US 10,890,064 B2
Method and system for monitoring a material and/or a device in a bore hole using a fiber optic measuring cable
Thomas Reinsch, Berlin (DE); Santiago Ruben Aldaz Cifuentes, Potsdam (DE); Tobias Raab, Berlin (DE); Martin Lipus, Berlin (DE); Philippe Jousset, Berlin (DE); and Jan Henninges, Berlin (DE)
Assigned to HELMHOLTZ-ZENTRUM POTSDAM—DEUTSCHES GEOFORSCHUNGSZENTURM GFZ—STIFTUNG DES OFFENTLICHEN RECHTS DES LANDES BRADEN TELEGRAFENBERG, Potsdam (DE)
Filed by Helmholtz-Zentrum Potsdam—Deutsches GeoForschungsZentrum GFZ, Potsdam (DE)
Filed on Mar. 13, 2019, as Appl. No. 16/351,917.
Claims priority of application No. 10 2018 105 703 (DE), filed on Mar. 13, 2018.
Prior Publication US 2019/0284931 A1, Sep. 19, 2019
Int. Cl. E21B 47/005 (2012.01); E21B 47/16 (2006.01); E21B 47/18 (2012.01); G02B 6/44 (2006.01); E21B 47/113 (2012.01); E21B 47/135 (2012.01)
CPC E21B 47/16 (2013.01) [E21B 47/005 (2020.05); E21B 47/113 (2020.05); E21B 47/135 (2020.05); E21B 47/18 (2013.01); G02B 6/4463 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method for monitoring borehole integrity by monitoring a support material (3) introduced into the borehole and an introduced device using at least one fiber optic measurement cable (1), comprising:
a) introduction of the at least one fiber optic measurement cable (1) into the borehole, and connecting the measurement cable (1) by at least one of a physical connection or a mechanical connection to at least one of the support material (3) or to the introduced device to achieve the monitoring of support material (3) or the introduced device;
b) performance of at least one of relative vibration or strain measurements within the borehole, wherein, as measurement signal, a time series of a strain and a strain change of at least one area of the fiber optic measurement cable (1) is used for the determination of a strain and of a strain change of the support material (3) surrounding the fiber optic measurement cable (1) in this area and of the introduced device surrounding the fiber optic measurement cable (1) in this area;
c) analysis of at least one of strain amplitudes or of a strain amplitude distribution by time series comparisons for different areas and different times for the determination of an at least area-by-area spatially resolved and time resolved distribution of information on the state of the support material (3) and of the introduced device; characterized in that,
as distribution of information on the state, a distribution of the information on an acoustic impedance and on a mechanical coupling between support material (3), the introduced device and borehole surroundings are used, so that ambient noise amplitude is analyzed, which is defined by a superposition of acoustic impedance and mechanical coupling in order to determine areas in the borehole where an increased probability of the occurrence of material fatigue of the support material (3) and of the introduced device exists,
wherein
the information on at least one of the acoustic impedance and on a mechanical coupling is determined by comparison of measured strain amplitudes of different areas and times with a reference measurement, and
wherein the reference measurement comprises one or more measurements under known conditions and is also used as a calibration method.