--> ABSTRACT: The Southern Bonaparte Gulf, Northwest Australia--New Exploration Plays, by M. V. Dauzacker, J. M. Durrant, R. France, T. Nilsen; #91003 (1990).

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ABSTRACT: The Southern Bonaparte Gulf, Northwest Australia--New Exploration Plays

M. V. Dauzacker, J. M. Durrant, R. France, T. Nilsen

Integration of regional exploration data with new basin model concepts has generated new exploration plays in the offshore area defined as the Southern Bonaparte Gulf. This area represents a unique hydrocarbon habitat significantly different from adjacent areas. Early exploration (seven wells), targeting structural highs, encountered numerous hydrocarbon shows.

Of most recent significance, Turtle-1 (1984) targeted a midbasin, MS-I high recovering degraded oils in the MS-III section. Turtle-2 (1989) tested an additional 320-m-thick, MS-II onlap, encountering within fractured intervals significant oil and gas influx accompanied by massive lost circulation. Significant live oil (nondegraded) was produced on test despite formation damage inflicted during the 14-day well control period.

Within the MS-III section, thin incompetent seals and meteoric waters have resulted in small, degraded, low-GOR (gas/oil ratio) oil accumulations. In contrast the MS-II section has competent seals and exhibits high-GOR live oil. In consequence, given suitable models for porosity development, MS-II is highly prospective, indicating new exploratory plays: (1) MS-II fractured, stratigraphic pinch-outs flanking MS-I structures, (2) MS-II stacked turbidites and basin floor fans deposited in salt withdrawal subbasins, (3) MS-II carbonate banks within the subbasin's marginal carbonate complexes, (4) MS-I reefs localized over early salt structures and onlapped by MS-II sediments, and (5) MS-II structural and stratigraphic traps associated with diapiric salt.

By virtue of the stratigraphic and structural relationship of MS-II sediments, generally onlapping the flanks of the structural highs originally targeted, these new plays have not been tested in optimal locations. A new phase of exploration specifically targeted at these plays is planned.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990