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We compare microseismic observations against pumping information, landing heights and various well logs. The data were acquired during cyclic-steam injection between September 2002 and December 2005. 95% of the microseismicity occurred during injection and in the overburden; 70% of the events happened during the first cycle. Microseismicity in the overburden is likely caused by its higher brittleness than in the reservoir, cluster of microseismic events in regions with a smaller landing height, thereby facilitating dry cracking due to the volumetric expansion of the reservoir. Yet, other areas with equally shallow landing heights displayed little to no microseismicity, pointing to an inhomogeneous steam front. Furthermore, recorded microseismicity is subject to the Kaiser effect in that event rates are low in subsequent cycles until the current injection pressure exceeds the previous maximum, explaining why 70% of the events occurred during the first cycle, and possibly why microseismicity during production accounted for only 5%. Microseismicity in brittle formations can be caused by pore-pressure variations (wet cracking) and/or changes in the total stresses (dry cracking). Identification of pore-pressure variations in the overburden is important since it may indicate containment challenges. Analysis of the growth rate of the microseismic cloud combined with the shallow landing height indicated dry cracking to be more likely than wet cracking but analysis of additional data is required to strengthen this conclusion.
- North America > Canada > Alberta (1.00)
- Europe (0.93)
- North America > Canada > British Columbia (0.67)
- Geology > Sedimentary Geology (1.00)
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Structural Geology > Tectonics > Plate Tectonics > Earthquake (0.46)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Thermal methods (1.00)
The proliferation and increasing sophistication of AI-assisted language tools (such as ChatGPT) have opened new avenues for research, but the ethics and best practices for their use are still evolving. These tools may generate useful information and content but are also prone to errors and inconsistencies. AI language tools may not be listed as an author. Any AI-generated content that is used within a manuscript should be thoroughly vetted, fact checked, and disclosed. If AI language tools are used within a manuscript, their use should be clearly explained within the methodology or acknowledgement section of the paper. If AI-generated content is included within a manuscript without an explanation, this can be grounds for rejection of the work at the discretion of SPE and may result in a code of conduct review.
Abstract Geophysical methods can provide valuable information when imaging man-made subsurface structures prior to archaeological excavations. An archaeological geophysical survey was conducted on funeral chambers (also known as kurgans) from the Early Bronze Age, in the Shadili-Uzun Rama Steppe of the Goranboy region, near the Kurakchay river gorge in Azerbaijan. This multimethod survey is based on a ground-penetrating radar profile, heat map of the total magnetic intensity, and contiguous profiles of electrical resistivity and seismic refraction. Brief processing and default inversion methods enabled us to obtain geophysical images in accordance with the lithology (a subsoil comprised of alluvial-proluvial conglomerate terrasse). The shape of the kurgans was recovered mainly through electrical resistivity tomography, enabling future targeted excavations. Overall, this study further testifies that geophysics provides valuable information for archaeological investigations, although higher resolution could be achieved by using more advanced field methodology and processing.
- Geology > Sedimentary Geology (0.46)
- Geology > Rock Type (0.34)
- Geophysics > Seismic Surveying (1.00)
- Geophysics > Magnetic Surveying (1.00)
- Geophysics > Electromagnetic Surveying (1.00)
Three-dimensional resistivity structure in Toya caldera region, Southwest Hokkaido, Japan — Constraints on magmatic and geothermal activities
Komori, Shogo (National Institute of Advanced Industrial Science and Technology (AIST)) | Takakura, Shinichi (National Institute of Advanced Industrial Science and Technology (AIST)) | Mitsuhata, Yuji (National Institute of Advanced Industrial Science and Technology (AIST)) | Yokota, Toshiyuki (National Institute of Advanced Industrial Science and Technology (AIST)) | Uchida, Toshihiro (National Institute of Advanced Industrial Science and Technology (AIST)) | Makino, Masahiko (National Institute of Advanced Industrial Science and Technology (AIST)) | Kato, Yosuke (Hanshin Consultants Co., Ltd.) | Yamamoto, Kazuya (Hanshin Consultants Co., Ltd.)
