【作者】 李杰训；

【导师】 刘扬；

【作者基本信息】 东北石油大学 ， 油气储运工程， 2011， 博士

【摘要】 三元复合驱是一种重要的三次采油技术,在提高采收率的同时,由于化学剂在驱油过程中的乳化作用和协同作用,造成采出液油水乳化严重,破乳十分困难,需要研究针对三元复合驱采出液的有效破乳方法。大庆油田北一区三元复合驱矿场试验,是国内规模最大的国产化表面活性剂强碱体系三元复合驱大型工业性现场试验。本课题针对北一区三元复合驱采出液乳化严重、油水分离困难的问题,研究了驱油剂对乳状液稳定性的影响规律,驱油剂和固体颗粒对油水分离特性的影响规律,评价研究了化学破乳、重力沉降、离心分离、超声波处理、微波辐射等的破乳效果,优选出了对采出液具有良好破乳效果的破乳剂XJ-1,确定了破乳剂、热化学沉降、离心分离对采出液破乳脱水的适应性,得到了适合不同驱油剂浓度的北一区三元复合驱采出液的最佳破乳参数。本文得出的主要研究结论包括：(1)三元复合驱采出液油水界面上带有过剩的负电荷,Zeta电位随着表面活性剂含量的增高而降低,随着碱含量的增高而升高。三元复合驱采出液的油水动态界面张力随着表面活性剂和碱含量的增高而降低,聚合物对动态界面张力的影响不明显。(2)表面活性剂和聚合物比碱对三元复合驱采出液油水乳化程度的影响显著。在不含碱和聚合物的情况下,随着表面活性剂含量的增高,油珠粒径明显变小,油水乳化程度增大。在表面活性剂低含量情况下,聚合物和碱含量的增加使油水乳化程度增大。(3)石英砂和钙基蒙脱石固体颗粒在油水界面上有吸附,对油珠之间的聚结有显著的阻碍作用,影响了采出液的油水分离特性。(4)适合北一区三元复合驱采出液的破乳剂的RSN值范围是15～19。XJ-1破乳剂对三元复合驱采出液具有良好的破乳效果,在加药量不大于150mg/L的情况下,使三元复合驱采出液经过静置沉降(90min)后的水相油含量和油相水含量降低到2000mg/L左右和5%以下。对于驱油剂含量为低、中、高的三种三元复合驱采出液,破乳剂的最佳加药量分别是50mg/L、75mg/L、150mg/L。(5)在投加适量XJ-1破乳剂的情况下,北一区三元复合驱采出液的最佳游离水脱除温度为40℃,沉降时间为30min,较适宜的热化学脱水温度为65℃。65℃下,经过热化学沉降(24h)的油相水含量可达到0.5%的商品原油含水量控制指标。(6)离心处理对北一区三元复合驱采出液具有显著的油水分离效果,在投加了适量破乳剂XJ-1的情况下,最适宜的离心加速度为984G,离心处理时间为10min,离心处理温度为40℃,经过离心分离后的水相油含量和油相含水量可分别降低到200mg/L和1%以下。(7)机械振荡聚结对北一区三元复合驱采出液的油水分离效果有明显的改善作用,适宜的机械聚结作用时间为0.5min。超声波处理和微波辐射对北一区三元复合驱采出液的油水分离效果没有明显的影响。更多还原

【Abstract】 The alkali-surfactant-polymer (ASP) flooding is an important tertiary oil recovery technology. As a result of chemical agent emulsification and synergy during oil displacement process, the serious oil-water emulsification is evolved followed enhanced recovery ratio. Owing to difficult demulsification, it is necessary to develop effective demulsification method in accordance with ASP flooding produced liquid.The lease test of ASP flooding in N1 Block of Daqing oilfield, is a strong base ASP flooding industry field trial with the largest scale localization of surfactant manufactures in domestic. This paper aims at the extremely difficult oil-water separation of the ASP flooding produced liquid in N1 Block. The influence law of oil displacement agent on emulsion property, oil displacement agent and solid particles on oil-water separation are studied. Based on the evaluation for demulsifying effect of chemistry demulsification, gravity settling, centrifugation, ultrasonic treatment and microwave radiation, XJ-1 demulsifier with fine demulsifying effect on produced liquid is optimized. Then the adaptability of demulsifier, thermal chemical settlement and centrifugation on demulsification is determined. Thus the optimum demulsification parameter suit for different oil displacement agent content of ASP flooding produced liquid in N1 Block is got.The main research conclusions drawn in this paper include:(1) Superfluous negative charge is left on the oil-water interface of ASP flooding produced liquid. Zeta potential decreases with the increase of surfactant content, and increases with the increase of alkali content. The dynamic tension of oil-water interface for ASP produced liquid decreases with the increase of surfactant and alkali content, while polymer affects the dynamic interfacial tension little.(2) Surfactant and polymer affect the emulsification degree of ASP produced liquid more notable than alkali does. Bead size of oil droplets decreases significantly with the increase of surfactant content in the case of no polymer and alkali, and the emulsification degree increases. Emulsification degree increases with the increase of polymer and alkali content at the low content of surfactant.(3) Quartzite and Calcium base montmorillonite particles can be adsorbed on the oil-water interface, so it has remarkable hinder effect for the coalescence of oil droplets and it influences the oil-water separation features of produced liquid.(4) The RSN value range of demulsifier suit for the ASP produced liquid in N1 Block is 15～19. XJ-1 demulsifier has fine demulsifying effect on ASP produced liquid. While dosage less than 150mg/L, the oil content of water phase and water content of oil phase for ASP produced liquid can respectively be reduced to 2000mg/L and 5% during the static settlement of 90 minutes. For three kinds of ASP flooding produced fluid with low, medium and high oil displacement agent content, the optimum demulsifier dosage is respectively 50mg/L,75mg/L and 150mg/L.(5) Under the condition of adding proper XJ-1 demulsifier, the best removal temperature of free water for ASP flooding produced fluid in N1 Block is 40℃, with the settling time 30min, and the suitable thermo-chemical dehydrating temperature is 65℃. The water content of oil phase can achieve to below 0.5%, which is the water content control index of crude oil for external transport, after 24h thermal chemical settlement with 65 "C temperature.(6) Centrifugal processing has significant effect on water-oil separation of ASP produced liquid in N1 Block. Under the condition of adding proper XJ-1 demulsifier, the optimum centrifugal acceleration is 984G, with centrifugal processing time of 10min and centrifugal processing temperature of 40℃. The oil content of water phase and water content of oil phase can respectively be reduced to below 200mg/L and 1% after centrifugal separation.(7) Mechanical oscillation coalescence obviously has improved effect on water-oil separation of ASP produced liquid in N1 Block. The suitable effect time of mechanical coalescence is 0.5min. Ultrasonic wave processing and microwave radiation do not have apparent effect on water-oil separation of ASP produced liquid in N1 Block.更多还原