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Environmentally Friendly Production of Energy from Natural Gas Hydrates

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A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Energy Systems".

Deadline for manuscript submissions: 31 December 2025 | Viewed by 9360

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Special Issue Editors

Dr. Qingchao Li

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Guest Editor

School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo, 454000, China.
Interests: Natural gas hydrate; CCUS; Wellbore stability; Sand Production

Dr. Qiang Li

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Guest Editor

College of Engineering, China University of Petroleum-Beijing at Karamay, Karamay, 834000, China.
Interests: CCU; Natural gas hydrate; Shale gas; Hydraulic Fracturing

Special Issue Information

Dear Colleagues,

Natural gas is considered a clean energy source that enables human society to transition from a fossil fuel-dominated phase to a sustainable and renewable energy-dominated phase. Fortunately, natural gas hydrates could become an important source of natural gas in the near future. It was estimated that the global reserves of natural gas hydrates are as high as 3 × 10¹⁵ m³, which is about double the reserves of conventional fossil fuels (such as oil, gas, and coal). In the stable structure of gas hydrate, natural gas is firmly fixed in the center of the cage structure that is composed of water molecules. Once its stable state is disturbed, natural gas escapes from the cage structure, allowing it to be extracted and utilized. At present, the commonly used development strategies mainly include depressurization, thermal stimulation, inhibitor injection, and CO₂ replacement. Unfortunately, there will be many environmental challenges during its long-term development process using these strategies. For example, inhibitors injected into hydrate-bearing sediments can contaminate pore fluids and cause damage to the reservoir. Therefore, exploring strategies for producing energy from natural gas hydrates in an environmentally friendly and efficient manner has become particularly important.

This Special Issue on “Environmentally Friendly Production of Energy from Natural Gas Hydrates” seeks high-quality research focusing on environmentally friendly production strategies for natural gas hydrates. Topics include, but are not limited to, the following:

(1) Impact of hydrate development on the environment and ecology, including analysis of engineering geological issues, methane leakage, reservoir damage, and contamination by chemical reagents.
(2) Development of environmentally friendly chemicals for hydrate development, such as drilling fluid additives, fracturing fluid additives, and various inhibitors.
(3) Application of industrial waste (such as power plant flue gas and waste heat) or low-quality energy (such as geothermal energy) in the efficient development of hydrates.
(4) Economic and technical evaluation of various environmentally friendly production strategies for natural gas hydrates.

Dr. Qingchao Li
Dr. Qiang Li
Guest Editors

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Keywords

natural gas hydrate
production strategy
additives
inhibitors
wellbore stability
sand production
reservoir damage
geothermal
economic and technical evaluation

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Published Papers (12 papers)

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Research

21 pages, 5591 KiB

Open AccessArticle

Adaptability Evaluation of Hybrid Riser-Based Riserless Mud Recovery System for Deepwater Natural Gas Hydrate Exploration and Development

by Jing Zeng, Wenwei Xie, Yanjiang Yu, Kewei Zhang, Haowen Chen, Bin Li, Fangfei Huang, Kaixiang Shen, Qiuping Lu and Haoyu Yu

Processes 2025, 13(6), 1749; https://doi.org/10.3390/pr13061749 - 2 Jun 2025

Viewed by 322

Abstract

Deepwater natural gas hydrate (NGH) exploration faces environmental and economic challenges due to the conventional seabed discharge of drilling mud. To address this, we developed an improved riserless mud recovery (RMR) system using hybrid risers to create a stable, decoupled circulation pathway. This innovative design fulfils three key operational needs: (1) closed-loop drilling fluid circulation with dual-gradient control, (2) completion fluid and test production returns, and (3) mechanical decoupling between the floating platform and subsea riser string. Numerical analysis shows that the system maintains operational stability under wave loading while effectively isolating seabed equipment from platform motion. Simulation results indicate that optimal performance requires a top tension ratio exceeding 1.5 and a submersion depth of 150–250 m, achieving a 70–80% reduction in drilling fluid consumption with full recovery capabilities. The hybrid riser-based RMR system provides a practical solution for sustainable NGH development, offering superior water depth adaptability for both drilling and completion operations in deepwater environments. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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17 pages, 9105 KiB

