泡状流中水合物生成预测模型及实验

针对可燃冰钻采井筒内易发生水合物生成和堵塞的工程问题，本文开展了泡状流条件下甲烷水合物生成实验，发现流速增加会提高水合物生成速率，黄原胶质量分数的增加会降低水合物生成速率。基于传质理论，构建了适用于可燃冰钻采井筒内泡状流条件下水合物生成预测模型，模型考虑了连续相流体流变性、气泡破裂、聚并和形变等因素对泡状流中气液界面分布和气液间传质规律的影响，并耦合实验数据，提出了气泡群间的综合传质系数经验公式，用于描述气泡间相互作用对气液间传质速率的影响。对比实验结果，所建立模型对水合物生成量和水合物生成速率的预测误差分别在±5%和±15%以内，满足工程计算需求。该模型的构建有助于精准预测油气和可燃冰钻采井筒内水合物风险，为建立经济、高效的井筒水合物防治方案奠定理论基础。

Prediction model of hydrate formation in bubbly flow and experimental study

Considering the risks of hydrate formation and plug in the gas hydrate wellbore, experiments were conducted to investigate methane hydrate formation in bubbly flow using flow loop. Experimental results showed that the increases of flow velocities enhance the hydrate formation rates but the increases of xanthan gum concentrations reduced the hydrae formation rates. Based on gas-liquid mass transfer mechanism, a hydrate formation prediction model in bubbly flow was developed considering the influences of rheology of continuous-phase, and the breakage, coalescence and deformation of gas bubbles on the gas-liquid interfacial area and the gas-liquid mass transfer rate. Coupling with experimental data, an empirical formula of the overall mass transfer coefficient was proposed to describe the effect of interactions between gas bubbles on the gas-liquid mass transfer rates. Compared with experimental data, the developed model predicted the quantity of hydrate formation and the hydrate formation rate with the discrepancies within ±5% and ±15% respectively. The developed model contributed to forecast the hydrate risk in the oil, gas and natural gas hydrate wellbore and laid a theoretical foundation for developing an efficiency and economic hydrate management plan in wellbore.