Apparatus and method for detecting seismic waves in a borehole using multiple clamping detector units

An apparatus for detecting seismic waves in a borehole comprising:

• (a) a plurality of small, light-weight, clamping detector units, each of said units having an hydraulically actuated clamp;
• (b) a hydraulic pump adapted to actuate said hydraulically actuated clamp on each of said plurality of clamping detector units;
• (c) conduit means connecting said pump to said clamping detector units so that said clamping detector units may be hydraulically clamped to a wellbore with a large force by activation of said clamps;
• and
• (d) a digitizer connected to said clamping detector units to condition signals from said detector units.

An apparatus for detecting seismic waves in a borehole comprising:

• (a) a plurality of clamping detector units, each of said units comprising at least one geophone enclosed in a light-weight housing having an hydraulically actuated locking arm which moves outwardly to engage the borehole wall and a piston unit adapted to actuate said locking arm;
• (b) a hydraulic pump, said hydraulic pump adapted to actuate said piston unit on each of said plurality of clamping detector units;
• (c) conduit means comprising a hydraulic hose connecting said pump to said clamping detector units so that said clamping detector units may be hydraulically clamped to a wellbore with a large force by activation of said locking arms;
• (d) equalization means for equalizing a pressure in a piston cavity defined by said hydraulic piston unit to a pressure in said borehole surrounding said detector units;
• and
• (e) a digitizer connected to said geophones by a plurality of wires to condition signals simultaneously from said geophones.