U.S. patent application number 16/133896 was filed with the patent office on 2019-04-04 for composition for preventing formation of water-oil emulsions using additives.
The applicant listed for this patent is Saudi Arabian Oil Company. Invention is credited to Abdullah S. Al-Ghamdi, Haitham Aljahani, Enrico Bovero, Aziz Fihri, Remi Mahfouz, Abdullah A. Shahrani, Ihsan Taie.
Application Number | 20190100688 16/133896 |
Document ID | / |
Family ID | 64049705 |
Filed Date | 2019-04-04 |
United States Patent
Application |
20190100688 |
Kind Code |
A1 |
Mahfouz; Remi ; et
al. |
April 4, 2019 |
COMPOSITION FOR PREVENTING FORMATION OF WATER-OIL EMULSIONS USING
ADDITIVES
Abstract
A method of preventing formation of a water and oil emulsion in
a downhole formation containing oil, the method comprises preparing
a dispersion of water and a plurality of non-functionalized
nanoparticles, each nanoparticle in the plurality of nanoparticles
having a size of at least 300 nanometers, and injecting the mixture
downhole into contact with the oil downhole. Presence of the
plurality of nanoparticles prevents formation of an emulsion
between the injected water and the oil.
Inventors: |
Mahfouz; Remi; (Lyon,
FR) ; Fihri; Aziz; (Paris, FR) ; Bovero;
Enrico; (Dhahran, SA) ; Shahrani; Abdullah A.;
(Dammam, SA) ; Aljahani; Haitham; (Khobar, SA)
; Al-Ghamdi; Abdullah S.; (Dammam, SA) ; Taie;
Ihsan; (Dhahran, SA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Saudi Arabian Oil Company |
Dhahran |
|
SA |
|
|
Family ID: |
64049705 |
Appl. No.: |
16/133896 |
Filed: |
September 18, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16051678 |
Aug 1, 2018 |
10131830 |
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16133896 |
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15723818 |
Oct 3, 2017 |
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16051678 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C09K 8/58 20130101; C09K
2208/10 20130101; C09K 8/536 20130101; B01D 17/12 20130101; B01D
17/047 20130101; B01D 17/041 20130101 |
International
Class: |
C09K 8/58 20060101
C09K008/58; C09K 8/536 20060101 C09K008/536 |
Claims
1-7. (canceled)
8. A composition for use in preventing formation of water and oil
emulsions comprising a dispersion of a plurality of
non-functionalized nanoparticles, each of the nanoparticles having
a size of at least 300 nanometers dispersed in water.
9. The composition of claim 8, wherein the plurality of
nanoparticles is composed of silica.
10. The composition of claim 8, wherein the water is distilled and
the plurality of nanoparticles are dispersed in the water at a
concentration of approximately 0.2 weight percent.
11. The composition of claim 8, wherein the water further includes
salt, and the plurality of nanoparticles are dispersed in the water
at a concentration of approximately 1.6 weight percent.
12. The composition of claim 11, wherein the water has a salt
concentration of approximately 3.5 weight percent.
13. The composition of claim 8, wherein each of the nanoparticles
in the plurality of nanoparticles has a size in a range of 300 to
500 nanometers.
14. The composition of claim 13, wherein the plurality of
nanoparticles of uniform size within the range.
15. The composition of claim 8, wherein the water is distilled.
16. The composition of claim 8, wherein the plurality of
nanoparticles are dispersed in the water at a concentration of
approximately 0.2 weight percent.
17. The composition of claim 8, wherein the water further includes
salt.
18. A composition for use in preventing formation of water and oil
emulsions comprising a dispersion of a plurality of nanoparticles
having a surface with surface properties, wherein each of the
nanoparticles has a size of at least 300 nanometers dispersed in
water, and wherein the nanoparticles free of any chemical species
or groups which modify surface properties thereof.
19. The composition of claim 18, wherein the plurality of
nanoparticles is composed of silica.
20. The composition of claim 18, wherein the water is distilled and
the plurality of nanoparticles are dispersed in the water at a
concentration of approximately 0.2 weight percent.
