Abstract
Extensive studies on cuttings transport have been conducted by many researchers over the years. In an attempt to better understand the factors influencing cuttings removal in the wellbore, the behaviour of drill-cuttings in the annulus has been simulated and measured under various conditions in the laboratory using mainly water-based and oil-based muds. Furthermore, empirical and semi-empirical correlations as wells as mathematical models have also been developed under specific conditions by other investigators to ease the difficulties and complexities encountered by field engineers during drilling operations. In addition, qualitative hydraulic programmes have also been outlined to provide field guidelines for improved hole cleaning. In recent times, the use of computational fluid dynamics (CFD) in parametric study of cuttings transport has gained popularity due to its ability to handle unlimited number of physical and operational conditions as well as eliminating the need for expensive experimental set-ups. This paper seeks to review the factors or combination of factors affecting cuttings transport as well as the various hydraulic programmes applicable to solving the prevailing field drilling problems in horizontal wellbores.
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1 Introduction
There are huge amount of literature available on the study of cuttings transport due to its interest and complexity in understanding the transport behaviour. Till date, more research are being conducted as the well-known conventional rotary drilling method used in drilling onshore reservoirs are now replaced by coiled tubing drilling, casing drilling, etc., due to the challenging frontiers encountered in recent deep and ultra-deep offshore reservoirs. To better understand the various mechanisms affecting cuttings transport in horizontal wellbores, many investigators have conducted various studies under varying conditions by employing different approaches as follows: experimental, numerical simulation, mathematical modelling and field case study. The factors affecting cuttings transport in horizontal wellbores have been critically reviewed and addressed. It is believed that cuttings transported in the annulus are not always affected by a single parameter but a combination of parameters to ensure efficient hole cleaning. This study is aimed at reviewing all available literature on two-phase cuttings-liquid transport in horizontal annular wellbores where conventional drilling fluids such as pure water, water-based muds and oil-based muds are used in the drilling process.
2 Factors Affecting Cuttings Transport
Cuttings transported through the annulus (hole–pipe geometry) are affected by series of drilling parameters. The study of the effects of these parameters has been a subject of research by several investigators over the decades. According to these investigators, the factors affecting cuttings transport in the wellbore can be summarised as but not limited to: annular fluid velocity (flow rate), drill pipe eccentricity, wellbore size (annular size), drilling fluid rheology (density, viscosity, yield point, gel strength), cuttings size, drill pipe rotation, drilling rate (rate of penetration), hole inclination, mud type, temperature and drilling fluid density. Overestimation or underestimation of these parameters may result in hole problems such as cavings, enlargements, closures, mud cake formation and excessive cuttings bed as depicted in Fig. 1. Therefore, there is the need to optimise these parameters for effective hole cleaning.
Reference [1] has illustrated in Fig. 2 that the practical use of these factors in controlling cuttings transport is much dependent on their controllability in the field.
2.1 Effect of Annular Velocity (Flow Rate)
Figure 2 indicates that flow rate has the most significant influence on cuttings transport and hence could be easily controlled. Both experimental studies and numerical simulations of cuttings transport have shown that higher flow rates result in drastic cuttings bed erosion [1–11]. Reference [12] observed that increasing flow rate of high-viscosity high-density sweep or high-viscosity sweep has no significant improvement on cuttings bed erosion. In addition, [13] observed a decrease in the critical flow rate required to reduce cuttings bed height as the open flow area decreases.
2.2 Effect of Drilling Fluid Density
Drilling fluid density or mud weight determines the cuttings carrying capacity. Mud weight is illustrated in Fig. 2 as one of the influential parameters on hole cleaning which could be moderately controlled on the field. Studies [5, 6, 14, 15] have shown that increase in fluid density enhances cuttings bed erosion and also prevents borehole collapse [16]. At high mud weight, the frictional effect of cuttings on rotating drill pipe also reduces [17]. Reference [18] indicated that fluid density is only a secondary factor in cuttings transport at constant critical flow rate.
