Recent Advancements in Petroleum and Gas Engineering

1. Introduction

Oil and natural gas resources are crucial energy sources formed during the geological and biological evolution of the Earth. Due to its lengthy formation period and harsh conditions, oil is generally considered a non-renewable energy source. The global natural gas industry is exhibiting a large-scale upward trend, and an increasing number of scholars have conducted research on engineering and fundamental scientific issues related to natural gas development [1,2,3,4]. Although coal remains a widely used traditional energy source globally, and ongoing research in the academic community focuses on various coal mining-related issues [5,6,7,8], coal, like oil, belongs to the category of fossil fuels and is also a non-renewable resource with limited reserves. Traditional combustion power generation is accompanied by environmental pollution problems, which are difficult to avoid. Due to the substantial reserves of oil and natural gas, they directly or indirectly meet the development needs of countries worldwide in multiple fields [9,10]. Petroleum and natural gas engineering involves the application of scientific theories, methods, and technologies to extract oil and gas resources from subsurface reservoirs using advanced equipment, as well as to process these resources to meet the demand for petroleum and natural gas products.

Following the outbreak of global public health emergencies, the proportion of oil and gas consumption and extraction has decreased. However, the global economy is now showing a gradual recovery, which is likely to prompt countries to increase their efforts in oil and gas extraction. Due to the depletion of shallow resources, oil and gas extraction is gradually moving deeper into the Earth. The deep subsurface environment is characterized by complex geological structures, high temperatures, and high stress conditions [11,12,13,14], and has been a subject of great concern in the scientific research and engineering communities. The complex oil and gas storage environment has a significant impact on the construction of oil and gas wells, reservoir transformation, oil and gas production, and pipeline transportation. Therefore, there is an urgent need for in-depth research and scientific evaluation of key aspects of oil and gas engineering, such as logging, reservoir properties, drilling and cementing, and pipeline safety.

The purpose of this Special Issue is to solicit research on logging and drilling cementing techniques, reservoir physical and mechanical properties, pipeline safety assessment, and high-efficiency oil and gas extraction technologies related to oil and gas engineering. Since the launch of this Special Issue, over 100 renowned scholars have submitted their research. After rigorous review and evaluation by the editorial department and peer experts, high-quality research results were ultimately selected and published in 29 high-level papers in journals such as Applied Sciences, Energies, Fractal and Fractional, Polymers, and Resources, resulting in a very high acceptance rate.

2. Recent Content on Petroleum and Gas Engineering

Scholars have conducted extensive research on important topics related to oil and gas engineering. The high-quality papers published on this subject cover the following key aspects, which will be reviewed in detail.

(1) The physical and mechanical characteristics of oil and gas reservoirs. Han et al. [15] employed low-field nuclear magnetic resonance (NMR) to investigate the saturation behavior of rock samples during the water invasion of gas reservoirs. Their findings indicate that imbibition predominantly occurs in medium to large pores, and that rock permeability, contact surface area, and initial gas saturation are the primary factors governing residual gas saturation. Purnomo et al. [16] employed an enhanced extended elastic impedance inversion method, based on seismic and well log data, to predict the physical characteristics of oil and gas reservoirs. They subsequently verified the accuracy of their results. Yang et al. [17] performed uniaxial compression and Brazilian splitting experiments on rock samples to investigate changes in their mechanical properties and the relationships between various mechanical parameters. Their findings indicate that the mechanical parameters of gneiss samples cored horizontally were greater than those of samples cored vertically. Xie et al. [18] investigated the fractal characteristics of pore size distribution in tight sandstone samples using nuclear magnetic resonance (NMR) techniques. They also determined the relationship between water saturation, pore structure, and NMR fractal dimension. Li et al. [19] proposed a novel hydraulic fracturing technique designed to connect a greater number of fractures and pores, thereby enhancing crude oil production through the fracture network and improving overall operational efficiency. Bai et al. [20] investigated the effect of high ionic strength water (HISW) on improving shale oil and gas recovery, as well as the influence of HISW on shale permeability. They observed a decrease in shale permeability and the formation of cracks under different concentrations of sodium chloride and calcium dichloride.

