System for measuring stress in downhole tubulars

Abstract

An apparatus for evaluating a tubular in a borehole of includes at least two electromagnetic acoustic transducers. The transducers are configured to generate and receive first and second acoustic waves in the tubular. A difference in velocity of the two acoustic waves is indicative of a stress field in the tubular.

1. An apparatus configured to evaluate a tubular within a borehole, the apparatus comprising:
 a plurality of acoustic transducers configured to generate and receive first and second acoustic waves in a body of the tubular, the second acoustic wave differing from the first acoustic wave in at least one of (A) a direction of propagation, and (B) a direction of polarizations; and 
 a processor configured to determine from a velocity of the first acoustic wave and a velocity of the second acoustic wave an indication of stress in the tubular, 
 wherein the first and second acoustic waves are generated at a substantially similar stress condition of the tubular. 
 
     
     
       2. The apparatus of  claim 1  wherein the acoustic transducers are selected from the group consisting of: (i) electro-magnetic acoustic transducers, (ii) piezoelectric transducers, and (iii) wedge transducers. 
     
     
       3. The apparatus  claim 1  wherein the plurality of acoustic transducers are disposed on at one least pad extendable from a body of a logging tool. 
     
     
       4. The apparatus of  claim 3  wherein the at least one pad comprises a plurality of pads. 
     
     
       5. The apparatus of  claim 1  wherein the first acoustic wave comprises a horizontally-polarized shear wave propagating in a first direction, and the second acoustic wave comprises a horizontally-polarized shear waves propagating in a direction substantially orthogonal to the first direction. 
     
     
       6. The apparatus of  claim 1  wherein the first acoustic wave comprises a horizontally polarized shear-wave and the second acoustic wave comprises a vertically polarized shear-wave propagating in a direction that is the same as a direction of propagation of the horizontal the polarized shear wave. 
     
     
       7. The apparatus of  claim 1  wherein the indication is related to at least one of (i) a torque, (ii) an axial stress, (iii) a bending load, (iv) a crushing load, (v) corrosion of the tubular, and (vi) a mechanical defect in the tubular. 
     
     
       8. The apparatus of  claim 2  further comprising a conveyance device configured for conveying the logging tool into the borehole, the conveyance device selected from (i) a wireline, (ii) a drilling tubular, (iii) a slickline, and (iv) coiled tubing. 
     
     
       9. The apparatus of  claim 1  wherein the tubular is selected from the group consisting of: (i) production tubing, (ii) casing, and (iii) a drilling tubular. 
     
     
       10. A method of evaluating a tubular within a borehole, the method comprising:
 propagating and receiving first and second acoustic waves in a body of the tubular, the second acoustic wave differing from the first acoustic wave in at least one of (A) a direction of propagation, and (B) a direction of polarizations; and 
 determining from a velocity of the first acoustic wave and a velocity of the second acoustic wave an indication of stress in the tubular; 
 wherein the first and second waves are propagated at a substantially similar stress condition of the tubular. 
 
     
     
       11. The method of  claim 10  further comprising generating the first acoustic wave and the second acoustic wave using a plurality of acoustic transducers disposed on at least pad extendable from a body of a logging tool. 
     
     
       12. The method of  claim 11  further comprising disposing the plurality of acoustic transducers on a plurality of pads. 
     
     
       13. The method of  claim 10  wherein the first acoustic wave and the second acoustic wave comprise horizontally-polarized shear waves propagating in substantially orthogonal directions. 
     
     
       14. The method of  claim 10  wherein the first acoustic wave comprises a horizontally polarized shear-wave and the second acoustic wave comprises a vertically polarized shear-wave propagating in a direction that is the same as a direction of propagation of the horizontal the polarized shear wave. 
     
     
       15. The method of  claim 10  wherein the indicator is related to at least one of (i) a torque, (ii) an axial stress, (iii) a bending load, (iv) a crushing load, (v) corrosion of the tubular, and (vi) a mechanical defect in the tubular. 
     
     
       16. The method of  claim 10  further comprising conveying the logging tool into the borehole using a conveyance device selected from (i) a wireline, (ii) a drilling tubular, (iii) a slickline, and (iv) coiled tubing. 
     
     
       17. The method of  claim 10  wherein the tubular is selected from the group consisting of: (i) production tubing, (ii) casing, and (iii) a drillstring. 
     
     
       18. A computer-readable medium product having stored thereon instructions that when read by a processor, cause the processor to perform a method, the method comprising:
 determining an indication of a stress field in a tubular from a velocity of a first acoustic wave and a velocity of second acoustic wave generated and received in a body of the tubular by a plurality of acoustic transducers, the second acoustic wave differing from the first acoustic wave in at least one of: (A) a direction of propagation, and (B) a direction of polarization; 
 wherein the first and second acoustic waves are generated at a substantially similar stress condition of the tubular. 
 
