Geoenergy Science and Engineering最新文献_第4页

Influence of fracture network characteristics of hot dry rock on heat extraction performance: A numerical simulation study 干热岩石的断裂网特征对热萃取性能的影响：数值模拟研究

0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2024-11-17 DOI: 10.1016/j.geoen.2024.213523

Shijie Chen , Haiyan Zhu , Peng Zhao , Yanyong Wang , Rongcai Song , Yinhui Zuo , Yu Shi , Tao Zhou

Considering the many hot dry rock (HDR) fields in China, efficient development of geothermal energy is an effective means to achieve carbon neutrality and net zero carbon emissions. Enhancing the heat exchange efficiency of the geothermal reservoir fracture network is an effective method for realizing the beneficial development of HDR resources. To analyze the influence of the characteristics of fracture network on the heat recovery performance of HDR, this study examines the coupling relationships among various physical fields and develops a thermal-fluid-solid multi-field coupling numerical simulation method that incorporates the effects of low-temperature and evolution of rock matrix permeability. Furthermore, the established model was verified using the thermal-coupled theoretical solution, experiment, and monitoring data from the Hijiori field. Based on these findings, a THM coupled injection-production heat transfer model, considering the characteristics of the fracture network in the Gonghe Basin of Qinghai Province, was developed. The influence of fracture network on geothermal development was then systematically analyzed. The results indicate that increased number of fractures and wider fracture spacing are more conducive to improving heat extraction performance. The dominant channel reduces heat transfer efficiency in surrounding fractures. Besides, when the width of the dominant channel is more than 2 mm, there is a double increase in the ratio of the dominant channel width to the width of fractures in the heat transfer zone. Overall, the impact of the dominant channel is evident after low-temperature fluid injection over time. The characteristics of the fracture network, especially the dominant channels, are critical for designing geothermal exploitation strategies in HDR systems.

中国干热岩（HDR）资源丰富，高效开发地热能是实现碳中和与碳净零排放的有效途径。提高地热储层断裂网的热交换效率是实现干热岩资源效益开发的有效方法。为了分析断裂网特征对 HDR 热回收性能的影响，本研究研究了各种物理场之间的耦合关系，并开发了一种热-流-固多场耦合数值模拟方法，该方法结合了低温和岩石基质渗透率演化的影响。此外，还利用热耦合理论解、实验和 Hijiori 油田的监测数据对所建立的模型进行了验证。在此基础上，考虑到青海省共和盆地断裂网的特点，建立了 THM 注采耦合传热模型。然后系统分析了断裂网对地热开发的影响。结果表明，增加断裂数量和加宽断裂间距更有利于提高采热性能。优势通道会降低周围断裂的传热效率。此外，当主导通道宽度大于 2 毫米时，传热区内主导通道宽度与裂缝宽度之比会成倍增加。总之，低温流体注入后，随着时间的推移，主导通道的影响是显而易见的。断裂网络的特征，尤其是优势通道的特征，对于设计 HDR 系统的地热开发战略至关重要。

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引用次数: 0

Experimental study of optimized injection schemes for enhanced gas recovery and carbon sequestration 强化天然气回收和碳封存的优化注入方案实验研究

0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2024-11-17 DOI: 10.1016/j.geoen.2024.213508

Shezhan Liu , Yi Zhang , Lei Yuan , Siyu Xu , Lanlan Jiang , Yuechao Zhao , Yongchen Song

