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Articles 91 - 120 of 4757

Full-Text Articles in Physical Sciences and Mathematics

An Experimental Study Of Factors Influencing Gas Seepage In Confined Broken Anthracite, Li Zhen, Yu Yirui, Wang Hongwei, Feng Guorui, He Fulian, Wang Dezhang, Zhou Jinhui, Liu Luyan, Han Xinlei Mar 2024

An Experimental Study Of Factors Influencing Gas Seepage In Confined Broken Anthracite, Li Zhen, Yu Yirui, Wang Hongwei, Feng Guorui, He Fulian, Wang Dezhang, Zhou Jinhui, Liu Luyan, Han Xinlei

Coal Geology & Exploration

The void structure evolution of broken coals in a caving zone directly affects the gas seepage characteristics of the zone, further influencing the gas migration and enrichment patterns in abandoned coal mine goaves. With the second generation of compaction-seepage-CT scanning experimental system for broken coals independently designed and developed, this study performed 162 sets of permeability experiments on broken anthracite samples with five particle size ranges under varying gas pressures, axial stresses, and void fractions. Key findings are as follows: (1) When gas migrated in broken anthracite, its pressure and flow rate kept dynamically changing until the adsorption equilibrium was …


Two-Phase Flow Chokeling Results And Control In High-Pressure Gas Wells Producing Water, Liu Xinfu, Liu Chunhua, Li Qingping, Yao Haiyuan, Hao Zhongxian, Liu Yongfei Mar 2024

Two-Phase Flow Chokeling Results And Control In High-Pressure Gas Wells Producing Water, Liu Xinfu, Liu Chunhua, Li Qingping, Yao Haiyuan, Hao Zhongxian, Liu Yongfei

Coal Geology & Exploration

Prediction and control of two-phase flow chokeling in tight gas wellbores are essential for the normal operation and hydrate control of high-pressure gas wells producing water. The thermodynamic differential equations of energy, kinetic energy and temperature and models of chokeling field for two-phase energy, system heat, mass balance and flow were developed under the conditions of isentropic adiabatic, isobaric heat capacity, constant volume heat capacity, and chokeling energy. A methodology on predicting characteristics and control of two-phase flow before and after chokeling was proposed for gas-water two phase flow. It provided a theoretical basis for optimizing the structural parameters of …


Favorable Factors In Methane Production From Residual Coal Post-Biohydrogen Generation, Xia Daping, Liao Jiajia, Chen Zhenhong, Chen Xi, Guo Hongyu, Huang Dan Mar 2024

Favorable Factors In Methane Production From Residual Coal Post-Biohydrogen Generation, Xia Daping, Liao Jiajia, Chen Zhenhong, Chen Xi, Guo Hongyu, Huang Dan

Coal Geology & Exploration

Determining favorable factors in methane production from residual coal post-biohydrogen production holds great theoretical and practical significance for improving the efficiency of methane production in the second stage of coal-based poly-generation. This study focuses on residual coal after hydrogen generation through anaerobic fermentation. Using coal samples from the Baiyinhua open-pit mine in Inner Mongolia as fermentation substrates, this study explored the dynamic trends of both the methane production and structure of the residual coal under different conditions by altering the aeration conditions and hydraulic retention time (HRT). Key findings are as follows: (1) Among the experiment groups with different atmosphere …


Analysis On Working Characteristics Of Cam-Roller Impact Mechanism Of Rotary Percussion Drilling Tool, Sun Yangqing, Yi Xianzhong, Wan Jifang, Ma Jianqi, Wu Jiwei, Yi Jun, Yin Guangpin Mar 2024

Analysis On Working Characteristics Of Cam-Roller Impact Mechanism Of Rotary Percussion Drilling Tool, Sun Yangqing, Yi Xianzhong, Wan Jifang, Ma Jianqi, Wu Jiwei, Yi Jun, Yin Guangpin