ABSTRACT Southwestern Hokkaido, Japan, is characterized by numerous Quaternary volcanoes and geothermal areas. At the same time, the region hosts various critical infrastructures, and there is a need to assess the impact of volcanic hazards on them. Geophysics could provide scientific clues for the hazard assessment by elucidating the abundance of subsurface magma. To clarify the resistivity structure from the crust to uppermost mantle of the Toya caldera, a representative Quaternary volcanic area, a wideband magnetotellurics survey of 117 points over land, sea, and lake areas, as well as 3D inversion, has been conducted. In combination with petrological and seismological findings, quantitative interpretation of the inverted model has found that conductive bodies in the uppermost mantle (14–68 ) suggest the presence of melts (0.25 vol%–3.4 vol%) or fluids (0.068 vol%–0.45 vol%). An extremely conductive body (<10 ) at a depth of approximately 3–14 km in the eastern geothermal area could be interpreted as a hydrothermal reservoir; below this body, the conductive column (1.8–15 ), rising from the uppermost mantle, suggests fluid upwelling. In contrast, high resistivity (>100 ) beneath Usu Volcano, the center of active volcanism, suggests that no mobile magma was present. A columnar-shaped region of slightly low resistivity (44 at minimum) is observed below the Toya caldera, which was inferred as cooling magma or an altered or heated upper crust attributed to past magma intrusion. A resistivity structure observed below the volcanic edifice is considered to reflect the steady state of the dormant volcanic system in this area, and there is likely no large amount of melt that would be deemed imminent for a caldera-forming eruption. This information could be a valuable scientific contribution to the volcanic hazard risk assessments currently being conducted in Japan.
- Geology > Geological Subdiscipline > Volcanology (1.00)
- Geology > Structural Geology > Tectonics > Plate Tectonics > Earthquake (0.46)
- Geophysics > Seismic Surveying (1.00)
- Geophysics > Electromagnetic Surveying (1.00)
- Energy > Renewable > Geothermal (1.00)
- Energy > Power Industry > Utilities > Nuclear (0.46)
ABSTRACT The S-wave velocity () is a vital parameter for various petrophysical, geophysical, and geomechanical applications in subsurface characterization. Nevertheless, obtaining shear sonic log is frequently challenging because of its high economic, time, and operating costs. Conventional methods for predicting rely on empirical relationships and rock-physics models, which often fall short in accuracy due to their inability to account for the complex factors influencing the relationship between and other parameters. We develop a physics-guided machine learning (ML) approach to predict the shear sonic log using various physical parameters (e.g., natural gamma ray, P-wave velocity, density, and resistivity) that can be readily obtained from standard logging suites. Three types of rock-physical constraints combined with three guidance strategies form the various physics-guided models. Specifically, the three constraint models include mudrock line, empirical P- and S-wave velocity relationship, and multiparameter regression from the logging data, and the three guidance strategies involve physics-guided pseudolabels, physics-guided loss function, and transfer learning. To assess the model’s generalization ability and simulate the lack of labeled data in real-world applications, a single well is used as a training well, whereas the remaining four wells are used to blind test in a clastic reservoir. Compared with supervised ML without any constraints, all models incorporating physical constraints demonstrate a significant improvement in prediction accuracy and generalization performance. This underscores the importance of integrating the first-order physical laws into the network training for shear sonic log prediction. The most successful approach combines the multiparameter regression relationship with the physics-guided pseudolabels in this case, resulting in a remarkable 47% reduction in the average root-mean-square error during the blind test.
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.36)
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling > Seismic Inversion (0.46)
- Europe > Norway > North Sea > Central North Sea > South Viking Graben > PL 046 > Block 15/9 > Volve Field > Shetland Group > Åsgard Formation (0.99)
- Europe > Norway > North Sea > Central North Sea > South Viking Graben > PL 046 > Block 15/9 > Volve Field > Shetland Group > Svarte Formation (0.99)
- Europe > Norway > North Sea > Central North Sea > South Viking Graben > PL 046 > Block 15/9 > Volve Field > Shetland Group > Sleipner Formation (0.99)
- (21 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Data Science & Engineering Analytics > Information Management and Systems > Artificial intelligence (1.00)
Effect of flow patterns and velocity field on oil-water two-phase flow rate in horizontal wells
Wu, Yuyan (Yangtze University, Yangtze University) | Guo, Haimin (Yangtze University, Yangtze University) | Deng, Rui (Yangtze University, Yangtze University) | Song, Hongwei (Yangtze University, Yangtze University)
ABSTRACT In a wellbore, any change in flow rate will result in a change in flow pattern and velocity. The flow pattern and velocity are the key parameters that determine the pressure gradient and liquid holdup. To study the effect of the flow pattern and velocity field on the flow rate of oil-water flow in horizontal wells, we apply the commercial software package ANSYS Fluent 2020 R2 to predict the flow patterns, water holdups, pressure gradients, flow rates, and velocity fields of horizontal wells. Trallero’s flow pattern chart and existing experimental data are used to verify the reliability of the model. We develop a simplified mathematical model of water holdup and compare it with existing models. This mathematical model may be limited to the range of fluid properties in the simulated method. The water holdup of the numerical simulation has a definite correlation with the experimental data. By comparing the numerical simulation results of the Nicolas model, the relationship between the slip velocity and water holdup is verified, and the reliability of the simulation results is verified. The simulation results demonstrate that the change in flow pattern is highly sensitive to the change in flow rate. When the flow pattern is stratified flow, the relative error of the simulated flow is small. When the flow pattern is dispersed flow, the relative error of the simulated flow is slightly larger. The oil is mainly concentrated in the high-velocity core area. At a higher total mixing velocity, the flow pattern is that of dispersed flow, with one phase uniformly mixed in the other phase. The simulation results have good qualitative and quantitative agreement with the experimental results.
