注热联合井群开采煤层气运移采出规律数值模拟
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摘要
为总结注热联合井群开采低渗透储层煤层气运移采出规律,基于传热学、弹性力学、渗流力学、岩石力学理论,建立了注蒸汽开采低渗透储层煤层气藏过程的热固流耦合数学模型。结合潞安矿区山西组3#煤层地质参数,利用有限元软件进行了注热联合井群开采煤层气藏运移规律的数值模拟,得到了不同布井方式下注热10d、开采100d过程中煤层温度场、应力场及煤层气渗流场变化规律。结果显示,煤层平均传热速度为1.57m/d,注热10d后,中心井35m范围内为有效注热区;随井筒数量的增加和井间距的减小,井间干扰作用增强,煤储层压力下降加快,煤层气供气及解吸区域增加,累积产量显著增加。七井模型20m井间距注热开采累积产气量是五井模型30m井间距未注热开采累积产气量的2.01倍。模拟结果显示了注热和井间干扰开采优势,为低渗透储层煤层气井群注热联合工业开采提供理论依据。
In order to obtain the migration and output laws of low permeability coalbed methane in mining of well group combined with thermal injection,a coupled thermal-solid-fluid mathematical model of coalbed methane was developed based on the theory of heat transfer,elastic mechanics,seepage mechanics,and rock mechanics.Combined with the geological parameters of 3# coal seam of Shanxi Formation in Lu'an mining area,the finite software was utilized to simulate seepage rules in the mining process.Under different well pattern,10 dthermal stimulation and 100 d mining were carried out respectively,and the curves of related parameters,temperature,and stress and gas pressure variation were drawn.The results show that the average velocity of heat transfer of coal seam is 1.57 m/d after 10 d steam injection in the 35 meffective area of thermal stimulation.With the increase of well number and the decrease of well spacing,along the radial direction of well,the well group interference is strengthened,the reservoir pressure drops more quickly,the gas desorption area increases,and the production of well is promoted significantly.The production of cumulative coalbed methane of seven wells heat injection with 20 mwell-bore spacing is 2.01 times of that of five wells with 30 mwell-bore spacing without heat injection.The simulation results show the advantages of heat injection and interwell interference,and provide a theoretical basis for coalbed methane mining technology of multi-well combined with thermal injection in low permeability reservoirs.
In order to obtain the migration and output laws of low permeability coalbed methane in mining of well group combined with thermal injection,a coupled thermal-solid-fluid mathematical model of coalbed methane was developed based on the theory of heat transfer,elastic mechanics,seepage mechanics,and rock mechanics.Combined with the geological parameters of 3# coal seam of Shanxi Formation in Lu'an mining area,the finite software was utilized to simulate seepage rules in the mining process.Under different well pattern,10 dthermal stimulation and 100 d mining were carried out respectively,and the curves of related parameters,temperature,and stress and gas pressure variation were drawn.The results show that the average velocity of heat transfer of coal seam is 1.57 m/d after 10 d steam injection in the 35 meffective area of thermal stimulation.With the increase of well number and the decrease of well spacing,along the radial direction of well,the well group interference is strengthened,the reservoir pressure drops more quickly,the gas desorption area increases,and the production of well is promoted significantly.The production of cumulative coalbed methane of seven wells heat injection with 20 mwell-bore spacing is 2.01 times of that of five wells with 30 mwell-bore spacing without heat injection.The simulation results show the advantages of heat injection and interwell interference,and provide a theoretical basis for coalbed methane mining technology of multi-well combined with thermal injection in low permeability reservoirs.
引文
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[6]李志强,鲜学福,黄滚.地应力地温场中煤层气富集区高精度定量预测的力学方法[J].煤炭学报,2012,37(S2):395-400.Li Zhiqiang,Xian Xuefu,Huang Gun.High Precision and Quantitative Prediction Mechanics Method of Coalbed Methane Enrichment Area in Geo-Stress and Geothermal Field[J].Journal of China Coal Society,2012,37(Sup.2):395-400.
