摘要
致密油藏体积改造压后闷井过程中发生的渗吸置换,通常在压差(基质外部流体压力与孔隙压力之差)作用下进行,但渗吸置换物理模拟却通常在常压下进行(即自发渗吸),带压条件下的渗吸置换特征尚未提及。为研究压差作用下的渗吸置换(即带压渗吸)规律,首先,建立基于低场核磁共振测试技术的带压渗吸实验方法;其次,分析自发/带压渗吸的异同;最后,建立带压渗吸无因次时间模型。结果表明,质量分数为96.76%~97.25%的油相集中分布于纳米孔(1 ms≤T2≤100 ms)内,纳米孔是主要储集空间;相比于自发渗吸,带压渗吸置换效率大幅提升是由强化的渗吸作用和压实作用共同造成的;岩心尺度建立的带压渗吸无因次时间模型可行,为确定油藏尺度压后闷井时间提供了新思路。
Spontaneous imbibition(SI)generally occurs under forced pressure(pressure difference between hydraulic fluid pressure and original pore pressure)during a shutin period.However,the experimental study of SI is commonly performed at atmospheric pressure and the effect of forced pressure is often neglected.In this study,the mechanism of SI in tight sandstone samples under forced pressure(forced imbibition,FI)was studied.A new experimental method for forced imbibition was firstly constructed based on lowfield nuclear magnetic resonance(LF-NMR)measurements.After that,a correlation between SI and FI was discussed.Finally,a new dimensionless time model considering the effect of forced pressure for FI was constructed.The results showed that 96.76%-97.25%wt%of the oil was distributed in nanopores(0.1 ms≤T2≤100 ms)of core samples,occupying the major pore space.The ultimate oil recovery for FI was significantly improved relative to that of SI,which was associated with the synergetic effect of enhanced SI and compaction.The new dimensionless time model for FI was proved to be effective and it provides a new method to calculate shutin time at field scale.
作者
江昀
许国庆
石阳
余玥
王天一
曾星航
郑伟
JIANG Yun;XU Guoqing;SHI Yang;YU Yue;WANG Tianyi;ZENG Xinghang;ZHENG Wei(PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;SINOPEC Research Institute of Petroleum Engineering,Beijing 100101,China;PetroChina Southwest Oil&Gas Field Company,Chengdu,Sichuan 610056,China)
出处
《石油实验地质》
CAS
CSCD
北大核心
2021年第1期144-153,共10页
Petroleum Geology & Experiment
基金
国家科技重大专项“致密油储层高效体积改造技术”(2016ZX05046-004)资助。
