深井井筒气液两相流的数值研究

Numerical Study on Gas-Liquid Flow in the Wellbore of Deep Wells

综合考虑温度、压力对钻井液物性的影响,本文建立了气侵时深井钻井环空中气液两相流动的水力和热力模型,并采用所建立的模型对5000 m深井的水力、热力特性进行了计算与分析。计算结果表明,气侵量对井底压力影响很大,对于本文所研究的情况,气侵量从0.1 m^3/s增加到2.0 m^3/s时,井底压力降低了10.6 MPa。研究还表明,不同的井口回压对于井底压力有较大的影响,当井口回压每增加0.5 MPa时,井底压力增加1 MPa左右。

A gas-liquid mechanical model as well as a thermal model which consider the effect of the temperature and pressure on properties parameters are established for the annulus flow in the deep well in this paper. Afterwards, with the models, the hydraulic and thermal characteristic of a well with a depth of 5000 m is analyzed. Results show that gas kick has significant impacts on the bottomhole pres- sure. For the studied case, the bottomhole pressure decreases by 10.6 MPa with the gas kick increases from 0.1 m3/s to 2.0 m3/s. Besides, the study also indicates that the wellhead back pressure affects bottomhole pressure obviously, with a 0.5 MPa rise of the former induces a i MPa increase of the latter.