Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B28/00—Vibration generating arrangements for boreholes or wells, e.g. for stimulating production
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
  • E21B43/003—Vibrating earth formations
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
  • E21B43/25—Methods for stimulating production

Definitions

• the invention relates to the oil production industry and is intended for the processing of production zones of oil, gas and water wells in order to increase their production rate.
• the working agent used for treating a reservoir is not a substance (chemical reagents, vapour, gas) but physical fields of various kinds, one of which is acoustic waves.
• Patent RU 2196217 There is a known downhole acoustic emitter disclosed in Patent RU 2196217, comprising a supporting housing consisting of an open lower part in contact with the downhole liquid via apertures formed in the open part of the supporting housing, and a sealed part filled with electrically insulating liquid and having an air cavity which is at atmospheric pressure.
• a rod-shaped magnetostrictive transducer In the supporting housing there is placed a rod-shaped magnetostrictive transducer, the upper radiating surface of which interacts with the air cavity.
• an acoustic waveguide made in the form of a metal cylinder rigidly and coaxially connected by its upper end surface to the lower radiating surface of the transducer by a soldered joint.
• the acoustic waveguide is connected in a rigid and sealed way along its perimeter in its middle part, coinciding with the zero point of its oscillation, to the supporting housing by means of a circular welded joint, dividing it into an open and a sealed part.
• the lower end surface of the waveguide is placed in the open part of the supporting housing.
• Patent RU 2834789 consisting of a supporting housing with a cavity and apertures in which are positioned a rod-shaped magnetostrictive transducer with an electrical winding on rods and an acoustic waveguide, the upper end surface of which is coaxially connected to the lower radiating surface of the magnetostrictive transducer by means of a soldered joint, while the middle part of the acoustic waveguide, coinciding with the zero point of its oscillation, is connected in a sealed way along its perimeter to the supporting housing, and the upper end of the magnetostrictive transducer is positioned in the air cavity, characterized in that the acoustic waveguide is equipped with a radiating element, and the acoustic waveguide is made in the form of a cylinder passing into a diminishing cone, the cylindrical part of the acoustic waveguide being positioned in the supporting housing, while the conical part is outside the housing, and the upper end of the radiat
• the drawback of this emitter is that the magnetostrictor and winding are always subjected to the corrosive action of the downhole liquid and other fractions, which significantly reduces the service life of the instrument itself.
• the device most similar to the claimed technical solution, accepted as the prototype, is a device for the acoustic treatment of the well bottom zones of productive layers known from Patent RU 2026970, comprising a surface unit consisting of a control unit and art indicator unit connected by cable to the downhole instrument, which is made in three sections and consists of a generator, an acoustic emitter and a sensor, the acoustic emitter being placed in the tower section, the generator being placed in the middle section, and a coupling locator and a sensor being placed in the upper section, the tower section of the downhole instrument being filled with transformer oil and evacuated, the middle section being filled with transformer oil to not more than 3/4 of its volume and being at atmospheric pressure, and the upper section
• a drawback and deficiency of said device is the presence in the emitter design of a pressure compensator made in the form of a bellows, which reduces the operating reliability of the device owing to the powerful action of the acoustic field on the bellows, which may damage the fastening of the bellows and cause it to fail, especially in view of the downhole conditions in which it operates, while a second drawback is the thermal limitations of the operation of the electronic units of the generator and the signal transducer.
• the aim of the proposed invention is to eliminate the contact between the current- carrying parts of the magnetostrictive transducer and the corrosive downhole medium, and in general to enable the device to operate effectively over a wide range of temperatures and pressures.
• the technical result is an increase in the operating reliability of the emitter.
• the acoustic emitter comprises a housing in which are positioned a chamber communicating with the downhole medium and a sealed evacuated chamber filled with an electrically insulating liquid and containing magnetostrictive transducers with windings connected in series, the electrical connection of which to the geophysical head is provided by means of geophysical cables, the magnetostrictive transducers being secured by holding damps which provide mobility, and which are fastened to the housing through a common bar, the sealed evacuated chamber being equipped with a pressure compensator in the form of a piston mechanism and a special cavity formed so as to allow geophysical sensors to be placed therein
• a characteristic of the device is that the elastic energy of the oscillations of the magnetostrictive transducers through the electrically insulating liquid is transmitted to the housing, and from there into the well space in which the interaction of the pressure waves and the formation of the total acoustic field in the well and in the well bottom zone takes place.
• Fig. 1 shows the emitter in cross section.
• Fig. 2 shows a diagram of the arrangement of two magnetostrictive transducers, showing the oscillations of the medium between their ends.
• the acoustic emitter comprises a housing 1 in which are positioned a chamber 2 communicating with the downhole medium and a sealed evacuated chamber 3 filled with an electrically insulating liquid and containing magnetostrictive transducers 9 with windings connected in series.
• the electrical connection of the transducers 9 to the geophysical head 11 is provided by means of geophysical cables 6.
• the housing of the chamber 2, communicating with the downhole medium through an aperture 4, takes the form of a cylinder 8 ending in a conical part.
