The Development and Field Performance of a Novel Open Hole Packer System for Deep Water, High Rate, Water Injection Wells With Down Hole Flow Control. A Deep Water Field Case History

Abstract

Greater Plutonio is a 5 field subsea, deepwater project, located offshore Angola. Development began in 2005 and 38 wells have now been completed in highly permeable but poorly consolidated Oligocene reservoirs. Production commenced in October 2007 and is supported by injection of over 350mbd of water into 21 water injectors, predominantly completed with Stand Alone Screens. As the fields have multiple stacked reservoirs, dual zone downhole flow control (DHFC) is advantageous in many water injectors as it allows better control of injection conformance and / or a reduction in well count. During the design phase, it was recognized that although much of the hardware for DHFC systems for water injectors was field proven, the ability to create a long term seal between zones with openhole completions, especially in the deepwater environment, was a significant challenge that had not yet been addressed by the industry. The key challenges were: High differential pressure rating (3000psi). Achieve a robust seal in non-circular wellbores. Large axial load resulting from temperature reduction and differential pressure (>400,000lbs). Large number of injection and shut-in cycles occur over life of well. Large changes in temperature and consequently axial loading occur with each cycle. Following a technical evaluation, a novel dual cup packer concept with integral sliding movement joint and openhole packer slips was selected. This was followed by a 2.5 year rigorous design and qualification period prior to field installation1. 8 DHFC water injection wells have now been installed in Greater Plutonio, and downhole pressure data shows that the cup packers are providing robust high pressure seals after 3.5 years of high rate water injection. The cup packer system has produced a step change in openhole packer technology that has facilitated installation of reliable DHFC water injection wells at scale in the deepwater environment.