牙哈凝析气藏岩心改性前后润湿性变化研究

RESEARCH ON WETTABILITY CHANGE BEFORE AND AFTER CORE MODIFICATION IN GAS CONDENSATE RESERVOIRS

经二氧化硅溶胶和FC3721处理前后对比研究玻璃毛细管液柱高度变化、岩石的润湿角改变、岩石的表面元素改变和岩心自发渗吸的渗透率变化。能谱分析结果表明联合处理后岩心表面含有55.82%的氟元素和44.18%的硅元素,FC3721中的含氟烷基已经结合在岩心表面上和多孔介质中。毛细管实验和自发渗吸实验结果表明处理后,岩石表面的润湿性发生改变,在气相/水相体系中,可以将亲水相岩石表面转变为亲气相岩石表面,在油相/气相体系中,可以将亲油相岩石表面转变为弱亲油相或中性润湿岩石表面。

Natural sandstone core wettability changing features from water-wetting or oil-wetting to the gas-wetting after the silica sol and FC3721 treated was studied by using energy spectrum analysis,capillary rise method,spontaneous imbibition and wetting angle determination methods. Energy spectrum analysis results show that,the core surface contains 55. 82% fluorine element and 44. 18% silicon element,which indicate that the fluorine alkyl in FC3721 have been combined in the core surface and porous medium. Capillary and spontaneous imbibition experiments show that after the silica sol and FC3721 treatment,the core water-wetting surface transfer into gas-wetting surface in the water / gas system; strong oil-wetting surface changes into the weak oil-wetting or neutral wetting surface in oil / gas system.