To reduce the carbon capture costs in CO₂ enhanced gas recovery (EGR) process, three types of displacing fluids, pure CO₂, flue gas and gas-altering gas, were used in the conventional injection mode for experimental comparison. It was found that pure CO₂ had the highest recovery efficiency and the smallest dispersion coefficient at supercritical state. The dispersion coefficients of the three displacing fluids became larger with increasing water saturation. The optimized EGR injection schemes were proposed, in which the first stage was displaced by N₂ or CO₂ mixtures as booster gas, while the second stage was displaced by CO₂ to improve CH₄ recovery and CO₂ sequestration efficiency as well as to reduce CO₂ capture costs. Both N₂ and flue gas were found to perform well as booster gas in the gaseous state. The highest CH₄ recovery efficiency of 36.05% and the highest CO₂ sequestration efficiency of 21.31% were obtained for N₂ as booster gas in dry rock core due to the overall improved sweep efficiency and the barricade effect of N₂. Whereas, the flue gas as booster gas had better performance under supercritical conditions with the highest recovery efficiency of 36.69%. In addition, it was found that the dispersion coefficients of the optimized injection schemes became larger due to the pipeline entry/exit effects. Due to the dissolution of CO₂ into connate water, the optimized scheme had the best results in CH₄ recovery and CO₂ sequestration with flue gas as the booster gas, improving by 20.5% and 13.5%, respectively, compared to the conventional CO₂ injection scheme.

为降低二氧化碳强化气体回收（EGR）工艺中的碳捕集成本，在常规注入模式下，使用了纯二氧化碳、烟道气和改气气体三种置换流体进行实验比较。结果发现，在超临界状态下，纯 CO2 的回收效率最高，分散系数最小。三种置换流体的分散系数随着水饱和度的增加而变大。提出了优化的 EGR 喷射方案，其中第一阶段用 N2 或 CO2 混合物作为增压气体进行置换，第二阶段用 CO2 进行置换，以提高 CH4 回收率和 CO2 封存效率，并降低 CO2 捕获成本。作为气态增压气体，N2 和烟道气的性能都很好。在干燥岩芯中，N2 作为增压气体的 CH4 回收效率最高，达到 36.05%，CO2 封存效率最高，达到 21.31%，这主要归功于 N2 全面提高的扫气效率和屏障效应。而烟道气作为增压气体在超临界条件下性能更好，回收效率最高，达到 36.69%。此外，研究还发现，由于管道出入口效应，优化注入方案的分散系数变大。由于二氧化碳溶解到涵养水中，以烟道气为增压气体的优化方案在甲烷回收和二氧化碳封存方面效果最佳，与传统的二氧化碳注入方案相比，分别提高了 20.5% 和 13.5%。

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引用次数: 0

A new insight into the breakup distance and capillary pressure of liquid bridges formed in rough fractures 对粗糙裂缝中形成的液桥的断裂距离和毛细管压力的新认识

0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.geoen.2024.213514

Reza Sedaghatinasab, Mohammad Hossein Ghazanfari

The formation of a liquid bridge between two adjacent surfaces has a crucial role in many industrial and scientific applications, such as waste disposal management, granular materials, and flow through fractured porous media. Despite numerous studies, the understanding of how the stability and capillary pressure of liquid bridges formed in rough fractures may controlled by the geometrical properties of fracture surface roughness has received limited attention. In this study, a natural fracture profile of a subsurface carbonate rock is analyzed and the geometrical properties of cone-plate roughness models are extracted. Combined with the numerical solution of the Young-Laplace capillarity equation, the liquid bridge capillary pressure and breakup distance in the rough fracture systems are characterized, and more realistic data of fracture capillary pressure and breakup distance of liquid bridges are provided. The results show that increasing the roughness height causes the breakup distance of liquid bridge increases, while the capillary pressure decreases. When, the liquid volume in the fracture is less than 5% and the fracture width is sufficiently thin (<0.2

m m

), the liquid bridge capillary pressure is as high as 14

K P a

, which is a significant value. In the context of natural fractured reservoirs, where fractures possess different widths and roughness characteristics, a new generalized capillary pressure model is developed, which enables the estimation of capillary pressure for liquid bridges formed in rough-walled fractures. The capillary pressure data of rough fractures presented in this work, may fill a gap in the literature and providing required information for simulating oil recovery in fractured reservoirs.

