Energy Exploration & Exploitation

The Jin77 well block is a highly promising area in the Hangjinqi region of the Ordos Basin. However, there were few wells and little geological research in this area. In order to better understand the sequence and depositional characteristics of the Xiashihezi Formation 1 Member (also known as the He1 Member) in the Jin77 well block, as well as to describe the sedimentary microfacies distribution of the development Sublayer unit, a thorough integration and calibration of core, logging, and seismic data were conducted. By analyzing the comprehensive response characteristics of logging and seismic data, we were able to subdivide the strata of the Xiashihezi Formation and establish a high-frequency sequence framework within the study area. The He1 Member was found to consist of 4 Sublayers, each with a consistent thickness. Based on the analysis of fine cores, it was determined that the dominant sedimentary type in this area was that of a wandering, shallow braided river. This conclusion was supported by the observed lithofacies marks, vertical facies sequence, and horizontal distribution of sandstone bodies. By combining the analysis of logging and seismic data with the results of the detailed Sublayers subdivision, the relative isochronous boundaries were able to be identified. The use of geophysical slicing technology, along with well and seismic data, it was allowed to effectively characterize the microfacies boundary of the braided river within the H1-1 sublayer unit. The findings show that the H1-1 sublayer contains approximately four to five braided river channels, with widths ranging from 1.5 to 6.5 km. These results provide valuable information for reservoir prediction and the detailed description of Sublayer units.

Fine-grained sediments, capable of being transported into deep lacustrine basins via gravity flows, can form potentially high-quality shale oil reservoirs. Therefore, it is crucial to investigate the sedimentary characteristics of various fine-grained gravity flow sedimentation processes within lacustrine basins. This study examines the sedimentary features of fine-grained gravity flow deposits in the 7₃ sub-members of the Yanchang formation in the Longdong area of the Ordos Basin, utilizing core and thin-section observations, and well-logging characters. The findings reveal that the Chang 7₃ sub-member experienced a deep-lacustrine environment, where nine distinct lithofacies assemblages emerged under different sedimentation processes: the fine-grained quiescent sedimentation assemblage (LA1), the fine-grained mudflow sedimentation assemblage (LA2), the fine-grained debris flow sedimentation assemblage (LA3), the fine-grained slump sedimentation assemblage (LA4), the fine-grained turbidity currents sedimentation assemblage (LA5), the fine-grained concentrated density flow sedimentation assemblage (LA6), the fine-grained transitional flow sedimentation assemblage (LA7), the fine-grained surge-like turbidity flow sedimentation assemblage (LA8), and the fine-grained quasi-steady turbidity current sedimentation assemblage (LA9). These lithofacies assemblages were generated under three primary conditions: tranquil environments, slump events, and flood events. A comprehensive sedimentary model has been constructed based on the distribution of the siltstone bodies, illustrating the sedimentary processes and the spatial evolution of these lithofacies assemblages. The fine-grained sediments deposited in Chang 7₃ exhibit a notably high total organic carbon (TOC) content. The extensive distribution and the presence of multiple interbedded layers of organic matter-rich shale and fine-grained siltstone create a conducive environment for the generation and preservation of shale oil within the Chang 7₃ sub-member in the Longdong area.

