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Full-Text Articles in Mining Engineering
Variable-Temperature And Variable-Pressure Adsorption Characteristics Of Deep Coalbed Methane And Their Implications, Jiang Wenping, Sun Siqing, Jin Xianglan, Tian Bofan, Tian Xinjuan
Variable-Temperature And Variable-Pressure Adsorption Characteristics Of Deep Coalbed Methane And Their Implications, Jiang Wenping, Sun Siqing, Jin Xianglan, Tian Bofan, Tian Xinjuan
Coal Geology & Exploration
Background Investigating the adsorption characteristics of coalbed methane (CBM) helps bridge key geological information concerning deep CBM, including occurrence state, free gas proportion, and gas-bearing properties, with the gas production potential and commercial exploitation of CBM wells. Such investigation represents a key component of the evaluation, exploration, and exploitation of CBM reservoirs. Methods Using deep coal samples collected from three representative regions, this study designed high-temperature and high-pressure methane isothermal adsorption experiments, together with variable-temperature and variable-pressure methane adsorption experiments, using nuclear magnetic resonance (NMR). The adsorption characteristics of the coal samples derived using the different experimental methods were subsequently …
Occurrence Pattern Of Adsorbed And Free Gas In Deep Coal Seams Under The Control Of Pore Structure: A Case Study Of The No. 8 Coal Seam In The Daning-Jixian Block Along The Eastern Margin Of The Ordos Basin, Bian Liheng, Shen Jian, Shi Rui, Zhang Wei, Ma Zhuang, Liang Xuemin, Dong Jiying, Zhu Peipei, Ma Tianyu
Occurrence Pattern Of Adsorbed And Free Gas In Deep Coal Seams Under The Control Of Pore Structure: A Case Study Of The No. 8 Coal Seam In The Daning-Jixian Block Along The Eastern Margin Of The Ordos Basin, Bian Liheng, Shen Jian, Shi Rui, Zhang Wei, Ma Zhuang, Liang Xuemin, Dong Jiying, Zhu Peipei, Ma Tianyu
Coal Geology & Exploration
Background Deep coalbed methane (CBM) holds an important strategic position in China's unconventional natural gas system. However, concerning deep CBM occurrence, there remains a lack of systematic quantitative understanding of the underlying mechanisms and the controlling effects of pore structure. Methods This study investigated high-rank coal samples collected at a burial depth of approximately 2000 m from the No. 8 coal seam in the Daning-Jixian block along the eastern margin of the Ordos Basin. Using multiscale pore characterization techniques, including low-temperature liquid nitrogen adsorption, high-pressure mercury injection, and low-temperature CO2 adsorption, the full-scale pore size distribution of the coal …
Controlling Effects Of Ash Yield On The Adsorption-Desorption Behavior And Production Potential Of Methane In Deep Coal Reservoirs, Huang Daojun, Liu Xinshe, Chen Shida, Sun Wen, Jiao Pengshuai, Wang Huaichang
Controlling Effects Of Ash Yield On The Adsorption-Desorption Behavior And Production Potential Of Methane In Deep Coal Reservoirs, Huang Daojun, Liu Xinshe, Chen Shida, Sun Wen, Jiao Pengshuai, Wang Huaichang
Coal Geology & Exploration
Objective The lithotype and quality characteristics of coals significantly affect the reservoir permeability and production potential of coalbed methane (CBM). However, there remains a lack of clear understanding of the controlling effects of ash yield on the gas-bearing properties and methane adsorption-desorption behavior of coal seams under comparable thermal maturity. Focusing on coal samples obtained through continuous sealed coring from the No. 8 coal seam in well M172 in the east-central part of the Ordos Basin, this study aims to clarify the impacts of ash yield on the pore structure, adsorption capacity, desorption process, and resource recoverability. This effort is …
An Improved Brittleness Characterization Method For Deep Coalbed Methane Reservoirs And Its Application To Well Logs, Huang An’Er, Gong Fei, Peng Suping, Zou Guangui, Zhang Zhaoji, Wu Yiquan, Rong Zhihong, Li Qingrun
