Seismic surveying
OwnerIain M. Mason, Geoffrey M. Jackson +3inventors
InventorsIain M. Mason, Geoffrey M. Jackson, Delman Lee, David S. R. Campbell, Charles C. Mosher
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Abstract
A method of seismic surveying uses seismic waveguides in the earth. Seismic energy is transmitted from outside the waveguide and detected within the waveguide or vice-versa. Coupling of energy between the outside and the inside of the waveguide is effected by energy leakage at coupling sites where the waveguide departs from planarity. The method analyzes seismic signals to determine the position and nature of coupling sites and the propagation characteristics of the waveguide.
Claims17
A method of seismic surveying which utilizes a seismic waveguide in the earth wherein a first region is defined as the region within the waveguide and a second region is defined as the region outside of the waveguide, the method consisting of generating seismic energy by means of one or more energy sources situated in one of said regions;
- detecting seismic energy which leaks by energy coupling from one of said regions to the other of said regions;
- detecting seismic energy by means of one or more transducers in the other of said regions and analyzing the detected seismic energy to locate localized deviations in the planarity of the waveguide which give rise to said energy coupling.
A method of seismic surveying as claimed in any one of the preceding claims wherein a plurality of seismic traces is derived, each being in respect of seismic energy transmitted between a position in the waveguide and a respective position outside the waveguide, and wherein a model is applied to the traces to determine energy transmitted by said energy coupling, the model assuming that coupled energy has a transmission time comprising two components consisting of a constant time component within the waveguide and a variable downgoing time component outside the waveguide, wherein the downgoing time component is a function of the horizontal offset of the respective position outside the waveguide from an energy coupling site at the waveguide.
Dependencies are inferred from the claim text.