Safely retiring offshore assets for Chevron’s Thevenard Island project.
Chevron Australia required a full decommissioning and remediation of ageing offshore infrastructure at Thevenard Island (TVI). The project involved safe retirement of platforms, environmental restoration, and management of hazardous and Naturally Occurring Radioactive Material (NORM) under strict regulatory standards.
Client
Chevron Australia
Type
Decommissioning, NORM
Location
Onslow Marine Support Base, Western Australia
At a glance
- Chevron Australia needed a full decommissioning and remediation of ageing offshore infrastructure
- ASCO implemented a fully managed NORM and hazardous materials services including site optimisation, on-site training and advanced monitoring
- The project delivered safe, incident-free processing of NORM-contaminated materials and seamless coordination across onshore and offshore operations
Approach
Decommissioning oil and gas assets demands precision, expertise, and careful planning. We combined strategic oversight with hands-on execution, assessing the full scope of activities—from dismantling and removing nine offshore platforms to processing materials at OMSB. Critical risks included hazardous materials, radiological exposure, and logistical complexity.
The biggest challenge was the safe, efficient, and compliant handling of contaminated materials at the Onslow Marine Support Base (OMSB), the logistical hub for offshore decommissioning operations.
- Deploying Radiation Safety Officers and establishing supervised processing areas
- Optimising site layouts and embedded radiation monitoring protocols
- Controlled offloading, size reduction, and storage of NORM-contaminated materials
- On-site NORM awareness training, continuous risk assessments, and advanced monitoring/reporting systems for transparency and traceability
Impact
Our approach delivered safe, incident-free processing of NORM-contaminated materials and seamless coordination across offshore and onshore operations. Processes that were previously high-risk are now fully controlled, efficient, and compliant. Teams gained enhanced capability in radiation safety and decommissioning workflows, ensuring readiness for future projects.
Environmental restoration targets were met, returning the OMSB and TVI to nature reserve standards. Optimised workflows and embedded expertise also reduced labour mobilisation costs and maintained project schedules.
- Zero incidents during NORM handling and processing
- 100% regulatory compliance in radiation safety and hazardous material management
- Enhanced workforce capability through training and knowledge sharing
- Environmental stewardship achieved through proper remediation and waste management