页岩的气体解析特征及地球化学认识——以鄂尔多斯盆地中南部长7段页岩为例

发布时间：2018-01-16 11:29

本文关键词：页岩的气体解析特征及地球化学认识——以鄂尔多斯盆地中南部长7段页岩为例　出处：《中国矿业大学学报》2017年03期 　论文类型：期刊论文

【摘要】：鄂尔多斯盆地中南部地区发育含气的长7段页岩.为了充分认识长7段页岩气的生成过程、运移过程以及成藏演化过程,以气体化学与同位素化学相结合为手段,研究了不同气体组分及其同位素在解析过程中的含量变化,认为在页岩气的解析过程中,甲烷的含量逐渐降低,重烃气的含量逐渐升高,气体的干燥系数降低;甲烷的碳同位素逐渐增重,重烃气的碳同位素变化不明显.研究结果表明:解析过程中,二氧化碳体积分数变化范围为0.53%~5.15%,氮气体积分数变化范围为1.24%~4.64%,气体干燥系数在0.43~0.82之间,甲烷碳同位素变化范围为-51.6‰~-33.9‰.基于长7段页岩的气体解析特征,得出长7段页岩气为腐泥型母质生成的油型热解气;长7段页岩对二氧化碳的吸附能力最强,对甲烷的吸附能力次之,对氮气的吸附能力最弱;烷烃气体中,气体的分子体积越小,其在页岩内部的初次运移能力越强;页岩中,吸附态、溶解态及游离态3种赋存相态的页岩气在地质历史过程中不断转化与调整;长7段页岩的平均含气量大致为1.90m3/t.
[Abstract]:South central area of Ordos basin gas Chang 7 shale. In order to fully understand the formation process of Chang 7 shale gas migration and accumulation, the process of evolution, as gases and Isotopic Chemistry combination as a means of different gas composition and isotope analysis in the process of the change of the content, as in the analytical process of shale gas, methane content decreased gradually, the content of heavy hydrocarbon gas gradually increased, reducing the drying coefficient of gas; carbon isotope of methane increased gradually, carbon isotope variation of heavy hydrocarbon gas is not obvious. The results show that the analytical process, the variation range of carbon dioxide 0.53%~5.15% volume fraction, the variation range of nitrogen gas volume 1.24%~4.64% score, gas drying coefficient between 0.43~0.82, the variation range of methane carbon isotope is -51.6% ~-33.9%. Characteristics of Chang 7 shale gas analysis based on the 7 section Shale gas is rotten mud generated oil pyrolysis; Chang 7 shale on the CO2 adsorption capacity of methane adsorption capacity of the strongest, the second, the nitrogen adsorption capacity of the weakest; alkane gas, gas molecular volume is small, the shale internal primary migration ability; adsorption shale, dissolved, and free the 3 existing phase of shale gas in the geological history in the process of continuous transformation and adjustment; average gas content of Chang 7 shale is roughly 1.90m3/t.

【作者单位】：延安大学石油工程与环境工程学院;陕西延长石油(集团)有限责任公司;
【基金】：陕西省科技统筹创新工程计划项目(2012KTZB03-03-01-01) 延安大学博士科研启动项目(YDBK2016-15)
【分类号】：TE122.3
【正文快照】： 随着针对页岩气地质研究的深入,页岩对气体的吸附能力逐渐被业界认识.在吸附气含量较高的部分页岩气产区,气体的充分解析保证了页岩气井的稳产[1-2].由此,针对页岩的解析实验及吸附实验逐渐开展起来,文献[3]对气体的化学组成与同位素组成进行了研究.在气体化学组成及同位素组

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