Quantification of a Single Gas Bubble Growth in Solvent(s)-CO2-Heavy Oil Systems With Consideration of Multicomponent Diffusion Under Nonequilibrium Conditions
Quantification of a Single Gas Bubble Growth in Solvent(s)-CO2-Heavy Oil Systems With Consideration of Multicomponent Diffusion Under Nonequilibrium Conditions
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DOI：
10.1115/1.4035150
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发表时间：
2017-03-01
影响因子：
3
通讯作者：
Yang, Daoyong
中科院分区：
文献类型：
--
作者：
Shi, Yu;Yang, Daoyong
考虑非平衡条件下多组分气体在溶剂-CO2-重油体系中的扩散，建立了一个量化单个气泡生长的机理模型，并进行了验证。实验方面，分别在平衡和非平衡条件下对C_3H_8-CO_2-重油体系进行了恒组分膨胀实验。在理论上，将经典的连续性方程、运动方程、扩散-对流方程、真实的气体方程和Peng-Robinson状态方程（PR EOS）整合成一个方程矩阵，对气泡生长进行动态预测。同时，由于稠油的粘性，在运动方程中考虑了粘性项对气相压力的影响。利用实验测量的气泡半径作为时间的函数，验证了新提出的模型具有良好的准确性。结合实验结果，对临界核半径和气泡生长进行了定量预测。考察并分析了传质、过饱和压力、各组分摩尔浓度、液池半径和压力下降速率对气泡生长的影响。在一般情况下，气泡的生长速率被发现与上述五个参数中的每一个的增加，虽然在气体混合物中的单个组分的气泡生长速率的贡献是不同的。一步压降和气泡周围无限大的液体体积被认为是气泡半径与时间平方根之间产生线性关系的必要条件。
A mechanistic model has been developed and validated to quantify a single gas bubble growth with considering multicomponent gas diffusion in solvent(s)-CO2-heavy oil systems under nonequilibrium conditions. Experimentally, constant-composition expansion (CCE) experiments are conducted for C3H8-CO2-heavy oil systems under equilibrium and nonequilibrium conditions, respectively. Theoretically, the classic continuity equation, motion equation, diffusion-convection equation, real gas equation, and Peng-Robinson equation of state (PR EOS) are integrated into an equation matrix to dynamically predict gas bubble growth. Also, the viscous term of motion equation on the gas phase pressure is included due mainly to the viscous nature of heavy oil. The newly proposed model has been validated by using the experimentally measured gas bubble radius as a function of time with good accuracy. Combining with the experimental measurements, the critical nucleus radius and gas bubble growth are quantitatively predicted with the newly proposed model. Effects of mass transfer, supersaturation pressure, mole concentration of each component, liquid cell radius, and pressure decline rate on the gas bubble growth are examined and analyzed. In general, gas bubble growth rate is found to increase with an increase of each of the aforementioned five parameters though the contribution of individual component in a gas mixture to the bubble growth rate is different. A one-step pressure drop and the unlimited liquid volume surrounding a gas bubble are considered to be the necessary conditions to generate the linear relationship between gas bubble radius and the square root of time.