A highly integrated team is meeting those challenges through innovative solutions and good project management.
Total, operator of Block 17 offshore Angola since 1993, with concessionaire Sonangol, made history with Girassol, the largest operation of its time offshore Angola. The French operating company is now executing an even more ambitious plan for the Dalia field, also in Block 17. This plan combines several innovative technologies to efficiently and cost-effectively produce the field whilst being in accordance with stringent company health, safety and environment (HSE) and sustainable development charters. The development will involve the investment by Total and partners of approximately US $3.6 billion, with first-oil expected in Q3, 2006.
Total's initial interest in the block was based on projections of geological trends from developments in neighboring blocks. The geology they actually found was not quite as expected, but the first exploration well discovered a much higher prospect - unconsolidated Oligocene sands that comprise the Girassol field, with an estimated billion barrels of light oil. Based on this success, a 3-D survey of target areas of Block 17 located a second major field with heavier (21˚ API) oil. Subsequently named Dalia, this is likely to become the largest operating field offshore Angola.
Dalia is the next in a series of oil fields named after flowers. It consists of unconsolidated, highly heterogeneous sands, but of even younger (Miocene) age, just 25 million years old. These turbidite sands accumulated at the mouth of the Congo River and have been affected by a succession of submarine slumps at the edge of the Angolan continental shelf. There are four identified major producing sand bodies, each several kilometers long and up to 260 ft (80 m) in the center, reducing to a few feet at the flanks. Approximately 2,600 ft (800 m) of thinly layered sands and clays lie between the reservoir and the seabed, with clay content progressively increasing upwards. The complex shapes of the sand bodies make connectivity an issue affecting producible reserves; however, according to Steve Yolland, Dalia partner relations manager, the "prognosis is staggeringly good so far - certainly more than Girassol." While Total is clearly the sole operator, Yolland is responsible for keeping the partners fully informed at all times of everything that is going on regarding the project.
Innovative solutions to deepwater challenges
Major challenges to the development of Dalia include 4,000-ft to 5,000-ft (1,200-m to 1,500-m) water depth and heavy, acidic oil at a low temperature of around 113˚F (45˚C). Located 84 miles (135 km) off the Angolan coast, there is no pipeline or other infrastructure to tap into. A 2,500 rig-day program has started to drill the 67 planned wells; 34 production, 30 water injection and three gas injection. A possible extension to 71 wells is already being considered to tap additional reserves. The surface and subsurface systems have been sized from the beginning for up to 100 wells, allowing for future satellite tie-backs and infill drilling, involving the management from the floating production, storage and offloading (FPSO) vessel of up to 17,000 underwater control points.
All of the production wells planned to date are single and near-horizontal, with an average 3,280-ft (1,000-m) drain. Intelligent completions will be installed in the seven wells that penetrate multiple producing layers. Schlumberger is providing these and all of the other completions. Each well has a dedicated drill-through horizontal Christmas tree. Flow from the 34 production wells will be routed to one of nine manifolds, featuring large- and small-bore piping and valves to permit production, hydraulic control and chemical injection. Each manifold is capable of connecting up to six wells, providing flexibility for up to 20 additional production wells in the future. This subsea production system (SPS) is under the responsibility of Work Package Manager Marc Perrot. It includes 4,000 tonnes of equipment being engineered, qualified, tested and manufactured by Kværner Oilfield Products. The process of assembling the network of seabed equipment by remotely operated vehicle (ROV) has been thoroughly tested in underwater conditions. Total has also prepared a computer animation to depict the subsea installations; however, as Steve Yolland notes, "with an area of approximately 40 sq miles (100 sq km), the footprint of the subsea installation is the size of a city, and it has proved a challenge for us to visualize the scale of the project."
The oil is transported to the FPSO through subsea pipelines comprising four 12-in. pipe-in-pipe (PIP) production loops connected to eight flexible risers incorporating innovative integrated production bundle (IPB) technology. There are also four water injection lines and two gas injection lines, each with a dedicated flexible riser. Nine umbilicals, for remote control of the Christmas trees and manifolds via hydraulic fluid and electrical signals, complete the subsea infrastructure. Five umbilicals are dedicated to the production loops and the northern gas injection well, with the other four controlling the water injection system and southern gas injectors.
