Middle Ground Shoal

Cook Inlet Response

On February 7th Hilcorp Alaska identified a natural gas leak in Alaska’s Cook Inlet waters. The source is an 8 inch pipe located at a depth of 80 feet of water, and part Hilcorp’s Middle Ground Shoal (MGS) Fuel System. The system consists of approximately 15 miles of in-service natural gas pipeline and serves to fuel four existing production platforms.

Previous Updates

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.

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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.

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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.

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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.