22 September 2013

Jake The Peg

Let's talk about jack-up rigs.
A jack-up rig can be described as a mobile oil-drilling platform fashioned as a ship or barge, towed by tug boats to the drilling site or oilfield. It is attached to jacks, like long legs. Once in location, the legs are jacked down to make contact with the sea-bed for fixing, while the platform itself is jacked up to a sufficient height to be away from  the elements of tide and current. There are several jack-up rigs in Kerteh's operational area, such as Rowan Gorilla, Enscoe 106, 105, West Leda and so forth.
The three-legged Jack. Jake with the extra leg!!
This week I got to visit West Leda twice. Initially it was when the rig was near the Telok A platform, a mere 60 miles off at about 047 radial from Kerteh. I had the opportunity then to make the approach to West Leda as the platform was oriented such that the south-westerly wind placed the obstructions towards the left, making it the left-hand seat pilot's approach.
I marveled as I usually do, at man's engineering prowess, that we should craft such beasts as these to stand in the sea and draw forth the sap of the earth for our power hungry needs. As I looked toward the left noting the obstructions and jack legs, it didn't quite strike me how clean those legs looked. I had always taken what I had seen for granted.
And then yesterday it was my second trip to West Leda. First thing in the morning, I had to determine the correct location of the platform, as it was on the move. From the platform's radio room, the weather report provided the GPS lat-long as aside Damar A, nearer the Lawit rig, on a the 354 radial and 129 miles up from Kerteh. I was quite pleased as it meant this would be a tad long-haul, though on the EC225 long-haul meant just over 2 hours of flying on one complete sector.
West Leda and the tug-boats
The Captain and I were chatting amiably about cycling, the Harley Sportster 883 and the recent heli Reunion, when it was ten minutes before landing at West Leda. I called the rig to get the weather, pertinent for the wind direction which would determine who would do the approach. After writing the details down, the static-laden voice over the radio said that there was movement of the platform as it was still on tow by the two tugs, and that pitch and roll were insignificant at less than 0.5 degrees both ways. I then requested confirmation that the towing would stop by landing time. The radio operator assured me in the affirmative, as another aircraft would be arriving before us for passenger drop off anyway.

Tug boat left
Slowly but surely, the three jacks and the platform emerged from the obscuring haze as we descended to a thousand feet off sea level. I noted the two tug boats pointing south-west, and concurred with the Captain that on our approach from the north-east to face the south-westerly wind, the boats would not be on the flight path, thereby not posing a hazard in case of a single-engine failure before being committed to landing on the deck. The Captain nodded, but I also perceived his satisfaction that with the helicopter deck canted to the south-east, this would be his approach.
Tug boat right
Upon landing, he elected to get down and do the headcount and jacket return count, so that he could also make use of the relief facilities. I updated the computers with the payload weight, selected our return home altitude on the automated modes and transferred fuel from the right tanks to the left for balance, while waiting for the passengers to disembark and new ones to get on board. I peered towards the right, and I noted that the jack-legs were covered with barnacles sure to rip the hide off an elephant. I had not hitherto noticed that profusion of barnacles on a jack-up rig before.
Blistering barnacles!!!
 I realised that I was such an offshore tourist.  When a jack-up platform is in site, the legs are jacked down. The levels at which barnacles attach to the legs would be way underwater, making whatever is visible to us all squeaky and handsome. Now that the platform was on a break for passenger exchange from towing mode, what is usually underwater was jacked up so that it didn't constitute drag, and to allow the platform to be buoyant for the tug-boats.
Interesting things we see in this business. 

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