Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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PRODUCTION SYSTEM FOR PRODUCING HYDROCARBONS FROM A WELL
Field of the invention
The present invention relates to a production system for producing
hydrocarbons
from a well. Furthermore, the present invention relates to a well completion
comprising the production system according to the invention as well as to a
production method for the production of hydrocarbons from a well.
Background art
During oil and gas production, it is sometimes necessary to assist the
production
in a well due to a high hydro-static pressure. If the well itself is not
capable of
generating the adequate pressure to drive oil or gas to the surface, or the
well
has been deliberately killed, artificial lift may be used to lift the well
fluid at the
upper part of the well.
By submerging a pump into a well, the pump may be used to boost the pressure
or perhaps restart a dead well. The pump sets a plug or seal in the well and
pumps well fluid from one side of the plug to the other to overcome the static
pressure of the well fluid above the pump.
Other methods of artificial lifting use chemicals or gasses to provide the
lift
required to ensure an acceptable production outcome from the well. However,
the known solutions overcoming the static pressure of the well fluid use
external
energy sources.
Summary of the invention
It is an object of the present invention to wholly or partly overcome the
above
disadvantages and drawbacks of the prior art. More specifically, it is an
object to
provide an improved production system for producing hydrocarbons from a well
without using an artificial lift system, such as a pump, gas or chemicals.
The above objects, together with numerous other objects, advantages, and
features, which will become evident from the below description, are
accomplished
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by a solution in accordance with the present invention by a production system
for
producing hydrocarbons from a well, comprising
- a production casing,
- a monitoring unit adapted to measure a production outcome of the well,
- a first reservoir zone comprising at least a first fluid, extending along
and
outside part of the production casing,
- a second reservoir zone comprising at least a second fluid, extending
along and
outside another part of the production casing,
- a first inflow device arranged in the first reservoir zone, having a
first inflow
area and being adapted to let the first fluid into the production casing at a
first
volume rate, and
- a second inflow device arranged in the second reservoir zone, having a
second
inflow area and being adapted to let the second fluid into the production
casing at
a second volume rate,
wherein the first and second inflow areas of the inflow devices are
adjustable,
whereby the first and second inflow devices can be adjusted so that the first
volume rate is equal to or higher than the second volume rate.
Hereby, a production system is obtained wherein the energy in the reservoir
and
well is used for lifting the well fluid out of the well, substantially without
using
external energy sources.
In an embodiment, the inflow device comprises a first outer sleeve and a
second
inner sleeve movable in relation to each other, the first outer sleeve having
outer
inflow openings arranged in rows with a different number of openings in each
row, and the second inner sleeve having inner openings, whereby the inflow
area
of the inflow device is adjustable in that the inner openings of the second
inner
sleeve can be moved and aligned in relation to the outer openings of the first
sleeve.
Said inflow openings may be arranged in rows along the inflow device.
Furthermore, the inner openings may be arranged with a distance between them
in relation to the outer openings, whereby the inflow area of the inflow
device is
adjustable in that the inner openings of the second inner sleeve can be moved
and aligned in relation to the outer openings of the first sleeve.
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Moreover, the inner openings of the inner sleeve may be arranged with
predetermined circumferenctial distances between them so that each row of
outer inflow openings can optionally be opened or closed by moving the inner
sleeve.
In one embodiment, the second inner sleeve may be rotatably movable in
relation to the first outer sleeve.
In another embodiment, the inflow device may have an axial extension, and the
inner sleeve may be slidable in relation to the outer sleeve along the axial
extension.
Furthermore, the outer sleeve may have a recess in which the inner sleeve
slides
along the axial extension.
In yet another embodiment, the second sleeve may comprise recesses for
engaging with a key tool for adjusting the inflow device.
In yet another embodiment, the inner sleeve may be slidably movable in
relation
to the outer sleeve.
In addition, the production system as described above may further comprise a
monitoring unit adapted to measure a production outcome of the well.
Moreover, the monitoring unit may be adapted to measure a water content of the
production outcome so that the inflow devices may be adjusted to obtain an
optimum between production outcome and water content.
