Pressure control of GLNG gas pipeline compliant with Australian standard requirements

• Pressure control system of GLNG pipeline.
• Pipeline is requiring adequate overpressure protection compliant with AS requirements.
• Pipeline potential overpressurization caused by elevation profile and hydrostatic head.
• Critical conditions as settle out and low flow analyzed.
• Primary and secondary system setpoints determined through transient hydraulic simulations.

The GLNG Consortium, formed by Santos, Total, Petronas and Kogas, is planning a large scale development to extract coal seam gas (CSG) from existing and future fields in the Roma, Fairview and Arcadia Valley area (Queensland, Australia) and to supply that gas for commercial sale and/or conversion to liquefied natural gas (LNG).A gas transmission pipeline called the “GLNG Pipeline” is a major component of the development. The GLNG Pipeline will be approximately 420 km in length and will be used to transport (CSG) from the existing and future fields to an LNG processing facility at Curtis Island near Gladstone (LNG Plant).Three inlets are foreseen in the initial pipeline section:
• F-PCS-01 at KP0
• Future F-HCS-05 at KP12.4
• Future A-HCS-01 at KP52.3The detail engineering phase of the pipeline is under completion, and the construction activities have already started in 2013. Saipem is in charge for both activities.This paper describes the process and flow assurance related characteristics of the GLNG Pipeline pressure control system developed during detail engineering, compliant with the requirements established by the adopted design standard, i.e. AS2885.1. The control system, ensuring adequate overpressure protection, allows a safe operation taking care of envisaged pipeline operating pressure, close to MAOP, and downward slope, causing risk for excessive pressurization of lower downstream sections.