A Novel Invert Emulsion System Using a Polyglycerol Internal Phase

Authors T. Allen (Ultra Petroleum) | K. Scott (Ultra Petroleum) | S. Baker (Ultra Petroleum) | M. Redburn (Newpark Drilling Fluids) | M. Bechaver (Newpark Drilling Fluids) | H. Dearing (Newpark Drilling Fluids) | E. Ward (Newpark Drilling Fluids) | D. Chamberlain (Newpark Drilling Fluids)
Document ID OMC-2015-382
Publisher Offshore Mediterranean Conference
Source Offshore Mediterranean Conference and Exhibition, 25-27 March, Ravenna, Italy
Publication Date 2015

Abstract

Invert-emulsion systems, which have been used since the 1950’s, consist of a continuous oil phase and an aqueous internal phase. The aqueous internal phase typically consists of a calcium chloride brine solution. In this paper it was found that a polyglycerol additive led to consistent trends of increased rates of penetration (ROP), reduced stick-slip, and improved wellbore stability. This paper verifies that the novel polyglycerol acts as a water-activity control agent and functions better than a calcium chloride invert-emulsion drilling fluid.

This water activity control agent is a proprietary blend of polyglycerols with low alkalinity and is completely soluble in water and brines. This innovative additive minimizes wellbore shale hydration by optimizing the water phase’s activity. The additive strengthens the wellbore and inhibits fluid interactions with formation clays. The additive also reduces the coefficient of friction, which increases ROP and reduces torque and drag in high-angle wellbores. Reducing axial and rotational stick-slip allows for prolonged bit and tool life, resulting in more time on bottom drilling and less time tripping. The cumulative performance improvements reduce total well costs.

This paper discusses an on-going, seven-year, field application in the Rocky Mountains of this novel invert-emulsion drilling fluid system. Results improved over time and led to optimized operational efficiencies.