Shallow-water project includes several innovations
Peter Howard Wertheim, Dayse Abrantes, Special Correspondents
Devon Energy’s Polvo field in the Campos basin is progressing at a rate which could make it the quickest such project from discovery to first production in Brazil’s oil and gas history. The current schedule calls for three years from discovery, in June 2004, to first oil, scheduled for July 2007, says Steven Seat, development manager for BM-C-8.
At year-end 2005, Devon held an interst in four deepwater blocks and one shallow water block offshore Brazil. In total, Devon held more than 800,000 net acres off Brazil at the time.
The fasttrack development schedule resulted from Devon and Korea’s SK beginning platform fabrication work early in order to take advantage of an installation window using equipment in country for another project.
The concept is simple but innovative for use in shallow-water oil fields off Brazil. The principal difference between Polvo and other shallow-water operations in Brazil is use of higher capacity drilling equipment. The drilling equipment, with 3,000 hp, is movable and can drill up to 6 km vertical with 1 km horizontal.
Devon purchased the equipment in the Gulf of Mexico with the plan to install it on the field’s jacket for a 13-well drilling campaign - 10 for production plus three for water injection.
This schematic, courtesy Devon Energy, illustrates how the partners plan to complete development at Polvo.
Devon installed the rig on the jacket because it expects to find additional reservoirs in the block.
The jacket design is simple and compact. On its topside, three multi-stage pumps will be installed to move the fluids, without separation, directly to an FPSO. Historically, FPSOs have been used only in deepwater off Brazil.
The FPSO, contracted with Norway’s Prosafe, will have a 1.5 MMbbl storage capacity. The unit is also equipped with production capacity for 90,000 b/d of oil 100,000 b/d for water injection. The FPSO will be installed in 105 m of water.
“We have entered the third phase of the exploratory program for the BM-C-8 block, which includes drilling three vertical wells by September 2007. In 2007, we will also start drilling the 13 development wells for the Polvo field,” says Seat.
The 50,000 b/d oil field development plan includes a fixed drilling and production platform that will be connected to an FPSO. The platform jacket and deck are being built by US-based Kiewit Offshore Services. They will be installed in late 2006 by Heerema using theThialf. Empresa Brasileira de Solda Elétrica S/A in Rio de Janeiro state will supply the piles.
The FPSO will be leased from owner/operator Prosafe Production Services on a $271 million leasing contract.
Devon owns 60% of the exploration block, which was acquired at the second National Petroleum Agency bidding round in 2000. SK Corp. owns the remaining 40% working interest. Polvo reserves are estimated at 50 MMbbl of 19° API gravity crude. Local press reports say the company plans to spend $200-$300 million to develop Polvo.
Devon has some other contracts for Polvo block BM C-8 in the works in addition to the Prosafe letter of intent for the turret-moored FPSO.
Devon issued tenders for a 24-slot platform for installation 1.5 km from the FPSO. Bidders include Brazilian and Korean firms. Devon chose Kiewit Offshore Services’ yard in Corpus Christi, Texas, to build the deck and jacket. Piles will be built at Brazil’s Maua-Jurong shipyard. At print, the 38-man living quarters module contract was still outstanding.
Rio de Janeiro’s energy secretariat informed Devon prior to invitation to tender, that all work done outside of Brazil would have a 19% tax added to enter the country. After 36 months in Brazilian waters, the FPSO also would have a tax affixed to it. Validity of the laws supporting the application of such taxes is being debated in court.
Devon is monitoring prices for the platform parts in order to meet the 40% local content commitment.
Excel completes engineering for Devon at Polvo
Preliminary engineering, and detailed design and engineering for the Devon-operated Polvo development at block BM-C-8 has been completed by Excel Engineering.
The platform design calls for a drilling rig, 24 well slots, production equipment, and all utility systems. The jacket and deck are being fabricated and are scheduled for installation later in 2006, with start-up in mid-2007.
The production facility is designed for 100,000 b/d of liquids and 5 MMcf/d of gas. The high viscosity crude will be pumped from the wells by electric submersible pumps with variable-speed drives. A multi-phase meter was specified rather than a test separator to minimize deck space requirements.
The multi-phase pumps will send production to an FPSO for processing and storage.
A process control and safety system based on an Allen-Bradley ControlLogix PLC will be used. One major function of the PCSS is to monitor submersible pump performance. The PCSS uses a distributed input/output philosophy to minimize installation while maximizing communication of data among all the facilities, including the drilling rig and FPSO.
An existing platform is being refurbished for the project. Excel performed the engineering support for the rig modifications, including the design of a new skid base with integral tanks to support the rig structure. Two cranes are being added to the rig pump and mud modules for drilling operations.
Many of the drilling rig systems are being integrated with the production facility systems, including the drilling rig bulk fluids unloading system.
Excel provided engineering assistance with development of performance specifications for the FPSO. The FPSO will support the production, separation, water treatment, power generation and production storage for the field.
Two pipelines will connect the platform and the FPSO. Excel sized these lines to carry production to the FPSO and injection water from the FPSO to the platform;