Three-dimensional resistivity structure in Toya caldera region, Southwest Hokkaido, Japan — Constraints on magmatic and geothermal activities
Komori, Shogo (National Institute of Advanced Industrial Science and Technology (AIST)) | Takakura, Shinichi (National Institute of Advanced Industrial Science and Technology (AIST)) | Mitsuhata, Yuji (National Institute of Advanced Industrial Science and Technology (AIST)) | Yokota, Toshiyuki (National Institute of Advanced Industrial Science and Technology (AIST)) | Uchida, Toshihiro (National Institute of Advanced Industrial Science and Technology (AIST)) | Makino, Masahiko (National Institute of Advanced Industrial Science and Technology (AIST)) | Kato, Yosuke (Hanshin Consultants Co., Ltd.) | Yamamoto, Kazuya (Hanshin Consultants Co., Ltd.)
ABSTRACT Southwestern Hokkaido, Japan, is characterized by numerous Quaternary volcanoes and geothermal areas. At the same time, the region hosts various critical infrastructures, and there is a need to assess the impact of volcanic hazards on them. Geophysics could provide scientific clues for the hazard assessment by elucidating the abundance of subsurface magma. To clarify the resistivity structure from the crust to uppermost mantle of the Toya caldera, a representative Quaternary volcanic area, a wideband magnetotellurics survey of 117 points over land, sea, and lake areas, as well as 3D inversion, has been conducted. In combination with petrological and seismological findings, quantitative interpretation of the inverted model has found that conductive bodies in the uppermost mantle (14–68 ) suggest the presence of melts (0.25 vol%–3.4 vol%) or fluids (0.068 vol%–0.45 vol%). An extremely conductive body (<10 ) at a depth of approximately 3–14 km in the eastern geothermal area could be interpreted as a hydrothermal reservoir; below this body, the conductive column (1.8–15 ), rising from the uppermost mantle, suggests fluid upwelling. In contrast, high resistivity (>100 ) beneath Usu Volcano, the center of active volcanism, suggests that no mobile magma was present. A columnar-shaped region of slightly low resistivity (44 at minimum) is observed below the Toya caldera, which was inferred as cooling magma or an altered or heated upper crust attributed to past magma intrusion. A resistivity structure observed below the volcanic edifice is considered to reflect the steady state of the dormant volcanic system in this area, and there is likely no large amount of melt that would be deemed imminent for a caldera-forming eruption. This information could be a valuable scientific contribution to the volcanic hazard risk assessments currently being conducted in Japan.
- Geology > Geological Subdiscipline > Volcanology (1.00)
- Geology > Structural Geology > Tectonics > Plate Tectonics > Earthquake (0.46)
- Geophysics > Seismic Surveying (1.00)
- Geophysics > Electromagnetic Surveying (1.00)
- Energy > Renewable > Geothermal (1.00)
- Energy > Power Industry > Utilities > Nuclear (0.46)
A new nuclear magnetic resonance-based permeability model based on two pore structure characterization methods for complex pore structure rocks: Permeability assessment in Nanpu Sag, China
Xie, Weibiao (China University of Petroleum (Beijing) at Karamay, China University of Petroleum (Beijing)) | Yin, Qiuli (China University of Petroleum (Beijing) at Karamay) | Wu, Lifeng (China Petroleum logging Co., Ltd) | Yang, Fan (China Petroleum logging Co., Ltd) | Zhao, Jianbin (China Petroleum logging Co., Ltd) | Wang, Guiwen (China University of Petroleum (Beijing))
ABSTRACT The nuclear magnetic resonance (NMR) estimate of permeability is a fundamental method that has numerous applications in reservoir engineering and petrophysics. To improve the accuracy of the NMR-based permeability model, many variables are introduced into NMR-based permeability prediction models due to geometric complexity and pore structure heterogeneity. In this paper, two pore structure characterization methods are investigated based on the Kozeny-Carman model and equivalent component model. Furthermore, an NMR-based permeability model accounting for the effect of pore structure is developed based on the analysis of the relationship between two pore structure parameters, and it is applied to practically predict permeability. Results indicate that the new model-calculated permeability has good agreement with experimental data; moreover, the adaptability of the new NMR-based permeability prediction model is highly improved through reducing undetermined variables, and key parameters can be measured directly using NMR. The new model provides a valuable scientific resource and assists in the evaluation of hydrocarbon-bearing reservoirs with complex pore structure, such as tight sandstone, shale, and carbonate rock.
