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Rotational model spins out clues to next
big Arctic oil find In search of the next Prudhoe: Shared geology indicates Alaska, Siberia and Canadian Arctic islands once were part of the same landmass Steve Sutherlin PNA Managing Editor
It may be that the North Slope has more in common with Siberia than Canada’s Arctic, geologically speaking — in which case, you can blame it on the rotational model.
And the model is more than just an esoteric talking point. It may actually hold the clues to where the next big Arctic oilfield is hidden, Mike Mickey, a paleontologist with Micropaleo Consultants Inc., told PNA in a recent interview.
Mickey, Alan P. Byrnes of the Kansas Geological Survey and Hideyo Haga of Micropaleo Consultants are co-authors of the soon-to-be published study, “Biostratigraphic Evidence for ‘Rotational’ Episodic Time-Transgressive Opening of the Canada Basin.”
The theory holds that the northern shores of Alaska and Siberia once touched Canada’s Arctic islands but, more than 200 million years ago, rotated counterclockwise into their current positions and resulted in formation of the Arctic Ocean basin. Mickey said there may actually be stronger geological links between the Siberian shelf and the North Slope than between the North Slope and Canada, although no drilling has yet been done offshore in the Siberian Arctic.
Mickey said BLM geologist Art Banet has studied geochemical fingerprints of oil and found that oil from fields on Alaska’s North Slope is exactly the same as oil from fields in the Canadian Arctic islands, suggesting oil in the two regions came from the same source. Prudhoe strike sparks Canadian interest Just after the discovery of oil at Prudhoe Bay, rotation theorists fanned hopes that Canada’s Arctic might hold a mammoth sister oilfield to Prudhoe Bay, North Slope geologist Gil Mull told PNA recently.
After ARCO and Humble Oil’s Prudhoe Bay No. 1 well struck oil at Prudhoe Bay, Mull was a well site geologist for Humble, which was part of Standard Oil of New Jersey, and a forerunner of Exxon. Mull and other Humble geologists were sent to the Edmonton exploration office of Imperial Oil, a 70 percent-owned subsidiary of Standard, to discuss the Alaska find and its possible implications for the Canadian Arctic. (Today, Exxon holds a 69 percent stake in Imperial. Both are major players in the Mackenzie Delta.)
“The Canadians were interested in the details of the geology in the Prudhoe Bay area,” Mull said. “They wanted to exchange information to see if there was anything similar along the margin of the Canadian Arctic islands.”
Mull said that the rotational theory is a hypothesis originally proposed by Irv Tailleur of the U.S. Geological Survey and endorsed by many, but not all geologists, because the evidence is not conclusive.
Not a lot is known about the geology offshore from the Canadian Arctic islands but Mull said that probably 80 percent to 90 percent of geologists familiar with the Arctic accept the idea that there has been some sort of rotation. Equal opportunity oil prospects Mickey said the Arctic islands and Siberia harbor equal opportunities to find oil.
“We know there’s oil in the Arctic islands already but it’s not economic to produce,” he said.
Far northeast Siberia may be the most likely to hold a Barrow or Prudhoe type formation, Mickey said. Because the Siberian-Alaska platform drifted away from the Arctic islands, the islands don’t have a subduction zone, such as the one that created the Colville trough in Alaska where the advancing crustal plate collides and descends under the Brooks Range.
“Alaska has more oil because of the subduction zone; that could be the case in Russia,” Mickey said. Some of Alaska’s oil exists in grabens, trenches that form when blocks of crust move downward between parallel faults near rifted plate margins, he said. BP targeted grabens at Milne BP understood grabens at Milne Point, and it increased production by targeting the graben system with its wells, Mickey said.
Proprietary seismic data and previously published studies confirm that the Niakuk No.1, Point McIntyre No. 1 and the Point Thomson wells penetrate grabens, according to a report provided to PNA by Mickey (see sidebar).
Russia is likely to have similar formations and similarities may exist between the National Petroleum Reserve-Alaska and eastern Siberia, Mickey said.
He believes that if oil formations similar to those on the North Slope exist in Siberia, they exist offshore.
The Siberian continental shelf is covered with younger sediments and is much wider than the continental shelf off the coast of Alaska. The positive match of Siberian oil to the Arctic islands awaits oil drilling on the Siberian shelf.
The Russians have little drill data, but there is great scientific interest on the part of the government, Mickey said: “The Russians have more people on these sorts of studies.” He visited Russia and found that paleontologists and geologists were interested in the rotational model.
But the Siberian shelf won’t be drilled any time soon because the Russian government doesn’t have the money or equipment needed, and it is unwilling to allow outsiders into the area for exploration, he said, adding that the Russians have plenty of oil onshore. Back to the Chukchi The best current prospect is probably to find and identify grabens in Alaska, Mickey said.
“There is more oil to be found in offshore northern Alaska in different age grabens,” he said.
Mickey predicts rigs will go back to the Chukchi Sea, this time with the right philosophy, to look for grabens and to look for stratigraphic traps holding oil along the ridges, applying lessons learned in Alaska.
Ice and a thick sediment layer, particularly in the Chukchi Sea and Siberia, will make drilling a challenge, Mickey said, but time, technology and higher oil prices will eventually conquer the obstacles.
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