Also, the monitoring unit may be adapted to measure a volume rate of the
production outcome and/or a pressure at the top of the well so that the inflow
devices may be adjusted based on the volume rate and/or pressure measured at
the top of the well.
In one embodiment, the inflow devices may be manually adjustable.
In another embodiment, the inflow devices may be remotely adjustable.
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Furthermore, the inflow device may be operated by a magnetic source.
Moreover, the reservoir zones may be separated by annular barriers.
In an embodiment, the system may comprise a plurality of reservoir zones.
Further, a plurality of inflow devices may be arranged in the system and/or in
each reservoir zone.
Said plurality of inflow devices may be arranged in the system and/or in each
reservoir zone.
Also, the first fluid may be oil and the second fluid may be water or gas.
In addition, a valve may be arranged in one or more of the openings.
Furthermore, a screen may be arranged outside the openings.
In one embodiment, the inflow device may comprise a first packer, the second
sleeve may be arranged in a recess of the first sleeve, and the first packer
may
be arranged between the first sleeve and the second sleeve.
Furthermore, the packer may extend around the inner circumferential recess and
have an inner diameter which is substantially the same as that of the second
sleeve.
Moreover, the packer may have a number of through-going packer channels for
being aligned with first axial channels in the first sleeve.
In addition, the packer may be made of ceramics.
In an embodiment, the production casing may comprise annular barriers, each
annular barrier being adapted for being expanded in an annulus between the
production casing and an inside wall of a borehole downhole, and each annular
barrier comprising:
- a tubular part for mounting as part of the production casing,
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- an expandable sleeve surrounding the tubular part, each end of the
expandable
sleeve being fastened to the tubular part by means of a connection part,
- an annular barrier space between the tubular part and the expandable
sleeve,
and
5 - an aperture in the tubular part for letting fluid into the annular
barrier space to
expand the sleeve,
wherein annular barriers are arranged, separating the first reservoir zone and
the
second reservoir zone.
Furthermore, the expandable sleeve may be made of metal.
The present invention also relates to a well completion comprising the
production
system as described above and a well head.
The well completion may further comprise a control unit arranged in the well
head for adjusting the inflow devices.
In addition, the well completion may further comprise a key tool connected
with a
downhole tractor for adjusting the inflow devices.
Further, the present invention relates to a production method for production
of
hydrocarbons from a well, comprising the steps of:
- determining a first reservoir zone comprising at least a first fluid,
- determining a second reservoir zone comprising at least a second fluid,
- opening a first inflow device in the first zone to let the at least first
fluid into a
production casing at a first volume rate,
- opening a second inflow device in the second zone to let the at least
second
fluid into the production casing at a second volume rate,
- monitoring a production outcome of the well, and
- adjusting the first and second inflow devices based on the production
outcome
so that the first volume rate is equal to or higher than the second volume
rate or
so that the second volume rate is higher than the first volume rate.
In said method, the monitoring step may comprise one or more of the steps of:
- measuring a pressure at the top of the well,
- measuring a volume rate of the production outcome at the top of the well,
and/or
- measuring a water content of the production outcome at the top of the
well.
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Also, the step of adjusting the first and second inflow devices may further
comprise adjustment of at least one of the inflow devices based on the
measured
pressure, volume rate and/or water content at the top of the well.
Moreover, the step of step of adjusting the first and second inflow devices
may
be performed manually, e.g. by a key tool connected with a downhole tractor.
Additionally, the step of adjusting the first and second inflow devices
further may
be performed remotely from the top of the well.
Finally, the step of adjusting the first and second inflow devices further may
be
performed wirelessly.
Brief description of the drawings
The invention and its many advantages will be described in more detail below
with reference to the accompanying schematic drawings, which for the purpose
of
illustration show some non-limiting embodiments and in which
Fig. 1 shows a production system according to one embodiment of the invention,
Fig. 2 shows another embodiment of the production system having a plurality of
reservoir zones,
Fig. 3 shows a diagram of volume rate in relation to pressure,
Fig. 4 shows a cross-sectional view of an embodiment of an inflow device,
Fig. 5 shows a cross-sectional view of another embodiment of an inflow device,
Fig. 6 shows a cross-sectional view of an additional embodiment of an inflow
device,
Fig. 7 shows, in a partly cross-sectional view and partly in perspective, the
inflow
device of Fig. 4,
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Figs. 8a-8o show cross-sectional views of different positions of the inflow
device
of Figs. 4 and 7 in relation to the volume rate,
Fig. 9 shows a cross-sectional view of the inflow device of Fig. 6,
Fig. 10 shows, in a partly cross-sectional view and partly in perspective,
another
embodiment of the inflow device having an axially sliding inner sleeve, and
Fig. 11 shows a cross-sectional view of the inflow device of Fig. 10 along the
axial
extension.
All the figures are highly schematic and not necessarily to scale, and they
show
only those parts which are necessary in order to elucidate the invention,
other
parts being omitted or merely suggested.
Detailed description of the invention
Fig. 1 shows a production system 1 for producing hydrocarbons from a well 2.
The production system 1 comprises a production casing 3 extending along the
well 2. The production system 1 furthermore comprises a monitoring unit 4
adapted to measure a production outcome of the well 2. In this embodiment, the
monitoring unit is positioned at the top of the well 2, i.e. at the well head
5. The
monitoring unit may comprise a flow measuring device, a pressure sensor, a
water cut measuring device or a combination thereof.
The production system 1 also comprises a first reservoir zone 6 comprising at
least a first fluid 10, extending along and outside the production casing 3,
and a
second reservoir zone 7 comprising at least a second fluid 11, extending along
and outside the production casing. Furthermore, a first inflow device 8 is
arranged in the first reservoir zone 6, having a first inflow area and being
adapted to let the first fluid 10 into the production casing 3 at a first
volume rate
V1, and a second inflow device 9 is arranged in the second reservoir zone 7,
having a second inflow area and being adapted to let the second fluid 11 into
the
production casing 3 at a second volume rate V2. The first and second inflow
areas of the inflow devices 8, 9 are adjustable, whereby the first and second
inflow devices 8, 9 can be adjusted based on the production outcome so that
the
first volume rate V1 is equal to or higher than the second volume rate V2.
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Hereby, it is obtained that the production of hydrocarbons from the well 2 may
be optimised by adjusting the inflow volume rates of the inflow devices 8, 9
to
the instantaneous requirement based on either the volume rate of the
production
outcome, the pressure at the top of the well 2, the water content of the
production outcome, or a combination thereof. Thus, by means of the present
system, it is possible to create lift of the fluids in the well by adjusting
the inflow
volume rates of the fluids and thereby avoid using artificial lift or at least
substantially reduce the use of artificial lift.
In the event that the first fluid 10 comprises more water or gas, it may be
used
for driving the second and heavier fluid 11, and thus, artificial lift higher
up the
well may be avoided. Similarly, the second fluid may have a higher content of
water which is normally shut off by hindering its inflow into the casing,
however,
the second fluid may be useful for mixing with the first fluid to ease the
flow of
the well of the first fluid.
In the production system 1 shown in Fig. 1, the first and second reservoir
zones
6, 7 are adjacent zones, and they are separated from each other by expandable
annular barriers 12. In Fig. 1, the first fluid 10 in the first reservoir zone
6 is
essentially oil and the second fluid 11 in the second reservoir zone 7 is
essentially
water. The first and second reservoir zones 6, 7 each has a reservoir pressure
of
300 bar. The first inflow device 8 of the first reservoir zone 6 is adjusted
to let in
the first fluid 10, i.e. oil, so that there is a pressure of 200 bar in the
production
casing 3. Thereby, there is a pressure difference of 100 bar between the
reservoir and the casing. The second inflow device 9 of the second reservoir
zone
7 is adjusted to let in the second fluid 11, i.e. water, so that there is a
pressure
of 250 bar in the production casing 3, i.e. the 200 bar from the first zone
and 50
bar from the second zone. Thereby, a there is a pressure difference of 50 bar
between the reservoir at the second zone and the production casing. By letting
in
the second fluid 11, i.e. water, a higher water content is obtained in the
production outcome. However, at the same time, a higher volume rate of the
production outcome and enhanced lift to the well are achieved. In fact, the
energy in the reservoir is utilised for lifting the well instead of using
secondary
means, such as an artificial lift by means of gas, or adding chemicals, for
providing lift.
