Releasable and reusable mooring system

Something for the hurricane prone Gulf of Mexico?:

Interesting concept. I find this logic a little strange though:

no need to pay daily rates for the anchor handling vessels. All we needed were a couple of boats to recover the mooring system, consisting of between 1000 and 1500 metres of round chain, 800 to 1200 metres of fibre rope and an 18t STEVPRIS MK6 anchor for each mooring line.”

How can you say there is no need for anchor handling vessels and then say all you need are a couple vessels to handle the anchors?

Sure, you don’t need the vessels standing by before the storm or at EOW to pull anchors so you can run or transit, it can be done later. (The cynic in me sees this just as a way for the Company Man to push for continuing work during an approaching storm and delay disconnect since T-Time is reduced). But you still need to spend time when ready to re-deploy anchors for those non-anchor handling vessels to apparently pull up all the mooring equipment, reconnect to the RAR System, and then re-deploy the anchors.

They don’t go into the re-connection details details, but I guess if the rig can pay out their end of the RAR system connection to the support vessel, and if the support vessel can recover the anchor-end of the RAR system and make the re-connection on their deck, then sure, this would save a ton of time.

Yes they will still need anchor handling vessels, but it just makes this a bit more efficient, with rig moves any time savings can lead to big financial savings.

Spot market rates for AHVs might be high when they need to move the rig, now they can just disconnect it and move the rig without an AHV then they can wait for spot market rates to drop to hire an AHV to recover the mooring system.

But not good news for AHV operators as their vessels will be needed less.

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Rigs in the North Sea, (or as here in the Norwegian Sea), does not normally move away from location during storms, even of hurricane force.

What they are talking about here is time and money saved by being less weather dependent during planned move on and especially off location.
Rig time is costly and being able to disconnect in any weather can save some serious money.
Doing so without the need to bring in AHV from the spot market just add to the cost savings.

As Ladder point out AHVs are expensive, especially in good weather periods in Autumn/Winter season, when several operators may compete for their service.

I the case of Deepsea Stavanger mentioned the drilling location was in the Norwegian Sea, not far from the Offshore Base in Kristansund. The mooring system was pre-set by two large AHVs (>270 t.BP) operating from there well in advance of the arrival of the rig from a base near Bergen. (Self-propelled. not towed or tug assisted)

PS> What they didn’t mention is that one AHV was left on location for several days to guard the mooring system from any fishing vessels hooking their longlines/nets/trawl onto the moorings… (No surface buoys)

For the hook-up three more large AHVs were brought in from the spot market. (They were mobilized from Bergen, Stavanger, or maybe Aberdeen).

PS>While on location the rig was attended by an EERV and a PSV from the base in KRS.

It was a short drilling campaign. After some 3 weeks the rig disconnected and moved to it’s next drilling location w/o AHV, or tug assistance.

Looking at the cluttered deck of one of the AHV you can see it is not a simple operation:

But well worth it for operations off Norway in Dec-Jan… when the Lows comes one after the other, “like pearls on a string”.

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In a lot of cases the mooring lines wouldn’t need to be reconnected because the rig would have completed its drilling program at that location, they just release the line and move off location.

If they did need to reconnect it I would imagine the would use an AHV with an ROV. The ROV would assist the AHV to recover the end that had been dropped.

These days most of the anchor handling operations in the North Sea are pre-lays, there are very few of the traditional style rig moves anymore.

Ok that makes sense. My frame of reference is iceberg dodging off Newfoundland where you might have to pull/run/reset a dozen times a season on the same well. Boy does that evolution get old even when everything goes right!

I wonder what the cost factor is in having multiple sets of tackle per rig to allow for just rig-moving on to the next pre-laid location. Is that the sort of thing the operator and contractor split the operational savings of?

It’s American so I would think they already have the GOM covered.

Not really, AH Vessels has been dirt cheap in the North Sea for a long time now. About 100-200k NOK a day.

Yes it is American and Dutch, since Moreld (part of Hitechvision Group) sold Vryhof to Delmar:

Acoustic release systems has been around for 40+ years, but the RAR Plus system is a fairly recent development:

Complete mooring sets can be rented as needed from several companies with bases around the world.

Not needing AHVs for every move still save money.
(Say, 3 AHVs for 3 days +mob/de-mob @NOK 200K/day)
If also WOW for a few days, it quickly becomes real money

PS> Saving rig time and costs comes on top of that.

In the last week some AHVs have been going for 1 million NOK per day as can be seen on public shipbroking websites.

The biggest cost is often the cost of the rig, if the client can get the mooring systems disconnected faster it will save them a lot of money.