Geoenergy Science and Engineering最新文献_第3页

Impact of ethylene glycol on dissociation kinetics of CH4 and CO2 hydrates: A molecular dynamics investigation 乙二醇对CH4和CO2水合物解离动力学的影响：分子动力学研究

IF 4.6 0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2026-05-01 Epub Date: 2026-01-27 DOI: 10.1016/j.geoen.2026.214406

Bidesh Kumar Hembram , Tushar Sharma , Mahmood M.S. Abdullah , Krishna Raghav Chaturvedi , Vishnu Chandrasekharan Nair

Gas hydrates are ice-like crystals formed from gas and water under high pressure and low temperature, is a source of energy and causes pipeline flow assurance issue risking shutdowns, equipment damage, and safety hazards in oil and gas operations. To mitigate these issues, flow assurance strategies often involve using hydrate inhibitors (like ethylene glycol), insulation, and heating systems to maintain conditions that prevent hydrate formation, ensuring safe and continuous gas transport. Molecular dynamics (MD) simulations offer a powerful tool to investigate the behaviour of gas hydrates at the atomic level, providing insights into their formation, stability, and interactions. This study explores the impact of ethylene glycol on the dissociation and stability of CO₂ and methane hydrates together in a system through MD simulations. While inhibitors are commonly used in the industry to prevent hydrate formation and assist in dissociation, their precise role in this gas exchange mechanism demands more detailed exploration. In this study, we investigated the potential of ethylene glycol as a chemical additive to promote gas hydrate dissociation, though its effects are not yet fully understood. Using molecular dynamics (MD) simulations, we explored parameters such as radial distribution function (RDF), mean square displacement (MSD), and diffusion coefficients to examine the impact of ethylene glycol across various temperatures (270.15 K–300 K) and concentrations (0–15 % V/V). The results indicate that gas dissociation accelerates by 150 % with rising temperatures, allowing methane to escape more rapidly into the simulation box, thereby enabling controlled gas production. Additionally, a 10 % increase in glycol concentration destabilizes hydrate structure. Based on these findings, we recommend using ethylene glycol at 10 % v/v for gas hydrate dissociation at 280.15 K.

天然气水合物是由天然气和水在高压和低温下形成的冰状晶体，是一种能量来源，会导致管道流动保障问题，有可能导致石油和天然气作业中的关闭、设备损坏和安全隐患。为了缓解这些问题，流动保证策略通常包括使用水合物抑制剂（如乙二醇）、绝缘和加热系统来维持防止水合物形成的条件，确保安全连续的天然气输送。分子动力学（MD）模拟为在原子水平上研究天然气水合物的行为提供了一个强大的工具，可以深入了解它们的形成、稳定性和相互作用。本研究通过MD模拟探讨了乙二醇对系统中CO2和甲烷水合物的解离和稳定性的影响。虽然抑制剂在工业中通常用于防止水合物形成和帮助解离，但它们在这种气体交换机制中的确切作用需要更详细的探索。在这项研究中，我们研究了乙二醇作为化学添加剂促进天然气水合物解离的潜力，尽管其作用尚未完全了解。利用分子动力学（MD）模拟，研究了径向分布函数（RDF）、均方位移（MSD）和扩散系数等参数，以研究乙二醇在不同温度（270.15 K - 300 K）和浓度（0 - 15% V/V）下的影响。结果表明，随着温度的升高，气体解离加速150%，使甲烷更快地逸出到模拟箱中，从而实现了可控的产气。此外，乙二醇浓度增加10%会使水合物结构不稳定。基于这些发现，我们推荐使用10% v/v的乙二醇在280.15 K下解离天然气水合物。

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引用次数: 0

Pressure-driven wettability evolution and multiscale capillary sealing during CO2 penetration into mudstone caprocks 泥岩盖层CO2渗透过程的压力驱动润湿性演化与多尺度毛细密封

IF 4.6 0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2026-05-01 Epub Date: 2026-01-28 DOI: 10.1016/j.geoen.2026.214384

Liyun Tao , Jinchang Sheng , Huimin Wang , Muhammad ishfaque , Xiaolong Yuan , Yulong Luo