Open AccessArticle

The Law of Acid Pressure Fracture Propagation in Maokou Formation Carbonate Reservoir in Central Sichuan

by Yu Fan, Hailong Jiang, Zhouyang Wang, Jinsui Li, Xing Yang, Zefei Lv, Xiangfei Zhang and Xueyuan Han

Processes 2025, 13(6), 1634; https://doi.org/10.3390/pr13061634 - 22 May 2025

Viewed by 405

Abstract

The Dolomite reservoir of the Maokou Formation is rich in gas resources in the central Sichuan Basin. Acid fracturing is an important technical means to improve reservoir permeability and productivity. The interaction mode of the dolomite and limestone acid system will affect the effect of reservoir reconstruction. In order to clarify the influence of complex structure on fracture morphology, we explore the fracturing effect of different acid systems. Physical simulation experiments of true triaxial acid fracturing were carried out with two acid systems and downhole full-diameter cores. The experimental results show: (1) After the carbonate rock is subjected to acid fracturing using a “self-generated acid + gel acid” system, the fracture pressure drops significantly by up to 60%. The morphology of the acid-eroded fractures becomes more complex, with an increase in geometric complexity of about 28% compared to a single acid solution system. It is prone to form three-dimensional “spoon” shaped fractures, and the surface of the acid-eroded fractures shows light yellow acid erosion marks. Analysis of the acid erosion marks indicates that the erosion depth on the fracture surface reaches 0.8–1.2 mm, which is deeper than the 0.2 mm erosion depth achieved with a single system. (2) Acid solution is difficult to penetrate randomly distributed calcite veins with a low porosity and permeability structure. When the fracture meets the calcite vein, the penetration rate of acid solution drops sharply to 15–20% of the initial value, resulting in a reduction of about 62% of the acid erosion area in the limestone section behind. And the acid erosion traces in the limestone behind the calcite vein are significantly reduced. The acid erosion cracks are easy to open on the weak surface between dolomite and limestone, causing the fracture to turn. (3) The results of field engineering and experiment are consistent, and injecting authigenic acid first in the process of reservoir reconstruction is helpful to remove pollution. The recovery rate of near-well permeability is more than 85% with pre-generated acid. Reinjection of gelled acid can effectively communicate the natural weak surface and increase the complexity of cracks. The average daily oil production of the completed well was increased from 7.8 m³ to 22.5 m³, and the increase factor reached 2.88. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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22 pages, 4552 KiB

Open AccessArticle

Wellhead Stability During Development Process of Hydrate Reservoir in the Northern South China Sea: Sensitivity Analysis

by Qingchao Li, Qiang Li, Jingjuan Wu, Kaige He, Yifan Xia, Junyi Liu, Fuling Wang and Yuanfang Cheng

Processes 2025, 13(6), 1630; https://doi.org/10.3390/pr13061630 - 22 May 2025

Cited by 6 | Viewed by 396

Abstract

Natural gas hydrates are a promising alternative energy source for oil and gas in the future. However, geomechanical issues, such as wellhead instability, may arise, affecting the safe and efficient development of hydrates. In the present work, a sensitivity analysis was performed on sediment subsidence and wellhead instability during the development of marine hydrates using a multi-field coupled model. This is accomplished by adjusting the corresponding parameters based on the basic data of the default case. Meanwhile, the corresponding influencing mechanisms were explored. Finally, design recommendations for operation parameters were proposed based on the research findings regarding wellhead stability. It was found that the wellhead undergoes rapid sinking during a certain period in the early stage of hydrate development, followed by a slower, continued sinking. The sensitivity analysis found that when the depressurization amplitude is small, the wellhead sinking is also minimal. To maintain wellhead stability during the development process, it is recommended that neither the depressurization amplitude or drawdown pressure exceed 3.0 MPa. Although a high heating temperature can increase gas production to some extent, the accompanying excessive hydrate dissociation may compromise the stability of both the formation and wellhead. To balance gas production and wellhead stability, it is recommended that the heating amplitude does not exceed 50 °C. In addition, the permeability influences the distribution of pore pressure, which in turn affects sediment subsidence and wellbore stability. Wellhead stability deteriorates as permeability increases. Therefore, it is crucial to accurately determine the reservoir characteristics (such as permeability) before developing hydrates to avoid wellhead instability. Finally, the investigation results reveal that using different versions of the investigation model can impact the accuracy of the results, and neglecting certain physical fields may lead to an underestimation of the wellhead sinking. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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26 pages, 11288 KiB

