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Influence of Drilling Fluid Components on Shear Strength at Cement-aquifuge Interface in Coalbed Methane Wells 被引量:1
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作者 GU Jun WANG Shuai +2 位作者 MA Chao GAN Pin TANG Naiqian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第4期1511-1512,共2页
The hydraulic fracturing is still an effective technology for the exploitation of coalbed methane (CBM). However, after the hydraulic fracturing operation, the high water cut or sudden water flooding of CBM well usu... The hydraulic fracturing is still an effective technology for the exploitation of coalbed methane (CBM). However, after the hydraulic fracturing operation, the high water cut or sudden water flooding of CBM well usually occurs due to upward migration of bottom water, which is called water channeling (water inrush). This problem has been severely limiting the hydraulic fracturing effect of CBM wells. Some studies show that the aquifuge and cement paste themselves will not crush under hydraulic fracturing pressure. Water channeling often occurs at cement- aquifuge interface (CAI). 展开更多
关键词 Influence of Drilling Fluid Components on Shear Strength at Cement-aquifuge Interface in coalbed methane wells
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Prediction of Flowing Bottomhole Pressures for Two-Phase Coalbed Methane Wells 被引量:5
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作者 LIU Xinfu 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2013年第5期1412-1420,共9页
A method is proposed to predict the flowing bottomhole pressures (FBHPs) for two-phase coalbed methane (CBM) wells. The mathematical models for both gas column pressure and two-phase fluid column pressure were dev... A method is proposed to predict the flowing bottomhole pressures (FBHPs) for two-phase coalbed methane (CBM) wells. The mathematical models for both gas column pressure and two-phase fluid column pressure were developed based on the well liquid flow equation. FBHPs during the production were predicted by considering the effect of entrained liquid on gravitational gradients. Comparison of calculated BHPs by Cullender-Smith and proposed method was also studied. The results show that the proposed algorithm gives the desired accuracy of calculating BHPs in the low- productivity and low-pressure CBM wells. FBHP is resulted from the combined action of wellhead pressure, gas column pressure and fluid column pressure. Variation of kinetic energy term, compressibility and friction factors with depth increments and liquid holdup with velocity should be considered to simulate the real BHPs adequately. BHP is a function of depth of each column segment. The small errors of less than 1.5% between the calculated and measured values are obtained with each segment within 25 m. Adjusting BHPs can effectively increase production pressure drop, which is beneficial to CBM desorption and enhances reservoir productivity. The increment of pressure drop from 5.37 MPa2 to 8.66 MPa2 leads to an increase of CBM production from 3270 m3/d to 6700 m3/d and is attributed to a decrease in BHP from 2.25 MPa to 1.33 MPa. 展开更多
关键词 coalbed methane productivity flowing bottomhole pressure gas column pressure two-phase fluid column pressure
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A dynamic evaluation technique for assessing gas output from coal seams during commingling production within a coalbed methane well: a case study from the Qinshui Basin 被引量:3
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作者 Chuan Wu Chengxiang Yuan +2 位作者 Guojun Wen Lei Han Haojie Liu 《International Journal of Coal Science & Technology》 EI 2020年第1期122-132,共11页
Gas drainage is carried out based on output from each coal bed throughout commingling production of coalbed methane(CBM).A reasonable drainage process should therefore initially guarantee main coal bed production and ... Gas drainage is carried out based on output from each coal bed throughout commingling production of coalbed methane(CBM).A reasonable drainage process should therefore initially guarantee main coal bed production and then enhance gas output from other beds.Permanent damage can result if this is not the case,especially with regard to fracture development in the main gas-producing coal bed and can greatly reduce single well output.Current theoretical models and measuring devices are inapplicable to commingled CBM drainage,however,and so large errors in predictive models cannot always be avoided.The most effective currently available method involves directly measuring gas output from each coal bed as well as determining the dominant gas-producing unit.A dynamic evaluation technique for gas output from each coal bed during commingling CBM production is therefore proposed in this study.This technique comprises a downhole measurement system combined with a theoretical calculation model.Gas output parameters(i.e.,gas-phase flow rate,temperature,pressure)are measured in this approach via a downhole measurement system;substituting these parameters into a deduced theoretical calculation model then means that gas output from each seam can be calculated to determine the main gas-producing unit.Trends in gas output from a single well or each seam can therefore be predicted.The laboratory and field test results presented here demonstrate that calculation errors in CBM outputs can be controlled within a margin of 15%and therefore conform with field use requirements. 展开更多
