CO2对超稠油物性影响的实验研究

Effect of CO2 on Physical Properties of Super Heavy Oil

吴光焕 夏志增 时凤霞 吴海君 李 军

WU Guanghuan XIA Zhi-Zeng SHI Fengxia WU Hai-Jun LI Jun

为研究CO2辅助蒸汽吞吐技术开发超稠油中CO2的作用，以郑411区块超稠油为研究对象，通过注气膨胀实验系统地研究了不同CO2注入量、温度及压力下，超稠油物性的变化规律，并使用多元回归方法分别建立了溶解气油比、饱和压力、原油黏度、原油密度及原油体积系数与CO2注入量、温度及压力的关系模型，拟合优度在均在0.90以上。郑411块超稠油的溶解气油比随CO2注入量的增加而线性增加；饱和压力随CO2注入量的增加而线性增加，随温度增加而呈乘幂趋势增加；原油黏度随CO2注入量增加而呈指数趋势降低，其对数值随温度升高呈乘幂趋势降低；原油密度随CO2注入量增加呈指数趋势降低，随温度升高呈对数趋势降低，随压力增加而线性增加；原油体积系数随CO2注入量和温度的增加均呈指数趋势增加，随压力增加而线性减小。超稠油对温度有极强的敏感性，加热升温能显著降低超稠油黏度，提高其流动性；同时，CO2溶解降黏、膨胀原油的特性，能改善原油物性，有助于超稠油的动用。

In order to probe the effect of CO2 on super heavy oil in CO2 assisted steam huff and puff technology, physical properties of super heavy oil in Zheng 411 reservior under different amount of CO2 injection, different pressures and different tempretures were studied through gas injection swelling tests systematically, and predictive models for solution gas-oil ratio, bubble point pressure, oil viscosity, oil density and volume factor with CO2 content, pressure and temperature were established by means of multiple regression with high accuracy. The results showed that the solution gas oil ratio of the studied super heavy oil increased with the increase of the CO2 content linearly; the bubble point pressure increased with the increase of the CO2 content linearly, and increased with the increase of the temperature in a strong power relation; the oil viscosity decreased with the increase of the CO2 content exponentially, the natural logarithm of which decreased with the increase of temperature exponentially; the oil density decreased with the increase of the CO2 content exponentially, and decreased with the increase of temperature logarithmically, while increased with the increase of pressure linearly; the volume factor increased with the increase of the CO2 content exponentially, and increased with the increase of temperature exponentially, while decreased with the increase of pressure linearly. The viscosity of super heavy oil is very sensitive to temperature, and the oil mobility will be improved with the increase of temperature. Besides, dissolved CO2 can reduce the oil viscosity and swell the oil, which is helpful for the production of super heavy oil.