The analytical approaches including thin-section petrography, X-ray diffraction, scanning electron microscopy energy dispersive spectrometer, and high-pressure mercury intrusion porosimetry were conducted on the sandstone reservoirs in the Lishu fault depression to investigate the diagenetic alteration and their impacts on pore structure and reservoir quality. The results show that correlations between diagenetic processes and reservoir properties are observed. Six diagenetic facies, namely the strong compaction with moderate cementation facies (SCMCF), weak dissolution with cementation facies (WDCF), moderate cementation with feldspar dissolution facies (MCFDF), moderate cementation with residual intergranular pore facies (MCRIPF), moderate cementation with fracture facies (MCFF), and moderate cementation with mixed dissolution facies (MCMDF), were classified through detailed examination of microscopic petrography. Variations in pore volumes, pore size distribution, and pore fractal dimensions, alongside their influencing factors, were analyzed to elucidate the impacts of diagenetic processes on the reservoir quality of tight sandstones. The diagenetic coefficient and mineral composition are considered critical determinants of pore structure. Specifically, SCMCF and WDCF are regarded as unfavorable diagenetic facies. MCFDF and MCRIPF are categorized as moderate diagenetic facies. Conversely, MCFF and MCMDF are considered favorable diagenetic facies. The SCMCF and WDCF suggest a relatively low heterogeneity, Conversely, the MCFDF, MCRIPF, MCFF, and MCMDF show obvious reservoir heterogeneity and low pore-throat connectivity. The fractal properties of the WDCF, MCFDF, MCRIPF, and MCMDF are obvious, indicating relatively complex pore structures. This article provides insights into the relationships among the diagenetic facies, pore structure, fractal dimension, and reservoir quality of tight sandstones in the Lishu fault depression, in addition, has significance for the reservoir evaluation and exploration of tight sandstone gas the rift Basins.

To deepen the understanding of chlorite and laumontite mineral characteristics within the Lower Wuerhe Formation in the Madong area of the Junggar Basin, a detailed investigation was carried out using thin sections, electron probe microanalysis (EPMA), and X-ray diffraction (XRD). Through this multi-method approach, their chemical compositions, occurrences within thin sections, and the impacts on the physical properties of the reservoir were illustrated. The results indicate that the chlorite minerals exhibit a trioctahedral crystal structure and are found in four distinct forms: as pore linings, grain coatings, pore fillings and chlorite pseudomorph. They belong to the iron-magnesium transitional type with a magnesium-rich composition. The octahedral sites primarily feature Fe substituting for Mg, with an Al/(Al + Mg + Fe) ratio ranging from 0.25 to 0.37. Chlorite formation is attributed to the alteration of argillaceous rocks and mafic rock transformations, with significant material input from the hydrolytic dissolution of tuffaceous volcanic materials and interconversions among clay minerals. Chlorite has been shown to significantly enhance reservoir physical properties, contributing to the development of high-quality reservoirs. Laumontite occurs in three states: crystalline aggregates, filling materials, and through replacement processes. Laumontite crystalline aggregates are often surrounded by debris, which promotes their formation. In its filling state, laumontite coexists with chlorite, calcite, and other minerals, competing for material sources, which can partially inhibit its formation. Replacement-type laumontite forms mainly by replacing feldspar and rock fragments, leading to a high Si/Al ratio and acid resistance, making it less susceptible to dissolution. However, the effect of laumontite on reservoir properties is relatively limited compared to that of chlorite. The diagenetic environment of the Lower Wuerhe Formation varies with increasing burial depth, transitioning from alkaline to acidic and then back to alkaline conditions.

The rock mass damage and failure induced by underground coal resource exploitation are strongly influenced by the confining pressure unloading (CPU) rate. However, the impact of CPU rate as a sole variable remains inadequately understood. This study utilizes discrete element numerical tests to explore the influence of CPU rate on the mesoscopic fracturing mechanism of sandstone. Homogeneous three-dimensional models with consistent mesoscopic parameters and constant axial pressure are subjected to varying CPU rates. By isolating the CPU rate as the sole variable, macroscopic failure patterns, mesoscopic damage evolution, and energy density distributions are investigated. The numerical results are validated against existing physical experimental results, confirming the rationality of the discrete element model parameters. The results show that lower CPU rates induce multistage, sudden, and progressive failure, characterized by stepwise increases in energy density, more abrupt fractures, and enhanced mobilization of local load-bearing capacity. The defined medium CPU rate results in distinct physical responses, attributed to particle rearrangement driven by unloading rate. Particle displacement is identified as a quantitative indicator of rock damage. The results underscore the importance of isolating the CPU rate effect to improve the understanding of rock fracturing mechanisms and associated physical properties.

