U.S. patent application number 14/234562 was filed with the patent office on 2014-06-19 for steam generation.
This patent application is currently assigned to TOTAL S.A.. The applicant listed for this patent is Bernard Corre. Invention is credited to Bernard Corre.
Application Number | 20140166301 14/234562 |
Document ID | / |
Family ID | 46508370 |
Filed Date | 2014-06-19 |
United States Patent
Application |
20140166301 |
Kind Code |
A1 |
Corre; Bernard |
June 19, 2014 |
STEAM GENERATION
Abstract
A steam generation device and a method for generating steam
using the device are disclosed. The device includes a fluid
circulation pipe containing electrically and thermally conductive
material, and at least one inductive cable made from an
electrically conductive material wound around the pipe. The device
and method allow for improved steam generation.
Inventors: |
Corre; Bernard; (Pau,
FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Corre; Bernard |
Pau |
|
FR |
|
|
Assignee: |
TOTAL S.A.
Courbevoie
FR
|
Family ID: |
46508370 |
Appl. No.: |
14/234562 |
Filed: |
July 17, 2012 |
PCT Filed: |
July 17, 2012 |
PCT NO: |
PCT/EP2012/063952 |
371 Date: |
January 23, 2014 |
Current U.S.
Class: |
166/372 ;
219/643; 392/397 |
Current CPC
Class: |
E21B 43/2406 20130101;
F22B 1/282 20130101; E21B 43/2401 20130101; E21B 36/04 20130101;
F22B 37/103 20130101; F22B 1/281 20130101; H05B 6/108 20130101;
H05B 6/107 20130101 |
Class at
Publication: |
166/372 ;
219/643; 392/397 |
International
Class: |
F22B 1/28 20060101
F22B001/28; E21B 43/24 20060101 E21B043/24 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 25, 2011 |
FR |
1156726 |
Claims
1. A steam generating device for producing hydrocarbons, wherein
the device comprises: a fluid circulation pipe containing
electrically and thermally conductive material; and at least one
inductive cable made from an electrically conductive material wound
around the pipe.
2. The device according to claim 1, wherein the pipe has at least
one protuberance on an inner wall.
3. The device according to claim 2, wherein the pipe is cylindrical
and the protuberance is a helical ramp along the pipe.
4. The device according to claim 3, wherein the ramp is
continuous.
5. The device according to claim 1, wherein the device also
comprises a shell made from a ferromagnetic material around the
inductive cable.
6. The device according to claim 1, wherein the inductive cable
forms a solenoid.
7. The device according to claim 1, wherein the inductive cable is
hollow.
8. The device according to claim 1, wherein the pipe has a diameter
smaller than 20 cm.
9. The device according to claim 1, wherein the pipe has a length
smaller than 30 m.
10. The device according to claim 1, wherein the device also
comprises an electricity source supplying the cable.
11. The device according to claim 10, wherein the electricity
source delivers a current with an intensity greater than 500 A.
12. The device according to claim 1, wherein the device comprises
several water circulation pipes connected to one another.
13. A hydrocarbon production facility, comprising a steam
generating device operably producing hydrocarbons, wherein the
device comprises: a fluid circulation pipe containing electrically
and thermally conductive material; and at least one inductive cable
made from an electrically conductive material wound around the
pipe.
14. A hydrocarbon production method comprising: generating steam;
producing hydrocarbons with a steam generator, wherein the steam
generator comprises a fluid circulation pipe containing
electrically and thermally conductive material, and at least one
inductive cable made from an electrically conductive material wound
around the pipe; and circulating water in the pipe, and, at the
same time, supplying electricity to the cable.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a National Phase Entry of International
Application No. PCT/EP2012/063952, filed on Jul. 17, 2012, which
claims priority to French Patent Application Serial No. 1156726,
filed on Jul. 25, 2011, both of which are incorporated by reference
herein.
FIELD OF THE INVENTION
[0002] The present invention relates to steam generation, and more
particularly a device and a method for generating steam.
