松辽盆地南部青山口组页岩油储集空间及富集模式研究

Research on the Storage Space and Enrichment Model of Shale Oil in Qingshankou Formation in Southern Songliao Basin

为了解页岩油资源储量和富集模式,采用一体化评价体系方法,分析了松辽盆地青山口组一段页岩油储层特征并进行评价。为了表征含有Ⅰ型有机质的湖相页岩的孔隙演化特征,对湖相页岩样品进行含水热解实验,使其达到各种成熟度。使用二氯甲烷萃取具有不同成熟度的样品,对萃取前后的样品进行总有机碳含量、Rock-Eval热解和低压气体(CO_(2)和N_(2))吸附分析。结果表明,提取样品的微孔(<2 nm)体积和表面积远高于人工样品,但提取样品的中孔(2~50 nm)参数与之前的样品接近,这说明液态烃主要储存在微孔中。提取样品的孔隙体积和矿物含量之间没有任何明显的相关性,表明成熟度是孔隙结构的主要控制因素。研究结果有助于对湖相页岩孔隙演化的理解,为页岩油储存提供启示。

In order to know the shale oil storage and enrichment model,the study adopts integration evaluation system method,and analyzes the characteristics and evaluation of shale oil reservoirs in a section of Qingshankou Formation in Songliao Basin.In order to characterize the pore evolution characteristics of lacustrine shale containing type Ⅰ organic matter,we performed hydrous pyrolysis experiments on lacustrine shale samples to reach various maturity levels.Samples with different maturity levels were then extracted through using dichloromethane.The samples before and after extraction were analyzed for total organic carbon content,Rock-Eval pyrolysis and low pressure gas(CO_(2)and N_(2))adsorption.The results show that the micropore(<2 nm)volume and surface area of the extracted samples are much higher than those of the artificial samples,but the mesopore(2~50 nm)parameters of the extracted samples are close to the previous samples,indicating that liquid hydrocarbons are mainly stored in the micropores.There is no apparent correlation between the pore volume and mineral content of the extracted samples,suggesting that maturity is the main controlling factor for pore structure.Our findings can improve the understanding of lacustrine shale pore evolution and provide some implications for shale oil storage.