21. The composition of claim 18, wherein the water further includes
salt, and the plurality of nanoparticles are dispersed in the water
at a concentration of approximately 1.6 weight percent.
22. The composition of claim 21, wherein the water has a salt
concentration of approximately 3.5 weight percent.
23. The composition of claim 18, wherein each of the nanoparticles
in the plurality of nanoparticles has a size in a range of 300 to
500 nanometers.
24. The composition of claim 23, wherein the plurality of
nanoparticles of uniform size within the range.
25. The composition of claim 18, wherein the water is
distilled.
26. The composition of claim 18, wherein the plurality of
nanoparticles is dispersed in the water at a concentration of
approximately 0.2 weight percent.
27. The composition of claim 18, wherein the water further includes
salt.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation-in-part of U.S.
patent application Ser. No. 15/723,818, filed on Oct. 3, 2017, now
allowed, entitled Method for Preventing Formation of Water-Oil
Emulsions Using Additives.
FIELD OF THE INVENTION
[0002] The present invention relates to the problem of preventing
formation of water-oil emulsions to enhance oil recovery in the oil
and gas industry. In particular, the present invention relates to a
method for separating water and oil emulsions using additives at
various stages of the oil production process.
BACKGROUND OF THE INVENTION
[0003] During downhole oil extraction, water is injected to apply
pressure and aid in the forcing of oil out of tight formations in
reservoirs. A disadvantageous effect of adding water is the
production of oil-water emulsions, from which the oil portion is
challenging to extract. Water-oil emulsions can also be formed at
other stages and locations including during drilling, producing,
transporting and processing, in hydrocarbon reservoirs, well bores,
surface facilities, transportation systems and refineries. During
field production, as the percentage of the water in the emulsions,
known as the "water cut" can reach to up to 90% of the total.
[0004] An emulsion is generally defined as a heterogeneous liquid
system consisting of two immiscible liquids where one the liquids
is totally dispersed as droplets in the second liquid. The
emulsions can be classified into three broad groups: water in oil
(W/O), oil in water (O/W) and multiple or complex emulsions. The
formation and the stability of water-oil emulsions have been widely
investigated. The stability and enhancement of emulsions formation
can be affected by several parameters such as water/oil ratio,
emulsifier/surfactant ratio, the presence of solids, surface
tension, presence of a high boiling point fraction (e.g.
asphaltenes, resins, organic acids), temperature, salinity and
pH.
[0005] Techniques are currently in development to enhance the water
injection performance and reduce the water cut during the
production life of oil reservoir. These techniques seeks to
minimize the added water using inflow control devices, treat and
dispose water at the surface, and separate water from oil downhole
in reservoirs. Specific techniques and mechanism include
hydrocyclone, gravity separators, and centrifugal separator for
separation of oil from water coupled with supplemental technologies
such as mechanical blocking devices (e.g. packer and plugs) and
water additives (e.g., polymer gel, nanoparticles).
[0006] In the past decade, studies showed that nanoparticle
additives including metal oxides and carbon nanotubes can be used
to enhance the oil recovery. Due to their characteristics including
wettability, interfacial tension reduction and viscosity
modification capability, and their stability in injected fluid,
nanoparticles are potential candidates to be used to increase oil
recover from water-oil emulsions.
[0007] However, the techniques disclosed to date employ
combinations of particles with chemical additives, and utilize
particle size ranges (<50 nanometers) that are suited for
combinations with the chemical additives.
[0008] What is therefore needed is a cost-effective,
easy-to-implement and effective technique for separating or
preventing water-oil emulsions at various stages of the oil
production process.
SUMMARY OF THE INVENTION
[0009] Embodiments of the present invention provide a method of
preventing formation of a water and oil emulsion in a downhole
formation. The method comprises preparing a dispersion of water and
a plurality of non-functionalized nanoparticles, each nanoparticle
in the plurality of nanoparticles having a size of at least 300
nanometers (e.g., a diameter), and injecting the mixture downhole
into contact with the oil downhole. Presence of the plurality of
nanoparticles prevents formation of an emulsion between the
injected water and the oil.
