摘要
为深化研究尺度效应对天然气混相驱驱油效果的影响,以中原油田某区块沙三中低渗挥发性油藏为例,分别采用不同长度组合天然岩心开展小尺度天然气驱物理模拟实验,揭示了长岩心混相驱提高采收率机理,并以实际地质模型为原型采用数值模拟方法进一步研究大尺度下的气驱开发效果,研究结果表明:长度分别为1 800 mm、950 mm、500 mm的岩心天然气驱采收率分别为90.88%、82.89%、64.8%,长岩心较短岩心的驱油效率提高了25%左右,即同一注入速度下,随着注入量的增加,长岩心混相段较长,多次混相接触较充分,气体突破时间滞后,同时通过数模证实存在最佳注采井距范围300~350 m,在此井距范围内注采井距越大驱替效果越好,随着井距的继续增大,采收率增幅越来越小,经济效果变差。通过研究,进一步明确了尺度效应对天然气驱油效果的影响,对该区块注采参数优化及同类油藏的开发具有重要的现实指导意义。
In order to study the influence of the scale effects on the oil displacement efficiency of natural gas miscible-flooding,we proposed to take the volatile reservoir with mid-low permeability of the third section of the Shahejie formation of some block in Zhongyuan oilfield as an example,and carried out the small scaled physical simulation experiment of natural gas flooding by the combination of natural cores with different length to revealed the mechanism of enhanced oil recovery by long core miscible flooding.And then we researched the gas driving development effects with large size by the numerical simulation method based on the actual geological model.The results show that the recovery rate of the natural gas recovery with the core length of 1 800 mm,950 mm and 500 mm respectively are 90.88%,82.89%and 64.8%.It is found that the oil displacement efficiency of the long core is about 25%higher than that of the short one,that is to say,along with the increase of the injection volume at the same injection rate,the miscible section of the long core is longer,the miscible contact is sufficient and there are time lags in gas breakthrough.Meanwhile,it is verified by numerical simulation that the best well spacing range is 300~350 m.Within this range,the larger the well spacing is,the better the displacement effect will be.But as the well spacing increases,the increasing degree of the recovery efficiency and the economic effect all get worse.Based on this study,the influence of size effect on natural gas displacement is further clarified,which is of great practical significance for the optimization of injection and production parameters and the development of similar reservoirs.
作者
杨雪
Yang Xue(Research Institute of Exploration and Development of Zhongyuan Oil Field Company,SINOPEC,Puyang,Henan 457000,China)
出处
《油气藏评价与开发》
CSCD
2018年第5期37-41,共5页
Petroleum Reservoir Evaluation and Development
基金
中国石化重大科技先导试验项目"文南油田注天然气驱"先导试验(P03005)
关键词
尺度效应
混相驱
采效率
长岩心
数值模拟
scale effect
miscible displacement
recovery efficiency
long core
numerical simulation
