String of sondes
AssigneeCompagnie Generale de Geophysique
InventorGildas Omnes
Life of this patent
Estimating the term…
Abstract
A string of sondes is designed to be lowered down a borehole by means of a cable in order to detect the arrival of seismic waves therein, the sondes including retractable anchor means that are hydraulically actuateable and that are connected by a hydraulic circuit to a common source of hydraulic pressure. The string includes means for putting said hydraulic circuit to ambient pressure, said means being connected to said cable and being adapted to act on said hydraulic circuit in order to cause said anchor means to be retracted when a traction force exceeding a selected value is exerted on said cable.
Claims9
A string of sondes for use in a borehole to provide seismic signals when energized remotely,
- each sonde including hydraulically operable anchoring means adapted to being remotely operated for engaging the wall of the borehole as a result of hydraulic pressure in a hydraulic circuit,
- an elongated element supporting said sondes in a generally linear array so that said sondes can be deployed in the borehole and withdrawn from the borehole by applying a tension/traction force to said elongated element,
- said elongated element having a first part slideably receiving a second part thereof, and said hydraulic circuit having a vent passage defined by said first and second parts,
- valve means normally closing said vent passage to allow hydraulic pressure to operate said anchoring devices, and
- said vent passage acting to dump said hydraulic pressure to said anchoring devices when said first and second parts have moved relative to one another in response to tension/traction force in excess of a predetermined force.
Dependencies are inferred from the claim text.