[7]Wang C,Feng J,Liu J,et al.Direct Observation of Coal-Gas Interactions Under Thermal and Mechanical Loadings[J].International Journal of Coal Geology,2014,131:274-287.
[8]马东民,马薇,蔺亚兵.煤层气解吸滞后特征分析[J].煤炭学报,2012,37(11):1885-1889.Ma Dongmin,Ma Wei,Lin Yabing.Desorption Hysteresis Characteristics of CBM[J].Journal of China Coal Society,2012,37(11):1885-1889.
[9]马东民,张辉,王贵荣,等.胡家河井田煤层气等压吸附/解吸特征研究[J].煤炭科学技术,2016,44(4):119-123.Ma Dongmin,Zhang Hui,Wang Guirong,et al.Study on Isobaric Adsorption/Desorption Features of Coalbed Methane in Hujiahe Coal Field[J].Coal Science and Technology,2016,44(4):119-123.
[10]孟召平,刘珊珊,王保玉,等.不同煤体结构煤的吸附性能及其孔隙结构特征[J].煤炭学报,2015,40(8):1865-1870.Meng Zhaoping,Liu Shanshan,Wang Baoyu,et al.Adsorption Capacity and Its Pore Structure of Coals with Different Coal Body Structure[J].Journal of China Coal Society,2015,40(8):1865-1870.
[11]Shahtalebi A,Khan C,Dmyterko A,et al.Investigation of Thermal Stimulation of Coal Seam Gas Fields for Accelerated Gas Recovery[J].Fuel,2016,180:301-313.
[12]骆祖江.沁水盆地3#煤层气井三维数值模拟研究[J].吉林大学学报(地球科学版),2003,33(4):509-513.Luo Zujiang.Three Dimensional Numerical Simulation of 3#Coal Bed Methane Well in Qinshui Basin[J].Journal of Jilin University(Earth Science Edition),2003,33(4):509-513.
[13]孙可明,潘一山,梁冰.流固耦合作用下深部煤层气井群开采数值模拟[J].岩石力学与工程学报,2007,26(5):994-1001.Sun Keming,Pan Yishan,Liang Bing.Numerical Simulation of Deep Coal-Bed Methane Multi-Well Exploitation Under Fluid-Solid Coupling[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(5):994-1001.
[14]Wang Y,Merry H,Amorer G.Enhance Hydraulic Fracture Coalbed Methane Recovery by Thermal Stimulation[C]//SPE/CSUR Unconventional Resources Conference.Calgary:Society of Petroleum Engineers,2015.
[15]Teng T,Wang J G,Gao F,et al.A Thermally Sensitive Permeability Model for Coal-Gas Interactions Iincluding Thermal Fracturing and Volatilization[J].Journal of Natural Gas Science and Engineering,2016,32:319-333.
[16]杨新乐,任常在,张永利,等.低渗透煤层气注热开采热-流-固耦合数学模型及数值模拟[J].煤炭学报,2013,8(6):1044-1049.Yang Xinle,Ren Changzai,Zhang Yongli,et al.Numerical Simulation of the Coupled ThermalFluid-Solid Mathematical Models During Extracting Methane in Low-Permeability Coal Bed by Heat Injection[J].Journal of China Coal Society,2013,8(6):1044-1049.
[17]张永利,张乐乐,马玉林,等.温度作用下煤层瓦斯解吸渗流规律数值模拟[J].防灾减灾工程学报,2014,34(6):671-677.Zhang Yongli,Zhang Lele,Ma Yulin,et al.Numerical Simulation for Desorption and Seepage Rules of Coal-Bed Methane Considering Temperature Conditions[J].Journal of Disaster Prevention and Mitigation Engineering,2014,34,(6):671-677.
