Geomechanics for Energy and the Environment最新文献

{"title":"Study on the fracture propagation rule of simultaneous fracturing under cyclic injection","authors":"Ge Zhu ,&nbsp;Chuanli Wei ,&nbsp;Jingna Liu","doi":"10.1016/j.gete.2025.100711","DOIUrl":"10.1016/j.gete.2025.100711","url":null,"abstract":"<div><div>Simultaneous fracturing has emerged as a pivotal technology in unconventional oil and gas development, offering significant advantages in enhancing operational efficiency and reducing costs. However, plagued by stress shadow, non-uniform propagation of multiple fractures may occur during the operation, resulting in the stimulated reservoir volume (SRV) failing to meet the requirements. This study proposes an innovative scheme of utilizing cyclic injection to alleviate stress shadow. The dynamic stress generated by cyclic injection can complicate the interaction of multiple fractures during propagation, increasing the complexity of the fracture network. Furthermore, a numerical simulation model of multi-fracture propagation during simultaneous fracturing under cyclic injection was established using the extended finite element method (XFEM). The impact of the temporal modulation parameters governing cyclic injection scheme, including period, amplitude and phase, on the fracture propagation was discussed. Finally, an operational scheme was proposed in which different operating wells use distinct cyclic injection rates during simultaneous fracturing. The results reveal that cyclic injection scheme can significantly alleviate the fracture propagation disparities caused by stress shadow compared to conventional constant injection mode. The period, amplitude, and phase of cyclic injection rate exert critical control over fracture propagation morphology during simultaneous fracturing operations. Notably, the implementation of different cyclic injection schemes for various operating wells represents a deliberate attempt to alleviate stress shadow and improve fracture complexity. The research results can provide guidance for the field application of simultaneous fracturing and significantly contribute to improving the SRV.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100711"},"PeriodicalIF":3.3,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144563913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature- and Displacement-Dependent Model for unsaturated Earth pressures behind thermo-active retaining walls","authors":"Ahmad Rajabian,&nbsp;Farshid Vahedifard","doi":"10.1016/j.gete.2025.100712","DOIUrl":"10.1016/j.gete.2025.100712","url":null,"abstract":"<div><div>Earth pressures behind a thermo-active retaining wall can be influenced not only by the temperature-dependent response of the unsaturated backfill but also by the thermal expansion or contraction of the wall during the cooling and heating operations of a coupled heat pump. Such lateral deformations cause the unsaturated backfill to be placed in an intermediate passive or active state. In this study, an analytical framework is presented to compute the temperature- and displacement-dependent earth pressures of unsaturated soils behind embedded thermo-active retaining walls. The application of the proposed model is demonstrated by comparing its results with those from field-scale tests reported in the literature. A set of parametric studies is performed on a 6-m embedded thermo-active wall backfilled with three hypothetical soils (clay, silt, and sand) at 25 °C, 35 °C, and 45 °C. Further, unsaturated earth pressure profiles are generated for various thermally induced expansions and contractions during cooling and heating cycles. The results show that elevated temperatures decrease passive earth pressure and reduce the depth of tension cracks in at-rest and active states. Additionally, lateral wall expansion during the cooling cycle helps eliminate the tension zone. However, the heating cycle of the heat pump can be critical, as it leads to lateral contraction of the wall, thereby developing a tension-cracked zone, which can negatively affect the system’s efficacy. The presented framework is a useful tool for forensic studies as well as assessing the serviceability of embedded thermo-active retaining walls under working stress conditions by linking geotechnical and structural aspects.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100712"},"PeriodicalIF":3.3,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144595547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An integral approach using InSAR and data assimilation to disentangle and quantify multi-depth driven subsidence causes in the Ravenna coastland, Northern Italy","authors":"Manon Verberne ,&nbsp;Pietro Teatini ,&nbsp;Kay Koster ,&nbsp;Peter Fokker ,&nbsp;Claudia Zoccarato","doi":"10.1016/j.gete.2025.100710","DOIUrl":"10.1016/j.gete.2025.100710","url":null,"abstract":"<div><div>Land subsidence in the Ravenna area (Italy) was a hydrogeological hazard until the end of last century. Although subsidence reduced during the last decades, the area is still experiencing vertical displacements. Understanding their drivers is challenging. Land subsidence magnitude and distribution must be interpreted with a combination of