表面活性剂驱油性能评价及其在低渗透油田的应用

Evaluation and Application of a New Surfactant Oil-Displacing Agent in Low Permeability Oilfield

结合低渗透油田储层和化学驱油技术特点,考察了双子型表面活性剂驱油剂YC-2表界面活性、乳化能力及驱油效果。实验结果表明,该驱油剂在浓度为3000 mg/L时的表面张力可以达到30 mN/m左右,与原油间的界面张力可以达到10-3mN/m超低数量级,并且对NaCl和CaCl2体现出较强的抗盐能力;表面活性剂YC-2溶液/原油乳液体系析水快,有利于产出液的破乳。驱油实验结果表明,浓度为3000 mg/L的表面活性剂YC-2溶液在气测渗透率为0.3541×10-3μm2岩心水驱(采收率50%)基础上可进一步提高采收率15%以上;该表面活性剂适用于低渗透油层驱油,随着岩心渗透率的提高,表面活性剂驱油效率降低。该驱油剂产品已在延长油田青化砭、瓦窑堡、青平川等采油厂应用,取得了显著的驱油效果。

Based on the chemical-displacing technology in low-permeability oilfield,the surface/interfacial activity,emulsifing ability and displacing efficiency of a gemini surfactant oil-displacing agent YC-2 were investigated. The results showed that when the concentration of YC-2 was of 3000 mg/L,the surface tension of YC-2 solution was around 30 mN/m,and the interface tension between YC-2 solution and the crude oil could reached the ultra-low order magnitude(率 10-3mN/m). The YC-2 solution had strong salt resistance to NaCl and CaCl2. Moreover,the YC-2 solution/crude oil emulsion exudated water quickly,which was favorable for the disemulsion of the produced fluid. The oil displacement experiment showed that oil-displacing agent YC-2 solution with the concentration of 3000 mg/L could enhance the oil displacement efficiency of the core of Kg0.3541×10-3μm2over 15% based on the water flooding(50%). With the increase of the permeabililty of the core,the displacing efficiency of the YC-2 solution reduced,indicating that the YC-2 was suitable for the low permeability reservoir. The surfactant YC-2 had been applied in Qinghuabian,Wayaobao,Qingpinchuan oilfield factory of Yanchang Oilfield,and remarkable displacement efficiency had been obtained.