柴达木盆地东部地区生物气形成机制

Formation mechanism of biogas in eastern Qaidam Basin

周飞 段生盛 张永庶 隋国杰 刘莹 徐子远 侯泽生 尹玉红1

中国石油青海油田公司勘探开发研究院，甘肃 敦煌 736202 中国石油青海油田公司勘探事业部，甘肃 敦煌 736202 中国石油青海油田公司诚信服务公司，甘肃 敦煌 736202 中国石油大学（北京）地球科学学院，北京 102249

Research Institute of Exploration and Development, Qinghai Oilfield Company, PetroChina, Dunhuang 736202, China Exploration Department, Qinghai Oilfield Company, PetroChina, Dunhuang 736202, China Chengxin Services Company, Qinghai Oilfield Company, PetroChina, Dunhuang 736202, China College of Geosciences, China University of Petroleum, Beijing 102249, China

生物气是沉积物在成岩作用早期受生物化学作用形成的最终产物之一。对生物产气模式的传统认识是，沉积有机质在厌氧环境下，经微生物降解为能被产甲烷菌利用的小分子底物，然后通过乙酸发酵和CO2还原，形成甲烷。文中突破传统认识，提出弱成岩阶段的低温热力与微生物共同作用是柴东地区生物气形成的主要机制。传统认识强调继承性活性有机质的作用，而文中分析发现，柴达木盆地东部第四系沉积物内继承性活性有机质并不丰富。研究认为，在低温热力作用下可产生一些次生活性有机质，该部分物质为一定埋藏深度的生物甲烷气提供重要营养底物来源。

Biogas is one of the ultimate products of sediments in the early stage of diagenesis controlled by biochemical function. The conventional biological gas production pattern believed that the sedimentary organic matters were degraded into small molecule substrates in anaerobic environment by microorganism which could be used by methanogen bacteria and then converted to methane through acetate fermentation and carbon dioxide reduction. This paper breaks through the traditional understanding and puts out that low temperature thermodynamic and microbiological action are the main mechanisms for biogas production in eastern Qaidam Basin. The traditional model overstresses the role of inherited active organic matter. The analysis shows that the Quaternary inherited active organic matters in sediments are not abundant. Study indicates that it can produce some secondary active organic matters which can supply important nutrition substrates source for the biomethane buried at certain depth.

10.6056/dkyqt201304004