AOGCC issues Northstar pool rules, injection order

Kristen Nelson

The Alaska Oil and Gas Conservation Commission has approved pool rules and an area injection order for BP Exploration (Alaska) Inc.’s Northstar field on the North Slope. The field is scheduled to come online before the end of the year.

Minimum well spacing within the Northstar oil pool will be 40 acres.

With the exception of the Class I disposal well, all wells are capable of unassisted flow of hydrocarbons to the service. The commission is requiring that each well, with the exception of the disposal well, must be equipped with a fail-safe automatic surface safety valve “capable of preventing an uncontrolled flow” and a fail-safe automatic surface controlled subsurface safety valve “capable of preventing an uncontrolled flow, unless another type of subsurface valve with that capability is approved by the Commission.”

In its area injection order the commission noted that enhanced oil recovery using miscible gas injected into the Sag River, Shublik and Ivishak formations “will preserve reservoir pressure energy and enhance ultimate recovery.” BP plans a miscible gas injection phase followed by lean chase gas injection for the remainder of the oil production phase of field life and has estimated that the miscible gas-lean gas chase injection will result in 29 percent increased recovery (82 million barrels) over primary production alone.

Total recovery from Northstar is estimated at 176 million barrels.