Terra Nova Development: Challenges and Lessons Learned

Abstract

Abstract In the past 10 years developments in technology and the opening up of new frontiers, combined with a demand to move into greater water depths have resulted in considerable increase in the use of floating facilities for offshore oil production. The Terra Nova Development has and will establish a number of project "firsts" including the first FPSO to operate in North American waters and the first to operate in a harsh North Atlantic environment frequented by sea ice and icebergs. Also stereotypical of this region are cold air and water temperatures, seasonal fog, and heavy seas. Overcoming these challenges has required Terra Nova to adopt the lessons learned from pervious FPSO developments in the North Sea, while using both proven and new technology, and utilizing the benefits on an alliance-based contracting approach. The result is a unique development solution with a number of lessons learned. Introduction The Terra Nova oilfield is located approximately 350km (220 miles) east-southeast of St. John's, Newfoundland, 35km (22 miles) southeast of the Hibernia oilfield in a water depth of 90 to 100m (295-330ft.). Figure 1 shows the field location. The total recoverable oil reserves in the field are estimated by the Canada-Newfoundland Offshore Petroleum Board (CNOPB) to be some 64?106m3 (400 million barrels). The top of the reservoir is located 3,200m (10,500ft.) below the seafloor. The field is made up of three geological fault blocks: the Graben, the East Flank and Far East as shown in Figure 2. Only the Graben and East Flank blocks have been delineated. Twenty-four wells are proposed for Graben and East Flank: 14 producers, 7 water injection and 3 gas injectors. If further delineation drilling in the Far East block, which is planned for 2002, locates commercially viable hydrocarbon reserves, an additional 5 producers and 5 water injectors may be required. The Terra Nova field development concept is shown in Figure 3. An ice strengthened, double-hulled Floating Production, Storage and Offloading (FPSO) facility with subsea wells and gathering system will be used for the development of the Terra Nova field. Development wells are being drilled using the mobile semisubmersible drilling unit "Henry Goodrich," through seven subsea templates placed in four 10m deep glory holes, used to protect the wellheads and xmas trees from scouring icebergs. Trenched and rock bermed flowlines connected to flexible risers will link the subsea wells to the FPSO. Crude will be offloaded by a dynamically-positioned shuttle tanker positioned at the stern of the FPSO. Terra Nova - A Project of Firsts The Terra Nova Development has set a large number of "firsts" which have significantly contributed to the challenges in the execution of the project. These "firsts" are varied in theme and include:First FPSO development on the Grand Banks and only the second offshore oil development on the challenging Grand Banks of Newfoundland.First offshore facility in Canada to be certified to both offshore petroleum and shipping regulations.First fully-automated quick disconnectable turret and riser system on a FPSO.