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Tribal Energy and Environmental Information Clearinghouse: Environmental resources for tribal energy development
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Oil and Gas Production Phase Impacts

Environmental impacts that could occur during the production phase would mostly occur from long-term habitat change within the oil or gas field, production activities (including facility component maintenance or replacement), waste management (e.g., produced water), noise (e.g., from well operations, compressor or pump stations, and vehicles and equipment), the presence of workers, and potential spills.

Typical activities during the production phase include: operation of wells and compressor stations or pump stations, waste management, and maintenance and replacement of facility components. Potential impacts from these activities are presented below, by the type of affected resource.

Acoustics (Noise)

The main sources of noise during the production phase would include compressor and pumping stations, producing wells (including occasional flaring), and vehicle traffic. Compressor stations produce noise levels between 64 and 86 dBA at the station to between 58 and 75 dBA at about 1 mile (1.6 kilometers) from the station. Use of remote telemetry equipment would reduce daily traffic and associated noise levels within the oil and gas field area. The primary impacts from noise would be localized disturbance to wildlife, recreationists, and residents. Noise associated with cavitation is a major concern for landowners, livestock, and wildlife.

Air Quality

The primary emission sources during the production phase would include compressor and pumping station operations, vehicle traffic, production well operations, separation of oil and gas phases, and on-site storage of oil. Emissions would include volatile organic compound (VOCs), nitrogen oxides, sulfur dioxide, carbon monoxide, benzene, toluene, ethylbenzene, xylenes, polycyclic aromatic hydrocarbons (PAHs), hydrogen sulfide, particulates, ozone, and methane. Venting or flaring of natural gas (methane) may occur during oil production, well testing, oil and gas processing, cavitation, well leaks, and pipeline maintenance operations. Methane is a major greenhouse gas. Compounds such as carbon dioxide and hydrogen sulfide may seep following coal bed methane development. Air pollution oil and gas production may cause health effects and reduce visibility. Coal bed methane production may contribute to reducing the threat of global climate change. Methane is one of the most important greenhouse gases, so utilizing the coal bed methane would decline the venting of this gas during coal mining. About 4% of methane released to the environment is from conventional oil and gas wells and 6% is from coal mining.

About 100 tons of coal is brought to the surface during the cavitation process to increase coal bed methane flow. It is usually burned on site, which can last for up to 10 days. This can release nitrogen oxides, carbon dioxide, sulfur dioxide, lead, and mercury.

Cultural Resources

During the production phase, impacts to cultural resources could primarily occur from unauthorized collection of artifacts and from visual impacts. In the later case, the presence of the aboveground structures could impact cultural resources with an associated landscape component that contributes to their significance, such as a sacred landscape or historic trail. Damage to localities caused through off-highway vehicle (OHV) use could also occur. The potential for indirect impacts (e.g., vandalism and unauthorized collecting) would be greater during the production phase compared to the drilling/development phase, due to the longer duration of the production phase.

Ecological Resources

During the production phase, adverse impacts to ecological resources could occur from:

  1. Disturbance of wildlife from noise and human activity;
  2. Exposure of biota to contaminants; and
  3. Mortality of biota from colliding with aboveground facilities or vehicles.

Ecological resources may continue to be affected by the reduction in habitat quality associated with habitat fragmentation due to the presence of production wells, ancillary facilities, and access roads. In addition, the presence of access roads may increase human use of surrounding areas, which in turn could impact ecological resources in the surrounding areas through:

  1. Introduction and spread of invasive nonnative vegetation,
  2. Fragmentation of habitat,
  3. Disturbance of biota,
  4. Increase in hunting (including poaching), and
  5. Increased potential for fire.
The presence of an oil or gas field could also interfere with migratory and other behaviors of some wildlife.

Discharge of produced water inappropriately onto soil or into surface water bodies can result in salinity levels too high to sustain plant growth. One notable impact to wildlife is the potential for contact with petroleum-based products and other contaminants in reserve pits and water management facilities. Wildlife can become entrapped in the oil and drown, ingest toxic quantities of oil by preening (birds) or licking their fur (mammals); or succumb to cold stress if the oil damages the insulation provided by feathers or fur. Hypersaline water in evaporation ponds can also cause sodium toxicity.

In locations where naturally occurring radioactive material (NORM)-bearing produced water and solid wastes are generated, mismanagement of these wastes can result in radiological contamination of soils or surface water bodies.

In some coal bed methane production areas, methane gas could seep up into fields and create dead zones where methane-saturated soils could starve roots of vegetation. High levels of methane could asphyxiate wildlife in their burrows.

Environmental Justice

Possible environmental justice impacts during the production phase include the alteration of scenic quality in areas of traditional or cultural significance to minority populations. Noise and health and safety impacts are also potential sources of disproportionate effects to minority or low-income populations.

