Optimization and Process Modeling of Viscosity of Oil Based Drilling Muds

Azinta Cyprian Obinna, Gordian O. Mbah, Maxwell I. Onoh


The viscosity of oil-based drilling mud was optimized and modeled in this study. Imported bentonite and local clay additives, and diesel oil (base fluid) were used to prepare two muds; oil-based mud with bentonite (OBMB) and oil-based mud with clay (OBMC). The local clay was beneficiated with hydrochloric acid (HCl) and then characterized using an x-ray fluorescence (XRF) spectrometer. The result of the characterization revealed that the local clay is more of silica (SiO2) which is typical of a kaolin. The interactive effects of three operating conditions, temperature, aging time, and bentonite/clay dosage, respectively, on the viscosity of each mud were determined. The Response surface methodology (RSM) of the central composite design tool of Design Expert software (version 12) was employed to optimize the viscosity of each mud. The RSM carried out revealed the interaction between the three operating variables of temperature, time, and dosage of bentonite/clay and their impact on the viscosity of each mud. Optimum viscosity of 19.3  for OBMB and 25.9 for OBMC were obtained at temperature of 313K, aging time of 30 minutes and bentonite/clay dosage of 9 wt%. Analysis of variants (ANOVA), mathematical modeling, and graphical plots further established the actual interaction between the response-viscosity of each mud and the considered process factors. The generated models revealed linear, interactive, and quadratic equations which adequately described the relationship between the viscosity of each mud and the considered factors of temperature, time, and dosage. The experimental data and the predicted results were compared, and the model predicted values are in good agreement with the experimental results.


Doi: 10.28991/HEF-2021-02-04-09

Full Text: PDF


Bentonite; Local Clay; Optimization; Quadratic Model; Response Surface Methodology; Viscosity; Rheological Properties.


Zhuang, G., Zhang, Z., Fu, M., Ye, X., & Liao, L. (2015). Comparative study on the use of cationic-nonionic-organo-montmorillonite in oil-based drilling fluids. Applied Clay Science, 116–117, 257–262. doi:10.1016/j.clay.2015.04.004.

Charles, O., & Adetokunbo, F. (2017). Comparative Study of the Rheological Properties of Local Clay (Afuze) as a Possible Replacement for Imported Bentonite in Drilling Fluids Formulation. International Journal of Scientific & Engineering Research, 8(11), 249–255.

Omotioma, M., Ejikeme, P. C. N., & Ume, J. I. (2015). Improving the rheological properties of water based mud with the addition of cassava starch. IOSR Journal of Applied Chemistry, 8(8), 70–73.

Azinta, C. O., Mbah, G. O., & Omotioma, M. (2021). Analysis of Effects of Foreign Clay and Local Clay Additives on Viscosity of Water Based Drilling Mud. Journal of Engineering Research and Reports, 21(4), 60–67. doi:10.9734/jerr/2021/v21i417459.

Kassab, S. Z., Ismail, A. S., & Elessawi, M. M. (2011). Drilling fluid rheology and hydraulics for oil fields. European Journal of Scientific Research, 57(1), 68–86.

Yunita, P., Irawan, S., & Kania, D. (2016). Optimization of Water-based Drilling Fluid Using Non-ionic and Anionic Surfactant Additives. Procedia Engineering, 148, 1184–1190. doi:10.1016/j.proeng.2016.06.628.

Amani, M. (2012). The Rheological Properties of Oil-Based Mud under High Pressure and High Temperature Conditions. Advances in Petroleum Exploration and Development, 3(2), 21–30. doi:10.3968/j.aped.1925543820120302.359.

Gusler, W., Pless, M., Maxey, J., Gorver, P. E., Perez, J., Moon, J., & Boaz, T. (2007). A new extreme-HP/HT viscometer for new drilling-fluid challenges. In SPE Drilling and Completion (Vol. 22, Issue 2, pp. 81–89). doi:10.2118/99009-pa.

