Geophysical interpretation is a fundamental part of petroleum and mineral exploration. The decision to drill for oil or minerals often depends on our ability to obtain reliable models of the earth by using geophysical data gathered at the earth's surface or in boreholes. Interpretation involves determining the geologic significance of geophysical data and generally integrates all available geologic and geophysical information. It is linked closely to other disciplines such as data acquisition and processing.
Interpretation is a process of estimating an earth model whose response is consistent with all available observations. Examples of geophysical observations might include seismic, gravity, magnetic, electrical, electromagnetic, and borehole data. By this definition, interpretation can be considered a type of geophysical inversion.
Because data sets are always limited in size and scope, several interpretations will be consistent with available data. In other words, our interpretations will show ambiguity, and data fitting alone usually is inadequate. Although interpretation is built on the scientific foundations of geology and geophysics, it is often a fascinating mixture of art and science.
Given the various possible mathematical solutions that describe our data, which interpretation should we use? In such cases, it is helpful to rely on experience in geologic case histories and to have insight into geophysical constraints for our models.
With their experience of related exploration plays as a guide, successful interpreters in exploration generally will choose the most optimistic interpretation that is consistent with available data. Optimism often leads to further data acquisition (for example, shooting more seismic
Figures & Tables
Fundamentals of Geophysical Interpretation, SEG Geophysical Monograph Series No. 13, is a practical handbook for the petroleum geophysicist. Fundamental concepts are explained using heuristic descriptions of seismic modeling, deconvolution, depth migration, and tomography. Pitfalls in processing and contouring are described briefly. Applications include petroleum exploration of carbonate reefs, salt intrusions, and overthrust faults. The book includes past, present, and possible future developments in time-lapse seismology, borehole geophysics, multicomponent seismology, and integrated reservoir characterization.