The possibility of hydraulic fracturing causing induced seismic events felt at the earth’s surface is rare. In the U.S., these wells have been used since the 1930s and are regulated by the U.S. When properly planned, operated, and monitored, fluid disposal wells are safe. Induced seismicity has long been a low, but recognized risk of underground fluid disposal wells, one of the ways that the oil and gas industry disposes of produced water, which is the water that is brought to the surface when extracting oil and natural gas. In addition, Chevron complies with all laws that require disclosure and reporting to specific governmental agency databases. Some Frac Focus reports may exclude chemical ingredients that are considered proprietary by the vendors supplying them. Chevron discloses vendor-provided information concerning the chemicals used in its hydraulically fractured wells in the United States at and in Canada at Safety Data Sheet level-only information is provided to Frac Focus. We support giving the public access to information related to chemicals used in hydraulic fracturing. Some of these same substances can also be found in food and beverages. The remaining 1 percent consists of a small number of chemicals added to improve the efficiency and effectiveness of fracturing. Water and sand constitute more than 99 percent of fracturing fluid. natural gas production comes from wells that have undergone hydraulic fracturing. Today, nearly half the oil produced in the U.S. Hydraulic fracturing has been in use since the 1940s. Such activities may include assessing the subsurface geology to identify and mitigate risks associated with groundwater aquifers, faults and geological pathways, historical wells in the area and shallow gas reservoirs. We use pre-drilling and planning activities to identify areas of potential environmental, geologic or archaeological sensitivity. For example, micro-seismic surveys of shale gas wells in the eastern United States show that fractures are separated from groundwater by more than a mile of rock - a distance as deep as the Grand Canyon. Because fracturing is done thousands of feet beneath the groundwater aquifer, the potential for cracks to leak gas or fracturing fluids into groundwater is extremely low. We perform pressure tests to ensure the well’s integrity, and conduct monitoring and various tests over the life of the well, which may include cement evaluation logs, temperature, acoustic or ultrasonic measures, to verify long-term integrity. Our wells have multiple layers of steel casing and cement that form a continuous barrier between the well and the surrounding formations. We take steps to protect groundwater during hydraulic fracturing and over the life of the well. Similar activities occur in producing shale gas and tight oil from other Chevron operations, including the Permian Basin. Chevron monitors the well throughout its life to verify integrity and when the well stops producing, the land is restored to its natural state. Once drilling and completions processes are complete, the well is ready to produce oil or natural gas or both for decades. By combining this process with horizontal drilling, more of the resource can be reached with fewer wells and less earth disturbance. A key aspect of releasing the resources from the rock formations is the use of hydraulic fracturing (commonly known as "fracking"), which involves injecting water, sand and a small amount of chemical additives under pressure to crack the rock and release the trapped oil and gas. These include obtaining permission to drill from the landowner and government, constructing a temporary drilling site, and using a rig to drill the well. Development of natural gas and oil resources from shale and tight rock involves a number of steps.
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