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Non-Traditional Resources
An Investigation on the Impact of Submicron-Sized Bubbles on the Fragmentation of Methane Clathrates Using Molecular Dynamics Simulation
Tesha, John Michael (State Key Laboratory of Separation Membranes and Membrane Processes, National Center for International Joint Research on Membrane Science and Technology, Tiangong University / School of Materials Science and Engineering, Tiangong University / Tanzania Bureau of Standards (Corresponding author)) | Dlamini, Derrick S. (Department of Civil & Environmental Engineering, University of California / California NanoSystems Institute, University of California) | Mapunda, Edgar Christian (Chemistry Department, University of Dar es salaam) | Kilewela, Ashura Katunzi (Tanzania Bureau of Standards)
Chemistry Department, University of Dar es salaam Summary The formation of submicron-sized bubbles is frequently associated with the fragmentation of methane clathrate. A bubble refers to a pocket or a round particle of one substance trapped inside another. In most cases, these spherical pockets are made of gas trapped inside of a liquid. Usually, bubbles can lie underneath the surface of the liquid until the surface tension breaks and the gas escapes back into the atmosphere. Therefore, understanding the fluid dynamics behavior of the clathrate phase shift and enhancing the production efficiency of natural gas requires knowledge of the impact of submicron-sized bubbles on the clathrate fragmentation. In this scenario, molecular dynamics simulation (MDS) models were carried out to investigate the methane clathrate fragmentation rate with and without preexisting submicron-sized bubbles. The findings demonstrate layer-by- layer fragmentation of the methane clathrate cluster in the liquid phase. Furthermore, this mechanism shows temperature and submicron-sized bubble existence independent of simulation settings or conditions. However, because of the stability of the supersaturated methane solution for a long period, methane clathrate fragmentation does not always result in the formation of submicron-sized bubbles. It was observed that between the bubble (submicron-size) of methane and the cluster surface of methane clathrate, there is a steep slope of methane concentration. Our discoveries in this research show that the existence of submicron-sized bubbles near the surface of the methane clathrate can speed up the rate of intrinsic decomposition while decreasing the activation energy of methane clathrate fragmentation. The mass flow rate is governed by the size of the submicron-sized bubbles and the spacing between the methane clathrate submicron-sized bubbles. Our results contribute to the in-depth knowledge of the fragmentation technique in the liquid phase for methane clathrates, which is critical in optimizing and designing effective gas clathrate development methods. Introduction Natural gas clathrate consists of natural gas compounds, primarily methane, entrapped in water molecules' crystalline matrix at high pressure and low temperature (Dinรงer and Zamfirescu 2014).
- Asia (1.00)
- North America > United States > Massachusetts (0.28)
- Africa > Tanzania > Dar es Salaam Region > Dar es Salaam (0.24)
- Reservoir Description and Dynamics > Reservoir Simulation (1.00)
- Reservoir Description and Dynamics > Non-Traditional Resources > Gas hydrates (1.00)
Trial-and-error modeling may provide some level of interpretation of the subsurface while sacrificing certainty, and certainty it is a viable alternative for precise three-dimensional (3D) interpretation of real ground-airborne frequency-domain electromagnetic (GAFEM) data. Therefore, a semiautomatic trial-and-error modeling approach has been presented in this study. We first developed a 3D GAFEM forward modeling code. Its accuracy was demonstrated using a 3D synthetic model with a topography and a tilted anomalous body. An initial model was established based on known geological constraints. The code was repeated, and the parameters of the model were renewed semi-automatically based on a predefined geometry-resistivity combination list. The model that could achieve the minimum error between the computed response and collected GAFEM data was selected as the final model. We applied the proposed semi-automatic trial-and-error modeling approach to a geothermal resource survey in the Yishu Faulting Basin, China. The purpose of this survey was to interpret the resistivity structure of the subsurface and evaluate the potential development of geothermal resources in the survey area. The final model obtained by trial-and-error modeling, which was constrained by known geological information and subsurface geoelectric structures inferred from 2D models inverted by the CSAMT and MT data measured at the same location, indicated the existence of geothermal resources. This indication was supported by drilling results from a well site located on the survey line. A comparative analysis was also conducted between the model obtained by trial-and-error modeling and the models obtained by 3D inversion of the GAFEM dataset. The apparent resistivity was calculated using the same data. The results have shown that different approaches can achieve similar subsurface geometries and resistivity distributions for faulting basin structures.
