Developing a Thermally Stable Ester-Based Drilling Fluid for Offshore Drilling Operations by Using Aluminum Oxide Nanorods

Alaa Ahmed, Amin Sharifi Haddad* (Corresponding Author), Roozbeh Rafati, Ahmed Bashir, Ahmed M. AlSabagh, Amany A. Aboulrous

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)
4 Downloads (Pure)


Esters were found to be promising alternatives to oil, as a constituent of drilling fluids, due to their biodegradability and bioaccumulation attributes. In this study, we used ethyl octanoate ester (EO) as a low molecular weight synthetic oil for formulating an ester-based drilling fluid (EBDF). Aluminum oxide nanorods (nanoparticles) were introduced as a Pickering emulsion stabilizer. Like the commercial emulsifiers, they showed that they stabilized the invert emulsion drilling fluid in our study. The rheological and filtration properties of the EBDF were tested at normal pressure and three temperatures: low temperature deepwater (LT) conditions of 2.6 °C, normal pressure and normal temperature (NPNT) conditions of 26.8 °C, and elevated temperature conditions of 70 °C. To enhance the stability and filtration properties of the drilling fluid, aluminum oxide nanoparticles (NPs) were used. An optimum concentration of 1 wt% was found to provide superior rheological performance and higher stability than samples without NPs at NPNT, LT, and elevated temperature conditions. Steadier gel rheology was exhibited at elevated temperature conditions, and a slow rate of an increasing trend occurred at the lower temperatures, with increasing NP concentrations up to 1.5 wt%. Filtration loss tests presented a reduction of fluid loss with increasing the NP concentration. The results demonstrate that a reduction of up to 45% was achieved with the addition of 1 wt% NP. These results show that nano-enhancement of ethyl octanoate drilling fluids would suffice to provide a wider range of operational temperatures for deepwater drilling operations by providing better thermal stability at elevated temperatures and maintaining stability at lower temperatures.
Original languageEnglish
Article number3399
Number of pages18
Issue number6
Early online date19 Mar 2021
Publication statusPublished - 19 Mar 2021

Bibliographical note

Funding: This work was supported by an Institutional Links grant, ID 352343681, under the Newton–Mosharafa Fund partnership. The grant is funded by the UK Department for Business, Energy and Industrial Strategy, and Science, Technology & Innovation Funding Authority (STDF) and delivered by the British Council. For further information, please visit Science,
Technology & Innovation Funding Authority (STDF) support was under the grant No. (30894).
Acknowledgments: The authors would like to acknowledge the School of Engineering at the University of Aberdeen for providing the required facilities to complete this research. In addition, the authors would like to thank the support from MI-SWACO in providing commercial emulsifiers and consumables used in this project.


  • ester-based drilling fluid
  • ethyl octanoate
  • low temperature
  • nanoparticles


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