ANCHORAGE, Alaska - Divers have placed a clamp over a hole in an underwater Alaska pipeline, stopping the flow of millions of cubic feet of natural gas into Cook Inlet, home to endangered beluga whales.
Hilcorp Alaska, a subsidiary of Houston-based Hilcorp, announced Friday that divers Thursday night covered a gash at the bottom of the 8-inch diameter line in 80 feet of water. They measured the hole at less than 0.5 square inches.
"A total of 12 dives were completed on the fuel gas line in order to locate the leak, then properly position, stabilize and prepare the pipeline for repair," Hilcorp spokeswoman Lori Nelson said by email.
Cook Inlet covers 180 miles from the Gulf of Alaska to Anchorage. A Hilcorp helicopter crew spotted gas bubbling from the line Feb. 7 about 4 miles offshore.
The pipeline carries processed natural gas to four production platforms, where it's burned to generate electricity. Analysis of gas flow indicated the pipeline probably started leaking in mid-December and initially spewed up to 310,000 cubic feet of natural gas per day.
Hilcorp lowered pressure in the line to reduce the daily flow to 85,000 to 115,000 cubic feet.
The inlet is notorious for extreme tides that produce strong currents. Hilcorp held off on repairs until the additional threat to divers of floating ice had diminished.
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Divers for Hilcorp halt monthslong Cook Inlet gas leak
Author: Alex DeMarban
Updated: 6 hours ago
Hilcorp Alaska has stopped a natural gas leak in Cook Inlet that released methane for months and generated concerns about impacts to wildlife and calls for increased scrutiny of the Inlet's dated oil and gas facilities.
Dive crews on Thursday night "safely and successfully" installed a clamp on the marine pipeline, Hilcorp said in a prepared statement.
The repair required multiple dives to the seafloor over the past week. State officials have said the damaged line is 80 feet deep.
Hilcorp will continue inspecting the 52-year-old pipeline and take additional steps to stabilize and protect it, the company said.
The subsea leak was discovered Feb. 7 but Hilcorp data showed it had been occurring since late December, according to federal pipeline regulators. The leak was northwest of Nikiski, about 3 1/2 miles off the coast.
Thick sea ice presented dangers to dive crews, delaying repairs for two months.
Bob Shavelson, with watchdog group Cook Inletkeeper, said Hilcorp's inability to repair the pipeline in winter is worrisome.
"If it takes Hilcorp months and months to shut in a leaky line, we need to re-evaluate whether they can operate in the Alaska winter," he said.
Hilcorp’s Platform A on April 2. A pipeline that delivers natural gas used as fuel for this platform and three others began leaking in December. (Bill Roth / Alaska Dispatch News)
With warming weather melting the sea ice enough by Saturday, divers began efforts in the murky water to find the damaged spot.
"A total of 12 dives were completed on the fuel gas line in order to locate the leak, then properly position, stabilize and prepare the pipeline for repair," Hilcorp said in the statement issued by spokeswoman Lori Nelson.
Divers installed a steel and rubber clamp over the leak, creating a seal that won't release liquids or gas, the company said. The gash, found on the bottom of the pipeline atop a boulder embedded in the seafloor, was initially estimated to be about 2 inches wide.
But closer inspection, after the pipe was lifted more than 1 foot off the seafloor, and after divers removed mineral buildup on the outside of the pipe, showed a smaller gash, less than a half-inch long and across.
The pipeline was the first installed in Cook Inlet in 1965 as the oil and gas industry was launching a rapid construction program in the basin. By the end of the decade, 14 production platforms were built.
Originally, the pipeline delivered oil to a shore-based processing facility, tapping the Middle Ground Shoal field, the first offshore discovery in Alaska, with Shell the operator at the time.
As facilities changed hands over the decades, the line in 2005 was converted to natural gas. It delivered fuel gas 7 miles to operations at Platform A, and also to other nearby production platforms at the field. Hilcorp Alaska acquired it in 2015 from XTO Energy.
Unable to immediately make dive repairs, Hilcorp, with approval from regulators, decided against completely shutting down the line. The company said it was concerned that residual oil left in the line could leak into the environment.
But after discussions with Gov. Bill Walker, Hilcorp in late March shut down the small oil production from the field. That allowed Hilcorp to significantly reduce the amount of fuel gas flowing through the line, and reduce the leak.
The 8-inch pipeline was originally installed next to an oil pipeline that still delivers crude oil today and has generated concerns among regulators and watchdogs that it too will leak, subject to the same threats that led to the gas line leak.
Hilcorp Alaska said it is taking steps to further inspect and protect the oil line from damage.
"Neither pipeline will be returned to regular service until Hilcorp, along with state and federal regulators, agree it is safe to do so," the company said.
