泥页岩热模拟排出油与滞留油中17(H)-重排藿烷的成熟度指示规律

Maturity indication of 17(H)-diahopane in expelled and retained oils from artificial maturation experiments of mud shale

李姗姗 白斌 严刚 徐耀辉 刘岩

LI Shanshan BAI Bin YAN Gang XU Yaohui LIU Yan

油气地球化学与环境湖北省重点实验室(长江大学 资源与环境学院), 武汉 430100 油气资源与勘探技术教育部重点实验室(长江大学), 武汉 430100 中国石油勘探开发研究院, 北京 100083

Hubei Key Laboratory of Petroleum Geochemistry and Environment(School of Resources and Environment, Yangtze University), Wuhan, Hubei 430100, China Key Laboratory of Exploration Technologies for Oil and Gas Resources of Ministry of Education (Yangtze University), Wuhan, Hubei 430100, China Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China

在沉积有机相接近的前提条件下，重排藿烷的相对丰度与热成熟度密切相关。选用鄂尔多斯盆地低熟(Ro为0.58%)富有机质(总有机碳含量为3.87%)泥页岩进行生排烃热模拟实验，通过气相色谱—质谱(GC-MS)对排出油和滞留油中17α(H)-重排藿类化合物进行了检测与分析，并结合热模拟残余岩样的实测镜质体随机反射率(Ro)界定了17α(H)-重排藿烷参数作为成熟度指标的适用范围。结果表明，无论在排出油还是滞留油中，参数C29*/(C29*+C29H)和C30*/(C30*+C30H)呈现出类似的三段式变化特征，均随实验温度的升高先降低后升高最后降低，表明两个参数可能是较好的油源对比指标。在325 ℃之前，即Ro＜1.01%时，参数变化幅度均不明显；但在325~385 ℃之间，两个参数均随温度的升高呈现显著的上升趋势，表明在有机质成熟中期—高成熟早期阶段(1.01%＜Ro＜1.48%)两个参数均可作为有效的成熟度指标。

With the comparable sedimentary organic phase, the relative abundance of rearranged hopanes can be correlated to maturity degree. By the approach of artificial maturation experiments of low-maturity (Ro=0.58%) and organic-rich (TOC=3.87%) mud shale collected from the Ordos Basin, 17α(H)-diahopanes in expelled and retained oils were examined by gas chromatography-mass spectrometry (GC-MS). The thermal evolution characteristics of parameters related to 17α(H)-diahopane were discussed, and the maturity range of these parameters as maturity indicators was proposed, combined with the random mean vitrinite reflectance (Ro) of maturated rock samples of each step of pyrolysis. Results show that the parameters of C29*/(C29*+C29H) and C30*/(C30*+C30H) have similar three-stage variations. As experimental temperature increased, the values of the two parameters decreased firstly, then increased and finally decreased again, indicating that they may be good indicators for oil-source correlation. Before 325 ℃, i.e. Ro < 1.01%, both parameters showed insignificant changes. However, they both showed an obvious upward trend with increasing temperature from 325 to 385 ℃, indicating that they were valid indicators for maturity from the moderate to the early stages of high maturity (i.e. 1.01% < Ro < 1.48%).

国家自然科学基金项目 41972122;国家自然科学基金项目 42072186

https://doi.org/10.11781/sysydz202205887