Seismic Hydrocarbon Exploration

Abstract

An application of an external force, on part of a medium (elastic medium), leads to creation of internal opposing forces which intend to resist the deformations caused by that external force. Typical forms of the resulting deformations are changes in volume and/or in shape which are created at the affected location. In consequence, the medium will return to its original condition after the external force is removed. This property of resisting of changes in volume and in shape and return to original conditions after removal of the external force is called (elasticity). Provided that the changes are small, rock media in nature are considered to be perfectly elastic in nature. As a result of the elasticity property of media, the changes (volume and shape changes) oscil- late about their neutral positions and, at the same time, propagate away from the energy source-location. Energy transfer in this manner (motion that leaves out no permanent distortions) is commonly referred to as (wave motion). The fundamental condition for the creation and propagation of seismic waves (seismic field) is a source of mechanical energy of impulsive type which is initiated within an elastic medium. The energy source may be natural (as in earthquake-generated waves) or artificial (as in firing of a dynamite charge). In both cases wave motion of elastic waves are generated and can be recorded by the appropriate detection instru- ments. These are normally referred to as the (seismic waves).