黔北牛蹄塘组和龙马溪组沉积环境及有机质富集机理——以RY1井和XY1井为例

发布时间：2018-04-19 04:17

本文选题：沉积环境 + 有机质富集差异　；参考：《矿物岩石》2017年03期

【摘要】：下寒武统牛蹄塘组和下志留统龙马溪组是我国南方海相页岩气勘探的优选层位,调查结果显示RY1井牛蹄塘组总有机碳含量平均为4.24%,XY1井龙马溪组总有机碳含量平均为2.08%,且中国南方牛蹄塘组总有机碳含量普遍高于龙马溪组。为探究二者有机质富集差异,研究基于RY1井和XY1井样品,采用具有环境意义的矿物学和微量元素地球化学方法,对这两套富有机质页岩的古气候、古氧化还原条件、深部物源和上升洋流等沉积环境条件展开讨论。RY1井样品Sr/Cu除去异常点后平均值为2.69,XY1井样品Sr/Cu平均值为5.205,认为牛蹄塘组形成条件更为温湿,有利于有机质的富集;还原条件有利于有机质的保存,V/Cr值结果表明牛蹄塘组还原性更强,但其有机质的富集可能还受到其他因素影响;RY1井样品Co/Zn平均值为0.098,XY1井样品Co/Zn平均值为0.153,结合微量元素、铂族元素等分析结果,认为牛蹄塘组和龙马溪组在形成时受深部物源的作用,且牛蹄塘组受到的作用更显著;上升洋流将洋底的营养物质带到陆棚环境中,提高有机质的生产率,使有机质富集,稀土元素数据显示上升洋流对牛蹄塘组作用显著,而对龙马溪组作用不明显,因此有机质富集程度不如牛蹄塘组。
[Abstract]:The Niutetang formation of the Lower Cambrian and the Longmaxi formation of the Lower Silurian are the best selected horizons for marine shale gas exploration in southern China.The results showed that the average total organic carbon content of the Niulitang formation in the RY1 well was 4.24. The average total organic carbon content of the Longmaxi formation in the XY1 well was 2.08, and the total organic carbon content of the Niulitang formation in southern China was generally higher than that of the Longmaxi formation.In order to explore the difference of enrichment of organic matter between the two wells, the paleoclimate and paleo redox conditions of these two organic shale were studied by using the mineralogical and trace element geochemical methods of environmental significance based on the samples of RY1 well and XY1 well.The sedimentary environment conditions such as deep provenance and rising ocean current are discussed. The average value of Sr/Cu in well RY1 is 5.205 after removing abnormal points. It is considered that the formation conditions of Niulitang formation are warmer and wetter, which is beneficial to the enrichment of organic matter.The reduction conditions were favorable to the preservation of organic matter and the V / Cr values showed that the reduction of organic matter was stronger in Niulitang formation, but the enrichment of organic matter might also be affected by other factors. The average value of Co/Zn of the samples of RY1 well was 0.098 XY1, the average Co/Zn of samples was 0.153, which combined with trace elements.The results of platinum group analysis show that the Niulitang formation and Longmaxi formation were affected by the deep provenance, and the Niulitang formation was affected more obviously, and the rising ocean current brought the nutrients from the ocean floor to the shelf environment.The data of rare earth elements showed that the rising ocean current played a significant role in Niulitang formation, but not in Longmaxi formation, so the enrichment degree of organic matter was lower than that of Niulitang formation.
【作者单位】：中国地质大学(北京)地球科学与资源学院;中国石油化工华东油气分公司南川页岩气项目部;
【基金】：国家自然科学基金面上项目“中国南方海相富有机质页岩孔隙特征及其对页岩气储集与扩散迁移的制约”(41572134)
【分类号】：P618.13

【相似文献】