A 20/80 Oil/Water Ratio Nonaqueous Screen Running System Successfully Employed In Equatorial Guinea

Abstract

An innovative surfactant chemistry in a nonaqueous system with an oil-to-water ratio (OWR) of 20/80 was effectively utilized for the first time to provide wellbore stability and run a sand-control screen in an openhole gravelpack completion. This novel type of invert emulsion system uses relatively higher aqueous internal phase, i.e., less than 50/50 OWR, which subsequently allows for a relatively higher density than the drilling fluid. More importantly this system is maintained as solids free and oil continuous.The increasing application of Inflow Control Devices/Intelligent Wellbore Systems and swellable elastomers as well as drilling longer intervals and their exposure to shale/sand dictates the use of compatible and solids-reduced invert systems to reduce the risk of an unsuccessful gravel placement treatment caused by shale swelling or plugging of sand control screens. This novel high-internal phase system provides flexibility for these types of completions. The use of the higher internal phase allows the formulation of oil-continuous solids-free systems while still achieving the required density necessary in solidsladen aqueous systems. This paper will focus on the selection of the 20/80 high-internal-phase system for this openhole completion, the upfront testing and planning for deployment. Discussion will also be provided with respect to the mixing of the system at the wellsite as well as the lessons learned.

A Case Study Using a Remotely Controlled Downhole Valve for Completion Installation

“…(Weaver, R.A. et al, 2002) Located in approximately 700 m of water and in one of six subsea clusters in the development, this well was identified as a suitable candidate for the inclusion of the technology outlined in this paper. To maximize reservoir recovery in this field, the completion strategy included a horizontal openhole gravel pack to provide downhole sand control (Paz, Lim et al 2013). The completion engineers felt that this strategy would help meet the production objectives such as inflow performance; however, it also would require the well to be drilled at a highly deviated trajectory, which would increase the likelihood of the production packer being set at a deviation beyond conventional slickline capability.…”