Experimental Studies On The Mechanism And Parameters Optimization Of Ultrasonic Blockage Removal

During the development of offshore oil fields,Pollution and blockage will cause the change of reservoir seepage space and decrease of oil production,so it is necessary to implement blockage removal measures to increase production.Equipment for offshore oil production are expensive.Chemical agents injected by traditional chemical blockage removal methods will corrode the casing and shorten the service life of oil production equipment.Moreover,the offshore oil production platforms are limited,and the storage of chemical agents is also a difficult problem if a large amount of chemical agents are to be injected.Therefore,it can be considered to use ultrasonic blockage removal with simple equipment,small investment and reusability.Firstly,ultrasonic wave was used to treat the experimental oil sample,and the effects of temperature,ultrasonic frequency and ultrasonic treatment time on the effect of viscosity reduction were studied.Then,a self-made sand filling pipe model is used for pollution evaluation,and the pollution evaluation of sand filling models with different initial permeability,different pollution depths and different pollutants is studied.Then,a self-developed simulated wellbore device is used to simulate the formation through artificial sand filling for conventional displacement experiments.Inorganic scale and polymer,two common pollutants in the oil field exploitation process,are used to pollute the simulated formation re SPEctively.Ultrasonic blockage removal technology is used to carry out blockage removal experimental research and study the blockage removal depth of ultrasonic wave.At the same time,through the analysis of the blockage removal effect,the processing time,processing power and other blockage removal parameters of ultrasonic wave are optimized.Finally,the mechanism of ultrasonic blockage removal is analyzed.The results show that: with the increase of the experimental temperature,the viscosity reduction effect of the ultrasonic treatment of the experimental oil samples becomes worse,and when the experimental temperature exceeds 45 ℃,the viscosity reduction rate decreases rapidly.The pollution degree of the sand filling model is affected by factors such as the type of pollutant,the amount of pollutant,and the permeability of the model.The larger the initial permeability of the sand filling model,the more serious the pollution of the model.When the initial permeability of the sand filling model is similar,the pollution of the sand filling model by the polymer is more serious than the inorganic scale.As the pollution depth increases,the degree of pollution increases.In the power range of the experimental study,the greater of the ultrasonic power,the better of the deblocking effect.When the other conditions are the same,the effect of ultrasonic wave to remove the clogging of inorganic scale is better than that of polymer.The effect of ultrasonic deblocking is related to the processing time.Under the experimental conditions,the permeability of the sand filling model increased rapidly during the ultrasonic treatment time of 20-60 min,and then slowed down.Due to the attenuation of ultrasonic waves during propagation,the attenuation is not only related to the parameters of the ultrasonic waves,but also to the nature of the propagation medium and the external conditions such as the temperature and pressure of the propagation medium.Therefore,when applying ultrasonic to remove blockage on site,the construction parameters also need to be screened in combination with the field test effect to obtain the best effect and maximum economic benefit.