Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
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)
DAS microseismic reflection imaging for hydraulic fracture and fault lineament characterization
Ma, Yuanyuan (Rice University) | Ajo-Franklin, Jonathan (Rice University, Lawrence Berkeley National Laboratory) | Nayak, Avinash (Lawrence Berkeley National Laboratory) | Correa, Julia (Lawrence Berkeley National Laboratory) | Kerr, Erich (SM Energy)
This study presents a novel workflow designed for migrating reflected S-waves generated by microseismic events, as recorded by downhole Distributed Acoustic Sensing (DAS), to characterize hydraulic fractures in three dimensions. In contrast to existing fracture imaging techniques, which have encountered challenges in accurately representing fracture networks and often rely on simplified models, the proposed imaging technique does not assume that fractures are planar or in a pre-specified orientation. DAS seismic measurements benefit from the large aperture and dense spatial sampling enabled by the kilometers-long fiber and, therefore are able to capture a large number of strong reflections compared to traditional borehole geophones or accelerometers. We treat microseismic events as high-frequency sources and apply prestack Kirchhoff migration to each individual source after wavefield separation. Fracture imaging results for multiple selected events are then stacked to generate a 3D reflectivity volume, revealing subsurface fracture and fault networks in intricate detail. The high-resolution fracture images generated by the developed reflection migrating process illuminate the heart of the stimulated volume of the reservoir, a zone that is often challenging to access using conventional surface arrays or active sources. To validate the effectiveness of the proposed workflow, our study employs a dataset acquired during a multi-well project in the Eagle Ford Shale and Austin Chalk in South Texas. To assess the accuracy and reliability of the results, the reflection imaging output is integrated with both microseismicity distribution and strain measurements from low-frequency DAS for interpretation. The results of reflection imaging improve our understanding of fracture geometry including distal fractures that are away from the monitoring well, allow direct estimation of fracture height and length, and potentially signify the presence of pre-existing fluid-filled fault lineaments.
- North America > United States > Texas > West Gulf Coast Tertiary Basin > Eagle Ford Shale Formation (0.89)
- North America > United States > Texas > West Gulf Coast Tertiary Basin > Austin Chalk Formation (0.89)
- North America > United States > Texas > Sabinas - Rio Grande Basin > Eagle Ford Shale Formation (0.89)
- (9 more...)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Information Technology > Sensing and Signal Processing (1.00)
- Information Technology > Communications > Networks > Sensor Networks (0.66)
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)
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)
- Well Completion > Completion Installation and Operations > Perforating (1.00)
- 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 (0.85)
- Information Technology > Artificial Intelligence (0.69)
- Information Technology > Communications > Networks > Sensor Networks (0.61)
Strain field reconstruction from helical-winding fiber distributed acoustic sensing and its application in anisotropic elastic reverse time migration
Zhang, Lele (China University of Petroleum (Beijing), China University of Petroleum (Beijing)) | Zhao, Yang (China University of Petroleum (Beijing), China University of Petroleum (Beijing)) | Liu, Lu (China University of Petroleum (Beijing)) | Niu, Fenglin (Rice University) | Wu, Wei (BGP INC.) | Wang, Chuangyang (China University of Petroleum (Beijing), China University of Petroleum (Beijing)) | Tang, Hengyu (Schlumberger) | Li, Jingming (China University of Petroleum-Beijing) | Zuo, Jiahui (China University of Petroleum (Beijing), China University of Petroleum (Beijing)) | Yao, Yi (Chinese Academy of Science) | Wang, Yixin (China University of Petroleum (Beijing))
Optical fiber-based distributed acoustic sensing (DAS) technology has been a popular seismic acquisition tool due to its easy deployment, wide bandwidth, and dense sampling. However, the sensitivity of straight optical fiber to only single-axis strain presents challenges in fully characterizing multi-components seismic wavefields, making it difficult to use these data in elastic reverse time migration (ERTM). The helical-winding fiber receives projecting signals projected onto the fiber from all seismic strain field components and has the potential to reconstruct those strain components for ERTM imaging. Here we give detailed mathematical principles of helical fiber-based DAS with crucial parameters such as pitch angle, gauge length and rotating angle. At least six points of DAS responses are required in one or several winding periods to rebuild the strain fields within the seismic wavelength. The projecting matrix of conventional regular helical-winding fiber is singular and ill-conditioned, which results in computation challenges for the inverse of the Hessian matrix for strain component reconstruction. To tackle this problem, we develop a non-regular variant-pitch angle winding configuration for helical fiber. Our winding design is validated using the rank and condition number of the projecting matrix, which is proven as an important tool in the reconstruction of the original seismic strains. The recovered strain components from the DAS response are then used to backward propagate receiver wavefields in ERTM with an efficient P/S decoupled approach. To sum up, we develop a novel winding design of helical fiber to recover the strain fields, and then propose an efficient 3D anisotropic P/S wave-mode decomposition method for generating vector P- and S-wavefields during their propagation. Both methods are applied to build an anisotropic DAS-ERTM workflow for producing PP- and PS- images. Two synthetic examples demonstrate the effectiveness of our approach.
- Asia (0.68)
- North America > United States > Texas (0.45)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring (1.00)
- Information Technology > Sensing and Signal Processing (0.70)
- Information Technology > Communications > Networks > Sensor Networks (0.70)
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)
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)
Claes Nicolai Borresen, Rune Tenghamn, and the late Svein Vaage are renowned for their roles in developing dual-sensor cable technology. They perfected the principles of dual-cable data acquisition in their roles as vice presidents and principal research geophysicists at Petroleum Geo-Services (PGS). They hold several patents dealing with the use of towed-pressure sensors and particle-motion sensors. Through their efforts, dual-sensor cable technology has been established as an important advance in marine seismic data acquisition. Innovation in the seismic industry is based on progress in sciences such as physics, mathematics, and information technology.
- Information Technology > Sensing and Signal Processing (1.00)
- Information Technology > Communications > Networks > Sensor Networks (1.00)