Floating Production, Storage and Offloading (FPSO)
Floating production, storage, and offloading systems receive crude oil from deepwater wells and store it in their hull tanks until the crude can be pumped into shuttle tankers or oceangoing barges for transport to shore. Use of the FPSO's has the potential to improve industry's capabilities of developing oil and gas reserves on the Gulf of Mexico Outer Continental Shelf (OCS) in waters so deep that they either challenge or exceed existing deepwater production techniques and transportation systems. Deepwater is defined as water deeper than 200 meters.
In addition to FPSO's, there have been a number of ship-shaped Floating Storage and Offloading (FSO) systems (vessels with no production processing equipment) used in these same areas to support oil and gas developments. As of 2004 there was one FSO operated by PEMEX in the southern Gulf of Mexico (Bay of Campeche). A Floating Storage and Offloading (FSO) unit can be considered to be a subset of FPSO's. The FSO system lacks the oil and gas production processing capabilities of the FPSO. An FSO is typically used as a storage unit for production processed from other platforms that are remote from infrastructure and lack an oil pipeline to transport the oil to the refinery. One example is the Ta'Kuntah FSO that has been operating in the southern GOM (Mexican waters) since 1999. FPSO-like operations, including on-site storage of large volumes of produced oil, offloading operations, surface transport of OCS-produced crude oil, and the potential fate and effects of very large oil spills.
FPSOs generally are an amalgam of marine and petroleum functions, and therefore, present many specialized challenges for those involved in their creation. Their turret structures are designed to anchor the vessel, allow "weather vaning" of the units to accommodate environmental conditions, permit the constant flow of oil and production fluids from vessel to undersea field, all while being a structure capable of quick disconnect in the event of emergency.
An FPSO system is an offshore production facility that is typically ship-shaped and stores crude oil in tanks located in the hull of the vessel. The crude oil is periodically offloaded to shuttle tankers or ocean-going barges for transport to shore. FPSO's may be used as production facilities to develop marginal oil fields or fields in deepwater areas remote from the existing OCS pipeline infrastructure. FPSO's have been used to develop offshore fields around the world since the late 1970's. They have been used predominately in the North Sea, Brazil, Southeast Asian/South China Seas, the Mediterranean Sea, Australia, and off the West Coast of Africa. As of 2004 there were 70 FPSO's in operation or under construction worldwide.
Several organizations have developed comprehensive databases for all offshore incidents. A study by INTEC Engineering was commissioned by DeepStar early in the environmental impact statement (EIS) process to identify the spill history for FPSO operations. DeepStar is a multiphase deepwater technology study currently funded by 16 oil companies and more than 40 contributing manufacturers, vendors, consulting organizations, classification organizations, and contractors. The largest spill from an FPSO occurred in the late 1990's - approximately 3,900 barrels of oil were spilled from the Texaco Captain FPSO during startup at its field location. The spill was attributed to human error during the start-up procedure; an overboard dump valve was inadvertently left open and hydrocarbons were released. Oil spills from all other FPSO operations have reportedly spilled less than 500 barrels of oil combined. FPSO's have been successfully operating for a cumulative 460 plus FPSO-years, processing an estimated 6.4 billion barrels of crude oil.
The MMS and DeepStar developed the FPSO scenario to be representative of the range of typical FPSO's that would be likely to operate in the GOM during the next 10 years. Expertise representing FPSO operating companies, designers and builders, equipment manufacturers, classification society organizations, and government agencies were involved in the system definition used for the FPSO base case. The base case scenario studied in the EIS was a generic FPSO system that can be described as follows: permanently moored, fully weathervaning turret; double-hulled (sides and bottom per OPA 90), ship-shaped; storage up to 1 million barrels of crude oil; 300,000 barrels of oil and 300 million cubic feet of gas per day processing capability; multiple subsea wells producing back to the FPSO; conventional, ship-shaped, shuttle tankers with 500,000 barrel storage capabilities. The base case investigated in the EIS addressed shuttle tankers.
The use of a conventional shuttle tanker was identified by the industry/MMS/USCG team as the most likely scenario for an FPSO-based development in the GOM. The EIS does not exclude the use of ATB's; both shuttle tankers and ATB's would transport the oil from the FPSO to shore. The EIS addressed the potential use of ATB's as part of the range of technical options for the proposed action. In responding to comments on the draft EIS, the USCG stated that they consider an ATB to be a specialized type of integrated tug barge (ITB) and subject to policies described in the USCG Navigation and Vessel Inspection Circular (NVIC) 2-81 (Change 1). The use of ATB's is an issue that the USCG would address in their permit requirements for the FPSO-based development.