During CO₂ penetration into the mudstone caprock, partial CO₂ dissolution and interactions with brine alter the mudstone's wettability. This alteration controls the two-phase flow process, ultimately affecting caprock sealing efficiency. Although previous studies have recognized wettability alterations during CO₂ displacement, the influence of CO₂-brine-rock interactions as well as the evolution of pore structure under varying pressure gradients on wettability alteration remain unclear. Therefore, this study employed nuclear magnetic resonance (NMR) coupled with real-time seepage apparatus to conduct CO₂-brine displacement experiments under different flow rates to investigate the mechanism of wettability alteration. First, two-dimensional (2D) T₁-T₂ NMR was used to quantitatively characterize the time-dependent evolution of mudstone wettability under different injection rates. Subsequently, the effects of CO₂-brine-mineral physicochemical interactions on wettability evolution were analyzed. Finally, the evolution of capillary pressure across multiscale pores and its influence on wettability alteration were investigated. Experimental results indicate that: (1) The increasing wettability index (from −0.7 to 0.7) and decreasing contact angle (from 150° to 30°) during CO₂ flooding suggests a transition toward hydrophilicity, enhancing the self-sealing capacity of the mudstone. (2) Potassium feldspar transformed to kaolinite as well as dolomite dissolution, thus enhancing hydrophilicity. (3) Under high CO₂ flooding pressure, enhanced hydrophilicity significantly increases capillary resistance in micropores, facilitating residual CO₂ trapping and sealing efficiency.

在CO2渗透泥岩盖层的过程中，部分CO2溶解以及与盐水的相互作用改变了泥岩的润湿性。这种蚀变控制了两相流过程，最终影响了盖层的密封效率。虽然前人的研究已经认识到CO2驱替过程中润湿性的变化，但CO2-盐水-岩石相互作用以及不同压力梯度下孔隙结构的演化对润湿性变化的影响尚不清楚。因此，本研究采用核磁共振（NMR）结合实时渗流仪进行不同流速下co2 -盐水驱替实验，探讨润湿性改变的机理。首先，利用二维（2D） T1-T2核磁共振定量表征了不同注入速率下泥岩润湿性随时间的演化特征。分析了co2 -盐水-矿物物理化学相互作用对润湿性演化的影响。最后，研究了多尺度孔隙中毛细压力的演化及其对润湿性变化的影响。实验结果表明：(1)CO2驱过程中，泥岩的润湿性指数从- 0.7增加到0.7，接触角从150°减小到30°，表明泥岩向亲水性过渡，增强了泥岩的自封闭能力。(2)钾长石向高岭石和白云石转化，增强了亲水性。(3)在高CO2驱油压力下，亲水性的增强显著提高了微孔中的毛细阻力，有利于残余CO2的捕集和密封效率。

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引用次数: 0

Feasibility assessment of high-temperature aquifer thermal energy storage using design of experiments 利用实验设计评价高温含水层蓄热的可行性

IF 4.6 0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2026-05-01 Epub Date: 2026-02-03 DOI: 10.1016/j.geoen.2026.214393

Mohammad Khasheei , Jakob Kulich , Richard Scholey , Gregor Götzl , Keita Yoshioka

Thermal energy storage technologies can mitigate the seasonal imbalance of the heating and cooling supply. Among these, Aquifer Thermal Energy Storage (ATES) is particularly promising because of its small surface footprint and large subsurface storage capacity. However, its performance assessment is affected by uncertainties in subsurface properties and operational conditions. This poses challenges for decision- making. Moreover, systematic and computationally efficient uncertainty quantification frameworks for high-temperature ATES systems remain rare, particularly for sites with limited prior data. While Monte Carlo simulations are commonly used to address these uncertainties, their computational cost can become prohibitively high when hydrological simulators are employed. To overcome this challenge, this study presents a Design of Experiments based workflow. The workflow includes parameter screening to identify the most influential variables on ATES performance and the development of a surrogate model to enable efficient Monte Carlo simulations. Such workflows are widely applied in the oil and gas industry for field development and uncertainty quantification. However, their use in the context of ATES remains limited. The entire workflow is integrated into a fully automated Python script and was tested using data from the southern Vienna Basin, Austria, which represents an uninvestigated greenfield site for ATES development. Results from the screening step identify injection temperature at the hot well, total circulating water volume, thermal gradient, and longitudinal dispersivity as the most influential factors. Monte Carlo simulation results indicate that, given the uncertainty ranges considered, the most probable values for the Heat Recovery Factor and gross heat production in winter are 0.89 and 19.03 GWh.

