U.S. patent application number 14/374902 was filed with the patent office on 2015-03-26 for device and method for obtaining carbonic substances from oil sands.
This patent application is currently assigned to SIEMENS AKTIENGESELLSCHAFT. The applicant listed for this patent is Siemens Aktiengesellschaft. Invention is credited to Olaf Schmidt, Matthias Schoneich, Simon Schulze, Michael Welch.
Application Number | 20150083412 14/374902 |
Document ID | / |
Family ID | 47520917 |
Filed Date | 2015-03-26 |
United States Patent
Application |
20150083412 |
Kind Code |
A1 |
Schmidt; Olaf ; et
al. |
March 26, 2015 |
DEVICE AND METHOD FOR OBTAINING CARBONIC SUBSTANCES FROM OIL
SANDS
Abstract
A device for obtaining carbonic substances, particularly
bitumen, from oil sands is provided. The device has at least one
steam generator, an injection pipeline and a production pipeline.
Steam can be introduced into the oil sand via the injection
pipeline, and the carbonic substance can be removed from the oil
sand via the production pipeline. At least one steam turbine is
arranged between the steam generator and the injection pipeline. A
method for obtaining carbonic substances, particularly bitumen,
from oil sands is also provided.
Inventors: |
Schmidt; Olaf; (Gorlitz,
DE) ; Schulze; Simon; (Herrnhut, DE) ;
Schoneich; Matthias; (Gorlitz, DE) ; Welch;
Michael; (Sleaford, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Siemens Aktiengesellschaft |
Munich |
|
DE |
|
|
Assignee: |
SIEMENS AKTIENGESELLSCHAFT
Munich
DE
|
Family ID: |
47520917 |
Appl. No.: |
14/374902 |
Filed: |
December 17, 2012 |
PCT Filed: |
December 17, 2012 |
PCT NO: |
PCT/EP2012/075687 |
371 Date: |
July 26, 2014 |
Current U.S.
Class: |
166/272.3 ;
166/52 |
Current CPC
Class: |
E21B 43/2406 20130101;
C10G 1/045 20130101 |
Class at
Publication: |
166/272.3 ;
166/52 |
International
Class: |
E21B 43/24 20060101
E21B043/24; C10G 1/04 20060101 C10G001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 4, 2012 |
DE |
10 2012 000 092.8 |
Claims
1. A device for extracting carbonaceous substances from oil sands,
comprising at least one steam generator, an injection pipeline and
a production pipeline, wherein steam can be introduced into the oil
sand via the injection pipeline and the carbonaceous substances can
be removed from the oil sand via the production pipeline, wherein
at least one steam turbine is arranged between the steam generator
and the injection pipeline.
2. The device as claimed in claim 1, wherein the steam production
is carried out by a heat exchanger, wherein hot exhaust gas of a
heat engine or a directly fired boiler are used for steam
production.
3. A method for extracting carbonaceous substances from oil sands
by a device as claimed in claim 1, comprising: producing steam in
the steam generator; feeding the steam to the steam turbine;
expanding the steam in the steam turbine to a steam pressure which
is lower than, or equal to, the rock pressure; introducing the
steam via the injection pipeline into the oil sand; heating the oil
sand by the steam and breaking down the long-chain hydrocarbons of
the carbonaceous substances; and removing the carbonaceous
substances via the production pipeline.
4. The device as claimed in claim 1, wherein the carbonaceous
substances comprise bitumen.
5. The device as claimed in claim 2, wherein the heat engine
comprises a gas turbine.
6. The method as claimed in claim 3, wherein the carbonaceous
substances comprise bitumen.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the U.S. National Stage of International
Application No. PCT/EP2012/075687 filed Dec. 17, 2012, and claims
the benefit thereof. The International Application claims the
benefit of German Application No. DE 10 2012 000 092.8 filed Feb.
24, 2012. All of the applications are incorporated by reference
herein in their entirety.
FIELD OF INVENTION
[0002] The invention relates to a device and also to a method for
extracting carbonaceous substances, especially bitumen, from oil
sands.