Open AccessArticle

Application of Composite Drainage and Gas Production Synergy Technology in Deep Coalbed Methane Wells: A Case Study of the Jishen 15A Platform

by Longfei Sun, Donghai Li, Wei Qi, Li Hao, Anda Tang, Lin Yang, Kang Zhang and Yun Zhang

Processes 2025, 13(5), 1457; https://doi.org/10.3390/pr13051457 - 9 May 2025

Viewed by 373

Abstract

The development of deep coalbed methane (CBM) wells faces challenges such as significant reservoir depth, low permeability, and severe liquid loading in the wellbore. Traditional drainage and gas recovery techniques struggle to meet the dynamic production demands. This study, using the deep CBM wells at the Jishen 15A platform as an example, proposes a “cyclic gas lift–wellhead compression-vent gas recovery” composite synergy technology. By selecting a critical liquid-carrying model, innovating equipment design, and dynamically regulating pressure, this approach enables efficient production from low-pressure, low-permeability gas wells. This research conducts a comparative analysis of different critical liquid-carrying velocity models and selects the Belfroid model, modified for well inclination angle effects, as the primary model to guide the matching of tubing production and annular gas injection parameters. A mobile vent gas rapid recovery unit was developed, utilizing a three-stage/two stage pressurization dual-process switching technology to achieve sealed vent gas recovery while optimizing pipeline frictional losses. By combining cyclic gas lift with wellhead compression, a dynamic wellbore pressure equilibrium system was established. Field tests show that after 140 days of implementation, the platform’s daily gas production increased to 11.32 × 10⁴ m³, representing a 35.8% rise. The average bottom-hole flow pressure decreased by 38%, liquid accumulation was reduced by 72%, and cumulative gas production increased by 370 × 10⁴ m³. This technology effectively addresses gas–liquid imbalance and liquid loading issues in the middle and late stages of deep CBM well production, providing a technical solution for the efficient development of low-permeability CBM reservoirs. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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20 pages, 6474 KiB

Open AccessArticle

Study on Prediction of Wellbore Collapse Pressure of the Coal Seam Considering a Weak Structure Plane

by Dongsheng Li, Kaiwei Chen, Jian Li, Liang Xue and Zhongying Han

Processes 2025, 13(3), 803; https://doi.org/10.3390/pr13030803 - 10 Mar 2025

Viewed by 603

Abstract

To investigate the influence of weakly structured formations on wellbore stability in deep coal seams within the Lufeng Block, this study establishes an innovative predictive model for coal seam wellbore collapse pressure. The model integrates mechanical parameter variations along weak structural planes with the Mohr–Coulomb criterion, leveraging experimental correlations between mechanical properties and bedding angle. Key findings reveal that the coal sample demonstrates enhanced compressive strength and elastic modulus under elevated confining pressures. A distinctive asymmetric “V” pattern emerges in mechanical parameter evolution: compressive strength, elastic modulus, cohesion, and internal friction angle initially decrease before recovering with increasing bedding angle, reaching minimum values at a 60° bedding angle. Comparative analysis demonstrates that the proposed model predicts a higher collapse pressure equivalent density than conventional Mohr–Coulomb approaches, particularly when accounting for mechanical parameter alterations along weak structural planes. Field validation through coal seam data from the operational well confirms the model’s effectiveness for stability analysis in weakly structured coal formations within the Lufeng Block. These findings provide critical theoretical support for wellbore stability management in deep coal seam engineering applications. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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21 pages, 12715 KiB

Open AccessArticle

Effect of Twisted Tapes on Swirling Flow Dynamics in Gas–Solid Two-Phase Flows for Natural Gas Hydrate Transportation

by Yongchao Rao, Zijia Gong, Shuli Wang, Chenglong Zhang, Yunxiao Wang and Chuang Wen

