US2003132749A1PendingUtilityA1

Detecting tool motion effects on nuclear magnetic resonance measurements

49
Assignee: SCHLUMBERGER TECHNOLOGY CORPPriority: Jul 30, 1998Filed: Dec 5, 2002Published: Jul 17, 2003
Est. expiryJul 30, 2018(expired)· nominal 20-yr term from priority
Inventors:Peter SpeierMartin E. PoitzschSteven F. Crary
G01N 24/081G01V 3/32
49
PatentIndex Score
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Cited by
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Claims

Abstract

An NMR measurement apparatus is potentially subject to relative motion between the apparatus and a sample. The measurement apparatus includes at least one magnet, at least one coil and circuitry that is coupled to the magnet(s) and coil(s). The circuitry is adapted to use the magnet(s) and coil(s) to perform at least one NMR measurement and indicate the results of the NMR measurement(s). The results are then analyzed to determine an effect of the motion on the measurement(s).

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
         1 . A method usable with an NMR measurement apparatus, comprising: 
 performing a plurality of NMR measurements of a sample, at least two of the measurements having different sensitivities to a motion of the apparatus with respect to the sample; and    using the results of the measurements to determine an effect of the motion on at least one of the measurements.    
     
     
         2 . The method of  claim 1 , further comprising using the effect to interpret at least one of the measurements.  
     
     
         3 . The method of  claim 1 , further comprising using the effect to interpret at least one future measurement.  
     
     
         4 . The method of  claim 1 , further comprising using the effect to interpret at least one past measurement.  
     
     
         5 . The method of  claim 1 , further comprising using the effect to adjust a tool acquisition mode to compensate for the motion of the tool.  
     
     
         6 . The method of  claim 1 , further comprising using the effect to adjust measurement data to compensate for the motion of the tool.  
     
     
         7 . The method of  claim 1 , further comprising: 
 using a different static magnetic field to conduct one of the NMR measurements than another static magnetic field used to conduct another one of the NMR measurements.    
     
     
         8 . The method of  claim 7 , wherein said different magnetic field has a different field geometry than said another magnetic field.  
     
     
         9 . The method of  claim 7 , wherein said different magnetic field has a different gradient than said another magnetic field.  
     
     
         10 . The method of  claim 1 , further comprising: 
 radiating a first sequence of RF pulses to perform one of the measurements; and    radiating a second sequence RF pulses to perform another one of the measurements.    
     
     
         11 . The method of  claim 10 , wherein at least some of the pulses of the first sequence have a different magnitude than corresponding pulses of the second sequence.  
     
     
         12 . The method of  claim 10 , wherein at least some of the pulses of the first sequence have a different duration than corresponding pulses of the second sequence.  
     
     
         13 . The method of  claim 10 , wherein adjacent pulses of the first sequence are spaced further apart in time than corresponding adjacent pulses of the second sequence.  
     
     
         14 . The method of  claim 1 , further comprising: 
 using different types of pulse sequences to perform the measurements, the different types having different sensitivities to the motion.    
     
     
         15 . The method of  claim 1 , further comprising: 
 using a motion detection device to indicate the motion; and    further basing the determination of the effect on the indication from the motion detection device.    
     
     
         16 . The method of  claim 1 , wherein the using step comprises comparing measurements of a formation characteristic.  
     
     
         17 . The method of  claim 16 , wherein the characteristic comprises a porosity.  
     
     
         18 . The method of  claim 16 , wherein the characteristic comprises a bound fluid volume.  
     
     
         19 . A method usable with an NMR measurement apparatus, comprising: 
 performing a plurality of NMR measurements of a sample to measure spin-spin relaxation times of the sample and to measure spin-lattice relaxation times of the sample; and    using the results of the NMR measurements to determine at least an effect of the motion on the measurements.    
     
     
         20 . The method of  claim 19 , further comprising using the effect to interpret at least one of the measurements.  
     
     
         21 . The method of  claim 19 , further comprising using the effect to interpret at least one future measurement.  
     
     
         22 . The method of  claim 19 , further comprising: 
 using a motion detection device to indicate the motion; and    further basing the determination of the effect on the indication from the motion detection device.    
     
     
         23 . The method of  claim 19 , wherein the using step comprises comparing measurements of a formation characteristic.  
     
     
         24 . The method of  claim 23 , wherein the characteristic comprises a porosity.  
     
     
         25 . The method of  claim 19 , wherein the characteristic comprises a bound fluid volume.  
     
     
         26 . A method usable with an NMR measurement apparatus potentially subject to relative motion between the apparatus and a sample, the method comprising: 
 saturating spins in different regions;    performing a plurality of NMR measurements of a characteristic of the regions; and    using the measured characteristics to determine at least an effect of the motion on the measurements.    
     
