辽宁矿区煤层气开采渗流规律研究
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摘要
煤层气是一种可替代天然气的高效、洁净能源,具有广阔的开发前景。我国部分地区的煤层气资源已形成产业化,辽宁煤层气资源量丰富,虽然开发起步早,也取得了很大的成功,但尚未形成全面产业化。其主要原因在于煤层大多数为低渗透煤层,大部分煤层含水,在钻井采气过程中伴随着水的产出,而水的存在影响了煤层气的产出。从文献的检索情况来看,辽宁各煤层气开采井渗流规律的系统分析较少。本论文采用实验室实验与数值模拟结合的研究方法,对考虑滑脱效应的水-气两相流的渗流机理、影响因素、数学模型等进行了进一步的研究,通过实验室实验发现,同一煤样的渗透率均随围压的增加而降低,且在围压较高时,煤样只有获得足够大的压力梯度时,才能使煤样具有一定的渗透性,且渗流曲线几乎都呈V字型变化。当围压相同时,不同含水率下的渗透率随着束缚水饱和度的增加而减小,气体通过同一煤样的启动压力逐渐增大,表现出与线性阶段围压增加相同的效果。在考虑滑脱效应影响时,通过实验拟合结果可以看出滑脱效应与达西渗流是同时存在的,实验过程中,在孔隙压较低时,滑脱效应为主要的渗流方式。而随着孔隙压的增加,有效应力降低,达西渗流方式开始增长,滑脱效应开始减小,当到达极值点时,达西渗流开始迅速增加,滑脱渗流方式减缓。通过建立的数学模型,在给出基本假设后,应用FEPG软件对考虑滑脱效应和不考虑滑脱效应煤层气渗透率、储层压力进行对比研究。其结果表明:在井周附近,考虑滑脱效应的压力要比不考虑滑脱效应的压力大,影响压力分布的区域也比不考虑滑脱效应的范围大。达西流和滑脱流靠近生产井周的区域压力变化都比远端剧烈;达西流对压力影响的范围比滑脱流小,压力梯度比滑脱流大。而通过实验样品参数进行煤层储层的压力、浓度、含水率、相对渗透率及井田水、气排采数据与现场数据对比分析可以看出,其模拟结果与现场实测排采数据吻合性较好。可为今后开采低渗气藏提供科学依据及产能预测。
CBM is efficient and clean energy in place of natural gas,it has the broad development prospects. Some areas of our country have already formed the industrialization of coalbed methane resources, Liaoning CBM resources are abundant, although development started early, and achieved great success, but not yet formed a comprehensive industrialization. The main reason is that the majority of coal seams are low-permeability and contain water, gas output goes with water output in the process of drilling, while water affects the coalbed methane's output. From the retrieval, seepage rule system analyses of Liaoning mine CBM exploration is lesser. By combining laboratory test with the numerical simulation, further research in consideration of the slippage effect of water-gas two-phase percolation mechanism, influencing factors and mathematical model are made, found by the laboratory tests: the permeability of the same coal samples decrease with the increase of confining pressure, and in high confining pressure, coal sample can have certain permeability only getting enough pressure gradient,seepage curves are almost V shape. When the same confining pressure,permeability decrease with the increase of irreducible water saturation under different water content, the gas through the same coal sample start-up pressure increase gradually, that show up the same effect of the linear phase confining pressure increase.When considering slippage effect’s influence, through the experiment fitting results can found that slippage effect and darcy seepage exist simultaneously, during the test, when pore pressure is lower, slippage effect is the main seepage mode. With the increase of pore pressure,effective stress reduces, darcy seepage approaches to grow, slippage effect begins to decrease, When pore pressure reach to the extreme value point, darcy seepage began to increase rapidly, slippage effect mode slow down.. Through the established mathematical model and the given basic assumptions,CBM permeability and reservoir pressure of considering slippage effect and without considering slippage effect are comparatively studied by FEPG software. The results show that the pressure near wells in consideration of slippage effect is higher than that without considering of slippage effect, distribution area of the effect pressure also bigger than that without considering of slippage effect. Regional stress of darcy flow and slippage effect near the production wells change acutely than that of distal area, the influence to pressure of Darcy flow is lower than slippage effect flow’s,and pressure gradient is higher than slippage effect flow. Through contrastive analysis of the laboratory test sample parameters of coal reservoir pressure, concentration, moisture content, the relative permeability and drainage date and field data analysis can found that the simulation results and the field measured data are consistent. The result could provide scientific basis and productivity prediction for the exploitation of low permeability gas reservoirs.