BACKGROUND
[0003] Steam generation is applicable in multiple fields, in
particular in the context of hydrocarbon production. For example,
the production of viscous oils, whether heavy or not, may require
fluidization of the oils (i.e. a reduction in the viscosity of the
oils) before they are extracted. This fluidization is even more
useful for heavy oils contained in sands, for example asphaltic
sands (e.g. like those in Canada or Venezuela). However, the
viscosity reduction of an oil is generally obtained by providing
heat energy. To that end, steam is often injected into the
reservoir.
[0004] Various steam injection techniques are used at this time
(e.g. CSS, steam drive, or SAGD). Steam generation is generally
done on the surface using a dedicated plant or different types of
generators. The steam is then conveyed into the reservoir using a
pipe partially located on the surface. Such steam generators
therefore have a footprint that makes the placement of a production
facility complex. It is for example difficult to consider adding
steam generators on small offshore platforms. Furthermore, surface
steam generation involves heat losses in the parts of the pipe on
the surface and in the well. Heat losses in the well can heat the
land adjacent to the well, and not only the reservoir (which is
generally at the bottom of the well). These heat losses are
particularly problematic if the well passes through the permafrost.
These heat losses reduce the quality of the steam. These heat
losses generally require that the depth of the targets be reduced.
The surface generator is generally a fossil energy generator (gas,
or recycling part of the oil produced). The aforementioned losses
decrease the efficiency of steam injection facilities.
[0005] Document WO 1988/000276 A1 discloses a heat generator for
oil wells comprising an elongate chamber in which a pair of
non-concentric electrodes is located at least partially submerged
in water. During operation, the electrodes are supplied with energy
and heat the water. However, the generator of this document is not
fully satisfactory in light of the aforementioned drawbacks.
[0006] Furthermore, certain documents, such as document EP 0 387
125 and document GB 427838, teach the heating of a liquid passing
through a pipe that forms the secondary circuit of an electric
transformer. These transformers operate using a closed
ferromagnetic core. For example, the primary circuit (supplied with
electricity) winds around a first branch and the secondary circuit
(formed by the pipe) winds around a branch parallel to the first
branch. Consequently, two of the three dimensions (height, width
and length) of the devices of these documents are too large to be
inserted into a well for a given flow rate of steam to be produced.
They are therefore not ideally suited to an oil application.
[0007] The aim of the present invention is to provide an improved
device and method for generating steam, at least partially
overcoming the aforementioned drawbacks.
SUMMARY
[0008] To that end, the present invention proposes a steam
generation device. The device comprises a fluid circulation pipe
containing electrically and thermally conductive material, and at
least one inductive cable made from an electrically conductive
material wound around the pipe. The invention also proposes a
method for generating steam using the steam generating device. The
method comprises circulating water in the pipe and, simultaneously,
electrically supplying the inductive cable. The invention also
proposes a hydrocarbon production method, in which the method
comprises generating steam according to the steam generation
method. The invention also proposes a hydrocarbon production
facility, in which the facility comprises the steam generating
device.
[0009] According to preferred embodiments, the invention comprises
one or more of the following features: [0010] the pipe has at least
one protuberance on an inner wall; [0011] the pipe is cylindrical;
[0012] the protuberance is a helical ramp along the pipe; [0013]
the ramp is continuous or broken; [0014] the device also comprises
a shell made from a ferromagnetic material around the inductive
cable; [0015] the inductive cable forms a solenoid; [0016] the
inductive cable is hollow; [0017] the pipe has a diameter smaller
than 20 cm, preferably smaller than 15 cm; [0018] the pipe has a
length smaller than 30 m, preferably 20 m, and/or larger than 5 m,
preferably 10 m; [0019] the device also comprises an electricity
source supplying the cable; [0020] the electricity source delivers
a current with an intensity greater than 500 A, preferably greater
than 900 A; and [0021] the device comprises several water
circulation pipes connected to one another.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Other features and advantages of the invention will appear
upon reading the following description of one preferred embodiment
of the invention, provided as an example and in reference to the
appended drawings.
[0023] FIG. 1 shows an example of the steam generation method;
[0024] FIGS. 2 and 3 show an example of a steam generating
device;
[0025] FIG. 4 shows an example of a susceptor; and
[0026] FIG. 5 shows an example of magnetic field lines in a steam
generating device.
DETAILED DESCRIPTION
[0027] A steam generating device is proposed. The device comprises
a fluid circulation pipe containing electrically and thermally
conductive material, and at least one inductive cable (one or more
cables) made from an electrically conductive material wound around
the pipe. Such a device improves the steam generation.
[0028] The water circulation pipe allows water to circulate from an
inlet of the pipe toward an outlet of the pipe. The pipe contains
conductive material, for example steel. It may be completely or
partially made from said electrically (i.e. capable of conducting
electricity) and thermally (i.e. capable of effectively conducting
heat) conductive material. The inductive cable is made from
electrically conductive material and is therefore an electrical
cable, for example made from copper. The inductive cable may assume
any form. The inductive cable may for example have a square
section. The section of the cable may be larger than 9 mm.sup.2,
preferably 36 mm.sup.2, and/or less than 144 mm.sup.2, preferably
64 mm.sup.2.
[0029] Because the inductive cable winds, it has turns. The
inductive cable can therefore induce a high magnetic field inside
said turns if the inductive cable is supplied with electricity. The
conductive material of the pipe makes it possible to generate
Foucault currents if it is subjected to such a magnetic field.
Thus, subjected to such a magnetic field, the Foucault currents
heat the pipe by Joule effect and transfer the heat energy to a
fluid that may be present in the pipe, so as to potentially make
steam. The inductive cable winds around the pipe and therefore
allows the appearance of such a magnetic field where the inductive
cable winds around the pipe. One advantage of such an arrangement
is also the length of the pipe useful for such heating. In fact,
the heating occurs over the entire length on which the inductive
cable is wound around the pipe and occurs gradually while the fluid
circulates in the pipe. Such a device allows a good efficiency
(output), and therefore produces high-quality water vapor (if the
fluid is water). The steam quality is the ratio between the amount
of water in saturated steam form and the total quantity of water
(i.e. liquid+saturated steam). Furthermore, the longitudinal shape
of the device makes it particularly suitable for an oil
application. Indeed, the device is easy to insert into a well. Such
a device also makes it possible to have a rectilinear flux, as well
as better preservation of the input pressure.
[0030] The inductive cable can form a solenoid. In particular, the
inductive cable can form a coil with a length at least two times
longer than the diameter of the coil. This ensures a powerful
magnetic field at the pipe, and therefore good Joule effect
heating. Preferably, the inductive cable winds around the pipe over
a length greater than 50 times the diameter of the pipe, preferably
greater than 200 times the diameter of the pipe, which ensures
heating over a large length of the pipe.
[0031] The device can comprise a shell made from a ferromagnetic
material around the inductive cable. The shell channels the
magnetic field so as to optimize heating. Furthermore, if the
device is inserted into a casing (i.e. a metal tube cemented to the
wall of the well), the shell protects the casing from the magnetic
flux. The ferromagnetic material of the shell may be soft iron or
any other material having the characteristics of a soft
ferromagnetic material.
[0032] The pipe can have at least one protuberance on an inner
wall. The term "susceptor" will hereafter be used to designate that
protuberance, or all of the protuberances if applicable. The
susceptor may be a part of the pipe protruding toward the inside of
the pipe. The susceptor increases the inner surface of the pipe and
generates hot spots (which may exceed 300.degree. C., for example
350 to 400.degree. C.). The susceptor therefore improves the
heating of a fluid in the pipe. The susceptor also generates
turbulence in the circulation of such a fluid. This turbulence
forms currents that homogenize the fluid and thereby distribute the
heat so as to improve heating. The susceptor also causes pressure
losses (i.e. local losses of pressure) that favor steam
generation.
[0033] Different forms of susceptors may be made. For better
heating, the susceptor may form a helical ramp along the pipe that
may be cylindrical. The ramp may be continuous or broken. In the
event the ramp is broken, the susceptor therefore comprises several
protuberances positioned on a helical line virtually drawn inside
the pipe.
[0034] The inductive cable can be hollow. In that case, the
inductive cable comprises an empty passage at the center thereof.
