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Collaborating Authors
Sensing and Signal Processing
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)
ABSTRACT 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 restimulation of preexisting 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 reopened. Secondary fractures deviate toward 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 45ยฐ angles from the fracture tip instead of the tensile stresses directly ahead of the tip. Antennas ahead of the fracture hits indicate the reopening of preexisting 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. The 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 > 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)
Use of Resistivity and Density Borehole Image Logs to Identify and Distribute Facies in the Pikka Unit - A Case Study from the Nanushuk Formation, North Slope, Alaska
Perona, Ricardo (Repsol USA) | Armitage, Dominic (Repsol USA) | Bonelli, James (Repsol USA) | Capuzzo, Nicola (Task Fronterra Geoscience) | Tingey, Brady (Task Fronterra Geoscience)
Over the past decade, the North Slope of Alaska has yielded several major hydrocarbon discoveries in deltaic topsets of the Brookian Nanushuk Formation. Together the Nanushuk topsets and genetically related foreset and bottomset beds of the Torok Formation comprise part of a giant clinothem system that prograded across the Colville Foreland Basin during the lower Cretaceous (Aptian through Cenomanian). The discovered Nanushuk topset play contains stratigraphically trapped hydrocarbons within multiple fairways trending roughly north to south along the basinยs extent. The Nanushuk topset play was first discovered in the Pikka Unit by Repsol and partners during the 2013 winter drilling campaign. The Pikka Unit is located at the eastern edge of the Nanushuk-Torok clinothem system and underlies the modern-day Colville River. Here, the Nanushuk Formation comprises shelf-edge deltaic and shoreface deposits, characterized by intercalations of fine-grained litharenites and silty mudstones. The layered character of the formation is readily recognized in electric logs due to density and resistivity contrasts between those main lithologies. Following the initial Pikka discovery, 14 appraisal wells were drilled in the unit, including 2 horizontal and 2 high angle wells. An extensive and diverse borehole image dataset was acquired and includes wireline high resolution oil-based mud resistivity and logging-while-drilling azimuthal density images. In addition, more than 1000 feet of continuous core was collected in three wells (Qugruk-8, Pikka B, Pikka B ST1). Borehole images were then used to orientate the high resolution CT scan images of the cores, which afterwards were integrated with the image log analysis. This study presents a case on how the integration of core sedimentology and detailed borehole image log analysis were used to guide and predict the facies distribution across the Pikka unit.
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.68)
- Geology > Sedimentary Geology > Depositional Environment > Transitional Environment > Deltaic Environment (0.54)
- Geophysics > Seismic Surveying > Borehole Seismic Surveying (1.00)
- Geophysics > Borehole Geophysics (1.00)
- North America > United States > Alaska > North Slope Basin > Umiat-Gubik Area > Torok Formation (0.99)
- North America > United States > Alaska > North Slope Basin > Prudhoe Bay Field (0.99)
- North America > United States > Alaska > North Slope Basin > Pikka Unit > Nanushuk Formation (0.99)
- (3 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Geologic modeling (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Borehole imaging and wellbore seismic (1.00)
The main objective of this work is to understand the impact of fracture, stress, drilling direction and other reservoir properties on the production performance in horizontal well (HW). Taking advantage of seventy available borehole image logs helped to extend analysis beyond individual wells to a field scale evaluation. Three analysis techniques were developed to progress with the study: Digital Interpretation of Borehole Breakout in image log, Favored Drilling Direction Map, and a Reservoir Property Filter to gauge well performance. Results in cross plots showed complicated, cloudy and multi-dimensional relationships. The findings will be used to guide future HW drilling optimization, support dynamic modeling and improve modelยs predictability for effective reservoir management.
- North America > United States (0.46)
- Asia > Kazakhstan > West Kazakhstan Region (0.29)
- Phanerozoic > Paleozoic > Permian (0.94)
- Phanerozoic > Paleozoic > Devonian (0.68)
- Geology > Structural Geology > Tectonics (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock (0.93)
- (2 more...)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Borehole Seismic Surveying (0.61)
- North America > United States > California > San Joaquin Basin > Lost Hills Field (0.99)
- North America > United States > California > Monterey Formation (0.99)
- Asia > Kazakhstan > West Kazakhstan > Uralsk Region > Precaspian Basin > Karachaganak Field (0.99)
- (5 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (0.93)
- (5 more...)
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)
- Information Technology > Sensing and Signal Processing (0.70)
- Information Technology > Communications > Networks > Sensor Networks (0.70)
In this study, we interpreted a cumulative 600m acoustic image log across the Triassic to Cambro-Ordovician interval in the Berkaoui oil field, Algeria. We interpreted 40 distinct breakout zones which have a combined length of 210m. These breakouts are aligned in the NNE-SSW direction indicating a mean maximum horizontal stress (SHmax) azimuth of 110ยฐN. The observed breakouts are ranked as ยA-Qualityย following the World Stress Map ranking guidelines. The angular width of each breakout has been inferred from the image log analysis and the same has been utilized to infer the SHmax gradient by stress polygon approach following the frictional faulting mechanism. The stress polygon across all the breakout intervals provides a practical Shmax range between 24.7-31.1 MPa/km, with an average gradient of ~ 27 MPa/km. Considering the Shmin range across the studied intervals, we infer a SHmax/Shmin ratio dominantly between 1.40-1.65, which is a much narrower and better-constrained range when compared to the previously published ranges from nearby fields with the same stratigraphy. The relative magnitudes of the in-situ stresses indicate a strike-slip faulting regime in the Berkaoui field. This study presents the utility of image log analysis and integration of breakout interpretation to obtain a more robust geomechanical model with reduced SHmax uncertainty.
