ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    鄂尔多斯盆地东南缘煤层甲烷吸附特征及其主控因素研究

    Adsorption Characteristics and Main Controlling Factors of Coalbed Methane in the Southeastern Ordos Basin

    • 摘要: 煤层甲烷吸附特性作为控制煤层气富集成藏与资源评价的关键地质参数,对储层可采性预测及开发方案优化具有重要指导意义。本研究针对鄂尔多斯盆地东南缘保德-吉县-黄陵-韩城矿区,系统采集并筛选20组典型煤岩样品,开展煤岩组分定量分析、工业指标测试及甲烷等温吸附实验,运用单因素与多因素分析方法探讨影响甲烷吸附特性的主控因素。研究表明:研究区煤岩显微组分构成具显著分异特征,镜质组(2.31~77%)与惰质组(4.67~64.35%)占主导地位,壳质组(<5.7%)及矿物组分(1.17~45.09%)次之;朗格缪尔体积(VL=10.14~24.85 m3/t)与镜质组含量、镜质体最大反射率(0.67~2.60%)及碳元素含量(72.7~91.34%)呈显著正相关,而与灰分、挥发分、惰质组、壳质组、矿物组分、氢元素及氧元素含量呈负相关趋势。基于多元线性回归的敏感性分析揭示,固定碳含量(30.42~80.76%)与氢元素含量(3.04~5.37%)构成甲烷吸附能力的首要控制因素,并建立了甲烷吸附能力预测及选区评价模型为VL=0.284FCd+0.578,PL =0.631Hdaf−0.896,相关性显著。研究成果为煤层气靶区优选提供了科学依据。

       

      Abstract: The adsorption characteristics of coalbed methane serve as a critical geological parameter that governs the enrichment, accumulation, and resource evaluation of coalbed gas. These characteristics hold substantial guiding significance for predicting reservoir producibility and optimizing development strategies. In this study, 20 representative coal rock samples were systematically collected and screened from the Baode–Jixian–Huangling–Hancheng mining area located on the southeastern margin of the Ordos Basin. Comprehensive analyses were conducted, including quantitative determination of coal petrographic components, industrial property testing, and isothermal methane adsorption experiments. Single-factor and multi-factor analytical approaches were employed to identify the dominant factors influencing methane adsorption behavior. The results indicate significant heterogeneity in the microscopic composition of coal rocks within the study area. Vitrinite (2.31−77%) and inertinite (4.67−64.35%) are the predominant maceral groups, followed by liptinite (<5.7%) and mineral matter (1.17−45.09%). The Langmuir volume (VL = 10.14−24.85 m3/t) exhibits a strong positive correlation with vitrinite content, maximum vitrinite reflectance (0.67−2.60%), and carbon content (72.7−91.34%), whereas it shows a negative correlation with ash yield, volatile matter, inertinite, liptinite, mineral components, hydrogen content, and oxygen content. Sensitivity analysis based on multiple linear regression further identifies fixed carbon content (30.42−80.76%) and hydrogen content (3.04−5.37%) as the primary controlling parameters influencing methane adsorption capacity. Empirical models for predicting methane adsorption capacity and selecting favorable exploration zones were established: VL = 0.284FCd + 0.578 and PL = 0.631Hdaf − 0.896, both demonstrating statistically significant correlations. These findings provide a robust scientific foundation for the identification and prioritization of prospective coalbed methane exploration targets.

       

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