Post-lease sale exploraton of the Navarin Basin, Bearing Sea, Alaska
Although the basin had optimistic beginnings, interest in further exploration of the Navarin Basin is waning because of disappointing d r i g results. Eight exploratory wells were drilled in the Navarin Basin in the year following Lease Sale 83 in 1984. All of these wells tested Tertiary fill that drapes or folds over simple, broad basement highs. Significant reservoir rocks were absent in all of these wells. Immature to mature Eocene kerogen with possible hydrocarbon-generating characteristics was found in a stratigraphic test well and two exploratory wells located on the flanks of the Pervenets subbasin. However, no signs of oil or oil migration were evident. A third exploratory well d r i ed on the southeast flank of the Pinnacle Island subbasin encountered thermogenic gas from a thin, probably lenticular Paleocene sandstone. The gas was probably sourced from interbedded, resinous coal. The geologic information collected from seven of the eight exploratory wells has now been released to the public. Of the leases acquired in Sale 83, 74 percent have been relinquished as of January 1988.
Review of Petroleum Geology of Anadyr and Khatyrka Basins, USSR
Two sedimentary basins bordering the Bering Sea in northeastern Siberia, the Anadyr and the Khatyrka, have been the targets of recent Soviet exploration for oil and gas. Drilling in the Anadyr basin has produced noncommercial quantities of gas and condensate from Tertiary volcaniclastic rocks. The Anadyr basin lies due west of Norton basin, a large unexplored sediment-filled Tertiary basin that underlies Norton Sound. Geologically, Anadyr basin lies between a late Mesozoic belt of volcanic and plutonic rocks similar to the Sierra Nevada of California and a complex foldbelt on the south that is structurally and lithologically similar to Franciscan terrane of the California Coast Ranges. Less extensive exploration in the Khatyrka basin has discovered only noncommercial quantities of oil and gas. The Khatyrka basin extends offshore between Capes Rubicon and Navarin near the northwest end of the Navarin basin on the Bering Shelf, and contains Tertiary sediment deposited within a structurally complex Mesozoic foldbelt that parallels the edge of the continental shelf.
Preliminary report on the regional geology, oil and gas potential and environmental hazards of the Bering Sea shelf south of St. Lawrence Island, Alaska
The Bering Sea shelf is underlain by at least 11 basins that are prospective sites for hydrocarbon accumulations. These basins encompass a combined area over 546,000 km/sup 2/ (211,000 mi/sup 2/), larger than the size of the state of California. Geophysical data indicate that two of the basins (St. George and Navarin) contain more than 10 km (6.2 mi) of Upper Cretaceous and Cenozoic sedimentary strata. Nine wells drilled along the northern coast of the Alaska Peninsula as well as several onshore Soviet wells in northeastern Siberia have direct significance to the submerged basins of the Bering Sea shelf. Although all of the wells on the Alaska Peninsula were abandoned as dry holes, significant shows of oil and gas were found. In addition, the USSR drilling resulted in the discovery of oil and gas in Miocene sandstone. Regional geologic and geophysical mapping suggests that there are suitable source beds, reservoir rocks, and traps within the basins beneath the Bering Sea shelf. However, it is not known if hydrocarbons are present or if the possible reservoirs are of commercial size. The major environmental hazards for petroleum exploration and development of the Bering Sea shelf include faulting and associated earthquakes, sea floormore » instability (slumping, erosion, etc.), volcanic activity in the southern shelf area, and seasonal ice flows (although the open southern shelf is virtually ice-free). There is significant fishing activity in the southern shelf region between the Alaska Peninsula and the Pribilof Islands and any development of the outer continental shelf should be compatible with this industry. (LTN)« less