No wholly new exploration techniques have evolved during the past 10 years. However, geologists and geophysicists have learned that there is more to discovering oil fields than the detection of closed structures and the selection of sites where rocks have sufficient porosity to hold oil. They have realized that oil fields are located only in favorable geological settings characterized by certain large-scale geological features. They also have realized that it is possible, using geology and geophysics,

End_Page 1563------------------------------

to analyze geological information intelligently, including well cuttings, surface samples, surface and subsurface geological maps, seismic records, gravity information, and magnetic information in order to determine whether or not the local geological environment is conducive to oil accumulation. Modern exploration techniques make possible the localization of potential oil reservoirs in such sedimentary features as limestone reef complexes, deltas, beaches, etc. The most difficult aspects of this modern exploration concept are the correlation of geological and geophysical data and the reduction of geophysical data into meaningful geology.

The past decade has witnessed a rebirth of sedimentary petrology in oil-finding. This renaissance involves the study of Recent sediments as a key to the past and the application of geochemistry, paleontology, and petrology to the definition of sedimentary depositional patterns. During the past 10 years, geophysicists not only have improved their equipment for better measurements of the properties of sediments but also have made significant progress in developing methods of presenting geophysical data in geological form.

End_of_Article - Last_Page 1564------------