Exploration Strategies for the U.S. Rockies
Stephen A. Sonnenberg
Kerr-McGee, Denver, CO
Exploration for oil and gas in the U.S. Rockies is a critical component of meeting the rising demand for oil and gas. Resource assessments from various groups suggest abundant remaining resources in the Rockies.
During the 1990s, restructuring of the industry and a move towards low
risk development
drilling took place. Currently, several resource play areas are
being developed that were the result of exploration in the 1970s and 1980s.
Exploration is a critical aspect of finding new resource plays.
The Mesozoic
of the Western Interior contains significant potential for
several reasons. The
Mesozoic
section contains tremendous volumes of mature
source
rocks
(organic rich shales and bedded coals) and reservoir
rocks
. Several
transgressive-regressive (T-R) cycles create the potential for large
conventional
and
unconventional
traps (resource plays). Superimposed on these
T-R cycles is the Laramide event which broke the Western Interior basin in the
U.S. into many
basins
along with burying
source
and reservoir
rocks
. The burial
in many cases caused significant degradation in reservoir quality (i.e. tight
gas), matured the
source
rocks
and created abnormally pressured systems. Tight
reservoirs
, shale, and coals are considered
unconventional
reservoirs
and should
be a focus of future exploration.
Exploration strategies should include the following: identification of potential basin center areas, analyses of geothermal gradients (most fields are associated with geothermal anomalies), abnormal pressure identification, visualization techniques, specialized maps, application of new technologies, and a study of commercial and minor or noncommercial occurrences of oil and gas.
AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005