Acoustic caliper logging

Claim 2

In a well logging system where an acoustic transducer in a logging tool acoustically scans the circumference of the borehole repeatedly and receives acoustic energy reflected from the walls of the borehole in timed relation to transmission dependent upon borehole diameter, the improvement which comprises: providing a continuous probing of the travel time of acoustic energy from said transducer to said wall and back to said transducer over each of a plurality of vertical segments of said borehole wall where said segments are circumferentially displaced one from the other, and recording a reflection travel time function separately for each of said segments as a function of depth of the scan level in said borehole.

Claim 3

The method of claim 1 wherein said segments are vertical with centers thereof displaced approximately 90* one from another.

Claim 4

The method of claim 2 wherein each said segment extends approximately 5* in azimuth.

Claim 5

The method of claim 2 wherein electrical charges are stored, one for each segment, with each charge adjusted continuously in dependence upon diameter of the borehole at the position of a segment and where each said charge is continuously recorded on a depth related scale where trace amplitude represents hole diameter.

Claim 6

A well logging system which comprises: a. a borehole tool having an acoustic transducer actuated acoustically to scan the circumference of the borehole repeatedly and to receive acoustic energy reflected from the walls of the borehole in timed relation to transmission dependent upon borehole diameter, b. means to generate a scalar function representative of the travel time of acoustic energy from said transducer to said wall and back to said transducer, and c. means to record said function separately for each of a plurality of vertical segments of said borehole wall where said segments are circumferentially displaced one from the other in relation to scan depth in said borehole.

Claim 7

A well logging system which comprises: a. a borehole tool having an acoustic transducer actuated acoustically to scan the circumference of the borehole repeatedly and to receive acoustic energy reflected from the walls of the borehole in timed relation to transmission dependent upon borehole diameter, b. means to generate a scalar function representative of the travel time of acoustic energy from said transducer to said wall and back to said transducer, and c. means to record said function separately for each of a plurality of vertical segments of said borehole wall where said segments are circumferentially displaced one from the other in relation to scan depth in said borehole.

Claim 8

The system of claim 5 Wherein control means enables said logging tool a plurality of short time spaced segments of each of said scans and wherein the recording means includes a plurality of amplitude-depth trace recorders each of which produces a record of each said time functions.

Claim 9

In a well logging system where an acoustic transducer in a logging tool acoustically scans the circumference of the borehole by repeatedly transmitting an acoustic pulse and receiving acoustic energy reflected from the walls of the borehole in timed relation to pulse transmission dependent upon borehole diameter, the improvement which comprises: a. a plurality of pulse transit time measuring means to generate scalar quantities representative of borehole diameter, b. control means to actuate said plurality of measuring means in a predetermined repetitive sequence, c. sync means to synchronize said control means to initiate each sequence in predetermined relation to a selected point in each scan cycle to limit said time interval measurement to a plurality of vertical segments of said borehole wall circumferentially displaced one from the other, and d. means for recording said scalar quantities separately for each of said segments as a function of depth of the scan level in said borehole.

Claim 10

In a well logging system where an acoustic transducer in a logging tool acoustically scans the circumference of the borehole by repeatedly transmitting an acoustic pulse and receiving acoustic energy reflected from the walls of the borehole in timed relation to pulse transmission dependent upon borehole diameter, the improvement which comprises: a. a plurality of pulse transit time measuring means to generate scalar quantities representative of borehole diameter, b. control means to actuate said plurality of measuring means in a predetermined repetitive sequence, c. sync means to synchronize said control means to initiate each sequence in predetermined relation to a selected point in each scan cycle to limit said time interval measurement to a plurality of vertical segments of said borehole wall circumferentially displaced one from the other, and d. means for recording said scalar quantities separately for each of said segments as a function of depth of the scan level in said borehole.

Claim 11

The system of claim 7 wherein said sync means includes an oscillator of a frequency of about four times the scan rate and wherein a sync pulse produced concomitantly with each scan cycle locks said oscillator and wherein counter means responsive to said oscillator output determine said sequence.

Claim 12

In a well logging system where an acoustic transducer in a logging tool acoustically scans the circumference of the borehole by repeatedly transmitting an acoustic pulse, receives acoustic energy reflected from the walls of the borehole in timed relation to pulse transmission dependent upon borehole diameter, and generates a voltage whose magnitude increases in a known relation to time following each said acoustic pulse, the improvement which comprises: a. a set of n sample and hold units each connected at one input to said generator means, b. control means responsive to said reflected energy and operable in relation to a selected point in each scan cycle and connected to second inputs of said n sample and hold units for actuation thereof in a predetermined repetitive sequence during each scan cycle for producing n output voltages representative of the diameter of n vertical segments along the wall of said borehole circumferentially displaced one from the other, and c. a set of n means for recording said scalar quantities separately for each of said segments as a function of depth of the scan level in said borehole.

Claim 13

In a well logging system where an acoustic transducer in a logging tool acoustically scans the circumference of the borehole by repeatedly transmitting an acoustic pulse, receives acoustic energy reflected from the walls of the borehole in timed relation to pulse transmission dependent upon borehole diameter, and generates a voltage whose magnitude increases in a known relation to time following each said acoustic pulse, the improvement which comprises: a. a set of n sample and hold units each connected at one input to said generator means, b. control means responsive to said reflected energy and operable in relation to a selected point in each scan cycle and connected to second inputs of said n sample and hold units for actuation thereof in a predetermined repetitive sequence during each scan cycle for producing n output voltages representative of the diameter of n vertical segments along the wall of said borehole circumferentially displaced one from the other, and c. a set of n means for recording said scalar quantities separately for each of said segments as a function of depth of the scan level in said borehole.

Claim 14

The system of claim 9 wherein said control means includes an oscillator of a frequency of slightly less than n times the scan rate and wherein a sync pulse produced concomitantly with each scan cycle locks said oscillator and wherein an n to 1 counter means responsive to said oscillator output determines said sequence.

Claim 15

The system of claim 10 where n 4 to produce a log of four quadrant spaced wall segments.

Claim 16

The system of claim 9 where n 4 to produce a log of four quadrant spaced wall segments.

Claim 17

A well logging system which comprises: a. a borehole tool having an acoustic transducer to scan the circumference of the borehole wall repeatedly and to receive reflected acoustic energy, b. means to generate a plurality of scalar functions representative of the travel time of acoustic energy from said transducer to said wall and back to said transducer, c. control means to limit said scalar functions to a limited angle in azimuth during each scan cycle corresponding to the width of a like plurality of vertical segments of said borehole wall circumferentially displaced one from the other, and d. means to record each scalar function separately.

Claim 18

A well logging system which comprises: a. a borehole tool having an acoustic transducer to scan the circumference of the borehole wall repeatedly and to receive reflected acoustic energy, b. means to generate a plurality of scalar functions representative of the travel time of acoustic energy from said transducer to said wall and back to said transducer, c. control means to limit said scalar functions to a limited angle in azimuth during each scan cycle corresponding to the width of a like plurality of vertical segments of said borehole wall circumferentially displaced one from the other, and d. means to record each scalar function separately.