Processes 2025, 13(3), 781; https://doi.org/10.3390/pr13030781 - 7 Mar 2025

Viewed by 696

Abstract

The discrete phase model (DPM) and the RNG k-ε turbulence model were employed to simulate the swirl flow behavior of hydrate transport in pipelines equipped with twisted tapes. The study analyzed the effects of various twisted tape parameters on the velocity field, turbulent dissipation, turbulent kinetic energy, and pressure distribution of hydrate particles. The results indicate that increasing the placement angle of the twisted tape enhances the tangential velocity near the pipe axis while reducing the axial velocity. Similarly, higher twisted tape configurations result in a further decrease in axial velocity. An increase in the number of twisted tapes leads to reductions in both tangential and axial velocities, and maximum speed increased by 18.2%. Larger placement angles of twisted tapes also intensify turbulence dissipation, with a more pronounced decay in turbulence intensity observed from the pipe wall to the axis. At section 8D, the turbulent kinetic energy increases by 60% with the increase in the height of the twisted tapes. Furthermore, as the number of twisted tapes increases, the disparity in turbulence strength between regions near the twisted tape and the pipe axis diminishes. The inner pipe pressure distribution is 360°/n rotation symmetrical distribution, and the twist tape is more, and the high pressure area is greater on the pipe section. The minimum pressure area is gradually close from the lee plane of the diversion strip to the position of the pipe axis. At section 65D, the pressure drop increases gradually with the increase in the orientation angle, and it increases by 36.8%. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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19 pages, 2769 KiB

Open AccessArticle

Two-Phase Swirling Flow and Gas Hydrate Particle Deposition Behavior in Bending Pipelines

by Yongchao Rao, Long Zheng, Shuli Wang, Wenjing Wu, Zijia Gong, Shidong Zhou and Chuang Wen

Processes 2025, 13(3), 725; https://doi.org/10.3390/pr13030725 - 3 Mar 2025

Viewed by 742

Abstract

The present study employs numerical simulation to analyze the behavior of gas hydrate particles in bending pipelines, focusing on the influence of swirl flow on particle deposition under varying bending angles, pipe-to-diameter ratios, Reynolds numbers, and twist rates. Results indicate that larger bending angles, smaller twist rates, and higher Reynolds numbers produce stronger swirl flows at pipe entry and sustain higher swirl numbers along the pipeline. Conversely, larger pipe-to-diameter ratios result in greater swirl number variations, slower attenuation, and weaker outflow. Moreover, the phenomenon of hydrate particle deposition is more serious in the straight pipe section. Particle retention at the pipe outlet is 1.5 times higher than in the bending section. The bent pipe is more conducive to the flow of particles. For instance, with a bend rate increasing from 1 to 4, the swirl number decreases by 57.49%. Additionally, the deposition rate of particles is reduced at higher Reynolds numbers, with rates falling below 1% at a Reynolds number of 20,000. These findings highlight the need to optimize swirl flow parameters to reduce hydrate deposition, preventing blockages and improving pipeline safety in industrial applications. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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20 pages, 10429 KiB

Open AccessArticle

A Numerical Simulation Investigation on the Distribution Characteristics of Coal Seam In Situ Stress Under the Influence of Normal Fault

by Zhihua Rao, Qingjie Du, Chunsheng Xiang, Zhongying Han and Yanbo Liang

Processes 2025, 13(2), 538; https://doi.org/10.3390/pr13020538 - 14 Feb 2025

Viewed by 565

Abstract

This study focuses on the complex stress distribution in coal seams influenced by normal fault using the fault development zone of the LF-M1 oilfield in southern China as a case study. Based on 3D seismic and drilling data, a key research area was delineated, and strata were reclassified considering rock parameter similarity. An FLAC3D model encompassing hanging wall, normal fault, and footwall strata was developed to systematically analyze geostress near the fault under various conditions. The results indicate that the normal fault induces non-uniform and discontinuous stress patterns in the coal seam’s transverse plane. Stress weakening occurs near the fault, with a pronounced concentration on its flanks, approaching in situ stress levels in the far field. Coal’s Poisson’s ratio, elastic modulus, and fault dip negatively correlate with horizontal in situ stress, whereas other parameters show positive correlations. The maximum horizontal stress is more sensitive to parameter variations than the minimum. Stress weakening is most influenced by coal’s Poisson’s ratio, followed by coal’s elastic modulus, fault elastic modulus, fault Poisson’s ratio, fault dip, and fault thickness and the coal seam thickness. Notably, a 20% decrease in coal’s Poisson’s ratio leads to a 23.32% stress reduction at measuring point 1. Conversely, the coal seam thickness has a minimal impact on stress across the fault. When the coal seam thickness increases by 20%, the maximum horizontal stress at measuring point 2 only decreases by 0.06%. In summary, fault geometry, rock mechanics parameters, and external loads collectively complicate stress distributions near faults, posing risks of drilling accidents such as wellbore instability, leakage, and reservoir damage, necessitating careful consideration. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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16 pages, 6464 KiB