Coal Geology & Exploration

Rotary percussion drilling tools can effectively improve their rock breaking efficiency in the deep and hard strata, thus having broad application prospects. The cam-roller is the key mechanism to realize the impact action, but the complex and changeable downhole environment leads to serious damage to the mechanism, which in turn affects the efficiency of rock breaking. Based on the test drilling data of rotary impact drilling tools in several wells, the cam-roller dynamics model was established, the working characteristics under different strokes, speeds and drilling pressures were analyzed by Autodyn (explicit dynamics), and the deformation characteristics of the mechanism were …


Development And Application Of An Automatic Online Testing Instrument For The Funnel Viscosity And Density Of Drilling Fluids, Xie Hui, Zheng Liqun, Liu Fulin, Liang Mengjia, Liu Xuan, Cai Jihua, Yang Xianyu, Hou Jiwu Mar 2024

Development And Application Of An Automatic Online Testing Instrument For The Funnel Viscosity And Density Of Drilling Fluids, Xie Hui, Zheng Liqun, Liu Fulin, Liang Mengjia, Liu Xuan, Cai Jihua, Yang Xianyu, Hou Jiwu

Coal Geology & Exploration

In recent years, the research on the automatic performance testing technology for drilling fluids has achieved significant progress both domestically and internationally. However, automatic drilling fluid testing instruments face challenges, such as high costs, complicated structures, and restricted working environments. Given these challenges, this study developed an automatic online testing instrument for the funnel viscosity and density of drilling fluids. The testing instrument consists of mud pumping, testing, cleaning, and control modules, which are built using a programmable logic controller (PLC), an Internet of things (IoT) module, a pressure sensor, an ultrasonic sensor, a peristaltic mud pump, an electric ball …


Trading Policy, Practice And Prospect On Marine Carbon Sequestration In China, Jingming Dong, Zifei Liu, Limei Chen Mar 2024

Trading Policy, Practice And Prospect On Marine Carbon Sequestration In China, Jingming Dong, Zifei Liu, Limei Chen

Bulletin of Chinese Academy of Sciences (Chinese Version)

Marine carbon sequestration trading is the inherent requirement and effective mechanism for marine eco-civilization development, maritime economic strategy. The research compares and analyzes the policies and practices of China’s marine carbon sequestration trading, and looks forward its future development tendency. It is pointed points out that under the framework of the national Dual Carbon goals, especially in “1+N” policy, the top-level system of China’s marine carbon sequestration trading has initially formed. Many relevant industry standards have been introduced and implemented at the national level. Then at the local level, some regions have introduced and implemented marine carbon sequestration calculation guidelines …


Development Demand, Power Energy Consumption And Green And Low-Carbon Transition For Computing Power In China, Xiaohong Chen, Liaoying Cao, Jiaolong Chen, Jinghui Zhang, Wenzhi Cao, Yangjie Wang Mar 2024

Development Demand, Power Energy Consumption And Green And Low-Carbon Transition For Computing Power In China, Xiaohong Chen, Liaoying Cao, Jiaolong Chen, Jinghui Zhang, Wenzhi Cao, Yangjie Wang

Bulletin of Chinese Academy of Sciences (Chinese Version)

As a critical digital infrastructure, computing power has become the core productivity and a new engine driving economic growth in the digital economy. Nevertheless, the power-hungry nature of computing/data centers, representing the computing infrastructure, consumes a significant amount of electrical energy. Currently, China’s economy is transitioning from high-speed growth to high-quality development. It is imperative to study how to coordinate the development of computing power while ensuring its safety and achieving green and low-carbon goals. Based on an overview of the current status of computing power development, this study predicts the future demand for computing power in China, analyzes the …


Long Term Monitoring And Research On Temperate Glaciers And Related Environments Provide Technological Support For Regional Sustainable Development, Shijin Wang, Shichang Kang, Tuo Chen, Yuanqing He, Meixue Yang, Quanlian Li, Hewen Niu, Tao Pu, Binglin Zhang, Yanjun Che, Wanqin Guo, Xingguo Yan, Xinggang Ma, Rongjun Wang Mar 2024

