轻质油藏空气驱低温氧化数值模拟研究

Numerical simulation of low temperature oxidation for air in the light reservoir

通过注空气的室内实验和数值模拟方法研究油层温度场分布特征、含氧剖面、原油性质变化、产出气体组成、采收率等进一步分析低渗油藏注空气驱油机理。研究表明:低温氧化过程热效应相当明显,形成稳定的高温剖面,最高温度达到460℃;氧气被逐渐消耗,氧气浓度由21%逐渐降到0,含氧剖面由注入井逐渐向生产井推进;产生的N2、CO2和CO含量高达97%,气体突破前原油中重质组分和中间组分的含量逐渐减少,轻质组分的含量逐渐增加,部分原油轻质组分被气体所抽提,表现出烟道气驱的特征;当注入1.8PV空气时,采收率可达到47.23%,再进行注空气,增产效果已不明显,可以考虑气水交替或空气泡沫驱油。

In order to study the mechanism of air injection for enhancing oil recovery in the low permeablity oil reservoirs,Laboratory experiments and reservoir simulation of the air injection were carried by researching of temperature distribution characteristics,oxygen profiles,output gas composition and recovery etc.The result shows that temperature of oxidation process is obvious and stable temperature profile is formed.the highest temperature reached 460℃ and the percentage of oxygen decreased from 21% to 0 when oxygen profile by injection Wells section to production Wells.The percentage of N2,CO2 and CO in the production gas reaches as high as 97%.Before the breakthrough,heavy and intermediate components gradually reduce while light weight components increase gradually.Light weight components in part of crude oil were extracted,showing the characteristics of flue-gas flooding.When 1.8 PV air is injected,recovery can reach 47.23%.and then the effects of increasing recovery has not obvious keeping on injecting.we can consider the alternating water and gas or air foam flooding.