FoundOcean Projects BLOG

To rectify this, a donut-shaped fabric formwork bag was placed around the mudmat at the bottom of each leg and filled with grout. The void between the mudmat and the seabed was then grouted to act as a plug before filling the leg with grout to further strengthen it. This was carried out on each of the four corner legs.

Wednesday 29th December
The FoundOcean crew arrived in Great Yarmouth to board the Seven Atlantic today. The Seven is quite a modern vessel and we comfortably settled to our new surroundings. We steamed out to the North Sea and the vessel resumed its position beside the Clipper PT Platform.

Thursday 30th December
Following the safety meeting and a briefing with Subsea 7 and Shell, all 8 FoundOcean crew worked a single shift today. The grouting equipment and plant was set up and valve assemblies were prepared for grouting operations. A function test was carried out on the primary and secondary grout mixers using seawater. To cover the possibility of high pressure in the grout hoses it was decided that cold work permits were to be in place to cover each 12 hour shift. Colin Barrett (Supervisor) and his crew were to work day shifts and James Ramsay (Mixer driver), Thomas McPake (Lab Technician), Richard Graham (Mechanic) and I were to work the night shifts – from midnight to midday.

Friday 31st December
Weather conditions were favourable for grouting with relatively calm seas. After flushing grout lines and connecting up the various hoses, grout bag A1 was successfully completed. Preparation of mixer and grouting equipment before grouting operations proved to be paramount as the divers had a limited tidal window with spring tides in force. Because of this it was important for the grouting team to be prepared and ready to start work as soon as this window became available.

The Clipper platform	Offshore personnel in their survival suits	The helipad

Saturday 1st January
Mudmat A1 void was completed during the early hours of New Year’s Day. We pumped 2.35m3 of quality grout to the void and achieved the required specific gravity of 1.98. Pumping stopped later that morning at 06:37hrs by which time the operation was completed and accepted by Subsea 7. The purpose of grouting the mudmat void is to act as a plug to seal the lower end of the leg annulus. For the rest of our shift the crew and I remained on standby and carried out general maintenance to the plant.

Sunday 2nd January
Mudmat Void C2 was the foremost operation during the early hours of Sunday morning. After pumping a cubic metre over the theoretical volume it was decided to halt grouting operations. Because of the shallow waters and heavy swell, seawater was surging in and out of the mudmat void causing grout to be sucked out. Operations halted at 02:30 with a view to completing the void over the following days.

Monday 3rd January
As a result of heavy swell the problem with surging water postponed grouting operations. The crew and I carried out routine maintenance to the plant and remained on standby for the remainder of our shift.

Tuesday 4th January
Leg annulus A1 was successfully grouted and completed between 02:00 and 05:00 on Tuesday morning. A total volume of 1.77m3 was pumped into the annulus by which time good returns were overflowing from the leg valve, and confirmed by Subsea 7 divers.

Wednesday 5th January
During this night shift, the crew managed to grout mudmat void A2. After flushing and connecting up the grout hose we pumped 1.88m3 into the mudmat void until good returns were confirmed. The Seven Atlantic steamed back into Great Yarmouth in order to take on a new marine crew. After completing this we resumed our position beside the Clipper rig later that evening. The cube samples from the previous night were weighed, measured and crushed.

The Clipper platform	The Clipper platform	The spread on board the vessel

Thursday 6th January
This was the final grouting operation for the night shift crew. We started pumping grout into leg C1 at 04:00 hrs. Because of a small technical issue with the 12V batch mixer Colin, the FoundOcean Supervisor, implemented a contingency procedure. He decided we should use the smaller 10V backup mixer to complete the grouting operation but because of the tight tidal window we mixed the grout in the 10V and pumped it to the 12V holding tank. This was because the pump on this machine has a higher output and as a result, the reduced pumping time allowed the operation to be completed during the acceptable tidal period. We completed leg C1 successfully and stopped pumping at 05:00hrs. General maintenance was carried out to plant and we remained on stand-by until shift handover at midday.

Friday 7th January
Today, the crew tried to get back into normal sleeping patterns. The majority of the work today was cleaning down the deck and de-rigging the grouting equipment. Cement lines were rolled up and placed into the storage container, grout hoses were reeled in, the storage container was tidied and work benches were cleaned, pressure was released from silos, cubes were crushed and results were recorded, open vents from silos were sealed, and many other tasks were carried out in order to get the equipment prepared for demobilization.

Saturday 8th January
The debriefing was held with Subsea 7 and Shell. They were happy with the grouting operations by FoundOcean personnel and “hoped to see us again soon!”  A helicopter landed on the Seven Atlantic’s heliport at midday. All FoundOcean personnel embarked and flew back over the choppy North Sea to Norwich.