Abstract: In response to the potential hazards of spontaneous combustion and gas in large-scale goaf areas, the risk factors such as coal spontaneous combustion status, gas status, and ventilation status in goaf are analyzed. And simulation software is used to simulate the internal flow field of large-scale goaf, and the distribution law of its internal flow field is obtained. Then, the index evaluation method is used to conduct special evaluations of spontaneous combustion risk and gas risk in large-scale goaf areas. Finally, based on the determination of the warning indicators, levels, rules, and warning signals for large-scale goaf hazards, the results of the special evaluation of goaf hazards are transformed into corresponding warning signals for release, forming a set of large-scale goaf hazard analysis and evaluation technology system. Read More

Abstract: This study aims to address the technical challenges encountered during drilling and completion of complex-structure wells, improving the efficiency and safety of casing design. Complex-structure wells, such as horizontal wells, multilateral wells, and extended-reach wells, impose higher demands on casing design due to their intricate geological conditions. Traditional design methods, often reliant on empirical formulas and simplified assumptions, struggle to meet the evolving needs of modern drilling technology. Therefore, this research is dedicated to developing a novel optimization method for casing design in complex-structure wells to enhance drilling efficiency and economic benefits. The study employs a combination of numerical simulation and optimization algorithms. Initially, a comprehensive mathematical model is established, factoring in formation properties, drilling fluid performance, and borehole stability, to forecast drilling performance under various casing designs. Genetic algorithms are then utilized to optimize casing parameters, seeking the optimal casing design that meets safety and economic constraints. The effectiveness of the optimized solution is validated through field trial data and compared against conventional design methods. It is found that the optimized casing design significantly reduces drilling risks, accelerates drilling speed, and cuts drilling costs. Specifically, under the premise of maintaining borehole stability, the optimized scheme decreases drilling time by an average of 15% and reduces drilling costs by approximately 10%. Moreover, the proposed method exhibits strong adaptability, capable of being flexibly adjusted according to different well types and geological conditions, providing a robust technical foundation for efficient drilling of complex-structure wells. Read More

Abstract: Natural gas is known as a clean energy source due to its environmental benefits and economic viability, widely used in both industrial and residential sectors. Liquefied natural gas (LNG) is characterized by its small volume and low-cost transportation over long distances (by ship), with about 25% of international trade conducted using LNG. In recent years, China's LNG supply has been steadily increasing, and it is expected that by 2040, China's demand for LNG will exceed 15% of the global total. LNG is a low-temperature (−162°C) liquid mixture formed by purifying natural gas to remove acids and water, followed by low-temperature condensation. LNG receiving stations typically use seawater heating to vaporize LNG into gaseous natural gas for export, with the large amount of cold energy released during vaporization absorbed by seawater and discharged into the ocean, approximately 830 kWh/kg. Based on China's receiving capacity in 2018, the cold energy from LNG was equivalent to 2.07 billion kWh, and it is projected to reach 5.98 billion kWh by 2023, indicating a rich resource of cold energy. As China imports significant amounts of LNG, the comprehensive utilization of LNG cold energy becomes increasingly important. Read More

Abstract: In addition to methane, liquefied natural gas (LNG) typically contains valuable light hydrocarbons such as ethane, propane, and butane. Establishing LNG receiving stations for imported LNG can effectively alleviate regional energy supply-demand conflicts, optimize energy consumption structures, promote sustainable regional economic development, and improve ecological environments. The technology for long-distance low-temperature pipeline transportation of LNG facilitates the efficient transfer and cascading utilization of the cold energy contained in LNG, allowing for deep coupling with cold networks and natural gas pipelines, thereby promoting the integrated development of LNG, cold energy, and natural gas transportation. This paper systematically summarizes the current status of LNG long-distance low-temperature pipeline transportation technology, cold energy cascading utilization technology, pipeline regulation technology, and multi-network integration technology. It analyzes the key challenges these technologies face under new strategies and looks ahead to future development trends, aiming to provide scientific insights and directions for the application of LNG long-distance low-temperature transportation and multi-network integration in China. Read More

