Detection of guided waves between gas wells for reservoir characterization

Geophysics ◽  
2002 ◽  
Vol 67 (1) ◽  
pp. 38-49 ◽  
Author(s):  
Jorge O. Parra ◽  
Chris L. Hackert ◽  
Anthony W. Gorody ◽  
Valeri Korneev
Keyword(s):  
Seismic Waves ◽  
Guided Waves ◽  
Reservoir Characterization ◽  
Real Data ◽  
Dispersion Analysis ◽  
Guided Wave ◽  
Low Velocity ◽  
Gas Field ◽  
Potential Applications ◽  
Southeast Texas

Guided seismic waves can be used to predict continuity and discontinuity of reservoir structures between wells, with the low‐velocity beds acting as waveguides. We relate guided‐wave signatures to waveguide targets using experimental data acquired at the Stratton gas field in southeast Texas. The observed seismic data indicate the presence of trapped energy in low velocity shale markers between wells 145 and 151. Guided waves in the form of leaky modes are excited, transmitted, and detected in the low‐velocity shale markers at a well separation of 1730 ft (527 m). Dispersion analysis, modeling, frequency–amplitude depth curves, well logs, and lithological information all support the results. Specifically, the characterization of two low‐velocity shale markers, V2 and V5, demonstrates that V2 is more heterogeneous than V5 between the source well 151 and detector well 145. Finally, images of synthetic and real data show the potential applications of the guided‐wave technology as a tool for reservoir characterization.

Transmission and detection of guided seismic waves in attenuating media

Geophysics ◽  
1998 ◽  
Vol 63 (4) ◽  
pp. 1190-1199 ◽  
Author(s):  
Jorge O. Parra ◽  
Brian J. Zook ◽  
Pei‐Cheng Xu ◽  
Raymon L. Brown
Keyword(s):  
Seismic Waves ◽  
Guided Waves ◽  
Test Site ◽  
Guided Wave ◽  
Leaky Mode ◽  
Head Wave ◽  
British Petroleum ◽  
Low Velocity ◽  
Time Frequency ◽  
Shaly Sandstone

We can use guided seismic waves to map properties of reservoirs between wells, with the low‐velocity layers acting as waveguides. When guided waves are detected, they are an indication of the continuity of the bed examined. Guided waveforms are characterized by time‐frequency representations to study important physical properties of the beds acting as waveguides. We used full waveform seismic modeling in viscoelastic media to examine the required velocity contrasts and distances over which guided‐wave signals can be used. In one set of models, sandstones are the central waveguide lithology; in another set, shales. We applied these models, referred to here collectively as shaly sandstone waveguides, to a range of geological circumstances where either the sands or the shales represent the low‐velocity layers within a reservoir. To study the distances over which guided waves can be detected, we compared the amplitudes of the signals computed for the models, using a realistic source strength, to the signal levels determined from published borehole noise studies. In shaly sandstone waveguides, we find it is feasible to use particle velocity measurements to record guided waves above seismic noise levels in the frequency range of 60 to 800 Hz at well separations exceeding a distance of 800 m. However, pressure detectors such as hydrophones may only be useful up to distances of 400 m between wells. In addition to the issues of shaly sandstone waveguides and practical distances between wells, we present an application of guided waves using crosswell seismic data from the Gypsy test site in Oklahoma (a site originally established by British Petroleum). In this field example within a sandstone reservoir, we demonstrate the sensitivity of leaky mode amplitudes to source‐receiver location. Another telltale characteristic of continuity in the type of reservoir studied at the Gypsy test site, where there is a low shear velocity contrast between the host medium and the waveguide, is the head wave followed by the leaky mode.

scholarly journals Numerical and Experimental Investigation of Guided Wave Propagation in a Multi-Wire Cable

2019 ◽  
Vol 9 (5) ◽  
pp. 1028 ◽  
Author(s):  
Pengfei Zhang ◽  
Zhifeng Tang ◽  
Fuzai Lv ◽  
Keji Yang
Keyword(s):  
Wave Energy ◽  
Guided Waves ◽  
Wave Structure ◽  
Excitation Power ◽  
Dispersion Analysis ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Mechanical Coupling ◽  
Guided Wave Propagation ◽  
Contact Acoustic Nonlinearity

