基于CFD的井下油水两相文丘里流量计优选

Optimization of the CFD-based Downhole Oli-water Two-phase Venturimeter

为解决因流量、油水比变化及两相流态的复杂性所带来的井下文丘里管油水两相测量精度和设计选型等问题,根据多相流理论及计算方法,在不同入口流量、不同油水比条件下,模拟计算3种不同文丘里流量计的油水两相流场并进行方案优选。计算结果表明,介质接近油相或水相时,两相流态分别接近层流或湍流。流体经文丘里喉部后,油水两相分层特征显著。根据多相流计量精度的需要,通过CFD计算对比,优选出小流量下压降随液体粘度有显著变化的文丘里管设计方案。

The flowrate condition, change of oil-water ratio and complexity of two-phase flow pattern affect the oil-water two-phase measurement precision and model selection of design concerning the downhole venturime- ter. Considering the problem, a simulation calculation of the oil-water two-phase flow field of three different ventu- rimeters was conducted and the scheme was optimized in different entrance flowrate and different oil-water ratio con- ditions according to the multiphase flow theory. The calculation shows that when the medium is close to oil phase or water phase, the two-phase flow pattern is close to laminar flow or turbulent flow. The characteristic of oil-water two-phase stratification is remarkable when the fluid goes through the venturi throat. According to the requirement of multiphase flow calculation precision and through CFD-based calculation comparison, the design scheme of venturi tube was optimized under small flow with pressure drop changing remarkably with liquid viscosity.