ABSTRACT: A Depositional Model for the Early Eocene D Sands Reservoir of Maui Field, Taranaki Basin, New Zealand

BEGGS, J. M., DSIR Geology and Geophysics, Lower Huff, New Zealand, I. D. BRYANT, Shell Todd Oil Services, New Plymouth, New Zealand, and D. T. POCKNALL, Amoco Production Co. Ltd., Houston, TX

Maui field offshore Taranaki is New Zealand's largest known hydrocarbon resource. Production is from two intervals. The lower, D Sands interval, at about 3100 m, has been cored in two wells 14 km apart. Sedimentological features of the core are integrated with palynofacies results and dipmeter and other wireline information to construct a two-dimensional conceptual model for the reservoir architecture, which will be tested by development drilling in 1992.

The D Sands interval is capped by a marine shale deposited following a fieldwide transgression, represented by a basal condensed section. The uppermost sand unit is interpreted as a transgressive inner shelf unit formed by drowning of a coastal barrier. Below that unit, are significant lateral facies changes across the field. The northeastern "A" area comprises predominantly fluvial environments except for a marine tongue that does not extend as far as the southwestern "B" area. The latter area is dominated by estuarine facies, including thick channel point bar units, above a basal coal-bearing flood-plain unit. The shoreline trend shifted from a west-east to a southwest-northeast orientation during the D Sands interval, with the establishment of a substantial tidally influenced incis d valley drainage system in the southwestern area. Depending on the distribution of sealing units, there may be exploitable hydrocarbon pools in the lower D Sands.

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)