Project Overview
Communication between the ocean and the annulus was observed on Chevron’s Wheatstone platform, so corrosion mitigation was critical to maintaining both the J-Tubes structural capacity in the high current environment and its integrity as it passes through some critical tanks.
Technip contracted us to engineer, test and deliver the solution to Chevron. The scope included design and qualification testing for the reversible plug. We built a full-scale mock-up of the J-Tube and umbilical at our Henderson facility.
MMA's Solution
We designed the slurry mix to be mixable and pumpable for a 30-year design life and ensure compatibility with the umbilical and J-tube. We used high bentonite content to increase the design life as it does not degrade over time.
We used our SGM2000 mixing unit to batch the mix on the platform and pump it in the annulus. A range of leak paths up to 25mm in diameter, including steel armour wiring, was created and demonstrated to be sealed.
We also conducted thermal load testing of the mock-ups to determine the effects of heat on shrinkage and conductivity.
Outcome
The project resulted in a reversible annulus plug mix to eradicate the corrosion issues on Chevron’s Wheatstone platform.