Seismic geomorphology as a tool to explore the georesource potential of slope failures—examples from offshore North West Shelf, Australia. / Scarselli, Nicola; Bilal, Awad; McClay, Ken; Ferrer, Oriol; Gumprecht, Sasha; Paten, Thomas.

Interpreting Subsurface Seismic Data. ed. / Rebecca Bell; David Iacopini; Mark Vardy. Elsevier, 2022. p. 33-59.

Research output: Chapter in Book/Report/Conference proceedingChapter (peer-reviewed)peer-review

Published

Abstract

Modern seismic techniques are employed to investigate prime examples of slope collapse systems to infer evolutionary paths and to explore the potential of their products as petroleum system elements. The seabed failures presented in this work are located in the Exmouth Plateau (deepwater of North West Shelf of Australia) and affected Jurassic rift strata as well as near seabed, Late Oligocene to Recent, postrift sediments. The seabed collapse systems originated at water depths of ∼1000m and extend downdip to depths well in excess of 1500m. These exhibit a width in the range of 1–5km and extend downdip for ∼15km, with estimated volumes of sediments in excess of 10km3. A number of these failures are characterized by disrupted, slumplike facies, which progressively pass downslope into packages of high amplitude, continuous reflections. This facies transition is further investigated with attribute extractions showing a downslope rheological transformation from slump to mass-flow as evidenced by hundreds of meter-wide canyons that link the updip failures to well-developed, downdip fan systems several kilometers across. In the rift section, slope failures affected latest Triassic to Middle Jurassic planar, extensional domino-style fault systems in the form of well-imaged footwall degradation complexes. These failures exhibit overlapping, scoop-shaped scars up to 10km in length that deteriorated the exposed footwall breakaways. The degraded fault-scarps form erosional features with up to 1.8km of scarp retreat of the prerift Mungaroo Formation—a primary reservoir in the Exmouth Plateau. Debris from footwall collapse was resedimented in the hanging-wall basins, forming talus wedges up to 300m thick that taper away from adjacent fault planes for distances of several kilometers. These deposits are characterized by sheeted to contorted seismic facies, indicating a variety of mass-wasting processes accompanying footwall collapse. The generation of debrites and turbidites reservoirs as observed in composite “slump to mass-flow” failures, and also the capacity of these to redistribute and accumulate rift reservoirs into hanging-wall basins as seen in fault degradation complexes clearly indicate that slope failures have the potential of contributing to a diversity of hydrocarbon play types in rifted passive margins.
Original languageEnglish
Title of host publicationInterpreting Subsurface Seismic Data
EditorsRebecca Bell, David Iacopini, Mark Vardy
PublisherElsevier
Pages33-59
Number of pages27
ISBN (Print)978-0-12-818562-9
DOIs
Publication statusPublished - 2022
This open access research output is licenced under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

ID: 45844626