This passage allows a cooling liquid to circulate inside the
inductive cable, for example water, which makes it possible to
avoid damaging the inductive cable. Such cooling of the inductive
cable may also serve to preheat the water to be vaporized. For
example, the passage in the inductive cable may be connected to the
pipe upstream of the pipe. In this way, in any steam generating
method using the device, the water can circulate in the inductive
cable before arriving, already preheated, in the pipe, where the
water can evaporate more easily.
[0035] The pipe may have an (outer) diameter smaller than 20 cm,
preferably smaller than 15 cm. The casings of the borehole have a
diameter of approximately 30 cm. The inner diameter of the pipe may
be less than 16 cm, preferably less than 10 cm. In this way, the
sizing of the pipe makes it possible to provide space to wind the
inductive cable around the pipe. The device is consequently
well-suited to the borehole diameters typically used, i.e. between
23 cm and 25 cm.
[0036] The pipe may have a length smaller than 13 m, preferably 10
m, and/or greater than 5 m, preferably 8 m, preferably equal to at
least approximately 9 m. These dimensions present a good compromise
between ease of installation and useful length exploited. In fact,
the longer the pipe, the more heating may be done over a large
length. However, the length is limited for better adaptation to
standard borehole rigs (i.e. borehole facilities).
[0037] The device may also comprise an electricity source supplying
the inductive cable. The electricity source may be on the surface
and transmit electrical energy to the inductive cable(s) winding
around the pipe(s) (at the reservoir in the well) by means of one
or more transmission cables. Such a generator may not be based on
fossil energies. It cannot generate greenhouse gases, in any case
in an excessively localized manner. Such a generator is therefore
cleaner, and has a good efficiency, since the electricity is easily
transportable at low frequencies, with lower losses during
transmission. Such a device improves the output, since there are no
longer any heat losses. In fact, the steam is generated directly in
the well at a distance closer to the formation than the wellhead
and not conveyed from the surface.
[0038] The electricity supplied to the cable may be a current
greater than 500 A, preferably greater than 900 A. For a lower loss
with such intensities, the device preferably comprises several
transmission cables. The electricity source is then adapted to
provide the appropriate voltage. The appropriate voltage may be
comprised between 5 and 10 kV.
[0039] The pipe may also make up a partially closed enclosure, the
pressure inside the tube being little influenced by the pressure of
the formation. This makes it possible to control the pressure to
which the fluid is subjected when it is heated. In this way, it is
possible to know the characteristics of the generated steam (if the
fluid is water) easily and to better control the steam generation
over time. The invention is sized as a function of the
characteristics of the formation; in particular, the steam pressure
delivered by the system according to the invention is greater than
the pressure of the formation to be exploited.
[0040] The device may comprise several water circulation pipes
connected to one another. The pipes may be connected in fluid
communication using mechanical connections for water circulation
inside all of the pipes thereafter. The cables winding around the
pipes are connected by electrical connections. It is for example
possible to connect three pipes to one another.
[0041] The device may be comprised in a hydrocarbon production
facility. The device may in particular be located in the well, so
that the steam is generated in the well directly at the reservoir.
Such a facility is therefore compact and allows exploitation of all
highly viscous hydrocarbon reservoirs, owing to the quality of the
generated steam, the controlling of the characteristics of the
generated steam, and the compactness of the facility, which in
particular allows offshore exploitation.
[0042] The production facility may comprise a borehole rig. The
placement of the device may then comprise: [0043] positioning a
pipe, with winding of at least one electrical cable around it, in
the rig, [0044] lowering the pipe into the well, the top of the
pipe remaining accessible from the rig, [0045] positioning a new
pipe in the rig, [0046] assembling the new pipe, with winding of at
least one electrical cable around it, with the previous pipe,
including the electrical connection of the cable of the new pipe to
the cable of the preceding pipe, the above steps being repeated,
for example until three pipes are connected.
[0047] In reference to FIG. 1, the device may be used in a steam
generating method that comprises the circulation (S1) of water in
the pipe, and, at the same time, the supply (S2) of electricity to
the cable. The electrical power of the cable induces the magnetic
field, the heating of the conductive material of the pipe, and the
heating to the point of vaporization of water circulating in the
pipe at the same time as the electricity supply. Such a device
therefore allows vaporization of water with a good efficiency and
good quality of the generated steam. As mentioned above, the water
may be heated beforehand. To that end, the method may comprise
prior circulation of the water in the cable, to cool it.