The Moesian platform has been extensively studied both from the tectonic point of view and from the perspective of its sedimentary bed which is rich in hydrocarbon resources. Extensive research has shown that the Moesian platform consists of Paleozoic sedimentary formations having their accouchement in four cycles, which according to in the Ordovician, Silurian, lower Devonian (dark and leaden argillites), upper Devonian (bituminous dolomites with pyritization) and mid-Triassic (muschelkalk) period, the oil and gas genesis took place. Moreover, such resources have been traced in rocks of all ages, including in the ones from the fourth sedimentation cycle. The present paper offers insight into the lithology and petrographical features of the Sarmatian stage since there is a lack of detailed petrographic published data regarding this topic. The study highlights the lithology, offering detailed petrographical features for the Sarmatian on a petroliferous structure located in the eastern part of the platform. Fossil and palynological correlations have been employed by numerous authors, resulting in a lack of focus on lithological correspondence, which is mainly due to the absence of scarce presence of available data on the Sarmatian. We therefore hold firm belief that our study could help develop future links and serve as a knowledge database.

Mercury (Hg) is a critical pollutant in coal deposits, yet its sources and enrichment mechanisms remain debated. Mercury concentrations detected in ancient sedimentary deposits have frequently been employed as an indicator of volcanic activity, notably those associated with eruptions from large igneous provinces. Yet, this correlation requires careful evaluation, as multiple Hg sources may contribute to its enrichment in sedimentary environments. Potential Hg sources include volcanic emissions, hydrothermal fluids, anthropogenic activities, and other geogenic inputs. The examination of mass-dependent fractionation and mass-independent fractionation in laboratory experiments has increased the feasibility of employing mercury isotopic methodologies to deduce the origins of deleterious trace elements in environmental systems. The harmful trace elements Be, F, V, Cr, Cu, As, Se, Mo, Tl, Pb, U, and Hg show abnormal enrichment in the stratigraphic samples JY-3-1 and JY-3-9 from the Tengnan Coalfield. In the low-temperature hydrothermally altered coal seams of the Jinyuan Mine in southwestern Shandong Province, sulfide and clay minerals are likely the main carriers of mercury. This study aims to indirectly infer the sources of other harmful trace elements strongly correlated with mercury enrichment. A nuanced interpretation of Hg isotope data is necessary due to the complexity of multiple-source mixing, post-depositional modifications, and isotopic fractionation processes. Through the integration of mercury isotope analysis with a suite of analytical techniques, including geochemical analysis, mineralogical studies, and geological surveys, the results indicate that the sources of harmful trace elements in the No. 3 coal of the Jinyuan Mine are predominantly influenced by volcanic activity, atmospheric precipitation, and terrigenous sediment input, with a minor contribution from coal-forming plants. The application of Hg isotopes allows for more effective regulation of high-Hg coal usage, enabling policymakers to implement stricter emission controls, promote cleaner coal technologies, and establish Hg-specific air quality standards.

The study of coal seams provides valuable insights into the environmental changes that have occurred throughout Earth's geological history. Coal formation was notably widespread during the Jurassic period in mid-latitude East Asia. To reconstruct the paleoenvironmental conditions prevailing during the formation of peat in the Turpan-Hami Basin, China, we conducted a comprehensive study of 44 Middle Jurassic coal samples. Our investigative approach encompassed coal petrographic analysis, and gas chromatography-mass spectrometry to compare our findings with existing literature. Biomarkers from steranes and diterpenes suggest OM in coals of No. 4 seam predominantly originated from terrestrial higher plants, with conifers being one of the important sources of OM. Vitrinite reflectance, hopane, and sterane maturity biomarkers indicate that most of the samples exhibit low thermal maturity. Previous studies suggested that the No.4 coal seam formed in a saline water environment based on trace element indicators. However, this study, based on biomarker analysis (low gammacerane index, high Pr/Ph ratio, and low sulfur content), suggests that peat accumulation occurred in freshwater environments. The anomaly of element indicators in previous studies may be attributed to the introduction of trace elements from overlying strata into the coal seams via surface (groundwater) water or hydrothermal fluids. Since the vegetation and depositional environments indicated by biomarkers are more consistent with the Jurassic geological setting, biomarkers offer a more reliable indication of depositional environment compared to trace element indicators.

