The development of the Nini East Field off the coast of Denmark by Dong Energy involves the construction of a new, unmanned production platform and a 7km subsea pipeline to the existing Nini platform. A compact new design of subsea valve gearbox from Rotork Gears has provided a timely and successful solution to the challenging problem on a North Sea pipeline project. As part of the contract for the project, a UK valvemaker is supplying a Class 1500, 6in metal seated double block and bleed ball valve for a critical duty demanding zero seat leakage on liquid and gas duty. Due to the specific constraints if the valve installation, the valvemaker’s engineers were advised that access for ROV operation could only be possible from above the valve and no access from the sides could be permitted. In addition, there were restrictions to the allowable overall dimensions of the valve and gearbox package due to the surrounding fabrication. Working closely with the valvemaker, Rotork Gears proposed a new gearbox design that met the size restrictions without compromising the technical performance. The new gearbox design, known as the DS range, proved to be the most compact solution available whilst manufacture of the two units required was achieved on a lead time that complied with the project requirements. When installed, the high pressure valve package will be operating at a depth of 58m. The Nini East Field development is expected to extend the life of the Nini Field for at least another 10 years.
