Accurate determination of hydraulic parameters such as pressure losses, equivalent circulation density (ECD), etc. plays profound roles in drilling, cementing and other well operations. Hydraulics characterization requires that all factors are considered as the neglect of any could become potential sources of errors that would be detrimental to the overall well operation. Drilling Hydraulics has been extensively treated in the literature. However, these works almost entirely rely on the assumption that the drill string lies perfectly at the center of the annulus—the so-called “concentric annulus”. In reality, concentricity is almost never achieved even when centralizers are used. This is because of high well inclination angles and different string geometries. Thus, eccentricity exists in practical oil and gas wells especially horizontal and extended reach wells (ERWs) and must be accounted for. The prevalence of drillstring (DS) eccentricity in the annulus calls for a re-evaluation of existing hydraulic models. This study evaluates the effect of drilling fluid rheology types and DS eccentricity on the entire drilling hydraulics. Three non-Newtonian fluid models were analyzed, viz: Herschel Bulkley, power law and Bingham plastic models. From the results, it was observed that while power law and Bingham plastic models gave the upper and lower hydraulic values, Herschel Bulkley fluid model gave annular pressure loss (APL) and ECD values that fall between the upper and lower values and provide a better fit to the hydraulic data than power law and Bingham plastic fluids. Furthermore, analysis of annular eccentricity reveals that APLs and ECD decrease with an increase in DS eccentricity. Pressure loss reduction of more than 50% was predicted for the fully eccentric case for Herschel Bulkley fluids. Thus, DS eccentricity must be fully considered during well planning and hydraulics designs.
References
[1]
Ochoa, M.A. (2006) Analysis of Drilling Fluid Rheology and Tool Joint Effect to Reduce Errors in Hydraulics Calculations. PhD Thesis, Texas A&M University, Texas.
[2]
Ahmed, R. and Miska, S. (2008) Study and Modeling of Yield Power-Law Fluid Flow in Annuli with Drillpipe Rotation. Paper Presented at the IADC/SPE Drilling Conference, Orlando, March 2008, Paper No. SPE 112604. https://doi.org/10.2118/112604-MS
[3]
Ahmed, R., Miska, S.Z. (2009) Chapter 4.1. Advanced Wellbore Hydraulics. In: Aadnoy, B., Cooper, I., Miska, S., Mitchell, R.F. and Payne, M.L., Eds., Advanced Drilling and Well Technology, Society of Petroleum Engineers, Richardson, TX, 191-219.
[4]
Hemphill, T., Campos W. and Pilehvari A. (1993) Yield-Power Law Model More Accurately Predicts Mud Rheology. Oil & Gas Journal, 91, 45-50.
[5]
Erge, O., Karimi V.A, Ozbayoglu, E.M. and Oort, E. (2016) Improved ECD Prediction and Management in Horizontal and Extended Reach Wells with Eccentric Drillstrings. Paper Presented at the IADC/SPE Drilling Conference and Exhibition, Fort Worth, March 2016, Paper No. SPE-178785-MS. https://doi.org/10.2118/178785-MS
[6]
Erge, O., Ozbayoglu, E.M., Miska, S.Z., Yu, M., Takach, N., Saasen, A. and May, R. (2016) Equivalent Circulating Density Modeling of Yield Power Law Fluids Validated with CFD Approach. Journal of Petroleum Science and Engineering, 140, 16-27. https://doi.org/10.1016/j.petrol.2015.12.027
[7]
Erge, O., Ozbayoglu, E. M., Miska, S. Z., Yu, M., Takach, N., Saasen, A., May, R. (2014) Effects of Drillstring Eccentricity, Rotation and Buckling Configurations on Annular Frictional Pressure Losses While Circulating Yield Power Law Fluids. SPE Drilling & Completion, 30, 257-271. https://doi.org/10.2118/167950-PA
[8]
Kerunwa, A. (2020) Contributory Influence of Drill Cuttings on Equivalent Circulation Density Model in Deviated Wellbores. International Journal of Oil, Gas and Coal Engineering, 8, 82-90. https://doi.org/10.11648/j.ogce.20200804.12
[9]
Erge, O., Ozbayoglu, E. M., Miska, S. Z., Yu, M., Takach, N., Saasen, A. and May, R. (2015) Analysis and Model Comparison of Annular Frictional Pressure Losses While Circulating Yield Power Law Fluids. Paper Presented at the SPE Bergen One Day Seminar, Bergen, April 2015, Paper No. SPE 173840. https://doi.org/10.2118/173840-MS
[10]
Hansen, S.A. and Sterri, N. (1995) Drill Pipe Rotation Effects on Frictional Pressure Losses in Slim Annuli. Paper Presented at the SPE Annual Technical Conference and Exhibition, Dallas, October 1995, Paper No. SPE 30488. https://doi.org/10.2118/30488-MS
[11]
Piercy, N.A.V., Hooper, M.S. and Winny, H.F. (1933) Viscous Flow through Pipes with Core. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 15, 647-676. https://doi.org/10.1080/14786443309462212
[12]
Kozicki, W., Chou, C.H. and Tiu, C. (1966) Newtonian Flow in Ducts of Arbitrary Cross-Sectional Shape. Chemical Engineering Science, 21, 665-679. https://doi.org/10.1016/0009-2509(66)80016-7
[13]
Haciislamoglu, M. (1989) Non-Newtonian Fluid Flow in Eccentric Annuli and Its Application to Petroleum Engineering Problems. Ph.D Dissertation, Louisiana State University, Baton Rouge, LA.
