Robert A Porter

US Patent:

49531360, Aug 28, 1990

Filed:

Jul 18, 1986

Appl. No.:

6/887307

Inventors:

Masahiro Kamata - Tokyo, JP
Shitomi Katayama - Kanagawaken, JP
Francis Mons - Bonnelles, FR
Robert Porter - Bellevue WA

Assignee:

Schlumberger Technology Corporation - New York NY

International Classification:

G01V 100

US Classification:

367 25

Abstract:

A downhole seismic exploration device comprises a seismic detector such as a geophone and a magnetic clamp, supported by Q-rings in an open cradle carrier which can be secured to a cable linking several such devices into an array. The array is lowered into a cased borehole and the magnetic clamps are operated to clamp the devices temporarily to the casing. Seismic signals detected by the geophones are transmitted to the surface via the cable, the O-ring supports acting to reduce or eliminate transmission of vibrations from the borehole fluid and the cable via the carrier to the geophone. The array is then unclamped and moved to another location in the borehole and the operation repeated. The magnetic clamp comprises a rotatable permanent magnet with radial poles disposed between a pair of parallel pole piece plates protruding on each side of the device and separated by non-magnetic blocks on each side of the magnet. When the magnet poles are aligned parallel to the pole piece plates the magnetic flux extends along closed paths entirely within the pole pieces and there is no clamping action.

US Patent:

D2831007, Mar 25, 1986

Filed:

Oct 18, 1982

Appl. No.:

6/434756

Inventors:

Robert H. Porter - Tacoma WA

US Classification:

D 8 71

US Patent:

50444603, Sep 3, 1991

Filed:

Mar 8, 1990

Appl. No.:

7/490187

Inventors:

Masahiro Kamata - Tokyo, JP
Shitomi Katayama - Kanagawaken, JP
Francis Mons - Bonnelles, FR
Robert Porter - Bellevue WA

Assignee:

Schlumberger Technology Corporation - Houston TX

International Classification:

G01V 100

US Classification:

181102

Abstract:

A downhole seismic exploration device comprises a seismic detector such as a geophone and a magnetic clamp, supported by O-rings in an open cradle carrier which can be secured to a cable linking several such devices into an array. The array is lowered into a cased borehole and the magnetic clamps are operated to clamp the devices temporarily to the casing. Seismic signals detected by the geophones are transmitted to the surface via the cable, the O-ring supports acting to reduce or eliminate transmission of vibrations from the borehole fluid and the cable via the carrier to the geophone. The array is then unclamped and moved to another location in the borehole and the operation repeated. The magnetic clamp comprises a rotatable permanent magnet with radial poles disposed between a pair of parallel pole piece plates protruding on each side of the device and separated by non-magnetic blocks on eahc side of the magnet. When the magnet poles are aligned parallel to the pole piece plates the magnetic flux extends along closed paths entirely within the pole pieces and there is no clamping action.