The West Erregulla gas discovery. Implications for an extensive Permian play fairway across the onshore northern Perth Basin, Western Australia
A. Cortis A , A. Farley A C , D. Lewis A , S. Cheong A , A. Chia B and W. Zhang AA Strike Energy Limited, Exploration Team, Thebarton, Australia.
B Strike Energy Limited, Drilling and Completions Team, Thebarton, Australia.
C Corresponding author. Email: andrew.farley@strikeenergy.com.au
The APPEA Journal 61(2) 594-599 https://doi.org/10.1071/AJ20034
Accepted: 12 March 2021 Published: 2 July 2021
Abstract
The West Erregulla field is a significant new discovery in the northern Perth Basin that expands the play fairways for the basal Triassic/late Permian sandstones of the Dongara/Wagina formations and early Permian sandstones of the Kingia/High Cliff formations. The 2019 discovery well, West Erregulla-2, targeted three stacked seismic amplitude anomalies interpreted to be gas-charged conventional sandstones at depths between 4100 m and 5000 m. Gas charge is confirmed in all three units. Gas is hosted in linked, reactivated Permian-aged fault blocks located in the axial part of the Dandaragan Trough. They represent a down-dip analogue to the Waitsia gas field NW of West Erregulla. Only the Kingia sandstone was tested in West Erregulla-2. It contains good to excellent quality reservoir with >55 m of pay averaging 12.6% porosity and gas saturations of 65%. Despite deep burial, porosity of the reservoirs was retained by a combination of syndepositional clay coatings and early burial gas charge. Testing of this zone achieved a maximum sustained flow rate of 69 mmcf/day. Wireline logs and seismic mapping suggest the presence of a large gas field with gross gas column height of >200 m over an area of ~40 km2. Scoping volumetric estimates using a range of possible gas water contact (GWC) suggest a P50 in-place original gas in place (OGIP) of ~1182 Bcf for the Kingia formation (informal name). The West Erregulla, Waitsia and Beharra springs deep fields contain significant gas resources. Their spatial distribution suggests the existence of a deep, regional Permian fairway that could cover a large portion of the Perth Basin.
Keywords: northern Perth Basin, Kingia formation, deep gas, clay coatings.
Anthony (Tony) Cortis is a Professional Geologist and principal in Igesi Consulting Inc based in Canada. He holds a B.Sc. in Geology from Laurentian University and M.Sc. in Geology from the University of Manitoba. His company provides integrated upstream and venture management consulting to clients. Previously he worked 28 years for both Shell Canada and Royal Dutch Shell in various roles both in Canada and worldwide. These roles included prospect and play generation, research into sediment forcing, specialist studies of troubled assets, carbonate development, internal consulting, unconventional oil and gas plays and venture general management. His last positions were General Manager Jinqiu Venture, Sichuan, China and Exploration Venture Manager for Myanmar. Tony has worked closely with Strike Energy Ltd since 2017 and has been part of teams evaluating both deep coals in the Cooper Basin and the North Perth Basin. |
Andrew Farley graduated from the University of Newcastle (Australia) in 2002 with a B.Sc in Geology. He has 19 years of experience working with onshore oil and gas operators on exploration and development projects in all 5 mainland states of Australia. Prior to joining Strike Energy in 2012, Andrew worked with AGL Energy in Sydney. Since joining Strike in 2012, Andrew has held a number of technical positions, becoming Exploration Manager in September 2019. Andrew has been a key member of the Strike team during the design and execution of the Jaws Project in the Cooper Basin, and more recently the West Erregulla discovery in the Perth Basin. |
David J Lewis is a Professional Geophysicist and principal in David J Lewis Consulting Inc based in both Calgary, Alberta and Peachland, British Columbia in Canada. His company provides complete seismic and quantitative interpretation services to clients. Previously he has worked 37 years for both Shell Canada and Royal Dutch Shell in various roles including seismic acquisition, processing, quantitative interpretation, prospect and play generation both in Canada and worldwide. His last position was Seismic Interpretation Coad for unconventional assets, Shell Americas. |
Sharon Cheong is presently a Senior Reservoir Engineer at Strike Energy Limited with 15 years of experience in the oil and gas industry. Sharon holds a Bachelor of Chemical Engineering and Master of Petroleum Engineering degree (University of Adelaide). She is an SPE member and past SPE committee member (South Australian Sector). Sharon began her graduate years in processing roles at BHP and ExxonMobil however, most of her career was at Santos as a development reservoir engineer and fracture stimulation engineer working in conventional and unconventional Cooper Basin gas fields. Sharon joined Strike Energy’s Exploration team in 2019 and works mainly on field development and exploration activities in the Perth and Cooper Basins. |
Andrea Chia is a Petroleum Engineer at Strike Energy currently working on assets in the north Perth basin. She holds a bachelor’s degree in Petroleum Engineering and Science, majoring in geology and geophysics from the University of Adelaide. Andrea has 8 years of experience in the oil and gas industry and previously worked for Santos Limited in Reservoir Engineering and Production Engineering roles across multiple oil and gas fields in the Cooper Basin. Andrea is a committee member of the Society of Petroleum Engineers, SA chapter. |
Dr Wenxia Zhang has over 28 years of experience as a reservoir engineer working in the oil industry for Shell USA, Shell International, Amoco Production Company and CNPC. She has received three degrees in Petroleum Engineering; a B.Sc. from Northeast Petroleum University, China, an M.Sc. from Montana Tech and a PhD from Pennsylvania State University. She has extensive Reservoir engineering evaluation experience in oil and gas appraisal and exploration in offshore deepwater, unconventional, and onshore conventional plays. She has particular expertise in well test analysis, production decline analysis, well and reservoir integration management and reservoir engineering support to well drilling and completions. |
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