CBM is efficient and clean energy in place of natural gas,it has the broad development prospects. Some areas of our country have already formed the industrialization of coalbed methane resources, Liaoning CBM resources are abundant, although development started early, and achieved great success, but not yet formed a comprehensive industrialization. The main reason is that the majority of coal seams are low-permeability and contain water, gas output goes with water output in the process of drilling, while water affects the coalbed methane's output. From the retrieval, seepage rule system analyses of Liaoning mine CBM exploration is lesser. By combining laboratory test with the numerical simulation, further research in consideration of the slippage effect of water-gas two-phase percolation mechanism, influencing factors and mathematical model are made, found by the laboratory tests: the permeability of the same coal samples decrease with the increase of confining pressure, and in high confining pressure, coal sample can have certain permeability only getting enough pressure gradient,seepage curves are almost V shape. When the same confining pressure,permeability decrease with the increase of irreducible water saturation under different water content, the gas through the same coal sample start-up pressure increase gradually, that show up the same effect of the linear phase confining pressure increase.When considering slippage effect’s influence, through the experiment fitting results can found that slippage effect and darcy seepage exist simultaneously, during the test, when pore pressure is lower, slippage effect is the main seepage mode. With the increase of pore pressure,effective stress reduces, darcy seepage approaches to grow, slippage effect begins to decrease, When pore pressure reach to the extreme value point, darcy seepage began to increase rapidly, slippage effect mode slow down.. Through the established mathematical model and the given basic assumptions,CBM permeability and reservoir pressure of considering slippage effect and without considering slippage effect are comparatively studied by FEPG software. The results show that the pressure near wells in consideration of slippage effect is higher than that without considering of slippage effect, distribution area of the effect pressure also bigger than that without considering of slippage effect. Regional stress of darcy flow and slippage effect near the production wells change acutely than that of distal area, the influence to pressure of Darcy flow is lower than slippage effect flow’s,and pressure gradient is higher than