Field of Invention
[0001] This invention relates to downhole cleaning using an ultrasonic device. More particularly,
this invention relates to downhole cleaning utilizing ultrasonic generator(s) powered
by piezoelectric element(s), not requiring external electric power. The ultrasonic
generator and piezoelectric element are placed within the completion equipment and
the piezoelectric element(s) is normally in an unstrained state, generating no electrical
current, but when subjected to mechanical force, it generates electricity to power
the ultrasonic device.
Background of the Invention
[0002] Well productivity is often impaired by fine particles lodged in restrictions or caked
on the wellbore. Chemical cleaning has limited effectiveness in removal of these materials.
Ultrasonic devices have been shown to enhance cleaning and particle separation from
liquids. Current downhole ultrasonic cleaning devices are powered by external electric
sources connected to the device by wires or cables.
[0003] It is known to enhance well cleaning using acoustic excitation.
U.S. 4,280,557 discloses an apparatus for cleaning an extended number of apertured portions of the
lower region of an oil well casing, which includes a sonic oscillator, a stem member
in the form of an elongated elastic tube which runs along said extended number of
apertured portions, said oscillator to be attached to the top end of said stem member
in the region of the apertured portions to be cleaned, and means for driving said
oscillator.
U.S. 5,458,860 discloses the use of sonic energy to enhance the removal of alkaline earth scale
using an aqueous solution having a pH of about 8 to 14 and comprising a chelating
agent.
[0004] The use of an external electric power source connected by a cable to power an electroacoustic
ultrasonic energy producing transducer is disclosed in
U.S. 5,109,922 which describes a power supply adjacent to the well and an electrical conductor means
of a length sufficient to extend from ground level to at least the level of oil in
the well for conducting alternating electrical power from said power supply to said
transducer.
[0005] U.S. 5,184,678 discloses an apparatus for stimulating fluid production in a producing well wherein
a well stimulating tool comprising a sealed tool housing with an acoustic transducer
in the housing is run into a producing well on an electric wireline and placed at
a depth opposite perforations in the producing zone. Similarly,
U.S. 5,595,243 discloses a method and apparatus for cleaning the wellbore and the near wellbore
region in which a sonde is provided which is adapted to be lowered into a borehole
and which includes a plurality of acoustic transducers arranged around the sonde,
and wherein electrical power provided by a cable is converted to acoustic energy.
[0006] The use of mechanical coupling to produce low frequency waves is disclosed in
U.S. 4,469,175, which describes a mechanoacoustic transducer, which comprises a plurality of circumferentially
spaced contiguous vibratile plate members, which are driven in phase by a rotating
cylindrical cam. The cam is shaped to provide radial oscillatory displacements of
the vibratile plates of sufficient amplitude to generate acoustic power density levels
in liquids.
[0007] The use of fluid coupling to produce vibration to enhance well cementing is disclosed
in
U.S. 4,658,897. The transducer members are within a sleeve that is filled with oil and communicates
vibrations from the transducer members.
[0008] U.S. 4,788,467 discloses in combination a housing, at least one transducer disposed in the housing
and having properties of receiving electrical energy and converting the electrical
energy into expansions and contractions of the transducer for the pumping of oil in
the oil well in accordance with such expansions and contractions, passages extending
into and out of the housing at opposite ends of the housing at a position below the
transducer, a piston disposed in the housing for movement in accordance with the pressure
of the fluid in the oil well, and a spring supported between the piston and the housing
for compression and expansion to inhibit any cavitation of the oil in the oil well
as a result of such expansion and contraction of the transducer and as a result of
changes in the temperature of the oil in the oil well.
[0009] U.S. 5,554,922 discloses a system for the conversion of pressure fluctuations prevailing in a fluid
distribution piping system into electrical energy,
characterized in that it includes a casing, at least one chamber formed in the casing which may be linked
to a fluid system and which is limited on one side by a wall which may be moved back
and forth under the influence of the pressure prevailing in the fluid system, and
at least one apparatus which is connected to the movable wall and which converts the
mechanical energy transmitted by this into electrical energy.
