Nabors International unveiled its new modular Rig 702, the first of two headed for Papua New Guinea (PNG) for a 900-day contract with options for ExxonMobil. The rig, constructed at HongHua America’s yard in south Houston, is designed for PNG’s intense rainforest climate.
“Rainfall there totals 10 meters per year,” said Nabors senior vice president-engineering Padira Reddy. The mud tanks are enclosed, and, to prevent rain-water contamination, the Minimum Area AC rig (MAAC) is designed to catch all contaminated run-off.
ExxonMobil and Nabors signed the contract in April 2010, and rig construction began that June. The initial contract term is 900 days for 14 wells, Mr Reddy said. Nabors is also building a sister rig, 703, for PNG, also at HongHua.
The system’s modularity will facilitate its transport into PNG’s rainforest, Mr Reddy explained. The box-on-box substructure features a 44-ft floor height with 38-ft clearance below.
To enhance safety, Nabors rotated the rig floor 90° to relocate the catwalk away from the wellhead. This also provides better access to the wellhead and BOP stack, the company said. The wide-open substructure design aims to facilitate moves over existing wellheads and simultaneous production and workover operations on adjacent wells during either drilling or rig moving. A 200-ton dual-direction BOP hoist system allows continuous access to the BOPs from either end of the substructure. The BOP hoist can bring the complete BOP stack fully outside the substructure for safe handling.
The mud system is designed to handle 22-lb/gal mud and comprises three Continental Emsco FC-1600 pumps rated to 1,600 hp and 7,500 psi, with mud-pump synchronization. The fully enclosed, cylindrical mud pits feature hemispheric, cornerless bottoms. This eliminates all dead spaces during agitation and uniform fluid suspension. Each tank is equipped with a GamaJet self-cleaning tank system, eliminating confined-space work by personnel.
Rigs 702 and 703 are equipped for managed pressure drilling, Nabors says, and can maintain constant bottomhole pressure via continuous mud circulation while making connections.
Rig 702 features numerous automated features, including a Canrig PC-4000 automated power catwalk, Canrig TM-120 automated floor wrench and a PHANTOM rotating mousehole, manufactured by Access Oil Tools.
The rig also employs Canrig’s RigWatch, a rig-monitoring system able to consolidate and provide in real time third-party information, including MWD, LWD, mudlogging and wireline.