蓄热技术可以缓解供热和制冷供应的季节性不平衡。其中，含水层热能储存（ATES）因其占地面积小，地下储存容量大而特别有前景。然而，其性能评估受到地下性质和操作条件的不确定性的影响。这对决策提出了挑战。此外，用于高温ATES系统的系统和计算效率高的不确定性量化框架仍然很少，特别是对于先前数据有限的站点。虽然蒙特卡罗模拟通常用于解决这些不确定性，但当使用水文模拟器时，其计算成本可能会变得过高。为了克服这一挑战，本研究提出了一种基于实验的工作流设计。工作流程包括参数筛选，以确定对ATES性能影响最大的变量，并开发代理模型，以实现高效的蒙特卡罗模拟。这种工作流程广泛应用于油气行业的油田开发和不确定性量化。然而，它们在ATES环境中的使用仍然有限。整个工作流程集成到一个全自动Python脚本中，并使用来自奥地利维也纳盆地南部的数据进行了测试，该盆地代表了一个未经调查的ATES开发绿地。筛选结果表明，热井注入温度、循环水总量、热梯度和纵向分散度是影响热井渗透率的主要因素。蒙特卡罗模拟结果表明，在考虑不确定性范围的情况下，冬季热回收系数和总产热量的最可能值分别为0.89和19.03 GWh。

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引用次数: 0

Synthesis and performance optimization of low-viscosity polymeric retarding agent with dual adsorption layers for acid fracturing 双吸附层酸压裂低粘度高分子缓凝剂的合成及性能优化

IF 4.6 0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2026-05-01 Epub Date: 2026-02-01 DOI: 10.1016/j.geoen.2026.214398

Chong Lin , Jianglong Tan , Heng Zhang , Jincheng Mao , Yang Zhang , Xiaojiang Yang

To address the issues of excessively rapid acid-rock reaction rates, difficulties in spent acid flowback, and severe secondary damage during acid fracturing operations, a dual-adsorption low-viscosity retarding agent (GL-A) was successfully synthesized through free radical aqueous polymerization in this study. The retarding agent was prepared using methacryloxyethyl trimethyl ammonium chloride (DMC), acrylamide (AM), dimethyl diallyl ammonium chloride (DMDAAC), octadecyl dimethyl allyl ammonium chloride (DMAAC-18), and perfluorooctyl ethyl acrylate (PFOA) as raw materials, with optimal synthesis conditions determined through single-factor optimization. The successful synthesis of the target polymer was confirmed by fourier transform infrared spectroscopy and nuclear magnetic resonance analyses. It is demonstrated that when the retarding agent dosage reaches 0.7 wt%, optimal retardation efficiency is achieved while low apparent viscosity characteristics of 15 mPa s are maintained, with superior film-forming retardation effects shown compared to conventional retarding agents (e.g., GL-B). Through comprehensive analysis using x-ray photoelectron spectroscopy, laser particle size analysis, scanning electron microscopy, infrared spectroscopy of rock surface substances, and contact angle measurements. It was revealed that a dual adsorption film is formed by GL-A on rock surfaces during acid-rock reactions: the first layer is anchored through electrostatic adsorption by carbon chains, while the second layer achieves dense coverage via strong hydrophobicity of fluorine chains. New insights are provided by the proposed dual-adsorption retardation mechanism for developing low-viscosity high-efficiency acidizing technologies. The operational challenges of traditional thickened acids related to pumping difficulties and reservoir damage caused by spent acid flowback are effectively resolved by the low-viscosity characteristic.