关键词 Commingling production Gas output Dynamic evaluation coalbed methane Qinshui Basin
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Characteristics of dissolved inorganic carbon in produced water from coalbed methane wells and its geological significance 被引量:2
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作者 YANG Zhaobiao QIN Yong +3 位作者 QIN Zonghao YI Tongsheng LI Cunlei ZHANG Zhengguang 《Petroleum Exploration and Development》 2020年第5期1074-1083,共10页
Based on long-term dynamic tracing of dissolved inorganic carbon(DIC)and stable carbon isotope(δ13CDIC)in produced water from 20 coalbed methane(CBM)wells in western Guizhou,the spatial-temporal dynamic variations of... Based on long-term dynamic tracing of dissolved inorganic carbon(DIC)and stable carbon isotope(δ13CDIC)in produced water from 20 coalbed methane(CBM)wells in western Guizhou,the spatial-temporal dynamic variations ofδ13CDIC of the GP well group produced in multi-layer commingled manner were analyzed,and the relationship between the value ofδ13CDIC and CBM productivity was examined.The produced water samples of typical wells in the GP well group were amplified and sequenced using 16S rDNA,and a geological response model ofδ13CDIC in produced water from CBM wells with multi-coal seams was put forward.The research shows that:δ13CDIC in produced water from medium-rank coal seams commonly show positive anomalies,the produced water contains more than 15 species of methanogens,and Methanobacterium is the dominant genus.The dominant methanogens sequence numbers in the produced water are positively correlated withδ13CDIC,and the positive anomaly of v is caused by reduction of methanogens,and especially hydrogenotrophic methanogens.Vertical segmentation of sedimentary facies and lithology in stratum with multi-coal seams will result in permeability and water cut segmentation,which will lead to the segmentation ofδ13CDIC and archaea community in produced water,so in the strata with better permeability and high water cut,theδ13CDIC of the produced water is abnormally enriched,and the dominant archaea is mainly Methanobacterium.In the strata with weak permeability and low water cut,theδ13CDIC of the produced water is small,and the microbial action is weak.The shallow layer close to the coal seam outcrop is likely to be affected by meteoric precipitation,so theδ13CDIC of the produced water is smaller.The geological response model ofδ13CDIC in produced water from multi-coal seams CBM wells in the medium-rank coal reveals the geological mechanism and microbial action mechanism of theδ13CDIC difference in the produced water from the multi-coal seams CBM wells.It also provides effective geochemical evidence for the superimposed fluid system controlled by sedimentary facies,and can also be used for the contribution analysis of the produced gas and water by the multi-layer CBM wells. 展开更多
关键词 coalbed methane produced water from coal seam dissolved inorganic carbon stable carbon isotope archaea community microbial gene CBM productivity geological response model
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Drainage feature about coalbed methane wells in different hydrogeological conditions in Fanzhuang area 被引量:1
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作者 NI Xiao-ming LIN Ran WANG Yan-bin 《Journal of Coal Science & Engineering(China)》 2012年第4期344-349,共6页
It is an important guarantee to enhance the production of coalbed methane (CBM) and reduce the project invest- ment by finding out the drainage feature about CBM wells in different hydrogeological conditions. Based ... It is an important guarantee to enhance the production of coalbed methane (CBM) and reduce the project invest- ment by finding out the drainage feature about CBM wells in different hydrogeological conditions. Based on the CBM explora- tion and development data on the Fanzhuang block in southeast Qinshui Basin and combined with the seepage principle and lithology on the roof and the bottom coalbed, the mathematical model of integrated permeability was established. By perme- ability experiments of the different lithologies on the roof and the floor within the 20 m range combined with the log curves, the integrated permeability of different lithological combinations were obtained. The starting pressure gradient and permeabi- lity of the roof and the floor for different lithologies was tested by "differential pressure-flow method". The relationships be- tween the starting pressure gradient and the integrated permeability were obtained. The critical distance of limestone water penetrating into coal reservoirs was calculated. According to the drainage feature of CBM wells combined with the drainage data of some CBM wells, the results show that, when limestone water can penetrate into coal reservoirs, the daily water production is high and the daily gas production is low although there is no gas at the beginning of the drainage process, the CBM wells stop discharging water within 6 months after the gas began to come out, and the gas production is steadily improved. When limestone water can not penetrate into coal reservoirs, the daily water production is low and the daily gas production is high at the beginning of the drainage process, and it almost stops discharging water after some time when the gas come out, the daily gas production increases, and the cumulative water production is much lower. 展开更多