2.3 Effect of Drilling Fluid Rheology
Fluid rheology also plays great role on hole cleaning as observed from Fig. 2. Experimental studies [19, 20] have shown that cuttings bed formation in high-viscosity fluids in laminar flow is slow compared low-viscosity fluids in laminar flow. On the contrary, other investigators [21, 22] have also observed that low-viscosity muds perform better than high-viscosity muds, whereas low-viscosity muds which are pumped in turbulent flow are more effective in hole cleaning than high-viscosity muds in laminar flow [23]. Furthermore, low-viscosity muds transport more large-sized cuttings than small-sized cuttings [24]. In addition, [12] noted that high-viscosity sweeps in the absence of drill pipe rotation is ineffective in cuttings bed erosion and cuttings removal, whereas low-viscosity sweeps with drill pipe rotation and improves ‘sweep’ efficiency at high flow rates. The effect of mud viscosity on cuttings transport however diminishes as drill pipe rotation speed increases [10].
On the other hand, a decrease in flow behaviour index, n, results in a decrease of stationary bed, whereas moving bed layer increases [25]. Reference [1] also observed that the increase in the ratio of flow behaviour index to consistency index (n/K) reduces cuttings bed height. Less gel strength formation in muds also helps minimise cuttings bed consolidation [16]. The mud yield point (YP) and plastic viscosity (PV) also influence cuttings removal. Further study [12] has shown that increase in YP at constant flow rate without drill pipe rotation results in negligible cuttings bed erosion, while a reduction in PV and YP results in a better hole cleaning at reduced flow rates [22].
2.4 Effect of Cuttings Size
The size of cuttings is mostly dependent on the type of formation being drilled as well as the type of drill bits. This parameter, as shown in Fig. 2, is very difficult to control. A general observation made by previous studies [3, 6, 23] shows that large-sized cuttings result in an increase in cuttings bed height. However, smaller-sized cuttings are observed to be more difficult to clean when using water as drilling fluid [8, 23] and, thus, require a higher flow rate to reach the critical transport fluid velocity (CTFV) due to their high interface interaction coefficient when using non-Newtonian fluids [21, 26, 27].
2.5 Effect of Drill Pipe Rotation
The rotation of drill pipe during drilling operations is shown to moderately influence hole cleaning and can be controlled as well (see Fig. 2). According to [19], drill pipe rotation has minor influence on cuttings transport when flow is turbulent. Higher drill pipe rotation speed is also observed effective in decreasing annular cuttings concentration at low flow rates and diminishes at high flow rates [9, 24, 28]. Cuttings bed erosion is greatly improved by drill pipe rotation once drilling operation is stopped [24]. Reference [29] observed that drill pipe rotation enhances better hole cleaning when high-density sweep is used, whereas at low-viscosity sweep, a considerable decrease in cuttings bed erosion is noted as drill pipe rotation increases [12]. Another investigator [30] also noticed greater impact of drill pipe rotation in transporting smaller cuttings sizes. However, other studies [9, 28] observed a slight decrease in cuttings moving velocity; hence, a negligible change in cuttings bed height as drill pipe rotation increases.
2.6 Effect of Drill Pipe Eccentricity
Eccentricity shows how drill pipe is displaced either towards the upper or lower part in horizontal wellbores. The influence on cuttings transport is extremely high, but it is also very difficult to control as depicted in Fig. 2. Studies [14] have shown that concentric annuli promote more cuttings bed erosion than eccentric annuli. In addition, others [3, 5, 15] also confirmed that an increase in eccentricity increases cuttings bed.
2.7 Effect of Annular Size
Annular size shows huge influence on cuttings transport as illustrated in Fig. 2. Experimental studies [31] have shown that increase in diameter ratio (a ratio of drill pipe diameter to hole diameter) improves hole cleaning due to the increase in annular velocity and wall shear stress.
2.8 Effect of Fluid Type
Reference [13] noticed that water, as a drilling fluid, is more effective for cuttings bed erosion, while PAC fluid is more effective in preventing cuttings bed formation. Meanwhile, PAC solution is also seen to improve the transport of small-sized cuttings than large-sized cuttings [8].
