Geomechanics for Energy and the Environment最新文献_第4页

Thermally driven fracturing in hot dry rock systems and the role of wellbore cooling 热干岩系统中的热驱动压裂及井筒冷却作用

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2026-03-01 Epub Date: 2025-12-22 DOI: 10.1016/j.gete.2025.100783

Abolfazl Ghadimi, Mozhdeh Sajjadi, Mohammad Emami Niri

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.

热干岩（HDR）地热储层水力压裂受注入流体与围岩温差产生的热应力的强烈影响。建立了三维扩展有限元（XFEM）模型，分析了井筒壁冷却的主要早期机理及其对裂缝萌生和扩展的影响。该模型捕获了岩石的耦合热-力学行为，并评估了井筒中的热收缩如何改变破裂和扩展压力。敏感性分析表明，增加注入流体与岩石之间的温差可以显著降低所需的压裂压力，而这种影响的大小取决于地应力场、热膨胀系数和杨氏模量。相比之下，导热系数和渗透率的变化对压力响应的影响可以忽略不计。结果证实，在压裂初期，井筒冷却对热应力的贡献起主导作用，而在压裂后期，流体诱导的热梯度对热应力的影响更大。总的来说，这些发现提高了对HDR压裂热-力学相互作用的理解，可以帮助工程师预测压裂压力，优化地热能源开发中的增产策略。

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引用次数: 0

Numerical simulation of refracturing fracture propagation behaviors under non-uniform pore pressure field for the waterflooded reservoir 水淹油藏非均匀孔隙压力场下重复压裂裂缝扩展行为的数值模拟

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2026-03-01 Epub Date: 2026-02-26 DOI: 10.1016/j.gete.2026.100811

Xian Shi , Xiaoxin Ge , Wanqiang Gu , Wei Liu , Qi Gao , Anhai Zhong , Liaoyuan Zhang , Tiankui Guo

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.

再压裂技术是目前恢复或提高油井性能最有效的增产措施之一。然而，由于重复压裂时间和重复压裂裂缝扩展不准确，可能会降低再压裂的效果。本研究采用全耦合方法考虑了再压裂过程中的动应力和注、衰竭引起的孔隙压力。数值模拟表明，孔隙压力的分布发生了变化，从而导致地应力的大小和方向发生了变化。从应力场可以得到重复压裂的最佳时间窗，在生产200 ~ 300d、注入300d时，应力重定向距离达到最大值。利用压裂斜角和压裂压力考察了不同地质参数对重复压裂裂缝形态的影响。裂缝挠度随杨氏模量、注入压力和泵注速率的增大而增大。注水井距、井阵方向与初始裂缝交角对裂缝挠度的影响相反。这项工作为优化水淹油藏的重复压裂处理提供了更多的见解。

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引用次数: 0

Multiscale modeling of hydraulic fracture propagation and design optimization in heterogeneous oil–gas reservoirs 非均质油气藏水力裂缝扩展多尺度建模与设计优化

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2026-03-01 Epub Date: 2026-02-21 DOI: 10.1016/j.gete.2026.100806

Jing Li , Yunpeng Li , Chun Feng , Minjie Wen , Yiming Zhang

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.

非常规油藏非均质性强、渗透率低，因此多井压裂是提高采收率的关键。然而，以往的研究缺乏对多井、多段压裂复杂耦合机理的系统分析，特别是在实际三维应力场下裂缝扩展路径的预测存在较大偏差。本研究采用连续-不连续单元法（CDEM）计算框架，构建三维多尺度耦合流场-应力场模型，实现了从微观破裂到宏观裂缝网络演化的精细模拟。研究了局部近井注入过程中复杂裂缝网络的形成机制，并研究了关键参数对裂缝起裂压力和扩展轨迹的影响。此外，通过改变多井压裂的作业顺序，我们阐明了控制多井裂缝网络演化的应力干扰机制。建立了以裂缝密度为核心指标，综合裂缝形态、空间压力分布、流体流动路径等因素，合理评价多因素条件下压裂效果的综合评价体系。该研究为致密油气储层优化射孔参数、提高压裂效果提供了理论依据。

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引用次数: 0

Mechanism of gas seepage enhancement based on the evolution of micro-pores and energy dissipation in coal under dynamic load 动载下煤体微孔演化与能量耗散的瓦斯渗流强化机理

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-01 Epub Date: 2025-10-31 DOI: 10.1016/j.gete.2025.100762

Di He , Shugang Li , Xiangguo Kong , Haifei Lin , Yankun Ma , Yuchu Cai

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.

在深部煤层气资源开发过程中，采动扰动对煤层孔隙-裂隙及渗透率特征的演化具有重要影响。揭示煤在开采过程中的破坏机理和瓦斯渗流规律，可为煤层气的高效开采提供重要依据。采用分离式霍普金森压杆（SHPB）试验系统进行动态冲击试验，分别测量了冲击煤的T2弛豫谱和渗透率。从能量耗散的角度分析了煤样孔隙损伤和渗透率的演化过程。结果表明：随着冲击压力的增大，吸附孔和渗流孔先后主导演化过程，煤样孔隙分形维数先增大后减小；核磁共振成像（MRI）图像显示出明显的线性集中损伤区，这些损伤区导致孔隙结构整体由点状分散向复杂的线性交织演变。煤样渗透率随冲击压力的增大而增大。在相同冲击压力条件下，渗透率随气体压力的增加呈指数递减。随着冲击压力的增大，煤样的耗散能密度和损伤变量均呈指数增长。冲击扰动对煤中孔隙和裂隙的扩展有显著影响。随着损伤变量的增大，煤样孔隙度和渗透率增量均呈线性增加趋势。随着试验工作面抽采时间的增加，微震事件能量和瓦斯绝对涌出量均呈增加趋势。说明冲击波作用使煤体瓦斯渗流通道扩张，增强渗透性效果显著。

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引用次数: 0

Effect of mixing time on deep cement mixing in very soft peaty clay 搅拌时间对极软泥炭土中深层水泥搅拌的影响

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-01 Epub Date: 2025-11-25 DOI: 10.1016/j.gete.2025.100775

Ashvitha Yoganathan , Nadeej H. Priyankara , Susanga Costa , Jaspreet Singh Pooni , Dilan Robert

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.

泥炭土是最脆弱和最具挑战性的土壤之一。传统上，桩基被用来将结构荷载转移到更深、更稳定的地层，特别是在有泥炭土的地区，那里的表层可能太弱或可压缩，无法支撑重物。然而，对于大面积的基础设施，如道路或中等负荷的结构，这种方法往往不经济。作为一种经济有效的替代方法，深度混合法（DMM）已被广泛采用。DMM是将土与粘结剂原位混合，以提高软土地基的工程性能。尽管DMM在软粘土和松散砂质土中得到了广泛的应用，但其在软泥炭土稳定中的应用仍相对较少。虽然各种各样的研究已经探索了粘结剂类型和混合比例，但在泥炭粘土的背景下，诸如混合时间和技术等对实现有效土壤稳定至关重要的关键因素还没有得到很好的理解。本研究评估了搅拌时间和方法的影响，使用水泥作为粘合剂，对强度，破坏行为和稳定的泥炭粘土在养护7天和28天后的微观结构特征。研究结果表明，20分钟的湿搅拌过程产生了最高的抗压强度，这是由于形成了密实的水泥水化产物。在最佳搅拌条件下，试件表现出与混凝土相似的劈裂破坏模式，而拌合过少或过少的试件则表现出剪切破坏模式。研究结果对优化DMM作为稳定这些问题土壤的有效方法具有重要意义。

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引用次数: 0

Pressure relief and zonal extraction and utilization of medium-thick coal seams with high gas content 高含气量中厚煤层卸压与分区开采利用

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-01 Epub Date: 2025-11-04 DOI: 10.1016/j.gete.2025.100764

Zechen Chang , Pengxiang Zhao , Shugang Li , Diego Maria Barbieri , Xu Guo , Weidong Lu , Quan Jin , Linyue Jie

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.

在本研究中，泄压瓦斯抽放钻孔的精确布置对瓦斯抽放效率和瓦斯的高效利用有重要影响。本研究以贵州鲁塘煤矿某主采工作面为研究背景。分析了高瓦斯煤层开采过程中覆岩裂隙演化规律，并进行了区域划分。建立了高瓦斯煤层天然气运移带的表征模型。将该模型应用于试验工作面进行定向井瓦斯抽采和瓦斯利用。结果表明：根据裂缝演化趋势，采空区可划分为沉陷带、破裂带和弯曲沉陷带；根据裂缝密度将采空区横向划分为气体运移区和压实区。建立了高瓦斯煤层气体运移带的表征模型，分析了不同区域岩体的稳定性，确定了裂缝气体运移带的最佳定向钻井区域。通过优化钻井布局参数，井筒产气量、井筒产气量平均体积分数和卸压下的纯气量分别提高了267 %、240 %和241 %。燃气发电量从519.3千瓦时增加到1311.1千瓦时。回风管道和上角的气体体积分数下降到0.27-0.53 ~ 0.22-0.43之间。研究结果为高瓦斯煤层抽采钻孔参数优化及降压瓦斯利用提供了理论指导。

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引用次数: 0

Investigations into crack evolution during controlled continual laser-based rock processing 可控连续激光岩石加工过程中裂纹演化的研究

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-01 Epub Date: 2025-09-14 DOI: 10.1016/j.gete.2025.100741

Antash K. Sinha , Shrikrishna N. Joshi

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.

基于激光的岩石加工为采矿、钻井、隧道和地热应用提供了一种革命性的方法，解决了传统机械方法的主要局限性，包括工具过度磨损和操作效率低下。尽管前景光明，但诸如各向异性岩石行为、电力传输、地层损害和地下条件不稳定性等挑战需要进一步研究。本研究考察了连续激光岩石加工在石灰岩中诱导可控损伤和裂纹扩展方面的有效性。岩石破坏的不同阶段——从孔隙形成到破碎和分割——被识别出来，揭示了从微观结构改变到宏观压裂的渐进过渡。采用定制的图像分析框架对地下裂纹模式进行高保真的定性和定量评估，为损伤量化提供了强大的工具。这些结果强调了可控连续激光脉冲作为一种可靠的定向岩石崩解方法的潜力，并强调了基于图像的评价在推进激光-岩石相互作用机理理解方面的作用。预计这些发现将对下一代破岩和挖掘技术的发展作出积极贡献。

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引用次数: 0

Thermo-hydro-mechanical behavior of viscoelastic layered saturated soft soils under non-axisymmetric loadings 非轴对称荷载作用下粘弹性层状饱和软土的热-水-力学行为

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-01 Epub Date: 2025-10-23 DOI: 10.1016/j.gete.2025.100761

Zhi Yong Ai, Wei Yong Feng, Lei Xu

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.

非轴对称荷载作用下层状横向各向同性粘弹性土的热-水-力耦合行为是岩土工程中一个关键但尚未得到充分研究的课题，特别是对于热梯度和水平机械载荷引起时间相关变形的能源基础设施而言。为了解决这一问题，本研究研究了热-力耦合加载下软土的长期行为，并建立了层状饱和粘弹性介质非轴对称响应的理论框架。首先，在经典Merchant模型的基础上，建立了温度相关的粘弹性土骨架模型。然后，利用弹粘弹性对应原理和拉普拉斯变换，推导了饱和热粘弹性介质在变换域内的本构关系。随后，通过引入蠕变参数在不同方向上的恒比假设，建立了TI介质的热粘弹性模型。结合控制方程，应用傅立叶级数展开和汉克尔变换，得到了非轴对称THM耦合问题的控制常微分方程。采用扩展精确积分法推导了该问题的解。最后，通过典型算例进行数值验证和参数化研究。这种半解析解为预测层状TI粘弹性土的长期非轴对称THM变形提供了工具，并为能源岩土结构的设计评估提供了可行的见解。

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引用次数: 0

Quantifying thermo-hydraulic coupling in fractured geothermal reservoirs through discrete fracture network modeling based on field characterization 基于现场表征的离散裂缝网络建模量化裂缝性地热储层热-水力耦合

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-01 Epub Date: 2025-11-21 DOI: 10.1016/j.gete.2025.100773