关键词 coalbed methane hydrogeologicalv condition drainage feature water production Fanzhuang area
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Extreme massive hydraulic fracturing in deep coalbed methane horizontal wells:A case study of the Linxing Block,eastern Ordos Basin,NW China 被引量:1
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作者 YANG Fan LI Bin +3 位作者 WANG Kunjian WEN Heng YANG Ruiyue HUANG Zhongwei 《Petroleum Exploration and Development》 SCIE 2024年第2期440-452,共13页
Deep coal seams show low permeability,low elastic modulus,high Poisson’s ratio,strong plasticity,high fracture initiation pressure,difficulty in fracture extension,and difficulty in proppants addition.We proposed the... Deep coal seams show low permeability,low elastic modulus,high Poisson’s ratio,strong plasticity,high fracture initiation pressure,difficulty in fracture extension,and difficulty in proppants addition.We proposed the concept of large-scale stimulation by fracture network,balanced propagation and effective support of fracture network in fracturing design and developed the extreme massive hydraulic fracturing technique for deep coalbed methane(CBM)horizontal wells.This technique involves massive injection with high pumping rate+high-intensity proppant injection+perforation with equal apertures and limited flow+temporary plugging and diverting fractures+slick water with integrated variable viscosity+graded proppants with multiple sizes.The technique was applied in the pioneering test of a multi-stage fracturing horizontal well in deep CBM of Linxing Block,eastern margin of the Ordos Basin.The injection flow rate is 18 m^(3)/min,proppant intensity is 2.1 m^(3)/m,and fracturing fluid intensity is 16.5 m^(3)/m.After fracturing,a complex fracture network was formed,with an average fracture length of 205 m.The stimulated reservoir volume was 1987×10^(4)m^(3),and the peak gas production rate reached 6.0×10^(4)m^(3)/d,which achieved efficient development of deep CBM. 展开更多
关键词 deep coalbed methane extreme massive hydraulic fracturing fracture network graded proppants slick water with variable viscosity Ordos Basin
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Excess pore pressure behavior and evolution in deep coalbed methane reservoirs
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作者 Changqing Liu Zhaobiao Yang +3 位作者 Yong Qin Xia Yan Yunhai Wang Zhe Wang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第6期763-781,共19页
Deep coalbed methane(DCBM),an unconventional gas reservoir,has undergone significant advancements in recent years,sparking a growing interest in assessing pore pressure dynamics within these reservoirs.While some prod... Deep coalbed methane(DCBM),an unconventional gas reservoir,has undergone significant advancements in recent years,sparking a growing interest in assessing pore pressure dynamics within these reservoirs.While some production data analysis techniques have been adapted from conventional oil and gas wells,there remains a gap in the understanding of pore pressure generation and evolution,particularly in wells subjected to large-scale hydraulic fracturing.To address this gap,a novel technique called excess pore pressure analysis(EPPA)has been introduced to the coal seam gas industry for the first time to our knowledge,which employs dual-phase flow principles based on consolidation theory.This technique focuses on the generation and dissipation for excess pore-water pressure(EPWP)and excess pore-gas pressure(EPGP)in stimulated deep coal reservoirs.Equations have been developed respectively and numerical solutions have been provided using the finite element method(FEM).Application of this model to a representative field example reveals that excess pore pressure arises from rapid loading,with overburden weight transferred under undrained condition due to intense hydraulic fracturing,which significantly redistributes the weight-bearing role from the solid coal structure to the injected fluid and liberated gas within artificial pores over a brief timespan.Furthermore,field application indicates that the dissipation of EPWP and EPGP can be actually considered as the process of well production,where methane and water are extracted from deep coalbed methane wells,leading to consolidation for the artificial reservoirs.Moreover,history matching results demonstrate that the excess-pressure model established in this study provides a better explanation for the declining trends observed in both gas and water production curves,compared to conventional practices in coalbed methane reservoir engineering and petroleum engineering.This research not only enhances the understanding of DCBM reservoir behavior but also offers insights applicable to production analysis in other unconventional resources reliant on hydraulic fracturing. 展开更多
关键词 Deep coalbed methane CONSOLIDATION Excess pore-water pressure Excess pore-gas pressure Production data analysis
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Productivity matching and quantitative prediction of coalbed methane wells based on BP neural network 被引量:9
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作者 LU YuMin TANG DaZhen +1 位作者 XU Hao TAO Shu 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第5期1281-1286,共6页
