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BP in Alaska: Initial Prudhoe field development
Frank Baker For Petroleum News
In the late 1960s and early 1970s development drilling was under way at Prudhoe Bay, using Nabors 18-E and Brinkerhoff Rig 36. Everett Potter, now retired, was a drilling consultant for BP. Potter says modern rigs are better insulated and heated than the old ones, and much more transportable.
“We used to have to tear the rigs down to the ground to move them by truck from one well location to another,” he remembers. “A rig move could take as long as seven days, especially during the winter months. Now, some of the rigs can be moved in half a day, and wheel-mounted rigs can simply be rolled to other locations.” Modern cantilevered rigs can be moved from one well location on a pad to another location in just a matter of hours.
Brian Rose, a retired drilling superintendent for BP, joined the company in 1974 and became drilling foreman on Brinkerhoff Rig 36 and Nabors 18-E.
“I got off the plane at Deadhorse and it was about minus 20 degrees with a 30-mile-per-hour wind. A guy named Swede Swenson, a drilling foreman, picked me up at the airport in a yellow station wagon. I remember thinking to myself, ‘What have you gone and done now?’”
The first sealift to Prudhoe Bay occurred in the summer of 1969, when about 70,000 tons of stores and equipment were barged from Seattle. The 1970 barge sealift was the largest in the North Slope’s history — when 70 barges containing more than 175,000 tons of equipment journeyed north through difficult ice conditions.
From 1974 on, sealift shipments to Prudhoe Bay would contain oil production modules, buildings, modularized camps and other support facilities from the U.S. West Coast. The barge shipments were made by Seattle-based Crowley Maritime Inc.
The sealifts also brought large modules for BP’s three gathering centers, which would separate gas and water from produced oil. ARCO would have three similar facilities, called flow stations, on its side of the field. Under a unit operating agreement, BP would operate the western side of the Prudhoe Bay field, or western operating area (WOA), and ARCO would operate the eastern side, or EOA.
The plan called for the six facilities to handle up to 1.8 million barrels of oil per day. By 1975 two of BP’s gathering centers were in place — each capable of handling about 300,000 barrels of oil per day.
During this time, a gravel “spine” road was built from east to west through the heart of the oil field, using gravel from approved material sites. Later, extensions and fingers off this road would access the many gravel “pads” from which development wells would be drilled. Pads were assigned letters on the western or BP-Sohio side of the oil field and numbers on the eastern, or ARCO side.
While initial facilities were being installed, expansions to those facilities were already being designed by BP in San Francisco. During the mid-1970s, when major capital expansions reached a crescendo on both sides of the Prudhoe Bay field, the areawide population peaked at about 8,000.
Extreme climate fosters innovation As Prudhoe Bay Field was being planned in the early 1970s, challenges of an extreme climate moved BP toward two other innovations. Both were motivated by the company’s caution in working in a new environment.
The major concern was whether people could really work effectively outdoors during the frigid Arctic winter, according to Brian Davies, a former BP Alaska vice president, now retired, who had been involved with the North Slope since the early 1970s. This led the company toward a concept of building large processing modules, and even living quarters, in warmer climates and moving them by barge to the North Slope.
Davies says BP was the first to build and move large modules to a remote site. It was a concept borrowed from offshore oil platforms, which are built in modules and towed on barges to the final location. But building very large modules weighing thousands of tons and moving them thousands of miles by barge and then several miles inland was a first. What made it possible was technology borrowed from the space industry, the specialized tracked vehicles that could move very heavy weights like rockets for several miles, Davies says.
ARCO Alaska, BP’s co-operator at Prudhoe, chose at first to build its flow stations by traditional methods, where structures were largely fabricated on site, but later followed BP’s lead in modularized construction.
ARCO’s later start in modularized construction was to have benefits, however. Being able to learn from BP’s experience, ARCO was able to incorporate improvements, particularly in the size of the facilities, which was of benefit to BP in its own expansions of production facilities.
Centralized control BP’s centralized field control system, developed in the mid-1970s, was a revolutionary concept for the industry at the time. It allowed controllers in one location in the field to manage hundreds of individual wells as well as many functions in the field crude-oil gathering centers by telemetry and microwave transmission. This took less time than sending people out to the production sites. It was also safer when weather was bad.
“At first BP’s plan was to have even the field Gathering Centers unmanned, operated remotely from the Main Operations Center (MOC),” recalls Dave Catchpole, a BP process engineer who along with fellow BP engineer Tom Adzima, developed Prudhoe’s Supervisory Control and Data Acquisition (SCADA) system in the early 1970s.
Automation gave BP significant operational advantages: It provided the ability to quickly adjust production rates of wells on the western side of the Prudhoe Bay Field in as little as two or three minutes, and to shut the entire western side of the field down in less than 30 minutes.
BP’s ability to react faster in controlling its well flow if the trans-Alaska oil pipeline had to temporarily slow its crude oil throughput made it the “swing producer” for Prudhoe. Through automation, BP could react faster in slowing or shutting-in production than ARCO, which at first relied on more traditional oilfield control systems, with people posted at the drill sites. ARCO later automated its system and developed several innovations of its own.
BP’s first camp BP’s first camp in 1969, Mukluk Camp, consisted of a few trailer units. The company’s permanent base camp was shipped in modular form from Seattle to Prudhoe Bay in mid-1973 on eight barges. The following year the first phase of the Central Power Station (CPS) arrived, which consisted of two turbine generators and a control room. The Prudhoe Unit agreed to locate it on the western side of the field — making it a BP-Sohio-run facility.
According to Jim Barrett, then a supervisor at the station, the facility generated about two megawatts during its first year of operation. Later sea-lift shipments would bring the other three phases, which included five more Frame-5 turbine generators which were fueled by natural gas produced in the Prudhoe Bay field. Today, the CPS has a maximum output capacity of 160 megawatts, making it the second-largest single power station in Alaska. The CPS provides all electrical power for Prudhoe Unit oil production operations, and current plans call for its expansion. Diesel generators throughout the field provide a backup to provide life support, such as heating and emergency lights.
In 1976 the three-story BP-Sohio center, sometimes called the BP Hilton, was expanded from 90,000 to 137,400 square feet, providing living and working room to accommodate about 264 people. BP also built two 500-person camps for contractors developing the field.
Bill Lorenz, a BP North Slope construction veteran of about 25 years, now retired, notes that when Prudhoe facilities were first being installed, he couldn’t foresee what they would eventually look like, or how big they would become. “Most of the production modules and buildings were designed by BP and Ralph M. Parsons Inc. of Pasadena, Calif., and came from the U.S. West Coast as increments,” he remembers. “They were like jigsaw pieces of a bigger whole that we never saw until it was completed.”
“The initial gathering centers were almost ‘pass-through’ facilities compared to today’s multi faceted complexes, and about one-third the size,” recalls Fritz Wiese, who spent many years on the North Slope as BP production manager.
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