Seismic surveys have been used for many years to site locations for offshore wind facilities and to explore for oil and natural gas and in the Gulf of Mexico and all over the world. Off the U.S. Atlantic coast, the last surveys were conducted about 30 years ago. In the decades since, technologies have advanced dramatically and improved our ability to pinpoint likely reservoirs. Current estimates of the energy resources off our Atlantic coast – based on the old surveys – are now out of date. New surveys using today’s state-of-the-art techniques and technology would give Americans a much better understanding of the energy potential hidden off our shores.
How It Works
To conduct an offshore seismic survey, a sound generator and long strings of sound sensors are towed behind a boat that moves along a preset path. The sound generator, or airgun, periodically releases compressed air into the water to create sound waves. These sound waves, which are comparable to the sound of wind and wave action, marine life, and shipping operations, reflect off subsurface rock layers beneath the seafloor and are recorded by the sensors at the surface. Survey ships typically move at about 4.5 to 5 knots (~5.5 mph), so the sound does not last long in any one place.
Scientists use the recorded survey information to produce detailed three dimensional maps of the subsea geology that help locate likely reserves of oil and natural gas. The maps are used to determine the safest and most efficient drilling locations, which reduces the environmental footprint of offshore drilling.
Read more on why and how seismic surveys are performed on America's Offshore Energy: Seismic Surveys Why and How
Seismic surveys are safe and highly regulated. The best science and research, including studies from the U.S. Department of the Interior, show that seismic surveys have little-to-no effect on marine mammal populations. Even so, operators and regulators work together to minimize the already negligible potential impact on marine life.
Before operations begin, animal movement and behavior patterns are analyzed and to identify permissible survey areas. Surveyors begin the process at low volumes and gradually increase the sound, giving animals that wish to leave the area time to do so. During operations, onboard acoustic and visual monitoring is used to look for sensitive marine life in the vicinity. If any are detected, survey operations immediately halt and only restart once the area is clear.
Read more on seismic surveys safety, science, and research America's Offshore Energy: Seismic Surveys Safety, Science, and Research
Benefits of Seismic Surveys in Oil and Natural Gas Exploration
Today, advancements in seismic technology have helped find, drill and produce oil and natural gas with the least risk and the least possible impact to the earth. As operators explore for oil and gas, the use of geophysical technologies helps to reduce risk in regards to cost, safety and damage to the environment. Seismic information is used to accurately plan locations for wells, reducing the probability of drilling dry wells and consequently the need for further drilling, minimizing the environmental impact of the oil and gas exploration.
See links to the five one-page reports produced by the International Association of Geophysical Contractors (IAGC) below: