U.S. patent application number 15/300802 was filed with the patent office on 2017-01-19 for a sonic/ultrasonic-assisted method for the compaction and injection of granular slurries and pastes in the subsurface.
The applicant listed for this patent is Badger Explorer ASA. Invention is credited to Oystein Larsen, Sakalima George Sikaneta.
Application Number | 20170016296 15/300802 |
Document ID | / |
Family ID | 54239424 |
Filed Date | 2017-01-19 |
United States Patent
Application |
20170016296 |
Kind Code |
A1 |
Larsen; Oystein ; et
al. |
January 19, 2017 |
A sonic/ultrasonic-assisted method for the compaction and injection
of granular slurries and pastes in the subsurface
Abstract
A compaction and/or hydro fracture generation device (10)
comprises a compression device (11), a vibration generator device
(12) arranged to generate vibrations in the ultrasonic frequency
range, and a power source connected to the vibration generator.
Inventors: |
Larsen; Oystein; (Stavanger,
NO) ; Sikaneta; Sakalima George; (Stavanger,
NO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Badger Explorer ASA |
Stavanger |
|
NO |
|
|
Family ID: |
54239424 |
Appl. No.: |
15/300802 |
Filed: |
March 27, 2015 |
PCT Filed: |
March 27, 2015 |
PCT NO: |
PCT/EP2015/056752 |
371 Date: |
September 30, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 7/26 20130101; E21B
43/003 20130101; E21B 43/26 20130101; E21B 47/13 20200501; E21B
41/0057 20130101; E21B 7/24 20130101; E21B 43/267 20130101; E21B
28/00 20130101 |
International
Class: |
E21B 28/00 20060101
E21B028/00; E21B 7/24 20060101 E21B007/24; E21B 43/26 20060101
E21B043/26; E21B 43/00 20060101 E21B043/00; E21B 41/00 20060101
E21B041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 3, 2014 |
NO |
20140429 |
Claims
1. Subsurface material compaction device comprising: a compression
device, a vibration generator device arranged to generate
vibrations in the subsurface material, which vibrations are in the
ultrasonic frequency range, and a power source connected to the
vibration generator.
2. Compaction device according to claim 1, where the compression
device is a moving piston plate.
3. Compaction device according to claim 2, where the vibration
generator device is a sonic or ultrasonically vibrating surface
that is affixed to the moving piston-plate.
4. Compaction device according to claim 1, where the compression
device is a plate connected to or integrated in the vibration
generator device.
5. Compaction device according to one of the previous claims, where
the vibration generator device is connected to the compression
device and arranged to generate vibrations in the compression
device.
6. Compaction device according to claim 5, where the vibration
generator device generates high-power vibrations of >1 kW and
>8 kHz frequency.
7. Compaction device according to claim 5, further comprising a
controller unit connected to the vibration generator to control the
vibration generator.
8. Compaction device according to claim 5, where the vibration
generator is a piezoelectric or magnetostrictive transducer.
9. Compaction device according claim 5, where the vibrations are in
the area 20 kHz and above.
Description
[0001] This application regards a compaction device for efficient
compaction and/or hydro fracture generation.
[0002] During the operation of the Badger Explorer, a drill tool of
the type described in NO312110, a hole is drilled into a subsurface
formation and the waste rock from the drilling process is deposited
as a plug behind the advancing tool. Due to dilatancy that occurs
when the formation is cut, the volume of the material that must be
deposited behind the tool is greater than that which was cut. The
waste material must be treated in such a manner that it recovers
its original density and/or accommodation space for the expanded
volume must be made within the formation.
[0003] A similar problem is faced by the mining industry in where
mineral ores are removed from the subsurface, processed, and the
waste rock is then used to backfill the subsurface tunnels and
caverns from which it was excavated.
[0004] A similar problem is also encountered in the field of thick
slurry injection in which produced solid wastes from hydrocarbon
wells are re-injected into subsurface formations.
[0005] Simple compression of the waste will expel some of the
fluids (liquids and gases) that are present in the pore space, but
this will in many cases not be sufficient.
[0006] Compaction of mine back-fill using lower frequency vibrating
compactors has been performed at surface for the mining industry,
and has likely been used subsurface. Densification of surface
deposits using an experimental low-power ultrasonic compactor for
geotechnical ground improvement has also been reported (Towhata,
I., Geotechnical Earthquake Engineering, Springer-Verlag 2008, pp
608).
[0007] The object of the invention is to provide a device and
method for efficient compaction and/or hydro fracture generation
which alleviates at least some of the above mentioned problems and
challenges.
[0008] The object of the invention is achieved by means of the
features of the patent claims.
[0009] The material which is to be compacted, for example for the
applications described above, will in this description be referred
to as "paste". This term is meant to describe any material which is
to be compacted or injected, for example in the underground.
[0010] A potential application of the described technology that
does not rely on the increased ability to compact, but rather on
improved injection performance, is in the field of hydro fracture
and hydraulic stimulation, such as in wellbores to create small
fractures (typically less than 1 mm), along which fluids such as
gas, petroleum, uranium-bearing solution, and brine water may
migrate to the well. By applying vibrations at the injection point
during a stimulation, the skin friction of the well will be reduced
and vibration during the emplacement of proppant will allow wider
aperture and hence more productive stimulation.
[0011] The object of the invention is achieved by a combination of
two mechanisms: compression and high frequency vibration.
[0012] It is well established that vibrating a dry or saturated
granular mixture will cause a drop in the viscosity of the mixture.
The decrease in the resistance to flow is related to the frequency
of the vibrations, the size of the particles in the mixture, and
the amplitude of the vibrations (Melosh, Journal of Geophysical
Research, 1979).
[0013] High power (>10 W/cm2)-high frequency (>8 kHz)
ultrasonic vibrations applied to a surface which is used for
compacting, will thus fluidize the paste and allow pore fluids to
be expelled until the paste has been compressed to its jamming
point. Jamming is the physical process by which some materials,
such as granular materials, glasses, foams, and other complex
fluids, become rigid with increasing density. The density at which
systems jam is determined by many factors, including the shape of
their components, the deformability of the particles, frictional
interparticle forces, and the degree of dispersity of the system.
The overall shape of the jamming manifold may depend on the
particular system.
[0014] The jamming point for the ultrasonically vibrated paste will
occur at a higher density than the non-vibrated paste, leading to a
higher final density of the material, for example in a compacted
plug.
[0015] Fluidization and energizing of the paste will allow it to
enter and widen small apertures and hydrofractures that would
otherwise be too thin to accommodate the material.
[0016] In one embodiment a compaction device according to the
invention comprises a compression device, a vibration generator
device arranged to generate vibrations in the ultrasonic frequency
range, and a power source connected to the vibration generator.
[0017] The compression device is a device that compresses the
material, ie. the paste, to as compact condition as possible. The
compression device can be any suitable device which is capable to
compress the material in question, and is in one embodiment a
moving piston plate. The piston can be a pneumatic or hydraulic
piston with a plate mounted at its further end perpendicular to the
movement direction of the piston. The extension of the piston
towards the paste causes the compression of the paste.
[0018] The vibrator generator device is a device adapted to
generate vibrations of a desired frequency in the paste in order to
achieve the fluidization effect described above. In one embodiment
the vibration generator device is a sonic or ultrasonically
vibrating surface that is affixed to the moving piston-plate. The
vibrations will then be transferred via the piston plate and then
relayed into the paste, causing the desired vibrations in the
paste. The vibration generator device may also be connected to any
other kind of compression device and arranged to generate
vibrations in the compression device or be integrated in the
compression device. For example the vibrator generator may be a
vibrating surface or plate or be connected to a surface or plate,
for example a plate constituting the compression device where the
plate not necessarily is a piston plate. In one embodiment the
compression device and the vibrator generator device is integrated
as one device, and the compression is performed by the vibrations.
