up to 80%) indicate the need for improving the frequently used three-layer model by including correlations specifically developed for small cuttings to get a better design of extended reach drilling. This study is also useful for horizontal or high-angle well drilling and completion through sand reservoirs.

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Section: Literature Reviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Transport of Small Cuttings in Extended Reach Drilling

Duan

Miska

et al. 2006

All Days

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“…A number of experimental and modeling studies (Sifferman & Becker 1992;Brown 1986;Clark and Bickham 1994;Ford et al 1990) have been carried out to determine the effect of the angle of inclination. The studies indicate that the effect of inclination on cuttings transport is substantial.…”

Section: Literature Reviewmentioning

confidence: 99%

Experimental Studies on the Effect of Mechanical Cleaning Devices on Annular Cuttings Concentration and Applications for Optimizing ERD Systems

et al. 2010

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In horizontal and highly deviated portions of an Extended Reach Drilling (ERD) well, cuttings beds form on the low-side of the annulus. The bed partially blocks the annulus resulting in excessive pressure loss and a higher equivalent circulating density (ECD) that is exacerbated by the increase in length of the annulus. This condition limits hole-cleaning capabilities. As a result, selecting favorable drilling parameters is not always sufficient to overcome the hole cleaning problem. Recently, the use of downhole Mechanical Cleaning Devices (MCDs) has been introduced to the industry to mitigate the problem without inducing excessive ECD. Although the use of these tools is increasing, very limited studies have been conducted to optimize their performance.This paper presents results of an experimental study that was carried out to evaluate cuttings removal efficiency of MCDs and applications of MCDs for optimizing ERD systems. Experiments were carried out in a large-scale flow loop that has an 8-inch transparent test section. Three different drillpipe sizes were considered in the investigation. The Taguchi approach was implemented to reduce the number of experiments while covering the most relevant parameters such as flow rate, ROP, diameter ratio, tool design and drillpipe rotation speed. For each test, the amount of cuttings accumulated in the test section was determined from weight measurements. Results indicate that the tools significantly reduce the amount of cuttings in the annulus, especially around the MCDs, compared to locations where there is no tool.Experimental results were evaluated to obtain the overall effect of operating parameters on annular cuttings concentration and develop correlations. The results show that the flow rate and inclination angle have the most significant impact. The correlations are useful to develop an analytical model for designing and optimizing drilling systems with MCDs, either in terms of operating parameters or drillstring design.

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“…Experimental studies have shown that hole cleaning is affected by many parameters, such as well geometry (diameter, inclination, eccentricity), cuttings characteristics (size, porosity of bed), drilling fluid properties (rheology, density, drag coefficient) and drilling operational parameters (drilling rate, drilling fluid circulation rate) (3)(4)(5)(6)(7) .…”

Section: Introductionmentioning

confidence: 99%

Numerical Modelling of Cuttings Transport in Horizontal Wells Using Conventional Drilling Fluids

Bjorndalen

Kuru

2007

Journal of Canadian Petroleum Technology

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A one-dimensional transient mechanistic model of cuttings transport with conventional (incompressible) drilling fluids in horizontal wells has been developed. The model is solved numerically to predict cuttings bed height as a function of drilling fluid flow rate and rheological characteristics (n, K), drilling rates, wellbore geometry and drill pipe eccentricity. The results of the sensitivity analysis showing the effects of various drilling operational parameters on the efficiency of solids transport are presented. The model developed in this study can be used to develop computer programs for practical design purposes to determine optimum drilling fluid rheology (n, K) and flow rates required for drilling horizontal wells. Introduction Poor hole cleaning can lead to pipe sticking, higher drag and torque, slower rate of penetration, formation fractures and wellbore steering problems(1). It has been estimated that one third of stuck pipe problems are due to inadequate hole cleaning(2). Optimization of drilling hydraulics design for trouble free drilling, therefore, requires a good understanding of the mechanics of cuttings transport. Experimental studies have shown that hole cleaning is affected by many parameters, such as well geometry (diameter, inclination, eccentricity), cuttings characteristics (size, porosity of bed), drilling fluid properties (rheology, density, drag coefficient) and drilling operational parameters (drilling rate, drilling fluid circulation rate)(3–7). Based on the results from experimental studies, empirical models were developed(8–13) and rules of thumb for field practices were also suggested(14–16). Cuttings transport has also been investigated extensively by using analytical models. Two-layer(1,17–22) and three-layer(23,24) mechanistic models of cuttings transport were developed. Most of the existing models do not consider the slip velocity between solids and drilling fluids. In some cases, the authors simply neglected the slip velocity and treated the flow of the liquid-solids mixture as homogeneous flow(20,21,23,24), while others simply assumed the slip velocity is equal to the solids terminal settling velocity(19). Steady-state transport of cuttings is the major assumption inherent in all of the previous cuttings transport models. Therefore, the transient nature of the cuttings transport cannot be studied adequately by using these models. As the drilling goes on, cuttings are continuously deposited along the horizontal wellbore. There is a critical limit for cuttings bed height above which drilling operation exhibits a high risk of operational integrity, such as risk of lost circulation due to high ECD, increased probability of pipe sticking, high drag and torque. The common practice is to stop drilling occasionally and clean the borehole by using viscous pills, pipe rotation and reciprocation, and drilling fluid circulation. It is very critical to be able to predict after how many hours of operation drilling should be stopped and remedial wellbore cleaning actions be resumed. A transient cuttings transport model is, therefore, needed for better design of drilling hydraulics; in particular for drilling long horizontal sections of the wellbore and extended reach (ERD) wells. In this study, a 1D transient, mechanistic model of cuttings transport with conventional (incompressible) drilling fluids in horizontal wells has been developed. The prediction of cuttings bed as a function of various drilling operational parameters is presented. A detailed description of t

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Experimental Investigation of Drilled Cuttings Transport in Inclined Boreholes

Abstract: This paper describes an experimental investigation into drilled cuttings transport in inclined boreholes carried out in the Department of Petroleum Engineering at Heriot-Watt University.

Cited by 97 publications

References 15 publications

Transport of Small Cuttings in Extended Reach Drilling

Transport of Small Cuttings in Extended Reach Drilling

Experimental Studies on the Effect of Mechanical Cleaning Devices on Annular Cuttings Concentration and Applications for Optimizing ERD Systems

Numerical Modelling of Cuttings Transport in Horizontal Wells Using Conventional Drilling Fluids

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