geological factors and human activities. This study integrates various datasets, subsidence observations, and subsidence models to evaluate the contributions of three main causes: building related, shallow subsurface processes and deep subsurface processes. The model result was optimized using Interferometric Synthetic Aperture Radar. The highest subsidence rates, of over 10 mm/year, were found at locations where multiple causes have an effect. The results of building-related subsidence indicate that subsidence rates associated with industrial buildings are twice as high as for residential buildings. This difference is even more pronounced in lagoonal and reclaimed areas. Shallow causes, associated with overburden weight on tidal deposits and drainage of reclaimed land, cause significant subsidence along the coast. Deep causes, by offshore gas extraction, contribute to subsidence along parts of the coast, with a decreasing trend over time. Other factors, such as low-lying farmland drainage, (historical) groundwater extraction and compaction of Quaternary deposits are not specifically addressed because of their small contribution to the total subsidence during the time period considered. This study underscores the importance of a comprehensive approach that considers the interplay between geomorphology and geology, industrialization, urbanization, and fluid extraction. Geotechnical assessments and improved subsidence models, incorporating localized data on buildings and subsurface fluid withdrawals, are crucial for developing effective mitigation strategies.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100710"},"PeriodicalIF":3.3,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A data-driven and machine learning-assisted interpretation of hydraulic fracturing experiments in various formations","authors":"Charalampos Konstantinou ,&nbsp;Panos Papanastasiou","doi":"10.1016/j.gete.2025.100707","DOIUrl":"10.1016/j.gete.2025.100707","url":null,"abstract":"<div><div>Hydraulic fracturing has evolved from enhancing oil and gas recovery to addressing challenges in groundwater hydraulics and geo-environmental engineering. This study consolidates data from 30 experimental studies, including both high-permeability formations (cohesionless sands and weakly cemented sandstones) and low-permeability formations (tight sandstones and shales). Machine learning (ML), specifically Random Forest models, is applied to identify the parameters influencing the fracture pressure. Key factors include the mean stress, stress differentials, rock properties, and fluid dynamics. The ML models demonstrate strong predictive performance, highlighting the critical role of stress states and flow conditions in the fracture mechanisms. In the case of weakly cemented rocks and cohesionless sands the stress state is by far the most influential parameter that determines the fracturing behaviour. The findings are contextualized using cavity expansion theory and conventional fracturing criteria, providing deeper insights into the fracture behaviour of the various unconventional rocks. The study identifies gaps in the literature, emphasizing the need for further experiments to refine predictive models. Recommendations for future research aim to improve experimental setups and parameter selection, enhancing the understanding of hydraulic fracturing in unconventional formations.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100707"},"PeriodicalIF":3.3,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144549569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermo-mechanical coupling damage constitutive relation of thermally treated rocks: Statistical modeling and verification","authors":"Peilei Zhang,&nbsp;Linqi Huang,&nbsp;Xibing Li","doi":"10.1016/j.gete.2025.100708","DOIUrl":"10.1016/j.gete.2025.100708","url":null,"abstract":"<div><div>Under the inherent high temperature conditions, the rock will obviously be damaged and deteriorated. Developing an objective and rational thermo-mechanical coupling constitutive model is the key to directly assess the rock strength and deformation behavior within a thermodynamic framework. The classical damage model, relying on the strain equivalent hypothesis, struggles to accurately describe the real nonlinear behavior at the compaction stage. For thermally treated rocks, this significantly leads to a larger evolution error. This paper introduces a strain correction method for obtaining effective strain by separating the compaction strain. On this basis, a novel thermo-mechanical coupling statistical constitutive model is developed. Compared to the classical and existing models, the proposed coupling constitutive model demonstrates superior capabilities in describing the uniaxial strength and deformation characteristics under constant heating and heating cycles, especially for the compaction and post-peak strain softening states. Furthermore, the thermo-mechanical coupling damage evolution is analyzed. As temperature increases, the initial damage increases, the experienced deformation also increases, and the overall damage development trends to be flat. In contrast, the influence of heating cycles on rock damage is more significant than that of direct heating. The integration of macroscopic thermodynamic degradation and statistical characterization in constitutive modeling is a reasonable analytical approach, with the parameters have clearly physical meaning. These results can serve as a reference for the thermodynamic constitutive theory in relation to deep rock engineering.