FACILITATING MUD DESIGN, CEMENTING JOB DESIGN AND THE ENTIRE DRILLING OPERATIONS BY MODELLING THE RHEOLOGICAL PROPERTIES OF WATER-BASED MUD AND OIL-BASED MUD WITH TEMPERATURE

Abstract

The increasing rental cost of a drilling Rig and the associated painful cost of downtime when drilling oil & gas wells, are some of the major concerns of Oil & Gas Companies. Improper rheological properties of drilling mud may cause a variety of problems including insufficient cuttings transport, limited solids suspension, poor hole-cleaning and excess filtrate loss into the formation. Facilitating mud design, cementing job design and the entire drilling operation will save Rig time and associated cost and prompt management of Oil & Gas Companies to devote more of their useful time and resources to other significant aspects of their operations. The aforesaid prompted this work, on developing mathematical models representing the rheological parameters of drilling mud (water-based mud and oil-based mud) to enable prediction of the rheological properties in emergency situations where and when Laboratory services are not immediately available. The methods applied include Laboratory testing and mathematical modeling. Results revealed that mathematical models can be confidently applied to predict variation of the Plastic viscosity and Yield stress of water-based mud and oil-based mud with temperature as the correlation coefficient (R-squared value) obtained for each of the aforesaid rheological properties was higher than 95%. Therefore, as the rheological properties of water-based mud and oil-based mud also depend on their composition, chemical properties and other physical properties, mathematical models representing the variation of Plastic viscosity and Yield stress with temperature, should be proactively developed for every mud in hole to enable their prediction in emergency situations especially when and where laboratory services are not immediately available.