巨厚气藏气井井筒压力计算模型及应用——以普光气田为例

针对目前常用定质量流井筒压力计算模型不适用于产层段井筒长、从底部至顶部质量流量变化大的巨厚气藏气井的问题，通过耦合气井流入状态和井筒管流，建立了巨厚气藏气井产层段变质量流井筒压力计算模型，并通过实例气井进行验证，同时将该模型应用于气井产能评价。结果表明：变质量流模型计算的井筒压力值比定质量流模型小，两者之间差异随产气量和产层段长度增加而增大；在产层段不同深度处，变质量流模型计算误差均小于2%,计算精度较高。该变质量流模型能较精确地计算井筒压力值，进而可以有效解决气井产能测试遇阻无法获得井筒压力、井筒压力折算值不准确易导致产能指示曲线负异常等问题。该研究对巨厚气藏气井井筒压力分布计算和产能评价能够提供强有力技术支撑。

Calculation model of wellbore pressure and its application for gas wells in ultra-thick gas reservoirs

The commonly used wellbore pressure calculation model with constant mass flow is not suitable for gas wells in ultra-thick gas reservoirs with long production intervals and large mass flow changes from the bottom to the top. In order to solve this problem, the calculation model of wellbore pressure with variable mass flow in the production interval of gas wells in ultra-thick gas reservoir is established by coupling the inflow state of the gas well and the wellbore tube flow. Subsequently, this model is verified by an example gas well, and then it is applied to the evaluation of gas well productivity. The results show that wellbore pressure calculated by variable mass flow model is smaller than that of constant mass flow model, and the difference between them grows with the increase of gas production and the length of the production interval. In addition, at different depths of the production interval, the calculation errors of variable mass flow model are all less than 2%, indicating high calculation accuracy. Variable mass flow model can calculate wellbore pressure more accurately, and then can effectively solve the problems such as failure to obtain wellbore pressure when gas well productivity test is blocked, and the inaccurate wellbore pressure conversion that can easily lead to negative abnormality of the productivity indication curve. This study provides significant technical support for the calculation of wellbore pressure distribution and productivity evaluation of gas wells in ultra-thick gas reservoirs.