This study, based on a case from the 1314 working face of Xiaoyun Coal Mine, provides an in-depth analysis of the stress and velocity field characteristics of waterproof coal pillars under different porosities during water inrush events. The research emphasizes the significant impact of water inrush on the stress field distribution of coal pillars. Simulation results, validated by field data, reveal that the highest stress concentration occurs on the side of the coal pillar adjacent to the goaf, with the stress distribution under water inundation conditions exhibiting greater irregularity. The findings not only enhance the understanding of stress variations in coal pillars during water inrush events but also offer valuable insights for coal pillar design and monitoring strategies. This research provides critical theoretical support and technical guidance for the safe design and dynamic monitoring of water inrush disaster prevention in coal mines.

Due to its ability to address power outages, smart grids are regarded as one of the energy solutions in the modern world. Because they integrate free energy resources into the distribution network and save a significant amount of energy. Electric buses and other electric cars can now be used as both a source of energy and a mode of transportation. In this article, we proposed an integrated decision model for energy management and vehicle routing, which enables the dispatching of electric buses in an adaptive manner to meet transportation and energy demands. This model is the first of its kind, as there is no literature that addresses transportation and energy issues simultaneously, under spatial and temporal complexities, which is the main contribution of this model. This study assumes that the electric bus has various distributed energy resources installed on it, such as a battery and a solar panel. Electric buses use electricity while they travel in order to carry people and deliver energy to other places. A mixed-integer linear programming method has been used to model and solve this problem. This study used performance metrics such as energy expenses, carbon footprints, and traffic volume. The results of the simulation demonstrate that the electric bus network offers greater flexibility when it comes to distributing energy loads among various sites at various times. Since, it can save up to $40,000 in operating costs, reduce CO 2 by up to 40 tons, and cut down on traffic by 16k automobiles.

The thermophysical properties of rocks are identified as basic physical parameters for the exploitation and utilization of hot dry rock (HDR) geothermal resources. Given that reservoirs in a HDR system are subjected to a certain temperature and pressure, investigating the impacts of temperature and pressure on the thermophysical properties of rocks holds great significance. This study investigated the granite samples from the Tengchong area, Yunnan Province, China. Using laboratory tests combined with simulations, this study explored the impacts of temperature, pressure, and the combination of both on the thermal conductivity and diffusivity of granites. The results indicate that in the uniaxial pressure range of 0 to 42.2 MPa, as the uniaxial pressure increases, the thermal conductivity of the granites tends to increase nonlinearly, while their thermal diffusivity has no obvious correlation with the pressure. In the temperature range of 25 to 300°C, as the temperature increases, both the thermal conductivity and diffusivity of the granites tend to linearly decrease, with a linear relationship existing between the thermal conductivity and diffusivity. Using these findings, this study developed a prediction model for the thermal conductivity of granites under the combined effects of temperature and pressure. Additionally, based on the computed tomography (CT) scans, this study established core-scale heat transfer models focusing on minerals using the COMSOL Multiphysics finite element analysis (FEA) software. The model has a certain reliability in the prediction of thermal conductivity at 25∼300°C, and the error is less than 15% at 25∼200°C.

