润湿性对油水渗流特性的影响

EFFECTS OF WETTABILITY ON OIL-WATER FLOW CHARACTERISTICS

为了研究润湿性对不同渗透率岩心中油水渗流及水驱油效果的影响，利用低、中、高三种不同渗透率的人造露头砂岩心，通过甲基硅油、模拟油等化学剂将其润湿性由亲水改为中性和亲油性，研究了不同渗透率岩心，当润湿性改变为亲油和中性润湿条件后油水渗流特性的变化，岩心润湿性的反转程度通过动态接触角法来确定。实验结果表明，将岩心的润湿性由亲水和亲油状态转向中性润湿条件，均有利于增加油的流动能力，同时增加水的流动阻力，从而降低流度比，改善水驱效果。低渗油藏孔隙表面的亲油性润湿条件是注水压力高的原因之一，建议将其润湿性转为中性润湿条件以提高水的注入能力。

To determine the effects of wettability on oil-water flow and water displacement efficiency in cores with different permeabilities, artificial outcrop cores with low, medium and high permeabilities have been selected to perform the analysis where chemical solutions such as methyl silicone oil and simulated oil have been adopted to convert the wettability from water wet into neutral and oil wet. Through the analysis, the variations of oil-water flow characteristics in cores with different permeabilities when the wettability changes into oil wet and neutral have been investigated and the reversal degree of wettability can be determined by dynamic contact angle method. Results of the experiment show that the wettabilities convert from oil wet or water wet into neutral results in the enhancement of oil mobility and increment of water flow resistance, thereby, the mobility ratio can be reduced and water displacement efficiency can be promoted. Since the oil-wet pore surface in low-permeability oil reservoirs is one of the reasons that cause high water injection pressure, it is advisable to change the wettability into neutral in order to strengthen the injection capacity.