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

Oil and Gas Development and Impacts
Exploratory Drilling
The purpose of exploratory drilling is to verify: 1) if the geological formations have accumulations
of hydrocarbons, and 2) if the site can produce enough oil and gas to make it economically
viable to proceed with further development.
There are a number of steps in a drilling program. These include drill site selection; drill site
preparation; rigging up; spudding in (i.e., drilling the well); and analysis of drilling data.
Drill Site Selection: Companies will choose a drilling site that allows them to easily (and cheaply)
access the target geological formations. Surface conditions may affect where drilling can
occur. Wells are usually drilled where there is a fairly level ground surface of sufficient size (several
acres, typically) to accommodate the drilling rig, reserve pits, and storage space for the
materials and equipment used during the drilling program.
Drill site selection can be an important issue for landowners. Landowners may not want to hear
or see the drilling operations, or live with the noise or pollution associated with the heavy equipment.
Also, the company’s preferred site may cause damage to important areas on a landowner’s
property, such as crops or ecologically sensitive areas. Some types of formations allow for
considerable flexibility in drill site location (e.g. coalbed methane) while others require more
precision to hit the resources (e.g. some tight sands).
You may want to get your own survey done. The company may be more receptive to your wishes
if you can demonstrate that your preferred access route or drill pad site is a technically sound
alternative to the company’s preferred location. See Alternative Technologies and Practices
later in this chapter for information on directional drilling.
Drill Site Preparation: Drill site or well pad preparation is when the most dramatic changes to
the surface are likely to occur. There may be a number of private contractors (or subcontractors)
on site during this period, and heavy equipment traffic tends to be intense during this
phase of development.
To start off, access roads have to be built. Thus, one is likely to see bulldozers, road graders and
gravel trucks in the early stages of drill site preparation. Once access is provided, the drill site will
be cleared of vegetation and leveled. A pad for the equipment may be built (often out of gravel)
if there is concern about ground instability or if the ground is subject to freeze/thaw cycles. 41
Pits may be constructed to contain water for drilling operations, to store drilling fluids, and to
dispose of drill cuttings and other wastes. If required by government regulations, some or all of
these pits will be lined with a clay or a synthetic liner. Alternatively, tanks may be brought onsite
to store products used during the drilling stage, as well as any waste created during drilling.
When this work has been completed, the drilling contractor will move in with all the equipment
required for the drilling of the well.
Rigging up: Rigging up includes erecting the drilling rig; installing equipment to supply electricity,
compressed air, and water; and setting up storage facilities.
Drilling rigs operate the hoist that raises and lowers the drill stem and bit. For shallow wells, the
drill rig may be self-contained on a single truck. Deep-well rigs, however, may have to be brought
to the site in several pieces and assembled at the site. The rig is located and leveled over the
main well hole, and all associated engines, pumps, and rotating and hoisting equipment are
connected or positioned close to the rig. Water and fuel tanks are filled, and additives for drilling
fluid are stored on location. Then, the drilling contractor is ready to begin drilling operations. 42
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