An Improved Brittleness Characterization Method For Deep Coalbed Methane Reservoirs And Its Application To Well Logs, Huang An’Er, Gong Fei, Peng Suping, Zou Guangui, Zhang Zhaoji, Wu Yiquan, Rong Zhihong, Li Qingrun
Coal Geology & Exploration
Background Deep coalbed methane (CBM) reservoirs are characterized by high pressure, low porosity, and low permeability. Therefore, large-scale volume fracturing is required for their commercial development. As an important engineering sweet spot parameter for selecting optimal fracturing targets, the brittleness index can reflect the difficulty in generating complex fracture networks during fracturing. However, existing brittleness characterization methods are largely applicable to strata with high brittle mineral content, such as shales and sandstones, while methods for characterizing the brittleness of deep CBM reservoirs with high organic matter content and low brittle mineral content are lacking. Methods Rock physics experiments on 20 …
A Fault Identification Method For Deep Coalbed Methane Reservoirs Based On An Improved Transunet, Gao Congshun, Wu Haibo, Liu Lei, Wang Zijian, Huang Xuanyu, Jia Lilan, Xu Aiguo
A Fault Identification Method For Deep Coalbed Methane Reservoirs Based On An Improved Transunet, Gao Congshun, Wu Haibo, Liu Lei, Wang Zijian, Huang Xuanyu, Jia Lilan, Xu Aiguo
Coal Geology & Exploration
Objective Small-scale faults in deep coalbed methane (CBM) reservoirs significantly affect CBM enrichment and the deployment of development wells. However, deep seismic data tend to suffer from low signal-to-noise ratios (SNRs) and poor continuity of reflection events, while conventional methods are likely to miss small-scale faults. To address these limitations, this study proposes a fault identification method based on an improved TransUNet. Methods The proposed method is developed based on the R50-ViT-B_16 TransUNet architecture. A coordinate attention (CA) module is introduced before the skip connections enter the decoder to enhance the feature representation of the locations and directional continuity of …
Petrophysical Model-Driven Seismic Inversion For Physical Property Parameters Of Deep Coalbed Methane Reservoirs, Chen Yang, Guo Qiang, Ba Jing
Petrophysical Model-Driven Seismic Inversion For Physical Property Parameters Of Deep Coalbed Methane Reservoirs, Chen Yang, Guo Qiang, Ba Jing
Coal Geology & Exploration
Objective Deep coalbed methane (CBM) reservoirs typically exhibit complex pore-fracture structures, as well as strong nonlinear and non-unique corresponding relationships between elastic and physical property parameters. In this context, this study develops a seismic petrophysical inversion method that accounts for pore structure variations. Methods This study investigated deep CBM reservoirs along the eastern margin of the Ordos Basin. First, a petrophysical model based on variable pore aspect ratios was established, and the corresponding linearized forward operator was derived. Then, the pore aspect ratios were estimated using near-borehole log data. Meanwhile, the multimodal prior distributions of reservoir physical property parameters were …
Intelligent Identification Of Deep Coal Macrolithotypes Based On Weighted Ensemble In Machine Learning: A Case Study Of The Shenmu Area, Ordos Basin, Yao Yuhao, Yang Zhaobiao, Huang Daojun, Wang Jianan, Dong Guodong, Chen Yilin, He Jinxian, Zhang Shang
Intelligent Identification Of Deep Coal Macrolithotypes Based On Weighted Ensemble In Machine Learning: A Case Study Of The Shenmu Area, Ordos Basin, Yao Yuhao, Yang Zhaobiao, Huang Daojun, Wang Jianan, Dong Guodong, Chen Yilin, He Jinxian, Zhang Shang
Coal Geology & Exploration
Objective Coal macrolithotype represents a key geological property in the exploration and recovery of deep coalbed methane (CBM) resources, and its accurate identification is of great significance for selecting the optimal geological and engineering sweet-spot intervals. However, conventional coal macrolithotype identification relies heavily on core observation, suffering from prohibitively high costs since core data are extremely valuable and thus feature a small sample size. Meanwhile, conventional log-based threshold methods face challenges in effectively characterizing the complex boundaries between coal macrolithotypes.Methods This study investigated the No. 8 coal seam of the Benxi Formation, Shenmu area, eastern Ordos Basin. Based on …
