CO2气井中水蒸气含量计算模型及变化规律

CALCULATION MODEL AND CHANGE LAWS OF STEAM CONTENT IN CO2 GAS WELLS

从CO2气井与天然气井的不同及CO2含量变化等问题出发，通过相应的能量守恒、传热学理论、状态方程及局部相平衡等建立相关压力、温度、湿度模型。利用模型相互关联偏差因子联立方程组求解，采用迭代计算方法和相应的数值积分方法，应用于CO2气井的井筒水蒸气含量计算。结合油藏实例进行了计算，分析了不同CO2含量及产量下水蒸气分布规律。实例计算分析表明，CO2气井井筒中，水蒸气分布规律为随着CO2含量和产量的增加水蒸气含量也呈增加的趋势。实例验证了模型的适用性，为CO2气藏开采提供了相关基础数据和理论基础。

From viewpoints of differences between C02 gas wells and natural gas wells, and changes of CO2 content etc. , through corresponding energy conservation, heat transmitting theory, state equation, partial phase equilibrium and so on, the concerned pressure, temperature and moisture models have been developed. With the help of mutual connective deviation factor of the models, the sinmhaneous equations＇ solution can be resolved ; by means of itera- tire algorithms and corresponding numerical integrating methods, the steam content in the borehole of CO2 gas wells can be calculated. Moreover, combining the actual case study, this paper conducts the above calculation and ana- lyzes the steam distribution laws under the conditions of different CO2 contents and production rates ; the analysis of above case computation shows that there are the following distribution laws： in CO2 gas well~ borehole, the steam rises with increase of COz content and water production rate. The feasibility of these models has been verified by the history cases, so the concerned basic data and theoretical base for CO2 gas reservoir production have been provided.