Geomechanics for Energy and the Environment最新文献

{"title":"Thermally driven fracturing in hot dry rock systems and the role of wellbore cooling","authors":"Abolfazl Ghadimi,&nbsp;Mozhdeh Sajjadi,&nbsp;Mohammad Emami Niri","doi":"10.1016/j.gete.2025.100783","DOIUrl":"10.1016/j.gete.2025.100783","url":null,"abstract":"<div><div>Hydraulic fracturing in hot dry rock (HDR) geothermal reservoirs is strongly influenced by thermal stresses arising from the temperature difference between the injected fluid and the surrounding rock. This study develops a three-dimensional extended finite element (XFEM) model to analyze the dominant early-stage mechanism of wellbore wall cooling and its effect on fracture initiation and propagation. The model captures the coupled thermo-mechanical behavior of the rock and evaluates how thermal contraction at the wellbore alters breakdown and propagation pressures. Sensitivity analyses show that increasing the temperature difference between the injected fluid and the rock significantly reduces the required fracturing pressure, while the magnitude of this effect depends on the in-situ stress field, thermal expansion coefficient, and Young’s modulus. In contrast, variations in thermal conductivity and permeability have negligible impact on the pressure response. The results confirm that wellbore cooling governs the thermal stress contribution during the early stages of fracturing, while fluid-flow-induced thermal gradients become more relevant at later stages. Overall, the findings improve understanding of thermo-mechanical interactions in HDR fracturing and can assist engineers in predicting fracturing pressures and optimizing stimulation strategies in geothermal energy development.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100783"},"PeriodicalIF":3.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884996","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 simulation of refracturing fracture propagation behaviors under non-uniform pore pressure field for the waterflooded reservoir","authors":"Xian Shi ,&nbsp;Xiaoxin Ge ,&nbsp;Wanqiang Gu ,&nbsp;Wei Liu ,&nbsp;Qi Gao ,&nbsp;Anhai Zhong ,&nbsp;Liaoyuan Zhang ,&nbsp;Tiankui Guo","doi":"10.1016/j.gete.2026.100811","DOIUrl":"10.1016/j.gete.2026.100811","url":null,"abstract":"<div><div>Re-fracturing technology is currently one of the most effective stimulation ways to recover or enhance the well performance. However, the effectiveness of re-fracturing may be diminished due to inaccurate refracturing time and refracturing fracture propagation. In this study, the dynamic stress and pore pressure due to water injection and depletion are considered during the re-fracturing process using fully coupled method. Numerical simulations demonstrate that the distribution of pore pressure undergo alterations, thus resulting changes in the magnitude and orientation of in-situ stress. The optimal time window of refracturing can be obtained from the stress field and the stress redirection distance reached its highest value after 200–300d of production and 300d of injection for this given case. The deflection angle and fracturing pressure was used to examine the effect of different geological parameters on refracturing fracture morphologies. The fracture deflection angle increases with the raise of Young's modulus, injection pressure, and pumping rate. On the contrary, the injection well distance and the intersection angle between the direction of well arrays and initial fracture were behaviors the opposite influences on the fracture deflection angle. This work provides more insights to optimize the refracturing treatment for the waterflooded reservoir.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100811"},"PeriodicalIF":3.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385320","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":"Multiscale modeling of hydraulic fracture propagation and design optimization in heterogeneous oil–gas reservoirs","authors":"Jing Li ,&nbsp;Yunpeng Li ,&nbsp;Chun Feng ,&nbsp;Minjie Wen ,&nbsp;Yiming Zhang","doi":"10.1016/j.gete.2026.100806","DOIUrl":"10.1016/j.gete.2026.100806","url":null,"abstract":"<div><div>The strong heterogeneity and low permeability of unconventional reservoirs render multi-well fracturing essential for enhancing recovery rates. However, previous studies have lacked a systematic analysis of the complex coupling mechanisms in multi-well, multi-stage fracturing, especially regarding the significant deviations in predicting fracture propagation paths under realistic three-dimensional stress fields. This study employs the Continuous–Discontinuous Element Method (CDEM) computational framework to construct a three-dimensional, multi-scale coupled flow field-stress field model, achieving a refined simulation from microscopic rupture to macroscopic fracture network evolution. We investigate the formation mechanisms of complex fracture networks during localized near-wellbore injection and examine the influence of key parameters on fracture initiation pressure and propagation trajectories. Furthermore, by varying the operational sequencing of multi-well fracturing, we clarify the stress interference mechanisms governing the evolution of multi-well fracture networks. A comprehensive evaluation system is developed using fracture density as a core metric, integrating fracture morphology, spatial pressure distribution, and fluid flow pathways to rationally assess fracturing effectiveness under multifactorial conditions. This study provides a theoretical basis for optimizing perforation parameters and improving fracturing outcomes in tight oil and gas reservoirs.