天然气对渤海某油田原油脱水效果的影响

Effect of Natural Gas on Oil Dehydration of Bohai Oilfield

为分析天然气对原油脱水效果的影响机理,通过原油天然气混合装置,向渤海某油田现场已加注水溶性破乳剂的1级分离器入口、2级分离器入口、电脱水器入口原油通入天然气,研究了气体流量、通气时间对乳化原油中水滴粒径的影响,考察了气体流量对原油脱水量的影响,并在油田现场开展在用有机硅消泡剂的加注试验,分析了消泡剂对原油脱水效果影响的原因。结果表明,随天然气流量增加,1级分离器入口乳化原油水滴粒径和静态脱水速度的变化较小;2级分离器入口及电脱水器入口乳化原油水滴粒径增加、静态脱水速度加快,当天然气流量为3 L/min时,乳化原油水滴粒径平衡值减小、静态脱水速度降低。在2级分离器入口及电脱水器入口加注消泡剂,脱水与脱气效果随着消泡剂加注浓度的升高而改善。消泡剂促进了天然气在原油中的析出,气泡的上浮加剧了原油中乳化水滴的运动,增大了小的乳化水滴互相碰撞聚并为大水滴的概率,使原油脱水效果得到改善。

In order to analyze the influence mechanism of natural gas on oil dehydration,the natural gas was injected into the inlet oil of the first stage separator,the second stage separator and the electronic dehydrator which already had water base demulsifier in Bohai oilfield through gas-oil mixture equipment.The effect of gas dosage and time on the diameter of waterdrop in roily oil was studied,the effect of gas flow rate on oil dehydration was studied,the field trial of organic silicon defoamer was carried out and the influence of defoamer on oil dehydration was analyzed.The results showed that the waterdrop diameter and the dehydration rate of roily oil in the inlet of the first stage separator changed slightly as increasing flow rate of natural gas.While the waterdrop diameter increased and the dehydration rate accelerated in the inlet of the second stage separator and electronic dehydrator.When the flow rate of natural gas was 3 L/min,the balanced diameter of waterdrop reduced and the dehydration rate decreased.After the defoamer was injected into the inlet of the second stage separator and electronic dehydrator,the dehydration and degassing effects improved with increasing concentration of defoamer.The defoamer accelerated the degas rate of natural gas in the oil.The emulsifying waterdrop motion was accelerated when the gas bubble floated upward,which increased the coalescence rate of the small emulsifying waterdrop into the big one and finally improved the dehydration of oil.