为了解决酸岩反应速率过快、废酸返排困难以及酸压裂作业中二次损伤严重等问题，本研究通过自由基水溶液聚合成功合成了双吸附低粘度缓凝剂（GL-A）。以甲基丙烯氧乙基三甲基氯化铵（DMC）、丙烯酰胺（AM）、二甲基二烯丙基氯化铵（DMDAAC）、十八烷基二甲基烯丙基氯化铵（DMAAC-18）、丙烯酸全氟辛基乙酯（PFOA）为原料制备了缓凝剂，通过单因素优化确定了最佳合成条件。通过傅里叶变换红外光谱和核磁共振分析证实了目标聚合物的成功合成。结果表明，当缓凝剂用量达到0.7 wt%时，缓凝效率达到最佳，同时保持15 mPa s的低表观粘度特性，与常规缓凝剂（如GL-B）相比，缓凝效果更好。通过x射线光电子能谱、激光粒度分析、扫描电镜、红外光谱对岩石表面物质进行综合分析，并对接触角进行测量。结果表明，在酸岩反应过程中，GL-A在岩石表面形成双重吸附膜：第一层通过碳链的静电吸附锚定，而第二层通过氟链的强疏水性实现密集覆盖。本文提出的双吸附缓速机理为开发低粘度高效酸化技术提供了新的思路。传统稠化酸的低粘度特性有效解决了泵送困难和废酸返排造成的储层损害等作业难题。

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引用次数: 0

Low salinity water - engineered microsphere injection for in-depth conformance control in permeable carbonates: an experimental study 低矿化度水工程微球注入用于渗透性碳酸盐岩的深度控制：实验研究

IF 4.6 0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2026-05-01 Epub Date: 2026-02-09 DOI: 10.1016/j.geoen.2026.214419

Dongqing Cao , Subhash Ayirala , Salah Saleh , Ghaida Aljuhani

Low salinity water (LSW) - engineered microsphere injection presents a promising hybrid technique for in-depth conformance control in permeable carbonate reservoirs. However, the process faces significant challenges due to the complex interactions between microspheres and saline brines, especially at high temperature and high salinity conditions. This study investigated the flow and oil recovery performance of this hybrid process within carbonate porous media to elucidate the synergistic effects through coreflooding tests at reservoir temperature 95 °C and pore pressure 3100 psi. Results showed that the migration/blocking performances of microsphere in cores were sensitive to brine salinity particularly at elevated temperature due to weak zeta potential. While microspheres swelled as salinity decreased, those dispersed in conventional high salinity injection water generated much higher differential pressure when injected into brine-saturated carbonate cores than in LSW. Merely mixing microspheres with LSW was insufficient from blocking point of view. Instead, a two-step approach was proposed where microspheres dispersed in conventional injection water (CIW) were first injected, followed by low salinity water injection. Single-phase flow tests demonstrated that this approach produced sufficient blocking in high-permeability carbonate core plugs. The LSW further enhanced blocking and mitigated high retention of microsphere caused by poor dispersibility in high salinity water. Oil displacement test confirmed the blocking capabilities of this method in the presence of oil. The incremental oil recovery by this method reached 8.3% after a bump water flooding that was much higher than LSW alone injection, indicating effective synergistic effects between microspheres and LSW.

低矿化度水（LSW）微球注入技术是一种很有前途的混合技术，可用于渗透碳酸盐岩储层的深度控制。然而，由于微球与盐水之间复杂的相互作用，特别是在高温和高盐度条件下，该工艺面临着重大挑战。本研究通过在储层温度95°C、孔隙压力3100 psi条件下的岩心驱油试验，研究了碳酸盐多孔介质中该混合过程的流动和采收率，以阐明协同效应。结果表明，岩心中微球的运移/封堵性能对盐水盐度敏感，特别是在温度升高时，由于zeta电位较弱。当微球随着矿化度的降低而膨胀时，那些分散在常规高矿化度注入水中的微球在注入饱和盐水的碳酸盐岩心时产生的压差要比LSW高得多。从阻挡的角度来看，仅仅将微球与LSW混合是不够的。相反，提出了一种两步法，首先注入分散在常规注入水中的微球，然后注入低矿化度的水。单相流测试表明，这种方法在高渗透率碳酸盐岩心桥塞中产生了足够的封堵效果。LSW进一步增强了堵塞，减轻了微球在高盐度水中由于分散性差而造成的高滞留。驱油试验证实了该方法在有油情况下的封堵能力。该方法经凸水驱后的原油增量采收率达到8.3%，远高于单独注入LSW，表明微球与LSW之间存在有效的协同效应。