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Updates: 04-14-2017
ANCHORAGE, AK – April 14, 2017 –
Dive crews safely and successfully installed a clamp on the fuel gas
line in Middle Ground Shoal last night, stopping the release of natural
gas from the affected pipeline. Weather and ice conditions allowed
divers to begin their work on Saturday, April 8. A total of 12 dives
were completed on the fuel gas line in order to locate the leak, then
properly position, stabilize and prepare the pipeline for repair.
The leak point was located on the very bottom of the pipeline, resting
on a boulder embedded in the seafloor. Initial visual inspections noted
the breach to be approximately 2” in size. The affected section of the
line was lifted approximately 1.5’ from the seafloor, then stabilized,
allowing for closer, more careful inspection of the leak site.
Divers removed scaling and cleaned the exterior of the line. Exact
measurements of the breach were taken, recording the actual size at
3/16”W x 3/8”L. After proper cleaning and preparation, a steel and
rubber clamp was installed over the leak. The clamp assures a gas tight,
liquid tight seal that will reinforce the pipeline.
The repair operation was provided to the Alaska Department of
Environmental Conservation and the Pipeline and Hazardous Materials
Safety Administration.
Now that the leak has been stopped, over the next several days, as
weather permits, further inspection and stabilization of both the oil
and gas pipelines in Middle Ground Shoal will be completed. Neither
pipeline will be returned to regular service until Hilcorp, along with
state and federal regulators, agree it is safe to do so.
Updates: 04-10-2017
ANCHORAGE, AK – April 10, 2017 –
Hilcorp continues response efforts, in coordination with state and
federal regulatory authorities, to repair an 8-inch natural gas pipeline
in the Middle Ground Shoal area of the Cook Inlet.
Dive crews mobilized from Homer on Friday April 7th and have been
able to safely work through the weekend. Divers have identified the leak
location, and are working to prepare the site to
allow for the installation of a temporary clamp.
The leak point, approximately two inches in length, was noted to be
on the very bottom of the pipeline resting on a boulder embedded in the
seafloor.
Following completion of the initial repair, further inspection and
work will be done to permanently repair the affected segment of pipe.
The line will not be returned to service until permanent repairs have
been completed, the line has been pressure tested, and regulators have
approved a re-start.
We will provide further updates as new information becomes available.
###
Updates: 03-27-2017
Hilcorp safely completed
production shut-in procedures over the weekend in Middle Ground Shoal.
The gas pipeline is now operating at minimum pressure (65psi). The
reduced leak rate is estimated to be 85-115 thousand cubic feet per
day. Pumps are circulating filtered sea water through the adjacent oil
pipeline to reduce the risk of freezing in the line. Production will be
restored when Hilcorp, along with federal and state regulators,
confirm that it is safe to do so. Based on current weather forecasts
and ice conditions Hilcorp expects to mobilize equipment and deploy
divers to begin repair operations within the next 10 days.
Updates: 03-25-2017
ANCHORAGE, AK – March 25, 2017 –
Hilcorp continues response efforts, in coordination with state and
federal regulatory authorities, to repair an 8-inch natural gas pipeline
in the Middle Ground Shoal area of the Cook Inlet.
After recent discussions with Governor Walker and meetings with the
Alaska Department of Environmental Conservation, the parties have agreed
to reduce the pressure in the gas pipeline to approximately 65 psi.
This will necessitate shutting in oil production from Middle Ground
Shoal platforms A & C. Hilcorp appreciates the proactive and
transparent way Governor Walker has expressed his concerns regarding
this matter.
Previous weather conditions have prevented Hilcorp from shutting in
oil production at an earlier date. Shutting in wells and idling lines
and equipment in very cold temperatures create a known risk of freeze-up
and potential rupture. Warmer ambient temperatures now permit a safer
shut in process of the wells along with the associated lines and
equipment.
Shutting in oil production allows the gas pipeline to operate with 65
psi, the minimum positive pressure. Minimum positive pressure is
necessary to prevent water from entering the line and a potential
washout of the residual crude oil that remains in the pipeline.
Further, maintaining minimum pressure on the line will allow for the
platforms to run essential equipment and safety systems.
As Hilcorp works with state and federal agencies to finalize the plan
to reduce gas line pressure, shut-in production and repair the
pipeline, the safety of personnel, wildlife and the environment remain
the top priority.
Planning and preparations have already begun, and once approved by the regulators, shut-in procedures will begin this weekend.
Hilcorp’s response team and the necessary equipment are ready to
immediately commence repair operations as soon as it can be done safely.
Based on current weather forecasts Hilcorp anticipates repair
operations to occur in the next two weeks.
###
Updates: 03-24-2017
ANCHORAGE, AK – Hilcorp
continues response efforts, in coordination with state and federal
regulatory authorities, to repair an 8-inch natural gas pipeline in the
Middle Ground Shoal area of the Cook Inlet.
Weather and ice conditions allowed the sampling and monitoring
programs approved by the Alaska Department of Environmental Conservation
(ADEC) to begin on March 18th.
