【保德区块煤层气特征及成因分析案例1900字】

致谢保德区块煤层气特征及成因分析案例目录TOC\o"1-3"\h\u9114保德区块煤层气特征及成因分析案例 33147061.1煤层气组分特征 337671.2煤层气成因 35151141.2.1甲烷碳同位素成因 35294441.2.2二氧化碳同位素成因 36煤层气地球化学特征是反映煤层气成因及赋存条件的重要参数，目前广泛使用煤层气组分、煤层气中的甲烷碳氢同位素、二氧化碳同位素特征来区分煤层气成因ADDINEN.CITEADDINEN.CITE.DATA[10,21]。但是，煤层的甲烷碳同位素比常规天然气更复杂ADDINEN.CITEADDINEN.CITE.DATA[22-24],而且受到更多因素的影响ADDINEN.CITEADDINEN.CITE.DATA[25-29]。本部分以同位素的测试数据为依据，分析了保德地区煤层气组分特征，并结合甲烷与二氧化碳成因图版，对研究区4+5#煤煤层气和8+9#煤煤层气的煤层气甲烷及二氧化碳成因进行了分析与判别。1.1煤层气组分特征煤矿采掘面的煤岩解吸气组分变化较大，其次为煤矿抽放气和钻井煤心解吸气ADDINEN.CITE<EndNote><Cite><Author>李勇</Author><Year>2015</Year><RecNum>522</RecNum><DisplayText><styleface="superscript">[30]</style></DisplayText><record><rec-number>522</rec-number><foreign-keys><keyapp="EN"db-id="90ax0pf5fw2fxlewxs9p0dsd09sravx9vfff"timestamp="1617895921">522</key></foreign-keys><ref-typename="Thesis">32</ref-type><contributors><authors><author>李勇</author></authors><tertiary-authors><author>汤达祯,</author></tertiary-authors></contributors><titles><title>鄂尔多斯盆地东缘煤层气富集成藏规律研究</title></titles><keywords><keyword>鄂尔多斯盆地东缘</keyword><keyword>煤层气成藏</keyword><keyword>煤层气成因</keyword><keyword>煤储层物性</keyword><keyword>成藏控制因素</keyword></keywords><dates><year>2015</year></dates><publisher>中国地质大学(北京)</publisher><work-type>博士</work-type><urls></urls><remote-database-provider>Cnki</remote-database-provider></record></Cite></EndNote>[30]，排采气的组分变化最小ADDINEN.CITEADDINEN.CITE.DATA[21,31]。对研究区4+5#煤层以及8+9#煤层不同深度下产出气体样品进行了气组分分析，并开展了碳氢同位素测试，得到的实验结果如表4-1所示：表3-1煤层气组分及同位素测试结果煤层编号样品编号采样深度/m煤层气组分体积分数/%δ13C/‰δD/‰CO2N2CH4CH4CO28+9B1-68-3B1-68-4B2-46-3B2-46-4B2-46-5B2-46-6B2-46-7546.54-546.84546.84-547.201061.10-1061.401064.00-1064.351065.60-1066.001066.80-1067.101068.00-1068.304.381.028.9910.7810.3211.168.394.079.412.611.821.612.241.5491.5687.5888.2087.2587.6884.4186.78-61.8-61.4-51.1-51.4-51.2-51.4-50.7-9.8-10.51.65.455.35-259.4-259.3-250.9-249.4-250.4-249.2-248.6平均8.151.3387.64-54.10.57-252.54+5B1-68-1B1-68-2B2-46-1B2-46-2501.40-501.70502.90-501.301011.40-1011.701012.40-1012.702.991.251.681.057.3811.791.256.3389.6084.9591.0790.31-55-55.2-51.2-48.6-7.2-8.7-2.3-1.7-251.7-255.6-242.5-245.9平均1.247.1989.48-52.5-5.5-249.4从上表中可以看出,8+9#煤的煤层气组分以CH4为主，体积分数为84.41%~91.56%，平均为87.64%，N2为1.54%~9.41%，平均1.33%，CO2的体积分数为1.02%~11.16%，平均为8.15%。4+5#煤的煤层气以CH4为主，体积分数为84.95%~91.07%，平均为89.48%，N2为1.25%~11.79%,平均为7.19%，CO2的体积分数为2.99%~1.68%，平均为1.25%。总体上看，研究区内4+5#煤和8+9#煤气体组分差异不大，从保德地区的地层综合柱状图可以看到，煤层顶底板的岩性均以泥岩为主，局部地层为砂质泥岩，沉积相对稳定，封盖条件好，有利于煤层气的富集、成藏和保存。8+9#煤中的B1-68-4的N2含量和4+5#煤中B1-68-2的N2含量偏高，可能是因为构造原因导致空气混入煤层。图3-1N2与CH4体积分数关系进一步分析N2与CH4体积分数关系，可以看出，煤层中的N2体积分数与CH4体积分数有较好的负相关性(图4-2)，说明在该煤层中，煤层气在后期的成藏过程中较大程度受到空气影响ADDINEN.CITE<EndNote><Cite><Author>QingguangLi1</Author><Year>2015</Year><RecNum>564</RecNum><DisplayText><styleface="superscript">[32]</style></DisplayText><record><rec-number>564</rec-number><foreign-keys><keyapp="EN"db-id="90ax0pf5fw2fxlewxs9p0dsd09sravx9vfff"timestamp="1617897632">564</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>QingguangLi1,2</author><author>YiwenJu1,2CA</author><author>YuanBao1,2</author><author>ZhifengYan1,2</author><author>XiaoshiLi1,2</author><author>YingSun1,2</author></authors></contributors><titles><title>Composition,Origin,andDistributionofCoalbedMethaneintheHuaibeiCoalfield,China</title><secondary-title>Energy&Fuels</secondary-title></titles><