Shell encountered water saturated sand in its 2015 Burger well

During a talk to the Alaska Geological Society on Nov. 21 about new concepts for Chukchi Sea geology, Shell geologist Thomas Homza mentioned that Shell had encountered water, not oil, with its Chukchi Sea Burger J exploration well in 2015. Disappointing results from the Burger well were a prime factor in Shell’s subsequent departure from its Chukchi Sea exploration program.

Shell had been hoping for a major oil find in the Burger prospect, a huge geologic structure about 25 miles in diameter, 70 miles northwest of the Chukchi coastal village of Wainwright. From a previous well, the Burger No. 1 well, drilled in 1990, the prospect is known to hold a major pool of natural gas - Shell had hoped to find oil below the gas. The target potential hydrocarbon reservoir consisted of sands equivalent to sands in the Kuparuk River field in the central North Slope.

Apparently the Burger J penetrated the target horizons but found about 90 feet of high quality water saturated sandstones, with no oil shows. Homza said that data from sidewall cores indicated that the reservoir had once held an oil column, but that the oil had spilled out. Evidence suggests a complex history of filling and spilling of the reservoir, with the spillage possibly related to the collapse of a major regional geologic structure, Homza said.

Despite this disappointment, the Chukchi Sea region remains highly prospective for oil and gas. The complex geology of the region includes many rock horizons equivalent to those in the petroleum systems of the North Slope, including oil source rocks such as the prolific Shublik formation.

- ALAN BAILEY