Geomechanics for Energy and the Environment最新文献

{"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}

{"title":"A review of fiber optic sensing in geomechanical applications at laboratory and field scales","authors":"Lang Liu ,&nbsp;Marcin Ireneusz Duda ,&nbsp;Antonio F. Salazar Vásquez ,&nbsp;Andreas Nicolas Berntsen","doi":"10.1016/j.gete.2025.100699","DOIUrl":"10.1016/j.gete.2025.100699","url":null,"abstract":"<div><div>Geomechanical characterization and monitoring are essential for subsurface projects, including underground mining, geo-energy production, groundwater management, and geological storages of CO2 and radioactive waste. Traditional measurement techniques often face challenges such as limited spatial coverage and high operational costs. Fiber optic sensing (FOS) offers a promising alternative due to its scalability, durability, and high spatial resolution, making it particularly suitable for harsh environments and large-scale applications. This paper provides a comprehensive and critical review of the use of FOS in geomechanics, covering the principles of quasi- and fully distributed sensing and focusing on strain measurement in both laboratory and field settings. We discuss various techniques for fiber cable installation and explore the integration of FOS with other geomechanical monitoring techniques. Based on the challenges identified in the reviewed studies, we conclude that there is a need for improved fiber coupling and measurement corrections, efficient fiber cable installation, robust data handling and interpretation, and standardization across different geomechanical applications.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100699"},"PeriodicalIF":3.3,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144306720","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":"Investigation of fracture propagation dynamics during multi-stage water injection shearing in fault-fracture reservoirs","authors":"Shichuan Zhang ,&nbsp;Shilong Song ,&nbsp;Buchu Zhang ,&nbsp;Baotang Shen","doi":"10.1016/j.gete.2025.100700","DOIUrl":"10.1016/j.gete.2025.100700","url":null,"abstract":"<div><div>Activation of water injection-induced shear in hot dry rock reservoirs (commonly termed 'hydro-shearing') is a critical technique for enhancing permeability in enhanced geothermal systems, thereby significantly improving the efficiency of reservoir heat extraction. In this study, granite samples from geothermal reservoirs were utilized to fabricate filled jointed granite specimens, and the mechanical properties of water injection-induced shear in granite at various joint angles were examined. The experiments were conducted using a coupled mechanical-hydraulic shear testing system. Additionally, the FRACOD software was employed to simulate the evolution of key shear-enhancing fractures, including wellbore fracturing, joint penetration, and fault activation, in geothermal reservoir formations at different depths. The analysis focused on fracture development patterns, displacement fields, and stress fields at three different depth stages. By integrating a case study from the Yangbajing geothermal project in Tibet, this research investigated the effects of wellbore placement on stress fields, displacement fields, and acoustic emission energy in fracture-type thermal reservoirs. Based on the wellbore model at the 24-meter depth, a systematic sensitivity analysis was conducted to investigate the influence of four critical parameters, namely injection pressure, in-situ stress ratio, fault cohesion, and fault friction angle, on fault slip displacement. The findings indicate that the peak shear strength reduction of granite with different fracture dip angles under water pressure varies, with the 30-degree dip angle granite showing the greatest reduction due to its proximity to the shear failure angle. As burial depth increases, fracture propagation during borehole hydraulic fracturing, natural fracture activation, and fault shear stimulation becomes progressively restricted. Moreover, the wellbore placement significantly affects the response of fracture-type reservoirs, and direct injection into the fault yields superior shear stimulation effects. Injection pressure shows a strong positive correlation with fault slip, as does in-situ stress ratio, while fault cohesion and internal friction angle exhibit negative correlations. Notably, injection pressure emerges as the key factor, contributing 53.73 % to slip displacement variance. These findings provide essential insights for optimizing reservoir and wellbore construction in water-injected shear stimulation projects for hot dry rock geothermal exploitation.