A Forecast of Marine Seismic Exploration for oil
Authors: Johnson Curtis H. , Blue Donald M. 
Published: October 2008

Introduction
In March of 1956, we presented to a joint AAPG-SEG-SEPM audience in Long Beach, California, a projection of how much more marine seismic exploration remained to be done. We concluded, and it was widely quoted in both petroleum trade magazines and brokerage analyses at the time, that, assuming an average rate of 500 marine seismic crew months per year, it would take 127 years to complete the job. In the present discussion, we will reexamine the amount of remaining exploration, based on four more years of historical performance. We are making this reexamination because we were invited to do so, because we feel it may be helpful to firms planning offshore seismic exploration ventures, and because of the increasing interest shown in the oceans and oceanography as a whole, as witnessed by the very existence of this First Annual Offshore Technology Conference.

Summary
In the following paragraphs, we will indicate how we derive our projections for the future, based on the total area of the Free World's continental shelves, calculated o a depth of 1000 feet; on the classification of this area as to petroleum potential according to Lewis G. Weeks; on the established rate of seismic reconnaissance surveying; on the established record of additional detailing and re-surveying in heavily explored areas; and on the impact of increasing technology and its effect on the amount of work done in the currently used measure of seismic activity, the "crew-month."
Using these contributing factors, we estimate about 60,000 crew-months remain to be done. We suggest that the remaining crew-months will be distributed in time as follows: that activity will peak about the year 2000, and decline to less than 50 crew-months per year before the year 2100. Thus, we continue to project that 120 years remain in the effective life of the marine seismic industry, but, superimposed on our projected activity curve are cyclic fluctuations due to such unpredictables as the 6-day Mideast war, the Biafra revolution in Nigeria, and the recent oil spillage in the Santa Barbara Channel. Finally, we point out a need for a redefinition of the term "crew-month", to take -into account the ever-increasing efficiency of marine seismic crews.

Continental Shelf Areas
A map of the world shows that, in general, the continental shelves occupy a relatively narrow band around the continents and some islands.
Six productive shelf areas, on which control data were obtained for this study, are circled in Figure 1, and their relative sizes in the right-hand chart of Figure 2. These areas are: the U.S. Gulf Coast; the coast of Southern California; Cook Inlet, Alaska; Venezuela-Trinidad; the Persian Gulf-Red Sea area of the Middle East; and the Nigerian Coast. Although these six areas are not the only productive shelf areas of the world, (two other recent areas are included in this chart) they do account for the bulk of the production, but less than 3% of the total shelf area. About 40% of the Free World's presently productive shelf area is in the United States; nearly half in the Western Hemisphere.