This paper overviews the design, development, qualification, and field trial deployment of a hydraulically expandable metal packer that enabled a cementless, zonal, high-pressure acid stimulation program to be accomplished.
Achieving effective zonal isolation within long reach horizontal wells using conventional means with cement is challenging to the industry. Achieving effective cement within long step outs is limited by the Equivalent Circulation Density (ECD) (impacted by fracture/pore pressure) or by the inability to achieve effective cement (i.e., without channels/micro annuli) simply due to the sheer length of the horizontal section of the well. Additional challenges are then imposed to achieve zonal isolation within unconventional reservoirs or wells that require high-pressure stimulation.
These challenges spurred the design for a metal expandable packer for use in a cementless completion, assembled on a full bore liner, and able to deliver a high annular Delta P seal in a worse case washed-out hole scenario.
Material selection to allow hydraulic expansion beyond the yield point of the expanding alloys (i.e., in the plastic region) is a key design consideration for maximizing the post-expansion strength of the expandable metal packer. Continual design, test, and result analysis enabled development of a unique, high-pressure seal between the metal expansion sleeve and the formation. The qualification process was based on the ISO 14310 V3 standard, the industry standard for testing and qualifying plugs and packers. This standard emulates the lifecycle of the packer during acid stimulation and later-life water management.
Field-proven zonal pressure isolation will be illustrated with real-time zonal pressure data from the field trial in an offshore field. The well will demonstrate cement-less liner completion efficiency with sixteen expandable metal packers to achieve five isolated, stimulated, and subsequently producing zones and three water shut-off zones.
In closing, the paper will summarize ongoing developments and how the open hole expandable metal packer is meeting the unique challenges of annular high-pressure containment. The many benefits to operators include fast setting under surface control with increased reliability and certainty for success.