中国典型盆地陆相页岩油组分评价及意义

Evaluation of the compositions of lacustrine shale oil in China’s typical basins and its implications

李明 王民 张金友 张宇辰 刘召 雒斌 卞从胜 李进步 王鑫 赵信斌 董尚德

Ming LI Min WANG Jinyou ZHANG Yuchen ZHANG Zhao LIU Bin LUO Congsheng BIAN Jinbu LI Xin WANG Xinbin ZHAO Shangde DONG

页岩油组分是揭示页岩油富集机制的基础，也是研究页岩孔隙内油-水-岩相互作用必不可少的参数。选择松辽盆地古龙凹陷白垩系青山口组一段纯页岩型页岩油、渤海湾盆地济阳坳陷东营凹陷古近系沙河街组四段纯上次亚段过渡型页岩油和鄂尔多斯盆地三叠系延长组7段3亚段纯页岩型页岩油作为研究对象，利用保压取心、常规取心、页岩层段产出油及高压釜热模拟产物，开展全烃色谱、热解气相色谱等实验，进行不同成熟度和不同类型页岩油组分系统评价。总结获取页岩油组分的方法，对比不同方法评价结果，讨论页岩残留烃组分的控制因素，提出页岩油组分评价方案。明确了产出油组分、热释烃组分、抽提物组分和热模拟产物组分间的差异以及上述评价方法的局限，解释了高有机碳丰度层段高含油率原因，高有机碳丰度层段代表高含油率，但不一定代表页岩油可动比例高。页岩热演化程度直接控制页岩油组分，有机质丰度和孔隙结构对页岩残留烃组分有一定影响。在页岩含油率评价、流体赋存特征以及页岩油富集机制研究时需考虑烃类散失，尤其是中-高成熟页岩。不同成熟度页岩油的组分评价为揭示页岩纳米孔内流体赋存特征提供新的方法。

Shale oil composition serves as both a basis for revealing the shale oil enrichment mechanism and an essential parameter used to explore the interactions among oil， water， and rocks in the pores. We investigate the shale oil reservoir of pure shale type in the 1 member in the Qingshankou Formation in the Gulong Sag， Songliao Basin； the shale oil reservoir of transitional type in the Chunshang interval of the upper sub-member of the 4 member of the Shahejie Formation in the Dongying Sag， Jiyang Depression， Bohai Bay Basin； and the shale oil reservoir of pure shale type in the 3 sub-member of the 7 member of the Yanchang Formation， Ordos Basin. Shale samples taken bypressure-retained coring and conventional coring， as well as oil produced from the three shale intervals and the products of autoclave-based thermal simulation experiment， are subjected to composition analysis. The composition of shale oil of diverse types and with varying maturity is characterized through chromatography to determine the total petroleum hydrocarbons （TPH） and pyrolysis-gas chromatography （PY-GC）. The methods for deriving shale oil compositions are comprehensively summarized and compared in terms of result， and the factors affecting the composition after evaporative loss are discussed. The assessment scheme is proposed at last. Consequently， we identify the compositional differences for the produced oil， thermally desorbed hydrocarbons， shale extracts， and products from thermal simulation experiment， as well as clarify the limitations of the above-mentioned evaluation methods. Additionally， the phenomenon that shale intervals with high total organic carbon （） content tend to be of high oil content is illustrated， as revealed in previous studies. However， these intervals of high oil content do not necessarily reflect a high ratio of mobile to total oil volume. Shale maturity directly determines the composition of shale oil， while the abundance of organic matter and pore structures exert certain effects on the composition of residual hydrocarbons in shales. As indicated by the results of this study， it is necessary to consider hydrocarbon evaporativeloss in evaluating oil content in shales and exploring fluid occurrence state and shale oil enrichment mechanism， especially for shales of medium to high maturity. The composition evaluation of shale oil at varying maturity can provide new insights for revealing the fluid occurrence characteristics in shale nanopores.

10.11743/ogg20230612