The Northstar oilfield is located six miles off of the Beaufort Sea coast, and 11 miles northwest of Prudhoe Bay. Oil was originally discovered in the Northstar Unit by Shell in 1983 with exploration wells drilled from Seal Island. This manmade gravel island was built in 1982 in 37-feet of water. It was later abandoned by Amerada Hess in 1994. BP acquired most of the Northstar Unit leases in 1995 and developed the field.
Today, BPXA operates a 10-inch oil pipeline and a 10-inch gas pipeline that extend into the
Beaufort Sea to the gravel island, sometimes referred to as Northstar Island or Seal Island
(see photo above).
Produced crude oil is processed on Northstar Island and shipped via a trenched 10-inch oil
pipeline to the shore, crossing at Point Storkersen. The crude then travels 11 miles overland to TAPS Pump Station 1. Natural gas is transported from the Prudhoe Bay central compressor plant for 16 miles to Northstar Island in a second 10-inch pipeline that shares VSMs and a subsea trench with the oil pipeline.
The trenched pipes are designed and constructed to withstand potential seabed ice gouge and
settlement loading conditions of thawed soils. The subsea section of the pipelines employs a
leak detection system called LEOS, which is designed to sense hydrocarbon vapors surrounding the pipelines. This equipment is in addition to the oil pipeline's standard leak detection system, which monitors pressure, volume, and temperatures to detect releases.