Alaska probes oil spill at Conoco's Alpine field

ANCHORAGE, Alaska, May 21 (Reuters) - State regulators are investigating a small oil pipeline leak at ConocoPhillips' (COP.N: Quote, Profile, Research, Stock Buzz) Alpine field last weekend that was caused by corrosion on the line.

The incident, which resulted in a spill of 170 gallons (644 liters) of oil, comes two years after severe pipeline corrosion at BP's (BP.L: Quote, Profile, Research, Stock Buzz) Prudhoe Bay oil field led to the biggest spill on record on Alaska's North Slope.

The Alaska Department of Environmental Conservation said the leak at Conoco's Alpine field came out of a pinhole-sized hole in a low pressure pipeline, and was a surprise because the field is relatively new.

"In the old fields, we've been looking at corrosion for a lot of years," said Ed Meggert, on-scene coordinator for the Department of Environmental Conservation. "But this (field) is about eight years old."

Meggert said one theory about the corrosion is that it was caused by water settling in low parts of the line, as the pinhole was detected in one of the low spots, he said.

ConocoPhillips has placed a sleeve on the affected section of pipeline, and production from the field has not been significantly affected, he said.

ConocoPhillips has also launched an investigation of the incident, Meggert said. A company official was not immediately available for comment. (Reporting by Yereth Rosen; Editing by Marguerita Choy)