Torsional impactor is widely used in deep and ultra-deep wells because it can suppress stick–slip vibration and increase ROP. As the direct factor affecting torsional impactor effect, it's working parameters study is still not sufficient. In order to evaluate the effect of torsional impactor, considering the high-frequency torque provided by torsional impactor, a dynamic model of torsional vibration of drillstring is established, and by compiling the calculation program, and solved by The fourth–fifth Runge–Kutta, the influence of main working parameters of torsional impactor on stick–slip vibration is analyzed. The results show that: The torsion impacter can effectively reduce the stick–slip period of drillstring, thereby suppressing the stick–slip vibration and increasing the ROP; when the torsional impact load is low, increasing the torsional impact load can reduce the stick–slip period and even eliminate the stick–slip vibration, However, when the stick–slip disappears, increasing the torsional impact load has small effect on the torsional vibration. Increasing the impact frequency can suppress the stick–slip vibration and improve the stability of the drillstring during rotation. The results provide reference significance for the selection of working parameters of torsional impactor.

Worldwide energy demand is increasing exponentially, presenting significant challenges for existing power generation systems to meet this demand. Enhancing energy efficiency has become critical for reducing consumption and addressing the ongoing environmental crisis. Consequently, there is a need for smart control systems that optimize system costs and improve efficiency. Because of the introduction of smart grids, customers can now participate in demand-side management and integrate renewable energy sources (RESs). Electricity consumption during peak hours often leads to increased grid demand and higher costs. However, the integration of RESs enables consumers to operate appliances during peak hours, thereby reducing reliance on grid power. Therefore, residential load management seeks to reduce power peaks and electrical energy costs. In home energy management systems (HEMS), appliance scheduling is crucial because it continually monitors appliance usage, ensuring that energy supply and demand are balanced. This research aims to optimize power usage by reducing peak loads and electricity costs through the integration of RESs, such as solar or photovoltaic (PV) systems, while considering grid limitations, PV capacity, appliance ON/OFF schedules, and time-of-use tariffs. A genetic algorithm (GA) based optimization technique was employed to evaluate the performance of a HEMS and validated with particle swarm optimization (PSO) technique under identical initial conditions for each appliance and their corresponding energy pricing over different periods. The results show that GA achieved a 48% cost reduction compared to PSO, with significant peak load reduction and improved energy optimization when integrated with PV systems. GA also demonstrated better appliance scheduling, with appliances in the “ON” state for 82% of the time, compared to 52% with PSO.

In order to reduce energy waste caused by insufficient absorption capacity, improve the stability and reliability of the wind and solar energy storage system, reduce power costs, reduce greenhouse gas emissions, and enhance environmental benefits. A new optimization method for vanadium redox batteries that considers the wind and solar absorptive capacity is studied. The outputs of the wind worm wheel, photovoltaic, and new vanadium redox batteries in the wind–solar vanadium redox battery are calculated and analyzed. Based on the calculation results, the wind light memory capacity majorization arrange blueprint is constructed, and the impersonal ability of the blueprint is to determine the maximum total consumption of recyclable energy, the highest energy utilization efficiency, the minimum cycle energy of energy memory battery and the minimum cycle fever memory of fever memory tank, and the minimum amount of wind and light discarded. After the relevant constraints are designed, the upgraded quantum particle flock majorization arithmetic is used to solve the impersonal ability to obtain the arrange majorization results of the new vanadium redox battery. The test results show that after the majorization of energy memory arrange by this method, the maximum values of distributed generation absorption ratio, load peak valley difference degree, and load fluctuation degree are 0.74, 0.15, and 0.17, respectively; energy utilization efficiency reaches 75.5%; the change of the state of condition of the vanadium redox battery is relatively gentle, and the fluctuation range is between 0% and 60%; the effective wind and solar absorptive capacity of each node is above 11 GW/h.

The ability to treat saltwater to make it suitable for human consumption has long been sought by mankind. More than three-quarters of the earth's surface is covered with saltwater. Although this water is important for some forms of transportation and fishing, it contains too much salt to sustain human life or agricultural activities. One way to desalinate water is to use solar energy-based technologies. One of these technologies is the use of a solar device to evaporate and condense water, along with the generation of electricity through a transparent photovoltaic panel, providing freshwater. The current work focused on developing a simple solar still with low-cost materials that can be built by anyone, anywhere. In addition, the study presented three-dimensional multiphase CFD models for a single-slope solar still. Computational modeling using ANSYS 15 enables precise simulation and optimization of this integrated solar system, maximizing its overall efficiency and output. This dual-purpose solar energy utilization offers a pathway to provide both clean water and electricity to communities in remote or resource-constrained regions, thereby enhancing their quality of life and promoting sustainable practices. Simulation results indicate that increasing the saline water temperature from 60°C to 70°C results in a 67% increase in water production at a wind speed of 3 m/s. A further increase in temperature from 80°C to 90°C leads to a 141% increase in water production under the same wind conditions.

