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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 66 (1982)

Issue: 5. (May)

First Page: 602

Last Page: 602

Title: Evolution of Offshore Seismic Exploration: ABSTRACT

Author(s): W. Harry Mayne

Article Type: Meeting abstract


True offshore seismic exploration had its inception in 1947. Although considerable work had been done prior to this in coastal estuaries, wetlands, and inland waterways, the methods used were adapted almost entirely from the conventional land operations.

The first tentative ventures into the real offshore environment indicated that radical departures from land procedures were required in the following areas: (1) cables and receivers, (2) positioning (surveying, navigation), and (3) seismic energy sources.

Leroy Paslay's continuous tow streamer cable and the replacement of the velocity-responsive geophones with pressure-sensitive hydrophones were significant early breakthroughs.

At first, line positions were determined by land-based optical surveying methods, and shot locations were marked with buoys placed by wire-line distance measurements or triangulation. As work progressed farther offshore, a number of radio location systems were adapted or developed to provide positioning without the need for marker buoys. The present satellite and inertial navigation systems and the projected development of the new Global Positioning System represent continuing developments in this area.

Dynamite and other chemical explosives were exclusively used as seismic sources for a number of years despite their many disadvantages. Development of suitable non-dynamite energy sources was mandated by the advent of the common reflection point method, and the Lamont-type Previous HitairNext Hit Previous HitgunNext Hit has become the most popular present-day source.

Concurrently, the vessels used were progressively upgraded from converted shrimp boats to surplus Previous HitairTop-sea rescue vessels and then to the currently popular 165 ft mud boats.

Individually, these developments may appear to be only evolutionary. In the aggregate, however, they represent a major revolution when compared to our first timid ventures of the late 40s.

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Copyright 1997 American Association of Petroleum Geologists