Abstract A conventional logging instrument is adapted to traverse a slanted or deviated earth borehole on the end of a conventional logging cable. A heavy, streamlined sinker bar is adapted to be fitted over the cable and to slide freely thereon. Upper and lower stop clamps, separated by approximately 100 feet of cable, are provided on the cable with the lower stop clamp being located approximately 200 feet above the logging instrument. The sinker bar is adapted to slide freely between the upper and lower stop clamps. Since it is unlikely that the logging tool and the sinker bar will become stuck at the same time in a highly deviated borehole, one of two things can happen. If the sinker bar becomes stuck, the cable passes freely through the center of the sinker bar without impeding the logging tool until the upper clamp reaches the limit of its travel. If at that point the logging instrument is descending freely, it can dislodge the sinker bar with a gravitational force. If the logging instrument becomes stuck while the sinker bar is free, the sinker bar will rest on the lower clamp and push on the logging cable to impel it downward. By the concerted action of the sinker bar and logging tool, the probability of reaching greater depths within the deviated borehole is increased. A spring or other such shock absorber is affixed to each of the clamps to prevent transfer of excessive inertial force during the operation of the system.
A system for logging earth boreholes, comprising: an elongated well logging instrument adapted to traverse an earth borehole; a cable leading from the earth's surface attached to said instrument; hoist means at the earth's surface for winding and unwinding said cable to thereby enable said instrument to traverse said earth borehole; means slidably attached to said cable and adapted to traverse said earth borehole; and first and second stop means on said cable intermediate the said hoist means and the said logging instrument and on opposite sides of said slidable means, thereby limiting the sliding movement of said slidable means.
Claim 2
Independent Claim
100 words
A system for logging earth boreholes, comprising: an elongated well logging instrument adapted to traverse an earth borehole; a cable leading from the earth's surface attached to said instrument; hoist means at the earth's surface for winding and unwinding said cable to thereby enable said instrument to traverse said earth borehole; means slidably attached to said cable and adapted to traverse said earth borehole; and first and second stop means on said cable intermediate the said hoist means and the said logging instrument and on opposite sides of said slidable means, thereby limiting the sliding movement of said slidable means.
Claim 3
Dependent Claim
18 words
The system according to claim 1, wherein at least one of said stop means includes shock absorber means.
Claim 4
Dependent Claim
19 words
The system according to claim 1, wherein each of said first and second stop means includes shock absorber means.
Claim 5
Dependent Claim
24 words
The system according to claim 1, wherein each of said first and second stop means is some distance removed from the said logging instrument.