A specialized unit called a jackup rig, at left, drilled a natural gas well last year at Hilcorp’s Tyonek platform, right, in Cook Inlet. (Nathaniel Herz for Alaska Public Media) There are 17 offshore ...

Hilcorp’s Spurr platform, photographed last year, has not produced any oil or gas since 1992. (Nathaniel Herz for Alaska Public Media) The Spurr oil platform stopped pumping crude from beneath the ...

SPARTAN 151 RIG, COOK INLET — Deep below the ocean floor outside Anchorage this spring, a huge drill bit chewed through multi-million-year-old sandstone, sending crushed bits of rock back to the ...

The Spurr oil platform stopped pumping crude from beneath the silty ocean water outside Anchorage in 1992. The platform, built in Cook Inlet during Alaska’s first oil boom in the 1960s, was losing ...