[0048] This method may be comprised in a hydrocarbon production
method. The steam may be generated directly at the reservoir and
may therefore be directly injected into the reservoir without heat
losses. The hydrocarbons can then be extracted more easily, which
is particularly advantageous in the case of viscous or heavy
oils.
[0049] In such a method, the steam may be generated at a flow rate
of 100 to 300 tons per day, preferably 200 tons per day. The
hydrocarbon production method may be done by H&P (Huff &
Puff, i.e. the method comprises the cyclic injection of steam in
the reservoir) or by Steam Drive (i.e. the method comprises
continuously sweeping the reservoir with steam). The same device
can provide these different injection forms. The device is
therefore versatile.
[0050] Examples of the device will now be described in reference to
FIGS. 2 to 5. FIG. 2 shows one example of the steam generating
device 10 in longitudinal cross-section. In FIG. 2, the device 10
is shown with its fluid circulation pipe 12 containing electrically
and thermally conductive material and the inductive cable 14 made
from electrically conductive material that is wound around the pipe
12. FIG. 3 shows a section of the device 10 of FIG. 2, transversely
relative to the longitudinal central axis 22 of the device 10, and
comprising the portion 29 of the pipe 12 around which the inductive
cable 14 winds.
[0051] As shown in the figures, liquid water 16 can penetrate the
pipe 12, circulate therein, and leave it in steam form (potentially
containing liquid as a function of the quality attained). In fact,
the cable 14 is electrically supplied with voltage from the
electricity source 19 and heats the pipe 12 owing to the magnetic
field induced over the entire length of the winding. In this
example, the device 10 comprises the transmission cables 24, which
convey electricity to the cable 14, and the susceptor 20 on the
inner wall of the pipe 12 (protuberances oriented toward the inside
of the pipe 12, therefore toward the axis 22). A good thermal
efficiency is therefore obtained. This results in vaporizing the
water 16. The figures show that the device 10 is compact and in
longitudinal form. The length of the device 10 is at least twice as
large as its width. The device 10, which is not very bulky, is thus
suitable for insertion into a borehole well.
[0052] Furthermore, the device may comprise several (three) pipes
connected to one another by connections, to form a total length 29
for example of 27 m around which the cable 14 is wound, each pipe
12 around which the cable 14 is wound having a length of 9 m. The
device 10 is also shown when it is installed inside a well. The
figures in particular show the casing 23 of the well surrounded by
cement 13. At the cable 14, the geological ground comprises
hydrocarbons and thus constitutes a reservoir 25. Locating the
pipes 12 around which a cable 14 is wound at the reservoir thereby
makes it possible to avoid heat losses. In this way, the portion 26
of the subsoil closest to the surface 15, which does not contain
hydrocarbons, is not needlessly heated. The figure also shows the
shell 27 that protects the casing 23 from excessive
temperatures.
[0053] FIG. 4 shows a susceptor 50 in the form of a helical ramp in
the pipe 12 which can be used in the device 10 of FIGS. 2 and 3.
FIG. 4 showing a transverse section of the pipe 12, the susceptor
50 assumes the form, in the plane of the section, of regularly
spaced protuberances. The susceptor 50 can be made from a thermally
and electrically conductive material, and thereby increase the heat
exchange surface with the fluid, as shown in the figure.
[0054] FIG. 5 diagrammatically shows one example of magnetic field
lines 40 in one example of a steam generating device 10. The
magnetic field lines 40 were obtained using finite element
calculation software. The device is partially shown in longitudinal
cross-section. Only half of the device is shown. The device of this
example is according to FIG. 2 or 3 and in particular comprises the
shell 27 around the cable 14. The figure shows that the shell 27
makes it possible to concentrate the magnetic field at the pipe 12
and protect the casing 23, which is slightly exposed to the
magnetic field. In this way, the device 10 allows good Joule effect
heating of the pipe 12 with less damage to the casing 23. Of
course, the present invention is not limited to the examples
described and illustrated, but is open to various alternatives
accessible to those skilled in the art.
* * * * *