水平井筒射孔完井变质量流动压降规律

影响水平井产能和向井入流剖面的因素很多,水平井筒沿程压降是其中一个重要因素。结合水平井筒生产实际,在大庆多相流试验环道基础上,设计了壁面注入系统和变质量流动试验段,针对射孔水平井筒变质量流动规律进行了单相和两相变质量流动试验研究。结果表明,单相水平井筒沿程压降随注入比变化,并且存在临界注入比,当注入比超过临界注入比时,压降随着注入比增加显著。进一步的数值模拟研究揭示了其中的原因:当超过临界注入比后,射孔孔眼下游出现流动分离,混合压降开始起作用,从而引起压降的显著增加。油水两相变质量流动除了受注入比影响外,还受到含水率变化的影响,在高流量条件下,40%含水率时压降最高,流型为分散流型;低流量下,压降随含水率变化不大,流型为分层流型。该研究结果对完井设计有一定指导意义。

Pressure drop of variable mass flow in perforation completion of horizontal wellbore

There are many factors that affect the productivity of horizontal wells and the inflow profile of directional wells, one of which is the pressure drop along the path of horizontal wellbore. Based on the practice of horizontal wellbore production and Daqing multiphase flow test loop, a test section of wall injection system and variable mass flow is designed. Single-phase and two-phase variable flow experiments are conducted to research the variable mass flowing rule of perforated horizontal wells. Research results show that the pressure drop along the path of the single-phase horizontal wellbore changes with the injection ratio and there is a critical injection ratio. When the injection ratio surpasses the critical injection ratio, pressure drop increases dramatically. The cause is illustrated with further numerical simulation research. When the injection ratio exceeds the critical injection ratio, flow separation occurs nearby the perforation, as well as the mixing pressure drop works. As a result, the pressure drop rises dramatically. Besides the injection ratio, the two-phase oil/water variable flow is influenced by the change of water percentage. Under high flow conditions, the pressure drop is the highest when the water percentage is 40%, as well as the flow pattern is dispersed. Under low flow conditions, the pressure drop changes little with the water percentage, as well as the flow pattern is stratified. The research result may be a good reference to well completion design.