Improved Rheological Model of Oil-Based Drilling Fluid for South-western Iranian Oilfields

Document Type: Research Paper


Department of Mechanical Engineering, Shahid Chamran University of Ahwaz, Ahwaz, Iran


In this study, predictive capabilities of apparent viscosity of oil-based drilling fluids which is used in National Iranian South Oilfields Company (NISOC) were evaluated using Newtonian and non-Newtonian models to drive a new suitable equation. The non-Newtonian models include Bingham plastic, Power law, Herschel-Bulkley, Casson, and Robertson-Stiff. To validate the results, the calculated viscosity from rheology models was compared to the fann 35 data of viscometer. The results showed that Robertson-Stiff model has the best prediction of shear stress and viscosity with an absolute average percent error of 3.58. This was followed by Herschel-Bulkley, Casson, Power law, Bingham plastic, and Newtonian with the absolute average percent error of 3.68, 3.77, 9.04, 20.09, and 44.02 respectively. Therefore, the new equation was proposed to predict the shear stress for oil-based drilling fluids which is used in Southwestern Iranian Oilfields. In comparison to the results of the experimental data of this study, it was revealed that the proposed equation has a good agreement with the real shear stress and apparent viscosities.


Bourgoyne A. T., Chenevert M. E., Millheim K. K., and Young F. S., “Applied Drilling Engineering,” SPE Textbook Series, Richardson, TX, 1991.

Coussot P., Bertrand F., and Herzhaft B., “Rheological Behavior of Drilling Muds, Characterization Using MRI Visualization,” Oil & Gas Science and Technology–Rev. IFP, 2004, 59(1), 23-29.

Rooki R., Doulati Ardejani F., Moradzadeh A., Mirzaei H., and et al., “Optimal Determination of Rheological Parameters for Herschel-bulkley Drilling Fluids Using Genetic Algorithms (GAs),” Korea-Australia Rheology Journal, 2012, 24(3), 163-170.

Kelessidis V. C., Maglione R., Tsamantaki C., and Aspirtakis Y., “Optimal Determination of Rheological Parameters for Herschel–Bulkley Drilling Fluids and Impact on Pressure Drop, Velocity Profiles and Penetration Rates during Drilling,” J. Pet. Sci. Eng., 2006, 53, 203-224.

Herschel W. H. and Bulkley R., “Konsistenzmessungen Von Gummi-Benzollosungen,” Kolloid-Z., 1926, 39, 291-300.

Robertson R. E. and Stiff H. A., “An Improved Mathematical Model for Relating Shear Stress to Shear Rate in Drilling Fluid and Cement Slurries,” SPE J., 1976,16, 31-36.

Gucuyener I. H., “A Rheological Model for Drilling Fluids and Cementing Slurries,” paper SPE 11487 Presented at the Middle East Oil Technical Conference, Manama-Bahrain, Soc. Pet. Eng., 1983, 389–386.

Papanastasiou T. C., “Flows of Materials with Yield,” J. Rheology., 1987, 31, 385-404.

Alderman N. J., Gavignet A., Guillot D., and Maitland G. C., “High-Temperature, High-Pressure Rheology of Water-Base Mud,” SPE 18035, Houston, TX, 1988, 187-195.

Khataniar S., Chukwa G. A., and Xu H., “Evaluation of Rheological Models and Application to Flow Regime Determination,” J. of Petroleum Science and Engineering, 1994, 11, 155-164.

Davison J. M., Clary S., Saases A., Allouche M., and et al., “Rheology of Various Drilling Fluid Systems under Deepwater Drilling Conditions and the Importance of Accurate Predictions of Downhole Fluid Hydraulics,” SPE 56632, presented at the SPE Annual Technical Conference and Exhibition held in Houston, Texas, 1999, 1-13.

Pilehvari A., Serth R., and Largad V., “Generalized Hydraulic Calculation Method Using Rational Polynomial Model,” SPE 71403, presentation at the SPE Annual Technical Conference and Exhibition held in New Orleans, Louisiana, 2001, 1-13.

