本文選題：菱鐵礦　切入點：隔水阻氣層　出處：《地學(xué)前緣》2017年06期 　論文類型：期刊論文

【摘要】：基于黔西地區(qū)晚二疊世含煤地層鉆井巖心觀察及樣品分析測試結(jié)果,研究了煤系中含菱鐵礦與黃鐵礦層的巖石學(xué)特征,劃分了6種含菱鐵礦與黃鐵礦層的垂向沉積序列,歸納總結(jié)了5種菱鐵礦與黃鐵礦的發(fā)育模式,指出含菱鐵礦層的發(fā)育對"多層疊置獨立含煤層氣系統(tǒng)"的發(fā)育具顯著的控制作用。研究結(jié)果表明,研究區(qū)內(nèi)菱鐵礦中CO_2的來源與沉積有機質(zhì)和海相碳酸鹽巖有關(guān),其中,形成于海平面上升背景下的菱鐵礦中CO_2的同位素特征與海相碳酸鹽巖同位素特征相似,形成于海平面下降背景下菱鐵礦中的CO_2主要來源于沉積有機質(zhì),海平面持續(xù)較高背景下的發(fā)育的菱鐵礦則受沉積有機質(zhì)與海水的共同影響,此外成巖環(huán)境的改變導(dǎo)致形成菱鐵礦與黃鐵礦的共生組合。含煤巖系中含菱鐵質(zhì)(黃鐵礦)的泥巖及粉-細砂巖具低孔、低滲特征,可作為含氣單元間的隔水阻氣層,這種巖層的分布受控于沉積環(huán)境及區(qū)域海平面變化,對"多層疊置獨立含煤層氣系統(tǒng)"的形成具有分劃性的阻隔作用。
[Abstract]:Based on the core observation and sample analysis of late Permian coal-bearing strata in western Guizhou, the petrological characteristics of siderite and pyrite layers in coal measures are studied, and six vertical sedimentary sequences of siderite and pyrite layers are divided. Five development models of siderite and pyrite are summarized, and it is pointed out that the development of siderite bearing strata has a significant effect on the development of "multi-layer superposition independent coal-bearing methane system". The origin of CO_2 in siderite is related to sedimentary organic matter and marine carbonate rocks. The isotopic characteristics of CO_2 in siderite formed in the sea level rise background are similar to those of marine carbonate rocks. The CO_2 in siderite formed in the background of sea level drop is mainly derived from sedimentary organic matter, while siderite, which develops in a higher sea level, is affected by both sedimentary organic matter and sea water. In addition, the change of diagenetic environment resulted in a symbiotic association of siderite and pyrite. The mudstone and silt-fine sandstone containing rhombotite (pyrite) in the coal-bearing rock series have low porosity and low permeability, which can be used as water barrier and gas barrier between gas-bearing units. The distribution of the strata is controlled by the sedimentary environment and the regional sea level change, which has a partition effect on the formation of "multi-layer independent coal-bed methane system".
【作者單位】： 中國礦業(yè)大學(xué)煤層氣資源與成藏過程教育部重點實驗室;中國礦業(yè)大學(xué)資源與地球科學(xué)學(xué)院;貴州省煤層氣頁巖氣工程技術(shù)研究中心;貴州省煤田地質(zhì)局;
【基金】：國家自然科學(xué)基金項目(41102100,41541046,41672146) 國家科技重大專項項目(2016ZX05044-002-001)
【分類號】：P618.31
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本文編號：1638488