Читать книгу Distributed Acoustic Sensing in Geophysics - Группа авторов - Страница 4

1 Chapter 1Figure 1.1 Operation principle of distributed acoustic sensing.Figure 1.2 COTDR.Figure 1.3 DAS schemas: MOD—intensity and frequency modulator; AOM—acousto‐o...Figure 1.4 DAS optical setup. Distance is proportional to flytime.Figure 1.5 COTDR response (Equation 1.6) shown in the left panel of the simu...Figure 1.6 Intensity changes are irregular along distance but harmonic along...Figure 1.7 Comparison of DAS theoretical response (Equation 1.13) with simul...Figure 1.8 Comparison of first and second order tracking algorithms for DAS....Figure 1.9 The left‐hand panel shows modeling of raw DAS acoustic data (Equa...Figure 1.10 Illustration of two time‐consecutive measurements when DAS outpu...Figure 1.11 Acoustic measurements using DAS: The left panel represents strai...Figure 1.12 Comparison of DAS spectral response with that from a 10 m sensor...Figure 1.13 Low spatial frequency gain in DAS by using long interferometer....Figure 1.14 DAS with linear optical cable is more sensitive to P‐wave in VSP...Figure 1.15 2D spectral representation on upgoing and downgoing acoustic wav...Figure 1.16 Normalized SNR curve (SNR vs. frequency) for a 3000 m/s wave spe...Figure 1.17 Sensing optical fiber cable deployments.Figure 1.18 The left‐hand panel shows a single shot of raw acoustic data; th...Figure 1.19 Comparison of DAS performance with SM and MM optical fiber.Figure 1.20 Directionality of DAS response: The left and central panels repr...Figure 1.21 3D VSP: Two intersecting images processed from DAS seismic data ...Figure 1.22 DAS hydraulic fracture monitoring in the treatment well with a f...Figure 1.23 DAS hydraulic fracture monitoring in the offset (a) with a fine ...Figure 1.24 DAS with standard fiber and engineered fiber with precision brig...Figure 1.25 Optical fiber with defined scatter center zones and the correspo...Figure 1.26 Acoustic measurements using DAS with precision engineered fiber:...Figure 1.27 Comparison of DAS with engineered fiber spectral response for sp...Figure 1.28 Ultimate SNR spectral response of DAS with standard and engineer...Figure 1.29 Displacement noise comparison of DAS (with and without engineere...Figure 1.30 Maximum strain comparison of first and second order algorithms f...Figure 1.31 Comparison of DAS with Rayleigh scattering [(a) and (b)] and eng...Figure 1.32 Comparison of DAS noise spectrums with Rayleigh scattering (a) a...Figure 1.33 Microseismic event in observation well detected by DAS with engi...Figure 1.34 Example of low frequency (down to millihertz level) “slow strain...Figure 1.35 Comparison of geophones (left panel) and DAS with engineered fib...

2 Chapter 2Figure 2.1 Options for acquiring DAS VSP data in a well.Figure 2.2 (Left) Conceptual diagram of an IU (inside the dotted black line)...Figure 2.3 (Top) Location of first spectral notch for a range of gauge lengt...Figure 2.4 Recommended pulse width as a function of gauge length.Figure 2.5 (Top) I (blue) and Q (orange) traces; (middle) corresponding rela...Figure 2.6 Strain rate VSP data collected with a vibrator – (top row) uncorr...Figure 2.7 (a) single sweep using Frequency 1 – note the prominent fading at...Figure 2.8 (Left) Strain rate record showing common‐mode noise; (right) same...Figure 2.9 Angular response of the fiber to P waves (left) and S waves (righ...Figure 2.10 Relationship among the various products created from a DAS data ...

3 Chapter 3Figure 3.1 Schematic principle of the fiber optic DAS system.Figure 3.2 Schematic of DMOF.Figure 3.3 Simulated intensity distribution along fiber when the intensity o...Figure 3.4 The block diagram of the continuous online DMOF fabrication syste...Figure 3.5 Comparison between the DMOF and the SMF: (a) Spectra of the backs...Figure 3.6 Working principle of DMOF‐DAS: (a) System configuration and (b) p...Figure 3.7 Sensing performance of the DMOF‐DAS system: (a) Photograph of the...Figure 3.8 Field test in the Fushan oil field: (a) Schematic of the zero‐off...Figure 3.9 Recorded seismic data in well using DMOF‐DAS: (a) DMOF‐DAS VSP da...

4 Chapter 4Figure 4.1 Principle of PGC‐DAS system with an unbalanced MI.Figure 4.2 Setup of PGC‐DAS system.Figure 4.3 Phase noise of PGC‐DAS system on Channel #4750: (a) Time series a...Figure 4.4 Intensity map of demodulation magnitude of each channel: (a) Wate...Figure 4.5 Time domain and STFT spectrogram of sweeping frequency signal.Figure 4.6 Amplitude response curve of PGC‐DAS system.Figure 4.7 Field trial of near‐surface seismic experiment. (a) Plan view of ...Figure 4.8 Initial data of DAS system and geophone array for x‐component at ...