Zamora M. and Power D., “Making a Case for AADE Hydraulics and the Unified Rheological Model,” Paper AADE-02-DFWM-HO-13 Presented at the AADE Technical Conference, Houston, 2002.

Versan M. and Tolga A., “Effect of Polymers on the Rheological properties of KCl/Polymer Type Drilling Fluid,” Energy Sources, 2005, 27, 405-415.

Wang F., Tan X., Wang R., Sun M., and et al., “High Temperature and High Pressure Rheological Properties of High-density,” Pet. Sci., 2012, 9, 354-362.

Bui B. T., and Tutuncu A. N., “A Generalized Rheological Model for Drilling Fluids Using Cubic Splines,” SPE-169527-MS, presentation at the SPE Western North American and Rocky Mountain Joint Meeting, Denver, Colorado, 2014, 1-13.

Neshat J. and Shadizadeh S. R., “Evaluation of a Naturally-derived Deflocculant (Terminalia Chebula) in Bentonite Dispersions,” Iranian Journal of Oil & Gas Science and Technology, 2016, 5(2), 21-44.

Ahmadi M. A., Shadizadeh S. R., Shah K., and Bahadori A. R., “An Accurate Model to Pedict Drilling Fluid Density at Wellbore Conditions,” Egyptian Journal of Petroleum, 2018, 27, 1-10.

Rabia H., “Well Engineering & Construction,” Entrac Consulting Limited, 2002, 242-245.

American Petroleum Institute (API), “Recommended Practice on the Rheology and Hydraulics of Oil-Well Drilling Fluids,” API RP13D (4th ed.), Washington, USA, 2009.

Feys D., Verhoeven R., and De Schutter G., “Evaluation of Time Independent Rheological Models Applicable to Fresh Self-compacting Concrete,” Appl. Rheol., 2007, 17(5), 56244-1 –56244-10

Chatzimina M., Georgiou G., and Alexandrou A., “Wall Shear Rates in Circular Couette Flow of a Herschel-Bulkley Fluid,” Appl. Rheol., 2009, 19(3), 34288.

Kelessidis V. and Maglione R., “Shear Rate Corrections for Herschel-Bulkley Fluids in Couette Geometry,” Appl. Rheol., 2008, 18(3), 34482-1–34482-11

Power D. and Zamora M., “Drilling Fluid Yield Stress: Measurement Techniques for Improved Understanding of Critical Drilling Fluid Parameters,” paper AADE-03-NTCE-35 Presented at the AADE Technical Conference, Houston, 2003.

Shah S. N., Narayan P. E., Shanker H., and Chinenye C., “Future Challenges of Drilling Fluids and Their Rheological Measurements,” AADE-10-DF-HO-41, AADE Fluids Conference and Exhibition Held at the Hilton Houston North, Houston, Texas, 2010, 1-15.

American Society of Mechanical Engineers (ASME), “Shale Shaker Committee,” Drilling Fluids Processing Handbook, Elsevier Inc, 2005.

Goodarznia I. and Esmaeilzadeh F., “Treatment of Oil-contaminatment Drill Cuttings of South Parts Gas Field in Iran Using Supercritical Carbon Dioxide,” Iranian Journal of Science & Technology, Transaction B, Engineering, 30 (B5), 2006.

Sedaghatzadeh M., Fazel Abdulabadi B., and Shahbazi K., “Thermal and Rheological Properties Improvement of Oil-based Drilling Fluids Using Multi-walled Carbon Nanotubes (MWCNT),” Journal of Petroleum Science and Technology, 2016, 6(2), 37-44.

Myttenaere A., Golden B., Grand B., and Rossi F., “Using the Mean Absolute Percentage Error for Regression Models,” European Symposium on Artificial Neural Networks, Computational Intelligence and Machine Learning (ESANN), Belgium, 2015.