Detailed Sequence Stratigraphy Of The Latrobe Group , Gippsland Basin, Victoria.
Masters, Steven B.
Honours Degree, 1993
University of Adelaide
This project involves a six-well sequence stratigraphic analysis of Esso Regional Line Five, extending from Albacore #1 to Grunter #1 in the Gippsland Basin. The interpretation extends from the top of the Latrobe Group to the 68 Ma sequence boundary. Using primarily petrophysical well log and seismic information, seismic/sequence stratigraphic concepts have been applied to produce a detailed sub-surface interpretation.
Sequence stratigraphic and seismic stratigraphic analyses are valuable tools assisting the prediction of reservoir, source and seal geometries and distributions. As is the case with an interpretation project of this type, the position, extent and nature of depositional sequences represent a model indicative of the environments present, not necessarily an accurate sub-surface picture.
Fourteen key unconformities and ten different sequences have been identified in the study area, dominated by highstand and lowstand systems tracts. Erosional events have removed significant quantities of strata, therefore complete sequence preservation (lowstand-transgressive-highstand) is rare.
Rock units have been divided into nine different depositional environments: estuarine/marginal marine, fluvial, coastal plain, restricted marine, foreshore, shoreface, offshore marine, condensed sequences and volcanics. Nearshore marine and estuarine sandstones are the best reservoir facies, with transgressive marine shales potentially the best sealing units.
Structure is characteristic of the Gippsland Basin, displaying a series of normal faults. Episodes of canyon formation and fill are present, dominated by the Marlin Channel and the Tuna-Flounder Channel.
Two oil-producing wells are present in the study area, namely Mackerel #1 and Flounder #1. The potential for further hydrocarbon discoveries in the study area is good, the best prospects associated with rollover anticline traps.