Fault
Seals in Oil Fields in Nevada
Norman H. Foster, Harry K. Veal, Louis C. Bortz
Faults form seals for oil accumulations in the Eagle Springs, Trap
Spring,
and Blackburn fields, and probably in the Grant Canyon field, in Nevada. The
main boundary
fault
on the east side of the Pine Valley graben forms a seal in
the Blackburn field. A
fault
on the west side of the
Trap
Spring field forms a
seal. In Grant Canyon field, it is interpreted that the main boundary
fault
on
the east side of the Railroad Valley graben forms a seal.
Calcite is deposited by hot spring activity, plugging up many fault
zones
and, in some cases, forming seals. Some
fault
zones have calcite mineralization
up to several thousand feet wide. Within the Eagle Springs field on the east
side of the Railroad Valley graben, a northeast-trending
fault
separates oil
accumulations with different oil-water contacts. This separation indicates that
the
fault
forms at least a partial seal within the accumulation.
AAPG Search and Discovery Article #91040©1987 AAPG Rocky Mountain Section Meeting, Boise, Idaho, September 13-16, 1987.