Long Term Monitoring And Research On Temperate Glaciers And Related Environments Provide Technological Support For Regional Sustainable Development, Shijin Wang, Shichang Kang, Tuo Chen, Yuanqing He, Meixue Yang, Quanlian Li, Hewen Niu, Tao Pu, Binglin Zhang, Yanjun Che, Wanqin Guo, Xingguo Yan, Xinggang Ma, Rongjun Wang

Bulletin of Chinese Academy of Sciences (Chinese Version)

After nearly 20 years of development, the Yulong Snow Mountain National Field Observation and Research Station for Cryosphere and Sustainable Development, Chinese Academy of Sciences has built a field comprehensive observation system and data online visualization platform of temperate glacier and environment integrating observation, research, demonstration, and service. Based on the long-term positioning monitoring of temperate glaciers and the environment, and focusing on key scientific issues related to sustainable development in temperate glacier areas, this study deeply analyzes the mechanism of changes in temperate glaciers, reveals the hydrological, microorganisms, and climatic effects of temperate glacier change, evaluates the effectiveness of …


Yulong Snow Mountain National Field Observation And Research Station For Cryosphere And Sustainable Development Mar 2024

Yulong Snow Mountain National Field Observation And Research Station For Cryosphere And Sustainable Development

Bulletin of Chinese Academy of Sciences (Chinese Version)

No abstract provided.


Challenges To Reindeer, Reciprocity, And Indigenous Sami Sovereignty Amidst The Impact Of Green Energy Developments, Lisa Heikka-Huber Mar 2024

Challenges To Reindeer, Reciprocity, And Indigenous Sami Sovereignty Amidst The Impact Of Green Energy Developments, Lisa Heikka-Huber

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

The Indigenous people of Europe known as the Sami, (also spelled Saami) many of whom live throughout the world, have continued to maintain active nomadic communities today as their ancestors did. A wide spanning region of Northern Europe’s Arctic Zone or Sampi often referred to as Fennoscandia, encompasses four countries, Norway, Sweden, Finland, and Russia’s Kola Peninsula (Roland & Löffler, 2012). The nomadic Sami people follow the migration pathways of their reindeer herds through the wilderness bi-annually. This paper will discuss many perspectives, including the battle Sami people and other Indigenous communities have endured while combating green energy development from …


Difficulties Of Hydrofracturing In Sandstone – Experimental Study, S Vikram, Dheeraj Kumar, Ds Subrahmanyam Mar 2024

Difficulties Of Hydrofracturing In Sandstone – Experimental Study, S Vikram, Dheeraj Kumar, Ds Subrahmanyam

Journal of Sustainable Mining

Hydrofracturing in sandstone is not an easy task. Sandstone is porous; fluid dissipation is common hence unable to obtain breakdown pressures in certain flow rates (0.0000005–0.0001 m3/s). The higher flow rate (0.00025 m3/s) is ascertained to determine the fracturing pressures. Due to this, fracture propagation and delineation are observed [1]. To enhance, an experimental method is adopted by carrying out 6 Hydrofracturing tests in a borehole comprising sandstone. A high flow rate of 0.00025 m3/s and viscosity 0.001 Pascal second is applied. Later, the fracture simulation was run on 12 core samples collected from the same depths in a lab. …


Relocating Lubra Village And Visualizing Himalayan Flood Damages With Remote Sensing, Ronan Wallace, Yungdrung Tsewang Gurung, Ryan Kastner Feb 2024

Relocating Lubra Village And Visualizing Himalayan Flood Damages With Remote Sensing, Ronan Wallace, Yungdrung Tsewang Gurung, Ryan Kastner

Journal of Critical Global Issues

As weather patterns change worldwide, isolated communities impacted by climate change go unnoticed and we need community-driven solutions. In Himalayan Mustang, Nepal, indigenous Lubra Village faces threats of increasing flash flooding. After every flood, residual muddy sediment hardens across the riverbed like concrete, causing the riverbed elevation to rise. As elevation increases, sediment encroaches on Lubra’s agricultural fields and homes, magnifying flood vulnerability. In the last monsoon season alone, the Lubra community witnessed floods swallowing several agricultural fields and damaging two homes. One solution considers relocating the village to a new location entirely. However, relocation poses a challenging task, as …