2.9 Effect of Drilling Rate (Rate of Penetration, ROP)
Several investigators [6, 9, 30] and [32] have illustrated that higher drilling rates generate more cuttings in the wellbore and hence results in higher cuttings bed height. This effect further increases the hydraulic requirement for effective hole cleaning [19, 24].
2.10 Effect of Temperature
Very few experimental studies [12, 33] have been conducted in recent times under elevated temperature to analyse its effect on cuttings transport. It can be ascertained from these studies that an increase in temperature results in a decrease in cuttings bed height with time when using both water and non-Newtonian fluids. Other observation is that the rheology of drilling fluids changes significantly with temperature, which affects the viscous drag forces applied on drilled cuttings [33].
3 Drilling Hydraulic Programmes
The complexity of cuttings transport, which involves the combination of interacting variables, would not make it prudent to solely rely on predictive models with limited boundary conditions. In this regard, many investigators have recommended some general operational guidelines based on the results from laboratory study as well as field experience and observations. Appendix A summarises these operational guidelines in Tables 1 and 2.
4 Conclusion
A comprehensive study on the factors affecting cuttings transport in horizontal wellbores has been presented. The most important factor controlling cuttings transport or hole cleaning is annular velocity as illustrated in Fig. 2. Fluid rheological properties and density have moderate influence, whiles cuttings size, annular gap, drilling rate, drill pipe eccentricity and rotation have slight effect on cuttings transport. It is evident that different authors had different opinions on specific drilling parameter effects. This could be attributed to the range of composition of parameters as well as experimental and numerical set-up range used in their respective studies. This review clearly shows that effective hole cleaning is not dependent only on a single drilling parameter but also on a combination of parameters. Qualitative hydraulic programmes for ensuring efficient hole cleaning and wellbore stability as proposed by other investigators are also presented.
References
R.B. Adari, S. Miska, E. Kuru, P. Bern, and A. Saasen, “Selecting Drilling Fluid Properties and Flow Rates for Effective Hole Cleaning in High-Angle and Horizontal Wells” SPE 63050, presented at SPE Annual Technical Conference and Exhibition, Dallas, Texas, (2000).
A.L. Martins, M. Santana, E. Gaspari, and W. Campos, “Evaluating the Transport of Solids Generated by Shale Instabilities in ERW Drilling” SPE 50380, presented at the SPE International Conference on Horizontal Well Technology held in Calgary, Alberta, Canada, (1998).
A.M. Kamp, and M. Rivero, “Layer Modeling for Cuttings Transport in Highly Inclined Wellbores” SPE 53942, presented at the SPE Latin American and Caribbean Petroleum Engineering Conference held in Caracas, Venezuela, (1999).
L. Zou, M.H. Patel, and G. Han, “A New Computer Package for Simulating Cuttings Transport and Predicting Hole Cleaning in Deviated and Horizontal Wells” SPE 64646, presented at the International Oil and Gas Conference and Exhibition held in Beijing, China, (2000).
M.E. Ozbayoglu, S.Z. Miska, T. Reed, and N. Takach, “Analysis of the Effects of Major Drilling Parameters on Cuttings Transport Efficiency for High-Angle Wells in Coiled Tubing Drilling Operations” SPE 89334, presented at the SPE/ICoTA Coiled Tubing Conference and Exhibition held in Houston, Texas, USA, (2004).
Y. Li, N. Bjorndalen, and E. Kuru, “Numerical Modeling of Cuttings Transport on Horizontal Wells Using Conventional Drilling Fluids” Paper 2004-227, presented at the Petroleum Society’s 5th Canadian International Petroleum Conference (55th Annual Technical Meeting), Calgary, Alberta, Canada, (2004).
M.E. Ozbayoglu, A. Saasen, M. Sorgun, and K. Svanes, “Estimating Critical Velocity to Prevent Bed Development for Horizontal-Inclined Wellbores” SPE/IADC 108005, presented at the SPE/IADC Middle East Drilling Technology Conference and Exhibition held in Cairo, Egypt, (2007).
