Oil and Gas Exploration Impacts
Potential environmental impacts from exploration activities (including seismic surveys and exploratory drilling) are generally temporary and of relatively small magnitude.
Activities during the exploration phase (including seismic surveys, testing, and exploratory drilling) are temporary and are conducted at a smaller scale than those at the drilling/development, production, and decommissioning/reclamation phases. The impacts described for each resource would occur from typical exploration activities, such as localized ground clearing, vehicular traffic, seismic testing, positioning of equipment, and exploratory drilling. Most impacts during the exploration phase would be associated with the development of access roads and exploratory wells. Impacts to resources would be similar in character, but lesser in magnitude, to those for the drilling/development phase. Potential impacts from these activities are presented below, by the type of affected resource.
Primary sources of noise associated with exploration include earth-moving equipment, vehicle traffic, seismic surveys, blasting, and drill rig operations.
Impacts on air quality during exploration activities would include emissions and dust from earth-moving equipment, vehicles, seismic surveys, well completion and testing, and drill rig exhaust. Pollutants would include particulates, oxides of nitrogen, carbon monoxide, sulfur dioxide, and volatile organic compounds (VOCs). Nitrogen oxides and VOCs may combine to form ground-level ozone. Impacts would depend upon the amount, duration, location, and characteristics of the emissions and the meteorological conditions (e.g., wind speed and direction, precipitation, and relative humidity). Emissions during this phase would not have a measurable impact on climate change.
The amount of surface and subsurface disturbance is minimal during the exploration phase. Cultural resources buried below the surface are unlikely to be affected; while material present on the surface could be disturbed by vehicular traffic, ground clearing, and pedestrian activity (including collection of artifacts). Exploration activities could affect areas of interest to Native Americans depending on the placement of equipment and/or level of visual intrusion.
Surveys conducted during this phase to evaluate the presence and/or significance of cultural resources in the area would assist developers in siting project facilities in order to avoid or minimize impacts to these resources.
Impacts to ecological resources (vegetation, wildlife, aquatic biota, special status species, and their habitats) would be minimal and localized during exploration because of the limited nature of the activities. The introduction or spread of some nonnative invasive vegetation could occur as a result of vehicular traffic, but this would be relatively limited in extent. Seismic surveys could disturb wildlife. Exploratory well establishment would destroy vegetation and impact wildlife.
Surveys conducted during this phase to evaluate the presence and/or significance of ecological resources in the area would assist developers in siting project facilities in order to avoid or minimize impacts to these resources.
Exploration activities are limited and would not result in significant adverse impacts in any resource area; therefore, environmental justice is not expected to be an issue during this phase.
Hazardous Materials and Waste Management
Seismic and exploratory well crews may generate waste (plastic, paper, containers, fuel leaks/spills, food and human waste). Wastes produced by exploratory drilling would be similar, but occur to a lesser extent than those produced during drilling and operation of production wells. They would include drilling fluid and muds, used oil and filters, spilled fuel, drill cuttings, spent and unused solvents, scrap metal, solid waste, and garbage.
Health and Safety
The potential impacts on human health and safety resulting from exploration activities could include: occupational accidents and injuries; , vehicle or aircraft accidents, exposure to weather extremes, wildlife encounters, trips and falls on uneven terrain, adverse health effects from dust generation and emissions, and contact with hazardous materials (e.g., from spills). The potential for these impacts to occur would be low because of the limited range of activities and number of workers required during exploration.
Temporary and localized impacts to land use would result from exploration activities. These activities could create a temporary disturbance in the immediate vicinity of a surveying or monitoring site or an exploratory well (e.g., disturb recreational activities or livestock grazing). Wire pin flags used for surveying could be shredded in the making of hay. The leftover metal bits can kill livestock that eat the feed. Livestock and wildlife can also die after eating ribbons attached to the flags. Exploration activities are unlikely to affect mining activities, military operations, or aviation.
Paleontological resources are nonrenewable resources. Disturbance to such resources, whether it is through mechanical surface disturbance, erosion, or paleontological excavation, irrevocably alters or destroys them. Direct impacts to paleontological resources would include surface disturbance during seismic surveys and the drilling of exploratory wells and the construction of access roads and other ancillary facilities. The amount of subsurface disturbance is minimal during the exploration phase and paleontological resources buried below the surface are unlikely to be affected. Fossil material present on the surface could be disturbed by vehicular traffic, ground clearing, and pedestrian activities (including collection of fossils).
Surveys conducted during this phase to evaluate the presence and/or significance of paleontological resources in the area would assist developers in siting project facilities in order to avoid or minimize impacts to these resources.
As the activities conducted during the exploration phase are temporary and limited in scope, they would not result in significant socioeconomic impacts on employment, local services, or property values.
Soils and Geologic Resources
Surface effects from vehicular traffic could occur in areas that contain special (e.g., cryptobiotic) soils. The loss of biological crusts can substantially increase water and wind erosion. Also, soil compaction due to development activities at the exploratory well pads and along access roads would reduce aeration, permeability, and water-holding capacity of the soils and cause an increase in surface runoff, potentially causing increased sheet, rill, and gully erosion. The excavation and reapplication of surface soils could cause the mixing of shallow soil horizons, resulting in a blending of soil characteristics and types. This blending would modify physical characteristics of the soils including structure, texture, and rock content, which could lead to reduced permeability and increased runoff from these areas. Potential impacts to geologic and mineral resources would include depletion of hydrocarbons and sand and gravel resources. It is unlikely that exploration activities would activate geologic hazards. Impacts to soils and geologic resources would be proportional to the amount of disturbance. The amount of surface disturbance and use of geologic materials during exploration would be minimal.
No impacts on transportation are anticipated during the exploration phase. Transportation activities would be temporary and intermittent and limited to low volumes of light utility trucks and personal vehicles.
Impacts to visual resources would be considered adverse if the landscape were substantially degraded or modified. Exploration activities would have only temporary and minor visual effects, resulting from the presence of drill rigs, workers, vehicles, and other equipment.
Water Resources (Surface Water and Groundwater)
Minimal impact to water resources (water quality, water flows, and surface water/groundwater interactions) would be anticipated from exploration activities. Exploratory wellbores may provide a path for surface contaminants to come into contact with groundwater or for waters from subsurface formations to commingle. They may also decrease pressure in water wells and affect their quality. Very little produced water would likely be generated during the exploration phase. Most water needed to support drilling operations could be trucked in from off-site.