The FPSO has a 2 million-bbl storage capacity and a processing system with a design capacity of 240,000 b/d. An innovative design, whereby the first stage is carried out under pressure, was selected for oil, water and gas separation of this relatively heavy oil while managing the risk of naphthenate deposition in the process vessels and piping. Produced water will be re-injected into the reservoir. Gas will either be re-injected or used as fuel, with the balance exported later to Angola LNG. The FPSO also includes the living quarters to accommodate up to 190 people as well as the main control room, which monitors the entire vessel's systems, including marine, process, metering and utilities. Oil offloading operations will be from a buoy, moored around 1.2 miles (2 km) from the FPSO for safety reasons. This will occur on average every 5 days during plateau production, aided by two tugs to ensure safe approach, berthing, offloading and departure. The unique combination of technologies deployed in Dalia will make it the first project in the world to produce oil at such a high production rate at such great water depth.
A truly integrated project team
A lesson reinforced by Total's experience of previous large-scale projects is the importance of a dedicated, experienced and integrated project team. Daniel Picard was appointed project manager in 2001, 2 years before the project was sanctioned. "We have a very experienced project team," Picard said. "We try hard to avoid turnover of key staff involved on the project. I want the same blokes to work on this until oil flows." For example, Michel Gloaguen, the umbilicals and flowlines (UFL) work package manager, was involved from day one of the design competition, as was Perrot, the subsea production system (SPS) work package manager. Actually, the project managers are not all "blokes;" several women are involved at very high levels. Anne Courbot, the field operations manager, has a very demanding job that includes training, commissioning, start-up, operations, service contracts and spare parts procurement for Dalia. Geneviève Mouillerat, FPSO work package manager, is meeting the challenge not only of the massive size and complexity of the FPSO, but also of working in South Korea, where women in top business positions are the exception.
"Another strong point is that we have built a highly integrated team," Picard said. Most project managers would probably make this claim, but in the case of Dalia it is supported by tangible evidence. The team is comprised of all involved parties, including geophysicists, geologists, reservoir engineers, drillers, UFL, SPS, FPSO and key future field operations staff. "This is why I need a strong deputy such as Jacques Thébault to help me manage the organization" Picard said. Total relocated all members of the team to the same floor of the same building in Pau, France. "Being close together means that when G&G (geophysicists and geologists) came up with an idea for new wells, the rest of the team could very quickly get updated and plan to accommodate the consequences," Picard said. "This has been key to our very efficient network of subsea facilities. Similarly, as G&G continually upwardly revised their expected production plateau, FPSO design was immediately made compatible." Picard said he believes integration is also good for the motivation of team members, while taking up no more of their time. "In some projects, groups pass their technical recommendations down the line and only discover much later, if at all, if and how they have been implemented," he says. "In our team, people very soon know the consequences of their decisions. The objective, which we have achieved, is that no one on the team will ever be surprised with 'breaking news' that might require them to lose valuable time abandoning or making major revisions to their plans."
A further benefit of the integrated team and thorough project planning is that Total has been able to make very cost-effective use of the two rigs - Pride Africa and Pride Angola. These rigs, equipped with dynamic positioning systems, were especially built for Block 17 exploration and development and have been modified specifically to manage the Dalia drilling campaign. "We are able to make best use of these rigs because we are very sure about our drilling program and confident about the geology that we will encounter, Picard said. "In a less integrated project, we would typically have made an initial 2-year agreement, then renegotiated the contract. Recent increases in the demand and price of rigs mean that we are likely to have incurred increased cost or delays that way." Each subsea Christmas tree is of the horizontal drill-through design, which considering the large number of wells will also substantially reduce drilling rig time. Picard is also pleased that Total placed the order for the FPSO when it did. "Recent increases in demand for ship building have created fierce competition for shipyard resources," he said. "It would have cost a lot more today." This boom in shipping has been accompanied by a world shortage of steel, due largely to increased demand from China.