Technology Roadmap And Countermeasures For Lean Development Of Low-Grade Deep Coalbed Methane: A Case Study Of The Linxing-Shenfu Block, Ordos Basin, Wu Guang’Ai, Xing Xuesong, Wu Jianshu, Zhu Ying, Zi Jingyu, Wang Zhi, Hou Yanan, Cheng Yuxiong, Liu Xin
Technology Roadmap And Countermeasures For Lean Development Of Low-Grade Deep Coalbed Methane: A Case Study Of The Linxing-Shenfu Block, Ordos Basin, Wu Guang’Ai, Xing Xuesong, Wu Jianshu, Zhu Ying, Zi Jingyu, Wang Zhi, Hou Yanan, Cheng Yuxiong, Liu Xin
Coal Geology & Exploration
Background Accelerating deep coalbed methane (CBM) exploitation is a strategic initiative for the energy security and energy mix optimization of China. The Linxing-Shenfu block in the Ordos Basin holds considerable resource potential of deep CBM. However, this block exhibits typical geological characteristics of low-grade deep CBM, including the complete absence of free gas, gas content < 14 m3/t, reservoir permeability < 0.1 × 10−3 μm2, and strong heterogeneity. These characteristics lead to low efficiency of conventional development models. Therefore, there is an urgent need to develop an efficient technical system tailored to these characteristics. Method To address the core contradiction between reservoir …
Numerical Simulation Of Stress Shadow Effect And Cluster Spacing Optimization For Multi-Cluster Fracturing In Deep Coalbed Methane Horizontal Wells, Guo Guangshan, Deng Zhiyu, Sun Le, Pu Yifan, Wu Jian, Tao Shu, Chen Shaojuan, Chen Shida
Numerical Simulation Of Stress Shadow Effect And Cluster Spacing Optimization For Multi-Cluster Fracturing In Deep Coalbed Methane Horizontal Wells, Guo Guangshan, Deng Zhiyu, Sun Le, Pu Yifan, Wu Jian, Tao Shu, Chen Shaojuan, Chen Shida
Coal Geology & Exploration
Purpose Multi-stage, multi-cluster fracturing in horizontal wells represents a key technique for deep coalbed methane (CBM) recovery and the sustainable development of the industry. However, during multi-cluster fracturing in deep CBM horizontal wells, the stress shadow effect tends to induce non-uniform fracture propagation and a limited stimulated reservoir volume (SRV). Methods To address these challenges. this study established a two-dimensional (2D) numerical model for multi-cluster hydraulic fracturing in horizontal wells using the finite element method. Then, it systematically analyzed the impacts of in situ stress and cluster spacing on both the stress shadow effect and the competitive propagation of hydraulic …
Numerical Simulation And Process Optimization Of Multi-Round Fracturing In Deep Coalbed Methane Wells In The Linxing-Shenfu Block, Li Yu, Zhang Liang, Li Yunyun, An Qi, Feng Xuesong, Lan Tian, Yu Ji, Liu Xin
Numerical Simulation And Process Optimization Of Multi-Round Fracturing In Deep Coalbed Methane Wells In The Linxing-Shenfu Block, Li Yu, Zhang Liang, Li Yunyun, An Qi, Feng Xuesong, Lan Tian, Yu Ji, Liu Xin
Coal Geology & Exploration
Objective Deep coalbed methane (CBM) holds considerable resource potential. However, deep CBM reservoirs exhibit high in-situ stresses, while deep coals feature strong plasticity and heterogeneity. These characteristics render it challenging to generate complex fracture networks through conventional fracturing, thus restricting the large-scale commercial development of deep CBM resources. Multi-round fracturing enables fracture initiation, propagation, and propping through sequential cycles of fracturing fluid injection, pump shut-in, and injection. By constantly changing near-wellbore stress fields, this technique facilitates the formation of complex fracture networks and ensures uniform reservoir stimulation. Method Using the finite-discrete element method (FDEM), this study established a numerical model …
Research And Practice Of Four-Dimensional In-Situ Stress Fields For Deep Coalbed Methane Production: A Case Study Of The Daning-Jixian Block, Ordos Basin, Wang Chengwang, Chen Yiyu, Gao Deli, Zhao Haifeng, Chen Gaojie