The application of multi-generation systems has seen significant growth in recent years. This research explores an innovative Rankine organic cycle that generates electricity, hydrogen, and potable water by integrating geothermal and heat recovery as energy sources. The cycle's efficiency is assessed in two configurations: utilizing geothermal energy and not utilizing it. Calculations show that the highest exergy destruction, at 32.5%, is linked to the proton electrolyzer membrane (PEM). Additionally, the lowest exergoeconomic factor, at 7.9, is found for the PEM. The cycle generates 1.81 L/s of hydrogen and 4.52 kg/s of desalinated water. Increasing the temperature of the geothermal source from 125 °C to 161 °C leads to a 30.2% increase in hydrogen production and an 18.1% increase in desalinated water production. If geothermal energy is not used and all energy comes from heat recovery, carbon dioxide emissions will increase to 71%.

This study presents a comprehensive analysis of an organic Rankine cycle (ORC) integrated with a hybrid solar-geothermal energy system. The research aims to evaluate the thermodynamic performance and exergy efficiency of the hybrid system and compare it with a standalone solar ORC. The problem is approached by analyzing exergy destruction within key components, using the entropy method, and evaluating the impact of different working fluids. For the standalone solar ORC with a 1 MW turbine, the turbine and condenser were identified as the main sources of exergy destruction, contributing 40% and 25%, respectively. In the hybrid solar-geothermal ORC, the solar collectors were the dominant source of exergy destruction, contributing 58%, while the turbine's share was reduced to 10%. The use of R245fa improved the overall efficiency by up to 3%. A validated Simulink model was developed, confirming the reliability of the simulation results. The findings highlight the potential of hybrid systems in improving energy efficiency for small- to medium-scale combined heat and power applications, with future work focusing on optimizing operational parameters and exploring additional working fluids.

The increasing disturbances in power system networks present significant challenges to electrical power engineers, often leading to a loss of synchronism in grid-tied generators. It is important to ensure voltage, angle, and frequency stability in power system for efficient grid operation and a sustainable power supply. This paper investigates transient stability enhancement in multi-generator system using an artificial neural network (ANN)-based control technique. The conventional high-voltage direct current (HVDC) systems are based on a fixed proportional integral controller parameters to function efficiently, but the proposed ANN-based technique dynamically adjusts the thyristor firing angle in real-time to improve system stability. This intelligent control mechanism enhances transient stability by optimizing power system responses based on real-time operational data. The effectiveness of the proposed method is tested on a real 330-kV, 40-bus Nigeria transmission network, modeled in Power System Analysis Toolbox. The Newton–Raphson power flow method is employed to determine the base-case characteristics of the network. To achieve stable system operation, the voltage magnitude of a transmission system must fall within the statutory limit of 0.95–1.05 per unit (pu). However, power flow studies indicate a significant low-voltage profile of 0.70 pu on the network. Implementing the ANN-based HVDC system, three-phase faults are cleared within 2 ms, demonstrating a significant improvement compared to the 3-ms critical clearing time achieved using conventional method. Additionally, the ANN-based controller enhances voltage stability, achieving a minimum voltage magnitude of 0.98 pu, representing a 27.8% improvement over the conventional approach. The results confirm that the proposed ANN-based HVDC system offers superior transient stability performance by dynamically adjusting the system response, ensuring better fault ride-through capability and improved voltage profile. The findings highlight the potential of ANN-based controllers in improving transient stability in modern power systems.