Reifenstuhl, Rocky R.1, Donald W. Brizzolara2
(1) Alaska Division of Geological & Geophysical Surveys, Fairbanks, AK
(2) Alaska Division of Oil and Gas, AK
ABSTRACT: Alaska Peninsula and Bristol Bay: Frontier Oil and Gas Basin
The Alaska Peninsula-Bristol Bay region is a frontier basin in southwest Alaska: 500 miles long and up to 100 miles wide. The northwestern part of the peninsula is underlain by up to 18,000 feet of Tertiary sediments that thicken northwestward into the Bristol Bay basin. Gently folded Mesozoic and Tertiary sediments, and Quaternary volcanoes cropout on the southeastern peninsula. The offshore Bristol Bay basin is a sediment-filled structural depression that underlies the northern continental shelf of the Alaska Peninsula
Prior to 1925, eight shallow wells were drilled near two seeps. Eighteen wildcat wells, 5,000 to 15,000 feet deep, were drilled on the peninsula for Mesozoic or Tertiary prospects. Many wells had significant gas shows (coalbed methane; thermogenic). Oil shows occurred in three Point Moller region wells. In 1983, ARCO drilled in federal waters the North Aleutian COST #1 well (17,000'TD). In 1985 the Amoco Becharof #1 well showed significant gas in the Tertiary section. No wells to date have flowed commercial quantities of oil.
Northern coastal plain hydrocarbon potential is moderate to locally high for gas; low to moderate for oil, in structural and stratigraphic traps. Oil and gas seeps occur along the peninsula's southeastern flank; some along large anticlinal crests. Source rock data indicate gas prone Tertiary organic shales. Oil may be derived from deeper Mesozoic strata. Tertiary and Mesozoic sandstone reservoir characteristics are locally conducive to hydrocarbon production.
State and Native land owners are currently pursuing a new hydrocarbon lease program. AKDGGS is engaged in basin analyses.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.