U.S. patent application number 11/678614 was filed with the patent office on 2007-09-06 for in-situ extraction of hydrocarbons from oll sands.
This patent application is currently assigned to HCE, LLC. Invention is credited to Udo von Wimmersperg.
Application Number | 20070204994 11/678614 |
Document ID | / |
Family ID | 38470501 |
Filed Date | 2007-09-06 |
United States Patent
Application |
20070204994 |
Kind Code |
A1 |
von Wimmersperg; Udo |
September 6, 2007 |
IN-SITU EXTRACTION OF HYDROCARBONS FROM OlL SANDS
Abstract
A device and method of using the device enable the in-situ
extraction of hydrocarbons from oil sands and other hydrocarbon
resources. The preferred embodiment of the device includes at least
two electrodes of tubular form wherein said electrodes are porous
and capable of being inserted into the ground; a source of
electrical current to apply to the electrodes; and a means for
extracting the hydrocarbons from the tubular electrodes. In the
preferred embodiment of the method of the invention, the electrodes
are inserted into the oil deposit and connected to an electrical
potential difference sufficient to drive an electric current
between in-ground electrodes. Current is then flowed between the
electrodes. The pressure gradient, resulting from heating the
oil-bearing fluid, drives product into the tubular electrodes where
it is removed.
Inventors: |
von Wimmersperg; Udo;
(Bellport, NY) |
Correspondence
Address: |
LOUIS VENTRE, JR
2483 OAKTON HILLS DRIVE
OAKTON
VA
22124-1530
US
|
Assignee: |
HCE, LLC
Oakton
VA
|
Family ID: |
38470501 |
Appl. No.: |
11/678614 |
Filed: |
February 25, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60767120 |
Mar 4, 2006 |
|
|
|
Current U.S.
Class: |
166/302 ;
166/272.1; 166/65.1 |
Current CPC
Class: |
E21B 43/2401
20130101 |
Class at
Publication: |
166/302 ;
166/272.1; 166/65.1 |
International
Class: |
E21B 36/00 20060101
E21B036/00 |
Claims
1. A device for the in-situ extraction of hydrocarbons comprising,
a plurality of electrodes in tubular form wherein said electrodes
are porous and capable of being inserted into the ground; a source
of electrical current to apply to the electrodes; and, a means for
extracting the hydrocarbons from the tubular electrodes.
2. The device of claim 1 wherein the electrodes are steel tubes of
six-inch diameter with a thickness of copper on the inner wall.
3. The device of claim 1 further comprising electrically insulating
sleeves installed over the electrodes where the electrodes are in
contact with overburden.
4. The device of claim 1 further comprising an electrode at the end
of a casing wherein the electrode is electrically insulated from
the casing.
5. The device of claim 1 wherein the source of electrical current
is capable of providing a pulsed current.
6. The device of claim 5 wherein the pulsed current is at least
about 1,000 amps current over a period of about 20 seconds to 2
minutes.
7. The device of claim 5 wherein said source of electrical current
is a motor and flywheel configured such that after the flywheel
reaches a rotation corresponding to the energy desired, that
rotational energy is discharged by turning a generator, which
creates the desired pulse of electrical current.
8. The device of claim 1 wherein the means for extracting is a
valved pipeline.
9. The device of claim 1 wherein the means for extracting is a
pump.
10. A method of using the device of claim 1 comprising the steps
of, inserting the electrodes into a hydrocarbons deposit in the
ground; running a current between the electrodes of sufficient
magnitude to heat the ground between the electrodes; and,
extracting the hydrocarbons from the electrodes.
11. The method of using of claim 8 further comprising the step of
injecting an electrolyte into the deposit through the
electrodes.
12. The method of using of claim 8 further comprising the step of
pressurizing one or more of the electrodes with nitrogen gas.
13. The method of using of claim 8 wherein the current is pulsed
and has a duration that minimizes thermal conduction into the solid
centers of the sand grains.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Pursuant to 35 U.S.C. section 119(e), the present invention
claims the benefit of the filing date of U.S. provisional
application 60/767120 filed 4 Mar. 2006, the text of which is
included by reference herein.
FIELD OF INVENTION
[0002] In the field of hydrocarbon extraction from in-ground oil
sands or similar deposits, a device and method of using the device
for the extraction of the hydrocarbons.
BACKGROUND OF THE INVENTION
[0003] The invention is termed "IXOS," an acronym of sorts derived
from In-Situ Extraction of Hydrocarbons from Oil Sands." IXOS
employs an electric current between porous, tubular in-ground
electrodes to flow hydrocarbons in a deposit into the electrode.
Electric resistance heating of the oil-bearing fluid in the ground
between the electrodes creates a pressure gradient, which drives
hydrocarbon product into the electrodes. As long as the electrode
is porous, then product can be collected from within the electrode.
This method has not heretofore been used in any field relating to
the extraction of oil from the ground.
[0004] The method of the invention is estimated to require an
energy input equaling about 2% of the heating value of oil
recovered. This calculation is based on an average of oil content
of 14% by weight oil in the oil sand and 2% by weight of water and
assuming all the electrical energy can be directed into the
conductive water layer. This is a significant improvement over the
state of the art, and unlike any other method, allows a wide margin
for other heat losses in the process without impacting the energy
balance for oil production from the deposit.
[0005] Energy savings from the invention are maximized taking
advantage of the fact that the conductivity of oil sands is due to
the interstitial liquid, the dielectric sand grains themselves
having low conductivity. An electric current (flowing between
electrodes or induced) heats up this interstitial liquid
instantaneously, compared to steam flow and thermal conduction
previously used in the industry.
[0006] Oil sands, also referred to as tar sands and bituminous
sands, are a combination of clay, sand, water, and bitumen. Bitumen
is the soluble organic matter and is an asphalt-like substance,
which can be refined into oil. Oil sand deposits are typically
mined using strip-mining techniques, which extract the oils sands
from the ground for processing to recover the bitumen.
[0007] Tar sands deposits are found all over the world, with the
largest deposits found in Venezuela and Alberta, Canada. These two
deposits have been estimated to contain about 600 cubic kilometers
of oil sands, equivalent to about twice the world's reserves of oil
or about 3.5 trillion barrels of oil. The United States contains
scattered deposits of oil sands, mainly in Utah, Kentucky, Kansas,
Missouri, Oklahoma, California, and New Mexico. The ability to
economically recover these deposits would help to diversify oil
sources and contribute to U.S. national and energy security.
[0008] The invention may also be used for the extraction of oil in
similar deposits, for example, in oil shale. Oil shale is a general
term for shales rich enough in bituminous material to yield
petroleum upon heating in low oxygen environments. The United
States Office of Naval Petroleum and Oil Shale Reserves estimates a
world supply of oil shale of about 1,700 billion barrels of which
about 1,200 billion barrels is in the United States Estonia,
Russia, Brazil, and China.
DESCRIPTION OF PRIOR ART
[0009] In a common oil extraction process, hot water is added to
mined oil sand to liberate the bitumen from the sand and clay. The
resulting slurry is piped to an extraction plant where the slurry
is agitated to allow small air bubbles to attach to bitumen
droplets. Froth is created, which is skimmed off the top and
treated to remove residual water and fine solids. Bitumen is then
upgraded in a coker, which cracks the bitumen into lighter oils and
gases. Further processes create a blended synthetic crude oil.
[0010] An oil sands processing plant will typically consume over a
million gallons of water every hour. The more efficient of such
plants consume about 92 gallons of water per 42-gallon barrel of
syncrude produced. Such a plant could produce about 75 million
barrels of syncrude per year. Of the water used typically, about
250,000 gallons per hour is too contaminated with dissolved
hydrocarbons and minerals for recycling. This quantity is sent to a
tailings pond. While a tailings pond typically prevents
contaminated water from mixing with potable water supplies, this
much ponded water requires active management to permit settling of
fines, to prevent it from combining with clean surface water and to
preclude accidental release. The wet sand and clay residues can
also be caustic and require extensive and expensive neutralization.
This caustic aqueous residual often has a high Chemical Oxygen
Demand, which robs the water of oxygen. This, in turn, makes the
ponds containing such residual, hypoxic and adverse to plant and
animal life.
[0011] Improvements in the basic hot water process have been
disclosed, for example in U.S. Pat. No. 6,576,145 to Conaway on
Jun. 10, 2003. The '145 patent is a continuous process where the
mined oil sand is crushed to the particle size of sand or smaller,
then mixed with water to form a slurry, then heated and blended
with an oxidant in aqueous solution, such as hydrogen peroxide.
This process releases the free interstitial hydrocarbons and those
hydrocarbons bound electrostatically to the surfaces of clay-like
particles in the ore. This process attempts to reduce water
consumption through recycle and seeks to lower costs. However,
while improved, this process has many of the same shortfalls of the
basic hot water process.