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In Fig. 2, the production system has five reservoir zones 6, 7, 13, 14, 15
mutually separated by expandable annular barriers 12. In Fig. 2, the first and
second reservoir zones 6, 7 are separated by another reservoir zone 14 having
a
third fluid 10b with a lower oil content than the first fluid 10. Below the
first zone
6 furthest away from the well head 5, there is another reservoir zone 13
having a
fourth fluid 10a which also has a lower oil content than the first fluid 10.
Furthermore, above the second zone 7, there is a fifth zone 15 having a fourth
fluid 11a with a lower water content than the second fluid 11. Furthermore,
one
or more of the additional inflow devices 16, 17, 18 arranged in the other
reservoir zones 13, 14, 15, respectively, may also be adjusted to let fluid at
certain volume rates into the production casing to enhance the lift in the
well and
provide an optimum production outcome. Thus, the production system 1 may
function in the same manner as described in relation to Fig. 1.
Fig. 3 shows a diagram disclosing different relationships between volume rate
of
the production outcome and pressure. As an example, the diagram has three
different curves 19, 20, 21 each representing varying volume rates at a
certain
pressure. In the example above disclosed in Fig. 1, the first inflow device is
positioned at a high volume rate at a pressure lower than that of the second
inflow device, and the fluid there-through would therefore follow curve 20.
The
second device is positioned at a lower volume rate but at a higher pressure,
and
the fluid there-through will therefore be positioned on curve 21 but not at a
volume rate as high as that of the fluid through the first inflow device. From
the
diagram, it is deducible that a high pressure and a high volume rate, cf.
curve
21, provide a high production outcome.
Fig. 4 shows a cross-sectional view of the inflow device 8 along an axial
extension
of the inflow device 8 being concentric with the axial extension of the
casing. In
this embodiment, the inflow device 8 comprises an outer sleeve 22 and an inner
sleeve 23, and the inner sleeve 23 may be movable in relation to the outer
sleeve
22. The cross-sectional view is taken along a row of inflow openings 24
arranged
in the extension of the inflow device 8. In this row, there are seven inflow
openings 24. The inflow area of the inflow device is inter alia constituted by
these
inflow openings 24 each having an opening area. If the inflow device 8 has
several rows of inflow openings, the total opening area of all these rows
provides
the total available inflow area of the inflow device. The inflow openings 24
are in
fluid connection with the inner opening 25 of the second inner sleeve 23 so
that
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fluid from the reservoir may flow in through the inflow device 8. In this
embodiment, the inner opening 25 is shown as a through-going groove extending
in the axial extension of the inflow device 8. The inner opening 25 has a
larger
extension than the inflow openings 24 to ensure that the inner opening 25,
when
5 being aligned with the inflow openings, does not prevent the fluid from
flowing. A
screen 26 or filter is arranged on the outside of the inflow openings.
Another embodiment of the inflow device 8 is shown in Fig. 5 in a cross-
sectional
view along an axial extension of the inflow device 8. The inflow device 8 also
10 comprises the outer sleeve 22 and the inner sleeve 23 which are movable
in
relation to each other. The inflow openings 24 are in fluid connection with
the
inner openings 25 of the second inner sleeve 23 to allow fluid from the
reservoir
to flow in through the inflow device 8. In this embodiment, the inner openings
25
are shown as seven through-going holes being aligned with the inflow openings
24 of the outer sleeve. The inner openings 25 have a larger extension than
each
of the inflow openings 24 so they do not prevent the fluid from flowing.
Again, a
screen 26 or filter is arranged on the outside of the inflow openings 24.
