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通过对塔里木盆地柯坪地区苏盖特布拉克剖面肖尔布拉克组下段40个样品的微量、稀土元素进行测试分析,结合有机碳TOC含量变化,研究表明该地区Ce/Ce*与Eu/Eu*、(Dy/Sm)_(SN)、∑REE均无相关性,反映成岩作用对元素含量影响较小,数据能反映沉积时期真实环境情况。利用Ti元素排除Ba、Cu、Zn元素中陆源影响,得到生源元素校正值Ba_(xs)、Cu_(xs)、Zn_(xs)及其综合系数Y判断肖尔布拉克组下段纵向上下部古生产力水平高于上部。TOC最大值可达5.14%,平均值为1.96%,总体表现为与古生产力水平相似特征。U/Th、V/(V+Ni)、δU、Ce_(anom)比值判断肖尔布拉克组下段沉积时期处在贫氧—缺氧的环境,后期遭到破坏,印证了早寒武世海侵后海平面下降发生海退的过程。利用Mn/Ti值表征海平面变化,经历了浅且稳定→深且具有波动性→最浅且稳定的变化过程,结合上述判别指标与TOC测量值,说明研究区肖尔布拉克组下段中下部为优质潜在烃源岩。
Based on the analysis of the trace and rare earth elements in the 40 samples of the Lower Shoblak Formation in the Lower Khotabrake Formation in the Keping area of the Tarim Basin and the changes of the TOC content in the organic carbon, it is shown that Ce / Ce * and Eu / Eu *, (Dy / Sm) _ (SN) and ΣREE, which reflect that the diagenesis has little effect on the elemental content, and the data can reflect the real environment during the depositional period. By using Ti element to exclude the influence of terrigenous elements in Ba, Cu and Zn elements, the correction values Ba xs, Cu xs, Zn xs and their synthetic factors Y were obtained to determine the paleo-productivity in the lower part of the Shorburak Formation The level is higher than the upper part. The maximum value of TOC is up to 5.14% with an average of 1.96%. The overall TOC is similar to the level of the productivity of the ancient. U / Th, V / (V + Ni), δU, and anom ratios to determine the lower oxygen and anoxic environment during the lower part of the Shoballak formation, Flat decline in the process of regression. The change of sea level is characterized by Mn / Ti value, and experienced shallow and stable → deep and fluctuant → the shallowst and stable change course. Combining the above discriminant index and TOC measurement, it shows that the middle and lower part of the lower part of the Shoballak Formation in the study area High-quality potential source rock.