Ultrasonic guided waves (UGWs) have attracted attention in the nondestructive testing and structural health monitoring (SHM) of multi-wire cables. They offer such advantages as a single measurement, wide coverage of the acoustic field, and long-range propagation ability. However, the mechanical coupling of multi-wire structures complicates the propagation behaviors of guided waves and signal interpretation. In this paper, UGW propagation in these waveguides is investigated theoretically, numerically, and experimentally from the perspective of dispersion and wave structure, contact acoustic nonlinearity (CAN), and wave energy transfer. Although the performance of all possible propagating wave modes in a multi-wire cable at different frequencies could be obtained by dispersion analysis, it is ineffective to analyze the frequency behaviors of the wave signals of a certain mode, which could be analyzed using the CAN effect. The CAN phenomenon of two mechanically coupled wires in contact was observed, which was demonstrated by numerical guided wave simulation and experiments. Additionally, the measured guided wave energy of wires located in different layers of an aluminum conductor steel-reinforced cable accords with the theoretical prediction. The model of wave energy distribution in different layers of a cable also could be used to optimize the excitation power of transducers and determine the effective monitoring range of SHM.

scholarly journals Assessment of low-velocity impact damage in composites by the measure of second-harmonic guided waves with the phase-reversal approach

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041988107 ◽  
Author(s):  
Weibin Li ◽  
Chang Jiang ◽  
Xinlin Qing ◽  
Liangbing Liu ◽  
Mingxi Deng
Keyword(s):  
Guided Waves ◽  
Second Harmonic ◽  
Impact Damage ◽  
Guided Wave ◽  
Second Order ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Phase Reversal ◽  
The Impact

Structural strength and integrity of composites can be considerably affected by the low-velocity impact damage due to the unique characteristics of composites, such as layering bonded by adhesive and the weakness to impact. For such damage, there is an urgent need to develop advanced nondestructive testing approaches. Despite the fact that the second harmonics could provide information sensitive to the structural health condition, the diminutive amplitude of the measured second-order harmonic guided wave still limits the applications of the second-harmonic generation–based nonlinear guided wave approach. Herein, laminated composites suffered from low-velocity impact are characterized by use of nonlinear guided waves. An enhancement in the signal-to-noise ratio for the measure of second harmonics is achieved by a phase-reversal method. Results obtained indicate a monotonic correlation between the impact-induced damage in composites and the relative acoustic nonlinear indicator of guided waves. The experimental finding in this study shows that the measure of second-order harmonic guided waves with a phase-reversal method can be a promising indicator to impact damage rendering in an improved and reliable manner.

Temperature Effects on Guided Wave Structural Damage Detection

2008 ◽  
Vol 47-50 ◽  
pp. 129-132 ◽  
Author(s):  
Chan Yik Park ◽  
Seung Moon Jun
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Guided Waves ◽  
Guided Wave ◽  
Low Velocity Impact ◽  
Structural Damage Detection ◽  
Low Velocity ◽  
Simple Method ◽  
Temperature Changes ◽  
Health Monitoring Systems

Guided wave structural damage detection is one of promising candidates for the future aircraft structural health monitoring systems. There are several advantages of guided wave based damage detection: well established theoretical studies, simple sensor devices, large sensing areas, good sensitivity, etc. However, guided wave approaches are still vulnerable to false warnings of detecting damage due to temperature changes of the structures. Therefore, one of main challenges is to find an effective way of compensating temperature changes and to imply it to existing damage detect algorithms. In this paper, a simple method for applying guided waves to the problem of detecting damage in the presence of temperature changes is presented. In order to examine the effectiveness of the presented method, delaminations due to low-velocity impact on composite plate specimens are detected. The results show that the presented approach is simple but useful for detecting structural damage under the temperature variations.

Seismic inversion of shale reservoir properties using microseismic-induced guided waves recorded by distributed acoustic sensing (DAS)

Geophysics ◽  
2021 ◽  
pp. 1-58
Author(s):  
Bin Luo ◽  
Ariel Lellouch ◽  
Ge Jin ◽  
Biondo Biondi ◽  
James Simmons
Keyword(s):  
Hydraulic Fracturing ◽  
Guided Waves ◽  
Wave Dispersion ◽  
Seismic Inversion ◽  
Dispersion Relations ◽  
Guided Wave ◽  
Low Velocity ◽  
Propagator Matrix ◽  
Shale Formation ◽  
Shale Reservoir

Shale formation properties are crucial for the hydrocarbon production performance of unconventional reservoirs. Microseismic-induced guided waves, which propagate within the low-velocity shale formation, are an ideal candidate for accurate estimation of the shale thickness, velocity, and anisotropy. A DAS fiber deployed along the horizontal section of a monitor well can provide a high-resolution recording of guided waves excited by microseismic events during hydraulic fracturing operations. These guided waves manifest a highly dispersive behavior that allows for seismic inversion of the shale formation properties. An adaptation of the propagator matrix method is presented to estimate guided wave dispersion curves and its accuracy is validated by comparison to 3-D elastic wavefield simulations. The propagator matrix formulation holds for cases of vertical transverse isotropy (VTI) as well. A sensitivity analysis of the theoretical dispersion relations of the guided waves shows that they are mostly influenced by the thickness and S-wave velocity of the low-velocity shale reservoir. The VTI parameters of the formation are also shown to have an impact on the dispersion relations. These physical insights provide the foundation for a dispersion-based model inversion for a 1-D depth-dependent structure of the reservoir and its surroundings. The inversion procedure is validated in a synthetic case and applied to the field records collected in an Eagle Ford hydraulic fracturing project. The inverted structure agrees well with a sonic log acquired several hundred meters away from the monitor well. Seismic inversion using guided wave dispersion therefore shows promise to become a novel and cost-effective strategy for in-situ estimation of reservoir structure and properties, which complements microseismic-based interpretation and production-related information.