Murtaza, M., Alarifi, S. A., Kamal, M. S., Onaizi, S. A., Al-Ajmi, M., & Mahmoud, M. (2021). Experimental Investigation of the Rheological Behavior of an Oil-Based Drilling Fluid with Rheology Modifier and Oil Wetter Additives. Molecules, 26(16), 4877. doi:10.3390/molecules26164877.

Huang, Y., Zheng, W., Zhang, D., & Xi, Y. (2019). A modified Herschel–Bulkley model for rheological properties with temperature response characteristics of poly-sulfonated drilling fluid. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 42(12), 1464–1475. doi:10.1080/15567036.2019.1604861.

Keshavarz Moraveji, M., Ghaffarkhah, A., Agin, F., Talebkeikhah, M., … Arjmand, M. (2020). Application of amorphous silica nanoparticles in improving the rheological properties, filtration and shale stability of glycol-based drilling fluids. International Communications in Heat and Mass Transfer, 115, 104625. doi:10.1016/j.icheatmasstransfer.2020.104625.

Martín-Alfonso, M. J., Mejía, A., Martínez-Boza, F. J., & Martín-Alfonso, J. E. (2021). Rheological characterization of sepiolite-vegetable oil suspensions at high pressures. Applied Clay Science, 212, 106220. doi:10.1016/j.clay.2021.106220.

Makinde, F. A., Adejumo, A. D., Ako, C. T., & Efeovbokhan, V. E. (2011). Modelling the effects of temperature and aging time on the rheological properties of drilling fluids. Petroleum and Coal, 53(3), 167–182.

Abduo, M. I., Dahab, A. S., Abuseda, H., AbdulAziz, A. M., & Elhossieny, M. S. (2016). Comparative study of using Water-Based mud containing Multiwall Carbon Nanotubes versus Oil-Based mud in HPHT fields. Egyptian Journal of Petroleum, 25(4), 459–464. doi:10.1016/j.ejpe.2015.10.008.

Apugo-Nwosu, T. (2011). Studies on the Suitability of Ubakala Bentonitic Clay for Oil Well Drilling Mud Formulation. British Journal of Applied Science & Technology, 1(4), 152–171. doi:10.9734/bjast/2011/407.

Allawi, R. H., Najem, M. A., Sagger, M. A., & Abd, S. M. (2019). Effect of Temperature on Drilling Mud. Journal of Physics: Conference Series, 1279(1), 012054. doi:10.1088/1742-6596/1279/1/012054.

Kinate, B. B., & Dune, K. K. (2016). Comparative study of the rheological properties of Niger Delta crude oil Journal of Scientific and Engineering Research, 3(6), 323.

Samuel Ogbonnaya, E., Gordian Onyebuchukwu, M., & Ebere Rita, M.-I. (2018). Optimization And Process Modeling Of The Extraction Of Alumina From Aku Clay By Hydrochloric Acid Leaching. American Journal of Engineering Research (AJER, 7(7), 158–169.

Oyegoke, T. (2013). Optimization of Rheological and Filtration Properties of Nigeria Clay using Factorial Design. International Journal of Innovative Scientific & Engineering Technologies Research, 1(1), 25–36.

Azinta, C. O. (2021). Comparative analysis of effects of bentonite and Awgu clay additives on the rheological properties of oil and water based drilling muds. Master’s Thesis, Chemical Engineering Department, Enugu State University of Science and Technology, Enugu, Nigeria.

Li, M.-C., Wu, Q., Lei, T., Mei, C., Xu, X., Lee, S., & Gwon, J. (2020). Thermothickening Drilling Fluids Containing Bentonite and Dual-Functionalized Cellulose Nanocrystals. Energy & Fuels, 34(7), 8206–8215. doi:10.1021/acs.energyfuels.0c01192.

Full Text: PDF

DOI: 10.28991/HEF-2021-02-04-09


  • There are currently no refbacks.

Copyright (c) 2022 Azinta Cyprian Obinna, Gordian O. Mbah, Maxwell I. Onoh