SYSTEM AND METHOD FOR ULTRASONICALLY TREATING LIQUIDS IN WELLS AND CORRESPONDING USE OF SAID SYSTEM |
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申请号 | EP11701850.7 | 申请日 | 2011-02-07 | 公开(公告)号 | EP2534332B1 | 公开(公告)日 | 2016-09-28 |
申请人 | Rexonic Ultrasonics AG; | 发明人 | SOLENTHALER, Peter; | ||||
摘要 | |||||||
权利要求 | |||||||
说明书全文 | The invention relates to the use of an ultrasonic transducer, to a system for treating liquids in wells and to a method for treating liquids in such wells according to the preamble of the independent patent claims. It is known to treat liquids in wells such as gas, oil or water wells with ultrasonic energy in order to reduce the viscosity of the liquid without the use of chemical reagents or steam generators. Such use of ultrasonic energy e.g. has been disclosed in All these known solutions, however, have certain drawbacks. In particular, there are problems in context with transmission of ultrasonic energy to bore wells over relatively high distances which typically may be greater than several kilometres. Also, known devices have a poor efficiency. It is therefore an object of the present invention to overcome the drawbacks of the prior art, in particular to provide a system and a method for treating liquids in gas, oil or water wells which can be used also in deep wells and which has a high efficiency for treating the liquid, in particular for reducing its viscosity. According to the invention, these and other objects are solved with the use of an ultrasonic transducer, a system and a method for treating liquids according to the independent patent claims. It has been found that the use of an ultrasonic transducer with a resonator connected thereto where at least one end of the resonator is connected to a front surface of the transducer at the point of longitudinal oscillation maximum and where the length of the resonator is tuned to an integral multiple of a half acoustic length of the longitudinal oscillation of the transducer is particularly efficient for treatment of liquids in wells such as gas, oil or water wells. Such resonators are known per se in the art e.g. as shown in According to a preferred embodiment the resonator is tubular or a solid round rod. It is, however, also conceivable to have non tubular resonators such as resonators with a polygonal cross section or - depending on the shape and size of the well to be treated - resonators with an overall conical shape or resonators with a wave like outer shape. However, care should be taken that the resonator is properly tuned to the resonance frequency of the transducer. In particular, an ultrasonic transducer with a resonator is used, where the transducer is additionally provided with a means for adapting the power to the impedance, in particular an impedance matching transformer for up converting the voltage of an incoming ultrasonic signal. In case of transmission of ultrasonic energy over relatively large distances, e.g. over cables having a length of more than 3km, high losses will occur in the cable. With this matching transformer the energy supplied to the transducer is maximum by adaptation to the impedance of the cable and the device formed by the transducer with the resonator. Accordingly a further aspect of the invention is directed to a system for treating liquids in gas, oil or water wells. The system comprises an ultrasonic treatment device. The ultrasonic treatment device has a transducer with a resonator connected thereto. At least one end of the resonator is connected to a front surface of the transducer at the point of longitudinal oscillation maximum. The length of the resonator is tuned to an integral multiple of half an acoustic length of the longitudinal oscillation fed from the transducer to the resonator. According to the invention, the system comprises a generator for generating ultrasonic power. The signal are generated at a -relatively high voltage. The system further comprises a long cable for connecting the generator to the treatment device. The device further comprises means for adapting the generator to the impedance of the cable, the transducer and the resonator, in particular a matching network transformer to transfer a maximum of generator power to the transducer in the well. In a preferred embodiment the resonator is tubular. Other shapes are possible depending on the use. According to a further preferred embodiment the transformer or the matching impedance network adapting means is directly attached to the tubular resonator. Therewith, one integral device can be formed which easily can be placed in a well, e.g. by attaching it to a mechanical cable. The matching transformer is integrated in the device so that there is no need for additional connectors or cables which could be damaged during use. Typically the cable has a length of more than 3km, preferably around 6 to 8km. Preferably, an ultrasonic frequency of 5 to 25kHz with a voltage of upto 2kV will lead to the transducer in the well. According to a further preferred embodiment of the invention, there is provided a set of different resonators having different shapes which can be chosen depending from the geometry of the well or depending from the composition of the liquid to be treated. Typically, the set comprises at least two resonators having a different shape, preferably around eight different sizes and/or shapes. The invention will now be explained in more detail with reference to the drawings which show:
The treatment device 1 is shown in more detail in The transformer 10 is arranged in a metal casing which is attached to the resonator 2 through mechanical connections such as welds or screws. In operation, the resonator 2 is generating ultrasonic waves which are radially distributed around the resonator. Because of cavitation in the fluid, the viscosity of the fluid, in particular of oil is reduced. Depending on the specific circumstances, other resonators may be used. In particular, the resonator may be formed of a rod (not hollow) or may have a rectangular or other polygonal cross section. Also, it is possible to use two transducers arranged on both sides (seen in the axial direction) of the resonator in order to have a "push-pull" operation. As schematically shown in |