[18]杨新乐.低渗透煤层气注热增产机理的研究[D].阜新:辽宁工程技术大学,2009.Yang Xinle.Study on Mechanism of Injection Heat Increasing Production in Coal-Bed Gas of Low Permeability Coal Seam[D].Fuxin:Liaoning Technical University,2009.
[19]孔祥言.高等渗流力学[M].合肥:中国科学技术大学出版社,1999.Kong Xiangyan.Advanced Mechanics of Fluids in Porous Media[M].Hefei:University of Science and Technology of China Press,1999.
[20]Yang D,Zhao Y S,Hu Y Q.The Constitute Law of Gas Seepage in Rock Fractures Undergoing ThreeDimensional Stress[J].Transport in Porous Media,2006,63(3):463-472.
[21]梁冰,孙可明.低渗透储层煤层气开采理论及其应用[M].北京:科学出版社,2006.Liang Bing,Sun Keming.Theory and Application of Low Permeability Coal Methane Mining[M].Beijing:Science Press,2006.
(1)毫达西(mD)为非法定计量单位,1mD=0.987×10-3μm2,下同。
[2]赵阳升,杨栋,胡耀青,等.低渗透煤储层煤层气开采有效技术途径的研究[J].煤炭学报,2001,26(5):445-458.Zhao Yangsheng,Yang Dong,Hu Yaoqing,et al.Study on the Effective Technology Way for Mining Methane in Low Permeability Coal Seam[J].Journal of China Coal Society,2001,26(5):455-458.
[3]陈晓智,汤达祯,许浩,等.低、中煤阶煤层气地质选区评价体系[J].吉林大学学报(地球科学版),2012,42(增刊2):115-120.Chen Xiaozhi,Tang Dazhen,Xu Hao,et al.Geological Evaluation System of Potential Coalbed Methane Exploration and Development Blocks with Low and Medium Coal Ranks[J].Journal of Jilin University(Earth Science Edition),2012,42(Sup.2):115-120.
[4]程瑞端,鲜学福.温度对煤样渗透系数影响的实验研究[J].煤炭工程师,1998,25(1):13-16.Cheng Ruiduan,Xian Xuefu.Experimental Research on Temperature Effects on the Permeability Coefficient[J].Coal Engineer,1998,25(1):13-16.
[5]李志强,鲜学福,隆晴明.不同温度应力条件下煤体渗透率实验研究[J].中国矿业大学学报,2009,38(4):523-527.Li Zhiqiang,Xian Xuefu,Long Qingming.Experiment Study of Coal Permeability under Different Temperature and Stress[J].Journal of China University of Mining and Technology,2009,38(4):523-527.
[6]李志强,鲜学福,黄滚.地应力地温场中煤层气富集区高精度定量预测的力学方法[J].煤炭学报,2012,37(S2):395-400.Li Zhiqiang,Xian Xuefu,Huang Gun.High Precision and Quantitative Prediction Mechanics Method of Coalbed Methane Enrichment Area in Geo-Stress and Geothermal Field[J].Journal of China Coal Society,2012,37(Sup.2):395-400.
[7]Wang C,Feng J,Liu J,et al.Direct Observation of Coal-Gas Interactions Under Thermal and Mechanical Loadings[J].International Journal of Coal Geology,2014,131:274-287.
[8]马东民,马薇,蔺亚兵.煤层气解吸滞后特征分析[J].煤炭学报,2012,37(11):1885-1889.Ma Dongmin,Ma Wei,Lin Yabing.Desorption Hysteresis Characteristics of CBM[J].Journal of China Coal Society,2012,37(11):1885-1889.
[9]马东民,张辉,王贵荣,等.胡家河井田煤层气等压吸附/解吸特征研究[J].煤炭科学技术,2016,44(4):119-123.Ma Dongmin,Zhang Hui,Wang Guirong,et al.Study on Isobaric Adsorption/Desorption Features of Coalbed Methane in Hujiahe Coal Field[J].Coal Science and Technology,2016,44(4):119-123.
