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

STAGES OF OIL & GAS DEVELOPMENT
Surface and Other Disturbances—Tips for Landowners
• Revegetation of the pad surface and pipeline rights-of-way with native grasses is one of the
best methods for controlling the spread of noxious weeds. 73
• Lined pits or preferably tanks should be used to store spent mud, drill cuttings and solids,
water used to wash any machinery, and surface runoff from the drilling area. These waste
materials should be transported to a proper disposal site.
• Pitless or closed-loop drilling, which does not require pits for disposal of drilling wastes, is
an option that reduces the potential for soil and water contamination. More details on pitless
drilling are included in Alternative Technologies and Practices later in this chapter.
• Some traditional drilling fluid additives are toxic, but substitutes do exist: 1) replacement of
chrome lignosulfonate dispersants with chrome-free lignosulfonates and polysaccharide
polymers; 2) use of amines instead of pentachlorophenols and paraformaldehyde as biocides;
3) lubrication with mineral oil and lubra-beads instead of diesel oil. 74
• Instead of disposing of drilling fluids in pits on-site, companies can use filtration processes
to recondition the mud, so that it can be used for multiple wells before being discarded.
Other possible uses for used drilling fluids include using it to plug unproductive wells or to
spud in new wells. 75
2. FIELD ORGANIZATION
This stage is primarily administrative, and usually involves government regulators. The purpose
of field organization is to make the development of the oil or gas field more financially lucrative
by creating a system for efficiently extracting the oil and gas from a particular region or field.
Well spacing, pooling, and unitization are examples of organizational techniques that are
applied during this stage.
It is during this stage of development that many citizens become involved because the impacts
are broadly distributed over a geographic area (i.e., the oil or gas field), and governments often
provide the public with an opportunity to comment on how the development might occur.
Well Spacing
Through well testing and geologic analyses it is possible to estimate the volume of oil and gas
in a particular reservoir that can be drained by a single well, and then estimate how many wells
will be needed to drain all of the oil or gas from the reservoir. Using these types of calculations,
state governments determine how close together the wells need to be located (i.e., the well density)
to most efficiently and economically drain the reservoir. The state agencies then define the
number of wells that can be drilled in a specified surface area (usually per acre). The area allocated
by the state for the drilling of an oil or gas well is sometimes referred to as the drilling
unit.
Typically, states enact spacing laws on a state-wide basis. States may also adopt different rules
for particular fields.
• For example, in Colorado an operator can generally drill one well per 40 acres per formation
anywhere in the state, unless there is an existing field rule in place, like the Ignacio-
Blanco field rule in Southwestern Colorado. As of May, 2005, the Ignacio-Blanco field rule
allows only one well to be drilled into the Fruitland Formation per every 160 acres.
Spacing rules apply to geological formations. That means if there are two or more formations
that produce gas or oil in an area, then it is possible to end up with many more wells.
• For instance, in Southeast Colorado there are two major producing formations for coalbed
methane: the Vermejo and Raton formations. In that region, an operator is allowed to drill
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