Abstract: Geologic and Operational Summary of COST B-2 Well--Appraisal of First Deep Stratigraphic Test Drilled on U.S. Atlantic Outer Continental Shelf

Roger V. Amato, Michael A. Smith, Malcolm A. Furbush, John A. Lees

The Continental Offshore Stratigraphic Test (COST) B-2 well was drilled in the Baltimore Canyon Trough to obtain geologic, geochemical, and geophysical information for assessing the petroleum potential of this sedimentary basin. The well was drilled with the semisubmersible rig, SEDCO J, 91 mi (146 km) east of Atlantic City, New Jersey, in Block 594 (BLM Map N.J. 18-3) at lat. 39°22^prime31.972^PrimeN, long. 72°44^prime03.871^PrimeW in 90 m of water. Drilling began in mid-December 1975 and ended in late March 1976 at a TD of 4,890 m.

The COST B-2 well penetrated about 1,400 m of terrigenous to deep-water marine sandstone, shale, and limestone of Tertiary age; about 945 m of predominantly marine Upper Cretaceous sandstone and shale; and about 2,408 m of Lower Cretaceous shallow-water marine to terrigenous sandstone, shale, and coal. The Tertiary-Upper Cretaceous boundary is at 1,524 m and the top of the Lower Cretaceous at 2,478 m. The well bottomed in lowermost Cretaceous (Berriasian) rocks. Nearly 610 m of sandstone with average porosity exceeding 25% is present between 1,524 and 3,353 m and forms good potential reservoir rocks. Most of these beds appear to be sealed adequately by shales and carbonate rocks. Geochemical analysis indicates organic-rich, fine-grained potential source rocks between depths of 2,865 a d 4,237 m. Studies of thermal maturity indicate that if these rocks were exposed to greater temperature alteration they could generate large quantities of gas and related liquids.

AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC