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Collaborating Authors
Results
Distributed acoustic sensing for seismic surface wave data acquisition in an intertidal environment
Trafford, Andrew (University College Dublin) | Ellwood, Robert (Optasense Limited, QinetiQ) | Godfrey, Alastair (Optasense Limited, Indeximate Limited) | Minto, Christopher (Optasense Limited, Indeximate Limited) | Donohue, Shane (University College Dublin)
This paper assesses the use of Distributed Acoustic Sensing (DAS) for shallow marine seismic investigations, in particular the collection of seismic surface wave data, in an intertidal setting. The paper considers appropriate selection and directional sensitivity of fiber optic cables and validates the measured data with respect to conventional seismic data acquisition approaches ,using geophones and hydrophones, along with independent borehole and Seismic Cone Penetration Test (SCPT) data. In terms of cable selection, a reduction of amplitude and frequency response of an armored cable is observed, when compared to an unarmored cable. For seismic surface wave surveys in an offshore environment where the cable would need to withstand significant stresses, the use of the armored variant with limited loss in frequency response may be acceptable, from a practical perspective. The DAS approach has also shown good consistency with conventional means of surface wave data acquisition, and the inverted Vs is also very consistent with downhole SCPT data. Observed differences in phase velocity between high tide (Scholte wave propagation) and low tide (Rayleigh wave propagation) are not thought to be related to the particular type of interface wave due to shallow water depth. These differences are more likely to be related to the development of capillary forces in the partially saturated granular medium at low tide. Overall, this study demonstrates that the proposed novel approach of DAS using seabed fiber-optic cables in the intertidal environment is capable of rapidly providing near-surface shear wave velocity data across considerable spatial scales (multi-km) at high resolution, beneficial for the design of subsea cables routes and landfall locations. The associated reduction in deployment and survey duration, when compared to conventional approaches, is particularly important when working in the marine environment due to potentially short weather windows and expensive downtime.
- Europe (1.00)
- North America > United States > Illinois > Madison County (0.24)
- Research Report > New Finding (0.68)
- Research Report > Experimental Study (0.54)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Information Technology > Sensing and Signal Processing (1.00)
- Information Technology > Communications > Networks > Sensor Networks (0.85)
ABSTRACT Distributed acoustic sensing technology enables high-density seismic acquisition at a fraction of the cost. When deployed on the surface, surface distributed acoustic sensing (S-DAS) acquisition provides a cost-effective solution for dense high-resolution near-surface characterization through the analysis and inversion of surface waves. This is made possible by the relatively low cost of the fiber and the dense spatial sampling of the realized seismic data. The S-DAS data were collected during the acquisition of a 3D land large-scale field test and processed with a focus on recent advancements in the use of surface wave analysis and inversion. We compare and validate the result from the S-DAS recording with colocated multicomponent (3C) geophones and a conventional high-density surface seismic nodal acquisition. The comparison to 3C geophones demonstrated that for applications such as surface-wave inversion, S-DAS can outperform conventional geophones and shows consistency between electrical resistivity tomography and surface seismic inversion from S-DAS. In addition, continuous passive recording of environmental noise also offers a convenient alternative to active shooting allowing for surface wave inversion from reconstructed virtual shots.
- North America > United States > Texas > Permian Basin > Central Basin > Parker Field > Wolfcamp Formation (0.93)
- North America > United States > Texas > Permian Basin > Central Basin > Parker Field > Pennsylvanian Formation (0.93)
- North America > United States > Texas > Permian Basin > Central Basin > Parker Field > Cisco Formation (0.93)
- North America > United States > Texas > Permian Basin > Central Basin > Parker Field > Canyon Formation (0.93)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Information Technology > Sensing and Signal Processing (1.00)
- Information Technology > Communications > Networks > Sensor Networks (0.92)
ABSTRACT Over the past few decades, distributed acoustic sensing (DAS) data acquisition has seen great improvements from better interrogators, engineered fiber, and lessons learned from subsea installation and acquisition. This has given us confidence that DAS cables can be installed in wells with subsea trees to be used as receivers for vertical seismic profile (VSP) seismic imaging. VSP imaging for deepwater fields has been demonstrated to provide better illumination and higher-frequency seismic data. Permanent DAS cable installation can be used to acquire highly repeatable time-lapse (4D) data. DAS cables have been installed in a number of subsea wells on two deepwater oil fields with the intention of covering the crest of these fields with high-frequency seismic data. A system has been developed to allow for DAS acquisition on these offshore subsea wells with long-distance tie backs using permanently installed interrogators on the floating platforms and engineered fiber in the wells. On each of these fields, a DAS cable has now been installed, and subsequently, a zero offset (ZO) DAS VSP has been acquired for verification and commissioning. These ZO DAS VSP acquisitions indicate high-fidelity installations resulting in DAS VSP data with excellent data quality. These first subsea DAS acquisitions indicate great promise, and further installations and acquisitions are planned with the ultimate goal of providing high-frequency seismic images over the crest of these fields to reduce the uncertainty in decisions around reservoir management and future infill drilling.
- Europe (1.00)
- North America > United States > Gulf of Mexico > Central GOM (0.96)
- North America > United States > Texas (0.68)
- North America > United States > Gulf of Mexico > Central GOM > East Gulf Coast Tertiary Basin > Mississippi Canyon > Block 882 > Thunder Horse South Field (0.99)
- North America > United States > Gulf of Mexico > Central GOM > East Gulf Coast Tertiary Basin > Mississippi Canyon > Block 822 > Thunder Horse Field (0.99)
- North America > United States > Gulf of Mexico > Central GOM > East Gulf Coast Tertiary Basin > Mississippi Canyon > Block 778 > Thunder Horse South Field (0.99)
- (18 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Near-well and vertical seismic profiles (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Information Technology > Sensing and Signal Processing (0.85)
- Information Technology > Communications > Networks > Sensor Networks (0.61)
Protecting the weak signals in distributed acoustic sensing data processing using local orthogonalization: The FORGE data example
Obouรฉ, Yapo Abolรฉ Serge Innocent (Zhejiang University) | Chen, Yunfeng (Zhejiang University) | Fomel, Sergey (The University of Texas at Austin) | Chen, Yangkang (The University of Texas at Austin)
ABSTRACT The development of the distributed acoustic sensing (DAS) technique enables us to record seismic data at a significantly improved spatial sampling rate at meter scales, which offers new opportunities for high-resolution subsurface imaging. However, DAS recordings are often characterized by a low signal-to-noise ratio (S/N) due to the presence of data noise, significantly degrading the reliability of imaging and interpretation. Current DAS data noise reduction methods remain insufficient in simultaneously preserving weak signals and eliminating various types of noise. Particularly when dealing with DAS data that are contaminated by four types of noise (i.e.,ย high-frequency noise, high-amplitude erratic noise, horizontal noise, and random background noise), it becomes challenging to attenuate the strong noise while maintaining fine-scale features. To address these issues, we develop an integrated local orthogonalization (LO) method that can remove a mixture of different types of noise while protecting the useful signal. Our LO method effectively eliminates the aforementioned noise by concatenating multiple denoising operators including a band-pass filter, a structure-oriented, spatially varying median filter, a dip filter in the frequency-wavenumber domain, and a curvelet filter. Next, the local orthogonalization weighting operator is applied to extract signal energy from the removed noise section. We demonstrate the robustness of our LO method on various challenging DAS data sets from the Frontier Observatory for Research in Geothermal Energy geothermal field. The denoising results demonstrate that our LO method can successfully minimize the levels of different types of noise while preserving the energy of weak signals.
- Research Report > New Finding (0.66)
- Research Report > Experimental Study (0.48)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Information Technology > Artificial Intelligence (0.66)
- Information Technology > Sensing and Signal Processing (0.61)
- Information Technology > Communications > Networks > Sensor Networks (0.61)
- Information Technology > Data Science > Data Mining > Big Data (0.48)
Detecting fractures and monitoring hydraulic fracturing processes at the first enhanced geothermal system Collab testbed using borehole distributed acoustic sensing ambient noise
Li, David (Los Alamos National Laboratory) | Huang, Lianjie (Los Alamos National Laboratory) | Zheng, Yingcai (University of Houston) | Li, Yingping (University of Houston, BlueSkyDAS LLC) | Schoenball, Martin (GFZ German Research Center for Geosciences, Lawrence Berkeley National Lab) | Rodriguez-Tribaldos, Verรณnica (GFZ German Research Center for Geosciences, Lawrence Berkeley National Lab) | Ajo-Franklin, Jonathan (Rice University) | Hopp, Chet (GFZ German Research Center for Geosciences, Lawrence Berkeley National Lab) | Johnson, Tim (Pacific Northwest National Laboratory) | Knox, Hunter (Pacific Northwest National Laboratory) | Blankenship, Doug (Sandia National Laboratories) | Dobson, Patrick (GFZ German Research Center for Geosciences, Lawrence Berkeley National Lab) | Kneafsey, Tim (GFZ German Research Center for Geosciences, Lawrence Berkeley National Lab) | Robertson, Michelle (GFZ German Research Center for Geosciences, Lawrence Berkeley National Lab)
ABSTRACT Enhanced geothermal systems (EGS) require cost-effective monitoring of fracture networks. We validate the capability of using borehole distributed acoustic sensing (DAS) ambient noise for fracture monitoring using core photos and core logs. The EGS Collab project has conducted 10ย m scale field experiments of hydraulic fracture stimulation using 50โ60ย m deep experimental wells at the Sanford Underground Research Facility (SURF) in Lead, South Dakota. The first EGS Collab testbed is located at 1616.67ย m (4850ย ft) depth at SURF and consists of one injection well, one production well, and six monitoring wells. All wells are drilled subhorizontally from an access tunnel called a drift. The project uses a single continuous fiber-optic cable installed sequentially in the six monitoring wells to record DAS data for monitoring hydraulic fracturing during stimulation. We analyze 60ย s time records of the borehole DAS ambient noise data and compute the noise root-mean-square (rms) amplitude on each channel (points along the fiber cable) to obtain DAS ambient noise rms amplitude depth profiles along the monitoring wellbore. Our noise rms amplitude profiles indicate amplitude peaks at distinct depths. We compare the DAS noise rms amplitude profiles with borehole core photos and core logs and find that the DAS noise rms amplitude peaks correspond to the locations of fractures or lithologic changes indicated in the core photos or core logs. We then compute the hourly DAS noise rms amplitude profiles in two monitoring wells during three stimulation cycles in 72ย h and find that the DAS noise rms amplitude profiles vary with time, indicating the fracture opening/growth or closing during the hydraulic stimulation. Our results demonstrate that borehole DAS passive ambient noise can be used to detect fractures and monitor fracturing processes in EGS reservoirs.
- North America > United States > Texas (0.47)
- North America > United States > New Mexico (0.28)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Renewable > Geothermal > Geothermal Resource (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Energy > Renewable > Geothermal > Geothermal Resource for Power Generation > Enhanced Geothermal System (0.60)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Non-Traditional Resources > Geothermal resources (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Information Technology > Sensing and Signal Processing (0.71)
- Information Technology > Communications > Networks > Sensor Networks (0.71)
ABSTRACT The lack of knowledge of lateral heterogeneity in unconventional reservoirs commonly has negative impacts on drilling, completion efficiency, and production. However, current methods, such as well logging and seismic surveying, are limited in their ability to characterize unconventional reservoirs. We develop an alternative geophysical approach that uses distributed acoustic sensing (DAS) and perforation shots to characterize unconventional reservoirs. In our field data set, DAS-recorded perforation shots show strong P-wave signals. The recorded P-wave waveforms from the study area exhibit dispersive behavior, which can be clearly identified after signal processing. The spatial variations in phase velocity along the horizontal wellbore can be reliably measured by averaging the measurements from multiple closely situated perforation shots. We observe a low phase-velocity zone along the study well, which is spatially consistent with the well logs and root mean square amplitude extracted from the 3D seismic volume. The observed dispersive behavior of P waves is validated through numerical modeling. By comparing the results from the proposed method with those from modeling results and other measurements, we conclude that the proposed method results in a reasonable radius of investigation for unconventional reservoir characterization. The method also has the potential to infer hydraulic fracturing effectiveness by comparing the phase-velocity difference before and after stimulation. The data acquisition of the proposed workflow can be combined with perforation shot operations, which provides a cost-effective and suitable approach to investigating lateral heterogeneity in unconventional reservoirs.
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (1.00)
- Geophysics > Seismic Surveying > Passive Seismic Surveying > Microseismic Surveying (1.00)
- Geophysics > Seismic Surveying > Borehole Seismic Surveying > Vertical Seismic Profile (VSP) (0.68)
- Information Technology > Sensing and Signal Processing (0.85)
- Information Technology > Artificial Intelligence (0.69)
- Information Technology > Communications > Networks > Sensor Networks (0.61)
Lack of knowledge of lateral heterogeneity in unconventional reservoirs commonly imposes negative impacts on drilling, completion efficiency, and production. However, current methods, such as well logging and seismic survey, are limited in characterizing unconventional reservoirs. This study proposes an alternative geophysical approach that utilizes Distributed Acoustic Sensing (DAS) and perforation shot to characterize unconventional reservoirs. In our field dataset, DAS recorded perforation shot shows strong P-wave signals. The recorded P-wave waveforms from the study area exhibit dispersive behavior, which can be clearly identified after signal processing. The phase-velocity spatial variations along the horizontal wellbore can be reliably measured by averaging the measurements from multiple close-by perforation shots. We observe a low phase-velocity zone along the study well, which is spatially consistent with well logs and 3-D seismic images. The observed dispersive behavior of P waves is validated via numerical modeling. By comparing the proposed method with modeling results and other measurements, we conclude that the proposed method results in an ideal investigation radius for unconventional reservoir characterization. The method also has the potential to infer hydraulic fracturing effectiveness by comparing the phase-velocity difference before and after stimulation. The data acquisition of the proposed workflow can be combined with perforation shot operations, which provides a cost-effective and suitable approach to investigate lateral heterogeneity for unconventional reservoirs.
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (1.00)
- Geophysics > Seismic Surveying > Passive Seismic Surveying > Microseismic Surveying (1.00)
- Geophysics > Seismic Surveying > Borehole Seismic Surveying > Vertical Seismic Profile (VSP) (0.68)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Information Technology > Sensing and Signal Processing (0.84)
- Information Technology > Communications > Networks > Sensor Networks (0.70)
Quantitative Analysis of Hydraulic Fracturing Test Site 2 Completion Designs Using Crosswell Strain Measurement
Mjehovich, Joseph (IFDATA LLC (Corresponding author)) | Srinivasan, Aishwarya (Department of Petroleum Engineering, Texas A&M University) | Wang, Wen (IFDATA LLC) | Wu, Kan (Department of Petroleum Engineering, Texas A&M University) | Jin, Ge (Department of Geophysics, Colorado School of Mines)
Summary The implementation of effective completion design configurations during hydraulic stimulation is critical for the economic development of unconventional reservoirs. Low-frequency distributed acoustic sensing (LF-DAS)-based crosswell strain measurement is an advanced monitoring technique used to diagnose completion design efficiency but has been primarily restricted to qualitative analysis. In this study, we apply our novel Green-function based inversion algorithm to calculate fracture geometry (i.e., width) using the Department of Energy sponsored Hydraulic Fracturing Test Site 2 (HFTS-2) data set. The adopted algorithm relies on a 3D displacement discontinuity method to construct geomechanical models inverting linear elastic strain to hydraulic fracture widths. We use the inversion algorithm to calculate dynamic fracture widths using LF-DAS data recorded at two horizontal monitoring wells with permanent optical fiber installations. The inverted fracture widths at the monitoring wells from more than 100 hydraulic fracturing stages are used to diagnose the efficiency of eight unique completion designs implemented across three fracturing wells. We develop several metrics to evaluate completion design efficiency including the evenness of fracture widths at the monitoring wells, fracture density (i.e., number of fracture hits per foot), and fracture-width-density (i.e., fracture width/stage length). We observe a significant impact on completion efficiency with varying degrees of limited entry, tapered configurations, and stage length designs. Results indicate improved hydraulic stimulation is achieved with the implementation of limited-entry designs for extended stage lengths (ESLs), but no observable trend for normal stage lengths (NSLs). Tapered configurations significantly improve efficiency for ESLs but indicate little impact on normal-length designs. Reducing the space between perforation clusters (PCs) is determined to negatively impact design performance. Additionally, our quantitative analysis describes the impact of the nearby depletion zone on completion design efficiency. The methodology developed in this study provides operators with another level of quantitative information to optimize hydraulic fracturing treatments and reduce costs associated with the development of unconventional wells.