Abstract: In order to carry out the geological characteristics, evolution law and other scientific research of the deep strata in the extra-deep well, it is necessary to carry out the coring operation in the extra-deep depth. However, with the increase of drilling depth, the force of drill string in the underground becomes more and more complicated, and there is contact collision between the core and the core after the core tool is bent, which makes the core broken. Clarifying the dynamic behavior of the BHA during the extra-deep well coring process is helpful to obtain a more complete core. Therefore, this paper adopts the simulation analysis method to simulate the coring process of the extra-deep well with a 163.5mm diamond bit and a 140mm corer under the real drilling hole trajectory. The stress, eddy motion and the contact between the inner barrel of the core tool and the core of the lower 1000m drill assembly are analyzed. The results show that the hole expansion rate of coring bit is 2.5% in the process of low bit weight and low rotational speed. When the core is 8m, the core barrel is under compression, bending and torsion, and under the restriction of the centralizer and the core hole, the middle and upper part of the core tool bend greatly, and the contact degree with the core is high, and the larger contact force is easy to cause the lower core to fracture. Read More

Abstract: Coal mining can create a large number of abandoned areas, which contain rich coalbed methane resources. The adsorption principle of the residual gas left in the abandoned coal seam is an important part of the coalbed methane resources. The adsorption principle is of great significance for the evaluation of coalbed methane resources in abandoned coal seams. However, due to the complex environment in abandoned coal seams, the factors affecting the adsorption of residual gas in abandoned coal seams are also complex. Among them, water is an important factor that affects the adsorption of residual gas in abandoned coal seams. The study on the adsorption of residual gas in abandoned coal seams with different water infiltration conditions is less. Therefore, a block coal water-flooding gas adsorption device was developed for the study of block coal gas adsorption, and the adsorption rate of block coal gas under different water infiltration conditions was determined experimentally. Read More

Abstract: Parks are important carriers of urban blue-green space and cultural services, which are vital to beautify the city and improve the quality of life of residents. Constructing a questionnaire system for cultural services in blue-green spaces is of great significance for evaluating and studying the supply of regional cultural services and quantifying residents' cultural needs. In this paper, we take Zhengzhou city park as the evaluation object, and based on AliCloud server ECS and WebGIS technology, combined with drone orthophoto and real-life three-dimensional model, we make the questionnaire survey system of blue-green space cultural service to collect residents' social value preference and suggestions for the park. Respondents enter the system through any device with internet access, browse park pictures and profiles, and participate in the online questionnaire survey, and the collected data on residents' value preferences can be used to assess the value of the park's cultural services by methods such as the SolVES model. The system solves the shortcomings such as heavy workload and low response rate of distributing questionnaires in the field. The system integrates a variety of digital technologies and improves the questionnaire survey method, which can effectively improve the efficiency and quality of the questionnaire survey and analyze the problems and deficiencies of the park with the opinions of the respondents, so as to provide the management with references for optimization and standardization, and to promote the enhancement of the quality of cultural services. Read More

Abstract: This study introduces the OVT (Offset Vector Tile) domain processing technology to improve the accuracy of small structure detection in 3D seismic exploration of coalbed methane in the Heshun-Hengling block in China. The OVT technology optimizes wide azimuth seismic data processing through steps such as facet division, five-dimensional regularization, pre-stack time migration, and azimuthal anisotropy correction. The results show that OVT processing retains azimuth information, enhancing the ability to reflect stratum changes with azimuth; azimuthal anisotropy correction improves the resolution of the profile. The profile after OVT processing has a natural waveform, good continuity of the phase axis, and a wide frequency band, meeting the requirements of the “Coalbed Methane Seismic Exploration Specification”. It demonstrates the advantages of OVT technology in imaging complex geological structures, providing a new perspective for seismic exploration. Read More

Abstract: In the progress of realizing green development and transformation, many difficulties exist in Sichuan Province, such as low level of ‘carbon unlocking’, unbalanced development of ‘carbon unlocking’ among regions, and insufficient systematic coordination and governance capacity. So, this paper from technology, system and industry and other aspects, based on the ‘double carbon’ goal of Sichuan Province, to construct the ‘carbon unlocking’ mechanism with the characteristics of Sichuan Province, to create a ‘multi-body-multi-path’ synergistic mechanism. This will help to promote green technology innovation and help to achieve the ‘dual-carbon’ goal on schedule. Read More

