高含硫气井中的硫沉积规律

针对高含硫气井井筒硫析出、硫沉积预测难题,建立了高含硫气井井筒多相流动和传热数学模型,给出了多场耦合井筒硫析出、硫沉积判别准则和计算方法。计算结果表明,高含硫气井从井底至井口硫溶解度逐渐减小,呈非线性变化规律;井筒中伴随有硫析出,析出位置及析出量主要受温度梯度、压力梯度和硫化氢质量浓度等影响;井筒中的硫沉积主要受气体携带能力和局部流场扰动的影响。温度、压力下降越大,硫析出越早;在同一流压下,产气量越高,硫析出越早,析出量越大。该研究模拟了气井生产动态,给出了高含硫气井中的硫析出、硫沉积、压力及温度分布规律,计算结果可用于指导现场进行开发方案调整、生产参数优化,为制定硫沉积预防方案提供依据。

Sulfur deposition law in gas wells with high sulfur content

In consideration of the difficulties of sulfur release and deposition prediction in wellbores with high content of sulfur, a mathematical model was built for multi-phase fluid flow and heat transfer in gas wells with high content of sulfur, and a discrimination rule and computing method were given for multi-field coupling sulfur release in wellbore and sulfur deposition. The computing results show that the sulfur solubility from hole bottom to wellhead in gas well with high sulfur content decreases gradually, showing non-linear variation; sulfur release occurs in the wellbore, and the precipitation location and amount are mainly affected by temperature gradient, pressure gradient and H2S mass concentration; and sulfur deposition in wellbore is mainly affected by gas carrying capacity and local flow field disturbance. The greater the temperature and pressure decrease, the earlier the sulfur precipitates; under the same flow pressure, the higher the gas production is, the earlier the sulfur precipitates and the greater the precipitation is. This study simulates the production performance of gas wells and gives the distribution law of sulfur release, sulfur deposition, pressure and temperature in gas wells with high sulfur content; the calculation results may be used to provide guidance for field adjustment of development scheme and optimization of production parameters and provide basis for formulating a scheme to prevent sulfur deposition.