在两个相邻表面之间形成液桥在许多工业和科学应用中都起着至关重要的作用，如废物处理管理、颗粒材料和流经断裂多孔介质。尽管进行了大量研究，但人们对粗糙断裂中形成的液桥的稳定性和毛细管压力如何受断裂表面粗糙度的几何特性控制的了解还很有限。本研究分析了地下碳酸盐岩的天然断裂剖面，并提取了锥板粗糙度模型的几何特性。结合杨-拉普拉斯毛细管方程的数值求解，对粗糙断裂体系中的液桥毛细管压力和断裂距离进行了表征，并提供了更为真实的断裂毛细管压力和液桥断裂距离数据。结果表明，粗糙度高度增加会导致液桥破裂距离增大，而毛细管压力减小。当裂缝中的液体体积小于 5%，且裂缝宽度足够薄（0.2 mm）时，液桥毛细管压力高达 14 KPa，这是一个很重要的值。在天然裂缝储层中，裂缝具有不同的宽度和粗糙度特征，因此建立了一个新的广义毛细管压力模型，可以估算粗糙壁裂缝中形成的液桥的毛细管压力。这项工作中提出的粗糙裂缝毛管压力数据可以填补文献空白，为模拟裂缝储层采油提供所需的信息。

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引用次数: 0

Microscale multiphase oil displacement simulation and experimental study based on microfluidics approach 基于微流控方法的微尺度多相油置换模拟与实验研究

0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.geoen.2024.213529

Jianshan Li , Xiao Qu , Xiaobing Lu , Li'an Yang , Bitao Wang , Yiqiang Fan

Oil exists in the underground formation in the form of tiny droplets trapped inside the pores. Pores have a diversity of shapes, uneven pore distribution, and unstable fluid status in the reservoir, and all these complexities have brought great challenges to crude oil displacement and recovery in the oil industry. The crude oil displacement process and mechanism at the micro-scale or even nano-scale have been a hot research spot in the recent decade. With the rapid development of microfluidics techniques in biological and medical fields with the unique advantage of precise liquid handling, researchers have started to use microfluidics for direct visual observation and manipulation of tertiary oil recovery. And microfluidics method helps to deeply explore the underly complex displacement mechanism of crude oil at the micro or nano-scale. This study used the simulation and experimental method for the study of foam flooding on oil recovery with the help of microfluidics technique. This study first built the mathematical model and simulated the foam flow in porous media with finite element analysis, and then prepared a PDMS microfluidic chip with the soft lithography method. In the experimental process, the foam flooding and displacement process can be visually observed with the transparent microfluidic chips, and the detailed foam flooding process was analyzed and compared with the simulation result. Also, in the experimental process, we confirmed that compared with the displacement process of crude oil with saline, foam can effectively improve the oil displacement efficiency. This study helps to reveal the mechanism of micro-scale foam flooding and displacement process in the reservoir to improve the oil recovery efficiency in the oil production process.

石油以微小液滴的形式存在于地下油层的孔隙中。孔隙形状多样、孔隙分布不均、储层中流体状态不稳定，这些复杂性给石油工业中的原油驱替和采收带来了巨大挑战。微米甚至纳米尺度的原油置换过程和机理是近十年来的研究热点。随着微流控技术在生物和医学领域的快速发展，凭借其精确处理液体的独特优势，研究人员开始利用微流控技术对三次采油进行直接的可视化观察和操作。而微流控技术有助于在微米或纳米尺度上深入探索原油复杂位移的内在机理。本研究采用模拟和实验方法，借助微流控技术研究泡沫淹没对石油采收率的影响。研究首先建立了数学模型，利用有限元分析模拟了泡沫在多孔介质中的流动，然后利用软光刻方法制备了 PDMS 微流控芯片。在实验过程中，利用透明的微流控芯片可以直观地观察到泡沫的泛起和位移过程，并对泡沫泛起的具体过程进行了分析，与模拟结果进行了对比。同时，在实验过程中，我们证实了与原油与盐水的置换过程相比，泡沫能有效提高石油的置换效率。这项研究有助于揭示微尺度泡沫在储层中的淹没和置换过程的机理，从而提高石油生产过程中的采油效率。

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引用次数: 0

Influence of salt and temperature on the rheological and filtration properties of cellulose Nanofiber/bentonite water-based drilling fluids 盐和温度对纤维素纳米纤维/膨润土水基钻井液流变和过滤特性的影响