It is a great challenge to match and predict the production performance of coalbed methane (CBM) wells in the initial production stage due to heterogeneity of coalbed, uniqueness of CBM production process, complexity ... It is a great challenge to match and predict the production performance of coalbed methane (CBM) wells in the initial production stage due to heterogeneity of coalbed, uniqueness of CBM production process, complexity of porosity-permeability variation and difficulty in obtaining some key parameters which are critical for the conventional prediction methods (type curve, material balance and numerical simulation). BP neural network, a new intelligent technique, is an effective method to deal with nonlinear, instable and complex system problems and predict the short-term change quantitatively. In this paper a BP neural model for the CBM productivity of high-rank CBM wells in Qinshui Basin was established and used to match the past gas production and predict the futural production performance. The results from two case studies showed that this model has high accuracy and good reliability in matching and predicting gas production with different types and different temporal resolutions, and the accuracy increases as the number of outliers in gas production data decreases. Therefore, the BP network can provide a reliable tool to predict the production performance of CBM wells without clear knowledge of coalbed reservoir and sufficient production data in the early development stage. 展开更多
关键词 BP neural network coalbed methane well productivity matching quantitative prediction
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The status and development strategy of coalbed methane industry in China 被引量:2
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作者 XU Fengyin HOU Wei +11 位作者 XIONG Xianyue XU Borui WU Peng WANG Hongya FENG Kun YUN Jian LI Shuguang ZHANG Lei YAN Xia FANG Huijun LU Qian MAO Delei 《Petroleum Exploration and Development》 SCIE 2023年第4期765-783,共19页
To achieve the goals of carbon peaking and carbon neutrality under the backgrounds of poor resource endowments, weak theoretical basis and other factors, the development of the coalbed methane industry of China faces ... To achieve the goals of carbon peaking and carbon neutrality under the backgrounds of poor resource endowments, weak theoretical basis and other factors, the development of the coalbed methane industry of China faces many bottlenecks and challenges. This paper systematically analyzes the coalbed methane resources, key technologies and progress, exploration effect and production performance in China and abroad. The main problems are summarized as low exploration degree, low technical adaptability, low return on investment and small development scale. This study suggests that the coalbed methane industry in China should follow the “two-step”(short-term and long-term) development strategy. The short-term action before 2030, can be divided into two stages:(1) From the present to 2025, to achieve new breakthroughs in theory and technology, and accomplish the target of annual production of 10 billion cubic meters;(2) From 2025 to 2030, to form the technologies suitable for most geological conditions, further expand the industry scale, and achieve an annual output of 30 billion cubic meters, improving the proportion of coalbed methane in the total natural gas production. The long-term action after 2030 is to gradually realize an annual production of 100 billion cubic meters. The strategic countermeasure to achieve the above goals is to adhere to “technology+management dual wheel drive”, realize the synchronous progress of technology and management, and promote the high-quality development of the coalbed methane industry. Technically, the efforts will focus on fine and effective development of coalbed methane in the medium to shallow layers of mature fields, effective development of coalbed methane in new fields, extensive and beneficial development of deep coalbed methane, three-dimensional comingled development of coalbed methane, applying new technologies such as coalbed methane displacement by carbon dioxide, microwave heating and stimulation technology, ultrasonic stimulation, high-temperature heat injection stimulation, rock breaking by high-energy laser. In terms of management, the efforts will focus on coordinative innovation of resource, technology, talent, policy and investment, with technological innovation as the core, to realize an all-round and integrated management and promote the development of coalbed methane industry at a high level. 展开更多
关键词 coalbed methane industry status strategic goal development countermeasures combined gas mining enhanced recovery in-situ conversion
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Exploitation technology of pressure relief coalbed methane in vertical surface wells in the Huainan coal mining area 被引量:13
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作者 HAN Jia-zhang SANG Shu-xun +1 位作者 CHENG Zhi-zhong HUANG Hua-zhou 《Mining Science and Technology》 EI CAS 2009年第1期25-30,共6页
