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Sequence Stratigraphy Outlining The Depositional History Of The Barrow Group, Barrow Sub-Basin, North West Shelf, Western Australia.

Duckett, Ashley K

Honours Degree, 1988

University of Adelaide

Abstract

The North West Shelf, Western Australia, is an area of relatively intense petroleum exploration activity, particularly in the Barrow Sub-basin. A number of commercial oil and gas discoveries have been made in recent years, reviving interest in the depositional history and stratigraphic trapping potential of the regressive Barrow Group sediments. This has been enhanced by seismic stratigraphic advances and improved seismic data quality over the past decade.

Excellent quality seismic control has enabled five Type 1 (Vail and Sangree, 1988) sequence boundaries to be identified from reflection termination patterns. Within each depositional sequence, bound by Type 1 sequence boundaries, a number of seismic facies were recognised and, following ties to well data, were found to represent individual depositional facies. These facies were also recognised in log sections, where available, and combined well and seismic data have been used to produce a stratigraphic cross section of the study area.

Each depositional sequence identified contained sedimentary facies representing highstand and lowstand systems tracts. Seismic facies representing basin floor fan, slope/channelled fan, lowstand prograding wedge, highstand prograding wedge and highstand fluvio-deltaic complex deposits have been recognised. For each depositional sequence identified, seismic facies distribution maps were produced and local feeder channel morphology identified with associated sedimentary sits.

Highstand fluvio-deltaic complex sands of all sequences have proven production capabilities. Basin floor fan sands associated with sequences A, B, and C exhibit significantly better reservoir properties than the basinal sands of sequence D. In the study area, no basin floor fan sands have produced commercial hydrocarbon flow rates. However, permit WA-192-P, to the north, contains the Harriet and Rosette oil fields, both reservoired in basin floor fan sands of sequences postdating those identified in the study area.

Australian School of Petroleum
THE UNIVERSITY OF ADELAIDE

SA 5005 AUSTRALIA

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