Geology Reference
In-Depth Information
Average wells are at some 12,000 feet deep. As a result, temperatures and pres-
sures here are intense: the temperature at the bottom of the well averages 300
degrees Fahrenheit, and pressures at the wellhead exceed 10,000 pounds per
square inch.
Marcellus
: As noted earlier, this play is located in the Northeast, the biggest gas-
consuming region of the country, and was first developed in 2004. For now,
most of the Marcellus gas wells are in Pennsylvania, which has aggressively
promoted hydrofracking. The wells there average about 6,200 feet deep and
cost roughly $5 million each. By contrast, neighboring states have been more
cautious to exploit the Marcellus. New Jersey and New York have temporar-
ily banned hydrofracking, pending the results of lengthy environmental and
health reviews. The Marcellus is a natural gas shale stacked on top of another
major play, the Utica Shale, which contains oil (see below).
Monterey Shale
: Running southeast of San Francisco, this formation covers about
1,750 square miles, from southern to central California. The federal EIA es-
timates that it holds more than 15.4 billion barrels of oil in shale deposits that
are estimated to be 1,900 feet thick and lie at an average depth of 11,000 feet.
If the estimates prove accurate, that would mean the Monterey contains four
times as much tight oil as the Bakken Formation, and approximately 64 per-
cent of the nation's shale oil reserves. If exploited, the Monterey's tight oil
could yield 2.8 million jobs and $24.6 billion in state and local taxes, boost-
ing California's economy by 14 percent by 2020, according to a recent study
from the University of Southern California. But with complex geology that is
prone to earthquakes, disappointing early production numbers for wells, a lack
of water, and strong environmental opposition, widespread hydrofracking in
California is not a given. (This region has long been commercially exploited
by conventional oil drillers, and is the nation's third-highest oil producer, after
Texas and North Dakota.)
Niobrara
: This emerging oil and gas play lies near the Rocky Mountains beneath
northeastern Colorado, Wyoming, Nebraska, and Kansas. Made up of Creta-
ceous rock, the Niobrara deposit measures between 150 to 1,500 feet thick and
lies about 6,200 feet deep. Though exploitation is still in its early stages, the
Niobrara's brittle, calcareous chalk is well suited for hydrofracking, and it is
considered a potentially huge play. Most production is focused on the north-
eastern corner of Colorado, in the Denver-Julesburg basin.