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100708"},"PeriodicalIF":3.3,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144563912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surrogate models for development of unconventional shale reservoirs by an integrated numerical approach of hydraulic fracturing, flow and geomechanics, and machine learning","authors":"Prakhar Sarkar ,&nbsp;Sangcheol Yoon ,&nbsp;Jihoon Kim ,&nbsp;Seunghwan Baek ,&nbsp;Alexander Sun ,&nbsp;Hongkyu Yoon","doi":"10.1016/j.gete.2025.100691","DOIUrl":"10.1016/j.gete.2025.100691","url":null,"abstract":"<div><div>We develop well-completion surrogate models by taking an integrated workflow of hydraulic fracturing, flow, geomechanics, and machine learning simulation. There are three steps in the proposed workflow. First, history-matching processes are conducted with the field data including pumping and production data for characterization. Second, full-physics simulation is performed with various parameters of the field development (e.g., cluster spacing, clusters per stage, pumping rates and times, amount of proppant, and well spacing) to generate multiple simulation results by changing the parameters of the completion design with well-known hydraulic fracturing, reservoir, geomechanics simulators to calculate fracture geometry, reservoir depressurization, induced stress changes. The workflow is demonstrated over a field in the Southern Midland Basin. Here, we take two completion scenarios: a single well case followed by a multi-well case. Finally, a Long Short-Term Memory (LSTM) machine learning algorithm is employed to create surrogate models that can replicate the full-physics simulation results. Results show that the trained models applied in the single well and multi-well cases for a particular geological system can provide good accuracy close to those provided by full-physics simulations. Specifically, the site-specific surrogate models can predict fracture parameters (length, height, and surface area) and cumulative production accurately with computational efficiency, suggesting our proposed workflow can be used as a pragmatic tool for expediting the well completion optimization process.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100691"},"PeriodicalIF":3.3,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of rock mass stress, movement, and deformation during injection-production processes in coal mines that have been converted into natural gas storage facilities","authors":"Xuejie Deng ,&nbsp;Xiaoming Shi ,&nbsp;Zhide Wu ,&nbsp;Yuan An ,&nbsp;Jichu Wang ,&nbsp;Shicong Li ,&nbsp;Xifeng Liang ,&nbsp;Benjamin de Wit","doi":"10.1016/j.gete.2025.100703","DOIUrl":"10.1016/j.gete.2025.100703","url":null,"abstract":"<div><div>The rapid growth in natural gas consumption globally has been accompanied by a significant demand increase for storage capacity. Abandoned underground coal mines can be converted into natural gas storage facilities with relatively low construction costs and short construction periods. However, the underground coal pillars and surrounding rock masses are at risk of movement and deformation under the dual effects of injection-production pressures and creep effect. By using mined-out areas of a selected coal mine as the setting to examine performance and effectiveness, this study preliminarily proposes a simplified technical approach for converting abandoned room-and-pillar coal mines into natural gas storage facilities. Also, this study presents and interprets the rock movements, deformations, and fracture characteristics during the injection-production processes. The research shows that: (1) The initial deflection of the roof was 142.91 mm, it increased at a decreasing rate to 226.06 mm after 50 cycles. (2) After injection-production processes the stress and resulting displacement on pillars showed \"arched\" distributions. (3) As injection-production stress increased from 1.8 MPa to 8.2 MPa, the difference in vertical displacement between the roof and pillars decreased from 108.22 mm to 91.28 mm. The instability risk is found when the injection-production pressure approaches in-situ conditions. (4) More injection-production cycles increased the proportional number of fractures in the overlying rock mass, as well as the length and aperture of the fractures. The research findings provide theoretical underpinnings for the conversion of abandoned coal mines to gas storage facilities from engineering practices.