Water quality data was collected by floating a sampling buoy directly
downstream from the identified leak location. Initial laboratory
results from numerous samples taken in the area of the leak showed no
meaningful adverse impacts to water quality. The full sampling report
was provided to ADEC on March 22nd. Samples were consistent with
previous modeling and, to date, all water samples have measured notably
better than ADEC’s minimum Water Quality Standards for Coastal Marine
Waters. Hilcorp believes the samples also demonstrate that current water
quality does not pose a threat to wildlife. As an added precaution,
certified marine mammal and wildlife observers will continue to monitor
the leak site and surrounding areas.
Hilcorp will continue our monitoring program and we will be working
with ADEC to review the data we collect. Air and Water Interface
Sampling equipment is being calibrated and is expected to deploy today.
Ice conditions continue to delay our repair operations. However, the
weather forecasts have improved and based on these current forecasts
Hilcorp anticipates repair operations to occur in the next two weeks.
###
Updates: 03-17-2017
Hilcorp will work with PHMSA and
other state and federal agencies to ensure a thorough and timely
response to the concerns in the proposed order. Hilcorp continues to
focus on addressing the natural gas pipeline leak and ensuring the
safety of our responders in the field.
The “B” pipeline currently transports produced fluid to shore and is
operating normally. The steel pipeline is 8” in diameter and 8.6 miles
in length. Hilcorp acquired the pipeline in September 2015 at which time
the company completed a successful pressure test on the line.
Updates: 03-14-2017
Hilcorp has reduced the
operating pressure of the line to limit the volume of the natural gas
release and to maintain sufficient pressure to prevent water intrusion
into the line.
Ice conditions continue to delay repair operations at this time.
Hilcorp is conducting frequent ice observations utilizing National
Oceanic and Atmospheric Administration guidelines. Cook Inlet Regional
Citizens Advisory Council has also provided access to its ice camera
network to assist with that effort.
Hilcorp’s response team is ready and the necessary equipment has been
staged to commence repair operations as soon as conditions permit a
safe working environment for response personnel. Once conditions allow
for safe operations, Hilcorp will undertake repairs which will take
several days.
Hilcorp conducted baseline air and water sampling, and continues to
conduct direct observation of the affected area, and impact modeling of
the natural gas release. To date, no significant impacts to wildlife or
the environment have been observed and the release does not pose a
threat to the general public.
Today the Alaska Department of Environmental Conservation gave
preliminary approval to Hilcorp’s broader sampling and monitoring
program that was submitted last week. We will begin implementing the
monitoring program in several stages as conditions allow using marine
vessels, buoys and other equipment. Additional updates will be provided
as significant new information is available.
Updates: 03-08-2017
Based upon observations to date,
the release does not pose a threat to the public nor the environment,
however ensuring the safety of our response personnel is our top
priority as we proceed. We are pleased that PHMSA’s Proposed Safety
Order acknowledges this, recognizing that immediate repair is not a
viable option due to current conditions and concerns for the safety of
personnel. Hilcorp will continue to work with PHMSA and other state and
federal agencies to ensure a thorough and timely response. Hilcorp’s
focus right now is addressing the natural gas pipeline leak and ensuring
the safety of our responders in the field. An investigation into the
timing and cause of the leak is currently underway.
Updates: 02-15-2017
We will continue to monitor ice
conditions and will dispatch divers when it is safe to do so. The
safety of our people and the environment remains our priority as we work
with the proper authorities on how to best manage this situation. It is
important to note that this fuel gas line, which brings natural gas
from the shore to Platforms A and C, provides for the safe operation of
both platforms and shutting in the line would put the it at risk of
taking in water, freezing and potentially rupturing.
Updates: 02-15-2017
The natural gas currently
flowing through the line provides power to four offshore platforms:
Baker, Dillon, A & C. At present, ice conditions in Cook Inlet
continue to prevent divers from accessing the pipeline safely. The
safety of our personnel and the environment remain a top priority as we
work to respond to the leak. It is estimated the leak volume is
approximately 210 -310 thousand cubic feet of natural gas per day.
Hilcorp’s platform crews have shut down non-essential equipment. This
step has been taken in order to reduce natural gas flow to the minimum
operational gas pressure possible without jeopardizing employee safety
or the environment. However, maintaining positive pressure in the flow
line is necessary to ensure any residual hydrocarbons are not released
to the Inlet. If a minimum pressure is not maintained in the pipeline
it could fill with water which would allow for the escape of residual
crude oil, as this line was previously used as a crude oil pipeline.
Daily overflights above the line are being conducted. No sheen on the
water surface has been observed to date. Shutting in the pipeline
presents safety risks for our people, the environment, and has the
potential to further damage offshore infrastructure. We will continue to
monitor ice conditions and line pressure while working with the
appropriate agencies on our response.
