Khan Nasir, Pu Chunsheng, Li Xu, He Yanlong, Zhang Lei, Jing Cheng
School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China.
School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China.
Ultrason Sonochem. 2017 Sep;38:381-389. doi: 10.1016/j.ultsonch.2017.03.034. Epub 2017 Mar 18.
It is imperative to recover the well productivity lose due to formation damage nearby wellbore during variant well operations. Some indispensable issues in conventional techniques make ultrasonic technology more attractive due to simple, reliable, favorable, cost-effective, and environment friendly nature. This study proposes the independent and combined use of ultrasonic waves and chemical agents for the treatment of already damaged core samples caused by exposure to distilled water. Results elucidate that ultrasonic waves with optimum (20kHz, 1000W) instead of maximum frequency and power worked well in the recovery owing to peristaltic transport caused by matching of natural frequency with acoustic waves frequency. In addition, hundred minutes was investigated as optimum irradiation time which provided ample time span to detach fine loosely suspended particles. However, further irradiation adversely affected the damaged permeability recovery. Moreover, permeability improvement attributes to cavitation due to ultrasonic waves propagation through fluid contained in porous medium and thermal energy generated by three different ways. Eventually, experimental outcomes indicated that maximum (25.3%) damaged permeability recovery was witnessed by applying ultrasonic waves with transducer #2 (20kHz and 1000W) and optimum irradiation timeframe (100min). This recovery was further increased to 45.8% by applying chemical agent and optimum ultrasonic waves simultaneously.
在各种油井作业过程中，恢复因井筒附近地层损害而损失的油井产能至关重要。传统技术中存在一些不可避免的问题，使得超声波技术因其简单、可靠、良好、经济高效且环保的特性而更具吸引力。本研究提出单独及联合使用超声波和化学剂来处理因暴露于蒸馏水中而受损的岩心样品。结果表明，具有最佳参数（20kHz，1000W）而非最大频率和功率的超声波，由于其固有频率与声波频率匹配所引起的蠕动传输，在产能恢复方面效果良好。此外，研究发现100分钟为最佳辐照时间，该时间跨度足以分离细小的松散悬浮颗粒。然而，进一步辐照会对受损渗透率的恢复产生不利影响。而且，渗透率的提高归因于超声波在多孔介质所含流体中传播时产生的空化作用以及通过三种不同方式产生的热能。最终，实验结果表明，使用换能器#2（20kHz和1000W）的超声波并在最佳辐照时间范围（100分钟）内，受损渗透率的最大恢复率为（25.3%）。通过同时应用化学剂和最佳参数的超声波，这一恢复率进一步提高到了45.8%。
