Oil and Gas at Your Door? (2005 Edition) - Earthworks

STAGES OF OIL & GAS DEVELOPMENT
The drilling of a directional well is more costly than drilling a typical vertical well because
it requires specialized equipment; constant attention to the placement of the drill bit; it
takes several days longer to drill the wells; and pumping costs may increase because
parts may wear out faster. According to the U.S. EPA, however, the increased costs of directional
drilling are often more than offset by increased production and the reduced need
for drilling multiple wells. 341
In the Dundee Formation of Michigan, as much as 85 % of the known oil remained in
the formation after many years of production, but many wells were on the verge of
being plugged because daily production had fallen to only five barrels of oil per well.
The U.S. Department of Energy co-sponsored a project to drill a horizontal well in the
formation. This well produced 100 barrels per day. The program attracted other well
developers, and 20 to 30 additional horizontal wells are being drilled in the formation.
It is estimated that the application of horizontal drilling to this formation may yield an
additional 80 to 100 million barrels of oil. 342
4. Flareless or “green” completions reduce flaring and venting of natural gas. Before natural
gas and coalbed methane wells begin producing gas for sale, the well bore and surrounding
reservoir must be “cleaned up” (i.e., any fluids, sand, coal particles, or drill cuttings
within the well bore must be removed). The conventional method for doing this is to
pump air down the well bore, which lifts the waste fluids and solids out. The solid and liquid
waste materials are then dumped into a pit or tank, and any gas that is removed is
flared or vented to the atmosphere. In some flareless or green completions, natural gas,
rather than air, is pumped down the well bore to clean it out. 343
In flareless or green completions the gas that comes to the surface is separated from fluids
and solids using a series of heavy-duty separators (sometimes referred to as “flowback
units”). The water is discharged to tanks to be reused, the sand is sent to a reserve pit,
and the gas is either cycled back through the well bore, or sent to a pipeline to be sold
rather than vented or flared. According to the U.S. Environmental Protection Agency (EPA),
benefits of this system include: the elimination or reduction in venting or flaring of natural
gas; sale of the gas and condensate provides the operator with an immediate revenue
stream; there is a reduction in solid waste and water pollution; and the system enables
safer operating practices.
Emissions Reductions: One company, which drilled
63 wells using flareless completions, reported a
reduction in natural gas emissions of 7,410 thousand
cubic feet per year, which is 70% of the gas that
would formerly have been vented to the atmosphere.
344 Another company has been able to reduce
flaring by 85-90%. 345
Costs and Pay-Back: The capital costs for companies
include the use of separators, sand traps and tanks.
One company reported these costs as being
$180,000. The equipment, however, can be moved
from site to site, so if a company were to complete 60
wells per year the annual capital charges would be
less than $10,000. Operating costs are less than
$1,000 per year. EPA has estimated that “green completions”
can pay back their costs in about 1 year.
FIGURE I-39. TYPICAL COMPLETION WITH A FLARE BERM AND
WASTE PITS. Photo by Dan Randolph
An alternative to sending the gas to the pipeline is to send it to a flare tank. Flare tanks
I-67