- Asia > China (0.61)
- North America > Canada > Newfoundland and Labrador > Newfoundland (0.28)
- Energy > Oil & Gas > Upstream (1.00)
- Energy > Renewable > Geothermal > Geothermal Resource (0.65)
- North America > Canada > Saskatchewan > Athabasca Basin (0.99)
- North America > Canada > Newfoundland and Labrador > Newfoundland > North Atlantic Ocean > Atlantic Margin Basin > Grand Banks Basin > Flemish Pass Basin (0.99)
- North America > Canada > Alberta > Athabasca Basin (0.99)
- Asia > China > Shandong > Yishu Basin (0.95)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Non-Traditional Resources > Geothermal resources (1.00)
- Information Technology > Software (0.67)
- Information Technology > Modeling & Simulation (0.66)
- Information Technology > Artificial Intelligence (0.46)
Detecting fractures and monitoring hydraulic fracturing processes at the first EGS Collab testbed using borehole DAS 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 (Lawrence Berkeley National Lab) | Rodriguez-Tribaldos, Vernica (Lawrence Berkeley National Lab) | Ajo-Franklin, Jonathan (Rice University) | Hopp, Chet (Lawrence Berkeley National Lab) | Johnson, Tim (Pacific Northwest National Laboratory) | Knox, Hunter (Pacific Northwest National Laboratory) | Blankenship, Doug (Sandia National Laboratories) | Dobson, Patrick (Lawrence Berkeley National Lab) | Kneafsey, Tim (Lawrence Berkeley National Lab) | Robertson, Michelle (Lawrence Berkeley National Lab)
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 conducts 10-m-scale field experiments of hydraulic fracture stimulation using 50-60 m deep experimental wells at the Sanford Underground Research Facility (SURF) in Lead, South Dakota. The first EGS Collab testbed is located at the 1616.67 m (4850 ft) depth at SURF and consists of one injection well, one production well, and six monitoring wells. All wells were drilled sub-horizontally 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 60-s time records of the borehole DAS ambient noise data and compute the noise root-mean-squares (RMS) amplitude on each channel (points along the fiber cable) to obtain DAS ambient noise RMS amplitude depth profiles along the monitoring wellbores. Our noise RMS amplitude profiles show 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 lithological changes shown 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 72 hours 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 (0.28)
- North America > United States > South Dakota (0.24)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Energy > Renewable > Geothermal > Geothermal Resource (0.86)
- Europe > Netherlands > German Basin (0.99)
- Europe > Germany > German Basin (0.99)
- Europe > Denmark > German Basin (0.99)
Africa's installed geothermal energy capacity is on track to surpass that of Europe by 2030, driven by a projected 35 billion in investment targeted at Kenyan and Ethiopian projects in the East African Rift through 2050, Rystad Energy reported in a recent analysis. Though Africa is home in 2023 to only about 1 GW of geothermal capacity--half of Europe's total--projects already announced will more than double the continent's total installed capacity over the next 7 years. Add in projects not yet announced, but vital to hitting government targets, and capacity could even triple by 2030, according to Rystad. Geothermal power entered Africa's energy mix in 1952 when the Democratic Republic of Congo (DRC) commissioned the Kiabukwa power plant. At the time, the DRC was the third country in the world to build a geothermal facility.
The purpose of hydraulic fracture modeling is to improve engineering decision-making. Success requires practical knowledge, engagement with real data, theoretical understanding, and critical thinking. The payoff is tremendous; design improvements routinely yield major uplifts in well performance and project economics. What types of papers push forward the state of the art for hydraulic fracturing modeling? In the pure development of models, practitioners adopt different philosophies. Some seek faster running models for quicker results. Others focus on integration of physics, trying to capture the essential elements of all key physical processes and how they interact. Still others focus on high-precision answers to narrower aspects of the problem. The appropriate emphasis depends on the context of how and why the model is being used. Many of the most influential papers of the past decade on hydraulic fracture modeling have not been modeling papers at all. Modeling depends on formulating a realistic conceptual model. New types of data collection and new ways of analyzing and interpreting data have given engineers a much clearer picture of what is happening in the subsurface. Extraordinary field-scale data-collection projects have given us calibration data that is not available from any other means. With a firmer foundation of knowledge, engineers can construct models that are not only precise but also, more importantly, accurate, and can apply them to solve practical problems. The work flowโhow modeling is integrated with field data, practical knowledge, and engineering decision-makingโis just as important as the model itself. Thus, papers that offer practical case studies are valuable because they demonstrate work flows and success stories that others can build upon. Hydraulic fracture modeling continues to be a vital contributor across a range of applications: shale, conventional reservoirs, and developing areas such as enhanced geothermal systems. Recommended additional reading at OnePetro: www.onepetro.org. SPE 212328 Interpretation of Fracture Initiation Points by In-Well Low-Frequency Distributed Acoustic Sensing in Horizontal Wells by Smith Leggett, Texas Tech University, et al. URTeC 3864951 Revealing the Production Drivers for Refracs in the Williston Basin by Alexander Cui, Novi Labs, et al. SPE 214784 Application of Hybrid Physics-Based and Data-Driven Fracture Propagation Modeling for Characterizing Hydraulic Fracture Geometry in Unconventional Reservoirs by K. Aldhayee, Texas A&M University, et al.