[0012] It has been estimated that the equivalent of one barrel of
oil is needed to process three barrels of synthetic crude obtained
from oil sands using the hot water process. Aside from the cost,
this much energy consumption translates to significant emissions of
carbon dioxide, a greenhouse gas.
[0013] Five major disadvantages of producing oil from strip mined
oil sands are (1) the need to consume large quantities of clean
water resources, (2) the need to consume energy to heat the water,
(3) the subsequent pollution of the water by chemicals extracted
from the deposits, (4) a high cost of production; and (5) large up
front capital investment is needed partly because very large
separation plants are needed for processing the bitumen.
[0014] Since up to 80% of the oil sands deposits may be too deep
underground for strip mining, other mining techniques have been
employed. For example, in-situ mining techniques are practiced to
extract the bitumen without removing oil sands from their in-ground
location.
[0015] One such in-situ method requires a large source of steam, an
injection borehole and an extraction borehole. This method is
sometimes called "Steam-Assisted Gravity Drainage." The steam is
injected into the oil sands deposit where the combination of high
temperature and steam creates a largely gaseous product that will
flow and can be channeled to the extraction borehole. The product
flow is liquefied before reaching the surface and pumped out of the
extraction borehole. This in-situ technique suffers from the
disadvantages noted in the preceding paragraph for the aboveground
hot water process. In addition there is a potential for pollution
below the surface.
[0016] The current invention improves on Steam-Assisted Gravity
Drainage by employing controlled deposition of heat. In response to
a current pulse between electrodes, resistive ionic conduction
through paths of fluid interstitial to the dielectric grains in the
body of oil sand produces an overpressure pulse. This drives the
oil-bearing fluid towards the low-pressure outlets at the
electrodes. Instantaneous heating with the IXOS device is dominant
in the process. This compares to a slower rate of thermal
conductive heating using the steam process. Therefore, the
preferred embodiment of the present invention, which employs a high
current pulse of short duration, offers significant benefits over
steam extraction by minimizing wasted energy otherwise used for
warming the ore (sand) in the deposit.
[0017] Another such in-situ method uses dissolution chemicals to
dissolve the bitumen. The dissolved bitumen then flows to an
extraction point, where it is removed for processing to extract the
oil and recycle the dissolution chemicals.
[0018] All of the existing methods of extracting oil from oil sands
have a large environmental cost. When strip mining is employed, two
tons of mined sand are required to produce one barrel of synthetic
crude. This leaves a significant tailings pile. The water ponds
required to dispose of the water used in the process are
contaminated and consume large tracts of land. Such underground
processes also have potential to contaminate water aquifers.
[0019] The preferred embodiments of the device and method of the
invention address many of the deficiencies found in the state of
the art of oil extraction from oil sands. In particular, the
present invention provides an in-situ process similar to an oil
well, while eliminating extraction of oil sands and recovery of
dissolution chemicals.
[0020] The preferred embodiment of the invention simplifies the
process of oil extraction from oil sands by eliminating much of the
surface infrastructure required to extract the oil sands and
bitumen from the ground.
[0021] The preferred embodiment of the invention eliminates the
need to consume large quantities of clean water resources. No water
is used in the IXOS extraction process, except for the water
already present in the deposit. Water is used only to provide
minimal equipment cooling and to satisfy minor process needs.
[0022] The preferred embodiment of the invention avoids most of the
cost, pollution and energy associated with the use of water and
dissolution chemicals in the current methods. The preferred
embodiment of the invention will help with minimization of cost,
both in capital equipment and operation. The cost of electrical
power is offset by low energy requirements. The costs for energy
for extracting the bitumen are estimated to be about 2 percent of
heating value of the oil recovered.
[0023] Pollution and energy are reduced as a necessary consequence
of not using water and not needing to consume energy for heating
water. Of major importance is the environmentally non-intrusive
nature of in-situ production.
[0024] In terms of heating oil shale deposits for removing the oil,
U.S. Pat. No. 6,929,067 to Vinegar, et al. on Aug. 16, 2005, which
is incorporated by reference as if fully set forth herein, provides
a thorough reference and description of heat sources with
conductive material for in situ thermal processing of an oil shale
formation. Essentially, the state of the art for electricity driven
heating methods described involve electrically-powered, resistive
heating elements placed in a well bore drilled into the formation.
