New gas field tie-back

The Situation

The client's new gas field is an integral part of the development plan to supply gas to a Liquefied Natural Gas (LNG) project, and is planned to provide gas resource and gas deliverability to the gas plant in the PNG highlands.

The remote well site and challenging terrain strongly influenced the development requirements. Key challenges to overcome included:

• More than 900 metres elevation change along the pipeline route, descending to the river valley before climbing steeply to the gas plant

• An active fault for the pipeline to cross

• Constraints imposed by the existing plant

• High reservoir pressures leading to low flowing temperatures during start-up

• Brownfield constraints for tie-in at the gas plant

• The work needed to be defined within the constraints of the existing environment and infrastructure.

The field trip to the site highlighted the steepness of the existing pipeline easements and soil stability issues. The steep terrain and poor soil stability required specialised construction techniques to be employed – conventional pipelay methods would have been impractical and unsafe.

Approach

Advisian assembled a team able to address all aspects of the project. Our team combined technical skills for rigorous evaluation of the project, with the project execution skills to address the logistics and construction challenges associated with a remote location and steep terrain.

Our services included:

• Flow assurance to assess the flow behaviour of the pipeline tie-back to the gas plant

• Materials of construction and corrosion management

• Pipeline construction

• Logistics

• Geotechnical services

• Project costing and scheduling

• Brownfield construction and execution

• Remote site telemetry

We worked closely with the client’s site team to capture knowledge from the foundation project and incorporate this into the overall design.

Results

• Advisian brought the required expertise to the development, allowing the project to be promptly sanctioned and funded.

• The comprehensive conceptual design package enabled work to proceed, meeting the required execution timing to bring additional gas resources on-line for the project.

• Major design issues were comprehensively addressed in the concept phase, setting a firm basis for the development and hand over to the delivery team.