(2) Logging techniques for oil and gas engineering. Liu et al. [21] employed data oversampling and undersampling algorithms to synthesize a sufficiently comprehensive logging dataset. Subsequently, they trained support vector machine (SVM), random forest (RF), and gradient boosting decision tree (GBDT) models using cross-validation and grid search methods, and evaluated and compared the performance of these models. Based on this analysis, they conducted identification and result interpretation for 18 distinct rock types. Ultimately, they concluded that the aforementioned process can enhance the discrimination of fine-scale lithological intervals within reservoirs across diverse geological settings. Silva et al. [22] investigated the metrological performance of Coriolis meters, ultrasonic flow meters, and positive displacement flow meters under varying conditions of fluid flow rate, temperature, and moisture content. The research findings indicate that the contribution of different parameters to the measurement performance of the system varies depending on the specific measurement technique used. Furthermore, the results reveal that fluid temperature is a significant parameter for all of the evaluated flow measurement approaches.

(3) Extraction techniques for low-permeability oil reservoirs. Li et al. [23] proposed a novel method for determining layered water injection and injection allocation strategies for high-angle wells in low-permeability reservoirs. This method incorporates sand body morphology recognition, seepage unit recognition, and single sand body boundary recognition, while considering factors such as sand body connectivity, reservoir physical properties, and well displacement distance. These factors are relatively straightforward to obtain in engineering practice, thereby enhancing the practicality of the proposed approach. Liu et al. [24] developed submicron cross-linked polymer coils (SCPCs) to enhance the deep penetration ability of profile control agents. They then observed and studied the microstructure of SCPCs using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy. Furthermore, the sealing effect of SCPCs was analyzed based on the observation results, revealing that the effective particle size of SCPCs is 500–800 nm. Finally, the authors concluded that SCPCs exhibit good injectability, sealing performance, and deep penetration ability.

(4) Geological characteristics relevant to oil and gas engineering. Hu et al. [25] conducted a detailed study of a large body of literature and physical simulation experiments on fault lateral sealing. They concluded that when evaluating fault lateral sealing, the clay mineral content and the degree of diagenesis of the fault rocks must be considered as the primary factors. Hu et al. established a correlational relationship between the clay content of fault rocks and burial depth (SGR&H), and proposed a threshold evaluation method for assessing the lateral sealing performance of faults. The researchers then applied the above findings to evaluate the lateral sealing performance of faults in the northwestern, Beier, Urson, and Surnohr areas of the Hailar Basin in China. Sun et al. [26] conducted a comparative analysis of shale gas extraction in the Sichuan Basin and North America. Concurrently, they collected core samples from 32 drilling wells and outcrops, and analyzed the characteristics confronting shale gas extraction in the Sichuan Basin. This review emphasizes that the extraction of diverse shale gas resources not only requires ongoing technological advancements, but also must consider commercial feasibility. Ultimately, this approach can foster the sustained growth of the oil and gas engineering industry.

(5) Safety assessment of oil and gas pipeline infrastructure. Zhong et al. [27] conducted a detailed analysis of the pressure and flow rate changes at each node within the pipeline network, considering the specific characteristics encountered during shale gas transport. They subsequently developed models to describe both the leakage and non-leakage processes occurring in the pipeline network. The primary innovation of this work lies in the proposed method for identifying pipeline leaks through the analysis of internal pressure data. The authors further validated the reliability of this method by comparing it against engineering experimental findings. Zhang et al. [28] undertook a thorough and comprehensive investigation into the concept of vulnerability within the security status of horizontal pipeline networks. The researchers highlighted the significance of quantitative analysis on security indicators and their classification-based evaluation. Furthermore, they emphasized the necessity of establishing and enhancing a security evaluation model grounded in pipeline vulnerability indicators for future applications.

