特高温低渗透油藏乳液表面活性剂驱现场试验

摘要

针对胜利油田Ⅴ类化学驱原油温度高、渗透率低的问题,运用乳液表面活性剂促使油水两相产生乳化现象,增加驱替相黏度,有效驱替分布在油藏边缘及角隅部位的残余油,扩大波及体积;同时利用低张力表面活性剂将油水界面张力降至10-3mN/m的超低水平,降低黏附性,提高洗油效率,两者组合得到乳液表面活性剂驱油体系.将该驱油体系应用于纯17-1区块,经过20多个月驱油体系的不断注入,截至2017年7月,对应油井日产油量由1.3 t/d上升至6.3 t/d,综合含水由83.0％下降至74.1％,有效改善层间吸水差异状况,取得了较好的效果.该研究成果对胜利油田Ⅴ类化学驱油藏开发具有重要意义.%Class Ⅴ reservoirs in the Shengli Oilfield with chemical flooding are characterized by high crude oil temperatures and low permeability.By using emulsion surfactant,emulsion of oiL/water can be promoted to enhance viscosity of displacing facies,to drive residual oil on edges or in corners of reservoirs and to expand swept volume;At the same time,surfactants with low tension can be used to reduce tension on oil/water contact to ultra-low levels around 10-3 mN/m to minimize viscosity and to maximize flushing efficiencies.The emulsion surfactant oil-displacing system can be generated through combination of the two.The oil-displacing system has been deployed in the Chun-17-1 Block.With continuous application of the oil-displacing system in the past 20 some months,oil productivities increased from 1.3 t/d to 6.3 t/d and with total water cut reduced from 83.0％ to 74.1％ up to July of 2017.With differences in water-absorption capacities minimized,satisfactory performances have been achieved.Relevant research conclusions may provide valuable references for development of Class Ⅴ reservoirs in the Shengli Oilfield through chemical flooding.