periodical><full-title>Energy&Fuels</full-title></periodical><pages>546-555</pages><volume>Vol.29</volume><number>No.2</number><keywords><keyword>POWDERRIVER-BASIN</keyword><keyword>BIOGENICGAS</keyword><keyword>NATURAL-GAS</keyword><keyword>MOLECULARCOMPOSITION</keyword><keyword>BEDGAS</keyword><keyword>CARBON</keyword><keyword>MEXICO</keyword><keyword>GEOCHEMISTRY</keyword><keyword>ACCUMULATION</keyword><keyword>HYDROCARBONS</keyword></keywords><dates><year>2015</year></dates><isbn>0887-0624;1520-5029</isbn><urls></urls><electronic-resource-num>10.1021/ef502132u</electronic-resource-num></record></Cite></EndNote>[32]。保德地区煤层形成后，先后经历了印支、燕山和喜马拉雅等构造活动的改造，出现了强烈的抬升和剥蚀，由于煤层的抬升和剥蚀卸压，煤层中的气体发生了解吸–扩散–运移作用，煤层因抬升而暴露在了地表或与地表水相互沟通，使得大气中的氮气随水流进入煤层，从而导致煤层气氮气含量偏高，达到8.0%以上ADDINEN.CITE<EndNote><Cite><Author>李洋冰</Author><RecNum>516</RecNum><DisplayText><styleface="superscript">[33]</style></DisplayText><record><rec-number>516</rec-number><foreign-keys><keyapp="EN"db-id="90ax0pf5fw2fxlewxs9p0dsd09sravx9vfff"timestamp="1617895921">516</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>李洋冰</author><author>曾磊</author><author>胡维强</author><author>陈鑫</author><author>马立涛</author><author>刘成</author><author>黄英</author><author>乔方</author></authors></contributors><auth-address>中海油能源发展股份有限公司工程技术分公司;重庆市生态环境科学研究院;重庆市污染场地与地下水环境可持续修复工程技术研究中心;</auth-address><titles><title>保德地区煤层气地球化学特征及成因探讨</title><secondary-title>煤田地质与勘探</secondary-title></titles><periodical><full-title>煤田地质与勘探</full-title></periodical><pages>1-11</pages><keywords><keyword>保德地区</keyword><keyword>煤层气</keyword><keyword>地球化学</keyword><keyword>热成因</keyword><keyword>生物成因</keyword><keyword>同位素</keyword></keywords><dates></dates><isbn>1001-1986</isbn><call-num>61-1155/P</call-num><urls></urls><remote-database-provider>Cnki</remote-database-provider></record></Cite></EndNote>[33]。研究区8+9#煤解吸气中CO2体积分数为1.02%~11.16%，平均为8.15%；4+5#煤解吸气中CO2为1.426%~7.974%，平均5.163%。由于当CO2体积分数小于15%时就被普遍认为是有机成因气，因此研究区煤层气中的CO2可能受到其它无机成因、碳酸盐矿物溶解等因素的影响较小，大部分CO2的来源为煤有机大分子的脱羧基反应、细菌分解有机质等。8+9#煤甲烷δ13C值为-61.8‰~-50.7‰，平均-54.1‰；4+5#煤δ13C为-55‰~-48.6‰，平均-52.5‰，两层煤的煤层气均介于全国煤层气δ13C观测值(-71.7‰~-24.9‰)之间，属于轻碳同位素。8+9#煤δDCH4为-259.4‰~-248.6‰，平均-252.5‰；4+5#煤δDCH4为-255.6‰~-242.5‰，平均-249.4‰(见表3-1)。1.2煤层气成因目前，对于煤层气成因的认识通常分为两类，Rightmire、Rice将煤层气划分为生物成因气和热成因气ADDINEN.CITE<EndNote><Cite><Author>Rightmire</Author><Year>1984</Year><RecNum>578</RecNum><DisplayText><styleface="superscript">[34,35]</style></DisplayText><record><rec-number>578</rec-number><foreign-keys><keyapp="EN"db-id="90ax0pf5fw2fxlewxs9p0dsd09sravx9vfff"timestamp="1617897995">578</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Rightmire,C.T.</author><author>Eddy,G.E.</author></authors></contributors><titles><title>CoalbedMethaneResourcesoftheUnitedStates</title><secondary-title>AmericanAssociationofPetroleumGeologists</secondary-title></titles><periodical><full-title>AmericanAssociationofPetroleumGeologists</full-title></periodical><dates><year>1984</year></dates><urls></urls></record></Cite><Cite><Author>Rice</Author><Year>1993</Year><RecNum>579</RecNum><record><rec-number>579</rec-number><foreign-keys><keyapp="EN"db-id="90ax0pf5fw2fxlewxs9p0dsd09sravx9vfff"timestamp="1617897995">579</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Rice,D.D.