(6) Advancements in technologies aimed at enhancing the quality of crude oil. Hua et al. [29] conducted a comprehensive investigation into the viscosity reduction mechanism of carbon nanotube demulsifiers with varying molecular structures at the oil–water interface. Firstly, the researchers selected carbon nanotubes with different functional groups (NH₂-CNT, OH-CNT, and COOH-CNT) and prepared nanofluids. The microstructure of the materials was then observed using a scanning electron microscope (SEM), and the reasons for the observed decrease in viscosity were analyzed. The findings revealed that as the carbon chain length increases, the conductivity and interfacial tension decrease, while the viscosity reduction rate and dispersion and stability ability increase. Furthermore, the molecular dynamics simulation studies concluded that the diffusion coefficient gradually decreases with increasing carbon chain length, leading to enhanced adsorption at the oil–water interface. This research holds significant implications for the field of heavy oil viscosity reduction and recovery efficiency improvement.

3. Current Trends, Prospective Developments, and Concluding Remarks

By analyzing the current state of research in oil and gas engineering, we can identify the latest advancements and future research priorities. The physical and mechanical properties of reservoirs, as well as the stability of oil and gas extraction in deep and deep-sea environments, are crucial considerations. It is necessary to investigate the evolution of rock fractures in the extreme conditions of deep and deep-sea environments, including the initiation, propagation, and penetration of cracks under the influence of multi-field coupling, tectonic movements, and mining disturbances. This encompasses the study of rock damage and fracture mechanics [30,31,32,33,34,35,36,37,38,39], as well as the mechanical behavior of rocks under various conditions, such as static/dynamic failure, creep failure, stress–seepage coupling, and expansion deformation [40,41,42,43,44,45,46,47,48,49,50]. While previous scholars have researched rock damage, fracture, and failure mechanics across various engineering fields [51,52,53,54,55,56,57], certain factors considered in these studies can be referenced and applied in the context of rock mechanics and engineering. This can be more conducive to predicting and understanding the mechanical behavior of rocks relevant to deep-sea oil and gas extraction. Therefore, it is necessary to consider the inherent characteristics of oil and gas engineering in order to conduct in-depth research on oil and gas operations in deep-sea environments. It is important to note that research is also required on the environmental impacts arising from the development of oil and gas engineering. Additionally, it is necessary to develop drilling, cementing, and extraction equipment that is suitable for the extreme geological conditions found in deep-sea and deep-Earth environments in order to improve the efficiency of oil and gas recovery in these settings. Furthermore, with the advancements in computer technology, electronic information technology, and data acquisition and processing capabilities, the research and development of equipment should focus on intelligence and automation. The overall development of oil and gas extraction engineering should prioritize intelligence, automation, high precision, high efficiency, and coordinated operations.

The guest editors and scholars provided concise summaries of the key highlights from these works, and emphasized their significance in advancing the field of oil and gas engineering. The papers published in this topic cover the latest cutting-edge fields of oil and gas engineering, including oil and gas reservoirs, reservoir logging, low-permeability oil and gas reservoirs, reservoir geological characteristics, pipeline safety, and crude oil upgrading and refining. These research results and valuable insights shared by the authors can drive progress and inform the future research direction in the field of oil and gas engineering. Therefore, this topic is of great importance and relevance for the advancement of oil and gas engineering.

In summary, the guest editors and authors are deeply grateful for the valuable contributions of all the colleagues and reviewers who have supported this publication. We hope that, in the future, scholars will continue to conduct research in the cutting-edge fields related to oil and gas engineering, and we encourage them to submit their results to this topic. These related research directions include, but are not limited to, oil and gas field development planning and production technology; oil and gas well fluid mechanics, rock mechanics, and oilfield chemistry technology; theory and methods of reservoir characterization and geological modeling for development; percolation theory and reservoir numerical simulation; theories and methods of oil and gas field development; theories and technologies of enhanced oil recovery; multiphase pipeline flow, oil and gas field gathering and transportation, and oil and gas treatment technology; theoretical and technical aspects of reservoir damage and fracture failure mechanics in deep-sea environments; the application and development of intelligent and automated technologies in oil and gas engineering; and the advanced research and development of equipment and technologies for oil and gas engineering.