Patent ID: 7467685

Claim:
An apparatus for generating a seismic signal in a wellbore, comprising: an elongated housing configured to be disposed in the wellbore; a piston slidably disposed in an internal bore in the elongated housing; a strike plate disposed on the elongated housing proximate one end of the internal bore, wherein the strike plate has a substantially flat surface opposite the side to be hit by the piston such that a majority of fluid waves generated will propagate in a direction parallel with the longitudinal axis of the elongated housing; a deflecting mass having a cone-shaped surface disposed in the elongated housing and configured to deflect the fluid waves by the cone-shaped surface into directions that are substantially perpendicular to the longitudinal axis of the elongated housing; a slotted sleeve disposed around the strike plate to allow for fluid communication between fluids outside the elongated housing and fluids in a region between the strike plate and the deflecting mass inside the elongated housing; and an energizing mechanism configured to move the piston to hit the strike plate.