0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.geoen.2024.213524

Muhammad Arqam Khan , Kaihe Lv , Jinsheng Sun , Haokun Shen , Yaxuan Zhang , Abdullahi Ahmed Noor , Shaine Mohammadali Lalji , Chaozheng Liu , Mei-Chun Li

Water-based drilling fluids (WBDFs) are popular due to their lower cost and superior environmental friendliness. The high thermal stability, high aspect ratio, and fiber-like structure of cellulose nanofibers (CNFs) have made them viable candidates for rheology and filtration modification in bentonite WBDFs (BT-WBDFs), because they can produce high levels of hydration and entanglement when dispersed in water, even at very low concentrations under harsh drilling condition. However, the rheology and filtration performance of CNF/BT-WBDFs in high temperature and high saline conditions remains largely unexplored. Herein, the influence of high temperature and high salt content on the rheological and filtration properties of CNF/BT-WBDFs was investigated. Two types of CNFs, i.e., TEMPO-mediated oxidized CNFs (T-CNFs) and mechanically disintegrated CNFs (M-CNFs) were applied. It was observed that the M-CNFs exhibited more effectiveness in enhancing the rheological properties of BT-WBDFs, while T-CNFs demonstrated superior filtration-reducing properties of BT-WBDFs. M-CNFs often exhibit a highly branched and tangled network, resulting in superior rheological properties; whereas the presence of more negative charge on the surface of T-CNFs enhanced the electrostatic repulsion with bentonite particles, preventing bentonite from flocculating or aggregating, resulting in reduced fluid loss. Furthermore, the T-CNF/BT-WBDFs showed better resistance to salt contamination compared to hot rolling, whereas the M-CNF/BT-WBDFs demonstrated better defense against hot rolling than salt contamination. However, the addition of salt in combination with high-temperature hot rolling severely affected the rheological properties as well as the filtration-reducing capabilities of both T-CNF/BT- and M-CNF/BT-WBDFs. The study highlighted the importance of CNF types on the rheological and filtration properties of WBDFs under high temperature and saline conditions, providing valuable insights for the potential application of CNFs in temperature-resistant and salt-tolerant drilling fluids.

水基钻井液（WBDF）因其较低的成本和优越的环境友好性而广受欢迎。纤维素纳米纤维（CNFs）具有高热稳定性、高纵横比和纤维状结构，这使其成为膨润土水基钻井液（BT-WBDFs）流变和过滤改性的可行候选材料，因为即使在苛刻的钻井条件下浓度很低，它们分散在水中时也能产生高水平的水合和缠结。然而，CNF/BT-WBDFs 在高温和高盐度条件下的流变性和过滤性能在很大程度上仍未得到研究。本文研究了高温和高含盐量对 CNF/BT-WBDFs 流变和过滤性能的影响。应用了两种类型的 CNF，即 TEMPO 介导的氧化 CNF（T-CNF）和机械分解 CNF（M-CNF）。结果表明，M-CNFs 在增强 BT-WBDFs 流变特性方面更有效，而 T-CNFs 则在减少 BT-WBDFs 过滤方面表现优异。M-CNF 通常表现为高度支化和缠结的网络，因此流变性能优异；而 T-CNF 表面存在更多的负电荷，增强了与膨润土颗粒的静电斥力，防止膨润土絮凝或聚集，从而减少了流体损失。此外，与热轧相比，T-CNF/BT-WBDF 显示出更好的抗盐污染能力，而 M-CNF/BT-WBDF 则显示出比盐污染更好的抗热轧能力。然而，在高温热轧过程中添加盐会严重影响 T-CNF/BT 和 M-CNF/BT-WBDF 的流变特性和降滤能力。该研究强调了 CNF 类型对高温和含盐条件下 WBDF 的流变和过滤性能的重要影响，为 CNF 在耐温耐盐钻井液中的潜在应用提供了宝贵的启示。

