Abstract: Technological Forefront of Exploration
Max G. Pitcher
Conceptual developments in the earth sciences have been dramatic during the past 10 to 15 years. These developments have helped to keep significant domestic U.S. discoveries at nearly constant levels since 1960 even though the number of wildcat wells has decreased. By applying new exploration techniques, many new discoveries are being made that could not have been found using 15 to 20-year old methods. Four of the most significant conceptual developments of recent years are plate tectonics, environmental stratigraphy, organic geochemistry, and geoseismic modeling.
On the basis of plate-tectonics theory basins throughout the world which have giant oil and gas fields can be divided into four major tectonic groups. These groups and their percentage of giant accumulations are: subduction-related basins 7%, rift-related basins 9%, drift-related basins 4%, suture-related basins 74%.
The Smackover development illustrates the utility of environmental stratigraphy. In this trend carbonate rocks that are related to modern-sediment types control the distribution of giant oil and gas fields. Combining preferred paleoenvironments with present structure guides the search for new fields.
Organic geochemistry describes the chemical and thermal history of basins. This allows geologists to discriminate among basins and to isolate those capable of generating giant quantities of oil and gas. The Maranon basin in Peru was analyzed with these techniques and formed a data base which assisted investment decisions in this foreign play.
Geoseismic modeling allows explorationists to detect stratigraphic traps ahead of the drill, to be more exact in seismic interpretation of complex structures, and in some cases to map the extent of oil and gas accumulations directly by interpreting acoustic hydrocarbon indicators. Onshore stratigraphic traps have been mapped and offshore-seismic stratigraphy and hydrocarbon indicators have a significant impact on offshore bidding.
AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC