Geomechanics for Energy and the Environment最新文献_第3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 : 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

Micromechanical modeling of long-term creep behavior of quasi-brittle rocks considering thermo-mechanical coupling effects 考虑热-力耦合效应的准脆性岩石长期蠕变行为细观力学模拟

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-20 DOI: 10.1016/j.gete.2025.100782

Boran Huang , Jin Zhang , Qi-Zhi Zhu , Lunyang Zhao , Sili Liu

A temperature-dependent micromechanical creep–damage constitutive model is proposed within the framework of irreversible thermodynamics and homogenization theory to investigate the long-term thermo-mechanical behavior of quasi-brittle rocks. The model explicitly couples frictional sliding and microcrack propagation as the dominant modes of energy dissipation, where the friction coefficient, critical damage resistance, and damage threshold are expressed as temperature-dependent functions. Subcritical crack growth is incorporated to capture time-dependent damage accumulation and strain development. Model validation is conducted against triaxial thermo-creep experiments on gneissic granite, deep coals, and Beishan granite. The simulations reproduce the complete creep evolution – primary, secondary (steady-state), and tertiary (accelerated) stages – with relatively few parameters. The results clarify the role of creep rate—controlling factors, reveal the mechanisms of damage evolution and strain-rate acceleration under elevated temperatures, and demonstrate the promoting effect of thermal loading on energy dissipation. This unified framework not only advances the understanding of rock creep under coupled thermal–mechanical fields but also provides a theoretical basis for assessing the long-term thermal stability and reliability of deep underground engineering structures.

在不可逆热力学和均质化理论的框架下，提出了一种温度相关的微力学蠕变损伤本构模型，研究了准脆性岩石的长期热-力学行为。该模型明确耦合摩擦滑动和微裂纹扩展作为能量耗散的主要模式，其中摩擦系数、临界损伤抗力和损伤阈值表示为温度相关函数。亚临界裂纹扩展被纳入捕捉随时间的损伤积累和应变发展。通过对麻质花岗岩、深部煤和北山花岗岩的三轴热蠕变试验对模型进行了验证。该模拟以相对较少的参数再现了完整的蠕变演化过程——初级、二级（稳态）和三级（加速）阶段。研究结果明确了蠕变速率控制因素的作用，揭示了高温下损伤演化和应变速率加速的机理，并论证了热载荷对能量耗散的促进作用。这一统一框架不仅促进了对热-力耦合作用下岩石蠕变的认识，而且为深部地下工程结构的长期热稳定性和可靠性评价提供了理论依据。

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引用次数: 0

Enhanced soil-pile friction using colloidal silica grouting in granular soils 颗粒土中硅胶灌浆增强桩土摩擦

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-13 DOI: 10.1016/j.gete.2025.100780

Alvaro Boiero , Enrique Romero , Marcos Arroyo , Giovanni Spagnoli

Grouting the soil–pile interface can significantly enhance shaft friction in driven and vibrated piles. This observation is well documented for conventional cementitious grouts, but not for alternative low-carbon grouts. In this study the potential of a novel low-viscosity binder—colloidal silica (CS)—to improve steel–granular soil interfaces is explored. Direct shear tests under constant normal stiffness were performed to simulate sand–pile interface behavior on quartz sand specimens permeated with CS. A range of initial relative densities, initial effective normal stresses and constant normal spring stiffness values was selected to mimic conditions likely to be encountered by long piles on offshore sedimentary environments. The study examines the influence of CS dosage and of steel interface roughness. Pre- and post-grout interface shear tests were conducted to evaluate the influence of injection. The results demonstrate that colloidal silica significantly increases interface friction. Practical implications for pile design are discussed.

对桩土界面进行注浆，可显著提高桩身摩阻力。这一观察结果在常规胶凝注浆中得到了很好的证明，但在替代低碳注浆中却没有得到证实。本研究探讨了一种新型低粘度粘结剂——胶体二氧化硅（CS）改善钢-颗粒-土壤界面的潜力。采用恒法向刚度直剪试验模拟了CS渗透石英砂试件的砂-桩界面特性。选择一系列初始相对密度、初始有效正应力和恒定的正向弹簧刚度值来模拟近海沉积环境中长桩可能遇到的情况。研究了CS用量和钢界面粗糙度的影响。通过注浆前和注浆后界面剪切试验，评价注浆对注浆效果的影响。结果表明，胶体二氧化硅显著增加了界面摩擦力。讨论了桩设计的实际意义。

引用次数: 0

A multi-method integration approach for determining draw angles in underground metal mining: A case study of the kuogeshaye gold mine 地下金属开采角度确定的多方法集成方法——以郭格沙耶金矿为例

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-11 DOI: 10.1016/j.gete.2025.100777

Jiahui Tian , Ruiyang Bi , Jian Zhou , Zupu Xuan , Kun Du

Accurate determination of the draw angle is critical for defining surface subsidence boundaries and ensuring the safety of surface infrastructure during mining operations. To overcome the limitations of single-method approaches, this study proposes a multi-method integration framework. Using the Kuogeshaye Gold Mine as a case study, the framework effectively combines theoretical calculation, particle swarm optimization–support vector machine prediction, and numerical simulation. The maximum relative error between the results achieved using the three methods was only 5.1 %. Additionally, an analytic hierarchy process-based weighted fusion strategy was used to integrate the results from the three methods, yielding a more reliable determination. The final draw angles were 73.5° and 74.7° for a hanging wall and footwall, respectively. Engineering applications demonstrated that this method significantly enhanced the accuracy of surface subsidence zone-boundary delineation, offering a transferable methodology for determining the rock draw angle and ensuring safe mining in deep mines.

准确确定地表倾角对于确定地表沉陷边界、保障地表基础设施安全是至关重要的。为了克服单一方法方法的局限性，本研究提出了一个多方法集成框架。以Kuogeshaye金矿为例，该框架有效地将理论计算、粒子群优化-支持向量机预测和数值模拟相结合。三种方法测定结果的最大相对误差仅为5.1% %。此外，采用基于层次分析法的加权融合策略对三种方法的结果进行综合，得到更可靠的结果。上盘和下盘的最终抽采角度分别为73.5°和74.7°。工程应用表明，该方法显著提高了地表沉陷带边界圈定的精度，为确定深部矿山岩层倾角、保障矿山安全开采提供了一种可转移的方法。

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引用次数: 0

Mathematical foundations for play-agnostic thermo-poro-hydro-mechanical modeling of hydraulic fracture initiations from perforated wells: Towards a predictive tool 射孔井水力裂缝起裂的热-孔隙-水力力学模型的数学基础：一种预测工具

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-11 DOI: 10.1016/j.gete.2025.100778

Nassim Bouabdallah, Andreas Michael

The initiation of hydraulically-induced (fluid-driven) fractures for stimulation purposes in hydrocarbon-rich reservoirs can be predictively modeled employing a physics-based approach via a novel pseudo-three-dimensional (pseudo-3D) approximation. The rationale for such an approach lies in the orientation of hydraulic fracture (HF) initiation being determined by mapping stress distributions around the intersection between the wellbore and a perforation tunnel (i.e., the perforation base); the presumed location of HF initiations. The derived closed-form expressions couple thermal, poroelastic, and hydromechanical effects (TPHM) and are controlled by the reservoir’s rock properties and the fluid pressures at the perforation base. Most importantly, this physics-based approach is play-agnostic. The developed TPHM model enables identifying favorable conditions for HFs initiating perpendicularly to the wellbore (“transverse-HF initiations,” as opposed to “longitudinal-HF initiations” axially to the wellbore). This is the desired orientation of HF initiation in virtually every reservoir-stimulation-treatment target zone in today’s prolific low-permeability shale plays; longitudinal-HF initiations can induce several completion and production-related issues triggered by near-wellbore HF tortuosity. The utility of the play-agnostic TPHM model is easily reversible, as it can help estimate the fracture initiation pressure (FIP) at a given orientation of HF initiation. These FIP values provide the basis for formation-breakdown-pressure (FBP) predictions. By solving the derived closed-form expression, our dual-utility, play-agnostic TPHM model provides means for engineers to understand how to manipulate human-controlled parameters from the surface (such as pressurization rates and perforation phasing) to optimize stimulation treatments across various target rock formations, ultimately maximizing the well productivity. Through the promotion of transverse-HF initiation at the lowest possible FBP, near-wellbore fluid tortuosity is suppressed, minimizing early screenouts and enhancing stimulated-well performance that leads to overall more efficient stimulation treatments.

在富含油气的储层中，以增产为目的的水力诱导（流体驱动）裂缝的形成可以采用一种基于物理的方法，通过一种新的伪三维（pseudo-3D）近似方法进行预测建模。这种方法的基本原理是，通过绘制井筒和射孔隧道（即射孔底部）相交处的应力分布来确定水力裂缝（HF）起裂的方向；HF起爆的假定位置。导出的封闭表达式耦合了热、孔弹性和流体力学效应（TPHM），并受储层岩石性质和射孔底部流体压力的控制。最重要的是，这种基于物理的方法是游戏不可知论的。开发的TPHM模型能够识别hf垂直于井筒的有利条件（“横向hf起始”，而不是“纵向hf起始”）。在当今多产的低渗透页岩区，这是几乎所有储层增产处理目标区中HF起爆的理想方向；由于近井HF弯曲，纵向HF起爆会引发一些完井和生产相关的问题。与储层无关的TPHM模型的实用性是很容易逆转的，因为它可以帮助估计在HF起裂的给定方向上的裂缝起裂压力（FIP）。这些FIP值为地层破裂压力（FBP）预测提供了基础。通过求解推导出的封闭表达式，我们的双重实用、不可知储层的TPHM模型为工程师提供了一种方法，让他们了解如何从地面操纵人为控制的参数（如加压速率和射孔相位），以优化不同目标岩层的增产措施，最终实现油井产能最大化。通过在尽可能低的FBP下促进横向hf启动，可以抑制近井流体弯曲度，最大限度地减少早期筛出，提高增产井的性能，从而实现更有效的增产处理。

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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 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

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 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

An effective poroelastic model for fractured porous media 裂缝性多孔介质的有效孔隙弹性模型

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-01 DOI: 10.1016/j.gete.2025.100772

Renato E.B. Poli, D. Nicolas Espinoza, Kamy Sepehrnoori

Fractures are present in many types of porous media, including rock formations. While the impact of the fractures on fluid flow processes has been extensively investigated, methods for rigorous poromechanical upscaling including fluid mass and momentum conservation into effective models are still limited. Considering the limitations of experimental assessment of large rock masses, this work proposes the use of a numerical approach to understand and calculate the effective poromechanical quasi-static response of a fractured porous medium. First, we detail the design and validation of a high-performance poroelastic simulator with conforming fractures. Then a series of sensitivity analyses investigates the effective response of a linear poroelastic medium with a fracture network. An unstructured mesh generator coupled to a Monte Carlo simulation engine helps explore the intrinsic uncertainties of the system, both in the continuum and fracture domains. The findings indicate that fracture networks are most impactful in scenarios of low effective stress, which is typically the case of shallow rock formations, high pore pressure, or fluid injection at low temperatures. The impact on the effective drained bulk modulus

\overset{̅}{K}

, the drained Poisson ratio

\overset{̅}{ν}

and the drained Biot coefficient

\overset{̅}{α}

is strongly correlated to the fracture density, while the effective undrained Skempton

\overset{̅}{B}

and Biot Modulus

\overset{̅}{M}

are more sensitive to fluid compressibility as the fluid storage added due to fracture volume and deformation becomes dominant. Finally, the uncertainty assessment provides recommendations for geomechanical modelers attempting to capture effective poroelastic parameterization at the field scale. For example, contrary to usual practice, it is correct to assume a large-scale effective Biot coefficient near unity for highly fractured stiff rocks such as dolomite or granite.

裂缝存在于许多类型的多孔介质中，包括岩层。虽然裂缝对流体流动过程的影响已经得到了广泛的研究，但将流体质量和动量守恒纳入有效模型的严格孔隙力学升级方法仍然有限。考虑到大型岩体实验评估的局限性，本工作提出使用数值方法来理解和计算裂隙多孔介质的有效孔隙力学准静态响应。首先，我们详细介绍了具有一致性裂缝的高性能孔隙弹性模拟器的设计和验证。在此基础上，通过一系列的灵敏度分析，研究了含裂缝网络的线性孔隙弹性介质的有效响应。与蒙特卡罗模拟引擎相结合的非结构化网格生成器有助于探索系统在连续体和断裂域中的内在不确定性。研究结果表明，裂缝网络在有效应力较低的情况下影响最大，通常是在浅岩层、高孔隙压力或低温下注入流体的情况下。有效泄油体积模量K′′、泄油泊松比ν′′和泄油Biot系数α′′的影响与裂缝密度密切相关，而有效泄油Skempton B′′和Biot模量M′′对流体可压缩性更为敏感，裂缝体积和变形增加的储液量占主导地位。最后，不确定性评估为试图在现场尺度上捕获有效孔隙弹性参数化的地质力学建模者提供了建议。例如，与通常做法相反，对于白云岩或花岗岩等高度断裂的坚硬岩石，假设大尺度有效比奥系数接近统一是正确的。

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引用次数: 0

Strata control methods and optimization design for mining earthquake prevention and environmental protection 矿山防震环保岩层控制方法及优化设计

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-01 DOI: 10.1016/j.gete.2025.100774

Tiening Wang , Guangli Guo , Huaizhan Li , Hejian Yin , Hui Zheng , Fanzhen Meng , Liangui Zhang

