摘要
夏季压裂施工中,由于胍胶压裂液受到细菌等微生物滋生的影响,可能导致液体腐化变质,致使压裂液失效.为此通常需要加入杀菌剂对压裂液中腐生菌进行消除,但目前缺少能够在微观层面评价杀菌剂杀菌效果的技术手段.为此,提出了一种基于光纤光镊的杀菌剂杀菌效果评估技术手段,利用锥形光纤光镊捕获添加杀菌剂前后的腐生菌,在微观尺度分析其运动规律,以此反演杀菌剂的杀菌效果.实验结果表明,该方法可以有效评估腐生菌的活性,对于添加杀菌剂后,腐生菌细胞失活,其运动幅度大幅下降,大约只在 0.8~0.9 μm.而对于正常的腐生菌,其运动幅度通常在 12.1 μm左右.证实了该方法在评估杀菌剂杀菌效果的可行性,为直接评价杀菌剂性能的优劣提供了可靠的理论依据.
Abstract
In summer fracturing operation,microorganisms such as bacteria can cause the guar gum fracturing fluids to spoil and lose their effectiveness.Bactericides have thus to be used in the fracturing fluids to kill the bacteria.Presently there is no technical means of evaluating the performance of the bactericides.In this study a method based on optical fiber tweezer(OFT)is presented to evaluate the performance of the bactericides.The saprophytic bacteria are first captured before and after adding a bactericide into a fracturing fluid with a conical OFT,the movement pattern of the bacteria is then analyzed at microscopic scale,and this process can be used to invert the effect of the bactericides.Experimental results show that this method can be used to effectively evaluate the activity of the saprophytic bacteria.After adding bactericides into a fracturing fluid,the cells of the saprophytic bacteria become inactive and the movement distance of the saprophytic bacteria is greatly reduced to about only 0.8-0.9 μm.For saprophytic bacteria without contacting with bactericides,the movement distance is generally about 12.1 μm.The study proves that the OFT method is effective in evaluating the performance of bactericides,and it provides a reliable theoretical base for the direct evaluation of the performance of bactericides.