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引用次数: 0

NMR relaxometry insights into pore-level sweep efficiency for methane infusion IOR in unconventional reservoirs 核磁共振弛豫测量法揭示非常规储层甲烷注入 IOR 的孔隙扫描效率

0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.geoen.2024.213527

Demetrius Maxey , Samuel Afari , Hadi Jabbari

Oil recovery factors (RF) remain under 10% in the major tight oil basins of the United States. This study examined the Charlotte 1–22H well in McKenzie County, North Dakota. Our study utilized nuclear magnetic resonance (NMR) logging to assess the methane infusion (MI) process as an improved oil recovery (IOR) method to mobilize oil at near-miscibility pressure. We propose a new nanoscale-centric method to characterize pore size distribution (PSD) based on our examination of T₂ relaxation time distribution. The authors used this methodology and its correlation with Field Emission Gun – Scanning Electron Microscope (FEG-SEM) imagery analysis to create the proposed PSD method, providing compatibility with nanoscale petrophysical analysis. In core samples, the T_{2_cutoff} pores sizes measured in UB-23 at 6.807 nm, MB-27 at 11.909 nm, and LB-44 at 3.253 nm. NMR relaxometry was used to study the pore-level sweep efficiency of methane infused into shale and tight formations. Variable infusion times allowed for a comparison of near-miscibility conditions per cycle with RFs of UB-23 at 60.78%, MB-27 at 42.97% and LB-44 at 45.18%. The RF of the infused hydrocarbon solution increased when interfacial tension (IFT) and viscosity were reduced. Additionally, the effects of rock-surface-to-volume ratio, soaking period, and their variable interactions with gas compositions were compared across the three core samples. The efficacy of MI at near-miscibility was substantial in all three core samples. The authors believe this research can serve as a foundation for a broader and more comprehensive study of MI as an effective IOR process.

美国主要致密油盆地的采油系数（RF）一直低于 10%。本研究考察了北达科他州麦肯齐县的夏洛特 1-22H 井。我们的研究利用核磁共振（NMR）测井来评估甲烷注入（MI）工艺，将其作为一种提高石油采收率（IOR）的方法，在接近混溶压力的条件下调动石油。我们根据对 T2 弛豫时间分布的研究，提出了一种以纳米尺度为中心的新方法来表征孔径分布 (PSD)。作者利用这种方法及其与场发射枪-扫描电子显微镜（FEG-SEM）图像分析的相关性创建了拟议的 PSD 方法，为纳米尺度岩石物理分析提供了兼容性。在岩心样品中，UB-23 的 T2_cutoff 孔隙尺寸为 6.807 nm，MB-27 为 11.909 nm，LB-44 为 3.253 nm。核磁共振弛豫测定法用于研究注入页岩和致密地层的甲烷的孔隙扫描效率。通过改变注入时间，可以比较每个周期的近混溶性条件，UB-23 的射频为 60.78%，MB-27 为 42.97%，LB-44 为 45.18%。当界面张力 (IFT) 和粘度降低时，注入碳氢化合物溶液的射频增加。此外，还比较了三个岩心样本的岩面体积比、浸泡时间及其与气体成分的不同相互作用的影响。在所有三个岩心样本中，MI 在接近混溶性时的效果都很显著。作者认为，这项研究可以为更广泛、更全面地研究 MI 作为一种有效的 IOR 工艺奠定基础。

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引用次数: 0

Performance characterization of wellbore cement containing different CO2-resisting additives under geologic CO2 storage conditions 含有不同二氧化碳抗性添加剂的井筒水泥在二氧化碳地质封存条件下的性能表征

0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.geoen.2024.213510

Manguang Gan , Theogene Hakuzweyezu , Liwei Zhang , Yan Wang , Qinglong Qin , Kaiyuan Mei , Xiaowei Cheng