Open AccessArticle

Prospects on Mixed Tutton Salt (K_0.86Na_0.14)₂Ni(SO₄)₂(H₂O)₆ as a Thermochemical Heat Storage Material

by Jacivan V. Marques, João G. de Oliveira Neto, Otávio C. da Silva Neto, Adenilson O. dos Santos and Rossano Lang

Processes 2025, 13(1), 1; https://doi.org/10.3390/pr13010001 - 24 Dec 2024

Cited by 5 | Viewed by 813

Abstract

In this paper, a novel mixed Tutton salt (K_0.86Na_0.14)₂Ni(SO₄)₂(H₂O)₆ was successfully synthesized as a single crystal and evaluated as a thermochemical heat storage material. Its thermal and thermochemical properties were correlated with the structure, which was determined by powder X-ray diffraction using the Le Bail and Rietveld methods. The elemental ratio between the K⁺ and Na⁺ monovalent cations was established by energy-dispersive X-ray spectroscopy. Similar compounds such as Na₂Ni(SO₄)₂(H₂O)₄ and K₂Ni(SO₄)₂(H₂O)₆ were also synthesized and used for structural comparisons. The (K_0.86Na_0.14)₂Ni(SO₄)₂(H₂O)₆ salt crystallizes in monoclinic symmetry with the P2₁/c-space group, typical of hexahydrate crystals from the Tutton salt family. The lattice parameters closely resemble those of K₂Ni(SO₄)₂(H₂O)₆. A comprehensive analysis of the intermolecular contacts, based on Hirshfeld surfaces and 2D fingerprint mappings, revealed that the primary interactions are hydrogen bonds (H···O/O···H) and ion-dipole interactions (K/Na···O/O···Na/K). The unit cell exhibits minimal void space, accounting for only 0.2%, indicative of strong atomic packing. The intermolecular molecular and atomic packing are important factors influencing crystal lattice stabilization and thermal energy supplied to release crystallographic H₂O. The thermal stability of mixed Tutton salt ranges from 300 K to 365 K. Under the dehydration of its six H₂O molecules, the dehydration reaction enthalpy reaches 349.8 kJ/mol, yielding a thermochemical energy storage density of 1.79 GJ/m³. With an H₂O desorption temperature ≤393 K and a high energy storage density ≥1.3 GJ/m³ (criteria established for applications at the domestic level), the (K_0.86Na_0.14)₂Ni(SO₄)₂(H₂O)₆ shows potential as a thermochemical material for small-sized heat batteries. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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18 pages, 8443 KiB

Open AccessArticle

Effects of Modified Cross-Linkers on the Rheology of Water-Based Fracturing Fluids and Reservoir Water Environment

by Hua Song and Junyi Liu

Processes 2024, 12(12), 2896; https://doi.org/10.3390/pr12122896 - 18 Dec 2024

Cited by 1 | Viewed by 830

Abstract

Improving the chemical structure of the cross-linker is a potential method for reducing reservoir pollution and enhancing the fracturing efficiency of shale reservoirs. In this investigation, a three-dimensional (3-D) spherical cross-linker comprising branched chains was synthesized, and the 3-D structure of the cross-linker was analyzed through scanning electron microscopy (SEM). Furthermore, we constructed a multifunctional coupled collaborative evaluation device that can be used to evaluate numerous properties associated with water-based fracturing fluids, including fluid viscosity, adsorption capacity, and water pollution. Meanwhile, the influence of varying reservoir conditions and cross-linker content on the fluid viscosity of water-based fracturing fluids and the potential for reservoir contamination has been evaluated and elucidated. The results indicated that the synthesized cross-linker exhibited a superior environmental protection of the shale reservoir and an enhanced capacity for thickening fracturing fluids in comparison to commercial cross-linkers. Moreover, cross-linker content, reservoir temperature, reservoir pressure, and fracture width can affect fluid viscosity and reservoir residual in different trends. The addition of 0.3% nano-cross-linker (Synthetic products) to a water-based fracturing fluid resulted in an apparent viscosity of 160 mPa·s at 200 °C, and the adsorption capacity and water content of the shale reservoir were only 0.22 µg/m³ and 0.05 µg/L, respectively. Additionally, an elevation in reservoir temperature resulted in a reduction in the adsorption capacity. However, the cross-linker content in groundwater underwent a notable increase, and the cross-linker residue in water increased by 0.009 µg/L. The impact of reservoir pressure on fluid viscosity and groundwater pollution potential exhibited an inverse correlation compared to that of reservoir temperature, and the above two parameters changed by +18 mPa·s and −0.012 µg/L, respectively. This investigation provides basic data support for the efficient fracturing and reservoir protection of shale reservoirs. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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28 pages, 7321 KiB