- North America > United States (1.00)
- Asia (1.00)
- Africa > Middle East > Algeria > Illizi Province (0.28)
- Africa > Middle East > Algeria > Ouargla Province > Hassi Messaoud (0.28)
- Phanerozoic > Paleozoic > Ordovician (1.00)
- Phanerozoic > Mesozoic > Cretaceous > Upper Cretaceous (0.46)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.75)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.47)
- Geology > Structural Geology > Tectonics > Plate Tectonics (0.46)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Borehole Seismic Surveying (0.72)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Zubair Field > Zubair Formation (0.99)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Zubair Field > Mishrif Formation (0.99)
- Africa > Middle East > Egypt > Western Desert > Greater Western Dester Basin > Abu Gharadig Basin > Abu Gharadig Field (0.99)
- (10 more...)
_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 215454, โEnhancing Well-Control Safety With Dynamic Well-Control Cloud Solutions: Case Studies of Successful Deep Transient Tests in Southeast Asia,โ by M. Ashraf Abu Talib, SPE, M. Shahril Ahmad Kassim, and Izral Izarruddin Marzuki, SPE, Petronas, et al. The paper has not been peer reviewed. _ The complete paper addresses challenges related to well control and highlights the successful implementation of deep transient tests (DTT) in an offshore well performed with the help of a dynamic well-control simulation platform. The paper aims to provide insights into the prejob simulation process, which ensured a safer operation from a well-control perspective. Additionally, a comparison between simulated and actual sensor measurements during the DTT operation is presented. DTT DTT is a formation-testing (FT) method that allows pressure transient tests that reach deeper into the formation compared with conventional interval pressure transient tests (IPTT). DTT enables the testing of formations with higher permeability, greater thickness, and lower viscosity and real-time measurement of crucial parameters. During a DTT, formation fluid is pumped from the reservoir; upon stopping the pump, the formation pressure begins to recover as fluid further from the wellbore replaces the extracted fluid. By analyzing the resulting pressure transient, properties such as formation permeability, permeability anisotropy, and other characteristics can be determined. DTT allows for a better understanding of reservoir characteristics and rock heterogeneity. When properly designed and executed, DTT can reveal potential baffles and boundaries within the radius of investigation. A further advantage of DTT over drillstem tests (DST) is its minimal fluid flow, which allows for the attainment of objectives while contributing to the United Nations sustainable development goals. In DTT operations, the FT tool is connected to the drillpipe through a circulating sub and a slip joint. The circulating sub plays a critical role in DTT operations because it enables the continuous mixing of pumped formation fluid with circulated mud and facilitates its transportation to the surface (Fig. 1). Typically, a constant circulation rate ranging from 100 to 250 gal/min is maintained. During circulation, the annular preventer is closed and the mud/hydrocarbon mixture is directed through the choke line to the mud/gas separator (MGS) once it reaches the surface. No formation fluids are flared during DTT operations. Instead, the circulated oil is retained in the mud and only small amounts of gas are vented. By use of a slip joint, the FT remains anchored to the borehole wall. A high-resolution pressure gauge is used to capture and interpret even minor pressure fluctuations during the pressure transient buildup.
- Information Technology > Sensing and Signal Processing (1.00)
- Information Technology > Architecture > Real Time Systems (1.00)
- Information Technology > Cloud Computing (0.90)
The complete paper addresses challenges related to well control and highlights the successful implementation of deep transient tests (DTT) in an offshore well performed with the help of a dynamic well-control simulation platform. The paper aims to provide insights into the prejob simulation process, which ensured a safer operation from a well-control perspective. Additionally, a comparison between simulated and actual sensor measurements during the DTT operation is presented. DTT is a formation-testing (FT) method that allows pressure transient tests that reach deeper into the formation compared with conventional interval pressure transient tests (IPTT). DTT enables the testing of formations with higher permeability, greater thickness, and lower viscosity and real-time measurement of crucial parameters.
- Information Technology > Sensing and Signal Processing (1.00)
- Information Technology > Architecture > Real Time Systems (0.67)
Mission Earth: Geodynamics and Climate Change Observed Through Satellite Geodesy, by D. Angermann, R. Pail, F. Seitz, and U. Hugentobler, 2022.
- Europe > Greece (0.26)
- North America > Canada > British Columbia (0.16)
- Information Technology > Artificial Intelligence (0.52)
- Information Technology > Sensing and Signal Processing (0.39)