Print this pageAAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Seismic Geomorphology of a Tertiary-Aged Isolated Carbonate Platform System, Browse Basin, Northwest Shelf of Australia: The Spatial and Temporal Evolution of Carbonate Platform Environments I – The Lower Section
(1) Chevron Energy Technology Company, Houston, TX.
Three-dimensional seismic data from the Torosa Field (Torosa 3D Survey) in the Browse Basin of the Northwest Shelf, Australia, display a series of well imaged isolated carbonate platforms that allow the documentation of platform evolution from initiation to terminal drowning. The application of seismic geomorphology allows recognition of various carbonate geomorphic elements (depositional and diagenetic) including prograding margins, slope deposits, platform interior patch reefs, and karst fabrics. A variety of techniques integrating seismic geomorphology and seismic stratigraphy have been applied to assist in visualization of these deposits. Examples of workflows and techniques including horizon slicing, optical stacking, and facies mapping, along with evaluation of seismic section views will be illustrated.
This presentation will focus on the lower part of the carbonate succession. The carbonate factory is initiated through nucleation on a subtle pre-existing structural high. Initially, the carbonate system is characterized by a linear platform that is associated with progradation marked by clinoform geometry in both directions, suggesting a platform with no direct connection to the Australian continent. A succession of linear shoals characterizes the platform tops in the lower part of this buildup succession. Discrete depositional elements such as washover channels, washover fans, small pinnacle reefs, and coalesced interior platform buildups are observed. Some of the platforms margins are associated with broad reef development. Numerous flooding events punctuate the platform evolution, with each drowning event immediately preceded by deposition of clusters of small patch reefs, each less than 300m wide.