摘要
在衰竭开采中后期,近临界挥发油藏存在气体大量脱出、地层能量不足的问题。为了提高气藏采收率,在目前地层条件下(157.5℃,24 MPa),开展CO_(2)−近临界挥发油两相相平衡实验研究,在原始地层条件下(157.5℃,40.6 MPa),开展CO_(2)−近临界挥发油−地层水三相相平衡实验研究。结果表明:在近临界挥发油体系中,随着温度增加,流体体系由挥发油体系转化为凝析气体系;在CO_(2)−近临界挥发油两相体系中,随着CO_(2)的不断注入,体系的饱和压力增加,当注入CO_(2)摩尔分数达到60%后,并未发生相态反转,说明CO_(2)很好地抽提了流体中的中间烃组分和重质烃组分;在三相体系中,随着CO_(2)注入含量的增加,体系的饱和压力和溶解气油比上升;随着含水饱和度的上升,体系的饱和压力和溶解气油比降低,原油中溶解CO_(2)含量减少,并且近临界挥发油没有了临界乳光现象。研究成果为近临界挥发油藏注CO_(2)提高原油采收率提供了技术支持。
During middle and later stages of depletion production of near-critical volatile oil reservoir,there are problems of a large amount of gas escaped and formation energy insufficiency.In order to enhance gas recovery,un‑der current formation conditions(157.5℃,24 MPa),two-phase equilibrium experiment of CO_(2)-near-critical vola‑tile oil is carried out,and three-phase equilibrium experiment of CO_(2)-near critical volatile oil-water is carried out under original formation conditions(157.5℃,40.6 MPa).The results show that in near critical volatile oil system,with increase of temperature,fluid system is inverted from volatile oil system to condensate gas system.In CO_(2)-near critical volatile oil system,with continuous increase of CO_(2) injection,saturation pressure of the system increases.When CO_(2) injection reaches 60%,the phase are not inverted,showing that CO_(2) fully extracts intermediate and heavy hydrocarbon exponents.In three-phase system,with increase of CO_(2) injection,saturation pressure and dis‑solved gas-oil ratio of the system increase.With the increase of water saturation,saturation pressure and dissolved gas-oil ratio of the system decrease and dissolved CO_(2) content in crude oil decreases,and critical opalescence phe‑nomenon does not present near-critical volatile oil.The research provides technical support for CO_(2) injection to en‑hance recovery in near-critical volatile oil reservoirs.
作者
韩鑫
侯大力
赵锐
黄思婧
余洋阳
强贤宇
HAN Xin;HOU Dali;ZHAO Rui;HUANG Sijing;YU Yangyang;QIANG Xianyu(Energy College,University of Chengdu Technology,Chengdu 610059,China;State Key Laborato-ry of Petroleum Geology and Exploitation,University of Chengdu Technology,Chengdu 610059,China;Ocean Oil Production Plant of Sinopec Shengli Oilfield Branch,Dongying 257000,China)
出处
《大庆石油地质与开发》
CAS
CSCD
北大核心
2022年第6期117-123,共7页
Petroleum Geology & Oilfield Development in Daqing
基金
国家自然科学基金青年基金项目“高温高压CO_(2)−近临界挥发油−地层水三相相平衡规律表征基础研究”(51604043)。
