Meeting your obligations for decommissioning

Article published in the Regulator | Issue 2: 2019 

When offshore petroleum infrastructure will no longer be used to support petroleum operations a titleholder must remove or otherwise satisfactorily deal with the disused infrastructure. This process is called decommissioning. While there are a number of decision makers involved in the regulation of decommissioning, it is NOPSEMA’s role is to assess the relevant risk management plans for the activity to ensure they meet all safety, well integrity and environmental management requirements.

Typically, decommissioning occurs at the end of petroleum operations but must also be undertaken for any disused infrastructure throughout the life of an offshore petroleum project. NOPSEMA considers the complete removal of infrastructure and the plugging and abandoning of wells as the base case scenario for all offshore decommissioning activities. A titleholder may propose decommissioning options other than the complete removal of infrastructure but the proposed option must deliver equal or better well integrity and environmental outcomes.

NOPSEMA will challenge any arguments made by titleholders that attempt to inaccurately represent the feasibility or practicability of complete removal of infrastructure. For example, when assessing decommissioning options, titleholders should be considering the use of decommissioning campaigns, the availability of nearby rigs and vessels, emerging technology and the collaborative use of decommissioning resources.

Titleholders will often use comparative assessments in their environment plans to assess different options for decommissioning. While options to partly remove, re-use or leave infrastructure in the marine environment may be proposed, titleholders must remember to include the base case scenario for complete removal throughout their evaluation and assessment process. When a decommissioning option is finally selected, NOPSEMA may require the titleholder to provide a range of scientific studies and environmental data to support that selection. For example, a titleholder may choose to identify, measure and assess the value of offshore infrastructure to fish assemblages in a particular geographical location to support their case for leaving infrastructure in the marine environment.

If a titleholder proposes to leave infrastructure in the marine environment, their environment plan must then demonstrate the acceptability of any long term impacts and risks of leaving that infrastructure. In this instance, if a comparative assessment is used, then it is important for titleholders to involve stakeholders early in the development stages of the comparative assessment. This will help to ensure that different viewpoints are captured and stakeholder expectations are understood and considered before any decision on is made on a preferred decommissioning option. NOPSEMA is encouraged to note that industry has commenced discussions aimed at increasing consistency in the approaches that may be taken to evaluate and demonstrate appropriate decommissioning outcomes. NOPSEMA, in conjunction with the Department of Industry, Innovation and Science, will continue engagement with the industry and other stakeholders to ensure that any approach addresses the relevant legislative requirements.

The National Offshore Petroleum Titles Administrator and the Joint Authority will request advice from NOPSEMA prior to making title-related decisions where titles, or parts of titles, are to revert to vacant acreage. NOPSEMA provides advice on matters such as if all property has been removed or alternative arrangements have been made, if wells have been plugged and abandoned, if the conservation and protection of natural resources in the titles is provided for, and if any damage to the seabed or subsoil has been made good.