M. Duan, S. Miska, M. Yu, N. Takach, R. Ahmed, and C. Zettner, “Transport of Small Cuttings in Extended-Reach Drilling” SPEJ 104192, (2008), pp. 258-265.
M.E. Ozbayoglu, R.O. Ettehadi, A.M. Ozbayoglu, and E. Yuksel, “Estimation of “Very-Difficult-to-Identify” Data for Hole Cleaning, Cuttings Transport and Pressure Drop Estimation in Directional and Horizontal Drilling” SPE/IADC 136304, (2010)
M. Sorgun, I. Aydin, and M.E. Ozbayoglu, “Friction Factor for Hydraulic Calculations Considering Presence of Cuttings and Pipe Rotation in Horizontal / Highly-Inclined Wellbores” Journal of Petroleum Science and Engineering 78 (2011) pp. 407-414.
J.O. Ogunrinde, and A. Dosunmu, “Hydraulic Optimization for Efficient Hole Cleaning in Deviated and Horizontal Wells” SPE 162970, (2012).
S.G. Valluri, S.Z. Miska, R. Ahmed, M. Yu, and N. Takach, “Experimental Study of Effective Hole Cleaning Using “Sweep” in Horizontal Wellbores” SPE 101220, presented at the SPE Annual Technical Conference and Exhibition held in San Antonio, Texas, USA, (2006).
M. Duan, S. Miska, M. Yu, N. Takach, R. Ahmed, and C. Zettner, “Critical Conditions for Effective Sand-Sized-Solids Transport in Horizontal and High-Angle Wells” SPEJ 106707, (2009), pp. 229-239.
A.L. Martins, C.H.M. Sa, A.M.F. Lourenco, and W. Campos, “Optimizing Cuttings Circulation in Horizontal Well Drilling” SPE 35341, presented at the International Petroleum conference and Exhibition of Mexico held in Villahermosa, Mexico, (1996).
D. Nguyen, and S.S. Rahman, “A Three -Layer Hydraulic Program for Effective Cuttings Transport and Hole Cleaning in Highly Deviated and Horizontal Wells” SPEJ 51186, (1998).
I. Kjosnes, G. Loklingholm, A. Saasen, S.O. Syrstad, A. Agle, and K.A. Solvang, “Successful Water Based Drilling Fluid Design for Optimizing Hole Cleaning and Hole Stability” SPE/IADC 85330, presented at the SPE/IADC Middle East Drilling Technology Conference and Exhibition held in Dhubai, UAE, (2003).
T.E. Becker, and J.J. Azar, “Mud-Weight and Hole-Geometry Effects on Cuttings Transport While Drilling Directionally” SPE 14711, SPE Manuscript, (1985).
T. Hemphill, and T.I. Larsen, “Hole-Cleaning Capabilities of Water-and-Oil-Based Drilling Fluids: A Comprehensive Experimental Study” SPEJ 26328, (1996) pp. 201-207.
P.H. Tomren, A.W. Iyoho, and J.J. Azar, “Experimental Study of Drilled Cuttings Transport in Directional Wells” SPEJ 12123, (1986), pp. 43-56.
T.E. Becker, J.J. Azar, and S.S. Okrajni, “Correlations of Mud Rheological Properties with Cuttings-Transport Performance in Directional Drilling” SPEJ 19535, (1991), pp. 16-24.
T.I. Larsen, A.A. Pilehvari, and J.J. Azar, “Development of a New Cuttings-Transport Model for High-Angle Wellbores Including Horizontal Wells” SPEJ 25872, (1997), PP. 129-135.
M. Mohammadsalehi, and N. Malekzadeh, “Optimization of hole Cleaning and cuttings Removal in Vertical, Deviated and Horizontal Wells” SPE 143675, presented at the Asia Pacific Oil and Gas Conference and Exhibition held in Jakarta, Indonesia, (2011).