An additional embodiment of the inflow device 8 is shown in Fig. 6 in a cross-
sectional view along a row of inflow openings 24 arranged in the extension of
the
inflow device 8. The inflow openings 24 terminate in an axially extending
channel
27 arranged in the wall of the outer sleeve 22. The axial channel 27 abuts an
axial channel 55 arranged in the inner sleeve 23, whereby the inflow openings
24
are in fluid communication with the inner opening 25 via the two axial
channels
27, 55, respectively. Also, in this embodiment, a screen 26 or filter is
arranged
on the outside of the inflow openings 24. The embodiment of the inflow device
8
shown in Fig. 6 will be described further in connection with Fig. 9 below.
The inflow device 8 of Fig. 4 is shown in perspective in Fig. 7. The inflow
device 8
comprises the outer sleeve 22 and the inner sleeve 23, wherein the inner
sleeve
23 is movable in relation to the outer sleeve 22 by rotation. Four rows of
inflow
openings 24, 28, 29, 30 are arranged adjacent to each other and along the
axial
extension of the inflow device 8. The first row has seven inflow openings 24,
as
shown in the cross-sectional view in Fig. 4. The second row has six inflow
openings 28. The third row has four inflow openings 29, and the fourth row has
two inflow openings 30.The inflow openings 24, 28, 29, 30 of the four rows
constitute the inflow area of the inflow device 8.
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In other embodiments, the inflow device may have a different number of rows
and a different number of inflow openings in each row. Thus, the embodiment
shown in Fig. 7 is one configuration of the inflow device 8.
The inner sleeve 23 is shown in Fig. 7 with four inner openings 25 visible in
cross-section, and the openings 25 are each aligned with an inflow opening in
the
row of inflow openings 24 arranged in the outer sleeve 22. Also, the inflow
device
8 may have a different number of inner openings and different positions along
the periphery of the inner sleeve.
Figs. 8a to 8o show a sequence of different adjustments to different positions
of
the inflow device in relation to the desired inflow volume rate of the inflow
device
8.
In the same manner as described above, the inflow device 8 comprises an inner
sleeve 23 or tubular which is rotatable within the outer sleeve 22 or tubular.
The
inflow device 8 is shown in a cross-sectional view of a radial extension of
the
inflow device 8. The outer sleeve 22 has four rows of inflow openings, 24, 28,
29,
30. In the first row 24, there are seven inflow openings, as shown in Fig. 7,
in the
second row 28, there are six openings, in the third row 29, there are four
openings, and in the fourth row, there are two openings. In Fig. 8a, the inner
sleeve 23 has ten inner openings 25, 31, 32, 33, 34, 35, 36, 37, 38, 39 in the
form of grooves, the grooves are shown in Fig. 4, and the openings are
arranged
along the periphery of the inner sleeve 23. The inner openings 25, 31, 32, 33,
34, 35, 36, 37, 38, 39 are arranged with predetermined distances between them
so that each row of outer inflow openings 24 can optionally be opened or
closed
by rotating the inner sleeve 23, which will be further described below.
In Fig. 8a, the rows of inflow openings 24, 28, 29, 30 are all aligned with
the
inner openings 31, 32, 33, 34 of the inner sleeve 23. Thus, in Fig. 8a, all
inflow
openings 24, 28, 29, 30 of the inflow device 8 are open, whereby fluid may
flow
through all nineteen openings. This is the maximum flow capacity of the inflow
device 8.
In Fig. 8b, the inner sleeve 23 is rotated slightly to the right, whereby the
inner
opening 25 is aligned with the first row of inflow openings 24, the inner
opening
31 is aligned with the row of inflow openings 29, and the inner opening 32 is
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aligned with the row of inflow openings 30. Thus, by this adjustment of the
inflow
device 8, the rows of inflow openings 24, 29, 30 are open and the row of
inflow
openings 28 is closed, resulting in thirteen openings being open. By rotating
the
inner sleeve even further so that the inner opening 25 is aligned with the
third
row of inflow openings 29, four openings are open, and by rotating the inner
sleeve even further so that the inner opening 25 is aligned with the fourth
row of
inflow openings 30, two openings are open.
In Fig. 8c, the inner sleeve 23 is rotated slightly to the left, whereby the
inner
opening 31 is aligned with the row of inflow openings 28, the inner opening 32
is
aligned with the row of inflow openings 29, and the inner opening 33 is
aligned
with the row of inflow openings 30. Thus, by this adjustment of the inflow
device
8, the rows of inflow openings 28, 29, 30 are open and the row of inflow
openings 24 is closed, resulting in twelve openings being open.