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引用次数: 0

Pillar safety analysis and layout optimization for hydrogen storage cavern groups in bedded salt formations — A study based on thermal-hydraulic-mechanical (THM) coupling 层状盐层储氢洞穴群矿柱安全性分析及布局优化——基于热-液-力耦合的研究

IF 4.6 0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2026-05-01 Epub Date: 2026-02-09 DOI: 10.1016/j.geoen.2026.214417

Xiao Wang , Guimin Zhang , Jingjiang Li , Mingnan Xu , Yashuai Huang , Yuxuan Liu , Si Huang , Long Chen , Yang Hong , Xiaoyi Liu , Xilin Shi , Yinping Li

Salt cavern hydrogen storage is regarded as a significant development direction for large-scale hydrogen energy storage. Compared to other stored gases such as natural gas or compressed air, hydrogen exhibits characteristics such as smaller molecular size, lower dynamic viscosity, and higher chemical reactivity, which could potentially impact the stability of surrounding rock, particularly cavern pillars, through seepage. Furthermore, the high-frequency and high-intensity injection-withdrawal cycles of hydrogen result in greater thermal disturbances to the storage cavern compared with natural gas. Accordingly, a thermo–hydro–mechanical (THM) coupling model is developed to quantitatively elucidate the magnitude and spatial extent of the effects of hydrogen seepage, injection–withdrawal–induced temperature fluctuations, and surrounding rock stress on the safety of cavern group pillars. Additionally, based on these findings, the layout scheme of the hydrogen storage cavern group was optimized. The main conclusions drawn are as follows: Hydrogen seepage has a non-negligible influence on cavern pillars, leading to a reduction in the strength of surrounding rocks, particularly interlayers; although the thermal disturbance from hydrogen injection-withdrawal cycles causes temperature redistribution within surrounding rock, its impact range is limited, posing no significant threat to pillar safety; the hard interlayers represent the main damaged zones within cavern pillars, and seepage further reduces their strength, thus these interlayers require special attention in engineering practice; under the condition of equal resource utilization for a single salt cavern, adopting a parallelogram layout results in improved pillar stability within the hydrogen storage cavern group. The results from this research can provide a useful reference for large-scale hydrogen energy storage.

盐穴储氢被认为是大规模储氢的重要发展方向。与天然气或压缩空气等其他储存气体相比，氢气具有分子尺寸更小、动态粘度更低、化学反应性更高的特点，这可能会通过渗透影响围岩的稳定性，尤其是洞穴柱的稳定性。此外，与天然气相比，氢气的高频和高强度注入-提取循环对储洞的热扰动更大。在此基础上，建立了热-水-力耦合模型，定量分析了氢渗流、注回采温度波动和围岩应力对洞室群矿柱安全的影响程度和空间范围。并在此基础上对储氢洞室组的布置方案进行了优化。主要结论如下：氢渗流对洞室矿柱有不可忽视的影响，导致围岩特别是夹层强度降低；注回采氢循环产生的热扰动虽然引起围岩内部温度重分布，但其影响范围有限，对矿柱安全不构成显著威胁；硬夹层是洞室柱内部的主要破坏区域，渗流会进一步降低其强度，因此在工程实践中需要特别注意；在单个盐洞资源利用均等的情况下，采用平行四边形布局可以提高储氢洞群内矿柱的稳定性。研究结果可为大规模储氢提供有益的参考。

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引用次数: 0

Research on gas diffusion laws of CO2 injection in acidic gas reservoirs within slit pores based on molecular dynamics simulation 基于分子动力学模拟的缝状孔隙内酸性气藏CO2注入气体扩散规律研究

IF 4.6 0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2026-05-01 Epub Date: 2026-01-30 DOI: 10.1016/j.geoen.2026.214413