S. Walker, and J. Li, “The Effects of Particle Size, Fluid Rheology, and Pipe Eccentricity on Cuttings Transport” SPE 60755, presented at the SPE/ICoTA Coiled Tubing Roundtable held in Houston, TX, (2000).
R.A. Sanchez, J.J. Azar, A.A. Bassal, and A.L. Martin, “Effect of Drillpipe Rotation on Hole Cleaning During Directional-Well Drilling” SPEJ 56406, (1999) PP. 101-108.
H. Cho, S.N. Shah, and S.O. Osisanya, “A Three-Segment Hydraulic Model for Cuttings Transport in Horizontal and Deviated Wells” SPE/PSCIM 65488, presented at the SPE/Petroleum Society of CIM International Conference on Horizontal Well Technology held in Calgary, Alberta, Canada, (2000).
Y. Masuda, Q. Doan, M. Oguztoreli, S. Naganawa, T. Yonezawa, A. Kobayashi, and A. Kamp, “Critical Cuttings Transport Velocity in Inclined Annulus: Experimental Studies and Numerical Simulation” SPE 65502, presented at the SPE/Petroleum Society of CIM International Conference on Horizontal Well Technology held in Calgary, Alberta, Canada, (2000).
S.A. Mirhaj, S.R. Shadizadeh, and M. Fazaelizadeh, “Cuttings Removal Simulation for Deviated and Horizontal Wellbores” SPE 105442, (2007).
M.E. Ozbayoglu, A. Saasen, M. Sorgun, and K. Svanes, “Effects of Pipe Rotation on Hole Cleaning for Water-Based Drilling Fluids in Horizontal and Deviated Wells” IADC/SPE 114965, presented at the SPE/IADC Asia Pacific Drilling Technology Conference and Exhibition held in Jakarta, Indonesia, (2008).
T. Hemphill, and K. Ravi, “Pipe Rotation and Hole Cleaning in an Eccentric Annulus” IADC/SPE 99150, presented at the IADC/SPE Drilling Conference held in Miami, Florida, USA, (2006).
H.I. Bilgesu, N. Mishra, and S. Ameri, “Understanding the Effects of Drilling Parameters on Hole Cleaning in Horizontal and Deviated Wellbores using Computational Fluid Dynamics” SPE 111208, presented at the SPE Eastern Regional Meeting held in Lexington, Kentucky, USA, (2007).
R. Ahmed, M. Sagheer, N. Takach, R. Majidi, M. Yu, S. Miska, C. Rohart, and J. Boulet, “Experimental Studies on the Effect of Mechanical Cleaning Devices on Annular Cuttings Concentration and Applications for Optimizing ERD Systems” SPE 134269, presented at SPE Annual Technical Conference and Exhibition held in Florence, Italy (2010).
S.S. Costa, S. Stuckenbruck, S.A.B. da Fontoura, and A.L. Martins, “Simulation of Transient Cuttings Transportation and ECD in Wellbore Drilling” SPE 113893, presented at the SPE Europec/EAGE Annual Conference and Exhibition held in Rome, Italy, (2008).
M. Yu, and N.E. Takach, “An Experimental Study of Hole Cleaning under Simulated Downhole Conditions” Paper SPE 109840, presented at the SPE Annual Technical Conference and Exhibition, Anaheim, California, 11-14 November, 2007.
G.J. Guild, I.M. Wallace, and M.J. Wassenborg, “Hole Cleaning Program for Extended Reach Wells” SPE/IADC 29381, presented at the SPE/IADC Drilling Conference held in Amsterdam, (1995).
A.A. Pilehvari, J.J. Azar, and S.A. Shirazi, “State-of-the-Art Cuttings Transport in Horizontal Wellbores” SPEJ 57716, (1999), pp. 196-200
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Ofei, T.N., Irawan, S., Pao, W. (2015). Drilling Parameter Effects on Cuttings Transport in Horizontal Wellbores: A Review. In: Awang, M., Negash, B., Md Akhir, N., Lubis, L. (eds) ICIPEG 2014. Springer, Singapore. https://doi.org/10.1007/978-981-287-368-2_18
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