Nonlinear process control of wave-equation inversion and its application in the detection of gas

Geophysics ◽  
2007 ◽  
Vol 72 (1) ◽  
pp. R9-R18 ◽  
Author(s):  
Yumei Shi ◽  
Wenzhi Zhao ◽  
Hong Cao
Keyword(s):  
Wave Equation ◽  
Seismic Waves ◽  
Computational Cost ◽  
Back Propagation ◽  
Real Data ◽  
Step Length ◽  
Western China ◽  
Preconditioned Conjugate Gradient ◽  
Model Parameters ◽  
Gas Field

The wave equation describes how seismic waves propagate in the subsurface. Inversion methods based on the wave equation naturally take into account the complex behavior of propagating waves and can be used to make accurate estimates of model parameters. However, computational cost and poor convergence have not been overcome, and thus restrict the broad application of this technique. Preconditioned conjugate gradient inversion using back-propagation techniques is a simple, robust implementation of wave-equation inversion in which the step length for correcting the model for each iteration is a crucial factor affecting convergence and hence computational cost. The step length can be calculated by an adaptive controller based on the theory of model reference nonlinear control that ensures that the error energy of the complex system vanishes rapidly. Although the computational cost for each iteration remains the same, the inversion is robust and converges more rapidly than other methods. We tested our method on synthetic data generated from a three-layer fractured model. The inversion converges to the true model after five iterations, and different initial models give similar inversion results. The application to 2D real data from a gas field in western China illustrates that even two iterations yield unambiguous interpretable inversion sections.

scholarly journals Single Versus Multi-channel Dispersion Analysis of Ultrasonic Guided Waves Propagating in Long Bones

2021 ◽  
pp. 016173462110066
Author(s):  
Tho N. H. T. Tran ◽  
Feng He ◽  
Zhenggang Zhang ◽  
Mauricio D. Sacchi ◽  
Dean Ta ◽  
...  
Keyword(s):  
Guided Waves ◽  
Single Channel ◽  
Dispersion Analysis ◽  
Guided Wave ◽  
Diagnostic Methods ◽  
Bovine Bone ◽  
Time Frequency ◽  
Advantages And Disadvantages ◽  
Frequency Map ◽  
Channel Dispersion

Ultrasonic guided wave techniques have been applied to characterize cortical bone for osteoporosis assessment. Compared with the current gold-standard X-ray-based diagnostic methods, ultrasound-based techniques pose some advantages such as compactness, low cost, lack of ionizing radiation, and their ability to detect the mechanical properties of the cortex. Axial transmission technique with a source-receiver offset is employed to acquire the ultrasound data. The dispersion characteristics of the guided waves in bones are normally analyzed in the transformed domains using the dispersion curves. The transformed domain can be time-frequency map using a single channel or wavenumber-frequency (or phase velocity-frequency) map with multi-channels. In terms of acquisition effort, the first method is more cost- and time-effective than the latter. However, it remains unclear whether single-channel dispersion analysis can provide as much quantitative guided-wave information as the multi-channel analysis. The objective of this study is to compare the two methods using numerically simulated and ex vivo data of a simple bovine bone plate and explore their advantages and disadvantages. Both single- and multi-channel signal processing approaches are implemented using sparsity-constrained optimization algorithms to reinforce the focusing power. While the single-channel data acquisition and processing are much faster than those of the multi-channel, modal identification and analysis of the multi-channel data are straightforward and more convincing.

An eigenfunction representation of deep waveguides with application to unconventional reservoirs

Geophysics ◽  
2021 ◽  
Vol 86 (6) ◽  
pp. T509-T521
Author(s):  
Owen Huff ◽  
Bin Luo ◽  
Ariel Lellouch ◽  
Ge Jin
Keyword(s):  
Finite Difference ◽  
Energy Distribution ◽  
Wave Energy ◽  
High Frequency ◽  
Guided Waves ◽  
Guided Wave ◽  
Low Velocity ◽  
Eagle Ford ◽  
Low Velocity Zone ◽  
Velocity Zone