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"45 ","pages":"Article 100806"},"PeriodicalIF":3.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385342","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":"Mechanism of gas seepage enhancement based on the evolution of micro-pores and energy dissipation in coal under dynamic load","authors":"Di He ,&nbsp;Shugang Li ,&nbsp;Xiangguo Kong ,&nbsp;Haifei Lin ,&nbsp;Yankun Ma ,&nbsp;Yuchu Cai","doi":"10.1016/j.gete.2025.100762","DOIUrl":"10.1016/j.gete.2025.100762","url":null,"abstract":"<div><div>During the development of deep coalbed methane resources, the impact caused by mining disturbance has a significant effect on the evolution of coal pore-fracture and permeability characteristics. Revealing the damage mechanism and gas seepage law of coal in the mining process can provide important basis for the efficient exploitation of coalbed methane. Dynamic impact tests were conducted using the Split Hopkinson Pressure Bar (SHPB) testing system, the T₂ relaxation spectrum and permeability of the impacted coal were measured, respectively. The evolution of pore damage and permeability in coal samples was analyzed from the perspective of energy dissipation. The results showed that as impact pressure increases, adsorption and seepage pores successively dominate the evolutionary process, and the pore fractal dimension of coal samples first increases and then decreases. Magnetic Resonance Imaging (MRI) images reveal obvious linear concentrated damage zones, and these zones lead to the overall evolution of pore structure from point-like dispersion to complex linear interweaving. The permeability of coal samples increases as the impact pressure increases. Under the same impact pressure conditions, the permeability decreases exponentially with an increase in gas pressure. The dissipation energy density and damage variable of coal samples both increase exponentially with the increase of impact pressure. Impact disturbances significantly affect the expansion of pores and fractures in coal. As the damage variable increases, both the porosity and permeability increment of the coal sample exhibit a linear increasing trend. As the extraction time of the test working face increases, the energy of microseismic events and the absolute gas emission show an increasing trend. This indicates that the effect of impact wave causes the gas seepage channel of coal expand, and the permeability enhancement effect is significant.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"44 ","pages":"Article 100762"},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145473893","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":"Effect of mixing time on deep cement mixing in very soft peaty clay","authors":"Ashvitha Yoganathan ,&nbsp;Nadeej H. Priyankara ,&nbsp;Susanga Costa ,&nbsp;Jaspreet Singh Pooni ,&nbsp;Dilan Robert","doi":"10.1016/j.gete.2025.100775","DOIUrl":"10.1016/j.gete.2025.100775","url":null,"abstract":"<div><div>Peaty clay is one of the weakest and most challenging soils to stabilize. Traditionally, pile foundations are used to transfer structural loads to deeper, more stable strata, particularly in areas with peat soils, where surface layers may be too weak or compressible to support heavy loads. However, this approach is often uneconomical for large-area infrastructure such as roads or moderately loaded structures. As a cost-effective alternative, the Deep Mixing Method (DMM) has been widely adopted. DMM involves the in-situ mixing of soil with binders to enhance the engineering properties of soft ground. Despite its extensive application in soft clays and loose sandy soils, the use of DMM in stabilizing soft peaty clays remains relatively underexplored. While various studies have explored binder types and mix proportions, critical factors such as mixing duration and technique, both essential for achieving effective soil stabilization, are not well understood in the context of peaty clays. This research evaluates the effects of mixing time and method, using cement as a binder, on the strength, failure behaviour, and microstructural characteristics of stabilized peaty clay after 7 and 28 days of curing. The findings demonstrate that a 20-minute wet mixing process yields the highest compressive strength, attributed to the formation of densely packed cement hydration products. Specimens mixed under optimal conditions exhibited a split failure mode, similar to concrete, while less or over-mixed samples displayed shear failure. The outcomes from the study are significant for optimizing the DMM as an efficient way of stabilizing these problematic soils.