摘要
鄂尔多斯盆地陇东地区西233区长7段是中国典型的页岩油储层之一,生产初期依靠准自然能量生产,产量递减较快、采收率低。针对该区具有较为丰富的伴生气资源,选择代表性的页岩油储层岩样,结合核磁共振技术完成了注伴生气的驱替实验和吞吐实验。结果表明,在注伴生气驱油过程中,岩样采收率低于43%,主要动用了中大孔隙中的原油,微小孔隙中的原油动用程度较低;相对完全饱和油岩样,含束缚水岩样的采收率更低;岩石孔隙非均质性、比表面积和束缚水影响注伴生气驱油的采收率。在注伴生气吞吐采油过程中,岩样采收率高于44%,原油也主要从中大孔隙中采出,且相对于注伴生气驱油实验,吞吐采油过程中各级孔隙中的原油动用程度更高;随着吞吐周期的增加,周期采收率逐渐降低,吞吐效果趋于稳定;吞吐压力越高,吞吐采油越多,采收率越高。研究证实高于地层压力的注伴生气吞吐更能提高西233区长7页岩油储层原油的采收率,建议研究区采用超前注气吞吐的开发方式。
Xi233 area Chang7 reservoir in Ordos Basin is one of the typical shale oil reservoirs in China.In the early stage of production relying on quasi-natural energy,oil production declines fast and oil recovery is low.Given abundant associat⁃ed gas resources,we selected typical shale oil reservoir rock samples to conduct the gas-flooding experiment and huff-puff experiment in the shale oil samples with the associated gas by the nuclear magnetic resonance technology.The results show that the oil is mainly produced from the medium and large pores,while the recovery percent of micropores is lower,and oil recovery is less than 43%in the associated gas-flooding process.Compared with the saturated oil samples,the samples with irreducible water show the lower oil recovery,which is affected by factors such as pore heterogeneity,specific surface area,and irreducible water.In the huff-puff process with associated gas injection,oil is also mainly produced from the me⁃dium and large pores.Compared with the flooding experiment with associated gas injection,the recovery percent in each level of pores is greater in the huff-puff oil recovery process,and the oil recovery of samples is greater than 44%.With the increase in the huff-puff cycle,the cycle oil recovery gradually decreases,and oil production tends to be steady.As the huff-puff pressure rises,both the oil production and the oil recovery increase.The study confirms that the huff-puff pres⁃sure higher than the formation pressure can improve the oil recovery in Xi233 area Chang7 shale oil reservoir.The develop⁃ment method of advanced gas injection huff-puff is recommended in the study area.
作者
肖文联
任吉田
王磊飞
陈波
李杰
杨玉斌
郑玲丽
XIAO Wenlian;REN Jitian;WANG Leifei;CHEN Bo;LI Jie;YANG Yubin;ZHENG Lingli(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu City,Sichuan Province,610500,China;Construction Project Team of Shale Oil Productivity,PetroChina Changqing Oilfield Company,Qingyang City,Gansu Province,745000,China)
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2022年第5期91-101,共11页
Petroleum Geology and Recovery Efficiency
基金
国家自然科学基金联合基金重点支持项目“黏度可控的原位增黏体系构建及高效驱油机理研究”(U19B2010)
西南石油大学非常规油气渗流物理青年科技创新团队(2018CXTD10)。
关键词
页岩油
伴生气
吞吐压力
气驱油
微观结构
非均质性
鄂尔多斯盆地
shale oil
associated gas
huff-puff pressure
gas-flooding
microstructure
heterogeneity
Ordos Basin