Open AccessFeature PaperArticle

Experimental Study on the Stress Sensitivity Characteristics of Wave Velocities and Anisotropy in Coal-Bearing Reservoir Rocks

by Zehua Zhang, Xiaokai Xu, Kuo Jian, Liangwei Xu, Jian Li, Dongyuan Zhao, Zhengzheng Xue and Yue Xin

Processes 2024, 12(12), 2819; https://doi.org/10.3390/pr12122819 - 9 Dec 2024

Viewed by 837

Abstract

As the effective stress in coal-bearing reservoirs changes, the elastic wave velocities, stress sensitivity, and anisotropic characteristics of coal rocks exhibit certain variations. Therefore, this study selected samples from the same area (sandstone, mudstone, and anthracite) and conducted experiments on their transverse wave velocities (V_s) and longitudinal wave velocities (V_p) and wave velocity ratios in three directions (one perpendicular and two parallel to the layering), using the RTR-2000 testing system under loading pressure conditions. The results indicate that the longitudinal and transverse wave velocities of the coal rock samples show a phase-wise increase with rising pressure. The wave velocities and wave velocity ratios of sandstone, mudstone, and anthracite demonstrate certain anisotropic characteristics, with an overall trend of decreasing anisotropy strength that stabilizes over time. The anisotropic characteristics of the longitudinal wave velocities in sandstone and mudstone are stronger than those of the transverse wave velocities, whereas in anthracite, the anisotropic characteristics of the transverse wave velocities are stronger than those of the longitudinal wave velocities. Thus, it can be concluded that V_p is a sensitive parameter for detecting the anisotropic characteristics of sandstone and mudstone, while V_s serves as a sensitive parameter for detecting the anisotropic characteristics of anthracite. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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17 pages, 3088 KiB

Open AccessArticle

The Carrying Behavior of Water-Based Fracturing Fluid in Shale Reservoir Fractures and Molecular Dynamics of Sand-Carrying Mechanism

by Qiang Li, Qingchao Li, Fuling Wang, Jingjuan Wu and Yanling Wang

Processes 2024, 12(9), 2051; https://doi.org/10.3390/pr12092051 - 23 Sep 2024

Cited by 83 | Viewed by 1793

Abstract

Water-based fracturing fluid has recently garnered increasing attention as an alternative oilfield working fluid for propagating reservoir fractures and transporting sand. However, the low temperature resistance and stability of water-based fracturing fluid is a significant limitation, restricting the fracture propagation and gravel transport. To effectively ameliorate the temperature resistance and sand-carrying capacity, a modified cross-linker with properties adaptable to varying reservoir conditions and functional groups was synthesized and chemically characterized. Meanwhile, a multifunctional collaborative progressive evaluation device was developed to investigate the rheology and sand-carrying capacity of fracturing fluid. Utilizing molecular dynamics simulations, the thickening mechanism of the modified cross-linker and the sand-carrying mechanism of the fracturing fluid were elucidated. Results indicate that the designed cross-linker provided a high viscosity stability of 130 mPa·s and an excellent sand-carrying capacity of 15 cm² at 0.3 wt% cross-linker content. Additionally, increasing reservoir pressure exhibited enhanced thickening and sand-carrying capacities. However, a significant inverse relationship was observed between reservoir temperature and sand-carrying capacity, attributed to changes in the drag coefficient and thickener adsorption. These results verified the effectiveness of the cross-linker in enhancing fluid viscosity and sand-carrying capacity as a modified cross-linker for water-based fracturing fluid. Full article

(This article belongs to the Special Issue Environmentally Friendly Production of Energy from Natural Gas Hydrates)

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