Environmental Analysis Of Codfish Production And Consumption In Portugal, Ayla Frost, Joana Almeida, Joana Dionisio, Radu Godina, Cátia Magro Feb 2024

Environmental Analysis Of Codfish Production And Consumption In Portugal, Ayla Frost, Joana Almeida, Joana Dionisio, Radu Godina, Cátia Magro

Journal of Critical Global Issues

Codfish, a typical dish consumed frequently in Portugal, is fished in the cold Northern Atlantic waters far from the Portuguese coast. Thus, regional tensions and the environmental impacts of Portuguese codfish importation and production are significant current issues. The present study uses a life cycle assessment methodology to evaluate the array of environmental impacts of the production of 1 kg of codfish, following a cradle to gate approach. The life cycle inventory was grouped into catch and preprocessing, transit, and curing stages. The data collection of products and processes in each stage was based on scientific peer reviewed documents, technical …


Table Of Contents, The Editors Feb 2024

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.


Outcomes And Implications Of Pilot Tests For Deep Coalbed Methane Production On The Eastern Margin Of The Ordos Basin, Nie Zhihong, Xu Fengyin, Shi Xiaosong, Xiong Xianyue, Song Wei, Zhang Lei, Liu Ying, Sun Wei, Feng Yanqing, Liu Shirui, Yan Xia, Sun Xiaoyi, Wu Mansheng Feb 2024

Outcomes And Implications Of Pilot Tests For Deep Coalbed Methane Production On The Eastern Margin Of The Ordos Basin, Nie Zhihong, Xu Fengyin, Shi Xiaosong, Xiong Xianyue, Song Wei, Zhang Lei, Liu Ying, Sun Wei, Feng Yanqing, Liu Shirui, Yan Xia, Sun Xiaoyi, Wu Mansheng

Coal Geology & Exploration

Breakthroughs in the exploration and production of deep coalbed methane (CBM) in the Daning-Jixian block on the eastern margin of the Ordos Basin exert a profound influence on the CBM industry, arousing extensive concern and follow-up. Although previous studies delved into the theoretical and technical challenges and corresponding solutions of deep CBM exploration and production, there is a lack a systematic summary of pilot tests for typical gas field exploitation. Through an in-depth dissection of the geological characteristics and challenges of cost-effective production of deep CBM, this study summarized the advances and outcomes of the pilot test projects in the …


Exploration And Exploitation Of Deep Coalbed Methane In The Baijiahai Uplift, Junggar Basin: Progress And Its Implications, Lan Hao, Yang Zhaobiao, Chou Peng, Wang Bin, Liu Changqing, Liang Yuhui, Wang Yuqiang Feb 2024

Exploration And Exploitation Of Deep Coalbed Methane In The Baijiahai Uplift, Junggar Basin: Progress And Its Implications, Lan Hao, Yang Zhaobiao, Chou Peng, Wang Bin, Liu Changqing, Liang Yuhui, Wang Yuqiang

Coal Geology & Exploration

The Jurassic coals in the Baijiahai uplift, with breakthroughs made in the deep coalbed methane (CBM) production of vertical wells in the early stage in China, serve as an important exploration target of the Junggar Basin. Their coal reservoirs feature an ultra-low ash content, a low moisture content, medium-to-high volatility, and favorable porosity and permeability systems. With gas accumulation modes, namely, the paleo-source and young-reservoir made and the self-source and self-reservoir mode, the coal seams enjoy favorable gas-bearing properties, such as a high gas content, a high proportion of free gas, and high gas saturation, which establish them as high-quality …


Deep Coalbed Methane Production Technology For The Eastern Margin Of The Ordos Basin: Advances And Their Implications, Zeng Wenting, Xu Fengyin, Zhang Lei, Sun Weiwei, Wang Qian, Liu Yinhua, Yu Lizhu, Ji Liang, Zeng Quanshu, Zhang Kang Feb 2024

