苏里格气田典型区块采出水乳化特征及乳化影响因素分析

Emulsification Characteristics and Influencing Factors of Produced Liquid in Typical Blocks of Sulige Gas Field

苏里格上古气藏普遍含有凝析油,部分集气站的凝析油采出液乳化严重,对集气站的正常生产影响较大。以苏里格气田凝析油采出液为研究对象,开展典型区块采出液乳化特征分析及乳化影响因素研究。结果表明,5个站点采出水凝析油乳状液的组成差异较大,乳状液的稳定与Zeta电位和矿化度呈现良好的对应关系,Zeta电位的绝对值越大,乳状液越稳定,水相矿化度越高,乳状液的稳定性越低。5个采出水乳状液中醇类质量分数为1.48%~4.80%,酯类质量分数为2.08%~6.34%,醇类和酯类极性有机物会在界面上与亲水性的表面活性剂形成复合界面膜,有利于形成凝析油乳状液。苏里格气田乳状液总体上是以水相为连续相、油为分散相(O/W);对于部分油滴,油为连续相,水为分散相(W/O),最终形成复杂的水包油包水(W/O/W)型。随着泡排剂、固体悬浮物用量的增加,凝析油模拟乳状液体积分数均呈现先增大后减小的趋势。当泡排剂质量分数为0.6%、悬浮物质量分数在0.4%时,凝析油模拟乳状液体积分数最大,而缓蚀剂浓度对凝析油模拟乳状液形成体积无明显影响。

Gas condensate exists generally in the upper Paleozoic Sulige gas reservoir.During production,it was found that the produced liquid of condensate in some gas gathering stations was seriously emulsified,which had a great impact on the normal production.Taking the produced liquid emulsion of condensate in Sulige gas field as the research object,the emulsification characteristics and influencing factors of produced liquid in typical blocks were analyzed.The composition of the five produced condensate emulsions was quite different,and the stability of the emulsions was in good correspondence with zeta potential and salinity.The greater the absolute value of Zeta potential,the more stable the emulsion.The higher the salinity of the aqueous phase,the lower the stability of the emulsion.The mass fraction of alcohols and esters in five produced condensate emulsions was 1.48%—4.80%and 2.08%—6.34%,respectively.the polar organic substances of alcohols and esters would form a composite interface facial film with hydrophilic surfactant at the interface,which was conducive to the formation of condensate emulsion.In the condensate emulsion in Sulige gas field,the water phase was continuous phase and oil was dispersed phase.For some single oil droplet,oil was a continuous phase and water was a dispersed phase,which finally formed a complex water-in-oil-in-water(W/O/W)type emulsion.With the increase of foaming agent and suspended matter content,the volume fraction of the simulated condensate emulsion increased first and then decreased.When the mass fraction of foaming agent was 0.6%and the mass fraction of suspended solids was 0.4%,the volume fraction of the simulated condensate emulsion was the largest,while the concentration of corrosion inhibitor had no obvious effect on the volume fraction of condensate emulsion.