     
     
       19. The medium of  claim 18  further comprising at least one of (i) a ROM, (ii) an EPROM, (iii) an EEPROM, (iv) a flash memory, and (v) an optical disk. 
     
     
       20. A non-transitory computer-readable medium product having stored thereon instructions that when read by a processor, cause the processor to perform a method, the method comprising:
 propagating first and second acoustic waves in a body of a tubular, the second acoustic wave differing from the first acoustic wave in at least one of (A) a direction of propagation, and (B) a direction of polarizations; and   determining from a velocity of the first acoustic wave and a velocity of the second acoustic wave an indication of one of: (i) stress and (ii) a mechanical defect in the tubular;   
       wherein the first and second waves are propagated at a substantially similar stress condition of the tubular. 
     
     
       21. The non-transitory computer-readable medium product of claim 20 further comprising at least one of (i) a ROM, (ii) an EPROM, (iii) an EEPROM, (iv) a flash memory, and (v) an optical disk. 
     
     
       22. An apparatus configured to evaluate a tubular within a borehole, the apparatus comprising:
 a plurality of acoustic transducers configured to generate and receive first and second acoustic waves in a body of the tubular, the second acoustic wave differing from the first acoustic wave in at least one of (A) a direction of propagation, and (B) a direction of polarizations; and   a processor configured to determine from a velocity of the first acoustic wave and a velocity of the second acoustic wave an indication of one of: (i) stress and (ii) a mechanical defect in the tubular,   
       wherein the first and second acoustic waves are generated at a substantially similar stress condition of the tubular. 
     
     
       23. The apparatus of claim 22 wherein the acoustic transducers are selected from the group consisting of: (i) electro-magnetic acoustic transducers, (ii) piezoelectric transducers, and (iii) wedge transducers. 
     
     
       24. The apparatus claim 22 wherein the plurality of acoustic transducers are disposed on at least one pad extendable from a body of a logging tool. 
     
     
       25. The apparatus of claim 24 wherein the at least one pad comprises a plurality of pads. 
     
     
       26. The apparatus of claim 22 wherein the first acoustic wave comprises a horizontally-polarized shear wave propagating in a first direction, and the second acoustic wave comprises a horizontally-polarized shear wave propagating in a direction substantially orthogonal to the first direction. 
     
     
       27. The apparatus of claim 22 wherein the first acoustic wave comprises a horizontally polarized shear-wave and the second acoustic wave comprises a vertically polarized shear-wave propagating in a direction that is the same as a direction of propagation of the horizontally polarized shear wave. 
     
     
       28. The apparatus of claim 22 wherein the indication is related to at least one of (i) a torque, (ii) an axial stress, (iii) a bending load, (iv) a crushing load, (v) corrosion of the tubular, and (vi) a mechanical defect in the tubular. 
     
     
       29. The apparatus of claim 22 further comprising a conveyance device configured for conveying the logging tool into the borehole, the conveyance device selected from (i) a wireline, (ii) a drilling tubular, (iii) a slickline, and (iv) coiled tubing. 
     
     
       30. The apparatus of claim 22 wherein the tubular is selected from the group consisting of: (i) production tubing, (ii) casing, and (iii) a drilling tubular. 
     
     
       31. A method of evaluating a tubular within a borehole, the method comprising:
 propagating first and second acoustic waves in a body of the tubular, the second acoustic wave differing from the first acoustic wave in at least one of (A) a direction of propagation, and (B) a direction of polarization; and   determining from a velocity of the first acoustic wave and a velocity of the second acoustic wave an indication of one of: (i) stress and (ii) a mechanical defect in the tubular;   
       wherein the first and second waves are propagated at a substantially similar stress condition of the tubular. 
     
     
       32. The method of claim 31 further comprising generating the first acoustic wave and the second acoustic wave using a plurality of acoustic transducers disposed on at least one pad extendable from a body of a logging tool. 
     
     
       33. The method of claim 32 further comprising disposing the plurality of acoustic transducers on a plurality of pads. 
     
     
       34. The method of claim 31 wherein the first acoustic wave and the second acoustic wave comprise horizontally-polarized shear waves propagating in substantially orthogonal directions. 
     
     
       35. The method of claim 31 wherein the first acoustic wave comprises a horizontally polarized shear-wave and the second acoustic wave comprises a vertically polarized shear-wave propagating in a direction that is the same as a direction of propagation of the horizontally polarized shear wave. 
     
     
       36. The method of claim 31 wherein the indicator is related to at least one of (i) a torque, (ii) an axial stress, (iii) a bending load, (iv) a crushing load, (v) corrosion of the tubular, and (vi) a mechanical defect in the tubular. 
     
     
       37. The method of claim 31 further comprising conveying the logging tool into the borehole using a conveyance device selected from (i) a wireline, (ii) a drilling tubular, (iii) a slickline, and (iv) coiled tubing. 
     
     
       38. The method of claim 31 wherein the tubular is selected from the group consisting of: (i) production tubing, (ii) casing, and (iii) a drillstring.