In Fig. 8d, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 8c, whereby the inner opening 32 is aligned with the row of
inflow openings 24, the inner opening 33 is aligned with the row of inflow
openings 28, and the inner opening 34 is aligned with the row of inflow
openings
29. Thus, by this adjustment of the inflow device 8, the rows of inflow
openings
24, 28, 29 are open and the row of inflow openings 30 is closed, resulting in
seventeen openings being open.
In Fig. 8e, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 8d, whereby the inner opening 33 is aligned with the row of
inflow openings 24, the inner opening 34 is aligned with the row of inflow
openings 28, and the inner opening 35 is aligned with the row of inflow
openings
30. Thus, by this adjustment of the inflow device 8, the rows of inflow
openings
24, 28, 30 are open and the row of inflow openings 29 is closed, resulting in
fifteen openings being open.
In Fig. 8f, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 8e, whereby the inner opening 34 is aligned with the row of
inflow openings 24 and the inner opening 35 is aligned with the row of inflow
openings 29. Thus, by this adjustment of the inflow device 8, the rows of
inflow
openings 24, 29 are open and the rows of inflow openings 28, 30 are closed,
resulting in eleven openings being open.
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In Fig. 8g, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 8f, whereby the inner opening 35 is aligned with the row of
inflow openings 28. Thus, by this adjustment of the inflow device 8, the row
of
inflow openings 28 are open and the rows of inflow openings 24, 29, 30 are
closed, resulting in six openings being open.
In Fig. 8h, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 8g, whereby the inner opening 35 is aligned with the row of
inflow openings 24 and the inner opening 36 is aligned with the row of inflow
openings 30. Thus, by this adjustment of the inflow device 8, the rows of
inflow
openings 24, 30 are open and the rows of inflow openings 28, 29 are closed,
resulting in nine openings being open.
In Fig. 8i, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 8h, whereby the inner opening 36 is aligned with the row of
inflow openings 28 and the inner opening 37 is aligned with the row of inflow
openings 30. Thus, by this adjustment of the inflow device 8, the rows of
inflow
openings 28, 30 are open and the rows of inflow openings 24, 29 are closed,
resulting in eight openings being open.
In Fig. 8j, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 8i, whereby the inner opening 36 is aligned with the row of
inflow openings 24 and the inner opening 37 is aligned with the row of inflow
openings 29. Thus, by this adjustment of the inflow device 8, the rows of
inflow
openings 24, 29 are open and the rows of inflow openings 28, 30 are closed,
and
this adjustment thus results in the same position as in Fig. 8f.
In Fig. 8k, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 8j, whereby the inner opening 38 is aligned with the row of
inflow openings 29 and the inner opening 39 is aligned with the row of inflow
openings 30. Thus, by this adjustment of the inflow device 8, the rows of
inflow
openings 29, 30 are open and the rows of inflow openings 24, 28 are closed,
resulting in six openings being open.
In Fig. 81, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 8k, whereby the inner opening 38 is aligned with the row of
inflow openings 28 and the inner opening 39 is aligned with the row of inflow
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openings 29. Thus, by this adjustment of the inflow device 8, the rows of
inflow
openings 28, 29 are open and the rows of inflow openings 24, 30 are closed,
resulting in ten openings being open.
In Fig. 8m, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 81, whereby the inner opening 38 is aligned with the row of
inflow openings 24 and the inner opening 39 is aligned with the row of inflow
openings 28. Thus, in this adjustment of the inflow device 8, the rows of
inflow
openings 24, 28 are open and the rows of inflow openings 29, 30 are closed,
resulting in thirteen openings being open.
In Fig. 8n, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 8m, whereby the inner opening 39 is aligned with the row of
inflow openings 24. Thus, by this adjustment of the inflow device 8, the rows
of
inflow openings 24 are open and the rows of inflow openings 28, 29, 30 are
closed, resulting in seven openings being open.
