Print this pagePinedale 
Field
: a Giant New Gas Resource, Green River Basin,
Wyoming, U.S.A
The Pinedale Field is developing into one of the largest gas
fields in the Greater Green River Basin of southwest Wyoming and along with
Jonah Field, a significant new natural gas resource in America. Production is
from over-pressured, tight-gas sandstones of the Upper Cretaceous Lance
Formation and upper part of the undifferentiated Mesaverde
(“Lance Pool”), coincident with the Pinedale Anticline. Current development
along the Pinedale Anticline spans an area over 3 miles in width and 30 miles
in length. The gross hydrocarbon-bearing column, which exceeds 5,000 feet in
total thickness, consists mainly of fluvial and flood plain facies
rocks deposited in a broad alluvial valley. In order to better understand the
Lance Pool reservoir characteristics and to optimize the development of the
Pinedale Field, Ultra Petroleum Corp embarked on a coring program in which 10
wells were cored and a total of 853 feet of Lance Pool rock was recovered.
Detailed analysis of the core integrated with Ultra's geological, petrophysical
and geophysical models has led to a unique
understanding of the Lance Pool. The alluvial sandstones of the Lance Pool were
deposited in a rapidly subsiding basin by modest-sized rivers reflecting
constant channel-belt migration. The resulting reservoirs are laterally- and
vertically-discontinuous, multi-story sandstones. Effective reservoir
characteristics appear to include lower porosities and permeabilities,
a greater range of effective water saturations and a thicker net pay section
than previously believed.