Research And Practice Of Four-Dimensional In-Situ Stress Fields For Deep Coalbed Methane Production: A Case Study Of The Daning-Jixian Block, Ordos Basin, Wang Chengwang, Chen Yiyu, Gao Deli, Zhao Haifeng, Chen Gaojie
Coal Geology & Exploration
Background Deep coalbed methane (CBM) reservoirs are characterized by well-developed microstructures and natural fractures, along with highly heterogeneous rock mechanical properties and in-situ stress field distribution. The CBM production of the reservoirs tends to cause constantly evolving formation pressure and in-situ stress within the control ranges of CBM wells, further enhancing the complexity of stress distribution. Additionally, severe fracturing channeling can be observed between new and old wells. This phenomenon is primarily triggered by in-situ stress variations induced by large-scale fracturing and CBM production. Therefore, accurately assessing the dynamic evolutionary patterns of in-situ stresses in reservoirs after fracturing and during …
Heterogeneity And Its Controlling Effect On Coalbed Methane Productivity For Deep Coal Reservoirs In The Northern Part Of The Eastern Margin Of The Ordos Basin, Xi Zhaodong, Tang Shuheng, Wu Jian, Zhang Songhang, Zhao Hang, Chen Jiang, Li Yanfei
Heterogeneity And Its Controlling Effect On Coalbed Methane Productivity For Deep Coal Reservoirs In The Northern Part Of The Eastern Margin Of The Ordos Basin, Xi Zhaodong, Tang Shuheng, Wu Jian, Zhang Songhang, Zhao Hang, Chen Jiang, Li Yanfei
Coal Geology & Exploration
Objective With the continuous advancement in the exploration and exploitation of coalbed methane (CBM), the focus of research and practices is gradually shifting from shallow to deep parts. Deep CBM, an important unconventional natural gas resource, has become a strategic replacement to ensure energy security and prompt industrial development in China. However, deep coal reservoirs exhibit strong heterogeneities, posing a core geological challenge to their efficient exploration and development. Methods This study investigated the deep No. 8 coal seam in the northern part of the eastern margin of the Ordos Basin. By integrating multiple technical methods, including geostatistics, spatial interpolation, …
Advances And Prospects Of Design Optimization Technologies For Differential Development With Three-Dimensional Well Patterns For Deep Coalbed Methane Reservoirs: A Case Study Of The No. 8 Coal Seam In The Ordos Basin, Yan Xia, Fang Jianlong, Mou Chun, Meng Peilong, Wang Yuan, Yu Xiang, Fei Shixiang, Feng Yanqing, Zhao Longmei, Li Meng, Cui Yuehua, Chi Runlong, Yang Qing, Huang Li, Zheng Xiaopeng, Yin Zesong, Wang Congcong, Ma Limin, Zhang Shuang, Liu Shirui, Zhang Yang, Guo Jiali
Advances And Prospects Of Design Optimization Technologies For Differential Development With Three-Dimensional Well Patterns For Deep Coalbed Methane Reservoirs: A Case Study Of The No. 8 Coal Seam In The Ordos Basin, Yan Xia, Fang Jianlong, Mou Chun, Meng Peilong, Wang Yuan, Yu Xiang, Fei Shixiang, Feng Yanqing, Zhao Longmei, Li Meng, Cui Yuehua, Chi Runlong, Yang Qing, Huang Li, Zheng Xiaopeng, Yin Zesong, Wang Congcong, Ma Limin, Zhang Shuang, Liu Shirui, Zhang Yang, Guo Jiali
Coal Geology & Exploration
Objective Design optimization for gas reservoir development serves as a key approach to the efficient exploitation, enhanced primary recovery, and elevated efficiency with reduced costs of deep coalbed methane (CBM). Methods In this study, the most extensively developed Ordos Basin in China was investigated as an example to explore the significant heterogeneity of the geological conditions of deep coal seams. Based on a fine-scale geological investigation of over 3 000 wells across the basin, this study systematically revealed the heterogeneity of the key parameters of deep coal reservoirs, including reservoir distribution, reservoir-cap rock assemblages, coal seam structure, and gas-bearing properties. …