</author></authors></contributors><titles><title>Compositionandoriginsofcoalbedgas</title><secondary-title>HydorocarbonfromCoalAapgStudiesinGeology</secondary-title></titles><periodical><full-title>HydorocarbonfromCoalAapgStudiesinGeology</full-title></periodical><volume>38</volume><dates><year>1993</year></dates><urls></urls></record></Cite></EndNote>[34,35]，Scott将煤层气划分为原生生物气、次生生物气和热成因气ADDINEN.CITE<EndNote><Cite><Author>Scott</Author><Year>1994</Year><RecNum>565</RecNum><DisplayText><styleface="superscript">[36]</style></DisplayText><record><rec-number>565</rec-number><foreign-keys><keyapp="EN"db-id="90ax0pf5fw2fxlewxs9p0dsd09sravx9vfff"timestamp="1617897632">565</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>AndrewR.Scott</author><author>W.R.Kaiser</author><author>WalterB.Ayers,Jr.</author></authors></contributors><titles><title>Thermogenicandsecondarybiogenicgases,SanJuanBasin,ColoradoandNewMexico;implicationsforcoalbedgasproducibility</title><secondary-title>AmericanAssociationofPetroleumGeologistsBulletin</secondary-title></titles><periodical><full-title>AmericanAssociationofPetroleumGeologistsBulletin</full-title></periodical><pages>1186-1209</pages><volume>Vol.78</volume><number>NO.8</number><keywords><keyword>Coalminesandmining--Degasificationofcoalbeds</keyword></keywords><dates><year>1994</year></dates><isbn>0149-1423;1558-9153</isbn><urls></urls><electronic-resource-num>10.1306/a25feaa9-171b-11d7-8645000102c1865d</electronic-resource-num></record></Cite></EndNote>[36]，Smith、宋岩等则探讨了在不同沉积环境下的煤层气甲烷碳同位素特征ADDINEN.CITEADDINEN.CITE.DATA[37,38]。1.2.1甲烷碳同位素成因使用Whiticar提出的煤层气成因图版来判断保德地区甲烷成因。图4-4（a）中显示研究区8+9#煤的煤层气主要为混合成因气或热成因气，部分样品δ13C值相对较轻，显示为次生生物成因气；4+5#煤的煤层气主要为生物成因气或热成因气。图(b)中，几乎所有的样品都处于生物成因+热成因的区域，说明所采样品均以混合成因气为主。图3-2煤层气成因类型判别版图ADDINEN.CITE<EndNote><Cite><Author>Whiticar</Author><Year>1999</Year><RecNum>635</RecNum><DisplayText><styleface="superscript">[39]</style></DisplayText><record><rec-number>635</rec-number><foreign-keys><keyapp="EN"db-id="90ax0pf5fw2fxlewxs9p0dsd09sravx9vfff"timestamp="1619422214">635</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>MichaelJ.Whiticar</author></authors></contributors><titles><title>Carbonandhydrogenisotopesystematicsofbacterialformationandoxidationofmethane</title><secondary-title>ChemicalGeology</secondary-title></titles><periodical><full-title>ChemicalGeology</full-title></periodical><pages>291-314</pages><volume>Vol.161</volume><number>No.1</number><keywords><keyword>Methane</keyword><keyword>Carbondioxide</keyword><keyword>Carbonisotopes</keyword><keyword>Hydrogenisotopes</keyword><keyword>Methanogenesis</keyword><keyword>Methanotrophy</keyword><keyword>Bacteria</keyword><keyword>Soils</keyword><keyword>Sediments</keyword></keywords><dates><year>1999</year></dates><isbn>0009-2541</isbn><urls></urls><electronic-resource-num>10.1016/s0009-2541(99)00092-3</electronic-resource-num></record></Cite></EndNote>[39]1.2.2二氧化碳同位素成因二氧化碳主要生成于有机质的低成熟演化阶段，通过含氧基团脱羧基、羰基而形成。前人研究结果表明，有机成因的二氧化碳δ13一般可以确定为-39‰~-8‰，腐殖有机质产生的二氧化碳δ13一般可以确定为-25‰~-5‰ADDINEN.CITE<EndNote><Cite><Author>戴金星</Author><Year>1993</Year><RecNum>546</RecNum><DisplayText><styleface="superscript">[40]</style></DisplayText><record><rec-number>546</rec-number><foreign-keys><keyapp="EN"db-id="90ax0pf5fw2fxlewxs9p0dsd09sravx9vfff"timestamp="1617895921">546</key></foreign-keys