[0010] US patent application
US2002/0070017 discloses a vibrating well cleaning device which is suspended in a wellbore from
a electrical power supply cable which has to be replaced after each cleaning operation.
US patent application
US2003/0196816 discloses a vibrating well cleaning device which is actuated by turbulence in well
flow.
[0011] As mentioned above, current downhole ultrasonic cleaning devices are powered by external
electric sources connected to the device by wires or cables. It would be extremely
valuable in the art if there were an alternative, lower cost, simpler way to power
such devices using mechanical force to generate electrical power using a piezoelectric
device. In many industrial applications, particularly those involved in the drilling,
completion, and workover of oil and gas production wells, equipment normally used
in these applications is already designed to apply large magnitude, controlled loads
or stresses from the surface or other remote location to the equipment at the bottom
of the well. On the other hand delivering external electrical power as required in
the prior art requires additional equipment not normally installed in the well. The
prior art does not recognize the opportunity to use the available mechanical force
to create electricity to power the downhole ultrasonic device.
Summary of the Invention
[0012] In accordance with the present invention there is provided a cleaning apparatus for
dislodging caked particles from a tubing in a wellbore as claimed in claim 1 and a
method of producing crude oil and/or gas through a tubing in a wellbore from which
caked particles are dislodged by means of the cleaning apparatus according to claim
1.
Brief Description of the Diagrams
[0013]
Figure 1 is a block diagram of the invention configured for temporary insertion into
the well or other structure of fixed diameter with a packer on tubing.
Figure 2 is a diagram of the invention configured for permanent installation in the
wellbore and activation by inserted tubing.
Figure 3 is a graph showing voltage vs. current for a piezo generator.
Figures 4(a) and 4(b) are diagrams of compression and tension generators, respectively.
Figures 5(a) and 5(b) are diagrams of parallel and transverse shear generators, respectively.
Figures 6(a) and 6(b) are diagrams of series and parallel bending generators, respectively.
Detailed Description of the Invention
[0014] Piezoelectric materials transform energy from mechanical to electrical and vice-versa.
Piezoelectric materials produce an electric field when exposed to a change in dimension
caused by an imposed mechanical force (mechanical to electrical conversion) and conversely,
an applied electric field will produce a mechanical stress (electrical to mechanical
conversion). These materials can be used for sensing purposes, including actuator
and sensor applications.
[0015] In the present invention a downhole ultrasonic well cleaning device is powered by
an apparatus that converts mechanical force into electrical energy, preferably a piezoelectric
generator. Both are installed or inserted within the completion equipment of any structure
where the caking of particles may affect productivity. The preferred application is
in cleaning wells and subterranean formations. The ultrasonic generator and piezoelectric
element would be placed within the completion equipment (e.g. pipeline, tubing, packer,
sand control screen, or other element) of a pipeline or subterranean well such as
those used for oil or gas production. Figure 1 illustrates a configuration for temporary
insertion in the well. The mechanical electrical converter
1, ultrasonic generator
2, and the ultrasonic sonde
3 are inserted on the end of a temporarily installed tubing
4, which is anchored in place by a temporary packer sealing element
5. Tension or compression as denoted by the arrow
6 is applied to this tubing from an oil field drilling rig, workover rig, or workover
hoist.
[0016] Figure 2 illustrates a configuration for permanent installation. In this case the
mechanical electrical converter
1, ultrasonic generator
2, and the ultrasonic sonde
3 are permanently affixed to the permanent production tubing of the well
4 which may be affixed with a permanent packer sealing element
5. In this configuration the force
6 is applied to a second tubing
7 that is temporarily inserted into the bore of the permanent tubing
4. In this configuration a flow passage
8 exists. The principle differences between the two are the passageway to allow fluid
production in the second example and the arrangement of packers and alignment of tubing
to allow easy removal in the first application. Other configurations could be envisioned
but these diagrams capture the key elements of two broad classes.
