Zhengzheng Cao¹, Shuaiyang Zhang¹, Cunhan Huang^2,*, Feng Du^3,4, Zhenhua Li^3,4, Shuren Wang¹, Wenqiang Wang^3,4, Minglei Zhai^3,4

FDMP-Fluid Dynamics & Materials Processing, Vol.21, No.5, pp. 1007-1028, 2025, DOI:10.32604/fdmp.2025.062738 - 30 May 2025

Abstract Karst collapse columns typically appear unpredictably and without a uniform spatial arrangement, posing challenges for mining operations and water inrush risk assessment. As major structural pathways for mine water inrush, they are responsible for some of the most frequent and severe water-related disasters in coal mining. Understanding the mechanisms of water inrush in these collapse columns is therefore essential for effective disaster prevention and control, making it a key research priority. Additionally, investigating the developmental characteristics of collapse columns is crucial for analyzing seepage instability mechanisms. In such a context, this paper provides a comprehensive… More > Graphic Abstract

Yongfu Liu¹, Haitao Zhao¹, Xingliang Deng¹, Baozhu Guan¹, Jing Li^2,*, Chengqiang Yang², Guipeng Huang²

Energy Engineering, Vol.122, No.5, pp. 1735-1754, 2025, DOI:10.32604/ee.2025.063706 - 25 April 2025

Abstract The seepage characteristics of shale reservoirs are influenced not only by multi-field coupling effects such as stress field, temperature field, and seepage field but also exhibit evident creep characteristics during oil and gas exploitation. The complex fluid flow in such reservoirs is analyzed using a combination of theoretical modeling and numerical simulation. This study develops a comprehensive mathematical model that integrates the impact of creep on the seepage process, with consideration of factors including stress, strain, and time-dependent deformation. The model is validated through a series of numerical experiments, which demonstrate the significant influence of… More >

Xinli Zhao^1,*, Qianhua Xiao², Xuewei Liu³, Yu Shi⁴, Xiangji Dou¹, Guoqiang Xing¹

FDMP-Fluid Dynamics & Materials Processing, Vol.21, No.2, pp. 427-444, 2025, DOI:10.32604/fdmp.2024.052646 - 06 March 2025

Abstract Tight oil reservoirs face significant challenges, including rapid production decline, low recovery rates, and a lack of effective energy replenishment methods. In this study, a novel development model is proposed, based on inter-fracture injection following volumetric fracturing and relying on a high-temperature and high-pressure large-scale physical simulation system. Additionally, the CMG (Computer Modelling Group Ltd., Calgary City, Canada) software is also used to elucidate the impact of various single factors on the production of horizontal wells while filtering out the interference of others. The effects of fracture spacing, fracture half-length, and the injection-production ratio are… More >

Haijun Yang^1,2,*, Zhenzhong Cai^1,2, Hui Zhang^1,2, Chong Sun^1,2, Jing Li^3,*, Xiaoyu Meng³, Chen Liu⁴, Chengqiang Yang³

Energy Engineering, Vol.122, No.2, pp. 537-560, 2025, DOI:10.32604/ee.2024.058747 - 31 January 2025

Abstract Deep tight reservoirs exhibit complex stress and seepage fields due to varying pore structures, thus the seepage characteristics are significant for enhancing oil production. This study conducted triaxial compression and permeability tests to investigate the mechanical and seepage properties of tight sandstone. A digital core of tight sandstone was built using Computed Tomography (CT) scanning, which was divided into matrix and pore phases by a pore equivalent diameter threshold. A fluid-solid coupling model was established to investigate the seepage characteristics at micro-scale. The results showed that increasing the confining pressure decreased porosity, permeability, and flow More >

Qiang Liu¹, Rujun Wang¹, Yintao Zhang¹, Chong Sun¹, Meichun Yang¹, Yuliang Su^2,*, Wendong Wang², Ying Shi², Zheng Chen²

Energy Engineering, Vol.121, No.10, pp. 2797-2823, 2024, DOI:10.32604/ee.2024.052007 - 11 September 2024

Abstract Deep condensate gas reservoirs exhibit highly complex and variable phase behaviors, making it crucial to understand the relationship between fluid phase states and flow patterns. This study conducts a comprehensive analysis of the actual production process of the deep condensate gas well A1 in a certain oilfield in China. Combining phase behavior analysis and CMG software simulations, the study systematically investigates phase transitions, viscosity, and density changes in the gas and liquid phases under different pressure conditions, with a reservoir temperature of 165°C. The research covers three crucial depletion stages of the reservoir: single-phase flow,… More >

