高含二氧化碳采出物节流特性的实验研究

Experimental Study on Characteristics of Produced Crude with High CO_2 Content Passing Throttle Valve

随着CO_2驱油技术的发展,高含CO_2采出物在通过井口节流阀时由于焦耳-汤姆逊效应会造成阀后低温,继而可能产生冻堵的风险。本文通过实验研究了高含CO_2采出物(CO_2/天然气/N2/油/水)在通过节流阀时的温降情况,分别分析了阀前后压降、气液比、含水率等对节流温降的影响。研究发现:节流阀前后压降与节流温降呈线性关系;节流压降越大、二氧化碳的含量越高、气液比越大、含水率越低,节流效应越明显,阀后温度也越低,藉此提出基于阀后温度确定井口防冻的临界气液比的方法,该研究为高含CO_2油井井口防冻及集输工艺提供技术指导。

With the development of CO2 enhanced oil recovery technology,when the high CO2 content crude produced from well pass the wellhead throttle valve,there is a temperature drop phenomenon after throttle valve because of the Joule-Thomson effect,and then freezing and blocking maybe occur.The temperature drop phenomenon of the high CO2 content crude（CO2/nature gas/N_2/oil/water） was investigated by experiments when it pass the throttle valve,the influence of the pressure drop between the valve front and back,gas-liquid ratio and water cut etc was analyzed respectivedy on the throttling temperature drop.It showed that a linear relationship between pressure drop and temperature drop between the valve front and back was found.It also showed that throttling effect more obviously and temperature after throttle valve was lower with the throttling pressure drop greater,the content of CO2 higher,gas-liquid ratio larger.The study provided technical guidance on wellhead freeze of the high CO2 content well and gathering and transportation technology.