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100703"},"PeriodicalIF":3.3,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the settlement behavior of soil–rock mixtures under reservoir water level rise and fall","authors":"Siwei Wang ,&nbsp;Guinan Wang ,&nbsp;Shuyi Li","doi":"10.1016/j.gete.2025.100705","DOIUrl":"10.1016/j.gete.2025.100705","url":null,"abstract":"<div><div>The terrain and landforms in the reservoir area of Baihetan Hydropower Station are complex, with many high mountains and hills. There are many resettlement sites with large scales, and a large amount of soil–rock mixtures are used. The newly filled soil is affected by the periodic rise and fall of the reservoir water level. Therefore, it is of great significance to study the settlement and deformation of high-fill soil–rock mixtures under the action of water level rise and fall. To this end, a device was developed to simulate the settlement of soil–rock mixtures under the action of water level rise and fall in the reservoir area. Large scale physical model experiments were conducted, with model dimensions of 2.8 m × 2.0 m × 2.7 m in length, width, and height. Pore water pressure, soil pressure, and settlement deformation sensors were buried at five different depths of the soil–rock mixtures, and observation windows were set up. The influence of water level rise and fall on the settlement and deformation law of soil and rock filling bodies was studied, and the settlement mechanism was preliminarily revealed (Large pores are filled and compressed due to permeability, while small pores are reduced due to wet dry cycles.).</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100705"},"PeriodicalIF":3.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144492070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of acid fracturing in carbonatite geothermal reservoirs based on a coupled thermo-hydro-mechanical-chemical model considering discrete fracture networks","authors":"Jia Liu ,&nbsp;Wenqi Zhang ,&nbsp;Yi Xue ,&nbsp;Huimin Wang ,&nbsp;Shi-Tong Li ,&nbsp;Yun Zhang ,&nbsp;Weihua Li","doi":"10.1016/j.gete.2025.100704","DOIUrl":"10.1016/j.gete.2025.100704","url":null,"abstract":"<div><div>In the development of carbonate geothermal reservoirs, the implementation of acid fracturing technology is common and essential, effectively enhancing reservoir permeability. It encompasses a sequence of intricate phenomena including solute migration, acid-rock reaction, heat transfer, and deformation. Herein, a comprehensive thermo-hydro-mechanical-chemical (THMC) coupling model considering field-scale discrete fracture networks (DFNs) is established for the process. With the thin elastic layer and fracture element assumptions, the corrosion and deformation of fractures are considered simultaneously. Additionally, the model accounts for the corrosion effects of both bedrock and fracture surfaces, and tracks the evolution of fracture aperture and matrix porosity. Using the proposed model, this study investigates acid fracturing in varying reservoir and operational conditions. It is found that the connectivity of DFN can influence the seepage path of acid fluid, therefore affecting acid concentration transport, which has a significant impact on the reconstruction of reservoir acidification. The acidification effectiveness nonlinearly positively correlates to the rate and concentration of acid injection, while the change of chemical aperture is negatively correlated to the initial fracture aperture. Reservoir temperature has a limited influence on acidification outcomes. The scientific insights provided here are valuable in steering the optimization of acid fracturing in carbonatite reservoirs.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100704"},"PeriodicalIF":3.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermally induced tensile hoop stresses in energy piles: Implications for design and operation","authors":"Ugur Can Erginag ,&nbsp;Mert Guner ,&nbsp;Semra Polat ,&nbsp;Melis Sutman ,&nbsp;Ozer Cinicioglu","doi":"10.1016/j.gete.2025.100702","DOIUrl":"10.1016/j.gete.2025.100702","url":null,"abstract":"<div><div>Energy piles, also known as thermoactive piles, serve a dual purpose: providing structural stability and harvesting shallow geothermal energy. As such, their design must account for both structural and thermal loads. However, current practice typically considers only the axial components of thermal loads. This study aims to investigate thermal loads in three dimensions, with a particular focus on tensile hoop stresses in the clear concrete cover. Through numerical modelling, this study examines the positional and temporal variations of hoop stresses and elucidates the underlying mechanisms. The findings demonstrate that significant tensile hoop stresses can develop within the clear concrete cover during the operation of energy piles, and that these stresses shift positions with seasonal operational changes. Therefore, it is crucial to consider hoop stresses in the design of energy piles to prevent the exceedance of concrete’s structural tensile capacity, a major design concern. A sensitivity analysis was conducted, varying material properties, geometric aspects and operational preferences to identify the relationships between influential parameters and hoop stresses. The study concludes with design and operational recommendations based on these findings.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100702"},"PeriodicalIF":3.3,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144314440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}