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BP in Alaska: Offshore challenges — Endicott, Northstar, Liberty
Frank Baker For Petroleum News
Following Prudhoe and Kuparuk, Endicott was the third major oil field developed on the North Slope by BP, the field’s major interest owner. The Sag Delta discovery, 10 miles northeast of Prudhoe Bay and two miles offshore, was made by BP in 1978. Development, however, didn’t begin until 1985, when more than 6 million cubic yards of gravel was trucked from shore to create a five-mile-long causeway and two islands.
Endicott represented the third generation of North Slope oil field facilities, benefiting from lessons learned in the construction of Prudhoe Bay and Kuparuk.
One of Endicott’s main features was its compactness: The entire production facility, along with initial drilling site, worker housing, utilities, warehouse and other facilities, would fit onto a 45-acre island. A causeway would connect this island, called the Main Production Island, to shore and to a smaller island, called the Satellite Drilling Island.
To prevent erosion from wave action due to summer storms, the perimeters of the islands were lined with large concrete blocks and bags. Large breaches or bridges were built into the causeway to allow fish movement. Wells were drilled 10 feet apart — closer together than in any previous Slope development. This helped significantly reduce the amount of space needed for field development.
The production modules were built in Louisiana and barged to Endicott in 1986 and 1987. Although some of the facilities were the largest ever brought to the Slope — fitting through the Panama Canal with only inches to spare — they were built for economy and purpose.
Unlike some Prudhoe Bay installations, which include multiple backup systems, Endicott’s facilities were kept simple.
In addition to ARCO and Exxon, partners with BP at Endicott included three Native corporations: Cook Inlet Region Inc., Doyon Ltd. and NANA. Doyon was also one of the field’s main drilling contractors for several years.
Completed a year ahead of schedule and about $600 million under budget, the Endicott field began producing in October 1987 and has produced more than half of its 600 million barrels of recoverable oil. Field development costs were slightly more than $1 billion. Endicott production began in October 1987 and in the early 1990s achieved a peak rate of 120,000 barrels per day. It is currently producing about 15,000 barrels per day.
Endicott was one of the first North Slope fields to achieve Voluntary Protection Program status through the U.S. Occupational, Health and Safety Administration. VPP is a merit program based on exemplary safety performance that allows operators greater autonomy and self-regulation in administering health and safety programs.
Endicott preparing for future Beginning in 2008, the Endicott field embarked upon a five-year renewal plan that will ensure operations integrity and prepare the field for increased oil production rates for decades to come.
Twenty-one years after its startup, Endicott has yielded more than 500 million barrels of oil equivalent, and is still producing about 15,000 barrels of oil per day. But with current development plans, which include processing oil from the nearby Liberty field, Lo-Sal production, carbon dioxide injection and facility upgrades, the facilities’ daily oil production rate could more than triple and extend the field’s life to 2040.
Endicott Field Manager TJ Barnes says that major infrastructure upgrades — from wellhead to oil processing facilities — are at the heart of the five-year renewal plan.
Alaska Consolidated Team (ACT) Resource Manager John Denis says that a logical progression in Endicott’s development will be LoSalTM enhanced oil recovery (EOR) followed by CO2 recovery when major gas sales begins.
CO2 will need to be extracted from the gas used for sales to the Lower 48 and the CO2 can then be used as a solvent to extract more oil from existing reservoirs. CO2 EOR is a proven technology that will have broad applications across the North Slope.
“We’ve rebuilt our reservoir models and have developed a comprehensive depletion plan for Endicott,” notes Denis. “We’re into the fourth year of a program to stabilize and improve the reliability of our facilities and wellstock, we have brought OMS to Endicott, and we have a robust program under way to renew our facilities. With the development of new technologies like LoSal and production from the new Liberty field, we’re looking ahead to a very bright future for Endicott.”
At any one time there are between 70 and 90 workers at Endicott, which consists of two man-made, gravel islands connected to each other and to shore by a five-mile-long gravel causeway.
Beginning in 2007, Endicott was also among 16 BP-operated sites across the world to pilot the Operations Management System (OMS), the company’s global, overarching standard for safety and integrity management in construction and operations.