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"44 ","pages":"Article 100775"},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145693075","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":"Pressure relief and zonal extraction and utilization of medium-thick coal seams with high gas content","authors":"Zechen Chang ,&nbsp;Pengxiang Zhao ,&nbsp;Shugang Li ,&nbsp;Diego Maria Barbieri ,&nbsp;Xu Guo ,&nbsp;Weidong Lu ,&nbsp;Quan Jin ,&nbsp;Linyue Jie","doi":"10.1016/j.gete.2025.100764","DOIUrl":"10.1016/j.gete.2025.100764","url":null,"abstract":"<div><div>In this study, the precise layout of the pressure-relief gas drainage boreholes significantly impacted the efficiency of gas drainage and the efficient utilization of gas. This research considered a certain main mining face of the Lutang Coal Mine in Guizhou Province as its research background. The evolution law of the overburden fracture evolution during the mining of high-gas coal seams was analyzed, and a regional division was conducted. A characterization model of the gas migration zone in a high-gas coal seam was constructed. This model was applied to the test working face to perform directional borehole gas drainage and gas utilization. The results showed that the goaf area can be divided into subsidence, rupture, and curved subsidence zones based on the evolutionary trend of the fractures. The goaf area was laterally divided into gas migration and compaction areas based on the density of the fractures. A characterization model of the gas migration zones in high-gas coal seams was established, the stability of rock masses in different regions was analyzed, and the optimal area for directional drilling in the gas migration zone of the fracture was determined. The drilling layout parameters were optimized, and the wellbore gas production, average volume fraction of wellbore gas production, and pure gas production under pressure relief increased by 267 %, 240 %, and 241 %, respectively. The gas-fired power generation increased from 519.3 kWh to 1311.1 kWh. The gas volume fraction in the return air duct and upper corner decreased to between 0.27–0.53 and 0.22–0.43. These results provide theoretical guidance for parameter optimization of extraction boreholes in high-gas coal seams and the utilization of depressurized gas.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"44 ","pages":"Article 100764"},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528496","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":"Investigations into crack evolution during controlled continual laser-based rock processing","authors":"Antash K. Sinha ,&nbsp;Shrikrishna N. Joshi","doi":"10.1016/j.gete.2025.100741","DOIUrl":"10.1016/j.gete.2025.100741","url":null,"abstract":"<div><div>Laser-based rock processing presents a transformative approach for mining, drilling, tunnelling, and geothermal applications by addressing key limitations of conventional mechanical methods, including excessive tool wear and operational inefficiencies. Despite its promise, challenges such as anisotropic rock behaviour, power transmission, formation damage, and instability in subsurface conditions require further investigation. This study examines the effectiveness of continual laser-based rock processing in inducing controlled damage and crack propagation in limestone rock. Distinct stages of rock failure – ranging from pore initiation to fragmentation and segmentation – were identified, revealing a progressive transition from microstructural alteration to macroscopic fracturing. A customized image analysis framework was employed to asses subsurface crack patterns, qualitatively and quantitatively with high fidelity, offering a robust tool for damage quantification. The results underscore the potential of controlled continual laser pulsing as a reliable method for targeted rock disintegration and highlight the role of image-based evaluation in advancing the mechanistic understanding of laser-rock interaction. These findings are expected to contribute positively for the development of next-generation rock-breaking and excavation technologies.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"44 ","pages":"Article 100741"},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158604","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-hydro-mechanical behavior of viscoelastic layered saturated soft soils under non-axisymmetric loadings","authors":"Zhi Yong Ai,&nbsp;Wei Yong Feng,&nbsp;Lei Xu","doi":"10.1016/j.gete.2025.100761","DOIUrl":"10.1016/j.gete.2025.100761","url":null,"abstract":"<div><div>Thermo-hydro-mechanical (THM) coupling behavior of layered transversely isotropic (TI) viscoelastic soils under non-axisymmetric loadings is a critical yet understudied topic in geotechnical engineering, especially for energy infrastructure where thermal gradients and horizontal mechanical loads induce time-dependent deformation. To address this problem, this study investigates the long-term behavior of soft soils under coupled thermo-mechanical loading and establishes a theoretical framework for the non-axisymmetric response of layered saturated viscoelastic media. First, a temperature-dependent viscoelastic soil skeleton model is proposed based on the classical Merchant model. Then, using the elastic–viscoelastic correspondence principle and Laplace transform, the constitutive relationship of the saturated thermo-viscoelastic media is derived in the transformed domain. Subsequently, by introducing the assumption of constant ratios among creep parameters in different directions, a thermo-viscoelastic model for TI media is developed. The governing ordinary differential equations for the non-axisymmetric THM coupling problem are then obtained by combining the governing equations, and applying Fourier series expansion and Hankel transform. The solution is derived using the extended precise integration method. Finally, numerical validation and parametric studies are conducted through representative examples. This semi-analytical solution provides a tool for predicting long-term non-axisymmetric THM deformation of layered TI viscoelastic soils, and offers actionable insights for the design assessment of energy geotechnical structures.