• Pressure compensation in the sealed evacuated chamber 3 takes place through a piston mechanism 5, the lower part of which extends into the chamber 2, which communicates with the downhole medium and is at the well pressure, white the other part of the piston mechanism 5 communicates with the sealed evacuated chamber 3.
• the elastic movements of the piston mechanism 5 enable the operability of the emitter to be maintained during a change in the pressure and temperature in the near wellbore space, thereby significantly increasing the reliability of the instrument.
• the magnetostrictive transducers 9 are secured with holding clamps 10 which allow their mobility and are fastened to the housing 1 through a common bar (not shown in the figure), the sealed evacuated chamber 3 being equipped with a pressure compensator in the form of a piston mechanism 5 and being made so that
• geophysical sensors including a coupling locator (not shown in the figure) may be accommodated in special cavities 7 if required.
• geophysical cables 8 which supply the magnetostrictive transducers 9.
• a geophysical head 11 is fited in the housing 1.
• the elastic energy of the oscillations of the magnetostrictive transducers 9 through the electrically insulating liquid present in the sealed evacuated chamber 3 is transmitted to the housing 1 , and from there into the well space in which the interaction of the pressure waves and the formation of the total acoustic field in the well and in the well bottom zone takes place.
• housings 1 with sealed evacuated chambers 3 of different lengths acoustic emitters with different power ratings can be produced.
• the diameter of the emitter with the geophysical head 11 for connection to a standard geophysical cable must be such that it can be used in oil well tubing, with an overall length of about one and a half metres or more.
• the proposed acoustic emitter design does not allow direct contact between the magnetostrictive transducers 9 and the corrosive downhole medium, and this increases service life several-fold.
• the design of the housing 1 of the acoustic emitter allows different sizes of magnetostrictive transducers 9 to be used. This is achieved because it is possible to change the dimensions of the cavities 7 of the seated evacuated chamber 3, in which geophysical sensors may be placed if required, and if such sensors are not present it is possible to eliminate these cavities 7 completely and lengthen the cavities in which the magnetostrictive transducers 9 are arranged, and consequently to change the dimensions of these.
• the invention increases the operating reliability of a downhole emitter by preventing the corrosive destruction of the internal parts of the emitter, increases radiation efficiency as a result of the stable operation of the emitters and the absence of sudden differences in the rate of operation during long-term use,
• the equipment operates in the following manner.
• the ultrasonic emitter is lowered into the drilling zone of a productive layer on a load- carrying geophysical cable through which an alternating voltage at an operating frequency corresponding to the resonance frequency of the magnetostrictive transducer 9 is supplied along the cable from a generator located on the surface.
• a DC magnetic biasing current of about 5-8 A is supplied from the same generator to the same electrical winding, Magnetostrictive transducers 9, connected in series, transfer the elastic energy of oscillations into the volume of the sealed evacuated chamber 3, filled with electrically insulating liquid.
• the pressure in the sealed evacuated chamber 3 is equalized with the downhole pressure by the operation of the piston mechanism 5, compressed by a spring, and the basic radiating elements are flat rod-shaped magnetostrictive transducers 9 made of Permendur.
• the magnetostrictive transducers 9 produce longitudinal pulsating oscillations (along the axis of the well), the radiating ends of neighbouring magnetostrictive transducers 9 oscillating towards one another (this arrangement may be called“opposing"), so that the effect of compression and expansion of the acoustic medium between the ends is transformed predominantly into radial oscillations of the medium (Fig. 2)
• the energy of the elastic waves is entirely transferred to the housing 1 of the emitter, the wall thickness of which is less in the area where the magnetostrictive transducers 9 are placed than in the other part.
• this section with the magnetostrictive transducers 9 arranged in it, is made to be evacuated and entirely filled with an electrically insulating liquid, reliable operation of the emitter is ensured regardless of the nature of the liquid phase filling the well, whereas, in the absence of designed protection of the emitter, a parameter of the fluid such as its corrosive action may have a significant effect on the operating parameters of the emiter.
• the degassing of the electrically insulating liquid due to the evacuation of the internal volume increases the reliability and ensures efficient operation of the emitter when the well is filled with any fluid.
• the energy of the elastic oscillations radiated by the housing 1 is transmitted into the well space in which the interaction of the pressure waves and the formation of the total acoustic field in the well and in the well bottom zone takes place.
• the magnetostrictive transducers 9 operate in a frequency range of 5-35 kHz [2].
• the intrinsic (resonance) frequencies of a magnetostrictive transducer 9, that is to say in the absence of an external load on its radiating surface, are determined by the equation:
• c the propagation velocity of longitudinal waves in the material in the absence of a magnetic field
• Permendur which is commonly used in practice
• c 5000 m/s
• L the length of the transducer.
• f fo
• L 12.5 cm.
• the electrical power of the generator supplied to the transducer is:
• Ai is the radiation surface area of the core

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Geology (AREA)
• Mining & Mineral Resources (AREA)
• Physics & Mathematics (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Transducers For Ultrasonic Waves (AREA)
• Geophysics And Detection Of Objects (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Cites Families (12)

• 2019
  • 2019-07-23 RU RU2019123136A patent/RU2717845C1/ru active
• 2020
  • 2020-07-13 WO PCT/EP2020/069793 patent/WO2021013613A1/en unknown
  • 2020-07-13 EP EP20742210.6A patent/EP4004332A1/de not_active Withdrawn

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