Taking the new requirement on board was relatively straightforward - since the rig is in a modular form, a new package has been added in the shape of a 350-ton drilling support module (DSM), according to Steve Balne of Hitec Drilling.
Hitec is the main contractor for the design, construction, commissioning and delivery of the P&A rig, which is being built by Ilitec and Dreco in Edmonton, Canada. It is due to start work in spring or early summer 1998.
The upgrade will give the rig the capability to drill to a depth of 20,000 ft. Facilities in the DSM include mud pits, mud pumps, power generation facilities and two equipment rooms, and are contained in eight modules on a skiddable base frame. The new module is due for delivery this autumn.
Equipment in the DSM will be remotely controlled from the drillers' control cabin in the drilling equipment set (DES), which also interfaces with the rig support module (RSM).
The P&A rig is a unique concept for the North Sea, being specifically designed to be moved around between different platforms. For this reason, it is in a modular form, weighing in total 1,000 tons. The various modules can be added on or taken off, according to the desired function.
The rig will be used by drilling contractor Smedvig, which is to plug more than 100 wells on 10 of Phillips' platforms in the Ekofisk complex, as part of an extensive platform decommissioning operation.
However, one of the key design criteria was that the dismantled rig should be capable of being lifted on and off platforms using only the platform cranes - a tough requirement as this limits lifts to 20 tons. As some of the units weigh more than 20 tons, a lot of additional design work was entailed to minimize the dismantling operation, Balne says.
The rig is a self-sufficient unit which will operate independently of the host platform's facilities, which may well be shut down by the time the rig arrives. It has its own emergency shutdown, fire and gas, and telecommunications systems, which can be tied into the host platform's facilties if these are functioning.
The mast is of a self-erecting type using the rig drawworks or a scoping winch. For drilling purposes a top drive machine will be used, while the plugging operations will be performed by kelly.
Hitec's Cyberbase control system is used for the remote control of all essential functions, including horizontal and vertical pipe-handling, drillfloor operations, mud treatment, electrical systems, instrument systemsand HVAC.
Recently, Hitec also bought back the Hitec-Dreco drilling rig it supplied to Norske Shell's Draugen platform. It plans to refurbish and sell the rig, which was used to drill only five wells.
Copyright 1998 Oil & Gas Journal. All Rights Reserved.