- Asia > China (1.00)
- Africa > Middle East > Egypt (0.46)
- Geology > Geological Subdiscipline (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.70)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.35)
- Asia > China > Xinjiang Uyghur Autonomous Region > Junggar Basin > Lucaogou Formation (0.99)
- Asia > China > Shandong > Gaoqing Field (0.99)
- Asia > China > Bohai Basin (0.99)
- Africa > Middle East > Egypt > Gulf of Suez > Gulf of Suez Basin > Kareem Formation > Shagar Member (0.99)
ABSTRACT Electrical resistivity tomography (ERT) is a widely used geophysical method for studying geologic hazards, civil engineering, and environmental remediation. It provides information about the subsurface’s resistivity distribution by analyzing electrical data collected at the surface or in boreholes. However, interpreting ERT images can be complex due to ambiguities in their resolution. To address this issue, we develop a postprocessing method called Python iMprovement of Electrical Resistivity tomography ReliabilitY (PyMERRY) to improve the reliability of ERT images. The PyMERRY code can be applied to any 2D resistivity model obtained from ERT inversion software. It computes a coverage mask that defines the domain well constrained by the data and the inversion process. It also evaluates the resistivity uncertainties in the ERT models. In addition to the sensitivity approaches, PyMERRY provides low- and high-resistivity values for all covered cells. Synthetic tests indicate that the approach is efficient and highlight the importance of resistivity contrasts, mesh selection, electrode spacing, and profile length in the reliability of ERT images. Compared with previous studies, using PyMERRY in south-central Bhutan allows a more accurate interpretation of ERT images. It confirms a high-resistivity contrast across the topographic frontal thrust and reveals the existence of small-scale variations.
- Geophysics > Electromagnetic Surveying (1.00)
- Geophysics > Borehole Geophysics (1.00)
Numerical simulation of fracture temperature field distribution during oil and gas reservoir hydraulic fracturing based on unsteady wellbore temperature field model
Meng, Lingdong (Northeast Petroleum University, FAPS Energy Technology Ltd, Key Laboratory of Oil & Gas Reservoir and Underground Gas Storage Integrity Evaluation of Heilongjiang) | Zhang, Xiaoling (Northeast Petroleum University, FAPS Energy Technology Ltd, Key Laboratory of Oil & Gas Reservoir and Underground Gas Storage Integrity Evaluation of Heilongjiang) | Jin, Yejun (Northeast Petroleum University, Key Laboratory of Oil & Gas Reservoir and Underground Gas Storage Integrity Evaluation of Heilongjiang) | Yan, Kun (Key Laboratory of Enhanced Oil Recovery (Northeast Petroleum University)) | Li, Song (Engineering Research Institute of PetroChina Southwest Oil and Gasfield Company)
ABSTRACT In the hydraulic fracturing oil and gas reservoir, the temperature variation of the fracturing fluid has a great impact on its flow and rheology, affecting the sand-carrying capacity and friction resistance of the fracturing fluid, and also affecting the settling speed of proppant in the fracture, thus changing the sand setting profile and sand laying concentration, and finally affecting the geometry of the fracture. Based on the energy balance and continuity equations, a numerical model for the distribution of wellbore temperature field in an extended-reach well is developed, and a variation law for the wellbore and reservoir temperature fields during fracturing also is formulated. A 3D mathematical model of the temperature distribution in hydraulic fracture and near-fracture formations has been developed based on heat transfer theory and finite-difference methods, taking into account the temperature gradients of fracture length and height according to the energy balance principle and fracture fluid continuity equations. The sensitivity factors of the temperature field are clarified, the wellbore temperature field and the fracture matrix temperature field model are coupled, and the influence rule of the temperature field change of the construction layer on the fracture shape while fracturing is revealed, which provides a theoretical basis for the hydraulic fracturing design optimization.
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.46)