Hazardous Materials and Waste Management

Industrial wastes are generated during routine operations (lubricating oils, hydraulic fluids, coolants, solvents, and cleaning agents). These wastes are typically placed in containers, characterized and labeled, possibly stored briefly, and transported by a licensed hauler to an appropriate permitted off-site disposal facility as a standard practice. Impacts could result if these wastes were not properly handled and were released to the environment. Environmental contamination could occur from accidental spills of herbicides or, more significantly, oil. Chemicals in open pits used to store wastes may pose a threat to wildlife and livestock.

"Fraccing" fluids can contain potentially toxic substances such as diesel fuel (which contains benzene, ethylbenzene, toluene, xylenes, naphthalene, and other chemicals), PAHs, methanol, formaldehyde, ethylene glycol, glycol ethers, hydrochloric acid, and sodium hydroxide.

Sand separated from produced water must be disposed of properly, and it is often contaminated with oil, trace amounts of metals, or other naturally occurring constituents.

During the production phase, large volumes of scale and sludge wastes can accumulate inside pipelines and storage vessels. These wastes consist of precipitated sulfate and carbonate scales, produced sand, heavy hydrocarbons, tight emulsions, rust particles, other metals and chemicals, and salts. They must be removed periodically from the equipment for disposal. These wastes may be transported to offsite disposal facilities. In some instances, they may be disposed of via landspreading, a practice that entails spreading the wastes over the surface of the disposal area and mixing it with the top few inches of soil. This practice often is done specifically to treat the hydrocarbons present in these wastes through biodegradation. In some instances, the landspread area is periodically watered, worked over to remix the soils and increase aeration, and treated with bionutrients to further enhance hydrocarbon degradation.

Produced water can become a significant waste stream during the production phase. Regulations govern the disposal of this waste stream; the majority of it is disposed of by underground injection either in disposal wells or, in mature producing fields, in enhanced oil recovery wells (i.e., wells through which produced water and other materials are injected into a producing formation in order to increase formation pressure and production).

In some locations, produced water may carry NORM to the surface. Typically, the NORM radionuclides (primarily radium-226, radium-228, and their progeny) are dissolved in the produced water but a portion of the NORM can precipitate into solid form in scales and sludges that collect in pipelines and storage vessels. NORM precipitates could occur on downhole equipment that is being replaced. Proper management of NORM-bearing produced water and solid wastes is critical to prevent both occupational and public human health risks and environmental contamination. NORM wastes generally are a problem associated with long-term operation of an oil or gas field but can be associated with the drilling/development phase. The NORM Technology Connection Web site provides information about the regulation of NORM bearing wastes generated by the petroleum industry.

Health and Safety

Possible impacts to health and safety during production include accidental injury or death to workers and, to a lesser extent, the public (e.g., from an OHV collisions with project components or vehicle collisions with oil or gas workers). Health impacts could result from water contamination, dust and other air emissions, noise, soil contamination, and stress (e.g., associated with living near an industrial zone). Potential fires and explosions would cause safety hazards. Cavitation could ignite grass fires. Increased or reckless driving by oil or gas workers would also create safety hazards. In addition, health and safety issues include working in potential weather extremes and possible contact with natural hazards, such as uneven terrain and dangerous plants, animals, or insects.

In locations where NORM-bearing produced water and solid wastes are generated, occupational and public health risks may occur if the wastes are not properly managed. In particular, workers employed in the cutting and reaming of oilfield pipe, removing solids from tanks and pits, and refurbishing gas processing equipment may be exposed to particles containing alpha-emitting radionuclides that could pose a health risk if inhaled or ingested.

Methane seeps into drinking water wells and under homes has caused health hazards. It is believed that methane seeps increase in areas where coal bed methane is produced. Removal of water during coal bed methane production could exacerbate the potential for underground fires by allowing oxygen to circulate within formerly mined shafts or tunnels.

Land Use

Land use impacts during the production phase would be an extension of those that occurred during the drilling/development phase. However, to some extent, land use can revert to its original uses after the major drilling/development phase is over. For example, farmers can graze livestock or grow crops around the well sites. Other industrial projects would likely be excluded within the gas or oil field. Recreation activities (e.g., OHV use and hunting) are possible, although gun and archery restrictions would probably exist. Project production would deplete recoverable oil and gas reserves. Other mineral resources (e.g., sand and gravel) would remain available for recovery. Coal bed methane production may conflict with livestock and farming operations.

Paleontological Resources

Impacts to paleontological resources during the production phase would be limited primarily to unauthorized collection of fossils. This threat is present once the access roads are constructed, making remote areas more accessible to the public. Damage to localities caused by OHV use could also occur. The potential for indirect impacts (e.g., vandalism and unauthorized collecting) would be greater during the production phase compared to the drilling/development phase, due to the longer duration of the production phase.


Direct socioeconomic impacts would include the creation of new jobs and the associated royalties and taxes paid. Indirect impacts are those impacts that would occur as a result of the new economic development and would include new jobs at businesses that support the expanded workforce or that provide project materials, and associated taxes. Potential impacts on the value of residential properties located adjacent to an oil or gas field would continue during this phase. A well located in close proximity to a residence may have a small adverse effect on property values. This effect could increase as the number of wells increases. Landowners who own the mineral rights within an oil and gas field would receive royalties on any product removed from their property that could offset potential impacts to property values. A coal bed methane well located on a residential property may lower property values, but wells adjacent to a residential property may not have an effect on property values.

