Iraqi Kurdistan All in the Timing

Mature Fields
Rangely
Teamwork at
Colorado’s
THOMAS SMITH
Rangely
oil field, with over 900
MMb of oil produced,
has been viable and
economic for more than
seven decades thanks
to an innovative and
flexible approach.
One of the oldest and largest conventional
oil fields in the US Rocky
Mountain region, Rangely is in a remote
north-west corner of Colorado along the
White River. This area was originally
referred to as Raven Park in the early
1870s by C. A. White, a geologist with
the Hayden Survey. The upper portion
of the White River valley was formed
by erosion of the relatively soft Upper
Cretaceous Mancos Shale on the crest
of a large anticlinal structure. The
discovery of an oil seep in a spring
along the north bank of the White
River brought attention to the area
as a potential oil field and a number
of companies were organised among
the local residents to prospect and
develop it. Drilling started in 1901 with
oil discovered in the Mancos Shale at
depths of 150 to 520m. By 1903, 13
different companies had drilled the
The Rangely oil field is located along the
eastern edge of the Uinta Basin in northeastern
Colorado, about 270 km east of Salt
Lake City, Utah.
A display, at its original well
head site of the Raven A-1
replica pumping unit that
discovered the deep Weber
Sand Unit in 1933. The photo,
taken in the spring of 2013,
shows a workover rig in the
background. The discovery
well display was moved to
the Rangely Museum in the
spring of 2015 to make room
for field operations.
Thomas Smith
Chevron
74 GEOExPro November 2015