5 Chapter 5Figure 5.1 (a) Map of the Lafarge‐Conco mine (presented with permission of L...Figure 5.2 (a) Sketch of a cross‐section showing the emplacement of co‐locat...Figure 5.3 Waveforms and spectra for different source locations recorded on ...Figure 5.4 Ambient noise records at Location E (left column) and Location H ...Figure 5.5 (a) Wavefield for all three cable loops for the source at Locatio...Figure 5.6 (a) Amplitude decay curves for Loop 1. Crosses show the amplitude...Figure 5.7 (a) Time vs. channel number plot for Loop 1 for the blast execute...Figure 5.8 (a) Stacked traces for Loop 1 for the ESS source at Location B. B...Figure 5.9 (a) Sample ray paths for surface wave tomography using the ESS so...Figure 5.10 (a) Example waveforms and first arrivals from channel pair 390 a...Figure 5.11 P‐wave differential travel‐time tomogram.

6 Chapter 6Figure 6.1 Absolute depth calibration using DAS receiver scalars (red and bl...Figure 6.2 Relative depth calibration between time‐lapse DAS VSP vintages (i...Figure 6.3 The impact (before/after) of relative depth calibration on 4D att...Figure 6.4 Ray contributions in deviated well – directionality consideration...Figure 6.5 3D/4D DAS VSP from flowing wells: (a) Geometry of 2017 simultaneo...Figure 6.6 Repeatability of DAS VSP images from flowing wells: (a) From Well...Figure 6.7 4D signals obtained from DAS VSP in Well W2 (2015–2017) compared ...

7 Chapter 7Figure 7.1 Three types of DAS‐VSP optical fiber deployment in a borehole. (a...Figure 7.2 DAS‐VSP data received by optical fibers freely suspended in the c...Figure 7.3 Comparison of VSP single‐shot record received from (a) flexible o...Figure 7.4 Diagram of cable resonance interference.Figure 7.5 The denoising effect of cable resonance. (a) Record before denois...Figure 7.6 DAS‐VSP recording before (a) and after (b) F‐X denoising.Figure 7.7 Before and after improved SNR processing common shot point gather...

8 Chapter 8Figure 8.1 Seismic acquisition systems in the Brady Hot Springs geothermal s...Figure 8.2 (a) Thirty seconds of raw data recorded by Channel 0100 in the so...Figure 8.3 The data preparation and modeling process used in this study.Figure 8.4 (a) Correlation coefficient to the reference trace vs. the number...Figure 8.5 Record section of NCFs between channel pairs along one segment (d...Figure 8.6 Individual NCFs (black) in a distance bin and the stacked trace (...Figure 8.7 Record section of NCFs between channel pairs along two in‐line se...Figure 8.8 (a) One MASW measurement example. The color represents stacking e...Figure 8.9 (a) One MFT measurement example. The color represents stacking en...Figure 8.10 (a) The layered model used in sensitivity kernel computation. (b...Figure 8.11 (a) Daily average surface temperature of 14 March 2016. (b) Shea...Figure 8.12 Velocity models at 20 m depth. (a) V_s model in this study, (b) V

9 Chapter 9Figure 9.1 We study surface waves (indicated by the red and blue bars) that ...Figure 9.2 Each polar plot shows the amplitude response of a measurement to ...Figure 9.3 The radius of each line represents the sensitivity of DAS with a ...Figure 9.4 The radius of each line represents the sensitivity of geophones (...Figure 9.5 The radius of each line represents the sensitivity of geophones (...Figure 9.6 The radius of each line represents the sensitivity of geophones (...Figure 9.7 The radius of each line represents the sensitivity of radial‐radi...Figure 9.8 We study the cross‐correlation response of two sensors at x₁ = (−...Figure 9.9 Random synthetic point sources emitting Rayleigh waves were recor...Figure 9.10 A single long radial‐radial cross‐correlation of synthetic geoph...Figure 9.11 Random synthetic point sources emitting Love waves were recorded...Figure 9.12 (Left) A single long transverse‐transverse cross‐correlation of ...Figure 9.13 (Left) A virtual source is marked in yellow along one fiber line...Figure 9.14 (Left) A virtual source is marked in yellow along one fiber line...