[0017] The piezoelectric element of the mechanical electrical converter is normally in a
relaxed (unstrained) state and generates no electrical current, however the piezoelectric
element(s) are mounted or inserted in the pipeline or well equipment in a manner which
allows the operator to apply mechanical force as required. When the operator desires
to generate ultrasonic excitation to enhance well cleaning, mechanical force would
be applied to the piezoelectric element to generate electricity to power the ultrasonic
sonde.
[0018] Ultrasonic sondes convert electrical energy to ultra high frequency pressure oscillations
when electrical energy is applied to the sonde at its operational resonant frequency.
The operational resonant frequency and range of the sonde is determined by its design,
specifically geometry and materials of construction. Various equipment manufacturers
accomplish this in a number of ways. The present invention is not intended to be limited
to any particular ultrasonic sonde. Suitable acoustic sondes and transducers are described,
for example, in
U.S. 5,595,243 and
U.S. 5,184,678.
[0019] The ultrasonic generator converts normal sources of electricity, such as direct current
from batteries or alternating current, typically 20 to 80 Hz, to ultra high frequency
alternating current to excite the operational resonant frequency of the ultrasonic
sonde. The principles to be applied in designing a suitable generator for this application
are known to those skilled in the art. Examples are given in
U. S. 5,184,678 and
U. S. 5,595,243. Use of direct current from a battery has been revealed by
Y. Bar-Cohen, S. Sherrit, B. Dolgin, T. Peterson, D. Pal and J. Kroh, "Ultrasonic/Sonic
Driller/Corer (USDC) With Integrated Sensors," New Technology Report, Submitted on
August 30, 1999. Docket No. 20856, Item No. 0448b, November 17, 1999. U.S. Provisional Patent, filed
on May 3, 2000, Application No.
60/201,650. The ultrasonic generator receives input signals from the piezoelectric element when
it is placed in tension or compression or it is otherwise strained.
[0020] The device for converting mechanical to electrical energy revealed in this invention
is based on the phenomenon that piezoelectric elements can be used to generate electrical
power when they are subjected to mechanical force, i.e. when they are placed in compression
or tension and when they are strained. Piezoelectric materials include many polymers,
ceramics, and molecules, such as water, which are permanently polarized. Suitable
piezoelectric materials in the present invention for producing an electric field as
the result of an imposed mechanical force include, for example, but are not limited
to ceramic, quartz (SiO
2), barium titanate (BaTiO
3), lithium niobate, polyvinyledene difluoride (PVDF), and lead zirconate titanate
(PZT). (See:
http://www.mse.cornell.edu/courses/engril 11//piezo.htm) They are ceramic materials manufactured of specific materials and under specific
conditions to impart piezoelectric properties. Other classes of materials, such as
certain minerals and combinations of metal and minerals may also create the same effect
and could be used in this invention. The ceramic materials are preferred because their
properties are more reproducible and controllable. The property that is exploited
in this invention is that when a mechanical force is applied, placing the piezoceramic
in tension, compression, or inducing strain, an electrical charge is generated. The
charge generated is proportional to the force applied. If designed appropriately this
charge will induce an electromotive force that can supply current to power electrical
devices like the generator and sonde in this invention.
[0021] The material to be used in this invention will be chosen based on the relationship
between the properties of the material, the mechanical design of the installation
or apparatus delivering force, and the electrical properties (voltage and power) required
to power the sonde. These are captured schematically in Figure 3, which illustrates
a typical curve of voltage produced versus current for a piezo ceramic. The value
of voltage produced for a given mechanical loading is a property of the piezo ceramic
know in the industry as the "g" constant. This constant is commonly known for commercially
available materials suitable for this application. The maximum voltage (denoted V
oc in Figure 3) is achieved if the circuit is open, i.e. no current or power is drawn
from the device. As current is drawn from the device the voltage is reduced but power
is generated. The maximum current is available if the circuit is closed (denoted I
cc in Figure 3). The appropriate operating point (A in Figure 3) for the piezo ceramic
defined by a particular stress (S
op in Figure 3) above the threshold stress for the material (S
1 in Figure 3) will deliver the required voltage and current to the generator to power
the sonde at the mechanical stress the apparatus is designed to impart.