BACKGROUND OF INVENTION
[0003] Large portions of the worldwide oil reserves exist in the
form of oil sands. A mixture of rock, clay, sand, water and bitumen
or other heavy oils is understood by oil sand. Only bitumen, which
typically exists with a viscosity of API 5.degree. to 15.degree.
with respect to deposits, shall be mentioned in the following text
as being representative for heavy oils, extra-heavy oils or
generally long-chain hydrocarbons. By means of corresponding
process steps, bitumen can be converted into synthetic crude
oil.
[0004] Oil sand deposits are mined if they lie in strata of shallow
depth, preferably by open-cast mining. Oil sand deposits, however,
often lie in deeper strata which are not accessible to open-cast
mining or the mining of which would be uneconomical in open-cast
mining. Oil sand deposits are typically mined after depths of about
60 m by so-called in-situ processes since with these processes the
removal of the surface layer, which lies above the oil sand
deposit, is not necessary.
[0005] A common in-situ process is steam assisted gravity drainage
(SAGD). With the SAGD process, the bitumen, which is present in the
earth in a deposit, is heated by superheated steam. As a result of
the heat effect the long-chain hydrocarbons of the highly viscous
bitumen are broken down. This, and the heating of the oil sand,
lead to a reduction of the viscosity of the bitumen which as a
result becomes free-flowing and can be conventionally pumped out of
the deposit.
[0006] The known device for the SAGD process comprises at least one
injection pipeline for feeding the superheated steam into the
deposit and a production pipeline through which the fluid bitumen
can be transported out of the deposit to the local surface. The
injection pipeline and the production pipeline are laid inside the
deposit essentially parallel to each other and extending
horizontally one above the other. The injection pipeline and the
production pipeline usually have a distance of about 5 to 10 m from
each other in the vertical direction. In the horizontal direction,
the pipes extend inside the deposit by a length of between several
hundred meters and a few kilometers. The injection pipeline is
typically located above the production pipeline. As a result of the
heating and the reduction of the viscosity of the bitumen, the
bitumen flows downward on account of gravitational force and
therefore towards the production pipeline and can be simply pumped
out there and transported to the earth's surface. The transporting
can be achieved either by oil lift pumps or by introduction of an
overpressure in the deposit. The introduction of overpressure has
the significant disadvantage, however, that earth displacements on
the earth's surface (blow out) can occur in the surrounding area of
the deposit, especially when the stratum above the deposit is of
small thickness. For this reason, the steam pressure, before
introduction into the deposit, is usually reduced by a restrictor
or a throttle valve to a pressure which is lower than the rock
pressure in the region of the deposit. The throttle valve is
arranged between the steam generator and the injection pipeline in
this case. Since the steam pressure is reduced in the throttle
valve, without being utilized, the process is inefficient. A
further disadvantage of the SAGD process is the enormous energy
expenditure. For pumping out one barrel (159 l) of bitumen, about
20 m.sup.3 of natural gas and about 3,000 l of water are required
for steam production.
SUMMARY OF INVENTION
[0007] It is therefore an object of the present invention to
develop the known SAGD process in such a way that the efficiency of
the device is increased. At the same time, it is an object of the
present invention to demonstrate a corresponding method for
extracting carbonaceous substances.
[0008] The object is achieved with regard to a device and a method
by the features of the independent claims. Further advantages of
the invention are the subject of the dependent claims.
[0009] The device according to aspects of the invention for
extracting carbonaceous substances, especially bitumen, from oil
sands, has at least one steam generator, at least one injection
pipeline and at least one production pipeline--wherein via the
injection pipeline steam can be introduced into the oil sand and
via the production pipeline the carbonaceous substance can be
removed from the oil sand--is distinguished by at least one steam
turbine being arranged between the steam generator and the
injection pipeline. As a result of the arrangement of the steam
turbine between the steam generator and the injection pipeline the
pressure reduction, which is usually carried out via the throttle
valve without being utilized, can be used for energy recovery. To
this end, the steam turbine is preferably connected to a generator
for current generation. The generated current can then be utilized
directly at site for crude oil production or be fed into an
electricity network. The steam, which is directed from the steam
generator to the steam turbine, is expanded in this case inside the
steam turbine to a pressure which is equal to, or lower than, the
rock pressure in the region of the deposit. This steam is then
directed into the deposit via the injection pipelines.