slippage effect flow. Through contrastive analysis of the laboratory test sample parameters of coal reservoir pressure, concentration, moisture content, the relative permeability and drainage date and field data analysis can found that the simulation results and the field measured data are consistent. The result could provide scientific basis and productivity prediction for the exploitation of low permeability gas reservoirs.
引文
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[4]张志刚.井下煤层气抽采产能预测模型研究[D].2008,04
[5]余楚新,鲜学福,谭学术.煤层瓦斯流动理论及渗流控制方程的研究[J].重庆大学学报(自然科学版),1989,12(5):1-9
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[7]余楚新.煤层中瓦斯富集、运移的基础与应用研究[D].重庆:重庆大学,1993
[8] Sun Peide.Coal gas dynamics and its applications.Scientia Geologica Sinica,1994,3(1)
[9]孙培德.煤层瓦斯流场流动规律的研究[J].煤炭学报,1987,12(4):74-82
[10]王晓亮.煤层瓦斯流动理论模拟研究[D].太原理工大学,2003
[11]郭勇义,周世宁.煤层瓦斯一维流场流动规律的完全解[J].中国矿业学院学报,1984,2(2):19-28
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[13]周世宁,何学秋.煤和瓦斯突出机理的流变假说[J].中国矿业大学学报,1990.05
[14]周世宁.瓦斯在煤层中流动的机理[J].煤炭学报,1990,15(1):61-67
[15]周世宁.煤层瓦斯运动理论分析[J].北京矿业学院学报,1957.03
[16]周世宁.电子计算机在研究煤层瓦斯流动理论中的应用[J].煤炭学报,1983. 7(2)
[17]林柏泉,周世宁.煤样瓦斯渗透率的实际研究[J].中国矿业大学学报,1987(1)
[18]姚宇平,周世宁.含瓦斯煤的力学性质[J].中国矿业大学学报,1988(1)
[19]程瑞端.煤层瓦斯涌出规律及其深部开采预测的研究[D].重庆:重庆大学,1995
[20]张广洋.煤结构与煤的瓦斯吸附、渗流特性研究[D].重庆:重庆大学,1995
[21]张广洋,谭学术.煤层瓦斯运移的数学模型[J].重庆大学学报,1994.7(4):53-57
[22]谭学术,鲜学福等.复合岩体力学理论及其应用[M].北京:煤炭工业出版社,1994
[23]谭学术,袁静.矿井煤层真实瓦斯渗流方程的研究[J].重庆建筑工程学院学报,1986.04
[24]肖勤学,吴泽源,谭学术.煤层瓦斯渗流方程及其在瓦斯抽放中的应用[J].重庆大学学报(自然科学版),1986.05
[25]黄运飞,孙广忠.煤—瓦斯介质力学[M].北京煤炭工业出版社会.1993
[26]孙培德.煤层瓦斯动力学的基本模型[J].西安矿业学院学报,1987.07
[132]冯增朝.低渗透煤层瓦斯强化抽采理论及应用[M].北京:科学出版社,2008年7月
[133]周世宁,林柏泉.煤层瓦斯赋存与流动理论[M].北京:煤炭工业出版社,1999年2月
[134]阜新矿业(集团)有限责任公司.辽宁省阜新市刘家区煤层气储量报告.2006年3月
[135]刘曰武,张大为,陈慧新,宫欣.多井条件下煤层气不定常渗流问题的数值研究.岩石力学与工程学报,2005年5月,Vb1.24 No.10,
[136]麻翠杰,郭大浩,邓英尔,黄润秋,刘慈群.致密煤层气运移的数值模拟.大庆石油学院学报,005年6月,Vo1.29 No.3。
[137] Sohei,SHIMADA,Takeshi,TAKAHASHI.Effectiveness of Horizontal Wells in Enhanced Coalbed Methane Recovery.The 6th International Workshop on CBM/CMM in China,2006-11-10.
[138] Huainan Mining Group.Speeding up Utilization of CBM/CMM for Realizing Green Coal Extraction . The 6th International Workshop on CBM/CMM in China,2006-11-10.
[139] Christiaan Vrolijk Carbon Resource Managemen.Clean Development with CBM/CMM.The 6th International Workshop on CBM/CMM in China, 2006-11-10.
[140]肖晓春,潘一山.考虑滑脱效应的煤层气渗流数学模型及数值模拟[J].岩石力学与工程学报,2005年8月:2966-2970
[141]肖晓春,潘一山.滑脱效应影响的低渗煤层气运移实验研究[J].岩土工程学报,2009年10月:1554-1558
[142]肖晓春,潘一山.考虑滑脱效应的水气耦合煤层气渗流数值模拟[J].煤炭学报,2006年12月:711-715
[143]彭晓华,肖晓春,潘一山.FEPG在煤层气渗流规律研究中的应用[J].辽宁工程技术大学学报自然科学版,2008年6月:
