稠油注天然气混合密度变化规律研究及模型建立

Study and model establishment on variation law of mixed density during natural gas injected into heavy oil

关键词:  超稠油  注天然气  高温高压  混合密度  计算模型

Key words:  ultra-heavy oil  natural gas injection  high temperature and high pressure  mixture density  calculating model

摘要:

稠油注气后的密度改变直接影响举升效率,为了提高塔河稠油开采效益,针对塔河油田超稠油开展了稠油注天然气混合密度研究。结果 表明:稠油注天然气后混合密度随温度升高、注气比增加而降低,近似呈线性关系。在实验基础上,对应用较广泛的原油注气密度计算Obomanu模型进行了修正,建立了塔河原油注天然气密度模型；Obomanu模型的相关系数R²为0.670 3~0.769 2,修正模型的相关系数R²为0.985 2~0.998 9,修正后的密度模型拟合度提升了30%左右,适用于低压和高压环境；建立了原油注天然气平衡压力-原油密度-平衡气油比关系图版,可指导稠油注天然气开采。 

Abstract:

The density change of heavy oil after injecting gas influences the lifting efficiency directly. In order to improve the production efficiency of Tahe heavy oil, the study of mixed density of natural gas injected into super heavy oil in Tahe oilfield was carried out. The results showed that the mixing density decreases quasi-linearly with the increase of temperature and oil-gas ratio. Based on the experimental data, the Obomanu model of calculating heavy oil-gas mixture density is modified, and the density model of Tahe crude oil with gas injection is established. The correlation coefficient R² of Obomanu model is 0.670 3-0.769 2, the correlation coefficient R² of modified model is 0.985 2-0.998 9, the fitness degree of modified model is enhanced by 30%, which is suitable for low and high pressure conditions. The balance pressure-density-gas oil ratio map of oil-gas mixture is established, and it can guide the gas production with heavy oil injection.