Exploitation technology of pressure relief coalbed methane in vertical surface wells is a new method for exploration of gas and coalbed methane exploitation in mining areas with high concentrations of gas, where tecto... Exploitation technology of pressure relief coalbed methane in vertical surface wells is a new method for exploration of gas and coalbed methane exploitation in mining areas with high concentrations of gas, where tectonic coal developed. Studies on vertical surface well technology in the Huainan Coal Mining area play a role in demonstration in the use of clean, new energy resources, preventing and reducing coal mine gas accidents and protecting the environment. Based on the practice of gas drainage engineering of pressure relief coalbed methane in vertical surface wells and combined with relative geological and exploration en- gineering theories, the design principles of design and structure of wells of pressure relief coalbed methane in vertical surface wells are studied. The effects of extraction and their causes are discussed and the impact of geological conditions on gas production of the vertical surface wells are analyzed. The results indicate that in mining areas with high concentrations of gas, where tectonic coal developed, a success rate of pressure relief coalbed methane in surface vertical well is high and single well production usually great. But deformation due to coal exploitation could damage boreholes and cause breaks in the connection between aquifers and bore-holes, which could induce a decrease, even a complete halt in gas production of a single well. The design of well site location and wellbore configuration are the key for technology. The development of the geological conditions for coalbed methane have a significant effect on gas production of coalbed methane wells. 展开更多
关键词 pressure relief coalbed methane EXPLOITATION vertical surface well Huainan coal mining area
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The coalbed methane production potential method for optimization of wells location selection 被引量:11
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作者 Feng-Ke DOU Yong-Shang KANG +2 位作者 Shao-Feng QIN De-Lei MAO Jun HAN 《Journal of Coal Science & Engineering(China)》 2013年第2期210-218,共9页
A gas production potential method for optimization of gas wellsite locations selection is proposed in terms of the coalbed gas resources volume and the recoverability. The method uses the actual data about reservoirs ... A gas production potential method for optimization of gas wellsite locations selection is proposed in terms of the coalbed gas resources volume and the recoverability. The method uses the actual data about reservoirs in a coalbed gas field in central China to optimize wellsite locations in the studied area in combination with the dynamic data about actual production in the coalbed gas field, selects a favorable subarea for gas wells deployment. The method is established based on the basic properties of coal reservoirs, in combination with the coalbed thickness and the gas content to make an analysis of the gas storage potential of a coal reservoir, as well as resources volume and the permeability of a coal reservoir. This method can be popularized for optimization of wellsite locations in other methane gas development areas or blocks. 展开更多
关键词 coalbed methane gas potential gas production potential method optimization of wellsite locations
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Optimum location of surface wells for remote pressure relief coalbed methane drainage in mining areas 被引量:9
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作者 HUANG, Huazhou SANG, Shuxun +3 位作者 FANG, Liangcai LI, Guojun XU, Hongjie REN, Bo 《Mining Science and Technology》 EI CAS 2010年第2期230-237,共8页
Based on engineering tests in the Huainan coal mining area,we studied alternative well location to improve the performance of surface wells for remote pressure relief of coalbed methane in mining areas.The key factors... Based on engineering tests in the Huainan coal mining area,we studied alternative well location to improve the performance of surface wells for remote pressure relief of coalbed methane in mining areas.The key factors,affecting location and well gas production were analyzed by simulation tests for similar material.The exploitation results indicate that wells located in various positions on panels could achieve relatively better gas production in regions with thin Cenozoic layers,low mining heights and slow rate of longwall advancement,but their periods of gas production lasted less than 230 days,as opposed to wells in regions with thick Cenozoic layers,greater mining heights and fast rates of longwall advancement.Wells near panel margins achieved relatively better gas production and lasted longer than centerline wells.The rules of development of mining fractures in strata over panels control gas production of surface wells.Mining fractures located in areas determined by lines of compaction and the effect of mining are well developed and can be maintained for long periods of time.Placing the well at the end of panels and on the updip return airway side of panels,determined by lines of compaction and the effect of mining,would result in surface wells for remote pressure relief CBM obtaining their longest gas production periods and highest cumulative gas production. 展开更多
关键词 pressure relief coalbed methane surface wells well location Huainan coal mining area
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Fuzzy pattern recognition model of geological sweetspot for coalbed methane development
