Resurrection at AGL Silver Springs and Wallumbilla: case study of bringing field and surface facilities back to life
John Croker A C , Matthew Kidd A B , Evie Nicola A and James Dean AA AGL Energy Limited, 200 George St Sydney NSW 2000, Australia.
B ICD (Asia Pacific) Pty Ltd.
C Corresponding author. Email: jcroker@agl.com.au
The APPEA Journal 57(1) 124-135 https://doi.org/10.1071/AJ16218
Accepted: 23 February 2017 Published: 29 May 2017
Abstract
AGL acquired the Silver Springs reserves and operations from Mosaic Oil in 2010, including several depleted yet condensate-rich gas fields. Gas was sent from Silver Springs to the Wallumbilla LPG plant (acquired by AGL in 2011) to be refined into sales gas, LPG and condensate. AGL’s objective was to build a commercial underground gas storage facility by converting the Silver Springs gas field into an underground storage reservoir. The business intent was to run the reservoir in alternating injection and withdrawal mode to take advantage of supply and demand economics.
Setting up for injection and withdrawal required the commissioning of 10 petroleum producing wells, bi-directional high-pressure flowlines and associated infrastructure. A high-pressure injection compressor was commissioned. Injection of dry sales gas into wells commenced in 2011. Withdrawal at a higher rate than original was facilitated by new separation and dehydration equipment.
The Wallumbilla plant was refitted extensively, including flare and venting upgrades and recertification of the pipeline and every pressure vessel on-site.
Withdrawal mode operations commenced in October 2015. The LPG plant operability was demonstrated; however, running at design rate was compromised by excessive chilling in the cryogenic section of the Wallumbilla plant, caused by lower than expected LPG quantities in the withdrawn gas. Process engineering work resulted in design of a regenerative heater to warm the sub-cooled gas.
The presentation covers the extent of the improvement work and the process investigations, which have formed the basis to ensure future versatile operation.
Keywords: cryogenic, expansion, LPG, process engineering, turbo-expander.
John Croker has 38 years of experience in process and hydrocarbon industries. Starting professional life with CSR, John has worked for Dow Corning on a number of international projects. John spend time at Wattyl, managing information at the corporate level and later at ICD as a specialist consultant. John came to AGL in 2015 and led the engineering of the Silver Springs projects through to completion. Sydney based, John and Helena his wife of 33 years have two sons and enjoy travel and adventure activities including rockclimbing, bushwalking and diving. John has a degree in Chemical Engineering from UNSW and is a Fellow of the Institution of Chemical Engineers and a Registered Professional Engineer in Queensland. |
Matt Kidd is a Senior Process Engineer with ICD (Asia Pacific) Pty Ltd, a specialist engineering consultancy in the oil and gas industry. After several years work on process design, process simulations and process safety jobs with Shell Refining and Caltex, Matt has worked at AGL at the project completion and commissioning stages of the Silver Springs and Wallumbilla project. Matt had a particularly strong involvement in the test running phase of Wallumbilla, verifying process design and re-establishing the operating envelopes. In so doing Matt developed the conceptual basis for much of the improvement work discussed in the paper. Matt has a BE degree in Chemical Engineering from Sydney University. |
Evie Nicola is a Senior Reservoir Engineer at AGL. She has 11 years of progressive experience in the oil and gas industry. Her professional history includes Reservoir and Production Engineering and Wireline Field Engineering at both AGL Energy and Schlumberger Oilfield services, respectively. Evie has a focus on production forecasting and well optimisation, reservoir simulation, well test planning and interpretation, well integrity monitoring and asset performance, and reservoir exposure – conventional oil and gas, gas condensate, gas storage, tight gas and CSG reservoirs. |
James Dean is the AGL Qld Operations Superintendent (and the appointed Operator under the PandG Act 2004) with close to 18 years’ experience in the industry and enjoying being a family man. James started at Silver Springs as a casual mechanic with Santos, then Mosaic Oil bought the asset and James started his full-time career in the industry. Mosaic sold the asset to AGL energy. AGL ran a project to transform the old Silver Springs and Renlim field in what we have today in the storage and withdrawal facility. During this time James developed an interest in photography and the local fauna and flora, especially the reptiles, particularly woma pythons. James was Senior Operator/Maintainer on-site during the project phase then took over as the Qld Operations Superintendent. |
References
Coffey Environments (2013). Environmental Management Plan: Recommissioning and Operation of the Wallumbilla LPG Facility. Available at: https://www.agl.com.au/-/media/AGL/About-AGL/Documents/ How-We-Source-Energy/Gas-Environment/Silver-Springs/Assessments- and-Reports/2013/9084_3_EMP_14052013.pdf?la=en [Verified 24 February 2017].RPS Australia (2010). Silver Springs Gas Storage Facility Environmental Management Plan. Prepared for AGL Gas Storage Pty Ltd. Available at: https://www.agl.com.au/-/media/AGL/About-AGL/Documents/How-We-Source-Energy/Gas-Environment/Silver-Springs/Assessments-and-Reports/2010/Silver-Springs---Environmental-Management-Plan.pdf?la=en [Verified 24 February 2017].
