火烧油层注气加热过程的模拟计算研究

在火烧油层的注气加热过程中，需要根据点火需求优化注气参数。考虑了空气在井筒、油层的流动及换热过程，包括空气进入油层的混合过程、水蒸发进入空气和湿空气降温后凝结为水的组分及相态变化、油层之间的导热过程，建立了相应的瞬态模型，提出了基于龙格库塔法的求解方法。利用该模型及求解方法进行了模拟注气验证，并用于油田的实际火烧油层点火过程的监测系统。研究表明：点火过程中加热带扩展速度非常有限（6 d 后加热带半径仍小于0.6 m），并且受油层中含水率影响较大，加热带温度主要受电加热器功率和注气速度影响，受注气时间长短影响较小。点火过程中应保持电加热器功率和注气速度稳定。

Simulation of Gas Injection-Heating Process of In Situ Combustion

It is necessary to optimize the parameters of gas injection heating during the gas injection-heating process in situ combustion. A transient model is proposed to simulate the flow and the heat exchange of air in the well tube and oil reservoirs including the mixing process of air and oil reservoirs,change of component and phase state such as evaporation of hot water and condensation of cold wet air,the heat exchange among different oil reservoirs and rock. A solving method based on Rung- Kutta and a simulation program is programmed. After the verification of simulating injection,this mathematical model and its solving method are applied to the simulation and monitoring of gas injection heating process in situ combustion at actual oil field. It was found that the extension of heating zone is slow (radius of heating zone is less than 0.6 m after a 5-day injection) and greatly influenced by the moisture content of oil reservoir,and the temperature of it is almost constant and determined by the power of electric heater and gas flow rate. The power of electric heater and gas flow rate should keep in a stable state during the heating process.