摘要
为明确CO_(2)吞吐过程中裂缝-基质间的流体交换特征,基于核磁共振在线扫描的CO_(2)吞吐岩心实验,从微观孔隙尺度定量表征了多轮次吞吐过程中“吞、焖、吐”3个阶段下基质内原油的动用特征,揭示了裂缝-基质之间的流体交换特征。结果表明,每轮吞吐采收率随吞吐次数的增加而降低,其中大孔隙(2 ms<T2≤100 ms)动用程度最大,对岩心总采收率的贡献程度最高达84.4%,是致密油藏未来挖潜的主要方向。焖井和衰竭两阶段的采出程度占总采收率的87%以上,增大焖井和衰竭降压2个阶段中大孔隙原油的动用程度是提高CO_(2)吞吐开发的关键。
In order to clarify the fluid exchange characteristics between fractures and matrix during CO_(2)huff-puff,core experiments of CO_(2)huff-puff were carried out based on NMR online scanning.The producing characteristics of crude oil in the matrix in three stages"inhalating,soaking and discharging"of each huff-puff cycle were studied from the micro pore scale,and the fluid exchange characteristics between fractures and matrix were quantitatively described.The experimental results show that with the increase of huff-puff cycles,the recovery degree of crude oil in single huff-puff cycle decreases;the recovery degree of crude oil in large pores(2 ms<T2≤100 ms)is the largest,whose contribution degree to the total recovery degree can reach to 84.4%,and the crude oil in the large pores is main potential of fractured tight sandstone reservoir in the future.The recovery degree of crude oil in well soaking and depletion stage accounts for more than 87%of total recovery degree.The key to improve the recovery rate of CO_(2)huff-puff development of fractured tight sandstone reservoir is to increase the utilization of the crude oil in large pores in two stages of well soaking and depletion depressurization.
作者
刘国华
LIU Guohua(Engineering Technology Research Institute,PetroChina Great Wall Drilling Company,Panjing,Liaoning 124010,China)
出处
《西安石油大学学报(自然科学版)》
北大核心
2021年第5期64-70,76,共8页
Journal of Xi’an Shiyou University(Natural Science Edition)
基金
国家十三五科技重大专项“大型油气田及煤层气开发”(2016ZX05060)。
关键词
CO_(2)吞吐
流体交换
裂缝
微观孔隙
致密油藏
核磁共振
CO_(2)huff-n-puff
fluid exchange
fracture
micro pore
tight reservoir
nuclear magnetic resonance