[10]孟召平,刘珊珊,王保玉,等.不同煤体结构煤的吸附性能及其孔隙结构特征[J].煤炭学报,2015,40(8):1865-1870.Meng Zhaoping,Liu Shanshan,Wang Baoyu,et al.Adsorption Capacity and Its Pore Structure of Coals with Different Coal Body Structure[J].Journal of China Coal Society,2015,40(8):1865-1870.
[11]Shahtalebi A,Khan C,Dmyterko A,et al.Investigation of Thermal Stimulation of Coal Seam Gas Fields for Accelerated Gas Recovery[J].Fuel,2016,180:301-313.
[12]骆祖江.沁水盆地3#煤层气井三维数值模拟研究[J].吉林大学学报(地球科学版),2003,33(4):509-513.Luo Zujiang.Three Dimensional Numerical Simulation of 3#Coal Bed Methane Well in Qinshui Basin[J].Journal of Jilin University(Earth Science Edition),2003,33(4):509-513.
[13]孙可明,潘一山,梁冰.流固耦合作用下深部煤层气井群开采数值模拟[J].岩石力学与工程学报,2007,26(5):994-1001.Sun Keming,Pan Yishan,Liang Bing.Numerical Simulation of Deep Coal-Bed Methane Multi-Well Exploitation Under Fluid-Solid Coupling[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(5):994-1001.
[14]Wang Y,Merry H,Amorer G.Enhance Hydraulic Fracture Coalbed Methane Recovery by Thermal Stimulation[C]//SPE/CSUR Unconventional Resources Conference.Calgary:Society of Petroleum Engineers,2015.
[15]Teng T,Wang J G,Gao F,et al.A Thermally Sensitive Permeability Model for Coal-Gas Interactions Iincluding Thermal Fracturing and Volatilization[J].Journal of Natural Gas Science and Engineering,2016,32:319-333.
[16]杨新乐,任常在,张永利,等.低渗透煤层气注热开采热-流-固耦合数学模型及数值模拟[J].煤炭学报,2013,8(6):1044-1049.Yang Xinle,Ren Changzai,Zhang Yongli,et al.Numerical Simulation of the Coupled ThermalFluid-Solid Mathematical Models During Extracting Methane in Low-Permeability Coal Bed by Heat Injection[J].Journal of China Coal Society,2013,8(6):1044-1049.
[17]张永利,张乐乐,马玉林,等.温度作用下煤层瓦斯解吸渗流规律数值模拟[J].防灾减灾工程学报,2014,34(6):671-677.Zhang Yongli,Zhang Lele,Ma Yulin,et al.Numerical Simulation for Desorption and Seepage Rules of Coal-Bed Methane Considering Temperature Conditions[J].Journal of Disaster Prevention and Mitigation Engineering,2014,34,(6):671-677.
[18]杨新乐.低渗透煤层气注热增产机理的研究[D].阜新:辽宁工程技术大学,2009.Yang Xinle.Study on Mechanism of Injection Heat Increasing Production in Coal-Bed Gas of Low Permeability Coal Seam[D].Fuxin:Liaoning Technical University,2009.
[19]孔祥言.高等渗流力学[M].合肥:中国科学技术大学出版社,1999.Kong Xiangyan.Advanced Mechanics of Fluids in Porous Media[M].Hefei:University of Science and Technology of China Press,1999.
[20]Yang D,Zhao Y S,Hu Y Q.The Constitute Law of Gas Seepage in Rock Fractures Undergoing ThreeDimensional Stress[J].Transport in Porous Media,2006,63(3):463-472.
[21]梁冰,孙可明.低渗透储层煤层气开采理论及其应用[M].北京:科学出版社,2006.Liang Bing,Sun Keming.Theory and Application of Low Permeability Coal Methane Mining[M].Beijing:Science Press,2006.
(1)毫达西(mD)为非法定计量单位,1mD=0.987×10-3μm2,下同。