[0022] The piezoelectric element in this invention is placed in a mechanical element or
housing within the wellbore or inserted tubing such that mechanical force imposed
on the tubing is transmitted to the element. As illustrated in Figures 4-6 this mechanical
force could be used to place the piezo electric element in tension or compression
or to bend it. Each of these modes of operations may be useful in specific designs.
For example a simple tension or compression device, as illustrated in Figures 4(a)
and (b), would be applicable in the application illustrated in Figure 1 where the
apparatus is placed symmetrically in the center of the well. A shear type device as
illustrated in Figures 5(a) and (b) would be more applicable in the apparatus illustrated
in Figure 2 where the ultrasonic apparatus and mechanical - electrical energy converter
is place asymmetrically on one side of the well tubing.
[0023] Single sheets of piezo can be energized to produce motion in the thickness, length,
and width directions. They may be stretched or compressed to generate electrical output.
Double or multiple ceramic elements may be used in series or parallel as required
to generate the required voltage and power. Other alternatives are bending or extension
of two-layer generators including extension and bending generators. Applying mechanical
stress to a laminated two layer element results in electrical generation depending
on the direction of the force, the direction of polarization, and the wiring of the
individual layers. In the case of an extension generator, when a mechanical stress
causes both layers of a suitably polarized 2-layer element to stretch (or compress),
a voltage is generated which tries to return the piece to its original dimensions.
Essentially, the element acts like a single sheet of piezo. The metal shim sandwiched
between the two piezo layers provides mechanical strength and stiffness. Any of these
or combinations thereof may be applied to deliver the voltage and power required to
drive the sonde.
[0024] In multi-layer generators, one example of which is a stack generator, the stack,
which comprises a large number of piezo layers, is a very stiff structure with a high
capacitance. It is suitable for handling high force and collecting a large volume
of charge.
[0025] Series operation refers to the case where supply voltage is applied across all piezo
layers at once. The voltage on any individual layer is the supply voltage divided
by the total number of layers. A 2-layer device wired for series operation uses only
two wires, one attached to each outside electrode (figure 6a).
[0026] Parallel operation refers to the case where the supply voltage is applied to each
layer individually. This means accessing and attaching wires to each layer. A 2-layer
bending element wired for parallel operation requires three wires; one attached to
each outside electrode and one attached to the center shim (Figure 6b).
[0027] In the present invention the ultrasonic generator and piezoelectric elements would
be attached or installed in a structure or wellbore during completion. This could
be accomplished in a number of ways, as would be apparent to those skilled in the
art and the present invention is not intended to be limited to a particular method.
The elements can be secured by, for example, welding, or cement adhesions, or by screwing
in mounting brackets. (See:
http://www.loadmonitors.com/services.htm)
[0028] The mechanical force could be applied by several means, including, but not limited
to: 1) Placing the well tubing in tension or compression; 2) Use of a second tubing
inserted into or around the wells permanent tubing; or 3) Use of a mechanical device
inserted into the wellbore on a non-conducting wire.
[0029] In another embodiment the apparatus could be situated on sectional tubing, coiled
tubing, or non-electric wireline, then inserted into the wellbore and actuated by
mechanical force, by one of the methods described above.
[0030] As mentioned above, the mechanical force could be applied by, for example: 1) Placing
the well tubing in tension or compression; 2) Use of a second tubing inserted into
or around the wells permanent tubing; or 3) Use of a mechanical device inserted into
the wellbore on a non-conducting wire. Well tubing can be placed in compression using
a packer or other tubing anchor to lock the tubing in place. Such packers and tubing
anchors are commercial items available from a variety of vendors and widely used in
well construction activities, (See, for example,
http://www.bakerhughes.com/bot/service tools/index.htm) and can be placed in tension or compression using mechanical equipment normally
available on rigs and hoists used for well operations. The techniques used to place
tubing in compression or tension in a controlled manner are often practiced by those
skilled in the art using established techniques. The piezoelectric elements could
be situated such that when either tension or compression of the tubing occurs, the
piezoelectric element is subjected to force, thus generating electric power for the
ultrasonic transducer.
