油井酸化返排液的导电性能及其影响因素分析

Analysis of the Conductivity and Influencing Factors of Oil Well Acidification Back-flow Liquid

油井酸化所产生的酸性返排液进入电脱水器后常引起装置跳闸,严重影响设备安全运行。以渤海某油田油井酸化返排液为研究对象,通过测试可加电压研究了其导电能力,发现返排液中原油乳化层的存在及其强导电特性是导致电脱水器过流的主要原因。通过实验考察了温度、pH值以及酸化渣泥含量等因素对返排液中原油乳化层导电能力的影响。结果表明,升高温度能够明显降低原油乳化层的稳定性和导电能力;在中性pH值范围内油水界面张力值较高,原油乳化层稳定性较差,易发生破乳并使其导电能力降低;酸化渣泥能够增强乳化原油的稳定性及导电能力;将pH值调节至6～8,在添加适当破乳剂的同时升温至80℃对酸化返排液进行预处理,能够有效降低其导电能力。

The acid-containing back-flow liquid produced by acidized oil wells often causes a trip of the electric dehydrator,which has a great influence on equipment.Taking the oil well acidification back-flow liquid in an oilfield of the Bohai Sea as the study subject,its conductivity is investigated by measuring the addictive voltage value.It is found that the presence of crude oil emulsion layer and the high conductive capacity of the liquid are the main causes of the electric dehydrator trip.Through ex-periments,the effects of temperature,pH value and the content of the acidizing sludge on the conductivity ability of the crude oil emulsion layer in the liquid are studied.The results indicate that as the temperature increases,the stability and conductivity of the emulsion layer decrease obviously.In neutral pH ranges,the interfacial tension between the oil-water phase is higher while the crude oil emulsion layer is of low stability,which is beneficial for demulsification and reducing the conductivity.The stabilization and the conductivity of the emulsified crude oil would be enhanced by the existence of acidizing sludge.The pretreatment processes including heating the liquid to 80℃,adding appropriate demulsifi-ers as well as adjusting the pH values to between 6 and 8 can reduce the conductive capacity of acidifica-tion back-flow liquid effectively.