High position super-thick overburden is a common geological structure in coal-bearing strata, and its fracture movement is extremely likely to trigger serious dynamic disasters. Large-scale coal mining is prone to cause the rupture of high position super-thick overburden, accompanied by a huge release of energy. Meanwhile, the disorderly accumulation of associated gangue has also led to severe ecological degradation. To address these challenges, this paper proposes a strata control method considering mine earthquake prevention and gangue treatment (SCMEG). Based on this, the stability evaluation model of high position super-thick overburden and the stability evaluation model of composite support pillar have been established. Then combined with gray wolf algorithm, the optimization design process driven by gangue disposal efficiency is put forward. The research achievement has been applied to Ordos mine, yielding optimal design parameters: caving mining width of 340 m, grouting filling width of 240 m. The comparative analysis results indicate that the optimized plan of SCMEG demonstrates significant advantages: it effectively prevents large-scale energy accumulation in the high position super-thick overburden, ensures the overall integrity of the overburden, and maintains the long-term stability of the composite support pillar. Simultaneously, the amount of gangue disposal matches the mining output, enabling efficient and large-scale gangue disposal in the mining area. The research provides theoretical support for the coordinated development of environmental protection and safe production in ecologically fragile mining areas.

高位超厚覆岩是含煤地层中常见的地质构造，其断裂运动极有可能引发严重的动力灾害。大规模采煤容易造成高位超厚覆岩破裂，并伴随巨大的能量释放。同时伴生脉石的无序堆积也导致了严重的生态退化。针对这些挑战，本文提出了一种考虑矿山防震与矸石处理的地层控制方法。在此基础上，建立了高位超厚覆盖层稳定性评价模型和复合支护矿柱稳定性评价模型。然后结合灰狼算法，提出了以矸石处理效率为驱动的优化设计过程。将研究成果应用于鄂尔多斯矿，得出了最优设计参数：崩落开采宽度340 m，注浆充填宽度240 m。对比分析结果表明，SCMEG优化方案具有显著优势，有效防止了高位超厚覆岩的大规模能量积聚，保证了覆岩的整体完整性，保持了复合支护柱的长期稳定性。同时，矸石处置量与开采产量相匹配，实现了矿区矸石的高效大规模处置。研究结果为生态脆弱矿区环境保护与安全生产协调发展提供了理论支持。

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引用次数: 0

Sealing simulation experiment of old well collapse debris in carbon capture and storage (CCS) 碳捕集与封存中老井坍塌碎屑密封模拟实验

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-12-01 DOI: 10.1016/j.gete.2025.100776

Yuda Zhang , Jingnan Dong , Guangjie Yuan , Yan Xia , Hong Zhang , Pan Fu

Carbon storage in depleted reservoirs has emerged as a critical technology for mitigating atmospheric CO₂ concentrations, where the sealing integrity of old wells constitutes a pivotal factor in site selection. This study investigates the sealing performance of old wells containing fish and buried by wellbore collapse debris through comprehensive experimental approaches, including full-scale wellbore debris sealing simulations and small-scale core permeability tests. The experimental design systematically examined key variables including debris composition, compaction degree, and permeability characteristics under varying hydraulic pressures. Results demonstrate two distinct failure mechanisms: (1) gas breakthrough occurring at pressure differentials of 1.3–2.7 MPa with approximately 30-second response time, where gas migration predominantly follows interfacial pathways between compacted debris (permeability <0.031 D) and casing/fish structures; and (2) persistent gas leakage through debris pore networks, exhibiting permeability ranges of 0.0024–0.031 D. These findings provide fundamental insights into failure dynamics of debris-sealed abandoned wells, offering critical empirical data for safety assessment of CCS/CCUS reservoir candidates. The experimental methodology establishes a replicable framework for evaluating wellbore sealing integrity under simulated reservoir conditions.

枯竭储层中的碳储存已成为降低大气CO₂浓度的关键技术，其中老井的密封完整性是选址的关键因素。本研究通过全面的实验方法，包括全尺寸井筒碎屑密封模拟和小规模岩心渗透率测试，研究了含鱼井和井筒坍塌碎屑埋藏的老井的密封性能。试验设计系统地检查了不同水压下的关键变量，包括碎屑成分、压实程度和渗透性特征。结果显示了两种不同的破坏机制：(1)气侵发生在压力差为1.3-2.7 MPa时，响应时间约为30秒，气体运移主要沿着压实碎屑（渗透率<；0.031 D）与套管/鱼体结构之间的界面通道进行；(2)碎屑孔隙网络中持续的气体泄漏，渗透率范围为0.0024 ~ 0.031 d。这些发现为碎屑密封废弃井的破坏动力学提供了基本见解，为CCS/CCUS候选储层的安全性评估提供了关键的经验数据。该实验方法建立了一个可复制的框架，用于在模拟油藏条件下评估井筒密封完整性。

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引用次数: 0