油井采出液预分水用轴向水力旋流器的实验研究

高含水油井采出液的高效预分水是目前油气集输处理领域面临的关键难题之一，轴向水力旋流器因具有结构紧凑、分离效率高等优点而得到了国内外的广泛关注。本文针对自主研发的油井采出液预分水用轴向水力旋流器开展了室内实验研究。与切向水力旋流器对比，轴向水力旋流器不仅分离效率更高，而且油出口处的油滴聚结长大近1.8倍，在分水率高于50%的情况下，水出口处的含油浓度低于1000mg/L；轴向水力旋流器压降较低，且压降比与分流比呈线性相关。分流比、含水率和流量对分离性能均有显著影响，其中分流比的变化直接影响油核的大小和稳定性，室内样机的最佳分流比为0.45，当含水率为90%、处理量为1.00m³/h时分水率与含油浓度分别为62.9%和432.8mg/L；含水率高于75%时分离性能良好；室内样机的最佳流量为1.50m³/h。自主研发的轴向水力旋流器不仅满足性能要求，而且在操作弹性、可控性方面较切向水力旋流器均有一定的提升。

Experimental study of axial hydrocyclone for pre-dehydration from wellstream

Efficient pre-dehydration from high water cut wellstream is one of the key problems in the field of oil and gas gathering and transportation at present. Axial hydrocyclone has attracted wide attention at home and abroad because of its compact structure and high separation efficiency. The laboratory experiments were carried out on the axial hydrocyclone for pre-dehydration from wellstream developed by ourselves. Compared with the tangential hydrocyclone, the axial hydrocyclone not only exhibits higher separation efficiency, but also promotes the oil droplets at the oil outlet grow nearly 1.8 times, and the oil concentration at the water outlet is lower than 1000mg/L when the dehydration rate is higher than 50%. The pressure drop of axial hydrocyclone is lower, and the pressure drop ratio is linearly related to the split ratio. The split ratio, water cut and flow rate have significant effects on the separation performance of the axial hydrocyclone. The change of split ratio directly affects the size and stability of the oil core, and the optimum split ratio is 0.45. When the water cut is 90% and the flow rate is 1.00m³/h, the dehydration rate and oil concentration are 62.9% and 295.4mg/L, respectively. The separation performance is good when the water cut is higher than 75%. The optimum flow rate of axial hydrocyclone is 1.50m³/h. The self-developed axial hydrocyclone not only meets the performance requirements, but also has certain improvement in operational flexibility and controllability compared to tangential hydrocyclone.