稠油油藏水平井超临界注水井井筒物性参数预测模型

Predicting model of the physical property parameter of super-critical water injection wellbore in horizontal well of heavy oil reservoirs

常规模型不能有效表征超临界注水井井筒相态特征和高速流动条件下的温度分布特征。基于能量守恒方程和动量守恒方程,耦合油层内瞬态导热模型和吸汽模型等子模型,建立水平段井筒超临界水流动数学模型。研究认为:超临界水压力下降诱发注水井井筒温度下降、密度升高;水平段井筒中任意位置超临界水压力随温度升高而下降;水平段井筒任意位置超临界水压力随质量流速增加而减小;提高超临界水的温度和质量流速能够增加导热量、提升油层温度、降低热能吸收率;根据超临界水相态水平选取适中超临界注水温度;根据井筒—油层传质传热能力选取适中超临界水质量流速。研究结果为稠油油藏超临界注水井井筒参数预测与优选提供依据。

Conventional models cannot effectively characterize the phase characteristics of super-critical water-injection wellbore and the temperature distribution characteristics under the condition of high-velocity flow.Based on the energy conservation equation and momentum conservation equation,coupled with the sub-models such as transient heat conduction model and steam absorption model in the oil layer,the mathematical model of the super-critical water flow in the horizontal wellbore is established.The research results show that the pressure drop of the super-critical water induces the wellbore temperature drop and the density increase;at any position in the horizontal section of the wellbore,the pressure of the super-critical water decreases with the increases of the temperature;so does for the pressure of the super-critical water at any position in the horizontal section of the wellbore as the mass flow rate increases.increasing super-critical water temperature and mass flow rate can increase the amount of the heat conduction,enhance the oil layer temperature and reduce the heat absorption rate.The moderate super-critical water-injection temperature is chosen by the level of the water phase state and the moderate super-critical-water mass flow rate is selected by the wellbore-reservoir mass and heat transfer capacity.The study results provides evidences for the parameter prediction and optimization of the super-critical water-injection wellbore in heavy oil reservoirs.