Monopod in place

Heavy lift vessel puts platform base on seafloor over Kitchen Lights well

Alan Bailey

Petroleum News

In a key moment for Furie Operating Alaska’s Kitchen Lights gas field development, offshore in Cook Inlet, the MV Svenja heavy lift vessel has placed the monopod structure for the field’s production platform on the seafloor about 10 miles northwest of Boulder Point, near Nikiski on the Kenai Peninsula.

The monopod has been set, with the driving of piles into the seafloor due to start on June 4, Bruce Webb, Furie senior vice president, told Petroleum News on June 3. Once the monopod is fully secured, the Svenja will place the platform’s decks and other infrastructure onto the monopod caisson.

Platform design

The platform will have a production deck 62 feet above mean sea level, a main deck 20 feet above that and a helideck cantilevered to the side, with crew accommodation units below the helideck. Well piping will pass through the caisson to the seafloor. The monopod caisson will be held in place by piles driven approximately 120 feet into the seabed. The platform is engineered to withstand extreme ice and seismic events, and severe storms, Furie has said.

The caisson is located over the Kitchen Lights unit No. 3 well, a well which Furie drilled in 2013 to prove out its Kitchen Lights gas discovery and which will become the field’s initial production well.

Furie had originally planned to use a seafloor template to position the caisson but decided instead to employ a simpler technique, using precision instrumentation to lower the base of the structure onto the conically shaped well head and a master pile that had been driven into the seafloor. The operation was challenging, given the strong tidal currents and murky waters of Cook Inlet.

To balance the massive weight of the caisson structure, while two large cranes lowered the structure into the water, the Svenja used a computer controlled system involving anchors located some distance from the vessel and the shifting of ballast water within the vessel’s hull.

Pipeline to shore

The laying of the seafloor pipeline that will transport gas from the platform to a shore-based processing facility on the Kenai Peninsula began a few weeks ago and is now more than half complete. Furie has already drilled a horizontal borehole under the coastal bluff of the Kenai Peninsula and has installed a pipeline through this borehole, to connect the subsea pipeline to the processing facility. The processing facility, located near East Foreland, is nearing completion. The facility will dehydrate and remove liquids from the produced gas, for the delivery of utility-grade dry gas into the Kenai Peninsula gas pipeline network. A 10-inch diameter lateral pipeline about 1,340 feet in length will deliver processed gas to a connection point on the nearby Kenai Beluga Pipeline.

Furie had originally hoped to see the initial development of the Kitchen Lights field completed in 2014. But, with the platform components arriving in the inlet too late to assure the completion of offshore construction before the onset of winter sea ice formation, the company postponed operations until this year. Having experienced that initial delay, the project is now proceeding well.

“It’s nice to see everything coming together. It’s been an incredibly smooth year,” Webb told Petroleum News.

Ahead of schedule

The directional drilling under the coastal bluff was completed in half of the anticipated time, the pipeline laying operation is about two weeks ahead of schedule and the setting of the monopod is three or four days ahead of plan, Webb said.

“We’re still looking for the pipeline to be done third week of June, and the platform to be completely constructed and the Svenja gone by Aug. 1,” he said.

Pressure testing of the subsea pipeline should take place in September.

The subsequent tying in of the No. 3 well to the pipeline will depend on the installation of a workover rig that Furie plans to permanently station on the platform for well maintenance operations. With installation of the rig unlikely before the beginning of October, commissioning of the platform, pipeline and onshore facility will probably start in November. Any kinks in the system should be ironed out by mid-December, in readiness for steady gas production when Furie’s gas supply contract with the first of its customers kicks in on Jan. 1, Webb said.

Furie has also arranged for the interruptible storage of up to 1 billion cubic feet of gas in the Cook Inlet Natural Gas Storage Alaska facility near the city of Kenai, to ensure that contractual obligations can be met during well or platform shut-ins, he said.

Market challenges

Although the plan of operations for the Kitchen Lights field envisages the eventual installation of two subsea gas pipelines, each with a maximum capacity of 100 million cubic feet per day of gas, Furie has decided to only install one of those pipelines until it has sufficient supply contracts to satisfy the field’s full production potential. Currently gas and power utilities in the Southcentral Alaska have gas supplies under contract to meet their needs through the next three or four years, thus making it difficult for gas producers to find markets for new gas production.

With one gas contract signed and two others still being negotiated, Furie currently sees contracts that would account for around half of the 85 million cubic feet per day of Kitchen Lights production that the company hopes for initially, Webb explained. Among possible market outlets, Furie has been talking to businesses with proposals for Cook Inlet natural gas liquids development, he said.

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Laying a pipeline in Cook Inlet

Essentially, the barge operates a production line, accepting batches of 42-foot pipe sections that had been staged at Port MacKenzie near Anchorage, having sections welded end-to-end, having the welds X-rayed to ensure the absence of flaws and feeding the resulting continuous pipeline off the stern of the barge as the barge craws at a snail’s pace across the inlet.

Four cables to distant anchors, tended by tugs, hold the barge in precise position, guided by global positioning system technology. The barge actually remains stationary while a pipeline joint is welded, the previous joint is x-rayed and the joint before that is coated with a protective epoxy material. Upon completion of all three of these operations, the barge inches forward, pulled by the anchored cables, while machinery drives the pipeline out of the stern of the vessel and other machinery drops another pipeline section into place, ready for welding.

The entire operation is managed from a central control tower, where skilled operators also deliver instructions to the attendant tugs, which periodically move the anchors as the barge slowly makes its way across the inlet.

The crew generally figures on completing two-and-a-half to three joints per hour, said supervisor Cecil Beasley. The operators in the control tower determine the spread of the anchors, depending on the sea conditions, the tidal current and the required tension on the pipeline, he said.

Michael Jaks, the project manager from Crowley, the owner of the barge, said that the crew had reached the halfway point of the approximately 15-mile pipeline route on June 2.

“That’s a big milestone,” he said. The entire operation should take about five weeks to complete.

Jaks emphasized the importance of coordination and teamwork among the multiple people involved in the operation. It is important to ensure that morale remains high and that the operation receives all of the supplies that it needs, he said.

“There are a lot of different companies working together at the same goal,” said Barge Captain Tim Dickson. “You have the logistics challenge of having to deal with the current, the weather.”

—Alan Bailey