Case Study 15 Mar 2023

Produced Water Quality Monitoring – Australian offshore production assets

Woodside operates seven offshore production assets off the north-west coast of Western Australia. Produced water that is brought up from the reservoirs as a by product of oil or gas production is managed differently at each asset.

North Rankin Complex

Image: North Rankin Complex

This depends on a number of factors including reservoir characteristics, how much water is produced, potential toxicity and proximity to sensitive receptors. Of the seven assets, four currently discharge the produced water offshore following treatment, two reinject the water back into the formation and one sends the water onshore for processing. 

Potential impacts from produced water are managed in accordance with the Woodside Offshore Marine Discharges Adaptive Management Plan (OMDAMP). The OMDAMP allows for an adaptive approach that implements a range of monitoring and assessment tools, including such things as desk top analysis, chemical management, asset based monitoring and periodic field based environmental verification sampling.

The objectives of the OMDAMP are to:

  • Manage produced water discharges in a way that reduces environmental risks and potential impacts to as low as reasonably practical and of an acceptable level
  • Define monitoring measures to determine whether routine discharges meet regulatory and internal requirements
  • Detail a verification assessment and non routine monitoring to be undertaken when routine monitoring identifies a change in discharge characteristics which have the potential to alter existing characteristics and potential impacts of the discharge.

In 2021 and 2022 a detailed field based verification monitoring program was undertaken as per requirements of the OMDAMP. 

This included collection of water and sediment quality data at Woodside’s assets which discharge produced water. The aim of the program was to collect up to date information on produced water discharges and potential indicators of impact within the environment. This information contributes to the broader application of the OMDAMP and ensuring it remains a valid tool. It was also used to validate asset based environmental impact assessments.

The outcome of the monitoring program demonstrated continued compliance against regulatory and internal requirements for assets that discharge produced water.

It also provides verification of the effectiveness of the implemented controls over the life of the asset.