宁武盆地煤岩静态力学特征研究

第42卷第6期煤田地质与勘探Vol.42No.62014年12月COALGEOLOGY&EXPLORATIONDec.2014收稿日期:2013-08-02基金项目:(2011ZX05021)作者简介:(1980).文章编号:1001-1986(2014)06-0050-05宁武盆地煤岩静态力学特征研究林海1，张宇1，程远方2，陈磊1，郑玉辉1，张振活1，凡帆1，董海东1，涂海海1(1.低渗透油气田勘探开发国家工程实验室，川庆钻探钻采工程技术研究院，陕西西安710018；2.中国石油大学(华东)石油工程学院，山东青岛266580):井壁失稳是目前制约煤层气规模化开发的关键问题之一。由岩石力学理论可知，煤岩的力学强度是井壁稳定性的决定因素之一。通过对宁武盆地煤岩进行系统力学研究，利用应力摩尔圆法求出宁武盆地主力煤岩的内摩擦角、内聚力等强度参数；建立横波与纵波幂律关系曲线，动态弹性模量与静态弹性模量间线性关系曲线及动静态泊松比间线性关系曲线，得出煤岩静态弹性参数以直接反应地层力学性质，解决了勘探开发中声波测井所得动态弹性参数无法真实反映地层力学特点的技术问题。：宁武盆地；煤层气；静态弹性参数；力学特征；煤岩软化性：TE371：ADOI:10.3969/j.issn.1001-1986.2014.06.010ThestaticmechanicscharacteristicsinNingwubasinLINHai1,ZHANGYu1,CHENGYuanfang2,CHENLei1,ZHENGYuhui1,ZHANGZhenhuo1,FANFan1,DONGHaidong1,TUHaihai1(1.NationalEngineeringLaboratoryforExplorationandDevelopmentofLowPermeabilityOilandGasField,ChuanqingDrillingandproductionEngineeringandtechnologyResearchInstitute,Xi′an710018,China;2.DepartmentofPetroleumEngineering,UniversityofPetroleum(EastChina),Qingdao266580,China)Abstract:HowtodeveloptherichCBMresourcenowbecomesanimportantprojectinChina.Thewellboreinsta-bilityisakeyfactorrestrictingCBMeconomicaldevelopment.Accordingtorockmechanicsthemechanicalcharac-teristicsofcoalbediscriticalfactorforCBMwellborestability,thestudyofthestaticmechanicalcharacteristicshasonlydevelopedinalimitedlevelinChinarecently,thispapermakesthesystematicstudyonthemechanicsofcoalbedinNingwubasin,gottheextensionandcompressivestrength,calculatedtheinternalfrictionangleandthecohesion,builtthepowerlawrelationshipforlongitudinalwaveandtransversewaveandalsofoundoutthelinearrelationbetweendynamicelasticparametersandstaticelasticparameters.Itgivesatechnicalmethodonhowtogetmechanicscharacteristicsofformationonthebasisofdynamicelasticparametersobtainedfromacousticlogging.Keywords:Ningwubasin;coalbedmethane(CBM);staticelasticparameter;mechanicscharacteristics;softingpropertyofcoal[1-2]()[3][4][5-6]1宁武盆地煤层气概况NNE130km20~30km第6期林海等:宁武盆地煤岩静态力学特征研究·51·3120km2—920m12m413.15m3.0~6.0m911.7~20.3m3/t300~1500m876.0km2[7-9]2煤岩力学实验2.1202PR3905EDC25W10WT1002.2()[10]ubt2πPDt(1)PuDt(1)120.8r()649141.077MPa91.219MPa表1单轴抗拉强度实验结果Table1Uniaxialtensilestrengthtestresults/mm/mm/MPa/MPa/MPa4-116.4024.40.61.2004-216.0024.120.450.9334-315.0024.240.501.1001.0779-114.6424.440.611.3649-216.8824.420.631.2239-316.3224.520.701.2791.2192.3(2)ccPA(2)cPcA表2单轴抗压强度实验结果Table2Theuniaxialcompressivestrengthtestresults/MPa/MPa4-3-420.904-3-719.604-3-820.4820.339-7-426.629-7-727.919-7-927.4827.342.4σ3σ1σ1σ3σ–τσ3σ1σ1σ3–·52·煤田地质与勘探第42卷0ntgf(3)tgf(4)fτ0σnfασ–τ–11–Fig.1Mohr-Coulombfailurecriterion618–(3)表3岩心的三轴抗压强度实验结果Table3Triaxialcompressivestrengthtestresults/MPa/MPa/GPa4-4-1331.883.980.2224-4-2537.954.150.28914-4-4743.404.260.3164-6-1335.954.120.2084-6-2542.935.540.30324-6-3748.547.080.3244-6-2335.124.050.2754-6-3539.975.830.33834-6-1746.547.360.3659-2-1852.773.080.2109-2-21059.694.330.32849-2-31263.896.810.3569-3-1854.293.560.2179-3-21060.014.660.33159-3-41266.816.320.3549-4-1863.793.210.2449-4-31068.934.350.34269-4-21274.896.410.359345MPa4000~6000MPa0.28~0.34910MPa4000~5000MPa0.32~0.342.544947.40MPa39.64°9.98MPa35.73°表4岩心的内聚力和内摩擦角Table4Thecohesionandinternalfrictionangle/MPa/(°)/MPa/(°)16.8838.9827.5441.1837.7738.767.4039.6449.2938.0958.2231.05612.4438.059.9835.732.6–2psd2ps0.5/1/1VVVV(5)第6期林海等:宁武盆地煤岩静态力学特征研究·53·222sps3d22ps3410VVVEVV(6)dEdMPaVpm/sVsm/sg/cm345表5煤层声波实验结果Table5Theacousticwavetestresultsforcoal/MPa/kN/(m·s–1)/(m·s–1)/GPa13231.371820.9915.100.267323433.331883.4316.370.28523433.331883.4316.370.28552.53433.331894.2516.510.28123506.381894.2516.680.2944-1733506.381894.2516.680.29412681.251276.007.640.354322681.251276.007.640.35422818.111280.607.790.37052.52813.111280.607.780.36922813.111295.097.940.3664-2732813.111295.097.940.36622405.451199.635.090.334832405.481211.005.170.33022405.481211.005.170.330103.52438.891211.005.190.33632438.891211.005.190.3369-11242438.891211.005.190.33622564.101198.005.200.360832597.401187.005.130.36822597.401187.005.130.368103.52631.581187.005.150.37232631.581187.005.150.3729-21242631.581187.005.150.3722×2Fig.2Relationbetweenshearwavevelocityandacousticimpedance0.7702sp2.1751()VV(7)(5)(6)5(35)(34)3Fig.3Relationbetweendynamicelasticmodulusandstaticelasticmodulus4Fig.4Relationbetweendynamicpoisson'sratioandstaticpoisson'sratio2.7XX49·54·煤田地质与勘探第42卷8(4)X6表64号和9号煤矿物分析结果Table6Themineralanalysisresults%4-1928…………4-27327…………4-570252………4-678202……39-29010……29-3835…759-4953…2…9-8913……149492.81[11](3MPa)12h24h36h420.33MPa36h17.54MPa13.72%927.34MPa36h24.27MPa11.23%436h30.5%36h10.92%936h8.21%36h0.25%3结论a.b.c.参考文献[1].[J].201133(3)74–77.[2].[J].20074(1)26–31.[3].–[J].1998(2)18–19.[4].[J].20118(6)37–41.[5].[J].200724(4)28–29.[6].[J].201038(3)1–7.[7].[M].2006.[8].[J].200828(3)93–95.[9].[M].2003.[10].[M].1993.[11].[M].2006.