     
         27 . The method of  claim 26 , further comprising using the effect to interpret at least one of the measurements.  
     
     
         28 . The method of  claim 26 , further comprising using the effect to interpret at least one future measurement.  
     
     
         29 . The method of  claim 26 , further comprising using the effect to interpret at least one past measurement.  
     
     
         30 . The method of  claim 26 , wherein one of the measurements comprises a T2-based measurement.  
     
     
         31 . The method of  claim 26 , further comprising: 
 using a motion detection device to indicate the motion; and    further basing the determination of the effect on the indication from the motion detection device.    
     
     
         32 . The method of  claim 26 , wherein the characteristics comprise initial amplitudes.  
     
     
         33 . The method of  claim 26 , wherein the characteristics comprise porosity indicators.  
     
     
         34 . A method usable with an NMR measurement apparatus, comprising: 
 performing an NMR measurement to produce spin echo signals from a sample; and    analyzing a characteristic of at least one of the echo signals to obtain an indication of relative motion between the NMR measurement apparatus and the sample.    
     
     
         35 . The method of  claim 34 , wherein the characteristic comprises an envelope shape of the signal.  
     
     
         36 . The method of  claim 34 , wherein the characteristic comprises a frequency content of the signal.  
     
     
         37 . The method of  claim 34 , wherein the act of analyzing comprises: 
 using a broadband filter to filter said at least one of the signals; and    using another filter matched to the expected shape of said at least one of the signals to filter said at least one of the signals.    
     
     
         38 . The method of  claim 34 , wherein the act of analyzing comprises: 
 using a filter adapted to provide an output signal that increases with magnitude as motion increases.    
     
     
         39 . The method of  claim 34 , wherein the act of analyzing comprises: 
 filtering said at least one spin echo signal using different filters that have different motion characteristics; and    using the results of the filtering to generate the indication.    
     
     
         40 . The method of  claim 39 , wherein the act of using comprises: 
 analyzing an absorptive component produced by one of the filters.    
     
     
         41 . The method of  claim 39 , wherein the act of using comprises: 
 analyzing a dispersive absorptive component produced by one of the filters.    
     
     
         42 . The method of  claim 34 , further comprising using the effect to interpret at least one of the measurements.  
     
     
         43 . The method of  claim 34 , further comprising using the effect to interpret at least one future measurement.  
     
     
         44 . The method of  claim 34 , further comprising using the effect to interpret at least one past measurement.  
     
     
         45 . The method of  claim 34 , further comprising: 
 using a motion detection device to indicate the motion; and    further basing the analysis on the indication from the motion detection device.    
     
     
         46 . The method of  claim 34 , wherein the step of using the results comprises computing magnitudes of the signals before stacking the magnitudes.  
     
     
         47 . The method of  claim 46 , wherein the step of stacking comprises stacking signals adjacent echo signals.  
     
     
         48 . The method of  claim 46 , wherein the step of stacking comprises stacking antisymmetric magnitudes of the signals.  
     
     
         49 . A method usable with an NMR measurement apparatus, comprising: 
 performing a plurality of NMR measurements in different regions of a sample; and    using the results of the measurements to determine at least an effect motion on at least one of the measurements.    
     
     
         50 . The method of  claim 49 , wherein the act of using comprises determining if the ratio of two of the measurements exceeds a predefined threshold.  
     
     
         51 . The method of  claim 49 , wherein the act of using comprises determining if the ratio of values of two of the measurements exceeds a predefined threshold.  
     
     
         52 . The method of  claim 49 , further comprising basing future measurements on the determination.  
     
     
         53 . The method of  claim 49 , wherein the act of basing future measurements on the determination comprises measuring a bound fluid volume using a fixed T2 cutoff if the motion effect permits a long echo train measurement.  
     
     
         54 . The method of  claim 49 , wherein the act of basing future measurements on the determination comprises measuring a bound fluid volume with a tapered T2 cutoff if the motion effect permits only a short echo train measurement.  
     
     
         55 . The method of  claim 49 , wherein the act of basing future measurements on the determination comprises measuring a bound fluid volume using a T1-based measurement if the motion effect permits only a short echo train measurement.  
     
     
         56 . The method of  claim 49 , further comprising: 
 using a motion detection device to indicate the motion; and    further basing the determination of the effect on the indication from the motion detection device.    
     
     
         57 . A method usable with an NMR measurement apparatus, comprising: 
 performing at least one NMR measurement of a sample; and    using said at least one NMR measurement to determine an effect of motion between the measurement apparatus and the sample.    
     
     
         58 . The method of  claim 57 , further comprising using the effect to interpret the measurement.  
     
     
         59 . The method of  claim 57 , further comprising using the effect to interpret at least one future measurement.  
     