Lijun Mu, Xiaojia Xue, Jie Bai^*, Xiaoyan Li, Xueliang Han

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.6, pp. 1365-1379, 2024, DOI:10.32604/fdmp.2024.049013 - 27 June 2024

Abstract Following large-scale volume fracturing in shale oil reservoirs, well shut-in measures are generally employed. Laboratory tests and field trials have underscored the efficacy of fracturing fluid imbibition during the shut-in phase in augmenting shale oil productivity. Unlike conventional reservoirs, shale oil reservoirs exhibit characteristics such as low porosity, low permeability, and rich content of organic matter and clay minerals. Notably, the osmotic pressure effects occurring between high-salinity formation water and low-salinity fracturing fluids are significant. The current understanding of the mobilization patterns of crude oil in micro-pores during the imbibition process remains nebulous, and the… More >

Huiyan Zhao¹, Xuezhong Chen¹, Zhijian Hu^2,*, Man Chen¹, Bo Xiong³, Jianying Yang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.6, pp. 1313-1330, 2024, DOI:10.32604/fdmp.2024.048840 - 27 June 2024

Abstract Using the typical characteristics of multi-layered marine and continental transitional gas reservoirs as a basis, a model is developed to predict the related well production rate. This model relies on the fractal theory of tortuous capillary bundles and can take into account multiple gas flow mechanisms at the micrometer and nanometer scales, as well as the flow characteristics in different types of thin layers (tight sandstone gas, shale gas, and coalbed gas). Moreover, a source-sink function concept and a pressure drop superposition principle are utilized to introduce a coupled flow model in the reservoir. A… More > Graphic Abstract

Xinyu Zhao^1,2,*, Mofeng Li², Kai Yan², Li Yin³

Energy Engineering, Vol.120, No.12, pp. 2933-2949, 2023, DOI:10.32604/ee.2023.041580 - 29 November 2023

Abstract This study presents an avant-garde approach for predicting and optimizing production in tight reservoirs, employing a dual-medium unsteady seepage model specifically fashioned for volumetrically fractured horizontal wells. Traditional models often fail to fully capture the complex dynamics associated with these unconventional reservoirs. In a significant departure from these models, our approach incorporates an initiation pressure gradient and a discrete fracture seepage network, providing a more realistic representation of the seepage process. The model also integrates an enhanced fluid-solid interaction, which allows for a more comprehensive understanding of the fluid-structure interactions in the reservoir. This is… More >

Xin Huang^1,*, Yunpeng Jiang¹, Daowu Huang¹, Xianke He¹, Xianguo Zhang², Ping Guo³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.6, pp. 1679-1691, 2023, DOI:10.32604/fdmp.2023.025312 - 30 January 2023

Abstract

The seepage mechanism plays a crucial role in low-permeability gas reservoirs. Compared with conventional gas reservoirs, low-permeability sandstone gas reservoirs are characterized by low porosity, low permeability, strong heterogeneity, and high water saturation. Moreover, their percolation mechanisms are more complex. The present work describes a series of experiments conducted considering low-permeability sandstone cores under pressure-depletion conditions (from the Xihu Depression in the East China Sea Basin). It is shown that the threshold pressure gradient of a low-permeability gas reservoir in thick layers is positively correlated with water saturation and negatively correlated with permeability and porosity. The

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Shaowei Wang^1,2, Cong Xu¹, Hao Gu^3,*, Pinghua Zhu¹, Hui Liu¹, Bo Xu⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.131, No.1, pp. 97-117, 2022, DOI:10.32604/cmes.2022.018721 - 24 January 2022

Abstract Many concrete dams seriously suffer from long-term seepage dissolution, and the induced mechanical property deterioration of concrete may significantly affect the structural performance, especially the seismic safety. An approach is presented in this paper to quantify the influence of seepage dissolution on seismic performance of concrete dams. To connect laboratory test with numerical simulation, dissolution tests are conducted for concrete specimens and using the cumulative relative leached calcium as an aging index, a deterioration model is established to predict the mechanical property of leached concrete in the first step. A coupled seepage-calcium dissolution-migration model containing… More >