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"44 ","pages":"Article 100761"},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145424381","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":"Rock physics and fracture characterization of the Deadwood Formation, Williston Basin: Insights into geothermal resource development","authors":"Moones Alamooti,&nbsp;Shane Namie","doi":"10.1016/j.gete.2025.100737","DOIUrl":"10.1016/j.gete.2025.100737","url":null,"abstract":"<div><div>Sedimentary basin geothermal systems face critical characterization challenges from complex reservoir heterogeneity that traditional assessment methods inadequately address. This study develops an integrated petrophysical-structural framework for the Deadwood Formation in North Dakota's Williston Basin using advanced rock physics modeling and statistical fracture analysis. We employed Differential Effective Medium theory for bimodal pore structures (macropores 10–100 micrometers, micropores &lt;1 micrometer), Kuster-Toksöz analysis for fracture-induced anisotropy with aspect ratios 0.001–1.0, and Gassmann fluid substitution with empirically constrained parameters. Formation Micro-Imager logs at 5 millimeter resolution enabled statistical characterization of 847 fractures across 450 feet, with uncertainty quantification through Monte Carlo simulation. Results demonstrate exceptional geothermal potential with a validated gradient of 34.6°C/km, significantly exceeding typical sedimentary basin values of 25–30°C/km, achieving 160–162°C at economically viable depths of 3.0–3.1 kilometers. Fracture networks follow log-normal distributions with volumetric intensities of 0.07–2.82 fractures/ft³ and a coefficient of variation of 79 %, requiring stochastic modeling approaches. Rock physics modeling successfully discriminates reservoir zones with correlation coefficients exceeding 0.87, identifying Members B and A as optimal targets. Economic analysis demonstrates commercial viability with levelized electricity costs of 8.7 cents per kilowatt-hour (confidence interval: 6.1–12.4), competitive with renewable alternatives. The superior depth-to-temperature ratio of 18.9–19.4 m per degree Celsius provides 25–45 % cost advantages over typical sedimentary prospects. Parameter bounds were constrained by core and log data (φ = 0.08 – 0.18; K_s = 37 – 43 GPa; K-f = 0.02 – 2.3 GPa across steam-brine scenarios), with dry-frame moduli from DEM directly feeding Gassman substitution. This integrated framework advances sedimentary geothermal assessment while establishing replicable protocols for global application, contributing to sustainable energy transition goals.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"44 ","pages":"Article 100737"},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106797","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":"Thermomechanical analysis method for energy piles with skin friction softening and hardening behavior","authors":"Huaibo Song ,&nbsp;Huafu Pei ,&nbsp;Hao Wang","doi":"10.1016/j.gete.2025.100744","DOIUrl":"10.1016/j.gete.2025.100744","url":null,"abstract":"<div><div>Various approaches have been proposed to analyze the thermomechanical behavior of individual energy piles. Although these approaches can account for pile-soil interactions, there is a lack of approaches for continuously describing the full nonlinear range of the load-transfer curve for individual energy piles under thermomechanical loading, including both skin friction softening and the hardening behavior. Therefore, this study developed an analysis method for individual energy piles by considering skin friction softening and hardening behaviors. The developed approach was verified by comparing the simulation results with those of three well-documented field tests, alongside laboratory and centrifuge model tests. The simulation results show a maximum percentage error between the simulation results and the field measurement results is 8.8 %, which is much smaller than that of other methods, indicating a relatively high degree of consistency between the simulation and the actual situation. Besides，the results suggest that the proposed method can capture the full nonlinear range of the load-transfer curve and essential aspects of the pile in terms of the stress and displacement induced by the thermomechanical operation. Finally, a parametric analysis was conducted to study the effects of the model parameters on the energy pile thermomechanical performance. Results show that increasing the dimensionless parameter changes the pile axial thermal stress and displacement oppositely; increasing the residual ratio boosts axial thermal stress, reduces displacements and stress, and moves the neutral point (NP) towards the pile head.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"44 ","pages":"Article 100744"},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106908","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}