CO₂ geological utilization and storage (CGUS) is an effective method for reducing greenhouse gas (GHG) emissions and mitigating their global warming effects. Wellbore cement is a crucial component of the CGUS system, but it exhibits chemical instability when exposed to CO₂-rich environments, which can lead to potential CO₂ leakage from wellbores. Maintaining the integrity of the wellbore cement is essential for preventing CO₂ leakage, ensuring the long-term containment of CO₂ in subsurface formations, and ensuring the success of CGUS projects. The objective of this study is to evaluate the impact of different CO₂-resisting additives on the corrosion depth, compressive strength, and the pore structure of wellbore cement when exposed to CO₂-saturated brine under geologic CO₂ storage conditions. The mineralogy, microstructure, and morphology of specimens with different additives were analyzed using XRF, XRD, SEM and micro-CT. The results show that the cement containing supercritical CO₂-modified Ca-montmorillonite (CM) was more effective in resisting CO₂ corrosion than biochar (BC), crystalline admixture (CA), and geopolymer (GP). The corrosion inhibition efficiency, when compared to the reference sample (00-RF), followed the descending order of CM (44.04%), GP (26.17%), and BC (6.49%). Adding CA to the cement not only failed to inhibit corrosion but also increased the carbonation depth within the wellbore cement by 35.78%. The analysis of CM indicates that its reinforcement mechanisms stem from micro calcite-induced carbonate growth and montmorillonite swelling, and the prevention of CO₂ infiltration is attributed to the structure of montmorillonite after supercritical CO₂ modification. Regarding compressive strength, all samples with different additives exhibited a decline after CO₂ corrosion. The sample containing supercritical CO₂-modified CM showed the smallest reduction in compressive strength (10.40%) after carbonation while the sample with GP has the highest reduction (54.63%). In summary, compared to the other additives, CO₂-modified montmorillonite has the most promising application prospect.

二氧化碳地质利用和封存（CGUS）是减少温室气体（GHG）排放和减轻其全球变暖效应的有效方法。井筒水泥是 CGUS 系统的重要组成部分，但它在富含二氧化碳的环境中会表现出化学不稳定性，从而可能导致二氧化碳从井筒泄漏。保持井筒水泥的完整性对于防止二氧化碳泄漏、确保二氧化碳在地下地层中的长期封存以及确保 CGUS 项目的成功至关重要。本研究的目的是评估在二氧化碳地质封存条件下，不同的抗二氧化碳添加剂在暴露于二氧化碳饱和盐水时对井筒水泥的腐蚀深度、抗压强度和孔隙结构的影响。使用 XRF、XRD、SEM 和显微 CT 分析了含有不同添加剂的试样的矿物学、微观结构和形态。结果表明，与生物炭（BC）、晶体掺合料（CA）和土工聚合物（GP）相比，含有超临界 CO2 改性钙蒙脱石（CM）的水泥能更有效地抵抗 CO2 腐蚀。与参考样品（00-RF）相比，缓蚀效率从高到低依次为 CM（44.04%）、GP（26.17%）和 BC（6.49%）。在水泥中添加 CA 不仅不能抑制腐蚀，还会使井筒水泥的碳化深度增加 35.78%。对CM的分析表明，其强化机理源于微方解石诱导的碳酸盐增长和蒙脱石膨胀，而防止CO2渗透则归因于超临界CO2改性后蒙脱石的结构。在抗压强度方面，所有含有不同添加剂的样品在受到二氧化碳腐蚀后都出现了下降。含有超临界 CO2 改性 CM 的样品在碳化后的抗压强度下降幅度最小（10.40%），而含有 GP 的样品下降幅度最大（54.63%）。总之，与其他添加剂相比，二氧化碳改性蒙脱石的应用前景最为广阔。

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引用次数: 0

Experimental investigation on enhanced oil recovery of heavy oil via cyclic supercritical water stimulation 通过循环超临界水刺激提高重油采收率的实验研究

0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.geoen.2024.213525

Lei Chen , Zujie Huang , Qiuyang Zhao , Yan Miao , Hui Jin , Yechun Wang , Liejin Guo