As part of an ongoing effort to make the site a safer and more efficient place to work, Endicott personnel have advanced several continuous improvement projects and adopted Control of Work tenets that exemplify OMS principles.
BP holds a 67.9 percent interest in Endicott. Other major owners are ExxonMobil, 21 percent and Chevron, 10.5 percent.
Northstar shines bright for today, tomorrow Nearly a decade after field startup, Northstar is producing about 34,000 barrels of oil per day, a significant contribution to BP Alaska’s North Slope net production.
As Northstar’s operator, BP Alaska has a 98.6 percent interest in the field.
The field is located offshore in the Beaufort Sea, about five and a half miles northwest of Prudhoe Bay in about 39 feet of water.
Northstar is the first Arctic offshore field connected to shore only by pipeline, delivering its oil via a six-mile, subsea line.
Construction of the Northstar field began in late 1999.
In the winter and spring of 2000, construction crews rebuilt Seal Island, an existing artificial gravel exploration island, into the permanent production island for Northstar. Production facilities were built in Alaska and barged to the North Slope.
The modules were the largest oil production facilities ever fabricated in Alaska, and required a peak workforce of 1,000.
Workers also installed a 17-mile pipeline connecting the island to the trans-Alaska oil pipeline.
A six-mile section of the 10-inch-diameter oil line was buried in the sea floor. Crews installed the offshore section of the line by cutting a slot in the sea ice.
Seal Island was built by Shell Western E&P in the early 1980s after it discovered the Northstar field. Shell and its partner Amerada Hess drilled five appraisal wells, but the field was never developed because development costs were too high.
BP Exploration (Alaska) Inc. acquired Shell’s and Amerada’s interests in the field in early 1995 and authorized construction in 1996 after Alaska Gov. Tony Knowles and the Alaska State Legislature agreed to change a high percentage net profits royalty into a 20 to 27.5 percent sliding scale royalty tied to oil price.
Despite construction delays caused by permitting delays and legal challenges, Northstar was back on track in 1999. The project workforce peaked in spring 2000 with more than 1,000 people employed on the project in Anchorage, Fairbanks and the North Slope. Northstar began production in October 2001.
With about 176 million barrels of recoverable reserves, Northstar is a small field when compared to the very large North Slope fields developed earlier.
Lots of ‘firsts’ at Northstar Northstar development involved a number of “firsts” for BP and the petroleum industry:
• It is the first Arctic offshore field connected only by pipeline to shore. (The larger Endicott field, which has been producing since 1987, is closer to shore and is connected by a gravel causeway.)
• The six-mile pipeline has a wall thickness triple those of typical onshore North Slope pipelines, and is state-of-the-art. The pipeline has three separate leak detection systems, including a system capable of detecting very small leaks (as little as one barrel per day).
• BP committed to the state that it would construct large sea-lift modules in Alaska and conduct training for Alaskans. Module units built in Anchorage were the largest ever constructed in the state.
Other special engineering and design features include pipe burial to nine feet below the seafloor — almost three times the ice gouge depth that would be caused by a 100-year event; high strength, pipe; and two types of corrosion protection: double thickness fusion bonded epoxy coating and aluminum anodes to provide cathodic protection.
With a 98.08 percent interest, BP Exploration (Alaska) is the Northstar operator. Murphy Oil holds a 1.92 percent interest.
Environmental issues Northstar is a state-of-the-art facility that produces and processes the field’s fluids from a five-acre production island, with a footprint of about .05 percent of the reservoir’s area.
Northstar is a zero-discharge facility. Waste is re-used, recycled, or taken ashore for proper disposal.
Numerous environmental studies have been undertaken in the area to determine potential impacts of Northstar island operations on marine mammals and fish. Air and water quality are also monitored on a regular basis.
Liberty: the extended reach One of the most exciting projects in BP Alaska’s business portfolio is Liberty, an offshore oil field located in the Beaufort Sea. With about 100 million barrels of recoverable oil, it is one of the largest undeveloped reservoirs of light oil on the North Slope. The entire field is located in federal waters.