Deep Coalbed Methane Production Technology For The Eastern Margin Of The Ordos Basin: Advances And Their Implications, Zeng Wenting, Xu Fengyin, Zhang Lei, Sun Weiwei, Wang Qian, Liu Yinhua, Yu Lizhu, Ji Liang, Zeng Quanshu, Zhang Kang

Coal Geology & Exploration

Contrasting with shallow to moderately deep coalbed methane (CBM) reservoirs, deep CBM reservoirs exhibit favorable coal structures, high formation pressure, high free gas ratios, and high contents of total dissolved solids (TDS) and CO2. Extensive fracturing allows for CBM flowing at the initial stage, while the production parameters vary significantly throughout the CBM production. This requires wide technological boundaries of the main production technologies. Compared to shale gas and tight gas, deep CBM manifests different production mechanisms and relatively low free gas ratios, which lead to short flowing cycles of CBM. This necessitates timely water withdrawal for CBM …


Differences In Geological Conditions Of Deep And Shallow Coalbed Methane And Their Formation Mechanisms, Xu Hao, Tang Dazhen, Tao Shu, Li Song, Tang Shuling, Chen Shida, Zong Peng, Dong Yu Feb 2024

Differences In Geological Conditions Of Deep And Shallow Coalbed Methane And Their Formation Mechanisms, Xu Hao, Tang Dazhen, Tao Shu, Li Song, Tang Shuling, Chen Shida, Zong Peng, Dong Yu

Coal Geology & Exploration

Deep coalbed methane (CBM) boasts abundant resources and great potential for exploitation. However, there is a lack of in-depth studies on the internal connections between deep and shallow CBM. This study investigated the Upper Paleozoic coalbed in the Ordos Basin. From the perspective of coalbed formation and evolution, it obtained three burial depth evolution modes of coalbed through summaries: both the maximum and present burial depths exceeding 2000 m, the maximum burial depth over 2000 m while the present burial depth less than 2000 m, and both the maximum and present burial depths less than 2000 m. This study systematically …


Occurrence Mechanism, Environment And Dynamic Evolution Of Gas And Water In Deep Coal Seams, Li Yong, Xu Lifu, Liu Yu, Wang Ziwei, Gao Shuang, Ren Ci Feb 2024

Occurrence Mechanism, Environment And Dynamic Evolution Of Gas And Water In Deep Coal Seams, Li Yong, Xu Lifu, Liu Yu, Wang Ziwei, Gao Shuang, Ren Ci

Coal Geology & Exploration

Accurately understanding of the occurrence states, relative content, and distribution characteristics of gas - water under deep conditions has important guiding significance for efficient exploration and development of coalbed methane (CBM). Based on the theoretical model, molecular simulation and systematic analysis of gas-water, the occurrence states of gas-water in coal seam is clarified, and the boundary and dynamic evolution process of gas-water dynamic migration and accumulation are revealed. Considering the coal - water interface interaction, the mobility and occurrence states of water, the coalbed water can be divided into movable water (gravity water and capillary water), bound water (adsorbed water, …


Effects Of Depth On Gas-Bearing Properties Of Coal Reservoirs And Their Coupling Relationships With Coalbed Methane Accumulation, Chen Shida, Hou Wei, Tang Dazhen, Li Xiang, Xu Hao, Tao Shu, Li Song, Tang Shuling Feb 2024

Effects Of Depth On Gas-Bearing Properties Of Coal Reservoirs And Their Coupling Relationships With Coalbed Methane Accumulation, Chen Shida, Hou Wei, Tang Dazhen, Li Xiang, Xu Hao, Tao Shu, Li Song, Tang Shuling

Coal Geology & Exploration

Burial depth serves as a comprehensive factor influencing coalbed methane (CBM) accumulation. Understanding the effects of depth on gas-bearing properties is critical for ascertaining the occurrence states and accumulation mechanisms of deep/shallow CBM. Based on the present situation of CBM exploration and the dissection of data from CBM exploration wells on the eastern margin of the Ordos Basin, this study explored the effects of burial depth on the gas content, saturated adsorbed gas capacity, and gas saturation of coal seams, as well as their coupling relationship with accumulation processes, using conventional and unconventional petroleum accumulation. The results indicate that CBM …