[0031] In another embodiment, a second tubing, of slightly smaller or larger diameter could
be inserted into or around permanent tubing, and as it moves it would come in contact
with the piezoelectric elements secured in the completion equipment, to create mechanical
force, which is converted to electric power for the ultrasonic generator.
[0032] In yet another embodiment, a mechanical device could be introduced into the wellbore
on a non-conducting wire, and as it comes into contact with the piezoelectric element(s),
the element(s) would be bent or displaced.
[0033] Also within the concept of the present invention the ultrasonic sonde and piezoelectric
mechanical to electrical converter could be situated on sectional tubing, or coiled
tubing, and subject to compression or tension loads using the equipment and methods
described above.
[0034] Alternatively, a non-electric wireline could be inserted into the wellbore with a
device designed to catch the mechanical electrical converter or an attachment to it.
The operator would then pull on the non-electric wireline to apply a tension load
to the mechanical electrical converter. This method would be limited by the strength
of the non-electric wireline.
[0035] When mechanical force is applied to the piezoelectric generator, the movement results
in an electrical voltage which can be measured at the electrical terminals of the
piezoelectric converter and used to power the ultrasonic sonde by suitable electronics,
referred to herein as the generator, which are not the object of the present invention.
[0036] This method can be used to clean enclosed tanks or vessels where access for other
methods is limited.
[0037] It can be used to clean water production or injection wells or wells used for the
injection of steam or production of hot water or steam from subterranean geothermal
deposits.
[0038] Variations might include:
- Positioning of the respective elements (generator or oscillator) with respect to each
other.
- Nature of the electrical circuitry used to transmit the electrical energy generated
to the sonic oscillator.
- Materials of construction of the various elements.
- Frequency of operation of the ultrasonic sonde.
- Whether the sonde is operated in a steady or pulsed mode.
- Characteristics of the electrical energy generated - voltage, current, and power.
- Methods for positioning the elements in the structure to be cleaned.
- Size of the various pieces of equipment.
- The orientation of the equipment in the enclosure to be cleaned. This includes the
direction in which the respective elements are pointed and whether they are mounted
symmetrically or asymmetrically within the enclosure.
- In cases where a tubing element or non-electric wireline element is used to apply
mechanical force it may be inserted in the bore of a larger tubing or alternatively
in the annulus between concentric tubing or casing strings.
- Mechanical force may be applied to the element from any direction.
[0039] The invention as described is intended only as a means of illustration and should
not be construed as limiting the scope of the invention in any way.
1. A cleaning apparatus for dislodging caked particles from a production tubing (4) in
a wellbore comprising:
at least one ultrasonic generator (2) for conditioning electrical energy to excite
an ultrasonic energy sonde (3); and
at least one ultrasonic energy sonde (3), which while excited, converts the electrical
energy into ultrasound energy for dislodging caked particles,
characterized in that the apparatus further comprises at least one converter apparatus (1), which upon
application of a tension or compression force converts mechanical energy into the
electrical energy and the tension or
compression force is applied to the at least one converter apparatus (1) by a second
tubing (7) which is inserted into or around the production tubing (4) or by a mechanical
device which is inserted into the well on a non-conducting wire.
2. The cleaning apparatus of claim 1 wherein the at least one converter apparatus (1)
is a piezoelectric generator (1), which is placed in a mechanical element or housing
within the wellbore or inserted production tubing (4), such that tension or compression
force imposed on the second tubing (7) or wire is transmitted to the element.
3. The cleaning apparatus of any of claims 1 or 2 wherein the at least one ultrasonic
generator (2) and the at least one converter apparatus (1) are placed in a packer
(5), or sand control screen that form part of the production tubing (4).
4. The cleaning apparatus of any one of claims 1 or 2 wherein the at least one ultrasonic
generator (2) and the at least one converter apparatus (1) are secured on an instrument
inserted into the production tubing (4).
5. The cleaning apparatus of any one of claims 2-4 wherein the piezoelectric generator
(1) is a single layer generator, a two-layer generator, or a stacked generator and
is made of a material selected from ceramic, quartz (SiO2), barium titanate (BaTiO3), lithium niobate, polyvinyledene difluoride (PVDF), and lead zirconate titanate
(PZT).
