摘要
与混相驱相比,CO_2近混相驱在驱油效率方面有所下降,但由于压力降低后流度改善、波及效率提高,最终采收率并未明显下降。考虑到近混相驱在气源和操作成本方面的优势,CO_2近混相驱受到越来越多的关注。中国渤海油田秦皇岛区块勘探开发过程中发现了大量富含CO_2(24mol%~90mol%)的产出气,为实施非纯CO_2近混相驱提供了条件。采用加密细管实验和模拟点的方法,确定了不同CO_2含量(100%、85%、80%、70%、55%、40%、24%和0)下近混相压力的区间,获得了目标油藏典型井实现近混相驱的CO_2含量下限为64.13%。在此基础上,为扩大近混相驱的范围和潜力,针对含量下限之下的CO_2(55%、40%和24%),探索了添加轻质组分C_2~C_6对近混相压力区间的影响程度,获得了不同CO_2含量下实现近混相驱所需的轻质组分C_2~C_6含量以实现对目标油藏CO_2近混相驱优化和调控的目的。
Compared with miscible flooding,the displacement efficiency of the CO_2 near-miscible flooding declines to a certain extent,but the final recovery is very close because the mobility and sweep efficiency improve with the pressure decreases. Considering the advantages of near-miscible flooding in gas source and operation cost,it has attracted more and more attention recently. During the exploration and development of Qinhuangdao Oilfield in Bohai,the discovery of a big natural gas sources with varying CO_2 content( 24 mol% ~ 90 mol%) just on top of the oil layer,provides big potential for the production gas re-injection to develop the oilfield effectively. In this paper,slim tube test and slim tube simulation were conducted to determine the pressure interval of near-miscible flooding under different CO_2 content( 100%,85%,80%,70%,55%,40%,24% and 0). The lower CO_2 content for achieving near-miscible flooding is 64. 13% for the targeted reservoir. On this basis,to expand the scope and the potential of the near-miscible flooding,light components of( C_2~ C_6) were added for the CO_2 content of 55%,40% and 24% to study the impact on the pressure range of near-miscible flooding. Moreover,the amount of( C_2~ C_6) needed for achieving near-miscible flooding under different CO_2 contents was forecasted. Thus,the optimization and control of near-miscible flooding in the targeted reservoir by adding light components was studied.
出处
《科学技术与工程》
北大核心
2018年第1期12-17,共6页
Science Technology and Engineering
基金
海洋石油高效开发国家重点实验室开放基金(2015-YXKJ-001)
中国石油大学(北京)科研基金(2462013YXBS003)资助
关键词
CO2驱
最小近混相压力
非纯CO2
近混相驱调控
CO_2 flooding
minimum near-miscible pressure
impure CO_2
near miscible flooding control
