Oil Fields of Northern Railroad Valley, Nye County, Nevada

Herbert D. Duey

Since 1954 four oil fields have been discovered in northern Railroad Valley: Eagle Springs, Trap Springs, Currant, and Kate Spring. Though similar in many aspects, each is unique in structure, stratigraphy, and reservoir conditions.

Oil accumulation in all four fields is related to faulting, and all reservoirs are either fractured or enhanced by fractures. The reservoir rocks vary from Tertiary ignimbrites to Tertiary lacustrine sediments to Paleozoic carbonates. A Tertiary unconformity controls the seal at Trap Spring, Eagle Springs, and Kate Spring. At Currant the seal is the Tertiary Sheep Pass shale.

There are two basic oil types. Oil has been generated from shales of the Tertiary Sheep Pass Formation and the Mississippian Chainman Formation. Oil generation is probably recent and continuing. These oils are mixed in at least two reservoirs.

Over 10 million bbl of oil have been produced in northern Railroad Valley, and despite the variability of the stratigraphy, structure, and oil generation, the area is still a viable hunting ground for modest reserves. Using these fields along with their permutations and combinations as models makes exploration in the rest of the Basin and Range province inspiring.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.