产水气藏气液两相管流动态规律研究

由于气液两相流流型的多变性和流动机理的复杂性,需要建立适用于任何流动条件的压降模型。目前工程常用的两相流压降模型主要是基于圆管流动实验数据得到的,其适用条件均具有一定的局限性。对于含水气井,其气水比一般比油井高得多,而且水和油物性差异大,气水两相流液体滑脱严重。现有的两相流压降模型用于气井压降预测时误差较大。因此对其进行了修正,给出了修正曲线。依据气水两相流实验,深入研究了气水两相上升流流动机理及特性参数变化规律,在现有气液两相流压降模型基础上探讨了适用于产水气井的H-B修正模型,应用现场资料对该模型进行的评价和验证表明,提高了预测产水气井压降分布的准确性,更符合实际情况。

Study on pressure drop models of gas-liquid two-phase pipe flow in gas reservoir

The flow pattern of gas-liquid two-phase is variable, and the flow mechanism is complex. It is necessary to seek a single model to predict pressure drop for any flow conditions. The conventional models of two-phase flow pressure drop widely used in practical engineering are mainly based on the experimental data of circular pipe flow, but their applicable conditions are limited. For the gas-producing wells containing certain formation water, gas-water ratio is usually much higher than that of oil-producing wells. The physical property of water in some aspects has some differences from that of oil, and the velocity slip between gas phase and liquid phase is serious. The flow mechanism of gas-water two-phase fluid was experimentally investigated and the variation of the special parameters of fluid flow was analyzed．On the basis of the current pressure drop model of two-phase flow, a modified pressure loss model (H-B) applicable for gas-producing wells containing formation water was proposed. The application of field data shows that the modified H-B model can improve the predictability and precision of pressure drop in water-producing gas wells.