Project Overview
The South Nemba A jacket is an 8-leg jacket with 8 skirt piles in the Chevron-operated, Block 0 offshore Angola. Following an annual subsea inspection, cracks were discovered in critical jacket structural members.
Our client Oceaneering specified an external clamp repair project to restore full capacity to the jacket. Critical to the success of this solution was a strong connection between the clamps and the jacket. We collaborated with Oceaneering on a grouted solution for load transfer between the clamps and the jacket braces.
MMA's Solution
For the annulus grouting, we developed a high-performance structural grout based on seawater and ordinary Portland cement, the SG was 1.92 and the characteristic compressive strength was 56MPa after 28 days.
We supplied our barge-based CM2000 jet mixer with constant density monitoring and silo fed cement for dust-free, reliable grout delivery to five clamps on the jacket legs.
The campaign ran for over six months and involved remote operations by MMA crew working from the Dive Support Vessel Topas Commander.
Technical Details
| Number of Clamps |
5 |
| Grout Speciifc Gravity |
1.92 Te.m3 |
| Characteristic Strength |
56MPa at 28 days |
| Total Volume |
50m3 |
Key Equipment / Installation Method
MMA Innovation / Value Added
We designed and qualified a highperformance grout mix design based on seawater and GP cement. The use of locally available materials minimised international and offshore logistics typically associated with imported pre-packaged grouts and the supply of freshwater.
Our semi-automatic batching unit CM2000 supplied grout at up to 16m3/hr minimising the offshore construction schedule timeline to ensure logistics efficiency.