Mondarra Reverse Bypass Project
GPA was engaged by APA to provide pre-FEED and eventual detailed design of modifications to their Mondarra Gas Storage Facility (MSF).
The project, known as the Reverse Bypass Project, entailed modifications to APA’s existing MSF to enable the compressor units to provide firm gas flow service from the Parmelia Gas Pipeline (PGP) to the Dampier to Bunbury Natural Gas Pipeline (DBNGP) without reducing the current nameplate capacity of the MSF to continue providing its existing injection, withdrawal, and bypass services.
The aim of the new reverse bypass capability is to allow APA to provide a transportation service for natural gas from the new gas field developments in the Perth Basin to gas users connected to the DBNGP and Northern Goldfields Interconnect (NGI).
To enable the additional functionality the below key components and modifications needed to be made to the facility:
- Addition of Filtration System for gas imported from PGP.
- Addition of low-flow control valves for gas flow to/from DBNGP.
- Addition of Y-Strainers on drains from the Injection Filter/Coalescer and Production Filter/Coalescer to the Closed Drains system.
- Enabling gas flow from PGP Metering Skid to Suction Header.
- Addition of pressure control valve on the Silica Gel Package outlet to enable diversion of Withdrawal gas around the compressors (i.e. Withdrawal without compression) and for future functionality.
- Replacement of PGP Flow Control Valve to suit bi-directional flows.
- Field Equipment Room (FER) tie-ins of new cables, modification of existing control systems to control and monitor the items above and commissioning of the changes.
GPA was engaged by APA in 2023 to assist in the Pre-FEED phase of this project. Upon successful execution of the Pre-FEED, in October 2023 the APA team was given financial approval to proceed and engaged GPA to undertake complete multidiscipline detailed design, procurement support, offsite construction support and commissioning support to the project. The detailed design phase was subsequently compressed to allow an earlier start to the construction and commissioning phases, whilst incorporating a further 38% of approved scope changes. GPA successfully completed the total detailed design scope in October 2024, meeting the revised schedule commitments and coming within 9% of the final budget.
This achievement has enabled APA to successfully meet its tight construction and commissioning milestones to successfully deliver this project. GPA is currently assisting APA to complete the commissioning phase of the project.