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作者 LIU Gaofeng LIU Huan +3 位作者 XIAN Baoan GAO Deli WANG Xiaoming ZHANG Zhen 《Petroleum Exploration and Development》 SCIE 2023年第4期924-933,共10页
From the perspective of geological zone selection for coalbed methane(CBM) development, the evaluation parameters(covering geological conditions and production conditions) of geological sweetspot for CBM development a... From the perspective of geological zone selection for coalbed methane(CBM) development, the evaluation parameters(covering geological conditions and production conditions) of geological sweetspot for CBM development are determined, and the evaluation index system of geological sweetspot for CBM development is established. On this basis, the fuzzy pattern recognition(FPR) model of geological sweetspot for CBM development is built. The model is applied to evaluate four units of No.3 Coal Seam in the Fanzhuang Block, southern Qinshui Basin, China. The evaluation results are consistent with the actual development effect and the existing research results, which verifies the rationality and reliability of the FPR model. The research shows that the proposed FPR model of geological sweetspot for CBM development does not involve parameter weighting which leads to uncertainties in the results of the conventional models such as analytic hierarchy process and multi-level fuzzy synthesis judgment, and features a simple computation without the construction of multi-level judgment matrix. The FPR model provides reliable results to support the efficient development of CBM. 展开更多
关键词 coalbed methane development geological sweetspot evaluation index system analytic hierarchy process multi-level fuzzy synthesis judgment fuzzy pattern recognition
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Integrity and Failure Analysis of Cement Sheath Subjected to Coalbed Methane Fracturing
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作者 Lingyun Zhao Heng Yang +3 位作者 Yuanlong Wei Yuhuan Bu Shaorui Jing Peiming Zhou 《Fluid Dynamics & Materials Processing》 EI 2023年第2期329-344,共16页
Perforation and fracturing are typically associated with the development of coalbed methane wells.As the cement sheath is prone to failure during this process,in this work,the effects of the casing pressure,elastic mo... Perforation and fracturing are typically associated with the development of coalbed methane wells.As the cement sheath is prone to failure during this process,in this work,the effects of the casing pressure,elastic modulus of the cement,elastic modulus of the formation,and casing eccentricity on the resulting stresses are analyzed in the frame of a finite element method.Subsequently,sensitivity response curves of the cement sheath stress are plotted by normalizing all factors.The results show that the maximum circumferential stress and Mises stress of the cement sheath increase with the casing internal pressure,elastic modulus of the cement and casing eccentricity.As the elastic modulus of the formation increases,the maximum circumferential stress of the cement sheath decreases,and its maximum Mises stress increases slightly.The cement sheath undergoes tensile failure during coalbed methane fracturing.The stress sensitivity of the cement sheath to the influential parameters is in the following order:casing internal pressure>elastic modulus of cement sheath>casing eccentricity>elastic modulus of formation. 展开更多
关键词 coalbed methane fracturing finite element method cement sheath integrity sensitivity analysis failure analysis
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Finite element analysis of high-pressure hose for radial horizontal wells in coalbed methane extraction 被引量:3
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作者 Wei-Dong ZHOU Wei SHI Luo-Peng LI Jing-Shuang WANG Jun SUN 《Journal of Coal Science & Engineering(China)》 2013年第2期182-186,共5页
Based on the serial-parallel model of single-layer board and the lamination theory, the forces exerted on different layers of the high-pressure hose and the resulting deformations were analyzed when the hose was radia... Based on the serial-parallel model of single-layer board and the lamination theory, the forces exerted on different layers of the high-pressure hose and the resulting deformations were analyzed when the hose was radially stretched. An equation was proposed to calculate the anisotropic elastic constant of the composite layer with the wound steel wires. Furthermore, the finite element analysis (FEA) model of the high-pressure hose was established, followed by a simulation of the forces that act on different layers, and their deformations. The simulation results show that the stress imposed on the inner reinforced layer and external reinforced layer of the high-pressure hose are approximately 150 MPa and 115 MPa, respectively, in the presence of inner pressure. The stress of the rubber coating and polyethylene coating is lower. The lowest stress occurs on the inner surface of the high-pressure hose and the rubber coating between the two composite layers. The deformation of the rubber layer in the inner surface of the high-pressure hose decreases gradually along the radial direction from the inner surface to the external surface. The deformation of the reinforced composite layer is less than that of the external surface of the rubber coating. The equivalent stress of the reinforced composite layer is higher than that caused by the inner pressure, due to the presence of both inner pressure and axial tension. 展开更多
