砾岩油藏CO2混相驱提高采收率实验及应用评价
Experiment and application evaluation of enhanced oil recovery of conglomerate reservoir by CO2 miscible flooding
张晶晨 1李杰 1张文 1盛国荣 1董海海1
作者信息
- 1. 中国石油新疆油田公司勘探开发研究院,新疆 克拉玛依 834099
- 折叠
摘要
为了研究砾岩油藏水驱后CO2混相驱提高采收率机理及现场应用效果,以新疆油田M井区克下组砾岩油藏为例,通过开展细管、核磁共振、岩心驱替实验,对CO2-原油最小混相压力、孔隙尺度下CO2混相驱微观特征、岩心尺度下CO2混相驱影响因素开展研究,并对现场注气试验效果进行评价.结果表明:M井区克下组砾岩油藏CO2 驱最小混相压力为24.1 MPa;油藏水驱后的CO2混相驱主要动用孔隙半径大于0.5 μm的中孔、大孔内的剩余油,分别提高采收率8.52、26.03百分点;在混相条件下,CO2 注入速度为0.5 mL/min时提高采收率最高,可达35.89百分点,推荐矿场单井注气速度为18 t/d;采用段塞尺寸0.3 PV分4轮次水气交替注入,最终采收率最高为79.25%.现场试验评价显示:M井区克下组砾岩油藏注气适应性强,储层视吸气指数升高至1.0 t/(d·MPa),油井见效比例超过60%,其中45%的见效井初步实现混相驱;油井压裂引效措施增产效果明显,累计增油量为4 174 t,平均单井日增油量为3.5 t.研究成果可为M井区后续CO2混相驱工业化开发提供有效指导.
Abstract
In order to study EOR enhancement mechanism and field application effect of CO2 miscible flooding after water flooding in conglomerate reservoir,taking conglomerate reservoir of Lower Karamay Formation in M well block of Xinjiang Oilfield as an example,slim tube,nuclear magnetic resonance and core displacement experi-ments are carried out to study the minimum CO2-oil miscible pressure,microscopic characteristics of CO2 miscible flooding at pore scale and influencing factors of CO2 miscible flooding at core scale,and to evaluate the effect of field gas injection test.The results show that the minimum miscible pressure of CO2 flooding in conglomerate reser-voir of Lower Karamay Formation in M well block is 24.1 MPa.CO2 miscible flooding after water flooding mainly pro-duces residual oil in mesopores and macropores with pore radius>0.5 μm,with recovery increased by 8.52 and 26.03 percentage points respectively.In miscible condition,when CO2 injection rate is 0.5 ml/min,the maximum incremental recovery reaches 35.89 percentage points,and recommended single-well field gas injection rate is 18 t/d.With 0.3-PV slug and 4 rounds of water-gas alternating injection,ultimate recovery reaches the maximum of 79.25%.Field test evaluation shows that conglomerate reservoir in Lower Karamay Formation of M well block is adaptable for gas injection,with apparent gas adsorption index of reservoir increasing to 1.0 t/(d·MPa),and pro-portion of response wells exceeds 60 percent,among which 45%of response wells preliminary achieve miscible flooding.Well fracturing gets obvious stimulation effect,with cumulative incremental oil of 4 174 t and average dai-ly single-well incremental oil of 3.5 t.The research provides effective guidance for subsequent commercial develop-ment of CO2 miscible flooding in M well block.
关键词
砾岩油藏/CO2驱油/混相驱/提高采收率/注气效果评价Key words
conglomerate reservoir/CO2 displacing oil/miscible flooding/enhanced oil recovery/gas injection ef-fect evaluation引用本文复制引用
出版年
2025
国家科技期刊平台
NSTL
万方数据