What’s new in exploration

	Vol. 232 No. 6
NINA M. RACH, CONTRIBUTING EDITOR

Frontier exploration in the Kara Sea

More than 400 years ago, in 1594 and 1595, Dutch explorer Jan Huyghen van Linschoten sailed with the Dutch navigator William Barents to search for a maritime route along the northern coast of the Eurasian landmass to the Orient via the Arctic—the Northeast Passage. Both voyages ended icebound in the Kara Sea, but Linschoten survived to publish his account of the journeys in 1601.
 
Because of its remoteness and challenging environmental conditions, the Arctic shelf has been among the last frontier provinces for oil and gas exploration. Following some exploration success in the Beaufort Sea, the focus in Eurasia is on the Barents Sea, the primary site of current Soviet efforts to develop Arctic resources that began with an oil discovery on Kolguyev Island.

The Kara Sea is a new target, north of the prolific West Siberian basin and east of the Barents Sea. The sea has an area of 340,000 sq mi (880,000 sq km). Average depth is 417 ft (127 m) and maximum depth is 2,034 ft (620 m).

Logistics. Exploring on the Arctic continental shelf is necessarily a long-term proposition, because of the need to develop a support infrastructure for operations in remote areas and the limited ice-free time window. Severe environmental conditions and remote location make it a costly place to do business, yet the rewards may be great. There are few ports to serve as supply bases. The closest major port is Murmansk, but using this for Kara Sea operations is akin to using Quebec as a base of operations for Beaufort Sea operations.

Source rocks. As early as 1988, researchers at the US Central Intelligence Agency penned a document, “The Kara Sea: A Soviet oil resource for the turn of the century,” which assessed the petroleum potential of the Kara Sea. Researchers concluded that the oil potential of the Kara Sea was only surpassed by that of the Barents Sea and perhaps the Caspian region. If developed, they wrote, the Kara Sea could supply about one-sixth of Soviet demand. The authors estimated that there was a small chance that recoverable oil resources in the Kara Sea could equal proved reserves in Alaska’s Prudhoe Bay, an excellent chance that they were equivalent to proved reserves in Libya, and an outside chance that they could match North Sea reserves.

Source rocks in the northern Kara are similar in age and type to those in the Barents Sea, and the source rocks in the southern Kara are similar to those in the West Siberian basin. Two major source rocks are thought to occur in the northern Kara: Upper Devonian shales (as in the Barents Sea and Pechora basin) and Upper Jurassic shales and limestones. A third potential source rock in the northern Kara Sea is Upper Cretaceous. There is a buried sill between the northern and southern Kara Sea, which may be a significant structural trap.

Seismic surveys. The Arctic Refraction Catalogue, maintained by Natural Resources Canada, includes seven profiles collected in the Barents and Kara Seas, totaling 2,350 km. The refraction profiles are useful for defining features from the seabed to the crust-mantle boundary. Russia’s State Scientific Centre Yuzhmorgeologiya, based in Gelendzhik, shot a high-resolution survey over Obskaya Guba (the Gulf of Ob) in the Kara Sea, using air guns and telemetry systems to target the Paleozoic sediments.

Russia-Scandinavia joint exploration. The international Arctic Coastal Dynamics (ACD) project is one of the few international joint ventures involving Russia and Scandinavian countries. It includes two key sites in the southwestern Kara Sea: the Shpindler site (Yugorsky Peninsula, 80 km east of the Amderma settlement) and the Mare-Sale site (western coast of the Yamal Peninsula). Researchers at the Institute for Geology and Mineral Resources of the Ocean (VNIIOkeangeologia; en.vniio.ru) in St. Petersburg shot high-resolution seismic over these two sites using a towed “Sonic-3” system consisting of high- and low-frequency side-scan sonar (30 kHz and 100 kHz, respectively) and a 4–8-kHz seismic chirp-type profiler with impulse power of up to 2.5 kW. They reported that the southern Kara Sea shoal has a smooth, gently dipping surface with water depths to 30–40 m, evidence of submarine permafrost and relict thermocirques located along surface fault lines.

Joint venture with IOCs. Exploring for and developing resources in the Kara Sea will require large capital outlay and foreign technology and expertise, such as that developed by various operators in the Alaskan and Canadian portions of the Beaufort Sea.

Russia’s state-controlled oil giant Rosneft and British Petroleum have estimated the cost of  shooting seismic surveys and drilling six wells on the Kara Sea shelf at $1 billion. In January, BP signed an agreement with Rosneft on a $16 billion cross-share holding as part of a global strategic alliance. The companies agreed to develop three blocks in Russia’s Arctic Ocean, known as East Prinovozemelsk-1, -2 and -3, with reserves estimated at 5 billion tonnes of oil and 350 Tcf of gas.

The two companies, facing unprecedented technical challenges, had agreed to form a joint center on Arctic technologies in St. Petersburg, to collaborate with leading Russian and foreign research institutes in the development of new methods and tools for exploring the Arctic. In late May, the deal collapsed after BP could not finalize an agreement to buy out its current Russian partners. BP may renegotiate a different partnership with Rosneft, or other international oil companies, such as Shell, could enter the picture.