The heating elements are energized, much like that on an electric
stovetop, and the heat generated by the elements is either carried
to the formation by conduction or by radiation.
[0025] The preferred embodiment of the invention is different from
all of the prior art described in the '067 patent in that this
embodiment uses the in situ formation itself as the medium for
carrying a current and, thus, heating itself from the flow of
current.
[0026] It is therefore apparent that a need exists for a non-water
consuming process for extracting oil from oil sands. It is further
apparent that such a process that is also lower-cost, lower
polluting, and lower energy process would significantly enhance the
state of the art for producing oil from oil sands.
BRIEF SUMMARY OF THE INVENTION
[0027] A device and method of using the device provide for in-situ
extraction of hydrocarbons from oil sands and other hydrocarbon
resources. The preferred embodiment of the device includes at least
two electrodes of tubular form wherein said electrodes are porous
and capable of being inserted into the ground; a source of
electrical current to apply to the electrodes; and a means for
extracting the hydrocarbons from the tubular electrodes. In the
preferred embodiment of the method of the invention, the electrodes
are inserted into the oil deposit and connected to an electrical
potential difference sufficient to drive an electric current
between in-ground electrodes. Current is then flowed between the
electrodes. The pressure gradient, resulting from heating the
oil-bearing fluid, drives product into the tubular electrodes where
it is removed.
BRIEF DESCRIPTION OF THE DRAWING
[0028] The drawing is a sectional view of the tubular porous
electrodes for the in-situ extraction of oil from oil sands.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The device and method of using the device for the in-situ
extraction of hydrocarbons from oil sand (herein referred to as
"IXOS") are based on the using the ionic resistivity of the
hydrocarbon formation, also referred to as a deposit, by passing a
current between electrodes in the formation.
[0030] The preferred embodiment of the IXOS device first includes a
plurality of tubular porous electrodes similar to the one shown in
the drawing. The tubular shape is typical of a well pipe or casing
used in the oil industry. The porosity of the electrodes may be
obtained by employing perforations, for example in the form of a
pattern of short vertical slots (30) in the wall of the electrode
tubes.
[0031] The electrodes are also similar to well-known technology of
well points used for ground water extraction in that they are
suitable for being inserted into the ground. While well points are
porous casings used to extract water from an in ground well, the
electrodes are used to extract hydrocarbons, such as soil
containing a deposit of oil. Two significant differences from well
point technology are the ability of the electrodes to carry
electrical current for heating the ground deposit, and a consequent
ability to motivate flow of the hydrocarbons from the ground
resource into the hollow body of an electrode incident to
extraction. In the preferred embodiment, the flow of electrical
current between two or more electrodes is what motivates the
flow.
[0032] The diameter and length of the electrodes can vary as
required by the resource deposit. Typically, the electrodes would
be steel tubes or casings (10) of about six-inches in diameter with
a thickness of copper (20) on the inner wall to serve as a current
carrier. However, electrode diameters of 10 feet, 20 feet or more
are also within the scope of the invention. The length of the
electrode is limited only by practicality constraints of handling
and insertion into the deposit. Short lengths of electrodes may be
joined in the same manner as well piping to make the electrode
length any desired length suitable to the deposit and the source of
power. Similar to a well point, an electrode may be fitted to the
end of a pipe or casing. However, unlike a well point, the
electrode must be insulated from the pipe or casing so that it is
capable of delivering current to the specific resource location in
the ground. At least two electrodes are needed in the preferred
embodiment for the operation of the invention, and there is no
limit on how many may be used.
[0033] The preferred embodiment of the IXOS device next includes a
means for extracting the hydrocarbons from the tubular electrodes.
In this embodiment, this means for extracting is a valve that is
opened to allow the pressurized hydrocarbons and steam to flow out
of the electrodes. In alternative embodiments, this means for
extracting is a pump, which, for example, may either be placed
within the electrode or on the surface.
[0034] The preferred embodiment of the IXOS device lastly includes
a source of electrical current to apply to the electrodes. This
typically means applying an electrical potential difference across
two or more electrodes so that current will flow between them.
Alternating or direct current may be employed.
[0035] In using the preferred embodiment of the IXOS device, the
electrodes are inserted into the hydrocarbon containing deposit a
distance from each other. Such distance is dependent upon the
electrical resistivity of the ground and the electrical potential
difference available to apply between electrodes. The determining
factor is that the current passing through the deposit and between
the electrodes must be sufficient to heat the deposit. Typically
with tens of kilovolts available to apply to the electrodes, the
electrodes would be spaced tens of meters apart.