Key Techniques For Volume Fracturing Of Deep Coalbed Methane Reservoirs And Their Applications: A Case Study Of The Daning-Jixian Block, Li Shuguang, Xiong Xianyue, Zhen Huaibin, Bai Kunsen, Ji Yuan, Yuan Pu, Li Zhongbai, Zhu Weiping
Key Techniques For Volume Fracturing Of Deep Coalbed Methane Reservoirs And Their Applications: A Case Study Of The Daning-Jixian Block, Li Shuguang, Xiong Xianyue, Zhen Huaibin, Bai Kunsen, Ji Yuan, Yuan Pu, Li Zhongbai, Zhu Weiping
Coal Geology & Exploration
Background Deep coalbed methane (CBM) reservoirs generally exhibit ultra-low porosity and permeability, high stress, predominance of nanopores, and complex fracture propagation. These characteristics complicate reservoir stimulation, thereby restricting the enhancement in single-well productivity and commercial exploitation. Since 2019, technologies for deep CBM recovery have evolved from volumetric acid fracturing, which highlights the enhancement of matrix permeability, into large-scale volume fracturing focusing on the elevation of both the fracture network scale and proppant efficiency. In 2023, ultra-large-scale volume fracturing aimed at maximizing estimated ultimate recovery (EUR) was further developed. However, the implementation of this novel technique poses challenges such as a …
Damage Evolution Of Coal Reservoirs Under Cyclic Disturbances And Optimization Suggestions For Deep Reservoir Stimulation, Chen Shida, Pu Yifan, Zhao Longmei, Li Xiang, Huang Li, Tang Dazhen, Zhang Yafei, Li Song, Tao Shu
Damage Evolution Of Coal Reservoirs Under Cyclic Disturbances And Optimization Suggestions For Deep Reservoir Stimulation, Chen Shida, Pu Yifan, Zhao Longmei, Li Xiang, Huang Li, Tang Dazhen, Zhang Yafei, Li Song, Tao Shu
Coal Geology & Exploration
Objectives and Methods During volume fracturing or multi-round hydraulic fracturing of deep coal reservoirs, pressure fluctuations induced by the propagation of fracture tips and fluid accumulation within fractures cause cyclic perturbations to surrounding rocks. To clarify both the mechanical responses of coals and the mechanisms behind fracture evolution within coal reservoirs under such cyclic perturbations, this study conducted triaxial cyclic loading-unloading tests on high-rank coals under varying confining pressures, stress amplitudes, and loading modes. In combination with field engineering data, this study proposed strategies for optimizing deep coal reservoir stimulation. Results and Conclusions The stress-strain curves of coals under cyclic …
Strategic Layout And Optimization Paths Of The Standard System For The Exploration And Exploitation Of Deep Coalbed Methane, Chen Xinjun, Liu Zengqin, Shen Baojian, Zhao Shihu, Ye Jincheng, Zhang Jiaqi, Wang Tianyun
Strategic Layout And Optimization Paths Of The Standard System For The Exploration And Exploitation Of Deep Coalbed Methane, Chen Xinjun, Liu Zengqin, Shen Baojian, Zhao Shihu, Ye Jincheng, Zhang Jiaqi, Wang Tianyun
Coal Geology & Exploration
Objective In China, the deep coalbed methane (CBM) industry has emerged as a key sector for the reserve growth and production addition of natural gas. However, the current CBM technical standard system, which was developed based on shallow CBM practices, is incompatible with the demands for the exploration and development of deep CBM. To address this challenge, this study proposes the optimization paths of the current standard system, aiming to provide standardization support for large-scale exploitation of deep CBM.Methods Deep CBM reservoirs exhibit complex geological conditions of high temperature, pressure, and in-situ stress, as well as the CBM occurrence …
Coupling Mechanisms Of Fracture Propagation And Proppant Transport Indeep Coalbed Methane Reservoirs, Guo Xiaodong, Zhang Shicheng, Zhang Jingchen, Zhou Changjing, Zhang Chengsheng, Qiu Shixin, Xi Xiangrui
Coupling Mechanisms Of Fracture Propagation And Proppant Transport Indeep Coalbed Methane Reservoirs, Guo Xiaodong, Zhang Shicheng, Zhang Jingchen, Zhou Changjing, Zhang Chengsheng, Qiu Shixin, Xi Xiangrui
Coal Geology & Exploration