Xiao Guo , Zuohao Wang , Pengkun Wang , Zuwei Chen , Zhi Li , Lan Wang , Mingda Dong

Carbonate acidic gas reservoirs are widely distributed, and CO₂ injection can improve recovery and achieve carbon sequestration. Previous studies on acid gas diffusion in carbonate formations have largely overlooked the influence of micro- and nanoscale pore structures on interfacial tension and the nonlinear flow behavior of acidic gases at the microscopic scale. In this article, equilibrium molecular dynamics (EMD) simulations were employed to investigate the diffusion behavior of acidic gases in slit-shaped pores, taking into account the competitive adsorption characteristics of gas molecules. The effects of pore radius, gas composition, elemental sulfur content, reservoir mineral type, and water saturation on acid gas diffusion during CO₂ injection and depletion development in carbonate reservoirs were systematically analyzed. The study shows that the competitive adsorption mechanism within slit pores intensifies gas slippage and enhances the diffusion of weakly adsorbed gases. In addition, pore size has a greater influence on gas diffusion than gas composition and mineral type. When sulfur deposition occurs in the gas reservoir, the monomeric sulfur attached to the pore wall reduces the pore free space, and CH₄ can still form a smaller adsorption layer, with an effect on gas diffusion type of about 5 %. In order to reduce the loss of kinetic energy of gas molecules, the reservoir pressure should be higher than the diffusion type conversion pressure when CO₂ is injected, so that the sour gas is in the process of molecular diffusion. When the reservoir has a high water saturation, water molecules tend to condense into water bridges, significantly reducing gas diffusivity. This study provide theoretical basis for the efficient development of carbonate reservoirs and effective geological sequestration of CO₂.

碳酸盐岩酸性气藏分布广泛，注入CO2可提高采收率，实现固碳。以往的碳酸盐岩酸性气体扩散研究在很大程度上忽略了微纳米尺度孔隙结构对界面张力的影响以及微观尺度酸性气体的非线性流动行为。本文采用平衡分子动力学（EMD）模拟方法，考虑气体分子的竞争吸附特性，研究了酸性气体在狭缝状孔隙中的扩散行为。系统分析了碳酸盐岩储层注竭开发过程中孔隙半径、气体组成、单质硫含量、储层矿物类型、含水饱和度等因素对酸性气体扩散的影响。研究表明，狭缝孔隙内的竞争吸附机制加剧了气体的滑移，增强了弱吸附气体的扩散。此外，孔隙大小对气体扩散的影响大于气体成分和矿物类型。当气藏中发生硫沉积时，附着在孔壁上的单体硫使孔隙自由空间减小，CH4仍能形成较小的吸附层，对气体扩散类型的影响约为5%。为了减少气体分子动能的损失，在注入CO2时，储层压力应高于扩散型转化压力，使酸性气体处于分子扩散过程中。当储层含水饱和度高时，水分子倾向于凝结成水桥，显著降低气体的扩散系数。该研究为碳酸盐岩储层的高效开发和二氧化碳的有效地质封存提供了理论依据。

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引用次数: 0

Permeability evolution and heat transfer in hot sedimentary aquifers and enhanced geothermal systems: Insights from coupled DFN-THM modeling 热沉积含水层和增强型地热系统的渗透率演化和传热：来自耦合ddn - thm模型的见解

IF 4.6 0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2026-05-01 Epub Date: 2026-02-04 DOI: 10.1016/j.geoen.2026.214387

