一种计量稠油中油气水三相流的方法和装置研究

Investigation on the Oil-Water-Gas Measurements in Viscous Oil

油田现场稠油井黏度大、流动性差,传统的分离计量方法很难对其准确计量;另外,稠油油井的流量范围较宽,每天产油量可以从几桶到1 000多桶,可以从不含气到含气率高达80%,一般计量设备难以覆盖这样的井况条件。为了解决这些难题,研究了一种计量稠油中油气水三相流的方法,可以适应较宽的油井产量范围,该方法包含一个文丘里流量计、双能伽马传感器和配备差压传感器的小型分离器。当稠油多相流流量较高处于文丘里流量计的计量范围内时,采用文丘里流量计和双能伽马传感器来测量稠油中的油气水流量,同时考虑低雷诺数流动条件下对文丘里流出系数的实时动态计算,建立了适当的模型。当稠油多相流流量处于文丘里流量计的下限或呈间歇流时,利用小型分离器内累积的液相差压对液相进行称重式计量,结合伽马传感器测得的相分率,可得油气水流量。该方法利用伽马射线技术测量稠油的相分率,使得稠油的相分率计量更精确,不受稠油形态的影响;同时,结合准确的称重计量原理,真正实现了对稠油进行油气水三相的在线实时计量。实验结果表明,液相流量、含水率、气流量标准偏差分别为4.2%、1.5%、6.3%。

Due to the high viscosity and poor mobility,it＇s difficult to measure the viscous oil well accurately with traditional test separator.Besides,viscous oil wells have a wide range of flow rates,often from several to thousand barrels per day,while the GVF varies from 0to 80%.So few measuring devices are able to test viscous wells.To address this issue,this paper proposes a method for oil-water-gas measurements in heavy oil applications,which covers a wide flow range.It includes a Venturi meter,a dual gamma sensor and a mini separator equipped with a differential pressure transmitter（DPT）.When the viscous oil flow rates are in the measuring range of Venturi,aproper-sized Venturi and a dual gamma sensor are used to measure the flow rates of oil,water and gas,respectively.Since the viscous oil is flowing with low Reynolds number,a suitable model was established to calculate the discharge coefficient of the Venturi.When the multiphase flow rate falls outside the low limit of the Venturi meter or it is an intermittent flow,the liquid mass flow rate can be obtained through a mini separator,where the liquid accumulates and generates differential pressure across the separator.Combing with gammasensor,we can get the flow rates of oil,water and gas respectively.In this method,gamma rays technology is used to conduct the phase fraction measurement more accurately.This technology is independent of viscous oil flow patterns such as emulsion.Coupling with the weighing method through the mini separator,a full range on-line measurement of oil,water and gas in viscous oil can be realized.The experiments on a prototype meter（2inch Venturi and DN50piping）made by this method were carried out in a multiphase test loop.The test results indicate that the measurement standard deviations of liquid flow rate,WLR（water to liquid ratio）and gas flow rate are 4.2%,1.5% and 6.3%,respectively.