[144]Peng xiao-hua,Pan yi-shan,Xiao xiao-chun.The experiment study on slippage effect of the coal-bed methane transfusion[J].JOURNAL OF COAL SCIENCE & ENGINEERING(CHINA),Dec.2008:530-533
[2]孙培德,鲜学福,茹宝麒.煤层瓦斯渗流力学研究现状和展望[J].煤炭工程师,1996,3:23-34
[3]陶云奇,许江,李树春,彭守建.煤层瓦斯渗流特性研究进展[J].2009,04:1-5
[4]张志刚.井下煤层气抽采产能预测模型研究[D].2008,04
[5]余楚新,鲜学福,谭学术.煤层瓦斯流动理论及渗流控制方程的研究[J].重庆大学学报(自然科学版),1989,12(5):1-9
[6]鲜学福等.地电场对煤层中瓦斯渗流影响的研究[R].国家自然科学基金资助项目研究总结报告.重庆大学,1993
[7]余楚新.煤层中瓦斯富集、运移的基础与应用研究[D].重庆:重庆大学,1993
[8] Sun Peide.Coal gas dynamics and its applications.Scientia Geologica Sinica,1994,3(1)
[9]孙培德.煤层瓦斯流场流动规律的研究[J].煤炭学报,1987,12(4):74-82
[10]王晓亮.煤层瓦斯流动理论模拟研究[D].太原理工大学,2003
[11]郭勇义,周世宁.煤层瓦斯一维流场流动规律的完全解[J].中国矿业学院学报,1984,2(2):19-28
[12]周世宁,孙辑正.煤层瓦斯流动理论及其应用[J].煤炭学报,1965,2(1):24-36
[13]周世宁,何学秋.煤和瓦斯突出机理的流变假说[J].中国矿业大学学报,1990.05
[14]周世宁.瓦斯在煤层中流动的机理[J].煤炭学报,1990,15(1):61-67
[15]周世宁.煤层瓦斯运动理论分析[J].北京矿业学院学报,1957.03
[16]周世宁.电子计算机在研究煤层瓦斯流动理论中的应用[J].煤炭学报,1983. 7(2)
[17]林柏泉,周世宁.煤样瓦斯渗透率的实际研究[J].中国矿业大学学报,1987(1)
[18]姚宇平,周世宁.含瓦斯煤的力学性质[J].中国矿业大学学报,1988(1)
[19]程瑞端.煤层瓦斯涌出规律及其深部开采预测的研究[D].重庆:重庆大学,1995
[20]张广洋.煤结构与煤的瓦斯吸附、渗流特性研究[D].重庆:重庆大学,1995
[21]张广洋,谭学术.煤层瓦斯运移的数学模型[J].重庆大学学报,1994.7(4):53-57
[22]谭学术,鲜学福等.复合岩体力学理论及其应用[M].北京:煤炭工业出版社,1994
[23]谭学术,袁静.矿井煤层真实瓦斯渗流方程的研究[J].重庆建筑工程学院学报,1986.04
[24]肖勤学,吴泽源,谭学术.煤层瓦斯渗流方程及其在瓦斯抽放中的应用[J].重庆大学学报(自然科学版),1986.05
[25]黄运飞,孙广忠.煤—瓦斯介质力学[M].北京煤炭工业出版社会.1993
[26]孙培德.煤层瓦斯动力学的基本模型[J].西安矿业学院学报,1987.07
[132]冯增朝.低渗透煤层瓦斯强化抽采理论及应用[M].北京:科学出版社,2008年7月
[133]周世宁,林柏泉.煤层瓦斯赋存与流动理论[M].北京:煤炭工业出版社,1999年2月
[134]阜新矿业(集团)有限责任公司.辽宁省阜新市刘家区煤层气储量报告.2006年3月
[135]刘曰武,张大为,陈慧新,宫欣.多井条件下煤层气不定常渗流问题的数值研究.岩石力学与工程学报,2005年5月,Vb1.24 No.10,
[136]麻翠杰,郭大浩,邓英尔,黄润秋,刘慈群.致密煤层气运移的数值模拟.大庆石油学院学报,005年6月,Vo1.29 No.3。
[137] Sohei,SHIMADA,Takeshi,TAKAHASHI.Effectiveness of Horizontal Wells in Enhanced Coalbed Methane Recovery.The 6th International Workshop on CBM/CMM in China,2006-11-10.
[138] Huainan Mining Group.Speeding up Utilization of CBM/CMM for Realizing Green Coal Extraction . The 6th International Workshop on CBM/CMM in China,2006-11-10.
[139] Christiaan Vrolijk Carbon Resource Managemen.Clean Development with CBM/CMM.The 6th International Workshop on CBM/CMM in China, 2006-11-10.
[140]肖晓春,潘一山.考虑滑脱效应的煤层气渗流数学模型及数值模拟[J].岩石力学与工程学报,2005年8月:2966-2970
[141]肖晓春,潘一山.滑脱效应影响的低渗煤层气运移实验研究[J].岩土工程学报,2009年10月:1554-1558
[142]肖晓春,潘一山.考虑滑脱效应的水气耦合煤层气渗流数值模拟[J].煤炭学报,2006年12月:711-715
[143]彭晓华,肖晓春,潘一山.FEPG在煤层气渗流规律研究中的应用[J].辽宁工程技术大学学报自然科学版,2008年6月:
[144]Peng xiao-hua,Pan yi-shan,Xiao xiao-chun.The experiment study on slippage effect of the coal-bed methane transfusion[J].JOURNAL OF COAL SCIENCE & ENGINEERING(CHINA),Dec.2008:530-533
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