[0010] An advantageous embodiment of the invention provides that
the steam production carried out by a heat exchanger, wherein hot
exhaust gas of a heat engine, especially a gas turbine, is used for
steam production. By using a heat engine, especially a gas turbine,
the heating of the water and the subsequent evaporation can be
carried out in a particularly efficient manner. The gas turbine in
this case is connected to a second generator for current
generation. The exhaust gas of the gas turbine is used for the
heating and evaporating of the water. The heat energy of the
exhaust gas is preferably realized by a heat exchanger in which the
gas flow is conducted in counterflow to the water/steam. The
current which is generated in the generator can in turn be used
directly at site for processing the bitumen to form crude oil, or
can be fed into an electricity network. The steam production can
also be carried out by direct firing of the boiler.
[0011] The method according to aspects of the invention for
extracting carbonaceous substances, especially bitumen, from oil
sands by a device as claimed, includes the following method steps:
-Producing steam in the steam generator; -Feeding the steam to the
steam turbine; -Expanding the steam in the steam turbine to a steam
pressure which is lower than, or equal to, that of the rock
pressure in the region of the deposit of bitumen; -Introducing the
steam via the injection pipeline into the oil sand; -Heating the
oil sand by the steam and breaking down the long-chain hydrocarbons
of the carbonaceous substances; -Removing the carbonaceous
substances (bitumen) via the production pipeline.
[0012] The bitumen which is removed can then be processed at the
earth's surface by suitable measures to form crude oil.
[0013] By expanding the steam in the steam turbine to a steam
pressure which is lower than, or equal to, the rock pressure in the
region of the deposit, the energy of the steam, which previously
was discharged by the throttle valve into the environment without
being utilized, can be utilized for energy recovery, especially for
generating electric current by connecting the steam turbine to a
generator. By utilizing the steam pressure for generating electric
current the efficiency of the method is improved.
[0014] Further advantages of the invention, which can be applied
individually or in combination with each other, are explained below
based on an exemplary embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 shows in this case a device according to the
invention for extracting carbonaceous substances, especially
bitumen, from oil sands. The representation is a simplified and
schematic representation in which only the components which are
essential for the invention are shown.
DETAILED DESCRIPTION OF INVENTION
[0016] FIG. 1 shows an exemplary embodiment of a device according
to aspects of the invention for extracting carbonaceous substances,
especially bitumen, from oil sands. The oil sands are located in a
deposit 7 in the earth 8. If the rock layer above the deposit 7 is
not excessively large, the mining of the oil sand is carried out by
open-cast mining. After a depth of about 60 m, open-cast mining is
uneconomical, however, as already described, so that the in-situ
process which is described in the description introduction is then
used.
[0017] The device according to aspects of the invention for such a
method has at least one steam generator 1 and at least one
injection pipeline 2 and at least one production pipeline 3. The
injection pipeline 2 and the production pipeline 3 usually extend
horizontally inside the deposit 7. The injection pipeline 2 and the
production pipeline 3 in this case extend parallel to each other
and typically at a distance of about 5 to 10 m from each other. In
the horizontal direction, the pipes extend inside the deposit 7
over a length of between several hundred meters and a few
kilometers.
[0018] Before the bitumen can be extracted from the deposit, this
first of all has to be heated in order to reduce the viscosity of
the bitumen which is present in the oil sand or in the oil rock. As
a result of the heating, a break down of the long-chain
hydrocarbons of the highly viscous bitumen occurs, as a result of
which the viscosity reduces and the bitumen becomes free-flowing.