The vibration generator is a piezoelectric or magnetostrictive
transducer. In other embodiments, the vibration generator may send
the vibrations directly into the paste.
[0019] In order to achieve the desired vibration characteristics,
the compaction device may comprise a controller unit connected to
the vibration generator to control the vibration generator.
[0020] The characteristics of the vibrations, such as frequency and
amplitude of the vibrations generated by the vibration generator
device may be tuned to provide the desired frequency and amplitude
in the paste by taking into account the dampening and other effects
caused by the connected elements such as piston plate, piston,
etc.
[0021] In one embodiment the vibration generator device generates
high-power vibrations of >1 kW and >8 kHz frequency. In
another embodiment, the vibrations may be in the area 20 kHz and
above. The compaction device may also be arranged to be able to
vary the frequency, or adapt the frequency to the material to be
compacted. The compaction device may in this respect comprise
sensor devices which can monitor the type of material/paste to be
compacted, and the controller unit may be programmed to adapt the
vibration characteristics to the present material.
[0022] The power source for the compaction device may be any
suitable power source, such as a wired power source, or the device
may receive power from a connected or adjacent device, or be
self-powered.
[0023] The invention will now be described in more detail by means
of an example and with reference to the accompanying figures.
[0024] FIG. 1 illustrates an example of a compaction device used
for efficient compaction
[0025] FIG. 2 illustrates an example of a compaction device used
for hydro fracture generation.
[0026] FIG. 1 illustrates a compaction device 10 according to the
invention which comprises a compression device 11, in the form of a
piston 13 and a connected moving piston plate 14. A vibration
generator device 12 is arranged to generate vibrations in the
ultrasonic frequency range, and is a sonic or ultrasonically
vibrating surface 12 that is affixed to the moving piston-plate 14.
The vibration surface 12 can for example comprise a piezoelectric
or magnetostrictive transducer.
[0027] The vibrations cause fluidization and particle
reorganization that allows the mixture to expel fluids (liquids
and/or gases) more efficiently, thus providing the desired
compression.
[0028] The vibration generator device is connected to a power
source (not shown) for providing power for generation of the
vibrations. In the case that the compaction device is used in a
drill tool of the type described in NO312110 (Badger Explorer), the
power source can be arranged at the earth's surface and power
transferred via the spooled cable, through which power is supplied
to the tool and data transferred to surface.
[0029] FIG. 2 illustrates an example of a compaction device used
for hydro fracture generation. This is a technique to create small
fractures (typically less than 1 mm), along which fluids such as
gas, petroleum, uranium-bearing solution, and brine water may
migrate to the well. Hydraulic pressure is removed from the well,
then small grains of proppant (sand or aluminium oxide) hold these
fractures open once the rock achieves equilibrium. The technique is
very common in wells for shale gas, tight gas, tight oil, and coal
seam gas and hard rock wells. This well stimulation is usually
conducted once in the life of the well and greatly enhances fluid
removal and well productivity, but there has been an increasing
trend towards multiple hydraulic fracturing sessions as production
declines.
[0030] In the example of FIG. 2 the compaction device 20 comprises
a compression device 21, for example similar to in FIG. 1. A
vibration generator device 22 is arranged to generate vibrations in
the ultrasonic frequency range, and is a sonic or ultrasonically
vibrating surface 22 that is affixed to the compression device 21.
The vibration surface 22 can for example comprise a piezoelectric
or magnetostrictive transducer. Vibrations at an injection point
during a stimulation are produced by means of the vibrator
generation device 22. This reduces the skin friction of the well
and provides fractures 23 in the ground into which proppant may
migrate. As mentioned above, this will allow wider apertures and
hence more productive stimulation.
* * * * *