[0010] In certain embodiments, the plurality of nanoparticles
comprise silica. Regardless of whether the nanoparticles are
silica, in certain embodiments the nanoparticles have surfaces that
are free of any surface modification. In such embodiments, the
nanoparticles are "pure," as discussed below, and, as such, lack
any chemical groups which modify the surface properties of the
nanoparticles.
[0011] In some implementations, the water injected is distilled,
and the plurality of nanoparticles are dispersed in the water at a
concentration of approximately 0.2 weight percent. In other
implementations, in which the water contains salt, the plurality of
nanoparticles are dispersed in the water at a concentration of
approximately 1.6 weight percent. In implementations that employ
salt water, the salt water used can have a salt concentration of up
to approximately 3.5 weight percent.
[0012] Each of the nanoparticles in the plurality of nanoparticles
preferably has a size (e.g., a diameter) in a range of about 300
nanometers to about 500 nanometers.
[0013] Embodiments of the present invention also include a
composition for use in preventing formation of water and oil
emulsions comprising a dispersion of water and a plurality of
non-functionalized nanoparticles, each nanoparticle in the
plurality of nanoparticles having a size (e.g., a diameter) of at
least 300 nanometers. In preferred embodiments, the plurality of
nanoparticles are composed of silica and each has a size (e.g., a
diameter) in a range of about 300 nanometers to about 500
nanometers.
[0014] In some implementations the water is distilled and the
plurality of nanoparticles are dispersed in the water at a
concentration of approximately 0.2 weight percent. In other
implementations, the water further includes salt, and the plurality
of nanoparticles are dispersed in the water at a concentration of
approximately 1.6 weight percent. In implementations that employ
salt water, the salt water used can have a salt concentration of
approximately 3.5 weight percent.
[0015] Any combinations of the various embodiments and
implementations disclosed herein can be used.
[0016] These and other aspects, features, and advantages can be
appreciated from the following description of certain embodiments
of the invention and the accompanying drawing figures and
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic illustration of an exemplary apparatus
for testing separation of water and oil using the ASTM D-1401
standard with which the compositions according to the present
invention were tested.
[0018] FIG. 2 is a schematic cross-section of an oil production
drill-hole into which water with nanoparticles according to
embodiments of the present invention can be injected to prevent
emulsion formation.
DETAILED DESCRIPTION CERTAIN OF EMBODIMENTS OF THE INVENTION
[0019] The disclosure herein pertains to a method of separating oil
from the water in emulsions by addition of nanoparticles. In
particular, the inventors have determined that water of low salt
concentration can be separated from oil in emulsions by addition of
nanoparticles of over 300 nanometers in size, at a concentration of
approximately 0.2% (W.sub.particles/W.sub.water) or higher, and
that salty water can be separated from oil in emulsions by addition
of similarly-sized nanoparticles at a concentration of
approximately 1.6% (W.sub.pt/W.sub.wt) or higher. The nanoparticles
can be added with water injection to separate emulsions in downhole
locations.
[0020] Nanoparticles are often functionalized to modify their
properties such as by the introduction of functional groups.
Functionalization is the chemical modification of the surface of
nanoparticles, typically with organic or polymer molecules. The
addition of such chemical groups to the surface of the
nanoparticles is used to modify properties including surface
properties such as hydrophilicity, hydrophobicity, conductivity and
resistance to corrosion. Functionalization of nanoparticles
requires one or more steps to act upon the nanoparticles to modify
their properties. A non-functionalized nanoparticle has not
undergone steps to modify its properties, including the surface
properties of the nanoparticle, and in this respect are "pure"
nanoparticles. Pure nanoparticles lack any chemical groups which
modify the surface properties.
[0021] While functionalization to modify properties is not ruled
out in various embodiments, the inventors have found that the
nanoparticles of over 300 nanometers in size are suitable to
demulsify water from oil without functionalization, and, more
specifically, free of (without) any surface modification with
additional chemical species. Therefore, in some embodiments, it is
intended that the nanoparticles used for demulsification be
non-functionalized.
[0022] In embodiments in which the nanoparticles are spherical, the
diameter is preferably over 300 nanometers, and more preferably in
a range between about 300 nanometers and about 500 nanometers.
