Abstract:

A pilot-scale reactor with a volume of 196L was adopted to examine the decomposition behavior of hydrate reservoir which contains a bottom gas-rich zone. Exploitation experiments with a single vertical well, and with double well (vertical and horizontal well) were conducted. Results showed that an excessive pressure drop might result in well blocking by the ice which was resulted from foam entrainment. For reservoir with a bottom gas-rich zone, the areas closer to the well and the bottom of the reactor had a greater temperature drop, compared to other areas of the reactor owing to the faster local gas flow rate. The classical decomposition dynamics model was established. Results showed that for the large three-dimensional device, the driving force and decomposition rate could not reflect the actual hydrate decomposition behavior accurately. However, after the driving force was corrected through the residual ration of hydrate, the driving force had a linear relationship with the decomposition rate, and fitting parameters of single well experiment that k=0.284mol/(min·MPa) and double well experiment that k=0.279mol/(min·MPa) can be mutually verified.

Key words: hydrate, exploitation, decomposition dynamics, pilot-scale device

摘要：

利用196L三维装置研究了含下伏气层水合物藏的降压分解规律。对比研究了单竖直井实验和竖直井-水平井双井开采的实验，实验结果表明，过大的降压幅度可能会导致开采井被雾沫夹带的水堵塞，对于含下伏气层的水合物藏，反应釜底部和近井区域由于局部气流速度过快导致更严重的温降。建立了经典格式的分解动力学模型，结果表明，对于三维装置，单独利用推动力和分解速率并不能准确反映水合物实际分解状况。利用水合物剩余分解比例校正后，推动力和分解速率呈线性关系，单井实验所拟合参数k=0.284mol/(min·MPa)与双井降压实验 k=0.279mol/(min·MPa)可以互相验证。

关键词: 水合物, 降压开采, 分解动力学, 中试装置