- North America > United States > South Dakota > Williston Basin (0.99)
- North America > United States > North Dakota > Williston Basin (0.99)
- North America > United States > Montana > Williston Basin (0.99)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Non-Traditional Resources > Geothermal resources (0.93)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (0.57)
The purpose of hydraulic fracture modeling is to improve engineering decision-making. Success requires practical knowledge, engagement with real data, theoretical understanding, and critical thinking. The payoff is tremendous; design improvements routinely yield major uplifts in well performance and project economics. What types of papers push forward the state of the art for hydraulic fracturing modeling? In the pure development of models, practitioners adopt different philosophies. Some seek faster running models for quicker results.
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Non-Traditional Resources > Geothermal resources (0.35)
Proof of Concept in a Full-Scale Field Test for the Novel Micro-Turbine Drilling Technology from a Cased Borehole in Granite Rock
Geissler, Niklas (Fraunhofer-Einrichtung fรผr Energieinfrastrukturen und Geothermie IEG / Fraunhofer-Chalmers Research Center for Industrial Mathematics (Corresponding author)) | Garsche, Florian (Fraunhofer-Einrichtung fรผr Energieinfrastrukturen und Geothermie IEG) | Samus, Vitalii (Fraunhofer-Einrichtung fรผr Energieinfrastrukturen und Geothermie IEG) | Polat, Berker (Fraunhofer-Einrichtung fรผr Energieinfrastrukturen und Geothermie IEG) | Di Mare, Francesca (Ruhr-Universitรคt Bochum) | Bracke, Rolf (Fraunhofer-Einrichtung fรผr Energieinfrastrukturen und Geothermie IEG)
Summary Exploration risks of geothermal projects are high, as required economic production rates are often not achieved. Stimulation methods from the oil and gas industry, such as radial jet drilling (RJD), which can be used to cost-effectively create flow paths around a main borehole, are usually not applicable in geothermal applications due to especially hard reservoir formations. Because of that, a novel technology called micro-turbine drilling (MTDยฎ) has been developed, which allows for the drilling of micro-sidetracks from cased boreholes even into very hard reservoir rock. The approach is based on the principles of the RJD operation. However, instead of a jetting nozzle, a microdrilling turbine is used to drive a bit that mechanically drills rock. This study presents the results of the proof of concept for MTD, which was conducted in the BedrettoLab in Switzerland at a depth of up to 1,053 ft (321 m) in granite rock.
- Geology > Geological Subdiscipline > Geomechanics (0.93)
- Geology > Rock Type > Igneous Rock > Granite (0.62)
ABSTRACT Accurate predictions of earthโs interior thermal conductivity are essential for interpreting the mechanisms involved in geothermal systems and delineating geothermal resource targets. Existing thermal conductivity prediction methods, which typically involve measurements of rock samples and predictions based on geophysical well logging, cannot accurately predict regional thermal conductivity distributions. We develop a 3D thermal conductivity prediction based on temperature field estimation. First, the finite-element method is used for temperature forward modeling. Subsequently, the inexact Gauss-Newton method is implemented in the prediction algorithm. Synthetic studies indicate that the method can recover the true model well. The subsurface temperature distribution of the Xiongโan New Area is predicted using the coefficient correction method of the optimal temperature. Next, we obtain the 3D distribution of thermal conductivity of deep formation in the Xiongโan New Area with the predicted temperature field. The distribution of terrestrial heat flow also is estimated. In addition, the law of thermal accumulation of strata at different depths is analyzed, and the internal relation among resistivity, temperature, and thermal conductivity is studied. Thus, the 3D thermal conductivity prediction method provides the theoretical basis for interpreting mechanisms for the origin of geothermal systems and heat accumulation patterns. It could have significant utility for the analysis of geothermal fields and the sustainable development and use of geothermal resources.
