Geoscience Visual Presentation G01: Establishing an integrated geoscience workflow to optimize well plug and abandonments in the Gippsland Basin
Natalie Debenham A * and Ngaire Long A *A
Natalie Debenham graduated from the Australian School of Petroleum at the University of Adelaide in 2019 with a PhD in structural geology and petroleum geoscience. Prior to this, Natalie completed a BSc (Hons) at the University of Adelaide in 2014 and MRes at Macquarie University in 2015. Natalie joined Esso Australia in 2019 and is currently working in the Gippsland Basin Production Team as a geoscientist for the Turrum Field and P&A activities across the Gippsland Basin. Natalie’s interests include reservoir characterisation and structural geology. |
Ngaire Long graduated from the University of Monash in 2001 with a BSc (Science Scholar) in Geology and Chemistry and BSc (Hons) in Geochemistry. Ngaire joined Esso Australia in 2002 working in various exploration and production roles across the Gippsland Basin and Papua New Guinea. Following this Ngaire worked as a development geologist for GDF Suez based in London, UK, focused on the Southern North Sea, and for Santos based in Perth, Australia, focused on the Carnarvon and Bonaparte basins. Ngaire returned to Esso Australia in 2023 and is currently working as a geoscientist for the Tuna field and P&A activities across the Gippsland Basin. Ngaire’s interests include the integration of subsurface and production datasets, working with and communicating geoscience ideas to other disciplines. |
Abstract
Geoscience Visual Presentation G01
Well plug and abandonment (P&A) is the process of permanently sealing and abandoning a hydrocarbon reservoir, and any required shallow formations, prior to title surrender. As some of the Gippsland Basin assets have reached end-of-field life, platform decommissioning requirements have led to a significant increase in P&A activity. The scale of this P&A activity has provided the opportunity to establish a standardized workflow for geoscience support to the P&A design process. Utilising this integrated geoscience workflow during early assessment screening can optimize individual well P&A designs, resulting in efficiencies to the well planning, regulatory approval, and execution stages. The three key pillars of geoscience assessment for P&A design are shallow hazards identification, cap rock definition and mechanical rock strength assessment. Working as an integrated team of geoscientists, wells engineers and reservoir engineers, these assessments have been successfully used in the Bass Strait to reduce complexity in P&A design and execution, while working within regulatory expectations for permanent abandonment. With over 150 well P&As already completed, and over 200 wells associated with the Campaign 1 decommissioning project, integrating the geoscience input early in the P&A design process is expected to drive better outcomes in overall execution efficiency. This can result in less complex and safer rig operations, with incremental savings on a well-by-well scale expected to deliver impactful cost savings in the overall decommissioning scope. The workflow also provides a consistent approach in engaging with the regulator and meeting evolving regulatory requirements.
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Keywords: caprock, decommissioning, geoscience workflow, Gippsland Basin, mechanical rock strength, plug and abandonment, shallow hazards.
Natalie Debenham graduated from the Australian School of Petroleum at the University of Adelaide in 2019 with a PhD in structural geology and petroleum geoscience. Prior to this, Natalie completed a BSc (Hons) at the University of Adelaide in 2014 and MRes at Macquarie University in 2015. Natalie joined Esso Australia in 2019 and is currently working in the Gippsland Basin Production Team as a geoscientist for the Turrum Field and P&A activities across the Gippsland Basin. Natalie’s interests include reservoir characterisation and structural geology. |
Ngaire Long graduated from the University of Monash in 2001 with a BSc (Science Scholar) in Geology and Chemistry and BSc (Hons) in Geochemistry. Ngaire joined Esso Australia in 2002 working in various exploration and production roles across the Gippsland Basin and Papua New Guinea. Following this Ngaire worked as a development geologist for GDF Suez based in London, UK, focused on the Southern North Sea, and for Santos based in Perth, Australia, focused on the Carnarvon and Bonaparte basins. Ngaire returned to Esso Australia in 2023 and is currently working as a geoscientist for the Tuna field and P&A activities across the Gippsland Basin. Ngaire’s interests include the integration of subsurface and production datasets, working with and communicating geoscience ideas to other disciplines. |
