CO₂注入井井筒温压场计算及参数敏感性分析

CO₂ Injection Wellbore Temperature-Pressure Field Calculation and Parameter Sensitivity Analysis

摘要: 为完善CO₂注入井井筒温压场预测方法，解决现有模型计算繁琐、敏感性分析缺乏多因素协同的问题，本文采用井筒温压耦合计算模型，通过Python调用CoolProp高精度物性数据库获取CO₂热物性参数，结合现场CO₂试注井实例开展模型验证，并系统分析注入参数的单因素与多因素协同敏感性。结果表明：所用耦合模型预测值与现场实测数据吻合度高，温度、压力相对误差分别为5.6%、2.1%，具备较高的计算精度；单一参数敏感性分析显示，注入温度与注入排量是井筒温度场的关键调控参数，注入压力仅主导压力场分布，且注入温度、排量对压力场无显著影响；多参数协同分析表明，注入排量对注入温度的温度场调控效应存在放大作用，排量越高，注入温度对井筒温度场的影响深度越大。研究成果为CO₂地质埋存工程中注入参数优化设计及井筒安全运行提供了理论依据与技术支撑。

Abstract: To improve the prediction method for the temperature and pressure fields of CO₂ injection wellbores and address the problems of cumbersome calculations in existing models and the lack of multi-factor synergy in sensitivity analysis, this study adopts a wellbore thermo-pressure coupling calculation model. Python is used to invoke the high-precision CoolProp physical property database to obtain the thermophysical parameters of CO₂. Model validation is carried out combined with field CO₂ pilot injection well cases, and the single-factor and multi-factor synergistic sensitivity of injection parameters are systematically analyzed. The results show that the predicted values of the adopted coupling model are in high agreement with the field measured data, with relative errors of 5.6% for temperature and 2.1% for pressure, indicating high calculation accuracy. Single-parameter sensitivity analysis reveals that injection temperature and injection rate are the key controlling parameters for the wellbore temperature field, injection pressure only dominates the pressure field distribution, and injection temperature and rate have no significant effect on the pressure field. Multi-parameter synergistic analysis demonstrates that injection rate has an amplifying effect on the temperature field regulation effect of injection temperature; the higher the injection rate, the greater the influence depth of injection temperature on the wellbore temperature field. The research findings provide a theoretical basis and technical support for the optimal design of injection parameters and safe wellbore operation in CO₂ geological sequestration projects.