Concurrent with the EIS, the MMS-funded Comparative Risk Analysis (CRA) was performed to compare the relative risks of an FPSO system with three other deepwater development systems: fixed platform production hub, a spar, and a tension leg platform (TLP). All of the production systems except the FPSO are currently in use for deepwater development projects in the U.S. Gulf of Mexico. The study was performed under contract to the Offshore Technology Research Center, with technical support from EQE International and the industry consortium DeepStar. The CRA used the same base-case FPSO system that was used in the EIS. The overall intent of the CRA was to provide MMS context and perspective for FPSO risks, and to assist with MMS decisions regarding the potential use of FPSO's in the Gulf OCS. The CRA was also designed to help MMS understand the risk contributions of the various components (subsystems) and phases of operation. The CRA concluded that there are no significant differences in the oil-spill risks among the four systems studied (FPSO, TLP, Spar, and Fixed Jacket Platform serving as a Production Hub/Host). The MMS and the study participants deemed it not necessary, for purposes of the CRA study, to mitigate the FPSObased development to a lower level than the risk levels represented by the existing deepwater production systems. The CRA did include a limited effort to identify potential risk reducing measures but these were not quantitatively investigated.
The Griffin oil and gas project is located 62 kilometres offshore on the North West Shelf in Western Australian waters. Oil and gas from the Griffin, Chinook and Scindian fields are produced via the Griffin Venture, a floating production, storage and offloading facility (FPSO). The Griffin Venture is a disconnectable vessel, able to relocate in the event of a cyclone, with gas processing facilities on board. The processing facilities on board separate the produced oil, water and gas. Crude oil is offloaded from the Griffin Venture to shuttle tankers via a floating hose; the oil is then delivered to markets. Griffin gas is piped to shore and exported directly into the Dampier-to-Bunbury Natural Gas Pipeline. Natural gas is sold into the Western Australian market under long-term contracts.
Jackson Lane Pty Ltd was engaged by BHP Petroleum to provide preliminary design layouts and advice for both new-build and tanker conversion options for crew accommodation aboard a new floating production facility. A tanker [ex-Solfonn, ex-Juan A.Lavalleja, ex-Lympia, etc] was ultimately purchased by BHP Petroleum for FPSO conversion. The vessel was 273.00 m LOA, with 69,359 GRT, 49933 NRT and 131664 DWT. Conversion included crew accommodation re-fit, asbestos removal, design of a helideck for Bell 214 ST helicopters, and free-fall life boat arrangements.
The MODEC Venture 1 FPSO is a converted tanker with a disconnectable external turret. The MODEC Venture 1, installed in 1998 has been successfully operating in the Elang/Kakatua/Kakatua North oil fields in the Timor Gap JPDA (Joint Petroleum Development Area) and continues oil production from the wells. The base FPSO of MODEC Venture 1 (ex-Skua Venture) was previously owned by BHP Petroleum led joint venture and located on the BHPP operated Skua field in the Timor Sea. MODEC purchased the FPSO ex-Skua Venture and upgraded the vessel to meet the new field requirements. MODEC leases the FPSO and manages all the operations for the Elang/Kakatua/Kakatua North fields.
Keppel Shipyard, the marine unit of Keppel Corporation, has set a new benchmark for fast-track conversions of highly complex Floating Production Storage Offloading facilities (FPSO) with the delivery of FPSO Brazil to Single Buoy Moorings (SBM) Inc. The Ex. Esso Saba / Esso Freeport / ex Moscliff was converted to FPSO Brazil. "Esso Saba" was built in 1974, and became "Esso Freeport" in 1984. She had a draft of 20.09 meters and LOA 348.72 meters. The 256,712 dwt vessel, FPSO Brazil, was leased to Petrobras SA for deployment in the Roncador Field in the Campos Basin off the coast of Brazil. It is capable of handling up to 100,000 bpd of crude oil production and a storage capacity of approximately 1.7 million barrels.
The Roncador Field was discovered in 1996 at water depths ranging from 1,500 to 2,000 m (4,900 to 6,600 ft) in the Campos Basin. It is 125 km (80 miles) from the coast. The Roncador Field was a major breakthrough for many reasons, including the world's first drill pipe riser, subsea tree and early production riser (EPR) rated for 2,000 m (6,600 ft). The first well, RJS-436, produced to the FPSO Seillean from 1999 to 2001 using the EPR at a world water-depth record of 1,853 m (6,077 ft) with the GLL TLD 2000 subsea tree. The first phase of this full-scale project was put onstream in May 2000 when the semi and FSO P-47 began operation. An accident caused P-36 to sink in March 2001, when six (6) wells were in production. After the accident, Petrobras chartered a production unit called FPSO Brazil to temporarily substitute the P-36 platform. For a period of 5-1/2 years, eight (8) production and three (3) injection wells will be connected to the chartered FPSO.
The world's largest FPSO is the Kizomba A, it has a storage capacity of 2.2 million barrels. Built at a cost of over US$800 million by Hyundai Heavy Industries in Ulsan, Korea, it is operated by Esso Exploration Angola (ExxonMobil). Located in 1200 meters (4,000 ft) of water at Deepwater block 150 statute miles (320 km) offshore in the Atlantic Ocean from Angola, West Africa, it displaces 81,000 tons and is 285 meters long, 63 meters beam, and 32 meters high ((935 ft by 207 ft by 105 ft).
Contracted through Hyundai Heavy Industries, FMC SOFEC was responsible for the design and analysis of the Kizomba B FPSO mooring system. The supply of the off-vessel equipment (wire, chain, piles) as well as the installation of the system was once again the responsibility of the EPC3 installation contractor. The SOFEC« mooring system is DnV classed.
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