- North America > United States > Texas > Permian Basin > Delaware Basin (0.99)
- North America > United States > New Mexico > Permian Basin > Delaware Basin (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.94)
- North America > United States > New Mexico > Permian Basin > Wolfcamp Formation (0.94)
- Well Completion > Hydraulic Fracturing > Multistage fracturing (1.00)
- Well Completion > Completion Monitoring Systems/Intelligent Wells > Downhole sensors & control equipment (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Information Technology > Sensing and Signal Processing (0.88)
- Information Technology > Communications > Networks > Sensor Networks (0.67)
Distributed Acoustic Sensing (DAS) is a technology that enables continuous, real-time measurements along the entire length of a fiber optic cable. The low-frequency band of DAS can be used to analyze hydraulic fracture geometry and growth. In this study, the low-frequency strain waterfall plots with their corresponding pumping curves were analyzed to obtain information on fracture azimuth, propagation speed, number of fractures created in each stage, and re-stimulation of pre-existing fractures. We also use a simple geomechanical model to predict fracture growth rates while accounting for changes in treatment parameters. As expected, the hydraulic fractures principally propagate perpendicular to the treated well, that is, parallel to the direction of maximum horizontal stress. During many stages, multiple frac hits are visible indicating that multiple parallel fractures are created and/or re-opened. Secondary fractures deviate towards the heel of the well, likely due to the cumulative stress shadow caused by previous and current stages. The presence of heart-shaped tips reveals that some stress and/or material barrier is overcome by the hydraulic fracture. The lobes of the heart are best explained by the shear stresses at 45-degree angles from the fracture tip instead of the tensile stresses directly ahead of the tip. Antennas ahead of the fracture hits indicate the re-opening of pre-existing fractures. Tails in the waterfall plots provide information on the continued opening, closing, and interaction of the hydraulic fractures within the fracture domain and stage domain corridors. Analysis of the low-frequency DAS plots thus provides in-depth insights into the rock deformation and rock-fluid interaction processes occurring close to the observation well.
- North America > Canada > Alberta (1.00)
- North America > United States (0.67)
- North America > Canada > British Columbia > Western Canada Sedimentary Basin > Alberta Basin > Montney Formation Field > Montney Formation (0.99)
- North America > Canada > British Columbia > Western Canada Sedimentary Basin > Alberta Basin > Montney Formation (0.99)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Greater Peace River High Basin > Pouce Coupe Field (0.99)
- (2 more...)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Information Technology > Sensing and Signal Processing (1.00)
- Information Technology > Communications > Networks > Sensor Networks (0.70)
Summary Understanding gas dynamics in mud is essential for planning well control operations, improving the reliability of riser gas handling procedures, and optimizing drilling techniques, such as the pressurized mud cap drilling (PMCD) method. However, gas rise behavior in mud is not fully understood due to the inability to create an experimental setup that approximates gas migration at full-scale annular conditions. As a result, there is a discrepancy between the gas migration velocities observed in the field as compared to analytical estimates. This study bridges this gap by using distributed fiber-optic sensors (DFOS) for in-situ monitoring and analysis of gas dynamics in mud at the well scale. DFOS offers a paradigm shift for monitoring applications by providing real-time measurements along the entire length of the installed fiber at high spatial and temporal resolution. Thus, it can enable in-situ monitoring of the dynamic events in the entire wellbore, which may not be fully captured using discrete gauges. This study is the first well-scale investigation of gas migration dynamics in oil-based mud with solids, using optical fiber-based distributed acoustic sensing (DAS) and distributed temperature sensing (DTS). Four multiphase flow experiments conducted in a 5,163-ft-deep wellbore with oil-based mud and nitrogen at different gas injection rates and bottomhole pressure conditions are analyzed. The presence of solids in the mud increased the background noise in the acquired DFOS measurements, thereby necessitating the development and deployment of novel time- and frequency-domain signal processing techniques to clearly visualize the gas signature and minimize the background noise. Gas rise velocities estimated independently using DAS and DTS showed good agreement with the gas velocity estimated using downhole pressure gauges.
- North America > United States > Texas (0.68)
- Europe (0.68)
- Research Report > New Finding (1.00)
- Research Report > Experimental Study (0.93)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (0.51)
- Geophysics > Seismic Surveying > Passive Seismic Surveying (0.35)
- Information Technology > Sensing and Signal Processing (1.00)
- Information Technology > Architecture > Real Time Systems (1.00)
- Information Technology > Communications > Networks > Sensor Networks (0.86)