Guided waves that propagate in deep low-velocity zones can be described using the displacement-stress eigenfunction theory. For a layered subsurface, these eigenfunctions provide a framework to calculate guided-wave properties at a fraction of the time required for fully numerical approaches for wave-equation modeling, such as the finite-difference approach. Using a 1D velocity model representing the low-velocity Eagle Ford Shale, an unconventional hydrocarbon reservoir, we verify the accuracy of the displacement eigenfunctions by comparing with finite-difference modeling. We use the amplitude portion of the Green’s function for source-receiver eigenfunction pairs as a proxy for expected guided-wave amplitude. These response functions are used to investigate the impact of the velocity contrast, reservoir thickness, and receiver depth on guided-wave amplitudes for discrete frequencies. We find that receivers located within the low-velocity zone record larger guided-wave amplitudes. This property may be used to infer the location of the recording array in relation to the low-velocity reservoir. We also study guided-wave energy distribution between the different layers of the Eagle Ford model and find that most of the high-frequency energy is confined to the low-velocity reservoir. We corroborate this measurement with field microseismic data recorded by distributed acoustic sensing fiber installed outside of the Eagle Ford. The data contain high-frequency body-wave energy, but the guided waves are confined to low frequencies because the recording array is outside the waveguide. We also study the energy distribution between the fundamental and first guided-wave modes as a function of the frequency and source depth and find a nodal point in the first mode for source depths originating in the middle of the low-velocity zone, which we validate with the same field data. The varying modal energy distribution can provide useful constraints for microseismic event depth estimation.

Validating the origin of microseismic events in target reservoir using guided waves recorded by DAS

2020 ◽  
Vol 39 (11) ◽  
pp. 776-784
Author(s):  
Owen Huff ◽  
Ariel Lellouch ◽  
Bin Luo ◽  
Ge Jin ◽  
Biondo Biondi
Keyword(s):  
Wave Energy ◽  
Guided Waves ◽  
Velocity Structure ◽  
Guided Wave ◽  
Accurate Estimation ◽  
Low Velocity ◽  
Eagle Ford ◽  
Low Velocity Layer ◽  
Microseismic Events ◽  
Velocity Layer

We develop a new algorithm that uses guided-wave energy in distributed acoustic sensing (DAS) records to identify microseismic events originating within or very close to a shale reservoir. Guided waves are dispersive waves that propagate in a low-velocity layer bounded by two high-velocity layers. This is a geologic structure that is seen for some shale reservoirs, most notably the Eagle Ford. Only microseismic events originating within or close to the low-velocity layer will excite significant guided-wave energy, which can be observed in DAS records. We confirm the relationship between guided-wave energy and event depth relative to the reservoir by using synthetic modeling. Given the known velocity structure, we can predict the dispersion curves for guided waves and use them to separate body and guided waves. We demonstrate a method to quantify the amplitude of guided waves in field DAS data recorded directly above the Eagle Ford Shale. Using this technique, we can separate events that originate within or close to the Eagle Ford from events that do not, thus circumventing the large depth uncertainty in a microseismic catalog derived from surface geophones. Our analysis shows that events classified as originating within or close to the Eagle Ford are horizontally closer to the stimulating well than non-Eagle Ford events. This is interpreted as representing different hydraulic fracture geometries in the Eagle Ford compared to its bounding formations, the Buda Limestone and Austin Chalk. The application of our method yields a new catalog that highlights the events relevant to stimulation and production in the target reservoir. It also provides a strong depth constraint that can improve relocation attempts using surface data, enabling a more accurate estimation of stimulated rock volume geometry.

scholarly journals Dispersion and Sensitivity Analysis of Quasi-Scholte Wave Liquid Sensing by Analytical Methods

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Onursal Önen
Keyword(s):  
Guided Waves ◽  
Dispersion Analysis ◽  
Guided Wave ◽  
Interface Waves ◽  
Ultrasonic Guided Wave ◽  
Scholte Waves ◽  
Liquid Boundary ◽  
Scholte Wave ◽  
Liquid Sensing ◽  
Solid Liquid

Ultrasonic-guided wave sensing relies on perturbation of wave propagation by changing physical properties of the target media. Solid waveguides, through which guided waves can be transduced between the transducer and the target media, are frequently employed for liquid sensing and several other applications. In this manuscript, liquid sensing sensitivity of dispersive quasi-Scholte waves, which are guided interface waves that travel at the solid-liquid boundary, is investigated. Dispersion analysis of quasi-Scholte waves is done and sensitivities of quasi-Scholte waves to changes in fluid density and speed of sound in a dipstick configuration are analyzed. An experimentally verified analytical model based on a global matrix approach is employed in a nondimensional manner to generate representative dispersion and sensitivity surfaces. Optimum configurations with respect to the material properties of the liquid and of the waveguide are illustrated, which would enable optimal quasi-Scholte liquid sensing.

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