Origin And Accumulation Mechanisms Of Coalbed Methane In Low-Rank Coals In Gas-Rich Sags In The Erlian Basin, Lin Haitao, Li Ling, Tang Shuling, Tian Wenguang, Li Jie, Meng Qin Feb 2024

Origin And Accumulation Mechanisms Of Coalbed Methane In Low-Rank Coals In Gas-Rich Sags In The Erlian Basin, Lin Haitao, Li Ling, Tang Shuling, Tian Wenguang, Li Jie, Meng Qin

Coal Geology & Exploration

Inner Mongolia boasts abundant coalbed methane (CBM) resources in low-rank coals. Investigating the origin and accumulation mechanisms of CBM is crucial for the siting and assessment of these CBM resources. This study examined the CBM in low-rank coals in major gas-rich sags of the Erlian Basin through various experiments, including tests of the composition and carbon/hydrogen isotopes of CBM, as well as tests of the water quality, hydrogen/oxygen isotopes, and radioisotopes (3H and 14C) of coal seam water. By analyzing the geochemical characteristics of both CBM and coal seam water, this study revealed the origin, sources, and …


Deep Coalbed Methane Resources In The Shenmu-Jiaxian Block, Ordos Basin, China: Geological Characteristics And Potential For Exploration And Exploitation, Li Guoyong, Yao Yanbin, Wang Hui, Meng Lingjian, Li Peijie, Zhang Yongchao, Wang Jianwei, Ma Limin Feb 2024

Deep Coalbed Methane Resources In The Shenmu-Jiaxian Block, Ordos Basin, China: Geological Characteristics And Potential For Exploration And Exploitation, Li Guoyong, Yao Yanbin, Wang Hui, Meng Lingjian, Li Peijie, Zhang Yongchao, Wang Jianwei, Ma Limin

Coal Geology & Exploration

China boasts abundant coalbed methane (CBM) resources in deep layers (burial depths: greater than 2000 m), with considerable potential for CBM exploration and development. Compared to medium and shallow CBM, deep CBM differs significantly in enrichment and accumulation patterns and exploitation means. Therefore, there is an urgent need to dissect key CBM blocks. The Shenmu-Jiaxian block, situated in the northeastern Ordos Basin, is currently in the early stages of deep CBM exploration, with enrichment characteristics and exploration potential remaining undefined. Based on recently obtained seismic data, logging data from over 300 wells, and analytical results from four cored wells, this …


Enrichment And Accumulation Patterns And Favorable Area Evaluation Of Deep Coalbed Methane In The Fugu Area, Ordos Basin, Guo Guangshan, Xu Fengyin, Liu Lifang, Cai Yidong, Qin Wei, Chen Zhaohui, Deng Jimei, Li Zhuolun Feb 2024

Enrichment And Accumulation Patterns And Favorable Area Evaluation Of Deep Coalbed Methane In The Fugu Area, Ordos Basin, Guo Guangshan, Xu Fengyin, Liu Lifang, Cai Yidong, Qin Wei, Chen Zhaohui, Deng Jimei, Li Zhuolun

Coal Geology & Exploration

The Shenfu block on the eastern margin of the Ordos Basin is a typical deep coalbed methane (CBM) field with abundant resources and considerable potential for exploration and exploitation. In October 2023, the large-scale Shenfu deep CBM field successfully reported proven geological reserves exceeding 110 billion m3. The Fugu area, located in the central part of the Shenfu block, is the earliest experimental area for deep CBM production. However, there is a lack of a clear understanding of CBM enrichment and accumulation patterns, as well as the potential for exploration and development, of this area. By comprehensively utilizing …


Potential For The Production Of Deep To Ultradeep Coalbed Methane Resources In The Upper Permian Longtan Formation, Sichuan Basin, Ming Ying, Sun Haofei, Tang Dazhen, Xu Liang, Zhang Benjian, Chen Xiao, Xu Chang, Wang Jiaxian, Chen Shida Feb 2024

