New Advances in Low-Energy Processes for Geo-Energy Development

Abstract

The development of geo-energy resources, including oil, gas, and geothermal reservoirs, is being transformed through the creation of low-energy processes and innovative technologies. This Special Issue compiles cutting-edge research aimed at enhancing efficiency, sustainability, and recovery during geo-energy extraction. The published studies explore a diverse range of methodologies, such as the nanofluidic analysis of shale oil phase transitions, deep electrical resistivity tomography for geothermal exploration, and hybrid AI-driven production prediction models. Their key themes include hydraulic fracturing optimization, CO₂ injection dynamics, geothermal reservoir simulation, and competitive gas–water adsorption in ultra-deep reservoirs, and these studies combine advanced numerical modeling, experimental techniques, and field applications to address challenges in unconventional reservoirs, geothermal energy exploitation, and enhanced oil recovery. By bridging theoretical insights with practical engineering solutions, this Special Issue provides a comprehensive foundation for future innovations in low-energy geo-energy development.

1. Introduction

Geo-energy resources, which include conventional fossil fuels (e.g., oil and natural gas) and unconventional resources (e.g., geothermal, shale gas, and tight oil), remain indispensable to global energy systems [1,2,3]. These resources are broadly classified as either extractive (hydrocarbons) and renewable (geothermal) [4,5,6], with each playing a critical role in meeting energy demands and balancing environmental sustainability [7,8]. With industrialization and economic recovery driving energy consumption, optimizing the extraction and utilization of these resources through low-energy technologies has become a pivotal focus of current research [9,10,11].

In conventional hydrocarbon development, advancements in drilling, completion, and enhanced oil recovery (EOR) technologies have significantly improved the efficiency of these processes and reduced their energy intensity [12,13,14]. Innovations such as intelligent well systems, high-performance fracturing fluids, and CO₂ injection techniques are reshaping the stimulation and production of reservoirs [15,16]. For instance, polymer flooding and steam-assisted methods are now being adapted to unconventional reservoirs in order to address challenges like low permeability and reservoir heterogeneity [17,18]. Meanwhile, numerical modeling [19,20,21] and big data analytics [22,23,24] are enabling precise reservoir management, minimizing the energy wasted during extraction.

The exploitation of unconventional geo-energy resources, such as geothermal and shale gas, demands even greater innovation [25,26]. Geothermal systems, vital for achieving carbon neutrality, require better heat extraction methods, including better approaches to reservoir fracturing and advanced well designs [8]. Similarly, shale gas and tight oil reservoirs benefit from low-energy hydraulic fracturing, gas–water flow optimization, and the in situ upgrading of their technology [27,28]. Emerging approaches like electromagnetic heating and solar–thermal integration further underscore the shift toward sustainable extraction [29,30,31].

This collection, which is in conversation with the Special Issue of Energies, places an emphasis on fundamental innovations and has compiled 10 new publications on the original application of new ideas and on methodologies that will lead to new advances in low-energy processes for geo-energy development.

2. Review of the Research Presented in This Special Issue

The papers featured in this Special Issue showcase state-of-the-art advancements in low-energy technologies used for geo-energy development. These innovations span three critical areas: unconventional hydrocarbon recovery, geothermal resource exploitation, and intelligent simulation techniques that enhance oil and gas production while minimizing energy consumption.

2.1. Unconventional Hydrocarbon Development Using Low-Energy Technologies

Unconventional reservoirs, such as shale reservoirs and tight formations, require innovative approaches to minimize energy consumption while maximizing recovery. Several studies in this Special Issue address critical challenges in hydraulic fracturing, phase behavior, and gas–water interactions. To study the behavior of fluids in shale oil reservoirs at the nanoscale, Lu et al. [32] investigated wax precipitation dynamics in shale oil reservoirs during hydraulic fracturing. Their nanofluidic experiments revealed that the fracturing fluid alters phase transitions, with wax accumulating in microcracks and reducing gas mobility. This insight helps optimize the design of fracturing fluids to mitigate formation damage. Meanwhile, Hu et al. [33] advanced our understanding of CO₂ injection dynamics by visualizing nanoscale salt precipitation in shale pores, which revealed dissolution rates slower than classical theory predicts—a critical insight for mitigating formation damage in CO₂-enhanced oil recovery (EOR) projects.

Jia et al. [34] developed a semi-analytical model of the gas–water flow in hydraulically fractured shale that incorporates water invasion effects. Their findings suggest that residual fracturing fluids hinder gas production, highlighting the need for improved flowback strategies. Liu et al. [35] used molecular dynamics to study CH₄ and H₂O interactions in ultra-deep tight sandstone. Their results show that water adsorption significantly restricts the flow of gas, particularly at high water saturations, providing guidance for production optimization in water-bearing formations.

2.2. Geothermal Resource Exploitation Using Low-Energy Technologies

Efficient geothermal energy extraction requires advanced reservoir characterization and stimulation techniques and optimized heat extraction methods. This Special Issue highlights innovative approaches to improving single-well heating efficiency and the performance of enhanced geothermal systems (EGSs). Sáez Blázquez et al. [36] demonstrated the effectiveness of geoelectrical methods in identifying medium-to-low-enthalpy geothermal resources. Their 2D/3D subsurface models revealed fractured carbonate formations with high geothermal potential, significantly reducing the uncertainty of exploration. Zhu et al. [37] conducted simulations using the TOUGH2-BIOT program to analyze EGS reservoir stimulation and compare heat extraction methods. Their results show that horizontal wells achieve higher heat recovery ratios than traditional double-well systems and double-pipe heat exchange configurations, providing a more sustainable solution for long-term geothermal exploitation. Feng et al. [38] evaluated a closed-loop single-well system in Northeast China. By optimizing key injection parameters, they maximized the system’s heat extraction efficiency. Their simulations confirmed the system’s viability for district heating applications in low-temperature environments. Additionally, TOUGHREACT modeling revealed that reducing the injection flow rate, injection temperature, and Mg²⁺/K⁺ concentrations in the injected water can suppress secondary mineral formation and delay near-well reservoir clogging, further improving the system’s longevity [39].

2.3. Intelligent Technologies and Numerical Simulation Innovations for Low-Energy Oil and Gas Development

Artificial intelligence (AI) and advanced numerical modeling are revolutionizing low-energy geo-energy development by enabling more efficient and accurate optimization strategies. Kong et al. [40] developed a hybrid two-stage decomposition–LSTM model for oil production forecasting in complex volcanic reservoirs. Their approach significantly outperforms conventional methods, delivering higher-precision predictions to support data-driven reservoir management. When applied to the Jinlong oilfield, optimized injection–production parameters reduced inefficient fluid cycling, enhancing the efficiency of oil recovery. Liu et al. [41] addressed the challenge of limited early-time pressure data in tight reservoirs by developing a physics-constrained workflow that enhances permeability and skin factor estimation, thereby improving the characterization of tight oil reservoirs. Together, these AI-driven and modeling innovations demonstrate the transformative potential of integrating cutting-edge computational approaches into geo-energy engineering.

3. Conclusions

Many academics from a variety of fields, from natural sciences to engineering, have been researching the recovery of unconventional hydrocarbons, geothermal energy exploitation, and intelligent simulation techniques. New theories and technology are presented in this Special Issue. These new experimental methods, numerical simulation technology, and pilot cases can help readers better understand and be inspired by the cutting-edge technologies being used in the field of low-energy geo-energy development.