Total field imaging probe

• US 5,255,245 A
• Filed: 01/28/1992
• Issued: 10/19/1993
• Est. Priority Date: 08/01/1989
• Status: Expired due to Fees

• Current Assignee: Andre Clot
• Original Assignee: Andre Clot
• Inventors: Clot, Andre
• Primary Examiner(s): Lobo, Ian J.
• Application Number:
  US07/828,912
• Time in Patent Office: 630 Days
• Field of Search: 367/25, 367/86, 367/911, 181/102, 181/104, 175/50, 166/250, 166/206, 166/179, 324/347, 324/323, 324/366, 73/152, 73/151
• US Class Current: 367/25
• CPC Class Codes: E21B 47/01 Devices for supporting measuring instruments on drill bits, pipes, rods or wirelines; Protecting measuring instruments in boreholes against heat, shock, pressure or the like
• CPC Class Codes: E21B 47/017 Protecting measuring instruments
• CPC Class Codes: G01V 11/005 Devices for positioning logging sondes with respect to the borehole wall centralising devices for drilling rods or pipes E21B17/10; setting or locking tools in boreholes E21B23/00; locating objects in boreholes E21B47/09
• CPC Class Codes: Y10S 367/911 Particular well-logging apparatus

Abstract

The invention relates to the principle of a probe to improve the quality of imaging logs in excavations, providing especially a good coverage of the wall 2 of the excavation by the beam of sensors 4 or electrodes. The basic component is constituted by a casing 6 moulded from a material of the elastomer type and made to allow it to be unfolded in the working position for the helically implanted zones of measurements 7, and applied against the wall 2.

The material of the zones 7 of measurements is selected as a function of the parameter to be measured, the immediate but non-limiting applications concerning microresistive and acoustic imaging.

The helical arrangement of the sensors 4 improves the coverage of the measurements with respect to conventional probes. Moreover, by eliminating the drilling mud 3 between the sensors 4 and the formation, this probe improves, in certain cases such as acoustic imaging for example, the response thereof and the quality of the measurements.

Claims

1. Total field imaging probe for effecting imaging logs over the whole periphery of the wall of a hole bored in the sub-soil and filled with a fluid said probe including sensors for measuring the characteristics of this soil mounted on or in the body of said probe, certain parts of said body being able to come into contact with said wall and, in the rest position, having an outer shape of a cylinder and a diameter smaller than the diameter of said hole, said body of the probe comprising:

at least one casing molded from a material of elastomer type, said casing comprising helical elements separated by bellows responsive to internal expansion means for unfolding said casing whereby said elements follow the shape of the wall of the well, said bellows ensuring the connections between the elements and maintaining the assembly of the casing in semi-rigid manner for following a peripheral surface continuity.

2. Total field imaging probe according to claim 1, wherein said casing is completely closed and contains a fluid which may be placed under pressure, in order to constitute said internal means for expanding the casing against the wall of the well, said helical elements being provided with appropriate elastic return systems for returning to a rest position in the absence of relative pressure of the fluid greater than that of ambient fluid and said bellows leave a sufficient passage for said fluid during the raising of the probe in the course of measurement.

3. Total field imaging probe according to claim 1, wherein said internal expansion means is constituted by any hydromechanical system connecting each helical element to a static structure element of the probe body.

4. Total field imaging probe according to claim 3, wherein the casing comprises a double wall, of which the space thus defined may be placed under pressure to ensure a greater rigidity.

5. Total field imaging probe according to claim 1, wherein at least certain f said sensors are known microresistive measurement electrodes integrated and moulded in said helical elements which may come into contact with said wall of the well, and disposed along these elements so that, whatever the diameter of the position of expansion and of measurement compatible with said probe, the whole of the periphery of the wall of said well is entirely covered and investigated by said electrodes, when said probe is raised without rotation.

6. Total field imaging probe according to claim 1, wherein at least one of said sensors is an ultrasonic transducer, located inside said probe, said casing being completely closed and filled with a fluid allowing a good acoustic coupling.

7. Total field imaging probe according to claim 6, wherein acoustic reflectors are placed in regular manner inside the elements of the probe for determining the geometry of the hole when said casing is rotating by measuring acoustic waves reflected from said reflectors to said acoustic sensor.

8. Probe according to claim 6, wherein acoustic reflectors are located at the intersection of half-bellows and oriented for directing lines perpendicular to the planes of these reflectors to pass through the acoustic sensor, the wave reflected by each of the reflectors enabling the geometry of the hole to be known.

9. Probe according to claim 1, wherein the material of the elements is transparent, said casing being completely closed and filled with a fluid allowing a good optical coupling, one of said sensors being a well camera which may allow observation even in the presence of opaque mud.

10. Total field imaging probe according to claim 1, wherein it is constituted by at least two casings placed one above the other and able to comprise elements and sensors of characteristics different from one another in order to be able to effect different types of measurement.