[0023] Experiments have been conducted to investigate the behavior
of water (both distilled and salty (3.5%)) having dispersions of
silica nanoparticles of varying concentrations and sizes on the
formation of emulsions with Arabian heavy crude oil. The silica
nanoparticles used in the experiments were synthesized at different
sizes (30 nm 100 nm, 200 nm and 350 nm) using the Stober process
which is used to prepare silica particles of uniform size. The
nanoparticles were dispersed in the distilled water and salty water
by sonication for 1 hour free of (that is, without any) additional
steps of functionalization of the nanoparticles. The resulting
slurry was used as a component with Arabian crude oil for testing
their ability to separate water-oil emulsions. The testing employed
the ASTM D-1401 standard (the American Society for Testing and
Materials "Standard Test Method for Water Separability of Petroleum
Oils and Synthetic Fluids").
[0024] FIG. 1 is a schematic illustration of an exemplary test
apparatus 100 that can be used in the ASTM D-1401 test method. The
test apparatus comprises a first container 110 containing a bath of
water 112 having a controllable using a thermocouple 114. Placed
within first container 110 is a graduated cylinder 120 of, for
example, 100 ml capacity. In the test, graduated cylinder 120 is
filled up to a first level (e.g., 40 ml) with a layer of distilled
or salty water 125. On top of the water layer 125, graduated
cylinder 120 is filled to a second level (e.g., 80 ml) with a layer
of crude oil 130. In order to mix the water layer 125 with the
crude oil layer 130, a mechanical stirrer 140 is disposed within
the cylinder 120 and operative to rotate at a high rate (e.g., 1500
rpm).
[0025] In the experiments conducted, the water bath 112 was
maintained at either 54.degree. C. or 82.degree. C., depending on
the viscosity of the test specimen or sample specification. The
mechanical stirrer 140 was operated to stir layers 125, 130 at 1500
rpm for 5 minutes, sufficient to thoroughly mix the water and oil
phases into a single phase emulsion. The fluid in the cylinder 120
was carefully observed and recordings were made until final
separation of the emulsion occurred. The test results at different
particles size, concentration and medium are summarized in Table 1
directly below.
TABLE-US-00001 TABLE 1 Par- Water/ Weight % ticles Separation Oil
Particles size Emulsion Volume after Ratio Water Type in Water (nm)
formation test 1.sub.v/1.sub.v Distilled 0 -- Full Non
1.sub.v/1.sub.v Distilled 0.2 30 Full Non 1.sub.v/1.sub.v Distilled
1.6 30 Full Non 1.sub.v/1.sub.v Distilled 0.2 100 Full Non
1.sub.v/1.sub.v Distilled 0.2 200 Full Non 1.sub.v/1.sub.v
Distilled 0.4 200 Full Non 1.sub.v/1.sub.v Distilled 0.2 350 Yes- 4
ml 1 min--- 32 ml 5 min----36 ml 1.sub.v/1.sub.v Salty (3.5%) 0 --
Full Non 1.sub.v/1.sub.v Salty (3.5%) 0.2 350 Full Non
1.sub.v/1.sub.v Salty (3.5%) 0.4 350 Full Non 1.sub.v/1.sub.v Salty
(3.5%) 0.8 350 Full Non 1.sub.v/1.sub.v Salty (3.5%) 1.6 350 Yes- 8
ml 1 min -- 22 ml 2 min -- 26 ml 5 min -- 30 ml 10 min -- 32 ml
1.sub.v/1.sub.v Salty (3.5%) 3 350 Yes- 7 ml 5 min -- 20 ml 7 min
-- 25 ml 10 min -- 30 ml 30 min -- 33 ml
[0026] As can be discerned from the results shown in Table 1 above,
in distilled water, silica nanoparticles of 350 nm size
demonstrated very effective separation behavior at low
concentration of 0.2% (W.sub.particles/W.sub.water). At 350 nm, 36
ml volume of separated fluid was obtained with the particles are
still present in the water phase. In contrast, silica nanoparticles
with particles size <200 nm did not demonstrate comparable
separation behavior even at higher concentrations of 0.4 or 1.6%
(W.sub.particles/W.sub.water). Instead, a single phase
non-separated emulsion was obtained at different concentrations and
different particles sizes (30 nm, 100 nm and 200 nm).
