摘要
三塘湖油田NJH区块属于中黏油砂岩油藏,地层原油黏度为20.8 mPa·s,处于中含水期,预测水驱采收率为22.70%,提高采收率空间小。为了探索提高采收率技术,检验中黏油CO_(2)近混相驱可行性,揭示CO_(2)近混相驱相间传质规律及增油机理,开展了CO_(2)驱油室内实验及矿场试验。结果表明:CO_(2)驱前缘主要发挥溶胀作用,后缘萃取抽提作用强于前缘,降黏作用及提高剩余油驱油效率是主要的增油机理,地面原油黏度降幅为55%,C_(2)—C_(15)含量升高18.3%,驱油效率提高4.6倍;渗透率级差是影响波及体积的主要因素,渗透率级差达到6,低渗透层采收率仅为13.84%。矿场试验阶段累计注气量为2.66×10^(4) t,累计产油量为0.78×10^(4) t,换油率达到0.29,证实中黏油CO_(2)近混相驱具备良好的推广应用前景。
The NJH block of the Santanghu oilfield features sandstone reservoirs containing medium-viscosity oil,with crude oil viscosity of 20.8 mPa·s.The reservoir is at medium water cut stage,with a predicted waterflood recovery factor of 22.70%,leaving a limited potential for further enhanced oil recovery.To figure out an applicable enhanced oil recovery(EOR)technique,laboratory experiments and field test were conducted on CO_(2) near-miscible flooding for medium-viscosity oil to understand the mass transfer patterns and EOR mechanisms of this technique,thereby determining its feasibility.The research results show that the front of the CO_(2) flooding mainly plays a swelling effect,and the rear exerts a stronger extraction effect than the front.Reducing the viscosity and improving the remaining oil displacement efficiency are the main stimulation mechanisms.The viscosity of surface crude oil reduced by 55%,the content of C_(2)-C_(15) components increased by 18.3%,and the displacement efficiency improved by 4.6 times.Permeability ratio is found to be the primary factor influencing swept volume,with a permeability ratio of 6,leading to a recovery factor of only 13.84% in low-permeability layers.During the field test,the cumulative injected gas volume is 2.66×10^(4)t,cumulative oil production is 0.78×10^(4)t,and oil exchange ratio is 0.29,confirming a promising application of CO_(2) near-miscible flooding for medium-viscosity oil.
作者
张琦
朱永贤
韩天会
ZHANG Qi;ZHU Yongxian;HAN Tianhui(Research Institute of Exploration and Development,PetroChina Tuha Oilfield Company,Hami,Xinjiang 839000,China;Development Department,PetroChina Tuha Oilfield Company,Hami,Xinjiang 839000,China;Tuha Oilfield Company,PetroChina,Hami,Xinjiang 839000,China)
出处
《新疆石油地质》
北大核心
2025年第1期114-120,共7页
Xinjiang Petroleum Geology
基金
中国石油天然气股份有限公司科技项目(2023YQX10408ZK)。
