摘要
柴达木盆地北缘侏罗系是中国西北地区重要的含煤岩系，同时也是重要的烃源岩层段。在柴北缘侏罗系有多个厚层泥页岩分布区，整体来看西北部泥页岩厚度大于东南部，其中鄂博梁一冷湖地区在中侏罗世长期处于沉积中心，沉积环境主要为浅湖和半深湖，水体稳定，碎屑物质供给充足，沉积了一套厚一巨厚层泥页岩，有效泥页岩厚度在600～1200m。根据干酪根元素组成等测试结果，研究区侏罗系泥页岩中的有机质类型为Ⅱ-Ⅲ2型，以生气为主生油为辅。泥页岩有机碳平均含量为2．02％，其中冷湖地区泥页岩有机质含量最高，可达8．26％。中、下侏罗统烃源岩除鱼卡、大煤沟成熟度较小外，其它地区均进入生气高峰期，个别地区已达过成熟阶段。柴北缘侏罗系泥页岩厚度大、有机质含量较高，成熟度适中，初步认为具备形成页岩气藏的良好地质条件。
The Jurassic System in the northern Qaidam Basin is a major coal-hearing rock series in northwestern China, also an impor- tant source rock sector. The Jurassic System in the area has multiple thick argillutite distribution regions; overall, argillutite in north- western part is thicker than in southeastern part. In which, the Obo Liang--Lenghu area was the long-lasting depositional center dur- ing Middle Jurassic Epoch, the environment was mainly shallow and semi-deep lakes with sufficient clastic material supply, thus de- posited a set of thick to very thick argillutite with effective thickness 600-1200m. Based on the tested data of kerogen elemental compo- sitions, the type of organic matter belongs to type Ⅱ-Ⅲ2, mainly gas-generating supplemented with oil-generating. Average content of organic carbon is 2.02%, the highest in Lenghu area can be 8.26%. The maturity of middle and lower Jurassic source rocks is all in gas- generating peak period, locally has reached over mature period, except poor maturity in Iqe and Dameigou areas. In summary, Jurassic argillutite in northern Qaidam Basin has large thickness, higher organic matter content and modest maturity, thus can conclude that there possesses favorable geological conditions for shale gas formation.
出处
《中国煤炭地质》
2014年第1期26-33,共8页
Coal Geology of China
关键词
柴达木盆地北缘
侏罗系
页岩气
资源潜力
northern Qaidam Basin
Jurassic System
shale gas
resource potential
