不同泡沫体系油藏运移特征数值模拟

Numerical Simulation of Migration Characteristics of Different Foam Systems in Oil Reservoirs

在油藏尺度下泡沫同时存在平面径向流动和垂向流动,其运移特征相比岩心流动更为复杂。为明确不同泡沫体系在油藏尺度条件下的运移特征,在室内实验结果的基础上,拟合得到准确表征泡沫体系的性能参数,采用CMGSTARS数值模拟器开展泡沫驱油藏尺度下的运移特征研究。结果表明,段塞大小不能有效提高泡沫运移距离,且段塞大小不宜超过0.4PV。强化体系受注入速度影响大,RD的变异系数高达0.57,原体系受油层厚度影响大,RD的变异系数达0.50,段塞大小、气/液比及有效浓度对各泡沫体系RD变异系数的影响相近且影响程度低,纵向渗透率和地层压力对泡沫运移及分布的影响最小。综合分析认为,原体系不适合厚油层条件使用,强化体系受发泡速度影响较大,不适合深层泡沫调驱,复配体系的发泡能力强且泡沫稳定性好,适合大部分油层条件。

At the reservoir scale,there exist both planar radial flow and vertical flow in foam,and their migration characteristics are more complex than those of core flow.In order to clarify the migration characteris-tics of different foam systems at reservoir scale,the performance parameters of foam systems are accurately characterized by fitting the laboratory experimental results,and then the migration characteristics of foam flooding in oil reservoir are studied by using the numerical simulator CMG-STARS.The results show that the slug size cannot effectively increase the foam migration distance,and it should not exceed 0.4PV.The forced foam system is affected by the injection rate greatly,and its variation coefficient of RD is as high as 0.57.The original system is affected by the reservoir thickness,and its variation coefficient of RD is 0.50.The effect of slug size,gas/liquid ratio and effective concentration on the variation coefficient of RD of each foam system are similar with low degree,while the longitudinal permeability and formation pressure have the least influence on foam migration and distribution.Comprehensive analysis shows that the original system is not suitable for the thick oil reservoirs;the forced foam is not suitable for the deep oil reservoirs because of great influence by foaming speed;and the compound system is suitable for the most oil reservoirs because of its strong foaming capability and good foam stability.