| 摘要 |
<p>1,193,507. Seismic prospecting. INSTITUT FRANCAIS DU PETROLE DES CARBURANTS ET LUBRIFIANTS. 14 June, 1967 [14 June, 1966; 12 July, 1966], No. 27528/67. Heading H4D. [Also in Division F3] According to one aspect the invention comprises an underwater seismic prospecting system utilizing a plurality of intermittent sources of elastic waves immersed at different depths and with their timing so controlled that watersurface reflections are reduced at submerged receiving means. According to another aspect the invention comprises an underwater seismic prospecting system utilizing receivers at different depths, their outputs being delayed inter se to reduce water-surface reflections, and the or each emitter comprises an exploding cartridge. In one embodiment four explosion generators are utilized, each comprising a flexible tube 1 with a metallic mouth-piece 2 having an insulating seat 3 for a cartridge 4 and a circuit 5 for firing the cartridge; the other end of the tube is connected to a cartridge loading device incorporating a loading tube 6 provided with a pneumatic jack 19 controlling cartridge loading, Fig. 4 (not shown) (see Division F3). The cartridges are housed in a distributer 8. The seismometers are a horizontal spread. In a second embodiment a single explosion generator and four submerged and vertically-spaced seismometer spreads (H1 . . . H4) of spacing e are utilized, the amplified electrical signals from three of the spreads being subjected to delays e/v, 2e/v, 3e/v where v is velocity of wave propagation, and the signals then being added, Figs. 5, 6 (neither shown). Digital processing of the amplified signals may be adopted, Fig. 7 (not shown). The outputs of the seismometers in a spread may be utilized separately, Figs. 9, 10 (neither shown). The wave generators in the first aspect may be spark pulse generators as described in Specification 1,170,536.</p> |
