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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 64 (1980)

Issue: 9. (September)

First Page: 1553

Last Page: 1554

Title: Morphology of Turbidite-Channel Reservoirs, Lower Hackberry (Oligocene), Southeast Texas: ABSTRACT

Author(s): Robert R. Berg, Brian K. Powers

Article Type: Meeting abstract


Gas is produced from Hackberry sandstones at depths from 9,500 to 11,500 ft (2,900 to 3,500 m) in the western part of the Hackberry embayment. Adjacent shales contain a microfauna generally believed to represent bathyal depths. The Hackberry sandstones are turbidites in the form of dip-trending, channel-like bodies. Recent cores from fields in southeast Texas provide more details concerning reservoir character and morphology.

Hackberry reservoirs are found in narrow channels only 3,000 to 4,000 ft (914 to 1,219 m) in width. Channel sandstones thicken abruptly to 200 to 300 ft (61 to 91 m). Middle-channel locations are characterized by stacked, massive sandstones which represent the A division of the turbidite sequence. Stacked channel beds are about 10 ft (3.5 m) thick, but no intervening shales separate bed sets. The channel-margin sections consist of interbedded sandstone and shale. The beds are 3 to 5 ft (1 to 1.5 m) thick and consist of massive and laminated sandstones that form turbidite sequences of the A and

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AB type. The adjacent overbank sections are composed dominantly of shale but contain thin sandstones and siltstones that are massive to laminated and rippled, and form more complete turbidites of the ABC type. All sandstones have graded texture and are volcanic-chert arenites of moderate quartz content.

The channels appear to be of constructional origin, and log correlations above and below the channel facies suggest that they are inserted in the sedimentary section rather than filling eroded channels. The several facies illustrated by cores have characteristic responses on borehole logs which permit recognition of channels and overbank sections by logs alone. These distinctive log characteristics may permit the prediction of channels in exploratory and development drilling.

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