华南晚二叠世“树皮体”显微傅里叶红外光谱(Micro-FTIR)特征及意义

Characteristics and Implications of Micro-FTIR Spectroscopy of “Barkinite” from Upper Permian Coals, South China

在高纯度煤岩显微组分分离富集的基础上 ,应用透射式显微傅里叶红外光谱技术 (Micro FTIR) ,对华南晚二叠世煤中中国特有的显微组分———树皮体———的化学结构进行了测定 ,并与新疆吐哈盆地侏罗纪煤中的镜质体、丝质体和孢子体进行对比。结果表明 :树皮体与孢子体的红外光谱特征较为相近 ,主要由长链脂族结构组成 ,芳香结构和含氧基团相对较少。此特点与镜质体和丝质体主要由芳香结构组成、脂肪族结构 (尤其是长链脂肪烃 )含量相对较少 (或很少 )明显不同。上述结构特征决定了树皮体与孢子体类似 ,是一种油气生成潜力较大的显微组分。此特点对在华南地区寻找与富含树皮体煤系地层有关的油气资源具有重要的意义。

Based on the high-purity coal macerals separating and concentrating, Micro-FTIR technique was used to investigate the chemical compositions and structures of barkinite from Late Permian coals in South China, and parallel studies were also carried out on vitrinite, fusinite and sporinite from the Jurassic coals in Turpan basin, Northwest China. The results show that the Micro-FTIR spectra of barkinite and sporinite are very similar, the chemical structures of them are mainly composed of long aliphatic-side chain, and minor amounts of aromatic compounds; whereas vitrinite and fusinite are mainly composed of aromatic compounds, in addition to a few aliphatic compounds. The IR characteristics indicate that barkinite and sporinite are all the best oil source macerals, with high hydrocarbon-generating potential; vitrinite is one of the gas source macerals with lower hydrocarbon-generating potential; fusinite has the lowest hydrocarbon-generating potential. The high hydrocarbon-generating potential of barkinite is important for exploring oil and gas sources from barkinite-rich coals in South China.=