Soils and Geologic Resources

Following construction and drilling, disturbed portions of well and ancillary facility sites not required for production would be revegetated. This would help to stabilize soil and geologic conditions. Routine impacts to soils during the production phase would be limited largely to soil erosion impacts caused by vehicular traffic. Any excavations required for maintenance would cause impacts similar to those from development, but at a lesser spatial and temporal extent. The accidental spill of product or other wastes would likely cause soil contamination. Except in the case of a large spill, soil contamination would be localized and limited in extent and magnitude. In areas where interim reclamation is implemented (e.g., reclamation of an individual well is no longer needed), ground cover by herbaceous species could re-establish within one to five years following seeding of native plant species and diligent weed control efforts, consequently reducing soil erosion. The main impact from production would be the depletion of recoverable oil and gas reserves. Other mineral resources (e.g., sand and gravel) would remain available for recovery. Possible geological hazards (earthquakes, landslides, and subsidence) could be activated by oil and gas extraction activities. Although it is rare, the injection of produced water in disposal wells could trigger localized seismic activity.


Impacts to transportation during the production phase would be similar to those for the drilling/development phase. However, daily traffic levels, particularly heavy truck traffic, would be expected to be lower during the production phase compared to the drilling/development phase. For the most part, heavy truck traffic would be limited to periodic visits to a well site for workovers, formation treatment, and collection of produced product or water. The use of pipelines to convey product or produced water to centralized collection facilities or plants would reduce the volume of traffic during the production phase. If a pipeline is not used for oil wells, anywhere from one truckload/month to up to five truckloads/day would be needed.

Visual Resources

Once production facilities are installed, portions of well pads, access roads, and pipeline rights-of-way (ROWs) that are not needed for production would be reclaimed; however, much of the disturbed area would continue to contrast with the natural form, line, color, and texture of the surrounding landscape. This would impact undisturbed vistas and areas of solitude. The aboveground portions of an oil or gas development would be highly visible in rural or natural landscapes, many of which may have few other comparable structures. The artificial appearance of an oil and gas field may have visually incongruous "industrial" associations for some, particularly in a predominantly natural landscape. Any nighttime lighting would be visible from long distances. During the production phase, indirect impacts to visual resources would occur as a result of production activities (e.g., industrial traffic, heavy equipment use, and dust). However, human activity would be substantially lower than during the drilling/development phase.

Water Resources (Surface Water and Groundwater)

During the life of a production well, the integrity of the well casing and cement will determine the potential for adverse impacts to groundwater. If subsurface formations are not sealed off by the well casing and cement, aquifers can be impacted by other non-potable formation waters.

Hydraulic fracturing fluids have the potential to contaminate groundwater drinking reservoirs. Stimulation fluids may penetrate away from the fracture and into surrounding formation. When stimulation ceases and production resumes, these chemicals may not be completely recovered and pumped back into the wellbore, and, if mobile, may be available to migrate through an aquifer.

Most produced water is unfit for domestic or agricultural purposes (e.g., it is extremely salty or contains NORM or toxic compounds). If it is disposed of by release to the surface without treatment, it can cause soil and surface water contamination. The majority of produced water is disposed of via injection in disposal wells or enhanced recovery wells. Groundwater could be impacted during the injection of produced water if the injection well casing integrity is compromised. Regulations govern the disposal of produced water and maintenance of injection wells. If the injection well is not properly completed or is poorly maintained over time, aquifers can be impacted by the injected produced water.

Other potential impacts to water availability and quality during the production phase would include possible minor degradation of water quality resulting from vehicular traffic and machinery operations during maintenance (e.g., erosion and sedimentation) or, if improperly conducted, application of chlorides in dust suppressants or herbicides for vegetation management. A spill or blowout could potentially cause extensive contamination of surface waters or a shallow aquifer. Contaminated groundwater could potentially be discharged into springs or as baseflow into stream channels, leading to surface water contamination.

Removal of water from coal bed methane fields could diminish or dry springs, streams, domestic and stock water wells, and subirrigated lands. Removal of shallow aquifers has caused land subsidence by as much as 40 feet. This could cause damage to utility pipelines, building collapses, and damage to roads. In the Powder River Basin, it has been estimated that a drop of the water level in the aquifer of more than 200 feet has occurred. It is estimated that water levels could drop a total of 600 to 800 feet over the course of coal bed methane development. If coal bed methane production causes aquifers to be depleted, it could force local residents to drill deeper for water.

Discharged water may cause substantial flows in normally dry water bodies such as ephemeral drainages. Some coal bed methane discharges could contain pollutants such as arsenic, ammonia, boron, iron, manganese, radium, and fluoride. Increases in salinity, sodium concentrations, and other soluble pollutants are likely to occur in streams receiving water discharges from coal bed methane developments. By-products of underground fires could include PAHs that could potentially lead to contamination of underground sources of drinking water.