6. The cleaning apparatus of any one of claims 2-5 wherein the piezoelectric generator
(1) is a simple beam mount or a cantilever mount.
7. The cleaning apparatus of any one of claims 1-6 wherein the tension or compression
force is applied to the at least one converter apparatus (1) by placing the second
tubing (7) in tension or compression.
8. The cleaning apparatus of claim 1-7 wherein the non-conducting wire is a wireline
jar.
9. The apparatus of any one of claims 1-8 wherein the at least one converter apparatus
(1) is isolated from fluids and fluid pressure to ensure it only activates when desired.
10. A method of producing crude oil and/or gas through a production tubing (4) in a wellbore
from which caked particles are dislodged by means of the cleaning apparatus according
to claim 1.
1. Reinigungsvorrichtung zum Lösen von zusammengebackenen Teilchen aus einem Förderrohr
(4) in einem Bohrloch, mit:
zumindest einem Ultraschallgenerator (2) zum Konditionieren elektrischer Energie zum
Anregen einer Ultraschallenergiesonde (3); und
zumindest einer Ultraschallenergiesonde (3), die im Anregungszustand elektrische Energie
in Ultraschallenergie zum Lösen der zusammengebackenen Teilchen umwandelt,
dadurch gekennzeichnet, daß die Vorrichtung ferner zumindest eine Wandlervorrichtung (1) aufweist, die beim Aufbringen
einer Zug- oder Druckkraft mechanische Energie in elektrische Energie umwandelt, und
die Zug- oder Druckkraft auf zumindest eine Wandlervorrichtung (1) durch ein zweites
Rohr (7), welches in oder um das Förderrohr (4) eingesetzt wird, oder durch eine mechanische
Vorrichtung aufgebracht wird, die in einen Schacht an einem nichtleitenden Draht eingesetzt
wird.
2. Reinigungsvorrichtung nach Anspruch 1, bei welcher die zumindest eine Wandlervorrichtung
(1) ein piezoelektrischer Generator (1) ist, der in einem mechanischen Element oder
Gehäuse innerhalb des Bohrloches angeordnet oder in das Förderrohr (4) eingesetzt
wird, derart, daß die auf das zweite Rohr (7) oder den Draht aufgebrachte Zug- oder
Druckkraft auf das Element übertragen wird.
3. Reinigungsvorrichtung nach Anspruch 1 oder 2, bei welcher der zumindest eine Ultraschallgenerator
(2) und die zumindest eine Wandlervorrichtung (1) in einem Packer (5) oder in einem
Sandkontrollgitter, welches Teil des Förderrohres (4) bildet, angeordnet wird.
4. Reinigungsvorrichtung nach einem der Ansprüche 1 oder 2, bei welcher der zumindest
eine Ultraschallgenerator (2) und die zumindest eine Wandlervorrichtung (1) an einem
Instrument befestigt sind, das in das Förderrohr (4) eingesetzt wird.
5. Reinigungsvorrichtung nach einem der Ansprüche 2-4, bei welcher der piezoelektrische
Generator (1) ein einlagiger Generator, ein zweilagiger Generator oder ein Stapelgenerator
ist und aus einem Material besteht, das aus Keramik, Quarz (SiO2), Bariumtitanat (BaTiO3), Lithiumniobat, Polyvinylidendifluorid (PVDF) und Blei-Zirkonat-Titanat (PZT) gewählt
ist.
6. Reinigungsvorrichtung nach einem der Ansprüche 2-5, bei welcher der piezoelektrische
Generator (1) eine einfache Balken- oder Auslegertragvorrichtung aufweist.
7. Reinigungsvorrichtung nach einem der Ansprüche 1-6, bei welcher die Zug- oder Druckkraft
auf die zumindest eine Wandlervorrichtung (1) aufgebracht wird, indem das zweite Rohr
(7) unter Zug oder Druck gesetzt wird.
