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GRIFFIN, ANGELA G., University of Waikato, Department of Earth Sciences, Hamilton, New Zealand

ABSTRACT: High Resolution Sequence Stratigraphy Using Geophysical Logs with Well-to-Well-Outcrop Correlation for Reservoir Delineation in Late Miocene Marine Deposits

The goal of this research project is to develop a wireline-log model for the shelf sequences evident in Manutahi-1 (Taranaki Basin), which was continuously cored, and apply this model to electric logs available for a suite of neighbouring wells, to better delineate reservoirs in regressive sandstone units.

During the Late Miocene-Pliocene, Taranaki Basin, which is the only hydrocarbon productive basin in New Zealand, developed a distinct progradational shelf to slope succession. The Matemateaonga Formation of Late Miocene age beneath Taranaki Peninsula represents the shelf succession. The formation is characteristically cyclothemic, as shown by facies analysis of the continuously cored succession in Manutahi-1. The Manutahi-1 hole also has a good suite of wireline logs (gamma ray, resistivity, spontaneous potential and sonic velocity), presenting an opportunity to develop a wireline log model for the shelf sequences defined independently by facies analysis.

This project involves high resolution correlation of the wireline logs northward (up dip) and southward (down dip) from Manutahi;n-1 to neighbouring holes and wells. This will allow for correlation of the wells at the sequence and systems tract level. To achieve this, computer manipulations of digital copies of wireline logs, field analysis (lithostratigraphy, sequence stratigraphy, facies analysis) and computer aided drafting will be used.

The application of this work relates to subsurface delineation of reservoir units. The obvious reservoir units are well-sorted siliciclastic inner to mid shelf sandstone units that accumulated during the falling stage of sea level cycles (regressive systems tracts).

AAPG Search and Discovery Article #90909©2000 AAPG Foundation Grants-in-Aid