A new, high-expansion sealing device uses expanding metal in place of elastomers to form a high-integrity pressure seal on the tubular wall. Baker Oil Tools developed the metal-to-metal, high-expansion Z-Seal technology to increase the capability of its downhole equipment to provide pressure integrity, particularly in hostile, high-pressure/high-temperature (HP/HT) environments. The seal is made entirely of metal, making it highly insensitive to temperature failure modes and able to withstand high-pressure forces.

Because it contains no elastomers, the seal dramatically improves downhole equipment performance in many well intervention applications and makes intervention possible in hostile well environments previously deemed inoperable. The metal seal expands to up to 160% of its original size while maintaining true HP/HT performance. It also uses applied differential pressure to exert additional self-energizing load to reinforce the seal. The seal system can be fully retracted in applications that require tool retrieval. Eliminating elastomers also dramatically improves downhole equipment performance by eliminating conventional failure modes such as temperature or chemical degradation, fatigue and shearing.

The technology offers many additional advantages, including a lower profile, smaller OD for protection from mechanical damage, easier retrieval and less debris, chemical and gas resistance, and conformance to irregular bore shapes. Initial applications of Z-Seal technology in bridge plugs and straddle assemblies have proven the technology and the potential of the products in the well-servicing market. The seal technology is currently being used as a medium- to high-expansion solution for bridge plugs, straddle systems and flow-control devices.