Potential For The Production Of Deep To Ultradeep Coalbed Methane Resources In The Upper Permian Longtan Formation, Sichuan Basin, Ming Ying, Sun Haofei, Tang Dazhen, Xu Liang, Zhang Benjian, Chen Xiao, Xu Chang, Wang Jiaxian, Chen Shida

Coal Geology & Exploration

Breakthroughs have been achieved in the high-yield gas flow of coalbed methane (CBM) wells with burial depths ranging from 1000 to 2500 m in the Cainan area of the Junggar Basin and the Daning-Jixian and southern Yanchuan blocks on the eastern margin of the Ordos Basin, signifying the enormous potential for the production of deep CBM. In the Sichuan Basin, the thin to moderately thick coal seam groups (7‒15 layers) in the Upper Permian Longtan Formation primarily exhibit burial depths ranging between 2000 and 4500 m. In the central Sichuan Basin, characterized by north-dipping monoclines and local low-amplitude uplifts, deep …


Geological Characteristics And Favorable Area Evaluation Of Deep Coalbed Methane In Wangfu Fault Depression, Southern Songliao Basin, Shen Xia, Gong Haitao, Shao Mingli, Yang Minfang, Huo Wanguo Feb 2024

Geological Characteristics And Favorable Area Evaluation Of Deep Coalbed Methane In Wangfu Fault Depression, Southern Songliao Basin, Shen Xia, Gong Haitao, Shao Mingli, Yang Minfang, Huo Wanguo

Coal Geology & Exploration

The Wangfu fault depression in the southern Songliao Basin is rich in coalbed methane (CBM) resources. However, CBM exploration in this area has been restricted by the low-level exploration of deep CBM and a lack of systematic studies on the geological characteristics of CBM, primary factors controlling CBM enrichment and accumulation, and the selection of favorable targets. Therefore, based on the systematical analysis of the geological characteristics of coal-bearing strata, this study identified the major factors controlling deep CBM accumulation, established the index system for favorable area selection, and predicted the favorable areas of CBM enrichment. The results show that: …


Moderately Deep Coalbed Methane Reservoirs In The Southern Qinshui Basin: Characteristics And Technical Strategies For Exploitation, Zhang Cong, Li Mengxi, Hu Qiujia, Jia Huimin, Li Kexin, Wang Qi, Yang Ruiqiang Feb 2024

Moderately Deep Coalbed Methane Reservoirs In The Southern Qinshui Basin: Characteristics And Technical Strategies For Exploitation, Zhang Cong, Li Mengxi, Hu Qiujia, Jia Huimin, Li Kexin, Wang Qi, Yang Ruiqiang

Coal Geology & Exploration

This study investigated the northern Zhengzhuang-western Qinnan block for the purpose of achieving effective exploitation of moderately deep coalbed methane (CBM) reservoirs in the southern Qinshui Basin. Based on results from the analyses and tests of parametric wells, including core analysis and tests, injection/falloff tests, and in situ stress cyclic tests, as well as a large amount of dynamic and static data, this study expounded on the characteristics of moderately deep CBM reservoirs in the study area by comparison with shallow counterparts. Then, it explored the technical improvements in fracturing through vertical wells and staged fracturing through horizontal wells for …


A Calculation Model Of Free Gas Saturation In Deep Coalbed Methane Reservoirs And Its Application, Shi Juntai, Cao Jingtian, Xu Fengyin, Xiong Xianyue, Huang Hongxing, Sun Zheng, Jia Yanran, Ma Shurui, Zheng Haohang, Deng Ting, Li Jing, Li Xiangfang Feb 2024

A Calculation Model Of Free Gas Saturation In Deep Coalbed Methane Reservoirs And Its Application, Shi Juntai, Cao Jingtian, Xu Fengyin, Xiong Xianyue, Huang Hongxing, Sun Zheng, Jia Yanran, Ma Shurui, Zheng Haohang, Deng Ting, Li Jing, Li Xiangfang

