Experimental investigation of gaseous solvent huff-n-puff in the Middle Bakken Formation  

作　　者：Samuel Asante Afari Kegang Ling Demetrius Maxey Billel Sennaoui Jerjes Hurtado Porlles 

机构地区：[1]Department of Petroleum Engineering,University of North Dakota,2844 Campus Rd,Stop 8154,Grand Forks,ND,58202-6116,USA

出　　处：《Petroleum Science》2023年第6期3488-3497,共10页石油科学（英文版）

摘　　要：The efficacy of gaseous solvents in enhancing oil recovery(EOR)in unconventional reservoirs and the influence of operational and design parameters are still debated among the oil recovery research community.This work investigated the recovery-enhancing capabilities of two potent gaseous solvents,CO_(2) and ethane,in tight core samples.Laboratory huff-n-puff(H-n-P)experiments were conducted under three miscibility conditions to investigate the influence of the key operating parameters and the dependency of their impact on the miscibility conditions and gas composition.The results show that oil recovery increased with increasing pressure from below(BM)to above(AM)miscibility pressure in a non-linear trend,irrespective of the gas composition.Furthermore,the influence of the soak period was noticeably dependent on the miscibility condition,specifically more remarkable under AM conditions and less apparent under BM conditions.Likewise,the effect of the production period was more pronounced at AM conditions for both gases.Finally,the impact of rock surface area-to-volume(SA/V)was only observed at BM,where both gases recovered more oil in the core samples with high SA/V.In general,ethane showed a higher efficacy for oil recovery than CO_(2);CO_(2) recovered 21%–70%of oil in small core samples,while ethane could recover 32%–88%.The highest recovery was achieved with ethane injected under AM conditions,with a prolonged soak time,a short production period and into a core sample with a high SA/V.We believe the findings from this work will help better understand and design H-n-P EOR projects.

关 键 词：Unconventional reservoirs Huff-n-puff Gas solvent ETHANE CO_(2)miscibility 

分 类 号：TE357[石油与天然气工程—油气田开发工程]