低黏原油辅助气体吞吐稠油开采技术室内实验和技术界限

Indoor Experiment and Technical Boundary of Heavy Reservoir with Gas Huff and Puff Assisted by Low-Viscosity Oil Injection

稠油蒸汽吞吐后期及蒸汽驱的油汽比仅为0.1~0.2,能耗大、碳排量高等问题突出,针对该问题,可利用低黏原油辅助气体吞吐的开采方法来改善开发效果。通过室内模拟实验和油藏数值模拟,开展低黏原油辅助气体吞吐开采稠油的机理及油藏适应性研究,制订低黏原油辅助气体吞吐的技术界限。研究表明:低黏原油辅助气体吞吐开采机理主要为稀释降黏、溶解增压、扩大波及范围和乳化相变等作用,带油率(采出稠油与注入低黏原油的体积比)可达到1.00~3.00以上,且能耗低、产水少;低黏原油辅助气体吞吐适合开采普通稠油油藏和特稠油油藏,尤其适合深层、薄互层和小断块稠油油藏。该研究对稠油转换低黏原油辅助气体吞吐开发油藏筛选和工程设计具有指导意义。

In the late stage of steam huff and puff or steam flooding for the heavy oil reservoir,the oil-steam ratio is only 0.1 to 0.2,which leads to high energy consumption and carbon emissions.To address the issue,a recovery method that utilizes low-viscosity oil injection assisted heavy reservoir with gas huff and puff has been proposed to improve the development effect.Through indoor test and reservoir numerical simulation,the mechanism and applicability are studied,and the technical boundary are delimited.The study shows that the mechanism of heavy reservoir with gas huff and puff assisted by low-viscosity oil injection is mainly viscosity reduction by dilution,solution gas drive,swept volume expansion and facies change by emulsification.The oil-carrying rate(volume ratio of produced heavy oil to injected low-viscosity oil)can reach 1.00-3.00,and the energy consumption and the water production is low.The new method is suitable for conventional heavy oil reservoirs and extra-heavy oil reservoirs,especially for deep zones,thin interbedded and small fault blocks.This study has guiding significance for reservoir screening and engineering design of heavy reservoir with gas huff and puff assisted by low-viscosity oil injection.