Objectives and Methods Deep coalbed methane (CBM) reservoirs commonly exhibit well-developed beddings, strong mechanical heterogeneity, and high in-situ stress gradients. These characteristics result in pronounced nonlinear fracture propagation and strong multi-field coupling effects during hydraulic fracturing. Consequently, it is challenging to accurately describe the mechanisms governing fracture complexity in deep coal reservoirs using conventional mechanical models for fractures. Using a super-large true triaxial system with dimensions of 2.0 m × 2.0 m × 1.0 m, this study conducted physical simulation experiments on hydraulic fracturing under varying injection rates and viscosities of fracturing fluids. In combination with fracture mechanics and energy …
Supersaturation Effect And Its Characterization In Gas-Rich Intervals Of Deep Coal Seams, Zhou Lihong, Li Yong, Ding Rong, Li Yun, Li Yongzhou, Kong Jintao
Supersaturation Effect And Its Characterization In Gas-Rich Intervals Of Deep Coal Seams, Zhou Lihong, Li Yong, Ding Rong, Li Yun, Li Yongzhou, Kong Jintao
Coal Geology & Exploration
Objective and Method High free gas content serves as a key factor controlling the enrichment and high productivity of deep coalbed methane (CBM). However, its direct determination is challenging, making the accurate identification of free gas-rich coal seam intervals a core scientific issue for efficient exploration and recovery of CBM. This study investigated the Daning-Jixian block (also referred to as the Daji Block) within the Ordos Basin. Based on analyses and tests of the gas content, coal macrolithotype, physical properties, and log responses of cores collected from representative wells through pressure-retained coring, this study systematically assessed the vertical heterogeneity of …
Diagnosis, Prevention, And Control Of Liquid Accumulation In Horizontal Wellbores For Deep Coalbed Methane: A Case Study Of The Daning-Jixian Block Along The Eastern Margin Of The Ordos Basin, Zeng Wenting, Wang Zhiming, Zhang Lei, Tian Zhida, Zhen Huaibin, Dai Anna, Zeng Quanshu, Sui Tianyang
Diagnosis, Prevention, And Control Of Liquid Accumulation In Horizontal Wellbores For Deep Coalbed Methane: A Case Study Of The Daning-Jixian Block Along The Eastern Margin Of The Ordos Basin, Zeng Wenting, Wang Zhiming, Zhang Lei, Tian Zhida, Zhen Huaibin, Dai Anna, Zeng Quanshu, Sui Tianyang
Coal Geology & Exploration
Objective The Daning-Jixian block on the eastern margin of the Ordos Basin has achieved large-scale production of deep coalbed methane (CBM), with nearly 150 horizontal wells having been put into production. However, with a gradual decrease in formation energy during CBM production, gas wells exhibit declining liquid-carrying capacity. Consequently, liquid accumulation in wellbores has become a major factor affecting deep CBM production. Recovery of deep CBM shows the coexistence of free and desorbed gases, accompanied by significantly varying gas/liquid ratios. Moreover, gas production channels and techniques vary in different production stages. Hence, there is an urgent need to develop a …
Chemical Temporary Plugging-Based Full-Bore Reconstruction Technology For Old Wellbores For The Collaborative Production Of Tight-Sand Gas And Deep Coalbed Methane, Yang Fan, Tan Zhanglong, Hu Jiachen, An Qi, Li Yu, Yang Ruiyue, Lin Junwen, Sun Zening, Jing Meiyang
Chemical Temporary Plugging-Based Full-Bore Reconstruction Technology For Old Wellbores For The Collaborative Production Of Tight-Sand Gas And Deep Coalbed Methane, Yang Fan, Tan Zhanglong, Hu Jiachen, An Qi, Li Yu, Yang Ruiyue, Lin Junwen, Sun Zening, Jing Meiyang
Coal Geology & Exploration
Objective In China, the Ordos Basin boasts abundant coal-measure gas resources, holding considerable potential for resource development. As the development deepens, the proportion of depleted, stripper, and inefficient wells for tight-sand gas in coal measures has gradually decreased year by year. The collaborative production of tight-sand gas and deep coalbed methane (CBM) has emerged as a significant approach to effectively releasing production capacity.Methods To achieve the reconstruction of old wellbores and commingled production of new and old layers, this study proposed a technology of chemical temporary plugging-based full-bore reconstruction of old wellbores of tight-sand gas combined with the large-scale …