Yueqiang Ma , Ying Li , Quan Gan

Hot Sedimentary Aquifers (HSA) and Enhanced Geothermal Systems (EGS) represent two important geothermal resources with distinct geological and mechanical characteristics. Understanding their permeability evolution and heat transfer behavior is critical for assessing reservoir performance and guiding engineering design. In this study, a discrete fracture network (DFN) model coupled with thermo-hydro-mechanical (THM) processes is developed to investigate the contrasting response of HSA and EGS under varying stress states, pore pressures, fracture densities, reservoir temperatures, and intrinsic permeabilities. The results show that fracture aperture evolution is initially dominated by normal closure, whereas shear dilation becomes significant once stresses reach the Coulomb failure criterion. Compared to EGS, the higher fracture density in HSA leads to larger cumulative apertures and higher heat extraction efficiency. Quantitative analysis indicates that fracture density strongly controls thermal propagation, with a critical range where heat transfer efficiency increases rapidly. Reservoir temperature and permeability further regulate fracture sensitivity, with EGS showing greater stress- and temperature-dependent variability than HSA. These findings highlight the fundamental differences in fluid–heat–mechanical coupling between HSA and EGS. The insights gained provide practical implications for geothermal energy development, including optimizing well placement, fracture stimulation strategies, and reservoir management to enhance long-term sustainability.

热沉积含水层（HSA）和增强型地热系统（EGS）是两种重要的地热资源，具有不同的地质和力学特征。了解储层的渗透率演化和传热行为对评价储层动态和指导工程设计具有重要意义。在这项研究中，建立了一个离散裂缝网络（DFN）模型，结合热-水-力学（THM）过程，研究了不同应力状态、孔隙压力、裂缝密度、储层温度和固有渗透率下HSA和EGS的对比响应。结果表明：裂缝孔径演化初期以法向闭合为主，当应力达到库仑破坏准则时，剪切扩张开始显著；与EGS相比，HSA中较高的裂缝密度导致了更大的累积孔径和更高的排热效率。定量分析表明，断口密度对热传导有很强的控制作用，存在一个传热效率迅速提高的临界范围。储层温度和渗透率进一步调节裂缝敏感性，EGS比HSA表现出更大的应力和温度依赖性。这些发现突出了HSA和EGS在流体-热-机械耦合方面的根本差异。所获得的见解为地热能源开发提供了实际意义，包括优化井位、压裂增产策略和油藏管理，以提高长期可持续性。

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引用次数: 0

Evaluating subsea-capping-stack usage for CO2 blowouts 评估海底封顶装置对二氧化碳井喷的使用情况

IF 4.6 0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2026-05-01 Epub Date: 2026-01-29 DOI: 10.1016/j.geoen.2026.214412

Lei Zhou , Eric R. Upchurch , Yaxin Liu , Bjoern-Tore Anfinsen , Yahya Hashemian , Zhaoguang Yuan

This study evaluates the suitability of using existing subsea capping stack (SCS) designs to control CO₂ blowouts. The physics behind controlling a methane (i.e., CH₄) subsea blowout using an SCS is well understood by the oil and gas industry. The same, however, is not true for CO₂, whose thermophysical properties differ greatly from CH₄. Hence, the risks associated with halting a CO₂ blowout with an SCS are not clearly understood. Understanding such risks, though, is an indispensable step in preparing for the future possibility of a subsea CO₂ blowout.

Numerical simulations of blowout/SCS scenarios for various combinations of water depth (300 or 762 m), blowout rate (4.25, 8.93 or 10.49 MMm³/d), reservoir fluid (CO₂ or CH₄), and SCS configuration (three variants) are conducted, with the goal of generating a broad spectrum of results for understanding the differences between installing an SCS on CO₂ versus CH₄ blowouts. Each simulation covers the full progression of a blowout (from initial reservoir fluid influx to final closure of the SCS). Multiphase computational fluid dynamic (CFD) modeling of the entire sequence is performed using a version of the OLGA model, newly applied to CO₂ well-control events.

High-rate CO₂ blowouts in shallow water create conditions conducive to significant hydrate and ice formation, whereas CH₄ blowouts do not (under any condition). The configuration of an SCS has little impact on outcomes. This suggests that using an SCS to control a shallow-water, high-rate CO₂ blowout may encounter difficulties, implying that relief wells may be a necessary back-up option.

