초록 ▼

An axially extended downhole seismic source is disclosed. In one embodiment, the seismic source includes multiple pressure storage chambers, each having an inlet valve and an outlet valve. The inlet valve is coupled between the pressure storage chamber and the interior of the drill string, and the o

An axially extended downhole seismic source is disclosed. In one embodiment, the seismic source includes multiple pressure storage chambers, each having an inlet valve and an outlet valve. The inlet valve is coupled between the pressure storage chamber and the interior of the drill string, and the outlet valve is similarly coupled between the pressure storage chamber and the annular space around the drill string. A compressible fluid may be provided in the pressure storage chambers, and pistons may be positioned to contact the compressible fluid. For each pressure storage chamber, an inlet piston contacts the compressible fluid and fluid inside the drill string, while an outlet piston contacts the compressible fluid and fluid in the annular space around the drill string. When the outlet valve is closed, the inlet valve can be opened to allow pressure inside the drill string to compress the compressible fluid inside the pressure storage chamber. Subsequently closing the inlet valve and opening the outlet valve causes fluid to be ejected into the annular space, thereby generating seismic waves. The use of multiple pressure storage chambers allows the pressure front from the seismic source to be extended axially to advantageously increase the fraction of seismic energy transmitted into the formation while preventing damage to the formation.

대표청구항 ▼

1. A seismic source which comprises:a first outlet to an annulus around the seismic source; a first outlet valve coupled between the first outlet and a first pressure storage chamber; a first inlet from an interior of a tubing string; a first inlet valve coupled between the first inlet and the first

1. A seismic source which comprises:a first outlet to an annulus around the seismic source; a first outlet valve coupled between the first outlet and a first pressure storage chamber; a first inlet from an interior of a tubing string; a first inlet valve coupled between the first inlet and the first pressure storage chamber, wherein pressure is stored in the first pressure storage chamber via the first inlet and the first inlet valve; a second outlet to the annulus around the seismic source, wherein the second outlet is axially spaced apart from the first outlet; and a second outlet valve coupled between the second outlet and a second pressure storage chamber.