Coal Geology & Exploration

In recent years, breakthroughs have been achieved in the exploration of deep coalbed methane (CBM) in China based on fine-scale geological research and techniques such as multistage hydraulic fracturing using proppants in a horizontal well. As a result, some wells yielded daily gas production of up to 100000 m3, inspiring confidence again in the CBM industry. However, since deep coal reservoirs occur in a complex geological environment characterized by high in-situ stress, high geotemperature, high pore pressure, and low permeability, there is an urgent need to reveal the typical parameters of coal reservoirs at different depths and the …


Multi-Round Diverting Fracturing Technology And Its Application In Deep Coalbed Methane In The Daning-Jixian Block, Xiong Xianyue, Zhen Huaibin, Li Shuguang, Wang Hongna, Zhang Lei, Song Wei, Lin Hai, Xu Fengyin, Li Zhongbai, Zhu Weiping, Wang Chengwang, Chen Gaojie Feb 2024

Multi-Round Diverting Fracturing Technology And Its Application In Deep Coalbed Methane In The Daning-Jixian Block, Xiong Xianyue, Zhen Huaibin, Li Shuguang, Wang Hongna, Zhang Lei, Song Wei, Lin Hai, Xu Fengyin, Li Zhongbai, Zhu Weiping, Wang Chengwang, Chen Gaojie

Coal Geology & Exploration

The Daning-Jixian block on the eastern margin of the Ordos Basin exhibits high-abundance deep coalbed methane (CBM) resources, well-developed natural fractures of coal reservoirs, well-developed cleats and fractures in coals themselves, coals with excellent structures and high mechanical strength, and strong sealing ability of coal roofs and floors. All these create favorable conditions for the formation of a large-scale fracture network through volume fracturing. The ultra-large-scale fracturing process has contributed to a major breakthrough in the single-well output of deep CBM. However, the tracer monitoring results show that various fracturing stages of horizontal wells exhibited different contribution rates to gas …


Mechanisms And Technological Parameter Optimization Of Near-Wellbore Laser Thermal Fracturing For Deep Coal Seams, Zhao Haifeng, Yang Ziyi, Liang Wei, Zhong Junbing Feb 2024

Mechanisms And Technological Parameter Optimization Of Near-Wellbore Laser Thermal Fracturing For Deep Coal Seams, Zhao Haifeng, Yang Ziyi, Liang Wei, Zhong Junbing

Coal Geology & Exploration

China boasts abundant deep coalbed methane (CBM) resources, which play a significant role in further CBM production. However, deep coal seams exhibit low porosities and ultra-low permeabilities due to intricate geological conditions. In the drilling process, drilling fluids enter the reservoirs, prone to cause near-wellbore contamination. Although conventional hydraulic fracturing technology tends to create fractures in the direction of the maximum horizontal principal stress, it is challenging for this technology to achieve blockage removing throughout the whole borehole. Laser thermal fracturing technology can break rocks in a short time. Furthermore, it allows for the laser irradiation angle to change freely …


Exploring The Principle And Method For Commingled Production Of Coal-Measure Gas Through Layered Pressure Relief In Surface Wells, Li Rui, Jin Lihong, Xia Binwei, Ge Zhaolong Feb 2024

Exploring The Principle And Method For Commingled Production Of Coal-Measure Gas Through Layered Pressure Relief In Surface Wells, Li Rui, Jin Lihong, Xia Binwei, Ge Zhaolong

Coal Geology & Exploration

This study aims to gain an in-depth understanding of factors restricting the commingled production of coal-measure gas and boost the contributions of various pay zones to gas production. To this end, it analyzed the essential factors of the dynamic, channel, and gas source conditions in the commingled production. The dynamic conditions for the commingled exploitation of multiple reservoirs can be met by (1) enhancing the flow conductivity of reservoirs by altering the crustal stress state and (2) changing reservoir fluid pressure by layers. Following this principle, this study proposed a method for the commingled production of coal-measure gas through layered …