Producing wells are drilled at depths thousands of feet greater than the geologic layers where aquifers and groundwater flow. This means that there are many layers of impervious rock between our operations and any drinking water sources. We conduct baseline assessments to evaluate the quality of the groundwater to ensure that our activities are not negatively affecting the freshwater sources in the area.
In order to protect groundwater, steel casing (solid steel tubes) and cement are used to create a multi-layer barrier between the well and any ground water sources. The tubes are placed in the well and cemented in place to create a strong physical barrier the runs the length of the well. The types of materials used and testing requirements for these materials is highly regulated. Before hydraulic fracturing can begin the wells are tested at pressures exceeding maximum operating pressures to ensure mechanical integrity before operations begin. After being put in use, wells are continually monitored to ensure that there are no cracks or leaks in the well casing.
During well completion and production operations, water that was trapped within the oil and gas producing formations is returned to the surface and captured. This water is alternately called produced water, saltwater, or brine (as it generally contains large concentrations of dissolved minerals and salts). After being injected into the well, a portion of the fracturing fluid will be produced back (returned) to the surface. The amount of fluid that returns to the surface depends on the local geological characteristics. The rest of the water remains in the formation and may be slowly produced over a long period of time.
Any water captured during the drilling and hydraulic fracturing process is either recycled and reused in operations or disposed of according to government guidelines and regulations. The primary method of disposal method for all water used in oil and gas extraction is to inject the water into a Class II disposal well. This practice has been used for years as a safe method for the disposal of wastewater from industrial activities and is stringently regulated.
Low concentrations of naturally occurring radioactive material (NORM) are found in all soil and rock formations. As a result of drilling, these elements are brought to the surface as radioactive solid waste and may also be present in produced water. These materials emit low-level radiation, which generally is so low as to not present a health hazard. The potential accumulation of these radioactive elements within equipment and in waste materials can also present a very low exposure risk. Therefore, equipment is regularly inspected for accumulation and any materials are carefully collected and disposed of. The disposal of NORM waste is regulated by local authorities and is often done at specially permitted sites.
Induced seismicity refers to any vibration or minor earthquake caused by human activity. Seismicity can be initiated by impounding water, quarrying, tunneling or heavy vehicle movement. By design, hydraulic fracturing releases energy deep underground creating very low levels of induced seismic activity. In most cases, these vibrations are of very low magnitude and cannot be felt at the surface or cause damage to surface structures or nearby wells. In some areas of the U.S., where seismicity has been detected in the past, seismicity is monitored and reported to ensure that activities do not create larger magnitude events.
Flaring & Air Emissions
In the absence of suitable infrastructure or storage for the natural gas which comes out of a well, it may be necessary to burn - or “flare” - the gas. The main by-product of this burning process is carbon dioxide. We have set stringent internal targets to reduce our own emissions and are committed to ending routine flaring in our operations by 2030. By reducing flaring, we prevent wastage of a valuable energy source, and lower emissions. Our aim will always be to utilize the resource, industrially or commercially. For example, in North Dakota, US we have taken gas that would be flared and used it to fuel our drilling rigs.
The processing and storing of hydrocarbons can also have the potential to release unintended air emissions generally referred to as “fugitive emissions”. These types of emissions typically include carbon dioxide as well as methane. Equinor regularly monitors, reports, and works to continuously reduce these types of emissions. When leaks are identified, we replace or upgrade the leaking equipment and incorporate what we’ve learned into future system designs.
Air emissions from our operations are regulated at the local, state, and federal levels in the US, and Equinor follows all regulatory requirements.
Equinor has partnered with multiple organizations to further drone technology to enable accurate and regular measurement and monitoring of fugitive emissions. Learn more about these activities and our position on the regulation of methane emissions: We're reducing methane emissions in the US - Supporting direct methane regulation - equinor.com
Reducing air emissions from our operations is a critical component of our ambition toward becoming net-zero by 2050. Read more about our climate roadmap: Our new Climate Roadmap - equinor.com
We strive to be a good neighbor and live our corporate values of caring and openness with all our stakeholders. Many of our employees and contractors live, work, and are active members of the communities in which we operate. We are actively engaged in keeping local stakeholders informed about our activities. We have regular dialogues with officials at all levels of government to share our plans and address concerns. We also support community needs with giving and service initiatives focused on public education, emergency response, and the environment.
Equinor has worked closely with other operators to develop a best practice guide for engaging local communities; addressing needs and concerns where oil and gas operations occur. These guidelines are available here: ANSI/API Bulletin 100-3, Community Engagement Guidelines