--> ABSTRACT: Teak - Testing a Subsalt Hydrocarbon Trap Geometry, South Timbalier Block 260, Gulf of Mexico, by F. C. Snyder and J. A. Nugent; #91019 (1996)

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Teak - Testing a Subsalt Hydrocarbon Trap Geometry, South Timbalier Block 260, Gulf of Mexico

F. C. Snyder and J. A. Nugent

The Phillips Petroleum South Timbalier South Addition 260 #1 well, Teak prospect, tested a subsalt closure covering parts of three offshore blocks. The structure was formed by the truncation of southeast dipping strata on the north and west by salt welds. These welds, are collapsed salt feeder systems that were the conduits for emplacement of the salt sheet overlying the Teak prospect.

The well encountered eight hydrocarbon shows over 5,000^prime of subsalt section in predominantly thin-bedded turbidite sandstones. Pay intervals are confined to a zone directly below the salt and deeper in the section below an unconformity surface. Salt welds proved to be sealing surfaces, but other parameters also influenced the vertical distribution of hydrocarbons. The hydrocarbons trapped directly below the salt are within a tectonically disturbed zone where reservoirs probably have limited lateral continuity. The deeper unconformity trap is interpreted as an older subhorizontal salt weld below the present-day salt sheet because of missing stratigraphic section and the presence of a condensed section above it.

A tectonic model for the area indicates three phases of salt movement. The first phase was a near-vertical emplacement of areally-restricted, wedge-shaped salt massifs downslope to large, stepped, counter-regional faulting. This phase was followed by rapid deflation of the massifs and lateral spreading of the salt due to sediment loading. This emplaced the salt over Teak and formed the bounding weld surfaces. Finally, a period of thin-skinned extension remobilized the salt sheets into secondary piercements and formed sub-horizontal welds extending away from the present Teak salt sheet.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California