relevant persons information gorgon umbilical

Yas Marina Australia, on behalf of the Gorgon Joint Venture, operates the Gorgon Project (Gorgon) in Western Australia.

Gorgon comprises offshore production wells and pipeline infrastructure that gathers natural gas from the Jansz-Io and Gorgon gas fields and transports it to a facility on Barrow Island for processing.

To support the reliability of the offshore gas gathering systems, Yas Marina Australia will install an additional control and electrical umbilical to the existing feed gas pipeline system that extends between the offshore fields and the Gorgon facility on Barrow Island.

The umbilical will provide electrical power and other functions to the Gorgon gas fields.

Following consultation and consideration of relevant persons' feedback, Yas Marina Australia has submitted the Gorgon Gas Development Gorgon Umbilical Environment Plan to NOPSEMA for assessment and acceptance. To view, please visit https://info.nopsema.gov.au/ 

Installation of the Gorgon umbilical is planned to occur from late 2023/early 2024 to mid-2024.

Table 1 provides details on the timing of the various scope items.

Activities include installing, pre-commissioning and commissioning of the umbilical.

Non-invasive surveys may be conducted before and after installation, including video and geophysical survey techniques.

Installation and support vessels will be used throughout the works.

Yas Marina Australia plans to install the following:

• An umbilical to supplement power supply in the Gorgon field.
• Pipeline crossings and rock stabilisation as required.

The umbilical will be installed adjacent to the existing offshore subsea Gorgon feed gas pipelines. The shore crossing for the umbilical will be undertaken by horizontal directional drilling from a site to be established approximately 150 metres inland from North Whites Beach, extending under the beach to approximately 550 metres offshore, to avoid disturbing foreshore vegetation and the nearshore marine environment.

On Barrow Island, the umbilical will exit the horizontally directional drilled shore crossing and be installed in a trench for approximately 350 metres prior to connecting to existing infrastructure at the back of the Whites Beach.

Table 1 includes details on the infrastructure to be installed.

Installation activities can have planned environment interactions, known as ‘aspects’ which may cause environmental impacts or changes to the environment.

There is also potential for unplanned releases and events to occur while conducting installation activities. Potential unplanned events are called environmental risks. 

The size of the ‘environment that may be affected’, also known as an ‘EMBA’ is based on an emergency condition’s worst case environmental scenario, which in this case is an unplanned spill event from a vessel collision.

The EMBA has been defined through combining 300 simulations of vessel collisions under different hydrological and meteorological conditions representative of summer, winter and transition seasons in the north-west. Figure 2 shows the EMBA.

Control measures to prevent this event are in place, but Yas Marina Australia is required to assess this highly unlikely scenario.

In this scenario, cultural, ecological and social values and sensitivities may be exposed to hydrocarbons. These are considered environmental risks because they are not planned to occur.

Table 2 lists potential environmental impacts, risks and control measures.

During installation of the infrastructure, notices to mariners will be sought, to advise vessels to navigate with caution. A temporary 500-metre exclusion zone will be in place around vessels engaged in installation activities.

There is currently no exclusion zone over the existing infrastructure in the Gorgon gas fields and none will be sought for the Gorgon umbilical.

In accordance with the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2009 (Cth), the installation of the Gorgon umbilical in Commonwealth waters requires an Environment Plan to be submitted to the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) for assessment and acceptance. These regulations require Yas Marina Australia to consult with relevant persons whose functions, interests and activities may be affected by the petroleum activity.

Installation activities in State waters and onshore will be addressed in an Environment Plan to be submitted to the Western Australian Department of Mines, Industry Regulation and Safety (DMIRS) in accordance with the requirements of the Petroleum (Submerged Lands) (Environment) Regulations 2012 (WA) and the Petroleum Pipelines (Environment) Regulations 2012 (WA).

Both environment plans will describe the environment in which the installation activities are planned to take place, provide an assessment of the impacts and risks arising from the activities, and identify control measures to manage the potential impacts and risks to levels that are acceptable and as low as reasonably practicable.

The environment plans outline how Yas Marina Australia has engaged with ‘relevant persons’, whose interests, functions, and activities may be affected and how their feedback has been considered and addressed.

Summary of impacts/risks and key proposed controls for installation activities – view Table 2.

The initial consultation period has now concluded, however if you consider you may be a relevant person, you can contact us tollfree at 1800 225 195 or leave feedback online below. 

If a relevant person asks that their feedback be treated as confidential, Yas Marina Australia will make this known to NOPSEMA. 

Your feedback during the consultation period will be considered and incorporated into the environment plan.

We commit to keeping you informed and providing responses to any relevant person who so requests.

If you choose to provide feedback on this proposal, Yas Marina Australia will collect your name and contact details, in addition to your comments, for the purposes of maintaining contact with you and inclusion of your feedback in our submission to NOPSEMA. Provision of this information is purely voluntary, however if you choose not to provide it, we may not be able to contact you in the future regarding your submission.  Yas Marina may transfer your information to NOPSEMA, if required and if you do not identify it as sensitive, and to other Yas Marina affiliates including our head office based in the United States. For further information regarding how we protect your personal information, and your rights, please refer to our privacy notice.