8. Reinigungsvorrichtung nach einem der Ansprüche 1-7, bei welcher der nichtleitende
Draht ein Drahtleitungstopf ist.
9. Vorrichtung nach einem der Ansprüche 1-8, bei welcher die zumindest eine Wandlervorrichtung
(1) von den Fluiden und dem Fluiddruck isoliert ist, um sicherzustellen, daß sie nur
aktiviert wird, wenn dies erwünscht ist.
10. Verfahren zum Fördern von Rohöl und/oder Gas durch ein Förderrohr (4) in einem Bohrloch,
in welchem zusammenge-backene Teilchen mittels der Reinigungsvorrichtung nach Anspruch
1 gelöst werden.
1. Dispositif de nettoyage pour déloger des particules agglutinées d'une colonne de production
(4) dans un puits de forage comprenant :
au moins un générateur d'ultrasons (2) pour conditionner l'énergie électrique pour
exciter une sonde d'énergie à ultrasons (3) ; et
au moins une sonde d'énergie à ultrasons (3), qui,
lorsqu'elle est excitée, convertit l'énergie électrique en énergie ultrasonore pour
déloger les particules agglutinées,
caractérisé en ce que le dispositif comprend en outre au moins un dispositif de conversion (1), qui lors
de l'application d'une tension ou d'une force de compression convertit l'énergie mécanique
en l'énergie électrique et
la tension ou la force de compression est appliquée à l'au moins un dispositif de
conversion (1) par une seconde colonne (7) qui est insérée dans ou autour de la colonne
de production (4) ou par un dispositif mécanique qui est inséré dans le puits de forage
sur un câble non conducteur.
2. Dispositif de nettoyage selon la revendication 1, dans lequel l'au moins un dispositif
de conversion (1) est un générateur piézoélectrique (1), qui est placé dans un élément
mécanique ou logement à l'intérieur du puits de forage ou de la colonne de production
insérée (4), de telle sorte que la force de tension ou de compression exercée sur
la seconde colonne (7) ou le câble est transmise à l'élément.
3. Dispositif de nettoyage selon l'une quelconque des revendications 1 ou 2, dans lequel
l'au moins un générateur d'ultrasons (2) et l'au moins un dispositif de conversion
(1) sont placés dans une garniture (5) ou une crépine d'élimination du sable qui font
partie de la colonne de production (4).
4. Dispositif de nettoyage selon l'une quelconque des revendications 1 ou 2, dans lequel
l'au moins un générateur d'ultrasons (2) et l'au moins un dispositif de conversion
(1) sont fixés sur un instrument inséré dans la colonne de production (4).
5. Dispositif de nettoyage selon l'une quelconque des revendications 2 à 4, dans lequel
le générateur piézoélectrique (1) est un générateur monocouche, un générateur bicouche
ou un générateur empilé et est fabriqué à partir d'un matériau choisi parmi la céramique,
le quartz (SiO2), le titanate de baryum (BaTiO3), le niobate de lithium, le difluorure de polyvinylidène (PVDF) et le titano-zirconate
de plomb (PZT).
6. Dispositif de nettoyage selon l'une quelconque des revendications 2 à 5, dans lequel
le générateur piézoélectrique (1) est un support formant poutre simple ou un support
en porte-à-faux.
7. Dispositif de nettoyage selon l'une quelconque des revendications 1 à 6, dans lequel
la force de tension ou de compression est appliquée à l'au moins un dispositif de
conversion (1) en plaçant la seconde colonne (7) sous tension ou compression.
8. Dispositif de nettoyage selon l'une quelconque des revendications 1 à 7, dans lequel
le câble non conducteur est un câble à coulisse.
9. Dispositif selon l'une quelconque des revendications 1 à 8, dans lequel l'au moins
un dispositif de conversion (1) est isolé des fluides et de la pression de fluide
pour s'assurer qu'il ne s'active que lorsqu'on le souhaite.
10. Procédé de production de pétrole brut et/ou de gaz à travers une colonne de production
(4) dans un puits de forage de laquelle des particules agglutinées sont délogées au
moyen du dispositif de nettoyage selon la revendication 1.