10 Chapter 10Figure 10.1 (Left) Trace of the array overlaid to an aerial photo of the cam...Figure 10.2 Map of the southwest region of the Stanford campus. It shows the...Figure 10.3 Data recorded for all the Felt Lake events shown in the same ord...Figure 10.4 Results of template matching for data recorded by SFSO ((a), JRS...Figure 10.5 Results of template matching for data recorded by SFSO (a), JRSC...Figure 10.6 (Left) Virtual source gathers computed by cross‐coherency applie...Figure 10.7 Cross correlations between data recorded by Channel #27 and (lef...Figure 10.8 Cross correlations between data recorded by Channel #27 and (lef...Figure 10.9 (Left) Frequency spectra of the data recorded by the ODH 3.1 int...Figure 10.10 The Alum Rock event recorded by the ODH 3.1 interrogator. (Left...Figure 10.11 The Alum Rock event recorded by the ODH 4.0 interrogator. (Left...Figure 10.12 (Left) The different types of identified wave‐mode clusters ave...Figure 10.13 Array geometry automatically estimated by combining a convoluti...

11 Chapter 11Figure 11.1 The MIP‐3H well trajectory. The lateral landed and stayed in the...Figure 11.2 Logs acquired along the lateral of the MIP‐3H well. Curves from ...Figure 11.3 Rose diagrams of natural fractures (a) observed along the length...Figure 11.4 Vertical CT scan of the MIP‐3H pilot core (7508–7509 feet). Vert...Figure 11.5 The incident laser is backscattered in different wavelength Rama...Figure 11.6 (a) Upper plot shows the measured DTS from May 2016 to May 2018 ...Figure 11.7 The detrended DTS attribute is averaged to the stage scale. The ...Figure 11.8 Energy attribute for Stage 5 (a) and Stage 10 (b) stimulation fr...Figure 11.9 Microseismic events’ distribution is illustrated for Stages 7–28...Figure 11.10 (a) A cluster score is calculated for each cluster for every st...

12 Chapter 12Figure 12.1 Comparison of spectrum of microseismic synthetic data for an eve...Figure 12.2 Comparison of spectrum of microseismic synthetic data. (Left) Pa...Figure 12.3 Event location and receiver array used in this study. Length uni...Figure 12.4 Workflow to generate the DAS synthetic waveforms in this study....Figure 12.5 An example of a synthetic waveform of DAS. The event is located ...Figure 12.6 (Left) High‐level design of migration‐based event location algor...Figure 12.7 Event locations estimated by CMM for data set only at the horizo...Figure 12.8 Event locations (purple) estimated by CMM with automatic receive...Figure 12.9 An example of a flag for receiver selection and model time picks...Figure 12.10 Comparison of event location with and without automatic receive...

13 Chapter 13Figure 13.1 The CO2CRC Otway Project site location and satellite image. The ...Figure 13.2 Seismic fold (color bar) given by a combination of seven wells (...Figure 13.3 DAS‐SOV VSP records acquired for SOV1 [(a) and (b)] and SOV 2 [(...Figure 13.4 Amplitude spectrum for the constellation fiber (blue curve) and ...Figure 13.5 VSP to CDP transform for the constellation fiber (a) and the sta...Figure 13.6 Crossline from a conventional vibroseis‐geophone surface seismic...Figure 13.7 VSP acquired with DAS using large and small motors at SOV1 [(a) ...Figure 13.8 Results of VSP to CDP transform for test with sweeps from 0 to 8...

14 Chapter 15Figure 15.1 An aerial photograph showing location of the study site and tran...Figure 15.2 Data characteristics along the dark fiber array. (a) A 10 s reco...Figure 15.3 (a) Comparison of spectral amplitude of the distinct noise signa...Figure 15.4 Ambient noise processing flow for V_s recovery at intermediate de...Figure 15.5 Comparison between a 30 minute single virtual shot gather and ph...Figure 15.6 Data sets and development of a reference V_s(z) model; panel (a) ...Figure 15.7 Results of multimodal inversion of the analyzed 1 km long virtua...

15 Chapter 16Figure 16.1 Map of the Garner Valley field site. The thick line is the layou...Figure 16.2 Subsurface geology at Garner Valley. (a) Shear‐wave velocity pro...Figure 16.3 (a) Mini‐Me structure. Locations of eccentric mass shaker and fo...Figure 16.4 Plots of 63 s of data for a colocated DAS channel 774 (top) and ...Figure 16.5 (a) Expanded plots of 13 s of data showing passing traffic for a...Figure 16.6 (a) Plot of 30 m of unfiltered DAS data. Channels are spaced 5 m...Figure 16.7 Plots (a) through (d) show source synchronous filtered MWCC DAS ...Figure 16.8 Dispersion curve results for the DAS and GVDA accelerometers num...Figure 16.9 Dispersion curve results from the DAS crosshatch line, as well a...Figure 16.10 (a) Modeled dispersion curve obtained by Stokoe et al. (2004) a...Figure 16.11 Dispersion curves obtained from the DAS long line active source...

16 Chapter 17Figure 17.1 Trend of collected journal and conference papers/abstracts relat...Figure 17.2 Histogram of papers presented at the SEG DAS workshops since 201...