Surface Expression of Subsurface Structure at Ninilchik Field, Kenai Peninsula, Alaska

By

D.B. Buthman and L.J. Smith (Unocal Alaska Resources)

The surface expression of subsurface structure at Ninilchik Anticline—a large area of closure mapped with seismic, well, and gravity data—was investigated during the summer months of 2000 and 2001. Critical south dip reversal that defines the anticline is obvious in Sterling sandstone beds in the bluffs located just north of the Ninilchik River mouth. Between the Ninilchik Townsite and the Clam Gulch Recreation area, the surface expressions of four normal faults are positively identified, mapped, and correlated with seismic profiles. Two of the faults occur in the south Ninilchik area, one occurs north of the Grassim Oskolkoff #1 well, and one lies just north of the Falls Creek #1 well. The strike and dip of three of these faults were measured, as were 65 bedding strike and dips. Natural gas seeps are documented on the south end of the structure.

AAPG Search and Discovery Article #90008©2002 AAPG Pacific Section/SPE Western Region Joint Conference of Geoscientists and Petroleum Engineers, Anchorage, Alaska, May 18–23, 2002.