[14]
Haciislamoglu, M. and Langlinais, J. (1990) Non-Newtonian Flow in Eccentric Annuli. Journal of Energy Resources Technology, 112, 163-169. https://doi.org/10.1115/1.2905753
[15]
Luo, Y. and Peden, J.M. (1990) Flow of Non-Newtonian Fluids through Eccentric Annuli. SPE Production Engineering, 5, 91-96. https://doi.org/10.2118/16692-PA
[16]
Subramanian, R. and Azar, J.J. (2000) Experimental Study on Friction Pressure Drop for NonNewtonian Drilling Fluids in Pipe and Annular Flow. Paper Presented at the International Oil and Gas Conference and Exhibition in China, Beijing, November 2000, Paper No. SPE-64647-MS. https://doi.org/10.2118/64647-MS
[17]
Adariani, H.Y. (2005) Simulation of Laminar Flow of Non-Newtonian Fluids in Eccentric Annuli. M.Sc. Thesis, University of Tulsa, Tulsa.
[18]
Sestak, J., Zitny, R., Ondrusova J. and Filip, V. (2001) Axial Flow of Purely Viscous Fluids in Eccentric Annuli: Geometric Parameters for Most Frequently Used Approximate Procedures. 3rd Pacific Rim Conference on Rheology, Vancouver, 8-13 July, 1-3.
[19]
Ahmed, R., Miska, S.Z. and Miska, W.Z. (2006) Friction Pressure Loss Determination of Yield Power Law Fluid in Eccentric Annular Laminar Flow. Wiertnictwo Nafta Gaz, 23, 47-53.
[20]
Pilehvari, A. and Serth, R. (2009) Generalized Hydraulic Calculation Method for Axial Flow of NonNewtonian Fluids in Eccentric Annuli. SPE Drilling & Completion, No. 24, 553-563. https://doi.org/10.2118/111514-PA
[21]
Ahmed, R.M., Enfis, M.S., El Kheir, H.M., Laget, M. and Saasen, A. (2010) The Effect of Drillstring Rotation on Equivalent Circulation Density: Modeling and Analysis of Field Measurements. Paper Presented at the SPE Annual Technical Conference and Exhibition, Florence, September 2010, Paper SPE 135587. https://doi.org/10.2118/135587-MS
[22]
Sorgun, M. and Ozbayoglu, M. E. (2011) Predicting Frictional Pressure Loss during Horizontal Drilling for Non-Newtonian Fluids. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 33, 631-640. https://doi.org/10.1080/15567030903226264
[23]
Sorgun, M. (2011) Computational Fluid Dynamics Modeling of Pipe Eccentricity Effect on Flow Characteristics of Newtonian and Non-Newtonian Fluids. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 33, 1196-1208. https://doi.org/10.1080/15567036.2010.492381
[24]
Anifowoshe, O.L. and Osisanya, S.O. (2012) The Effect of Equivalent Diameter De finitions on Frictional Pressure Loss Estimation in an Annulus with Pipe Rotation. Paper Presented at the SPE Deepwater Drilling and Completions Conference, Galveston, June 2012, Paper No. SPE 151176. https://doi.org/10.2118/151176-MS
[25]
Vajargah, A.K. and Oort, E.V. (2015) Automated Drilling Fluid Rheology Characterization with Downhole Pressure Sensor Data. Paper Presented at the SPE/IADC Drilling Conference and Exhibition, London, Paper No. SPE 173085. https://doi.org/10.2118/173085-MS
[26]
Mokhtari, M., Ermila, M. and Tutuncu, A.N. (2012) Accurate Bottomhole Pressure for Fracture Gradient Prediction and Drilling Fluid Pressure Program—Part I. 46th U.S. Rock Mechanics/Geomechanics Symposium, Vol. ARMA-2012-235, Chicago, 24-27 June 2012, 1-14.
[27]
Vajargah, A.K. and Oort, E.V. (2015) Determination of Drilling Fluid Rheology under Downhole Conditions by Using Real-Time Distributed Pressure Data. Journal of Natural Gas Science and Engineering, 24, 400-411. https://doi.org/10.1016/j.jngse.2015.04.004
[28]
Kristensen, A. (2013) Flow Properties of Water-Based Drilling Fluids. Master’s Thesis, Norwegian University of Science and Technology, Trondheim.
[29]
Akrong, J.A. (2010) Effect of Pipe Eccentricity on Hole Cleaning and Wellbore Hy draulics. Master’s Thesis, African University of Science and Technology, Abuja.
[30]
Kerunwa, A. (2020) Drillstring Buckling Prediction and its Impact on Tool-Joint Effects in Extended Reach Wells. International Journal of Oil, Gas and Coal Engineering, 8, 157-166. https://doi.org/10.11648/j.ogce.20200806.16
[31]
Hemphill, T. and Ravi K. (2006) Pipe Rotation and Hole Cleaning in an Eccentric Annulus. Paper Presented at 2006 IADC/SPE, Miami, Florida, 21-23 February, Paper No. SPE 99150.
[32]
Pereira, F.A.R., Ataíde, C.H. and Barrozo, M.A.S. (2010) CFD Approach Using a Discrete Phase Model for Annular Flow Analysis. Latin American Applied Research, 40, 53-60.
