Seismic imaging is a tool that bounces sound waves off underground rock structures to reveal possible oil- and gas-bearing formations. Seismologists use ultrasensitive devices called geophones to record the sound waves' echoes within the earth. By studying the echoes, petroleum geologists seek to calculate the depth and structures of buried geologic formations. This analysis may help them identify oil- and gas-bearing reservoirs hidden beneath the earth's surface.
What Are the Benefits?
Energy companies have been using seismic imaging for about 80 years. However, ongoing technological developments have made geologists' efforts to find oil and gas beneath the surface more precise and effective.
Sophisticated 3-D imaging creates high-definition pictures of subsurface geology. The result is similar to an X-ray scan or medical sonogram that covers thousands of square miles and extends 10 miles (16 km) or more into the earth. Software to analyze these images continues to improve, and more advanced computers now allow scientists to examine the data within days rather than months, speeding the discovery and ultimate production of oil and gas.
Recording multiple 3-D surveys at different times produces 4-D information. The images show a reservoir at different stages of depletion, allowing petroleum engineers to improve recovery and produce the resource more efficiently.
What Chevron Is Doing
Chevron's proprietary seismic imaging technology helped the company achieve a superior exploration discovery rate of 57 percent in 2010. This technology allows Chevron scientists to see beneath the earth's surface more clearly and accurately than ever before. Using these proprietary tools, researchers have been able to find significant oil and gas reservoirs in increasingly challenging areas, such as beneath thick mountains of salt in the deepwater portion of the U.S. Gulf of Mexico.
Seismic images have become more accurate with the development of more sophisticated velocity models, which contain information about the speed with which the seismic waves travel through the rock layers. This information is critical for unraveling the geologic secrets hidden below. Recorded echoes produce a vast amount of data, and powerful supercomputers are required to process and analyze the data to form a 3-D image. Accuracy is essential: The better the images, the fewer the number of dry holes, which improves the likelihood that an exploratory well will confirm a discovery and move toward production.
Leading the Way in Seismic Imaging
In 1982, Chevron became one of the first energy companies to use a supercomputer and quickly adopted more advanced parallel computers that improved seismic results and reduced costs exponentially. Fifteen years later, we introduced the industry's first 3-D visualization centers, which offered a multilayered deep-earth panorama of seismic and well data, cutting review time from days to hours and at a fraction of the cost. Since then, Chevron has continually built upon this capability, constantly investing in ever-more-powerful computers as they become available to enable faster and better analysis.
Seismic imaging also helps well-site teams optimize drilling before it actually starts. Chevron scientists estimate that 85 percent of well problems can be traced back to poor subsurface modeling and associated well planning. A precise seismic image and subsurface model can ensure major savings during every phase of operation.
Updated: June 2011