BP will develop Liberty from existing infrastructure using world-class ultra extended-reach drilling technology. The Liberty field lies under federal waters of the outer continental shelf some 15 miles east of Prudhoe Bay and ranges from 7 to 10 miles east of BP’s existing Endicott development. The center of the reservoir is approximately 5.5 miles from the nearest land.
Historically, the only way to develop a field like this was to construct an artificial gravel island and a subsea pipeline to get production to shore, as was done at Northstar, a field BP developed in the late 1990s. Or, in the case of BP’s Endicott field, a causeway was built to connect the islands to shore.
However, with advances in drilling technology, like the ultra-extended-reach wells BP pioneered, it is now possible to develop fields like Liberty in a very different way.
BP’s plan is to drill wells from the easternmost drill pad at Endicott — the Satellite Drilling Island. The SDI will be enlarged to process Liberty fluids through the existing Endicott facilities. The SDI’s working surface will be expanded from about 11 to 31 acres.
Endicott has been a very successful development, but has seen oil production decline from peak rates of some 120,000 barrels per day to less than 20,000 at present. As a result, Liberty will be able to take advantage of Endicott’s underused facilities.
Using existing facilities tied into the North Slope road system enhances safety by providing year-round overland access and maximizes environmental protection by avoiding construction of new offshore or onshore drilling pads or pipelines.
Environmental concerns Through its decades of experience in the Arctic, BP recognizes the concerns of North Slope residents over the potential environmental impacts of offshore development. Before, during and after construction, and after the field begins producing, environmental monitoring will be conducted in the area. Studies will include assessments to determine whether fish, marine mammals (including whales), birds and other wildlife are impacted.
The Liberty project will generate significant revenues to the North Slope Borough and to the state and federal governments through taxes and royalties.
The total investment at Liberty is expected to exceed $1 billion, and at peak production in 2012-13, Liberty is expected to produce about 40,000 barrels of oil per day.
Production will be sent by the Endicott production flowlines from the SDI to the Endicott Main Production Island for processing. The oil will then be transported to the trans-Alaska oil pipeline via the Endicott sales oil pipeline. Produced gas will be used for fuel gas and artificial lift for Liberty, with the balance being re-injected into the Endicott reservoir for enhanced oil recovery. Water for waterflooding will be provided via the existing produced-water injection system at the SDI. This supply will be augmented by treated seawater if needed from the Endicott Seawater Treatment Plant.
Liberty moves ahead on several fronts By early 2009, BP Alaska’s Liberty project was in high gear, with drilling rig fabrication under way and North Slope activities focusing on Endicott Satellite Drilling Island (SDI) expansion, camp and facility fabrication and improvements to the Sagavanirktok (Sag) River bridge, which are nearing completion.
Parker Drilling Co. was constructing a special drilling rig for Liberty that will be capable of drilling the ultra-long, extended-reach wells. Major fabrication and outfitting of the rig was being completed in Vancouver, Wash., at Thompson Metal Fab Inc. Fabrication of the rig power module was under way at ASRC shops in Anchorage and on the Kenai Peninsula. It will be the largest land-based drilling rig ever built.
The rig was expected to be moved to the Endicott SDI in the summer of 2009 by barge during the ice-free period. Plans call for the rig to be fully commissioned and ready to begin drilling during the first quarter of 2010. The first ultra extended-reach well is expected to begin in the second quarter of 2010.
During the winter of 2008 and spring of 2009, Endicott’s Satellite Drilling Island was being expanded to accommodate the new drilling rig and the five to six wells that will be drilled. Facilities for the expanded island, which include a camp and production facilities, were being fabricated in Anchorage.
Another phase to the Liberty project involves improvements to the Sagavanirktok River bridge on the eastern side of the Prudhoe Bay field. The bridge has been in service for more than 30 years to support Endicott as well as many other North Slope operations and developments. To prepare the aging bridge for many more years of service and to support Liberty construction and drilling activities, the existing bridge pilings were to be reinforced and the main structure replaced.
The Liberty project will set standards for Arctic development while minimizing the onshore and offshore environmental footprints. Liberty will take advantage of existing infrastructure in Endicott field, which has been producing oil since 1987.
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