- Geology > Rock Type > Sedimentary Rock (1.00)
- Geology > Geological Subdiscipline (1.00)
- Geology > Structural Geology > Tectonics > Plate Tectonics (0.67)
- Geophysics > Electromagnetic Surveying (1.00)
- Geophysics > Borehole Geophysics (0.88)
- 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)
3D inversion of multifrequency controlled-source electromagnetic data and its application to geothermal exploration in the Tianzhen region of the northern Datong Basin, China
Peng, Ronghua (China University of Geosciences, Hubei Subsurface Multi-scale Imaging Key Laboratory) | Zhou, Wenlong (China University of Geosciences) | Hu, Xiangyun (China University of Geosciences, Hubei Subsurface Multi-scale Imaging Key Laboratory) | Liao, Weiyang (China University of Geosciences) | Wei, Meihua (China University of Geosciences, Shanxi Geological Engineering Exploration Institute) | Zhang, Changsheng (China University of Geosciences, Shanxi Geological Engineering Exploration Institute)
ABSTRACT Owing to its sensitivity to hydrothermal alteration and geothermal fluids, the distribution of subsurface electrical conductivity provides critical information for characterizing geothermal systems. For geothermal exploration, the controlled-source electromagnetic (CSEM) technique provides a crucial tool to image the subsurface resistivity structures, especially in areas with strong cultural noise. Usually, land-based CSEM surveys are carried out with dozens of operating frequencies to enhance spatial resolution. However, the 3D inversion of multifrequency CSEM data using the commonly used direct solver is challenging with limited computational resources. In this study, we implement a practical inversion strategy for interpreting 3D multifrequency CSEM data. By combining a hybrid direct-iterative solver with the inexact Gauss-Newton optimization, 3D inversion of CSEM data involving multiple frequencies can be performed effectively on typical workstations. First, we test the effectiveness of the developed approach using synthetic multifrequency 3D CSEM data generated for a simplified geothermal model. The inversion strategy is then applied to the multifrequency CSEM field data collected for the geothermal exploration at Tianzhen region in Shanxi Province, China. The comparison between the inversion results using the sparse data set (six frequencies) and the dense data set (12 frequencies) highlights the necessity of using data from more frequencies in the inversion to improve the resolution. The resulting 3D resistivity model clearly delineates the clay alteration layers and shallow thermal reservoirs of the potential high-temperature geothermal system within the study area, while its deep heat source is not revealed owing to the limited investigation depth of the survey.
- Geology > Geological Subdiscipline > Volcanology (0.68)
- Geology > Mineral (0.66)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Non-Traditional Resources > Geothermal resources (1.00)
A novel approach to address source overprint and shadow effects in controlled-source audio-frequency magnetotelluric exploration
Wang, Shengtao (Key Laboratory of Intraplate Volcanoes and Earthquakes (China University of Geosciences, Beijing), China University of Geosciences) | Lin, Changhong (Key Laboratory of Intraplate Volcanoes and Earthquakes (China University of Geosciences, Beijing), China University of Geosciences)
ABSTRACT Source overprint and shadow effects can significantly affect controlled-source audio-frequency magnetotelluric (CSAMT) data and mask subsurface geologic structures; however, few solutions have been presented. Based on the traditional observation approach, we develop a new approach to solve this problem. An additional transmitter and measurement zone are introduced in the novel approach to constrain the anomalous body causing source overprint or shadow effects in the inversion. To test this approach, six experimental models are designed. Three-dimensional CSAMT responses on the six synthetic models have been simulated, and the results indicate that source overprint and shadow effects have a strong influence on the data. Strong source overprint and shadow effects are found at low frequencies. The distribution of the source overprint or shadow distortions is affected by the shape of the anomalies below the transmitter or between the transmitter and receiver. We evaluate our approach by comparing the inversion results obtained with the new and traditional approaches based on the six synthetic data sets. The results indicate that the new approach not only effectively resolves the anomalies causing source overprint or shadow distortions but also yields more accurate target results in terms of resistivity value, structure geometry, and position than the conventional scheme. The inversion of field data from Yanqing, China, further verifies the effectiveness of our approach. Compared with the traditional inversion, the new scheme inversion obtains results that are more consistent with the rock type revealed by a drillhole.
- Overview (0.54)
- Research Report (0.46)
- Data Science & Engineering Analytics > Information Management and Systems (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (0.67)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Cross-well tomography (0.61)
- Reservoir Description and Dynamics > Non-Traditional Resources > Geothermal resources (0.46)