With the gradual depletion of conventional oil resources, the exploitation of heavy oil is essential to alleviate the energy crisis, as fossil energy remains predominant in global energy supply. The feasibility of cyclic supercritical water (SCW) stimulation is confirmed by oil field tests, while the enhanced oil recovery (EOR) mechanisms and the dynamic characteristics of displacement are still unclear owing to the scarceness of relevant studies. In this study, an experimental system with a design temperature up to 450 °C and pressure up to 30 MPa was developed to simulate the cyclic SCW stimulation process. A customized two-dimensional sand pack core with equitable temperature measuring arrangement can monitor the dynamic evolution of temperature field. The results of the core experiments indicated that the injection of SCW obviously enhances oil production, with the ultimate oil recovery factor up to 75.91%, which was 18.85% higher than that of steam. The formation and expansion of the SCW gravity override was found to be one of the mechanisms for boosting oil production. At the end, the swept volume coefficient of SCW was enlarged from 5.39% to 10.53%, which was 2.99 times that of steam. The large expansion of the gravity override zone of SCW in the vertical and radial directions changes the heat and mass transfer law, raises the core temperature, and expands the swept volume. Further, the condensation of supercritical water in the soak stage caused pressure difference (up to 11.12 MPa) near the well driving distant heavy oil to flow towards. These findings have the potential to deepen the understanding of the EOR mechanisms of SCW stimulation and provide theoretical guidance for improving oil production in oilfields.

随着常规石油资源的逐渐枯竭，在化石能源仍占全球能源供应主导地位的情况下，重油开采对于缓解能源危机至关重要。油田试验证实了循环超临界水（SCW）刺激的可行性，但由于相关研究较少，其提高石油采收率（EOR）机理和位移的动态特性仍不清楚。本研究开发了一个设计温度高达 450 ℃、压力高达 30 MPa 的实验系统，用于模拟循环 SCW 激励过程。定制的二维砂包岩心具有公平的温度测量布置，可监测温度场的动态演变。岩心实验结果表明，注入 SCW 能明显提高石油产量，最终采油系数高达 75.91%，比蒸汽采油系数高出 18.85%。研究发现，超临界水重力超限的形成和膨胀是提高石油产量的机制之一。最终，超临界水的扫容积系数从 5.39% 扩大到 10.53%，是蒸汽的 2.99 倍。超临界水重力覆盖区在垂直和径向方向上的大幅扩张改变了传热传质规律，提高了核心温度，扩大了扫余体积。此外，超临界水在浸泡阶段的凝结造成了油井附近的压力差（高达 11.12 兆帕），促使远处的重油流向油井。这些发现有望加深人们对超临界水刺激 EOR 机理的理解，并为提高油田的石油产量提供理论指导。

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引用次数: 0

Transformative reconstruction of missing acoustic well logs using multi-head self-attention BiRNNs 利用多头自注意 BiRNN 对缺失的声波测井记录进行变换重建

0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.geoen.2024.213513

Xiangyu Fan , Fan Meng , Juan Deng , Amir Semnani , Pengfei Zhao , Qiangui Zhang

Acoustic well logs are vital for many industrial projects, such as mining, oil and gas, civil engineering, geothermal energy, water resource exploration, mineral exploration, and carbon capture and storage.

However, these important well log data, which reveal acoustic properties of the subsurface properties, due to operational or financial constraints, may not be always available. This hinders well planning, drilling operation risk assessment, reservoir evaluation, and production optimization in these projects.

In recent years, deep learning has gained prominence in well log prediction. Recurrent neural networks (RNNs), especially suited for capturing geological-driven trends in well logs, have emerged as a preferred technique. Multihead attention (MHA) is used to evaluate diverse facets of relationships within the data, enhancing contextual understanding and overcoming challenges.

To the best of our knowledge, this study, for the first time, has examined three RNN variants, (BiRNN, BiLSTM and BiGRU), combined with MHA mechanism for the objective of reconstructing acoustic well logs using the existing well log data (i.e. Neutron, Gamma, Density). To this aim, three different models, MHA-BiRNN, MHA-BiLSTM, and MHA-BiGRU were designed, trained, validated and tested on well logging data taken from Shengli Oilfield. It is noteworthy that, to enhance the significance and reliability of the models, the dataset originated from a discerningly selected subset of 100 wells, purposefully chosen from a pool of 463 (making over 500,000 sequences). This deliberate approach ensures the impartiality of the data, enhancing the trustworthiness and robustness of our models.