     
         60 . The method of  claim 57 , further comprising using the effect to interpret at least one past measurement.  
     
     
         61 . The method of  claim 57 , further comprising: 
 using a motion detection device to indicate the motion; and    further basing the determination of the effect on the indication from the motion detection device.    
     
     
         62 . The method of  claim 57 , further comprising using the effect to adjust a tool acquisition mode to compensate for the motion of the tool.  
     
     
         63 . The method of  claim 57 , further comprising using the effect to adjust measurement data to compensate for the motion of the tool.  
     
     
         64 . The method of  claim 57 , wherein the using step comprises comparing measurements of a formation characteristic.  
     
     
         65 . The method of  claim 64 , wherein the characteristic comprises a porosity.  
     
     
         66 . The method of  claim 64 , wherein the characteristic comprises a bound fluid volume.  
     
     
         67 . An NMR measurement apparatus potentially subject to relative motion between the apparatus and a sample, comprising: 
 at least one magnet;    at least one coil; and    circuitry coupled to said at least one coil and adapted to use said at least one magnet and said at least one coil to: 
 perform a plurality of NMR measurements of the sample, at least two of the measurements having different sensitivities to a motion of the apparatus with respect to the sample, and  
 indicate the results of the measurements.  
   
     
     
         68 . The NMR measurement apparatus of  claim 67 , wherein said at least one magnet comprises: 
 a first permanent magnet adapted to establish a first magnetic field to conduct one of the measurements; and    a second permanent magnet adapted to establish a second magnetic field to conduct another one of the measurements.    
     
     
         69 . The NMR measurement apparatus of  claim 68 , wherein the first and second magnetic fields have different geometries.  
     
     
         70 . The NMR measurement apparatus of  claim 68 , wherein the first and second magnetic fields have different gradient patterns.  
     
     
         71 . The NMR measurement apparatus of  claim 68 , wherein the circuitry is further adapted to perform one of the measurements by radiating a first sequence of pulses and perform another one of the NMR measurements by radiating a second sequence of pulses.  
     
     
         72 . The NMR measurement apparatus of  claim 68 , wherein at least some of the pulses of the first sequence have a larger magnitude than corresponding pulses of the second sequence.  
     
     
         73 . The NMR measurement apparatus of  claim 68 , wherein adjacent pulses of the first sequence are spaced further apart in time than corresponding adjacent pulses of the second sequence.  
     
     
         74 . The NMR measurement apparatus of  claim 71 , wherein the first sequence has a greater sensitivity to the motion than the second sequence.  
     
     
         75 . An NMR measurement apparatus potentially subject to relative motion between the apparatus and a sample, comprising: 
 at least one magnet;    at least one coil; and    circuitry coupled to said at least one coil and adapted to use said at least one magnet and said at least one coil to: 
 perform a plurality of NMR measurements of a sample to measure spin-spin relaxation times and spin-lattice relaxation times of the sample, and  
 indicate the results of the first and second NMR measurements.  
   
     
     
         76 . An NMR measurement apparatus potentially subject to relative motion between the apparatus and a sample, comprising: 
 at least one magnet;    at least one coil; and    circuitry coupled to said at least one coil and adapted to use said at least one magnet and said at least one coil to: 
 perform a plurality of NMR measurements of characteristics of different regions, and  
 indicate the measured characteristics.  
   
     
     
         77 . The NMR measurement apparatus of  claim 76 , wherein at least one of the NMR measurements comprises a T2-based measurement.  
     
     
         78 . An NMR measurement apparatus potentially subject to relative motion between the apparatus and a sample, comprising: 
 at least one magnet;    at least one coil; and    circuitry coupled to said at least one coil and adapted to use said at least one magnet and said at least one coil to: 
 saturate spins present in different regions of the sample,  
 perform NMR measurements of characteristic of the regions, and indicate the measured characteristics.  
   
     
     
         79 . A method usable with an NMR measurement apparatus, comprising: 
 using at least one motion detection device to indicate an effect of motion of the NMR measurement apparatus on an NMR measurement that is performed by the NMR measurement apparatus; and    using the indication to correct the NMR measurement.    
     
     
         80 . The method of  claim 79 , wherein said at least one motion detection device comprises a magnetometer.  
     
     
         81 . The method of  claim 79 , wherein said at least one motion detection device comprises an accelerometer.  
     
     
         82 . The method of  claim 79 , wherein said at least one motion detection device comprises a strain gauge.  
     
     
         83 . The method of  claim 79 , wherein said at least one motion detection device comprises an accelerometer and a magnetometer.  
     
     
         84 . The method of  claim 79 , wherein said at least one motion detection device comprises a strain gauge and a magnetometer.  
     
     
         85 . The method of  claim 79 , wherein the step of using comprises adjusting the measurement to compensate for the motion.

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