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Industry bid aggressively in OCS Sale 42, spending $816 million. Eight wildcats were drilled in 1981-82 to test 5 major plays. All wells were dry; no potential reservoir or source rocks were found.
The tectonic-stratigraphic framework of the Georges Bank basin is that of an Atlantic-type plate margin. Two major unconformities divide the section into prerift, synrift, and postrift sequences. The prerift sequence consists of Paleozoic metasediments in basement fault blocks. Synrift sediments consist of Newark Group equivalents: the Argo Salt and the Iroquois Formation. The postrift sequence consists of Mohican red beds overlain by progradational wedges, with the carbonate Abenaki Formation at the base.
The objective in 4 of the 8 wildcats was the Iroquois Formation. Mobil 312-1 and Shell 357-1 were drilled into a seismic anomaly interpreted to be a reef. This structure was found to be a complex carbonate mound. Exxon 975-1 was drilled on a seismic amplitude anomaly variously interpreted to be the result of salt, coal, or porous carbonates. This anomaly proved to be caused by a salt bed. The objective in Shell 410-1R was carbonate banks over a basement horst block. No significant zones of porosity were found.
The remaining 4 wildcats were drilled on Abenaki prospects. Mobil 273-1, Tenneco 187-1, and Conoco 145-1 were drilled for possible carbonate banks over a salt structure. Only thin oolitic grainstone intervals were found. Exxon 133-1 was based on a seismic anomaly interpreted to be a patch reef. This feature was found to be a volcanic cone.
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