As the project moves towards completion, team members are gradually relocating from Pau to Korea and Angola. The G&G and drilling groups are already in Luanda. Weekly team meetings are now carried out by telephone conference between Oslo, Paris, Luanda, Korea and Pau. When asked why they do not use videoconference, Picard responded, "After living together for 2 years, we know each other so well that we do not need to see each other's faces to understand who is talking and why.
"Compared to other projects that I have experienced, I think that we are much more integrated and in control" Picard added. "This does not, however, mean that we interfere; we give our individual project managers and contractors a lot of autonomy - so long as they are achieving!" Picard also praises his "back room" project services team. "They provide the heartbeat of the project," he said. Managed by David Walton, they take on the unglamorous work, such as contracts, invoicing, document control and reporting. The project is on track. Three years after the plans were first drawn-up, the topsides were installed on the FPSO hull within 2 days of schedule. "The project is now about 75% complete," Picard said. "Rather than look at project progress, we are now increasingly looking at run-down modules; tracking the completion of the last few tasks. We have some time left to complete the project, but we must be sure to keep doing it properly. All of the technical issues are under control including, and most importantly, all the new design features. We cannot be complacent, but I am confident that we will achieve our targets."
Reliable insulation key to flow management
The combination of technology being deployed for Dalia is specifically designed to handle heavy, cold oil, which makes flow assurance a key requirement. To prevent hydrate formation and maintain flow during normal production, the oil, at just 113˚F (45˚C) in situ, must arrive at the FPSO at more than 86˚F (30˚C), despite the seabed being at only 40˚F (4˚C). In addition, the temperature must not go below 70˚F (21˚C) in the event of shut-down before the line is preserved. Heat conservation and remedial heating systems are therefore essential. All in-sea equipment that carries produced reservoir fluid is thoroughly insulated. All insulated items, such as Christmas trees and manifolds, have undergone considerable qualification testing prior to deployment to confirm that there are absolutely no cold spots. Pipe-in-pipe (PIP) technology has been selected for the 22 miles (35 km) of production lines resting on the ocean floor. Insulation material, developed by Aspen Aerogels for the space industry, has been used for the first time on an industrial scale to fill the void between the inner and outer pipe. Integrated production bundle risers (IPBs), under the responsibility of Frédéric Roche, a member of Michel Gloaguen's UFL team, will carry the fluid to the ocean's surface. The IPBs, designed and fabricated by Technip, France, are flexible, so that they can yield to the random movements of sea currents. The IPBs are also equipped with 10 layers of insulation, plus 24 artificial gas lift tubes and six trace heating cables (used to avoid hydrate formation during shutdown) wound around the flexible pipe core. Flow lines and risers are 12 in. in diameter, considered optimum for maximum production whilst controlling the multiphase flow. Subsea manifolds include a pigging loop, enabling 12-in. pigs to be run from and back to the FPSO throughout the IPB and flow line network. The longest tieback is about 20,000 ft (6,000 m), a 7.5-mile (12-km) loop. Each 5,250-ft (1,600-m) IPB weighs 800 tonnes, and there are eight of them. Total has set a target of 100% reliability for all of the equipment being deployed in these deep, dark waters, as if it were being used in space. The IPB design has undergone an intensive qualification program. This involved 7 months of material qualification tests, followed by a mechanical test phase, including the "crushing test," "bending-pulling test" and perhaps the most spectacular of all: the Deepwater Immersion Performance (DIP) test, to validate the integrity of the design in deepwater conditions. The DIP tests were carried out in 4,900-ft (1,500-m) water depth offshore Brazil to assess the buckling behavior of the tensile armor. A sample pipe section was submitted to cyclic curvature variation comparable to the expected FPSO motion and also subjected to external pressure. Special calipers were slid down the sample after each cyclic test to detect any diameter variations due to buckling. The IPB was then dissected, analyzed and validated. Vertical full-scale thermal tests were also performed to confirm the thermal characteristics and performance over a 3-month period, by measuring the heat exchange coefficient, heating performance and cool-down times.
Building the FPSO
The 980-ft by 200-ft (300-m by 60-m) FPSO, weighing over 85,000 tonnes and with a surface area of more than four soccer pitches, is designed and built by Dalia Mar Profundo, a consortium of TSS (a joint venture between Technip, Stolt and Saipem), Samsung Heavy Industries (SHI) and Daewoo Shipbuilding & Marine Engineering (DSME). Construction of the hull started in January 2004 at the SHI shipyard in South Korea and it was launched on August 31, 2004, within 2 days of the scheduled date. The hull has since been towed across the bay to the DSME shipyard, where 30,000 tonnes of topside modules, constructed by both SHI and DSME, have been installed and are currently undergoing integration and commissioning. The topside equipment has a total area of about 65,000 sq ft (19,825 sq m) that will be covered by yellow paint. It includes three 24 MW generators, sufficient to power a small city. The FPSO is scheduled to sail to Angola in Q1 2006, a journey of more than 10,500 nautical miles (approximately 20,000 km), expected to last 90 days.
Comparison with Girassol
Dalia shares many of the features of Total's nearby Girassol field. Both are unconsolidated sand reservoirs, requiring extensive use of sand screens. Both are in deep water and in a remote location, requiring an FPSO. But there are some significant differences. "Girassol is complex, but Dalia is even more so," Picard said. "We have learned a lot from Girassol about operating in deep water, but we have not constrained ourselves to consider only technology that has worked for us before." A key contrast is that Dalia will produce cold, heavy oil, which makes flow assurance a key requirement. Dalia also has twice the number of wells, and the FPSO topsides are 25% bigger, due in part to the complications of processing heavy oil. Total figured that an FPSO would be required in any case, and the price for the IPB solution, following a design competition, was much better than for a riser tower of equivalent capacity. Another difference to Girassol is the use of horizontal drill-through Christmas trees. The different in-sea equipment also requires a different set of tools, including the ROVs. In any case, all the Girassol equipment and tools are fully deployed, so new ones would have to be bought.
Managing the HSE challenge
Scores of factory sites, located in Africa, Europe, Asia and the United States, are taking part in the development of Dalia, mobilizing up to 4,600 workers at any one time. Total estimates that by the time the installation produces its first oil in Q3 2006, the Dalia project will have used 15 million working hours. For Total, the search for constant improvement of HSE performance is the top priority for the project management. "Before we started the project," Picard said, "we rounded up all of our contractors in Paris for 2 days to have the importance of HSE drummed into them and to set the ground rules for reporting." A system has been implemented, including continual assessment and tools such as incentive schemes, to achieve the very stringent HSE requirements. Each manufacturing yard has an HSE Supervisor with authority to intervene in all aspects of operations. The HSE system in Korea includes monitoring of the weather and a comprehensive damage prevention and staff safety plan in the event of a typhoon. The seven-level, 2,500-tonne living quarters and control center on the FPSO is designed to be the ultimate refuge, gas-tight and able to resist hydrocarbon fires or even explosions. The module includes four totally enclosed motor-propelled survival craft for use in case of an evacuation. Examples of respect for the environment in the Dalia project plan include the elimination of gas flaring in normal operating conditions and the re-injection of produced water into the reservoirs, strategies that confirm Total's commitment to its emission reduction pledge.
A record-breaking project?
Dalia may not have broken any individual largest, deepest or other such oilfield development records, but the combination and complexity of Dalia makes it quite exceptional. Subsea developments are typically 20 to 40 wells, so with at least 67 wells, Dalia is big. There are some other IPB solutions around the world but never before at this scale. Picard is confident that Total has made the right decision in its choice of technology and that the project will be a success. "Everyone is pulling together to take the project forward," he said. "It is a really exciting project, and so far there have been no major difficulties, or in any case none that we have not solved. There's still a long way to go, but all hands are on deck and putting in a lot of work." It is not only the Dalia project teams that are working hard. Picard also praises the Total E&P Angola subsidiary and the advice coming from partners. Picard also recognizes the importance of Sonangol, whose input has paved the way to optimum solutions with respect to several technical and local infrastructure aspects of the project. With current world demand for oil, Dalia should provide a fair return on the $3.6 billion investment and deliver the Angolan nation and people the revenues and sustainable development that they deserve from these natural resources. Production from Block 17 is expected to peak in late 2006 through early 2007.