关键词 coalbed methane radial horizontal well high-pressure hose finite element analysis
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Application of Horizontal Well Seismic Geo-Steering Technology in XX Block Development
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作者 Xuecheng Jia Xiaoyi Cheng +4 位作者 Hui Ma Shilei Lu Xin Yang Shuo Wang Xiang Li 《Open Journal of Yangtze Oil and Gas》 2024年第3期65-74,共10页
During the development phase horizontal wells are very efficient way to improve the production in the deep coal bed methane. The 8# coal seam in the XX block on the eastern edge of the Ordos Basin has challenges such ... During the development phase horizontal wells are very efficient way to improve the production in the deep coal bed methane. The 8# coal seam in the XX block on the eastern edge of the Ordos Basin has challenges such as deep burial depth (>2000 m), thin coal sweet spot (3 m), and significant short-distance structural fluctuations. The challenges caused a high risk of missing targets and running out of the target layers, as well as difficulties in cementing and completion due to uneven well trajectories. To address these challenges, this paper focuses on solving the issues through detailed precise geological modeling, optimized trajectory design, and accurate seismic geology Steerable Drilling. 1) Based on reasonable velocity field construction and Time-Depth transformation, a precise directional model is constructed using the layer-by-layer approximation principle with reference to marker layers, improving the accuracy of the target spot and avoiding premature or delayed entry into the target;2) Based on a precise geological model, the dip angle of the strata ahead and the development of sweet spots are clearly defined, enabling optimized trajectory design for horizontal wells;3) Using “1 + N” dynamic modeling to update the geological model in real-time during the drilling process, and actively guide the drill bit through the horizontal segment smoothly by using multi-information judgment of the drill bit position. The actual drilling of 80 completed horizontal wells in this area show: That this approach effectively ensures the smooth trajectory and high-quality drilling rate of the horizontal well in the coal seam, providing a basis for subsequent hydraulic fracturing and increasing single-well production. At the same time, it has certain potential value and significance for similar coalbed methane developments under similar geological conditions. 展开更多
关键词 Seismic Geo-Steerable Horizontal wells coalbed methane Marker Layers
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Coalbed methane genesis, occurrence and accumulation in China 被引量:31
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作者 Song Yan Liu Shaobo +3 位作者 Zhang Qun Tao Mingxin Zhao Mengjun Hong Feng 《Petroleum Science》 SCIE CAS CSCD 2012年第3期269-280,共12页
Coalbed methane (CBM) is an important type of unconventional gas. Commercial development of CBM in America has been very successful since the 1980s. The CBM industry in Australia and Canada has developed rapidly dur... Coalbed methane (CBM) is an important type of unconventional gas. Commercial development of CBM in America has been very successful since the 1980s. The CBM industry in Australia and Canada has developed rapidly during the last decade. Commercial development of CBM in China started in the 1990s, and has made great progress. The geological theory of CBM in China has achieved great advancement in genesis, occurrence and accumulation. On the aspect of CBM genesis, five CBM genetic types (primary biogenic gas, secondary biogenic gas, thermal degradation gas, pyrolysis gas and mixed gas) are identified by studying the geochemical characteristics of CBM, and a tracing indicator system is established. The discovery of secondary biogenic gas in medium-high rank coal reservoirs has widened the potential of CBM resources. On the aspect of CBM occurrence, the gas adsorption regulation under combined action of temperature and pressure is revealed by conducting adsorption experiments of different coal ranks under varying temperature and pressure conditions. Besides, by applying the adsorption potential theory in CBM research, the adsorption model under combined action of temperature and pressure is established. The new model can predict CBM resources accurately, and overcome the limitation of the traditional Langmuir model which uses just a single factor to describe the adsorption characteristics of deep buried coal. On the aspect of CBM accumulation, it is proposed that there are three evolutionary stages during CBM accumulation, including gas generation and adsorption, unsaturated gas adsorption, gas desorption-diffusion and preservation. Controlled by tectonic evolution, hydrodynamics and sealing conditions, CBM tends to be regionally enriched in synclines. Advances in geological theory of CBM in China can not only improve understanding of natural gas, but also provide new ideas for further exploration of CBM. 展开更多
关键词 China coalbed methane genetic type secondary biogenic gas adsorption model syncline enrichment
