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| MATHEMATICAL MODEL OF EFFECTIVE STRESS OF COAL RESERVOIR BASED ON DAMAGE MECHANICS |
| NI Xiaoming1，2，ZHANG Chongchong1，WANG Yanbin3，WANG Xianghao3 |
| (1. School of Energy Science and Engineering，Henan Polytechnic University，Jiaozuo，Henan 454000，China；2. State Key Laboratory Cultivation Base for Gas Geology and Gas Control，Henan Polytechnic University，Jiaozuo，Henan 454000，China；3. College of Geoscience and Surveying Engineering，China University of Mining and Technology，Beijing 100083，China) |
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Abstract In order to accurately determine the stress of coal matrix in different coal reservoir properties and different surrounding rock stress conditions，the stress mathematical model of coal matrix by fully considering the coupling effects among the solid，liquid and gas in reservoir was established. Considering the compositions of internal material of the coal reservoir，the coal reservoir geometry concept model was established based on the spherical pore structure. Combined with the elastoplastic mechanics theory，the mathematical model about the effective stress coefficient was gained. Considering the damage evolution processes of coal total stress and pore stress with damage mechanics theory，the effective stress mathematical model of coal reservoir matrix was established. Taking the original reservoir parameters in Fanzhuang block for example，the effective stress changing laws were gained in different reservoir parameters：the effective stress is larger influenced by porosity and gas saturation. When other conditions are the same，with increasing of porosity or gas saturation，the stress of the coal matrix is exponentially decreasing. However，the influence of porosity is more intense than that of the gas saturation，the exponential relation curve between effective stress and gas saturation is more obvious than the porosity. The distributions of pores size and stresses are different. Under the same porosity conditions，with the increase of proportion of the biggest holes，it is logarithmic reduction. The effective stress is linearly reduced with water saturation increases.
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Received: 24 December 2012
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| [1] TERZAGHI K. Theoretical soil mechanics[M]. New York：John Wiley and Sons，Inc.，1943：11–15.
[2] 吴世跃，赵 文. 含吸附煤层气煤的有效应力分析[J]. 岩石力学与工程学报，2005，24(10)：1 674–1 678.(WU Shiyue，ZHAO Wen. Effective stress analysis on adsorbed coal[J]. Chinese Journal of Rock Mechanics and Engineering，2005，24(10)：1 674–1 675.(in Chinese))
[3] 李丽君，李 闽，向祖平，等. 低渗气藏岩石渗透率有效应力系数研究[J]. 重庆科技学院学报，2010，12(6)：79–82.(LI Lijun，LI Min，XIANG Zuping，et al. The effective stress coefficient of low permeability gas reservoir rock permeability[J]. Journal of Chongqing University of Science and Technology，2010，12(6)：79–82.(in Chinese))
[4] 陶云奇，许 江，彭守建，等. 含瓦斯煤孔隙率和有效应力影响因素试验研究[J]. 岩土力学，2010，31(11)：3 417–3 422.(TAO Yunqi，XU Jiang，PENG Shoujian，et al. Experimental research on affecting factors of coal containing gas porosity and effective stress[J]. Rock and soil mechanics，2010，31(11)：3 417–3 422.(in Chinese))
[5] ENEVER J R E，HENNING A. The relationship between permeability and effective stress for Australian coal and its implications with respect to coalbed methane exploration and reservoir model[C]// Proceedings of the 1997 International Coal-bed Methane Symposium. Tuscaloosa：[s.n.]，1997：13–22.
[6] 张 凯，周 辉，胡大伟，等. 弹塑性条件下岩土孔隙介质有效应力系数理论模型[J]. 岩土力学，2010，31(4)：1 035–1 041.(ZHANG Kai，ZHOU Hui，HU Dawei，et al. Theoretical model of effective stress coefficient of elastoplastic rock porous media[J]. Rock and Soil Mechanics，2010，31(4)：1 035–1 041.(in Chinese))
[7] 李 闵，肖文联. 低渗砂岩储层渗透率有效应力定律试验研究[J]. 岩石力学与工程学报，2006，25(8)：1 563–1 568. (LI Min，XIAO Wenlian. The experimental study on low permeability sandstone reservoir permeability effective stress law[J]. Chinese Journal of Rock Mechanics and Engineering，2006，25(8)：1 563–1 568.(in Chinese))
[8] 蔡新树，陈 勉，金 衍，等. 各向异性多重孔隙介质有效应力定律[J]. 工程力学，2009，26(4)：57–60.(CAI Xinshu，CHEN Mian，JIN Yan，et al. The effective stress law of anisotropic multiple porous media[J]. Engineering Mechanics，2009，26(4)：57–60.(in Chinese))
[9] 闫 铁，李 玮，毕雪亮. 基于分形方法的多孔介质有效应力模型研究[J]. 岩土力学，2010，31(8)：2 625–2 629. (YAN Tie，LI Wei，BI Xueliang.The effective stresses of porous media model research based on fractal method[J]. Rock and Soil Mechanics，2010，31(8)：2 625–2 629.(in Chinese))
[10] 介玉新，温庆博，李广信，等. 有效应力原理几个问题探讨[J]. 煤炭学报，2005，30(2)：202–205.(JIE Yuxin，WEN Qinbo，LI Guangxin，et al. Discussion on the principle of effective stress[J]. Journal of China Coal Society，2005，30(2)：202–205.(in Chinese))
[11] 赵成刚，蔡国庆. 非饱和土广义有效应力原理[J]. 岩土力学，2009，30(11)：3 232–3 236.(ZHAO Chenggang，CAI Guoqing. The principle of generalized effective stress for unsaturated soil[J]. Rock and Soil Mechanics，2009，30(11)：3 232–3 236.(in Chinese))
[12] 陈俞炯. 有效应力原理对饱和黏土的适用性[J]. 岩土工程学报，2011，33(6)：985–989.(CHEN Yujiong. The applicability of principle of effective stress for unsaturated clay[J]. Chinese Journal of Geotechnical Engineering，2011，33(6)：985–989.(in Chinese))
[13] WARRENH J E，ROOT P J. The behavior of naturally fractured reservoirs[J]. Society of Petroleum Engineers Journal，1963，3(3)：245–255.
[14] 曲焱喆，盖秉政. 多孔有限弹性平面问题的研究[J]. 哈尔滨工业大学学报，2008，40(3)：358–362.(QU Yanzhe，GAI Bingzheng. Study on the plane problem of elastic porous Co[J]. Journal of Harbin Institute of Technology，2008，40(3)：358–362.(in Chinese))
[15] 高延法，张劲松. 矿山岩体力学[M]. 北京：中国矿业大学出版社，2000：36–40.(GAO Yanfa，ZHANG Jinsong. Mines rock mass mechanics[M]. Beijing：China University of Mining and Technology Press，2000：36–40.(in Chinese)) |
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2014, Vol. 33 
