101New Generation Glycol Drilling Fluids System for Drilling of Water-Sensitive Formations


Abstract:

Intensified concerns about hazardous environmental effects of conventional oil-based mud (OBM) in Iranian offshore oil fields motivated drilling companies in Iran to search for a suitable substitution.  Water based drilling fluid (WBDF) is relatively a qualified class of drilling fluids that can combine the technical advantages of OBM. Glycol is a type of water fluid and is counted as one of the highest prospects for extensive use in Iran due to its availability and lower cost, compared to other types of drilling fluids.

In this study, feasibility of utilizing innovative formulations of water based drilling fluid (WBDF) was investigated mostly based on local products. Suitable formulations for PBM at desired operational ranges of temperature, mud weight and glycol and water ratio (G/W) were developed and optimized. In addition, Rheological properties and electrical stability of the systems were measured. Stability of each mud system under down-hole conditions was examined and their filtration characteristic was determined by means of a filter press. Furthermore, Shale recovery was evaluated and the effects of possible contaminants in the system were also studied. Confirmation of the obtained results was conducted by comparison of Glycol-based mud with similar conventional oil based packages.

From technical points of view, laboratory results indicate that conventional muds can be replaced with Glycol-based mud in Iranian offshore fields since it suppresses environmental concerns, is tolerable to contaminant and can provide advantages of OBM with reasonable cost. Comparisons of WBM with OBM show that rheological properties and shale recovery were approximately identical, while Glycol based mud represented higher electrical stability and lower filtration rate.

Keywords:  Glycols, water based drilling fluid (WBDF), Shale Inhibition, Lubricity, Reactive Shale.

PDF Format of Article

References:

  • Lal, N., “Shale Stability: Drilling Fluid Interaction and Shale Strength”, SPE 54356, 1999. Presented at the SPE Latin American and Caribbean Petroleum Engineering Conference held in Caracas, Venezuela, 21–23 April.

  • M-I Fluid Company, “M-I Drilling Fluid Engineering Handbook”, 2001, Version 2, Chapters 5, 11, 12 and 13.

  • Amoco Production Company, 2004, “Drilling Fluids Manual”, electronic version, Published by AMOCO Production Company.

  • Valenziano, R., Harris, K.L., Dixon, M.D., 2009. Servicing a wellbore with an aqueous based fluid comprising a clay inhibitor. US Patent 7 549 474, assigned to Halliburton Energy Services, Inc.(Duncan, OK), June 23 2009.

  • Aston. M. S., Exploration BP, and Elliott. G.P.,BP Chemicals., “Water Based Glycol Drilling Muds: Shale Inhibition Mechanisms” SPE 28818, 1994.

  • Darely, H. C., G. R., Gray, Fifth Edition 1988, “Composition and Properties of Drilling and Completion Fluids”, Published by Gulf Professional Publishing.

  • Burrows, K., J. Evans, J. Hall, J. Kirsner, “New Low Viscosity Ester Is Suitable for Drilling Fluids in Deepwater Applications”, Baroid Drilling Fluids, SPE 66553, 2001.

  • Darely, H. C., G. R., Gray, Fifth Edition 1988, “Composition and Properties of Drilling and Completion Fluids”, Published by Gulf Professional Publishing.

  • Friedheim, J.E., A., Patel, “Technical Solutions for Environmental Problems: Novel Drilling Formulations to Minimize Environmental Impact”, SPE 52741 1999. Presented at SPE/EPA Exploration and Production Environmental Conference, Austin, TX, 28 February-3 March 1999.

  • Van Oort, E., 1997. Physico-chemical stabilization of shales, in: Proceedings Volume, SPE Oilfield Chem. Int. Symp. (Houston, 2/18–21/97), pp. 523–538.