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A Comprehensive Model for Evaluating Coalbed Methane Reservoirs in China 被引量:19
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作者 YAO Yanbin LIU Dameng TANG Dazhen HUANG Wenhui TANG Shuheng CHE Yao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2008年第6期1253-1270,共18页
Coalbed methane reservoir (CBMR) evaluation is important for choosing the prospective target area for coalbed methane exploration and production. This study aims at identifying the characteristic parameters and meth... Coalbed methane reservoir (CBMR) evaluation is important for choosing the prospective target area for coalbed methane exploration and production. This study aims at identifying the characteristic parameters and methods to evaluate CBMR. Based on the geological surveys, laboratory measurements and field works, a four-level analytic hierarchy process (AHP) model for CBMR evaluation is proposed. In this model, different weights are prioritized and assigned on the basis of three main criteria (including reservoir physical property, storage capacity and geological characteristics), 15 sub-criteria, and 18 technical alternatives; the later of which are discussed in detail. The model was applied to evaluate the CBMR of the Permo-Carboniferous coals in the Qinshui Basin, North China. This GIS-based fuzzy AHP comprehensive model can be used for the evaluation of CBMR of medium-high rank (mean maximum vitrinite reflectance 〉0.5 %) coal districts in China. 展开更多
关键词 coalbed methane reservoir reservoir evaluation reservoir characterization comprehensive model Fuzzy Hierarchy Process Approach (FAHP)
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The Classification and Model of Coalbed Methane Reservoirs 被引量:16
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作者 SUXianbo LINXiaoying +1 位作者 SONGYan ZHAOMengjun 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第3期662-666,共5页
Coalbed methane has been explored in many basins worldwide for 30 years, and has been developed commercially in some of the basins. Many researchers have described the characteristics of coalbed methane geology and te... Coalbed methane has been explored in many basins worldwide for 30 years, and has been developed commercially in some of the basins. Many researchers have described the characteristics of coalbed methane geology and technology systematically. According to these investigations, a coalbed methane reservoir can be defined: 'a coal seam that contains some coalbed methane and is isolated from other fluid units is called a coalbed methane reservoir'. On the basis of anatomization, analysis, and comparison of the typical coalbed methane reservoirs, coalbed methane reservoirs can be divided into two classes: the hydrodynamic sealing coalbed methane reservoirs and the self-sealing coalbed methane reservoirs. The former can be further divided into two sub-classes: the hydrodynamic capping coalbed methane reservoirs, which can be divided into five types and the hydrodynamic driving coalbed methane reservoirs, which can be divided into three types. The latter can be divided into three types. Currently, hydrodynamic sealing reservoirs are the main target for coalbed methane exploration and development; self-sealing reservoirs are unsuitable for coalbed methane exploration and development, but they are closely related with coal mine gas hazards. Finally, a model for hydrodynamic sealing coalbed methane reservoirs is established. 展开更多
关键词 coalbed methane reservoir CLASSIFICATION reservoir model HYDRODYNAMICS reservoir boundary
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Coalbed Methane-bearing Characteristics and Reservoir Physical Properties of Principal Target Areas in North China 被引量:15
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作者 TANGShuheng SUNShenglin +1 位作者 HAODuohu TANGDazhen 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第3期724-728,共5页
The coalbed methane (CBM) resources in North China amounts up to 60% of total resources in China. North China is the most important CBM accumulation area in China. The coal beds of the Upper Paleozoic Taiyuan and Shan... The coalbed methane (CBM) resources in North China amounts up to 60% of total resources in China. North China is the most important CBM accumulation area in China. The coal beds of the Upper Paleozoic Taiyuan and Shanxi formations have a stable distribution. The coal reservoir of target areas such as Jincheng, Yanquan-Shouyang, Hancheng, Liulin, etc. have good CBM-bearing characteristics, high permeability and appropriate reservoir pressure, and these areas are the preferred target areas of CBM developing in China. The coal reservoirs of Wupu, Sanjiaobei, Lu'an, Xinmi, Anyang-Hebi, Jiaozuo, Xinggong and Huainan also have as good CBM-bearing characteristics, but the physical properties of coal reservoirs vary observably. So, further work should be taken to search for districts with high pressure, high permeability and good CBM-bearing characteristics. Crustal stresses have severe influence on the permeability of coal reservoirs in North China. From west to east, the crustal stress gradient increases, while the coal reservoirs permeability decreases. 展开更多
关键词 coalbed methane (CBM) coal reservoir physical property crustal stress North China
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