The heating of the deposit 7 is carried out by introduction of the
steam, which is produced in the steam generator 1, via the
injection pipeline 2. The free-flowing bitumen sinks downward on
account of gravitational force and can then be transported to the
surface as bitumen-water emulsion. For the transporting, simple oil
lift pumps are suitable. The bitumen-water emulsion can then be
processed in a corresponding processing plant to form crude oil.
The water of the water-oil emulsion is preferably recovered in the
process and fed again to the steam generator 1 via a corresponding
return line 10. The steam which is introduced into the deposit 7
via the injection pipeline 2 has to have a pressure which lies
below the rock pressure since otherwise earth displacements on the
surface (blow out) can occur. This occurs especially when the earth
above the deposit 7 is of small thickness. Since the pressure of
the steam downstream of the steam generator 1 is excessively high,
the steam first of all has to be reduced to the corresponding rock
pressure. To this end, a steam turbine 5 is arranged between the
steam generator 1 and the injection pipeline 2. The steam turbine 5
is connected to a generator G2 which serves for current generation.
The generated current can be used directly for the plant or be fed
into an electricity network. The steam turbine 5 is designed and/or
controlled in such a way that the steam, which is directed from the
steam generator 1 into the turbine 5, is only expanded to such a
degree that in the main it corresponds to the rock pressure inside
the deposit. By using the steam turbine 5 for pressure reduction of
the steam, energy recovery and therefore a considerably more
efficient operation are made possible compared with the previously
used throttle valves or restrictors.
[0019] The heat energy for the steam generator 1 is provided by the
exhaust gas of a gas turbine 6. The gas turbine 6 is connected to a
further generator 1 for current generation. The generated current
can in turn be used directly for the electric consumers of the
plant or be fed into an electricity network. Since the production
sites for oil sand frequently lie in regions which are not
accessible to a current supply, the current is usually used
directly for the plant, however. The heat energy of the exhaust gas
is yielded to the water or to the steam in the steam generator 1 by
a heat exchanger. In this case, the hot exhaust gas preferably
flows in counterflow to the water/steam. Alternatively, the steam
production can also be carried out by direct firing of the
boiler.
[0020] The method for extracting bitumen from oil sands by the
described device is briefly explained in the following text. In the
method, steam is first of all produced in the steam generator 1. To
this end, the heat energy of the exhaust gas of the steam turbine 6
is fed via a heat exchanger to the steam generator 1. In the steam
generator 1, the water is evaporated and the hot steam is first of
all fed to the steam turbine 5. A cyclone separator or the like is
advantageously incorporated upstream of the steam turbine, as a
result of which the water and impurities are separated from the
steam. As a result of this, the steam is dry saturated and
superheated. In the steam turbine 5, the steam pressure is
expanded, wherein the steam turbine 5 generates electric current
via a generator G2. The expanded steam, which has a steam pressure
which for example has the rock pressure in the deposit 7, is
introduced into the deposit 7 via the injection pipeline 2. The hot
steam in this case brings about a breakdown of the long-chain
hydrocarbons of the highly viscous bitumen in the oil sand. A
bitumen-water emulsion, which trickles downward on account of
gravitational force, is created in the process. The bitumen-water
emulsion can then be transported via the production pipeline 3 to
the earth's surface. To this end, an oil lift pump, which is not
shown in FIG. 1, is used. The bitumen-water emulsion from there
makes its way to a processing plant 9. In this, the bitumen is
separated from the water on the one hand and then the bitumen is
further processed to form crude oil. The water is fed back to the
evaporator 1 via a corresponding line 10 and can be evaporated
again there.
[0021] The device according to aspects of the invention and the
method according to aspects of the invention for extracting
carbonaceous substances, especially bitumen, from oil sand are
distinguished by surplus pressure energy of the steam being
expanded in a steam turbine downstream of the steam generator and
by the steam turbine generating additional electric energy via a
generator which can especially be utilized for the device. As a
result of this, an efficiency increase and therefore a more
economical operation of the device are made possible.
* * * * *