Yanyan Li , Yuanshuo Ma , Ximin Bai , Binghong Fan

Fracture networks govern geothermal resource potential by controlling fluid flow and heat transfer dynamics. However, dynamic coupling mechanisms between fracture networks and thermo-hydraulic processes remain poorly quantified, hindering predictive capacity for long-term geothermal performance. To overcome this limitation, this study develops a geologically representative discrete fracture network (DFN) model by applying Monte Carlo simulation to field-measured fracture data from a granite outcrop in southwestern China. A coupled thermo-hydraulic model is established using the DFN model, validated against Lauwerier's analytical solution and numerically simulated. By quantifying thermal breakthrough, our results reveal that the system's sensitivity to fracture aperture decreases with increasing aperture, and that fracture aperture exerts a far stronger influence on thermal breakthrough than injection pressure. Besides, higher rock thermal conductivity enhances sustainable heat production by delaying thermal depletion through improved heat replenishment from the reservoir matrix. Quantified pressure impacts show 22 MPa delivers 50 % higher initial heat extraction than 18 MPa, but the marginal gain in cumulative heat production per unit pressure difference decreases, revealing the short-term advantages and long-term limitations of high-pressure operations.

裂缝网络通过控制流体流动和传热动力学来控制地热资源潜力。然而，裂缝网络与热水力过程之间的动态耦合机制仍然难以量化，这阻碍了对长期地热性能的预测能力。为了克服这一局限性，本研究采用蒙特卡罗模拟方法，建立了具有地质代表性的离散裂缝网络（DFN）模型，并对中国西南花岗岩露头的现场测量裂缝数据进行了分析。采用DFN模型建立了热-液耦合模型，并对Lauwerier解析解进行了验证和数值模拟。通过对热突破进行量化，研究结果表明，系统对裂缝孔径的敏感性随着裂缝孔径的增大而降低，裂缝孔径对热突破的影响远大于注入压力。此外，较高的岩石导热系数通过提高储层基质的热量补充来延缓热耗竭，从而增强了可持续的产热能力。量化压力影响表明，与18 MPa相比，22 MPa的初始热抽提量高出50% %，但单位压差累积产热边际增益减小，揭示了高压作业的短期优势和长期局限性。

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引用次数: 0

Rock physics and fracture characterization of the Deadwood Formation, Williston Basin: Insights into geothermal resource development 威利斯顿盆地Deadwood组岩石物理与裂缝特征：对地热资源开发的启示

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-01 Epub Date: 2025-09-12 DOI: 10.1016/j.gete.2025.100737

Moones Alamooti, Shane Namie

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 <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.

沉积盆地地热系统的表征面临着复杂储层非均质性的挑战，而传统的评价方法无法充分解决这一问题。本研究利用先进的岩石物理建模和统计裂缝分析技术，为北达科他州威利斯顿盆地的Deadwood组开发了一个综合的岩石物理结构框架。我们采用微分有效介质理论分析双峰孔隙结构（大孔隙10-100微米，微孔隙& 1微米），Kuster-Toksöz分析裂缝诱导的各向异性，宽高比为0.001-1.0，并采用经验约束参数的Gassmann流体替代。5毫米分辨率的地层微成像仪测井记录了450英尺内847条裂缝的统计特征，并通过蒙特卡罗模拟进行了不确定性量化。结果表明，该地区地热潜力巨大，有效梯度为34.6°C/km，显著超过典型沉积盆地值25-30°C/km，在3.0-3.1公里的经济可行深度达到160-162°C。裂缝网络遵循对数正态分布，体积强度为0.07-2.82裂缝/ft3，变异系数为79 %，需要随机建模方法。岩石物理建模成功识别出相关系数大于0.87的储层，确定B段和A段为最佳储层。经济分析表明，每千瓦时8.7美分的电力成本（置信区间：6.1-12.4）具有商业可行性，与可再生能源替代品具有竞争力。与典型的沉积勘探区相比，18.9-19.4 m /℃的优越深温比提供了25 - 45% %的成本优势。参数边界受岩心和测井数据约束（在蒸汽-盐水情景下，φ = 0.08 - 0.18; Ks = 37 - 43 GPa; K-f = 0.02 - 2.3 GPa）， DEM中的干框架模量直接提供Gassman代入。这一综合框架推进了沉积地热评估，同时建立了可复制的全球应用协议，有助于实现可持续能源转型目标。

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