Prediction Of Geological And Engineering Integrated Sweet Spots Of Deep Coalbed Methane, Chen Zhengrong, Liu Wei, Zhu Xueshen, Tian Yongjing, Xie Xin
Prediction Of Geological And Engineering Integrated Sweet Spots Of Deep Coalbed Methane, Chen Zhengrong, Liu Wei, Zhu Xueshen, Tian Yongjing, Xie Xin
Coal Geology & Exploration
Objective Deep coalbed methane (CBM) has emerged as a hot topic in CBM resource development. However, deep CBM has characteristics such as great burial depths, complex stress environments, and strong reservoir heterogeneity, which seriously restrict sweet spot prediction and accurate well location deployment in its large-scale exploitation. Methods This study investigated a deep CBM field along the eastern margin of the Ordos Basin. Using sonic, density, and caliper logging, this study developed a coal structure index model for deep coals. By introducing the coal structure index based on the coal structure differences in deep coal seams and combining factors including …
Dominant Geological And Engineering Factors Controlling The Productivity Of Horizontal Wells For Deep Coalbed Methane In The Southern Shenfu Block, Guo Guangshan, Liu Yancheng, Zhao Gang, Chen Zhaohui, Li Chen, Kang Lifang, Wang Yuchuan, Wang Jianan
Dominant Geological And Engineering Factors Controlling The Productivity Of Horizontal Wells For Deep Coalbed Methane In The Southern Shenfu Block, Guo Guangshan, Liu Yancheng, Zhao Gang, Chen Zhaohui, Li Chen, Kang Lifang, Wang Yuchuan, Wang Jianan
Coal Geology & Exploration
Objective The southern Shenfu block along the eastern margin of the Ordos Basin hosts one of the rare gas fields with reserves of over 100 billion cubic meters (bcm) in China, serving as a pilot demonstration area for the exploration and production of deep coalbed methane (CBM) conducted by the China National Offshore Oil Corporation (CNOOC). In this block, the gas production of horizontal wells is 2-10 times that of vertical wells. However, the horizontal wells are challenged by significantly different and rapidly declining gas production. Determining dominant factors controlling the productivity of horizontal wells for deep CBM is the …
Dynamic Gas Supply Mechanism And Theoretical Production Modes Of Free Gas-Rich Deep Coal Reservoirs, Chen Shida, Zhang Taiyuan, Tang Dazhen, Xu Hao, Tao Shu, Li Song, Tang Shuling
Dynamic Gas Supply Mechanism And Theoretical Production Modes Of Free Gas-Rich Deep Coal Reservoirs, Chen Shida, Zhang Taiyuan, Tang Dazhen, Xu Hao, Tao Shu, Li Song, Tang Shuling
Coal Geology & Exploration
Objective and Methods The production processes of adsorbed and free gases and the dynamic partitioning mechanism behind the production efficiency of both gas types are critical scientific issues to be addressed urgently in the exploration and production of deep coalbed methane (CBM). Based on the test and assay data of cores from exploration wells, this study systematically analyzed the theoretical production of deep CBM resources. By integrating the building of mathematical and numerical models, carbon isotope monitoring of methane, and the analysis of production curves, this study revealed the spatiotemporal evolutionary processes of production-induced pressure drop expansion, adsorbed gas desorption, …
Application Of Five Seismic Attributes In Natural Fracture Prediction For Deep Coalbed Methane Production Along The Eastern Margin Of The Ordos Basin, Tong Jiangnan, Wang Feng, Zhang Feng, Hou Wei, Li Zhongbai, Ji Liang, Jiang Yanan, Sun Wei
Application Of Five Seismic Attributes In Natural Fracture Prediction For Deep Coalbed Methane Production Along The Eastern Margin Of The Ordos Basin, Tong Jiangnan, Wang Feng, Zhang Feng, Hou Wei, Li Zhongbai, Ji Liang, Jiang Yanan, Sun Wei
Coal Geology & Exploration