In Fig. 8o, the inner sleeve 23 is rotated slightly to the left in relation to
the
adjustment of Fig. 8n, whereby all rows of inflow openings 24, 28, 29, 30 are
closed. Thus, by this adjustment, the inflow device 8 is closed.
The sequence of adjustments shown in Figs. 8a-8o shows different flow
capacities
of the inflow device 8, resulting in fourteen different volume rates. Even
though
some possible adjustments of the inflow device 8 are not shown in Figs. 8a-8o,
it
is evident for the skilled person that the configuration of the inflow device
8
makes it possible to open and close all rows of inflow openings independently
of
each other by rotating the inner sleeve into the intended position.
Fig. 9 shows a longitudinal cross-sectional view of another embodiment of an
inflow device 8. The inflow device 8 comprises a first sleeve or tubular 40
having
twelve inflow openings 24 in a first wall 41 and twelve first axial channels
27
extending in the first wall 41 from the inflow openings 24 to an outlet 53. By
axial channels is meant that the channels extend in an axial direction in
relation
to the inflow device 8.
The inflow device also comprises a second sleeve 42 or tubular having a first
end
43 near the outlet 53 and a second end 44 and, in this view, six inner
openings
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25. Even though the second sleeve 42 or tubular only shows six inner openings
25, the number of inner openings is actually the same as in the first sleeve
40 or
tubular, i.e. 12 inner openings.
5 Furthermore, the second sleeve 42 or tubular is rotatable within the
first sleeve
40 or tubular, and the second sleeve 42 has a second wall 45 having twelve
second axial channels (not shown) extending in the second wall 45 from the
first
end 43 to the inner opening 25. Thus, each inner opening 25 has its own second
axial channel.
The second sleeve 42 or tubular is arranged in an inner circumferential recess
46
in the first wall 41 of the first sleeve 40 or tubular, meaning that when the
second sleeve 42 or tubular is arranged in the recess, the second sleeve 42 or
tubular will not decrease the overall inner diameter of the inflow device and
thereby of the production casing.
The second sleeve 42 or tubular is rotatable in relation to the first sleeve
40 or
tubular at least between a first position, in which the first channel 27 and
second
channel (not shown) are aligned to allow fluid to flow from the reservoir into
the
production casing via the first end 43 of the second sleeve 42 or tubular, and
a
second position (the position shown in Fig. 9), in which the first channel 27
and
second channel (not shown) are not aligned, meaning that fluid is prevented
from
flowing into the production casing.
The inflow device 8 also comprises a first packer 47 which is arranged between
the first sleeve 40 or tubular and the first end 43 of the second sleeve 42 or
tubular. The packer 47 extends around the inner circumferential recess 46 and
has an inner diameter which is substantially the same as that of the second
sleeve or tubular. The packer 47 has a number of through-going packer channels
48 corresponding to the number of first axial channels, i.e. in this
embodiment
twelve, the packer channels 48 being aligned with the first axial channels 27.
The
packer is fixedly connected with the first sleeve or tubular so that the
packer
channels 48 are fluidly connected with first axial channels. The packer is
ring-
shaped, and the through-going packer channels 48 extend through the packer
along the axial extension of the first sleeve or tubular.
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The packer 47 is preferably made of ceramics, whereby it is possible to make
the
contact surfaces of the packer 47 smooth, which enhances the sealing
properties
of the packer 47, since the smooth contact surface may be pressed closer to
the
opposite surface which is the first end 43 of the second sleeve 42 or tubular.
However, in other embodiments, the packer may be made of metal, composites,
polymers or the like.
Furthermore, a second packer 49 is arranged between the first sleeve 40 or
tubular and the second end 44 of the second sleeve 42 or tubular. However, in
another embodiment, the second packer is omitted, whereby the second end 44
of the second sleeve 42 or tubular faces the first wall of the first sleeve 40
or
tubular.
In Fig. 9, a first spring element 50 is arranged between the first packer 47
and
the first sleeve 40 or tubular. The spring element 50 thus forces the first
packer
against the second sleeve 42 to provide a seal therebetween.
