This project marks the first multi-million pound contract the SME has completed. As MD Richard Hay states, "The West Azeri project has been fantastic for DEC. We used our hydraulics and first hand experience to design a simple to operate, easily maintained and highly effective package that really fitted the bill. With the West Azeri project now complete, we have started the East Azeri, and are working hard to meet the delivery date of March 2004".
The venture allowed the parent company (DGC) to grow significantly, and they now have a cylinder manufacturing division as well as service and electronic/electrical design and build divisions in the UK. The company has also recently expanded into the US with the opening of DEC Inc in Houston. The firm additionally plans to open an office in Baku to maintain local support for the then operational Skid System, as well as acting as a Regional Business Development office.
DEC has worked closely with drilling contractor KCA Deutag, and has been able to design, manufacture, assemble, test and certify a complete package of grippers, skidding cylinders, BOP lift cylinders and trolleys, clamps, levelling plates and control consoles all within a very short time frame.
The equipment is truly gargantuan in size – twice as large as any system currently operating in the North Sea.
Due to the tight operational window, the unit was designed to enable maximum drill time and is even capable of operation at full setback. A key element in the design was maintenance access. All 10 cylinders on each gripper are able to be individually isolated and removed from the top, without dismantling the gripper assembly. These gripper cylinders are also common to the 36 levelling cylinders which has the additional benefit of minimizing spare parts holding.
Running on two weather deck common rails, the skid operation travels North/South and East/West. The Rig Skidding Grippers consist of a group of 10 single acting hydraulic cylinders assembled into a plate which lies on top of the skid rails and generates 2000 Te of grip. This is attached to 2 side frames which hook under the flange of the skid rail. Clamping is achieved by energizing the cylinders which then clamps the side frames to the flange. Skidding is achieved by twin cylinders with 650 Te Pull, mounted either side of the gripper assembly. One complete assembly is located on each of the 4 skid rails.
Eight off hydraulically operated clamp system located at four positions under the DES on top of the Skid Base and at four positions under the Skid Base on the skid rails, locks the DES in place until it is required to be moved from one well slot to another. Each of the 2 cylinders per set gives a clamp force of 560 tonne. The load is transferred to the side of the flange of the skid rails by a clamp plate which spreads the load over an area much greater than the diameter of the cylinder rod.
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