Abstract: Abandoned mines have caused many landscape ecological problems to urban development, This paper analyses the causes of the problems from the concepts related to mineral resources and mine wasteland, and briefly describes the concepts related to ecological restoration, combining with two cases of mine restoration, discusses the effective measures for the restoration of abandoned mines, which are mainly as follows: the management measures for slopes; the tailings management measures; the soil grassroots improvement; phytoremediation of heavy metal pollution in mines; restoration of water resources in mines and microbiological restoration measures. Read More

Abstract: Diamond core bits are essential tools for coring operations in deep formations during oil and gas drilling projects. By establishing a cutting mechanics calculation model for diamond core bits, this study investigates the changes in bit load and torque under the influence of key factors such as bit cutting structure, rock strength, and diamond distribution density. This research is significant for optimizing bit structure, enhancing coring drilling efficiency, and prolonging bit lifespan. This paper conducts modeling analysis of the cutting element loads for various shaped diamond particles, including rectangular, triangular, cylindrical, and spherical shapes. Based on this, a cutting mechanics calculation model for axial and tangential forces of granular spherical diamonds is established using the fundamental principles of elastoplastic mechanics. Consequently, a set of methods for calculating and analyzing the working loads of diamond core bits is developed. The findings of this paper provide a theoretical basis for studying the rock-breaking mechanism of diamond core bits, evaluating drilling efficiency, and optimizing tooth arrangement structures. Read More

Abstract: Acoustic domestication type of marine pastures are generally established in shallow waters with water depth not exceeding 200 m. In order to study the effect of acoustic domestication, this paper aims to investigate the environmental noise in the shallow waters of the sea. Unlike the stable deep sea environment, the environmental noise in the shallow sea is extremely complex, which has a direct impact on the effect of acoustic domestication. In this paper, in order to study the marine environmental noise, a hydroacoustic signal processing system is established, which is divided into two parts: the hardware part and the software part; the hardware part is mainly for signal sampling, and the software part is for signal processing. The hardware part of the hydroacoustic signal processing system includes three parts: acoustic-electric conversion, intermediate processing and signal recording. The study of ship noise showed that the fishing boat is about 5m long, with a power of 60hp, and passes about 10m away from the hydrophone, and it is more than 10dB higher than that without a ship, when there is a ship passing, in which the 400Hz is 17.82dB higher. Measurements of ocean ambient noise at different depths show that the noise decreases with depth, but when close to the seabed, the noise decreases with depth due to the reflection effect of the seabed on the sound and the biological noise of the seabed. Read More

Abstract: The effects of climate change on glaciers, in terms of their scope and conditions, have become increasingly apparent, with serious consequences for various ecosystems, affecting hydrological and terrestrial factors. This paper reviews the existing literature on the complex interaction between glacier retreat and vegetation distribution. In the short term, glacier retreat may promote vegetation expansion by increasing water supply, while in the long term, drought may occur due to glacier depletion, adversely affecting vegetation growth. In addition, glacial meltwater is usually cooler, so the melting of glaciers will also affect the temperature of water resources, thus affecting the growth of vegetation to a large extent. On the one hand, glacier ablation results in the transfer of glaciated rocks and moraines from the glacier surface to the pericardial zone. The former is rich in organic matter and minerals, while the latter can provide parent rock, promote soil development, increase soil nutrients, and expand vegetation colonization. On the other hand, melting glaciers can cause soil erosion and soil depletion, which is not conducive to the growth of vegetation. Melting glaciers will lead to more surface runoff, which will affect soil erosion and even the formation of new terrain, all of which are associated with vegetation growth. The increasing concentration of carbon dioxide in the atmosphere has led to greening on a global scale, creating positive and negative feedback loops in different regions. Therefore, the glacier ablation and its pathways and sub-pathways are affected, so the glacier ablation seriously affects the vegetation distribution. Overall, the effects of glacial retreat on vegetation distribution are very complex. As glaciers continue to retreat globally, understanding these dynamics is critical to predicting future changes in vegetation distribution. Read More

Abstract: The power battery system is one of the high-risk components for new energy vehicles, and standardized operation and maintenance is one of the effective measures to improve the safety of new energy vehicles. The operation and maintenance of the power battery system includes daily operation, first level maintenance, and second level maintenance. A combination of practical research and theoretical analysis is adopted to confirm different maintenance tasks, job contents, and technical requirements, in order to improve the standardization and safety of operations. Fault mode analysis is a continuation of fault maintenance and provides practical basis for the design and process improvement of power battery systems. Read More