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100700"},"PeriodicalIF":3.3,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523011","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":"Coupled thermo-hydro-mechanical modeling of fracture interactions in enhanced geothermal systems","authors":"Heber Fabbri ,&nbsp;Michael A. Maedo ,&nbsp;Pedro Cleto ,&nbsp;Osvaldo L. Manzoli ,&nbsp;Marcelo Sánchez","doi":"10.1016/j.gete.2025.100698","DOIUrl":"10.1016/j.gete.2025.100698","url":null,"abstract":"<div><div>This paper presents the use of the mesh fragmentation technique (MFT) for modeling hydraulic stimulation and heat production in enhanced geothermal systems (EGS). This method simulates evolving hydraulic fractures induced by thermo-hydro-mechanical (THM) phenomena and their interaction with pre-existing natural fractures, forming an interconnected network for water circulation and energy production. The MFT combines high aspect ratio (HAR) elements within a standard finite element (FE), using appropriate constitutive models to describe mechanical, hydraulic, and thermal behaviors. Fracture evolution occurs naturally, governed only by local THM conditions and material properties, without needing special tracking algorithms or remeshing techniques. This approach relies on continuum mechanics and standard FE technology, employing simple models for energy dissipation, flow, and thermal transport due to enhanced porosity and permeability. Three application cases validate this technique. First, the proposed model shows excellent agreement with published thermo-hydraulic solutions, validating its implementation. Second, it effectively handles interactions between natural and hydraulic-driven fractures. Third, it models EGS operation for over 60 years under different <em>in-situ</em> stress scenarios and natural fracture densities. The results show the technique's effectiveness in modeling complex EGS scenarios and demonstrate its potential for optimizing EGS design.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100698"},"PeriodicalIF":3.3,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270086","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 and numerical analysis of hydraulic fracture propagation in naturally fractured granite cores","authors":"Jia He ,&nbsp;Li Zhuang ,&nbsp;Muzi Li ,&nbsp;Zhou Zhou","doi":"10.1016/j.gete.2025.100695","DOIUrl":"10.1016/j.gete.2025.100695","url":null,"abstract":"<div><div>Understanding hydraulic fracture (HF) propagation in naturally fractured granite reservoir is of great importance for deep geothermal energy exploitation. We first conducted laboratory hydraulic fracturing tests on granite outcrops containing natural fractures (NF) and observed deflection of HF toward the NF in a parallel-approach case, and arrested HF in a perpendicular-approach case. Then, a two-dimensional discrete element model is employed to analyze coupled hydro-mechanical processes in the experiments. Our modeling results reveal that, for a parallel-approach case, HF tends to deflect toward the NF when the normal distance between the HF propagation path and NF is less than 5 mm (equivalent to borehole diameter). HF crossing at perpendicular-approach case was found to occur only when two conditions are met: (i) the maximum principal stress at the intersection exceeds the tensile strength of rock, and (ii) no shear failure occurs in NF. Finally, we examined the combined effects of approach angle, NF friction coefficient, and differential principal stress under a constant minimum principal stress (<em>σ</em>_<em>h</em>) of 10 MPa. HF crossing occurred only when the differential principal stress (<em>σ</em>_<em>H</em> <em>- σ</em>_<em>h</em>) ≥ 3 MPa, and was further promoted by larger approach angles (e.g., <em>θ</em> &gt; 50°) and higher NF friction coefficients (e.g., <em>μ</em> &gt; 0.4).</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100695"},"PeriodicalIF":3.3,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261454","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":"Numerical study of the effect of soil-plant-atmosphere interaction under future climate projections and different vegetation covers","authors":"Maryam Sadat Maddah Sadatieh ,&nbsp;Aikaterini Tsiampousi ,&nbsp;Athanasios Paschalis","doi":"10.1016/j.gete.2025.100697","DOIUrl":"10.1016/j.gete.2025.100697","url":null,"abstract":"<div><div>Soil-plant-atmosphere interaction (SPAI) plays a significant role on the safety and serviceably of geotechnical infrastructure. The mechanical and hydraulic soil behaviour varies with the soil water content and pore water pressures (PWP), which are in turn affected by vegetation and weather conditions. Focusing on the hydraulic reinforcement that extraction of water through the plant roots offers, this study couples advances in ecohydrological modelling with advances in geotechnical modelling, overcoming previous crude assumptions around the application of climatic effects on the geotechnical analysis. A methodology for incorporating realistic ecohydrological effects in the geotechnical analysis is developed and validated, and applied in the case study of a cut slope in Newbury, UK, for which field monitoring data is available, to demonstrate its successful applicability in boundary value problems. The results demonstrate the positive effect of vegetation on the infrastructure by increasing the Factor of Safety. Finally, the effect of climate change and changes in slope vegetation cover are investigated. The analysis results demonstrate that slope behaviour depends on complex interactions between the climate and the soil hydraulic properties and cannot be solely anticipated based on climate data, but suctions and changes in suction need necessarily to be considered.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100697"},"PeriodicalIF":3.3,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270087","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}