# US 10,371,851 B2 · Method for formation fracture characterization in highly inclined wells using multiaxial induction well logging instruments > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,851 B2 - Document ID: US10371851B2 - Status: Granted - Kind: B2 - Application number: 14/887,975 - Filed: 2015-10-20 - Published: 2016-10-13 - Granted: 2019-08-06 - Earliest claimed: 2014-10-21 - Assignees: Schlumberger Technology Corporation - Applicants: Schlumberger Technology Corporation - Inventors: Peter T. Wu; Samer Alatrach - Web page: https://patentgrep.com/patent/US10371851B2 ## CPC - G01V 3/28: using induction coils - E21B 47/00: Survey of boreholes or wells (monitoring pressure or flow of drilling fluid E21B21/08) - E21B 47/02: Determining slope or direction - E21B 47/18: through the well fluid {, e.g. mud pressure pulse telemetry} - E21B 49/00: Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells - G01V 3/18: specially adapted for well-logging - G01V 3/34: Transmitting data to recording or processing apparatus; Recording data - G01V 3/38: Processing data, e.g. for analysis, for interpretation, for correction - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract A method for characterizing fractures traversing a wellbore includes input to a computer multiaxial electromagnetic induction measurements corresponding to measurements made along two mutually orthogonal magnetic dipole moment axes perpendicular to an axis of the wellbore. The measurements correspond to at least one receiver spacing from a transmitter. The measurements represent induced voltage in a receiver having a same dipole moment direction as a dipole moment direction of a transmitter. A first derivative with respect to wellbore depth of the multiaxial electromagnetic induction measurements is calculated. At least one peak and an amplitude thereof of the first derivatives is calculated. The peak and the amplitude are used to determine a location and an aperture of at least one fracture traversing the wellbore. ## Claims ### Claim 1 A method for characterizing fractures traversing a wellbore, comprising: (a) accepting as input to a computer multiaxial electromagnetic induction measurements corresponding to measurements made along at least one of two mutually orthogonal magnetic dipole axes perpendicular to an axis of the wellbore, the measurements corresponding to at least one receiver spacing from a transmitter, the measurements representing induced voltage in a receiver having a same dipole moment direction as a dipole moment direction of a transmitter; (b) in the computer, calculating a first derivative with respect to wellbore depth of the multiaxial electromagnetic induction measurements; (c) in the computer determining at least one peak and an amplitude thereof of the first derivative; and (d) in the computer using the peak and the amplitude to determine a location and an aperture of at least one fracture traversing the wellbore by displaying the first derivative with respect to wellbore depth in the computer. ### Claim 2 (depends on 1) The method of claim 1 wherein two mutually orthogonal axes are rotated such that one thereof is in a vertical direction. ### Claim 3 (depends on 1) The method of claim 1 further comprising selecting a threshold value for amplitude and in the computer excluding from evaluation any peak in the first derivatives with respect to wellbore depth below the selected threshold value. ### Claim 4 (depends on 1) The method of claim 1 further comprising accepting as input to the computer multiaxial electromagnetic induction measurements at at least one additional receiver spacing from the transmitter and repeating (b), (c) and (d) for the at least one additional receiver spacing. ### Claim 5 (depends on 4) The method of claim 4 further comprising using (d) for at least one receiver spacing and (d) for at least one additional receiver spacing to determine a likelihood that the peak represents a true fracture. ### Claim 6 (depends on 1) The method of claim 1 further comprising in the computer displaying the input electromagnetic induction measurements in depth correspondence with the first derivatives thereof as a quality control indication. ### Claim 7 A system for fracture characterization, comprising: a processor and a display, the processor programmed to perform actions comprising; (a) accept as input to a computer multiaxial electromagnetic induction measurements corresponding to measurements made along two mutually orthogonal magnetic dipole axes perpendicular to an axis of the wellbore, the measurements corresponding to at least one receiver spacing from a transmitter, the measurements representing induced voltage in a receiver having a same dipole moment direction as a dipole moment direction of a transmitter, (b) calculating a first derivative with respect to wellbore depth of the multiaxial electromagnetic induction measurements, (c) determining at least one peak and an amplitude thereof of the first derivative, (d) using the peak and the amplitude to determine a location and an aperture of at least one fracture traversing the wellbore and; displaying the determined first derivatives with respect to wellbore depth on the display. ### Claim 8 (depends on 7) The system of claim 7 wherein two mutually orthogonal axes are rotated such that one thereof is in a vertical direction. ### Claim 9 (depends on 7) The system of claim 7 wherein the processor is further programmed to accept a selected threshold value for amplitude and to exclude from evaluation any peak in the first derivatives with respect to wellbore depth less than the selected threshold value. ### Claim 10 (depends on 7) The system of claim 7 wherein the processor is programmed accept as input multiaxial electromagnetic induction measurements at at least one additional receiver spacing from the transmitter and to repeat (b), (c) and (d) for at least one additional receiver spacing. ### Claim 11 (depends on 10) The system of claim 10 wherein the processor is further programmed to use (d) for at least one receiver spacing and to use (d) for at least one additional receiver spacing to determine a likelihood that the peak represents a true fracture. ### Claim 12 (depends on 7) The system of claim 7 wherein the processor is further programmed to display the input electromagnetic induction measurements in depth correspondence with the first derivatives thereof as a quality control indication. ### Claim 13 A method for well logging, comprising: (a) moving a multiaxial electromagnetic induction instrument along a wellbore drilled through subsurface formations; (b) energizing at least one multiaxial electromagnetic transmitter to impart an electromagnetic field in the subsurface formations along a plurality of magnetic dipole direction; (c) measuring induced voltage at at least one spaced apart position from the at least one multiaxial transmitter, the measuring resulting in signals corresponding to induced voltage along two mutually orthogonal magnetic dipole moment axes each perpendicular to a longitudinal axis of the wellbore; (d) calculating a first derivative with respect to wellbore depth of the induced voltages; (e) determining at least one peak and an amplitude thereof of the first derivatives; and (f) using the peak and the amplitude to determine a location and an aperture of at least one fracture traversing the wellbore by displaying the first derivative with respect to wellbore depth. ### Claim 14 (depends on 13) The method of claim 13 wherein two mutually orthogonal axes are rotated such that one thereof is in a vertical direction. ### Claim 15 (depends on 13) The method of claim 13 further comprising selecting a threshold value for amplitude and excluding from evaluation any peak in the first derivatives with respect to wellbore depth. ### Claim 16 (depends on 13) The method of claim 13 further comprising measuring induced voltages at at least one additional spaced apart position from the transmitter and repeating (c), (d), (e) and (f) for the at least one additional spaced apart position from the at least one multiaxial electromagnetic transmitter. ### Claim 17 (depends on 16) The method of claim 16 further comprising using (f) for at least one spaced apart position and (f) for the at least one additional spaced apart position to determine a likelihood that the peak represents a true fracture. ### Claim 18 (depends on 13) The method of claim 13 further comprising displaying the induced voltage measurements in depth correspondence with the first derivatives thereof as a quality control indication. ### Claim 19 (depends on 13) The method of claim 13 wherein the moving the well logging instrument comprises moving an electrical cable along the wellbore. ### Claim 20 (depends on 13) The method of claim 13 wherein the moving the well logging instrument comprises moving a drill string along the wellbore.