Gene Kliewer - Houston
Deepwater subsea production starts at India, GoM
One of the world’s largest deepwater production installations now is flowing natural gas from the Dhirubhai 1 and 3 discoveries in block KG-D6 off the east coast of India in the Bay of Bengal’s Krishna Godavari basin. At its peak, KG-D6 is expected to produce over 550,000 boe/d.
The facilities comprise wells and subsea architecture connected by flowlines and production risers to a control and riser platform, and tied back to the onshore terminal 60 km (37 mi) from the gas fields. That distance makes it one of the longest tiebacks in the world. At the seabed, equipment equivalent to more than 110,000 metric tons (121,254 tons) of steel and over 2,400 km (1,491 mi) of flowlines and umbilicals have been installed.
Subsea installation was by ROVs at ranging from 600 m to 1,200 m (1,968 ft to 3,937 ft). At the peak of offshore construction, the largest marine construction spread in the world comprising of 89 vessels was deployed over 400 sq km (154 sq mi).
Aker Solutions provided the production system including umbilicals under a $400-million contract covering 18 wells.
Oil and gas production has begun from the BHP Billiton-operated Shenzi development in the Gulf of Mexico Green Canyon block 653. The production platform has a nominal capacity of 100,000 b/d of oil and 50 MMcf/d of gas. Initial production is from seven wells connected to the platform. Production is expected to expand to 15 producing wells.
BHP further has awarded Stress Subsea Inc. a water injection design engineering contract for Shenzi field. The contract covers subsea hardware, umbilicals, risers, and flowline systems (SURF). Stress’ responsibility includes engineering and project management leading up to the execution phase. Stress also will be provide engineering services to BHP on subsea trees, controls, flowlines, sleds, and water injection risers.
Vega, Troll structures on the move
Three Vega subsea structures and the Troll O2 subsea structure are being completed, tested and made ready for delivery to the two StatoilHydro North Sea developments by Grenland Group’s Tønsberg yard.
The Vega subsea gas/condensate production equipment is scheduled for tie in to Gjøa which is scheduled to come onstream next year. The Troll O2 system is to be tied in with the Troll C platform.
Grenland also has a NOK38 million ($5.75 million) contract with FMC Technologies to construct the Troll B gas injection subsea structures for StatoilHydro. The contract covers two integrated satellite structures and two flow modules. Delivery is scheduled for 1Q 2010.
First-ever diverless flex riser scan recorded
Hess Ltd., working with flexible pipe specialist flexlife and AGR Field Operations, has completed the first-ever successful in situ scanning of flexible risers. Hess commissioned the inspection on theTriton FPSO, which produces oil and gas from the Bittern and Guillemot West Area fields in the North Sea. The work involved using flexlife’s patented ultrasonic scanning technology delivered by AGR Field Operations’ Neptune device, carried by Film-ocean’s inspection class ROV.
Left, a flooded riser and right, an unflooded riser
The technology can detect if there is a breached outer sheath and flooded annulus on a flexible riser or flowline. High-resolution images were obtained by scanning through the riser outer sheath showing the armor wires underneath. The ROV was deployed from the FPSO and testing was carried out in water depths of 20-30 m (66-98 ft) and currents approaching 1 knot.
The results were recorded using AGR’s proprietary Technology Design software and delivered in real time.
Aramco plans four platforms, subsea pipeline
Saudi Aramco has awarded a contract to J. Ray McDermott for the manufacture and installation of four platforms and a 110-km (68 mi) long subsea pipeline at Karan gas field. The pipeline will feed an onshore gas plant scheduled for startup in mid 2011. Aramco says Karan will produce 1.5 bcf/d of sour Khuff gas.
The project comprises four wellhead complexes each with a platform topside with gas, chemical injection, and controls facilities as well as a bridge connected auxiliary platform, associated flare bridges, and stacks. The four wellhead complexes are clustered around a tie-in platform with similar facilities. The project also includes intrafield pipelines as well as the trunkline to the shore and all subsea power distribution cables.
Cascade-Chinook moving ahead
The Cascade-Chinook development in the ultra deepwater Gulf of Mexico is moving ahead on schedule, says Cesar Palagi, Walker Ridge asset manager for Petrobras America.
The FPSO for Phase 1 is under construction in Singapore and is expected to arrive in the Gulf early next year, for first production in June, Palagi says. Heerema’sBalder is scheduled to start laying the pipe-in-pipe on the field.
Petrobras has taken a phase-approach to developing Cascade-Chinook. The first phase calls for tieback of three subsea wells to the FPSO. The primary objective of this phase is to gather well data to study reservoir behavior. This data will be used to design subsequent phases of the development, pending the well results in Phase 1, Palagi says.
Oil processed in Phase 1 will be offloaded to tankers and the small amount of associated gas produced will be piped to shore via the existing pipeline network.