[0036] In the preferred embodiment, the casings are vertical in
orientation, but they may be in any orientation as long as they
provide access to the surface so that the hydrocarbons can be
removed from the tubular electrodes.
[0037] In the preferred embodiment of the method of the invention,
a potential difference is applied between electrodes so that a
current runs between them sufficient to heat the ground, that is,
the deposit between the electrodes. For example, a 60 Hz potential
difference in the range of several kilovolts causes an ionic
current distribution in the conductive interstitial medium between
the grains in the oil sand. Ionic resistance will generate local
heating within the interstitial medium, causing the sequential
melting of ice, the dislodging of oil particles, and pressure
buildup through steam formation. Thus, the preferred embodiment of
the invention avoids unnecessary heating of the bulk of the ore
(sand) both by placing the heat exactly where it is needed (in the
interstitial liquid), and by forestalling thermal conductivity
losses. These embodiments take advantage of the benefit obtainable
by employing a large current pulse of short duration to minimize
conductive heat losses and to build high pressure for expelling
product.
[0038] While the invention includes the application of a small
current over a long time, embodiments of this type are less
efficient in product delivery and more wasteful of energy. Such
embodiments will work, but they promote less useful conductive
heating of the bulk sands, and deliver a comparatively weak
pressure rise from the vaporized liquids, which drive product into
the electrode wells.
[0039] The preferred embodiment employs a current of about 1,000
amps delivered over a duration from about 20 seconds to 2 minutes.
The current density can be reduced by increasing the diameter of
the electrode. In one embodiment, pulsed current is generated on
site using a motor and flywheel configured such that after the
flywheel reaches a rotation corresponding to the energy desired,
that rotational energy is discharged by turning a generator, which
creates the desired pulse of electrical current.
[0040] A porous electrode allows ingress of steam-driven oil while
keeping out sand grains. In this way each electrode essentially
becomes a production well. The means for extracting the
hydrocarbons is employed to produce oil and other hydrocarbons from
the deposit.
[0041] The process works most efficiently when the current passing
between electrodes is of such magnitude and duration that it does
not directly heat the dielectric quartz sand grains. Thus, for the
preferred embodiment, such current is pulsed and has a duration
that minimizes thermal conduction into the solid centers of the
sand grains. For this to occur, the resistive heating is applied
rapidly enough to suppress to some extent the thermal conduction
into the solid centers of the sand grains. This saves on energy
consumed by the extraction process and contributes to an efficient
process.
[0042] Important aspects of the process of using the invention are
the modes of flexibility for adapting to different ground
conditions present in a deposit.
[0043] A primary mode of flexibility relates to the electrodes,
which can easily be rearranged and adapted to different conditions
without the construction of new equipment. Hardness of the sand
deposit and viscosity may vary radically with seasonal temperature
changes, and the composition and physical nature of oil sands may
differ substantially from one geographical location to another. In
particular, this process is suitable for locations where the
deposit, for example oil sand, is under large overburdens. In such
cases, the embodiment would include electrically insulating sleeves
over the electrodes where the electrodes are in contact with the
overburden. Also, an alternative embodiment employed in such cases,
comprises the electrode at the end of a casing penetrating the
overburden wherein the electrode is electrically insulated from the
casing. The presence of an overburden is expected to be of benefit
when it acts as a seal for trapping vapor pressure.
[0044] Further modes of flexibility involve adjustable variables
for optimizing the extraction of hydrocarbon from the deposit.
These include voltage and frequency, geometry of electrode matrix,
and time structure of electrical current.
[0045] In an alternative embodiment of the method of using the
device, there is an additional step of injecting an electrolyte
into the deposit. For example, in an oil sand deposit, salt water
is injected through the electrode slots to raise conductivity of
the deposit and to clear sand blockages of the electrode slots.
[0046] In an alternative embodiment of the method of using the IXOS
device, there is an additional step of pressurizing one or more of
the electrodes with nitrogen gas. This step helps to drive the oil
product to unpressurized adjacent electrodes.
[0047] The description above and the examples noted are not
intended to be the only embodiments of this invention and should
not be construed as limiting the scope of the invention. These
examples merely provide illustrations of some of the embodiments of
this invention. Others will be obvious to those skilled in the art.
Thus, the scope of the invention is determined by the appended
claims and their legal equivalents rather than by the examples
given.
* * * * *