摘要
CO_(2)在页岩油藏驱油时的孔隙动用特征是评价其应用于提高页岩油藏采收率效果的一项重要指标。因此,开展了超临界CO_(2)驱替页岩岩心室内实验,并以核磁共振(NMR)在线岩心扫描技术为手段对CO_(2)驱页岩油藏的孔隙动用特征和规律进行研究。结果表明,超临界CO_(2)非混相驱油主要动用页岩中孔隙半径在0.1~3.0µm范围内的油,而此过程中小于0.008µm孔隙半径内的油量反而增加,分析原因主要是CO_(2)在页岩层中通过压差和扩散作用将大孔隙内页岩油带入小孔隙中并发生吸附滞留,在驱替时间5 h后,CO_(2)驱替页岩油采收率达到35.7%,驱油效果较好。
The pore utilization characteristics of CO_(2) during shale oil displacement are a crucial indicator for evaluating its effectiveness in enhancing shale oil reservoir recovery rates.Therefore,experiments on supercritical CO_(2) displacing shale cores were conducted in the laboratory,and nuclear magnetic resonance(NMR)online core scanning technology was used to study the pore utilization characteristics and patterns of CO_(2) displacement in shale oil reservoirs.The results indicate that immiscible flooding by supercritical CO_(2) mainly develops the oil in shale pores with radius of 0.1~3.0µm,but the oil content in pore radius less than 0.008µm actually increases.The analysis shows that CO_(2) brings shale oil from large pores into small pores through pressure difference and diffusion effect in the shale layer and makes oil undergo adsorption and retention.After a displacement time of five hours,the recovery rate of shale oil by CO_(2) displacement reached 35.7%,indicating a relatively effective oil displacement result.
作者
张志超
柏明星
杜思宇
ZHANG Zhichao;BAI Mingxing;DU Siyu(Key Laboratory of EOR,Ministry of Education,Northeast Petroleum University,Daqing,Heilongjiang 163318,China)
出处
《油气藏评价与开发》
CSCD
北大核心
2024年第1期42-47,共6页
Petroleum Reservoir Evaluation and Development
基金
国家自然科学基金“枯竭油藏型储气库二氧化碳作垫层气机理及注采动态规律研究”(52174020)。
关键词
超临界CO_(2)
页岩油
核磁共振
孔隙动用特征
采收率
supercritical CO_(2)
shale oil
nuclear magnetic resonance
pore development characteristic
oil recovery