Furthermore, the second sleeve 42 or tubular may comprise at least one recess
51 accessible from within, the recess 51 being adapted to receive a key tool
(not
shown) for rotating the second sleeve 42 or tubular in relation to the first
sleeve
40 or tubular.
The adjustment of the inflow devices 8, 9 may be performed manually, e.g. by
inserting a downhole tool having a key tool into the production casing and
moving the downhole tool to the inflow device which needs to be adjusted. The
inflow devices 8, 9 may also be operated by a magnetic source.
The inflow device 8 of Fig. 7 has an inner sleeve 23 rotating in relation to
an
outer sleeve 22, and in Fig. 10, the inner sleeve 23 slides axially in
relation to the
outer sleeve 22. The inner sleeve 23 slides in a recess in the outer sleeve
22, as
shown in Fig. 11 where the inner sleeve covers three of the four rows shown in
Fig. 10, and thus, all the inflow openings 24 except two are covered. The
first
row comprises eight inflow openings 24, the second row comprises six inflow
openings 24, the third row comprises four inflow openings 24, and the fourth
row
comprises two inflow openings 24. By sliding the sleeve back and forth in the
recess along the inner surface of the outer sleeve, the number of inflow
openings
24 which the fluid may flow through may be varied in the same manner as in the
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embodiment of the inflow device 8 shown in Fig. 7. In other embodiments of an
inflow device having an axially slidable inner sleeve, the inflow device may
have a
different number of rows and a different number of inflow openings in each
row.
Thus, the embodiment shown in Figs. 9 and 10 is only one configuration of the
inflow device 8.
Fig. 1 shows the production casing comprising annular barriers, each annular
barrier being adapted for expansion in an annulus 52 between a production
casing and an inside wall 54 of a borehole 55 downhole. Each annular barrier
comprises a tubular part 57 for mounting as part of the production casing and
an
expandable sleeve 58 surrounding the tubular part. Each end 59, 60 of the
expandable sleeve is fastened to the tubular part by means of a connection
part
72. At least one end is slidably connected with the tubular part. The
expandable
sleeve surrounds the tubular part and defines an annular barrier space 73
between the tubular part and the expandable sleeve. The annular barrier
further
comprises an aperture 71 in the tubular part for letting fluid into the
annular
barrier space to expand the sleeve. The annular barriers are arranged
separating
the first reservoir zone 6 and the second reservoir zone 7 so that three
annular
barriers provide two reservoir zones. The expandable sleeve, the tubular part
and
the connection parts are made of metal.
In other embodiments, the inflow devices may be remotely adjustable, e.g. by
wireline or wireless control.
The inflow device 8 is adapted to be inserted and form part of the production
casing 3, thus forming a cased completion (not shown). Accordingly, the ends
of
the inflow device 8 are adapted to be connected with another casing element by
conventional connection means, for instance by means of a threaded connection.
In the embodiments described above, the outer openings are shown as openings
per se. However, the outer openings may comprise flow restrictors, throttles
or
valves, such as inflow control valves (not shown).
Even though the above-mentioned embodiments have been described primarily
in relation to rotatable movement of the inner sleeve in relation to the outer
sleeve, the inner sleeve may be slidably movable in relation to the outer
sleeve.
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By fluid or well fluid is meant any kind of fluid that may be present in oil
or gas
wells downhole, such as natural gas, oil, oil mud, crude oil, water, etc. By
gas is
meant any kind of gas composition present in a well, completion, or open hole,
and by oil is meant any kind of oil composition, such as crude oil, an oil-
containing fluid, etc. Gas, oil, and water fluids may thus all comprise other
elements or substances than gas, oil, and/or water, respectively.
By a casing is meant any kind of pipe, tubing, tubular, liner, string etc.
used
downhole in relation to oil or natural gas production.
In the event that the tools are not submergible all the way into the casing, a
downhole tractor can be used to push the tools all the way into position in
the
well. A downhole tractor is any kind of driving tool capable of pushing or
pulling
tools in a well downhole, such as a Well Tractor .
Although the invention has been described in the above in connection with
preferred embodiments of the invention, it will be evident for a person
skilled in
the art that several modifications are conceivable without departing from the
invention as defined by the following claims.
