Oil Exploration in Pine Valley, Nevada

Cheryl H. Scott, Alan K. Chamberlain

Three oil fields have already been established in Pine Valley, which is located in north-central Nevada along the late Mesozoic thrust trend. The potential exists for much more future exploration because of excellent reservoir potential, favorable hydrocarbon generating system, and trapping mechanisms.

The Devonian is one of the main target reservoirs of Pine Valley. Pine Valley lies near the Devonian shelf edge, and carbonate facies from that period undergo abrupt changes in the Pine Valley region. The Guilmette/Devil's Gate apparently develops into a reefal system along the Uinta-Cortez arch in this area. Fore-reef and basinal facies are found at Cortez Mountain on the west side of Pine Valley. Mississippian sandstones and Tertiary tuffs are two other reservoirs which produce oil.

At Blackburn field, upper plate rocks are overmature. Produced oil has been identified as Mississippian. Regional studies show Mississippian source rocks of Pine Valley to be slightly immature to mature oil in the lower plate. Gravity of the oil is approximately 26-30° API. Oil from the Tomara Ranch and North Willow Creek fields is most probably also from the Mississippian. Its API gravity is similar to the oil produced from Blackburn field.

Blackburn field is a Tertiary trap probably generated by shear faulting. Tertiary traps throughout Nevada, including Blackburn, are generally small and hydrocarbon potential is limited. Larger traps associated with the late Mesozoic compressional event have much more potential and hold hundreds of millions of barrels of oil.

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