Introduction
Seismic exploration is the use of seismic energy to probe beneath the surface of the earth, usually as an aid in searching for economic deposits of oil, gas or minerals, but also for engineering, archeological and scientific studies. In exploration seismology, the seismic method is applied at or near the earth's surface to measure the elastic properties of the subsurface and to detect variations in those properties. Variations and discontinuities in subsurface elastic properties may be indicative of changes in lithology or pore fluids. Exploration seismology has been applied for subsurface investigations of depths as great as 150 km; however it is particularly useful for depths up to 10 km. For these depths, the seismic method is capable of detecting and spatially resolving features at scales as small as tens of meters or less. This resolving power is significantly finer than the resolving ability of other remote geophysical methods for this depth regime. Because this region of the earth's subsurface includes nearly all of its oil and gas reserves, exploration seismology plays a prominent role in the energy industry. In the following introduction to exploration seismology, I start with a short treatment of seismic wave propagation theory. I then describe seismic exploration from a methodological point of view; I divide the seismic method into data acquisition, data processing and data interpretation, and I discuss each component separately. |
Walter Kessinger