Concurrent 6. Presentation for: Effects of rapid gas decompression on coal seam gas swellables
Jan Bon A *A Petrolab Australia Pty Ltd, 45 Woodforde Road, Magill, SA 5072, Australia.
The APPEA Journal 62 - https://doi.org/10.1071/AJ21319
Published: 3 June 2022
Abstract
Presented on Tuesday 17 May: Session 6
Thousands of non-stimulated coal seam gas (CSG) wells in Queensland’s Surat Basin rely on swellable packers as the first line of defence against interburden solids production and poor well run life. This paper is aimed at understanding some of the impacts of long-term well operations on swellable performance from rapid changes in downhole pressure. For the first time, rapid gas decompression (RGD) effects on CSG swellables were experimented on in a quantitative manner as an analogue to underbalanced workover and pump trip conditions. RGD has the potential to break down swellables due to rapid release of high-pressure methane diffused in the rubber matrix resulting in a flow path for interburden solids. Five commonly available swellables from the CSG market were lab-tested for rapid decompression with methane at operational conditions. Coupon samples were swollen to representative conditions and placed in an autoclave under high-pressure methane, then rapidly decompressed in cycles. Results of this study showed relatively low levels of physical degradation under test conditions but shrinkage effects varied between products largely grouped into material properties, confirmed with separate ambient shrinkage test. As such, the focus on swellable placement geometry remains paramount.
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Keywords: borehole geometry, CSG, decompression, de-swell, interburden, isolation, rapid gas decompression, RGD, shrinkage, swellable, swellable packer, underbalanced workover.
Jan Bon obtained his Bachelor of Engineering in Petroleum Engineering from the University of New South Wales and his PhD from the Australian School of Petroleum, the University of Adelaide. He is a committee member of SPE South Australia. During his time in academia, his research work related to miscible phase behaviour of reservoir fluids with CO2 relating to the injection of CO2 for sequestration and enhanced oil recovery. He has previously worked as a Senior Reservoir Engineer at Santos Limited working on development of volatile oil and gas condensate reservoirs of the Cooper Basin and screening of oil reservoirs for carbon capture and storage. Since 2013 he is the Manager of Petrolab Australia, specialising in the sampling and PVT analysis of reservoir fluids, including phase behaviour, flow assurance and miscibility studies at reservoir conditions. |
