烃源岩特征与生烃动力学研究——以准噶尔盆地吉木萨尔凹陷芦草沟组为例

准噶尔盆地吉木萨尔凹陷二叠系芦草沟组含有丰富的油气资源，其烃源岩主要有页岩、碳酸盐质页岩和粉砂质泥岩，它们均具有有机质丰度高、生烃潜力大、当前处于低成熟至成熟阶段、有机质类型以Ⅰ型和Ⅱ型为主的特征，在对其特征进行评价的基础上，选取中-低成熟度、有机质丰度较高的烃源岩进行开放体系条件下的热解实验和动力学模拟实验，进而研究烃源岩样品的生排烃特征。结果表明，芦草沟组烃源岩活化能主要为210 kJ/mol；上述3 种烃源岩中，页岩具有最高的生烃量和排烃效率，碳酸盐质页岩次之，而粉砂质泥岩的生烃量和排烃率均最低，但前两者却具有较高的滞留烃含量。综合前人的研究成果，最终认为芦草沟组烃源岩生烃增压作用是烃源岩排烃和致密油气聚集的主要动力，页岩和碳酸盐质页岩段是致密油勘探的目标层段。

Source rock characteristics and hydrocarbon generation kinetics: A case study of the Permian Lucaogou Formation in Jimusar Sag,Junggar Basin

There are abundant petroleum resources in the Permian Lucaogou Formation in Jimusar Sag, Junggar Basin. The source rock types of the Lucaogou Formation include shale, carbonate shale and silty mudstone. These source rocks are characterized by high organic carbon content, high hydrocarbon generation potential, low maturity to maturity and Ⅰ-Ⅱ type kerogen. Based on conventional organic geochemistry evaluation of the source rocks, the source rock samples with low?middle maturity and high organic carbon content were selected to carry out pyrolysis and hydrocarbon generation kinetics simulation experiments under open system, and the haracteristics of the hydrocarbon generation and expulsion were studied. The results show that the reaction activation energy of the sourcerocks is 210 kJ/mol. The hydrocarbon generation and expulsion characteristics of the three kinds of source rocks are different. The shale has the highest hydrocarbon generation content and hydrocarbon expulsion rate, followed by carbonate shale, and the silty mudstone has the lowest hydrocarbon generation content and hydrocarbon expulsion rate. It is considered that the main driving force of the hydrocarbon expulsion and tight oil accumulation is the pressure increased by the hydrocarbon generation of source rocks in the Lucaogou Formation, and the shale and carbonate shale are the favorable targets for tight oil exploration.