Background Natural fractures serve as both the primary storage space for free gas of deep coalbed methane (CBM) and pathways for hydrocarbon migration. Furthermore, these fractures can enhance the porosity and permeability of strata under the deep, high-pressure condition, significantly amplifying the permeability of coal seams. Therefore, the fine-scale characterization of the planar distribution of natural fractures is crucial to deep CBM production.Objectives and Methods This study investigated the No.8 coal seam in the Carboniferous Benxi Formation within the Daning-Jixian block on the eastern margin of the Ordos Basin. Through offset vector tiles (OVT) domain processing of offshore 3D …
Critical Technologies And Geology-Engineering Integration Practices For Deep Cbm Production In The Yanchuannan Cbm Field, Chen Zhenlong, Wang Yunhai, Liu Xiao, Cui Bin, Yang Song, Li Xin, Fang Qilong
Critical Technologies And Geology-Engineering Integration Practices For Deep Cbm Production In The Yanchuannan Cbm Field, Chen Zhenlong, Wang Yunhai, Liu Xiao, Cui Bin, Yang Song, Li Xin, Fang Qilong
Coal Geology & Exploration
Objective and Methods This study introduces the adjustments for coalbed methane (CBM) production in the Yanchuannan CBM field‒the first deep CBM field in China. Deep CBM production in this CBM field faces challenges including strong heterogeneity of reservoirs, single arrangement mode of production well patterns, low applicability of conventional hydraulic fracturing, excessively long conventional production cycles, and a high proportion of inefficient wells. To address these challenges, a production capacity construction model for efficient deep CBM production of the field was developed through in-depth geology-engineering integration. Results and Conclusions The results indicate that the production capacity construction process of the …
Key Experimental Technologies And Their Development Directions For The Exploration And Production Of Deep Coalbed Methane, Yan Xia, Xu Fengyin, Xiong Xianyue, Wang Feng, Li Chunhu, Zhang Jiyuan, Xu Borui, Cheng Qianhui, Hu Xiong, Zhu Xueguang, Liang Wei, Yuan Pu, Feng Yanqing, Wei Zhenji
Key Experimental Technologies And Their Development Directions For The Exploration And Production Of Deep Coalbed Methane, Yan Xia, Xu Fengyin, Xiong Xianyue, Wang Feng, Li Chunhu, Zhang Jiyuan, Xu Borui, Cheng Qianhui, Hu Xiong, Zhu Xueguang, Liang Wei, Yuan Pu, Feng Yanqing, Wei Zhenji
Coal Geology & Exploration
Objective Deep coalbed methane (CBM) production enjoys advantages including rapid gas shows, high single-well yield, and continuous resource distribution, which establish deep CBM as a significant target for reserve growth and production addition of natural gas. However, the exploration and production of deep CBM are still confronted with many technical challenges, and there is a lack of studies on key experimental technologies related to the geological characteristics and engineering assessment of deep CBM reservoirs, the occurrence characteristics and production mechanisms of gas and water, the formulation of production systems, and methods for enhanced CBM recovery. Advances in Research Given the …
Characteristics Of The Pore And Seepage System Of Deep Coalbed Methane In The Baijiahai Uplift, Junggar Basin, Xinjiang, Chen Heqing, Yang Zhaobiao, Li Daoqing, Xu Miaomiao, Liang Yuhui, Liu Changqing, Wang Yuqiang
Characteristics Of The Pore And Seepage System Of Deep Coalbed Methane In The Baijiahai Uplift, Junggar Basin, Xinjiang, Chen Heqing, Yang Zhaobiao, Li Daoqing, Xu Miaomiao, Liang Yuhui, Liu Changqing, Wang Yuqiang
Coal Geology & Exploration
[Objective] Xinjiang boasts abundant deep coalbed methane (CBM) resources, with Jurassic coal seams in the Baijiahai uplift of the Junggar Basin identified as a favorable target area for deep CBM exploration and exploitation. The pore and seepage system of deep CBM directly determines its recoverability. [Methods] Based on appraisal well Caimei 2-004H drilled the most recently in the Xinjiang oilfield in 2023, this study investigated in detail the pore and seepage system of coals in the Jurassic Xishanyao Formation in the Baijiahai uplift using scanning electron microscopy (SEM) observations, mercury injection capillary pressure (MICP), low-temperature liquid nitrogen adsorption, and carbon …