The results showed promising performance of MHA-BiGRU, MHA-BiRNN and MHA-BiLSTM in capturing nonlinear relationships and vertical depth sequence information between logging curves and good prediction accuracy in actual testing wells. Among them, MHA-BiGRU outperformed (R2 = 0.807, Pearson = 0.914). The proposed method provides a fast and effective way for filling missing values, which is valuable for geological research and engineering applications.

声学测井对采矿、石油和天然气、土木工程、地热能源、水资源勘探、矿产勘探以及碳捕集与封存等许多工业项目至关重要。然而，由于操作或资金限制，这些揭示地下声学特性的重要测井数据可能并不总是可用。这阻碍了这些项目中的油井规划、钻井作业风险评估、储层评估和生产优化。近年来，深度学习在测井预测中的作用日益突出。递归神经网络（RNN）尤其适合捕捉测井记录中的地质驱动趋势，已成为一种首选技术。据我们所知，本研究首次研究了三种 RNN 变体（BiRNN、BiLSTM 和 BiGRU），并将其与 MHA 机制相结合，目的是利用现有的测井数据（即中子、伽马和密度）重建声学测井。为此，我们设计了三种不同的模型：MHA-BiRNN、MHA-BiLSTM 和 MHA-BiGRU，并对胜利油田的测井数据进行了训练、验证和测试。值得注意的是，为了提高模型的意义和可靠性，数据集来自于从 463 口井（超过 500,000 个序列）中精心挑选的 100 口井。结果表明，MHA-BiGRU、MHA-BiRNN 和 MHA-BiLSTM 在捕捉测井曲线之间的非线性关系和垂直深度序列信息方面表现出色，在实际测试井中具有良好的预测精度。其中，MHA-BiGRU 的性能更优（R2 = 0.807，Pearson = 0.914）。所提出的方法为填补缺失值提供了一种快速有效的方法，对地质研究和工程应用具有重要价值。

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引用次数: 0

Nonlinear interpolated Variational Autoencoder for generalized fluid content estimation 用于广义流体含量估算的非线性插值变异自动编码器

0 ENERGY & FUELS

Geoenergy Science and Engineering

Pub Date : 2024-11-15 DOI: 10.1016/j.geoen.2024.213474

Hasan Asyari Arief , Peter James Thomas , Weichang Li , Christian Brekken , Magnus Hjelstuen , Ivar Eskerud Smith , Steinar Kragset , Aggelos Katsaggelos

Generalizing machine learning models for petroleum applications, especially in scenarios with limited and less varied training data compared to real-world conditions, remains a persistent challenge. This study introduces a novel method combining interpolation mixup with a Variational Autoencoder (VAE) and adaptable interpolation loss for downstream regression tasks. By implementing this approach, we generate high-quality interpolated samples, yielding accurate estimations. Experimental validation on a real-world industrial dataset focused on fluid content measurement demonstrates the superior performance of our method compared to other interpolation and regularization techniques. Our approach achieves over a 15% improvement on generalized out-of-distribution datasets, offering crucial insights for fluid content estimation and practical implications for industrial applications.

将机器学习模型泛化到石油应用中，尤其是在训练数据有限且与真实世界条件相比变化较少的情况下，仍然是一个长期存在的挑战。本研究介绍了一种新方法，它将插值混合与变异自动编码器（VAE）和可调整的插值损失相结合，用于下游回归任务。通过采用这种方法，我们生成了高质量的插值样本，从而获得了准确的估计结果。在以流体含量测量为重点的真实世界工业数据集上进行的实验验证表明，与其他插值和正则化技术相比，我们的方法性能优越。我们的方法在广义分布外数据集上取得了超过 15% 的改进，为流体含量估算提供了重要见解，并对工业应用产生了实际影响。

引用次数: 0