本研究评估了使用现有海底封顶装置（SCS）设计来控制二氧化碳井喷的适用性。油气行业对利用SCS控制海底甲烷（即CH4）井喷背后的物理原理非常了解。然而，二氧化碳的情况并非如此，它的热物理性质与CH4大不相同。因此，用SCS阻止二氧化碳井喷的相关风险尚不清楚。然而，了解这些风险是为未来可能发生的海底二氧化碳井喷做好准备必不可少的一步。对不同水深（300或762米）、井喷速率（4.25、8.93或10.49 MMm3/d）、储层流体（CO2或CH4）和SCS配置（三种变体）的井喷/SCS方案进行了数值模拟，目的是产生广泛的结果，以了解在CO2和CH4井喷中安装SCS的差异。每次模拟都涵盖了井喷的整个过程（从最初的油藏流体流入到最终关闭SCS）。整个序列的多相计算流体动力学（CFD）建模使用OLGA模型的一个版本，新应用于CO2井控事件。在浅水中，高速率的CO2井喷创造了有利于大量水合物和冰形成的条件，而CH4井喷则没有（在任何条件下）。SCS的配置对结果影响不大。这表明，使用SCS来控制浅水、高速率的二氧化碳井喷可能会遇到困难，这意味着减压井可能是必要的备用选择。

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引用次数: 0

Microscopic reactive dynamics of CO2-brine-carbonate systems: Insights into pores, fractures and vugs co2 -盐水-碳酸盐岩体系的微观反应动力学：对孔隙、裂缝和溶洞的洞察

IF 4.6 0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2026-05-01 Epub Date: 2026-02-03 DOI: 10.1016/j.geoen.2026.214390

Yulong Zhao , Rui Tang , Tao Zhang , Yongchao Wang , Shaomu Wen , Zihan Zhao , Zhenglin Cao , Wei Xiong , Hailiang Liu , Ali Hassanpouryouzband , Hung Vo Thanh , Liehui Zhang

The injection of supercritical CO₂ into water-bearing carbonate reservoirs disrupts chemical equilibrium, inducing dissolution, precipitation, and particle migration that modify reservoir properties. Carbonate rocks have diverse storage spaces, including pores, fractures, and vugs. This study investigated the microscopic mechanisms of CO₂-saturated brine interacting with different pore-network structure rocks. CO₂-saturated brine injection experiments were conducted at 40 °C and 10 MPa on pore-type, fracture-pore-type, and vuggy-type carbonate cores. X-ray CT captured dynamic structural changes, while SEM coupled with EDS and IC tracked precipitation and fluid chemistry at various reaction times. Results show that carbonate dissolution dominates, increasing porosity (vuggy > fracture-pore > pore-type). Permeability changes fluctuate: it increases in fracture-pore and vuggy samples but decreases in pore-type samples. Fractures and vugs mitigate precipitation effects on permeability. Dissolution mainly occurs in small pores, whereas large pores, fractures, and vugs experience minor dissolution, though dissolution near these features is pronounced. Precipitation increases from inlet to outlet, with less accumulation around fractures and vugs. These findings offer insights into CO₂ sequestration and enhanced gas recovery in water-bearing carbonate reservoirs with different pore-network structures.

向含水碳酸盐岩储层注入超临界二氧化碳会破坏化学平衡，导致溶解、沉淀和颗粒迁移，从而改变储层的性质。碳酸盐岩具有多种储集空间，包括孔隙、裂缝和溶洞。研究了饱和co2盐水与不同孔隙网络结构岩石相互作用的微观机制。在40℃、10 MPa条件下，对孔隙型、缝孔型和洞型碳酸盐岩岩心进行了饱和co2注盐水实验。x射线CT捕获了动态结构变化，而SEM与EDS和IC结合跟踪了不同反应时间的沉淀和流体化学。结果表明：碳酸盐岩溶蚀作用占主导地位，孔隙度增大（孔洞型）；渗透率呈波动变化，缝孔型和孔洞型样品渗透率增大，孔型样品渗透率减小。裂缝和孔洞减轻了降水对渗透率的影响。溶蚀主要发生在小孔隙中，而大孔隙、裂缝和溶洞则发生少量溶蚀，但这些特征附近的溶蚀作用明显。降水从入口到出口增加，裂缝和孔洞周围的积累较少。这些发现为研究具有不同孔隙网络结构的含水碳酸盐岩储层的CO2封存和提高采收率提供了新的思路。

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引用次数: 0