[0027] Due to their demonstrated ability to separate water-oil
emulsions in distilled water, the 350 nm size silica nanoparticles
were also selected for emulsions tests with salty water (3.5% salt
concentration). The results of the salt water tests demonstrate
that the concentration of nanoparticles has a pronounced impact on
the separation effect. At under 0.8% M.sub.particles/M.sub.salty
water (i.e., 0.2% and 0.4%), the nanoparticles did not shows
effectiveness in demulsification, as the emulsion remained stable
for 24 hours. At the higher 1.6% concentration level, 33 ml of
separation was obtained after 10 min. These results indicate that
in salty water the separation effect of the silica nanoparticles
tends to be slower and less effective than in distilled water. For
instance, in distilled water 36 ml of separation were obtained
within 5 minutes, whereas in salty water, separation of only 33 ml
was obtained after 10 minutes, twice as long. However, when the
concentration of nanoparticles was increased further to 3%, results
did not show any improvement in separation ability. Accordingly, it
is found that 1.6% is an optimal nanoparticle concentration (using
350 nm nanoparticles) for salty water-oil separation. Accordingly,
for downhole water injection, the test results indicate use of
silica nanoparticles with particles size >300 nm and a
concentration of 0.2% in distilled water, and at 1.6% in salty
water (3.5%), in order to reduce the emulsion formation in the
reservoir. This process will help to reduce the water cut in
downhole reservoir and then will improve the oil recovery and
increase the oil production.
[0028] In addition, in order to clearly demonstrate the effect of
silica nanoparticles, a blank test (control) was included using
distilled water and salty water with the Arabian Heavy crude
without silica nanoparticles. In this case, the emulsions remained
stable after 24 hours of the test.
[0029] FIG. 2 is a schematic cross-section of an oil production
drill-hole 200. The drill-hole has a depth that reaches a downhole
oil reservoir. A water pump 220 is situated within the drill-hole
200 is operative to inject water at pressure through later water
outlets 225 in the drill hole. Ideally, the water that is injected
exerts pressure on overlying oil deposits without mixing with the
oil. In this manner, the injected water forms a water column 230,
separate from an oil column 240. The pressure that the injected
water exerts on the oil column forces oil to flow through lateral
inlets 250 into the drill hole, and eventually through an outlet
255. Similarly, injected water cycles back to the drill hole
through water inlets 260. A series of valves e.g., 270 are
operative to keep oil that enters drill-hole 200 through inlets 250
separate from the water that enters the drill hole through inlets
260.
[0030] In practice, as noted in the Background section above, it is
difficult to keep the downhole oil and water phases completely
separate from one another without added measures, particularly as
the phases are under pressure. By adding silica nanoparticles of
300 nanometers or greater at the concentrations appropriate for the
water salinity with the injected water, it is possible to promote
and maintain the separation of the oil and water phases in the
downhole formation. By keeping the phases separate, the oil that
flows into the drill hole tends to have a low water content.
[0031] The composition of water and nanoparticles 300 to 500
nanometers in size is cost-effective, plentifully available,
eco-friendly and has high water-oil separation efficiency at low
loading. These advantages make this composition an attractive
alternative to other separation methods that do not have this
combination of characteristics. The production of nanoparticles can
also be scaled up to the levels suitable for large oil production
facilities. When used at large scale, it is expected that the
techniques of the present invention can have an appreciable effect
on reducing water cut and improving the efficiency of oil
recovery.
[0032] It is to be understood that any structural and functional
details disclosed herein are not to be interpreted as limiting the
systems and methods, but rather are provided as a representative
embodiment and/or arrangement for teaching one skilled in the art
one or more ways to implement the methods.
[0033] It is to be further understood that like numerals in the
drawings represent like elements through the several figures, and
that not all components and/or steps described and illustrated with
reference to the figures are required for all embodiments or
arrangements
[0034] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising", when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
[0035] Terms of orientation are used herein merely for purposes of
convention and referencing, and are not to be construed as
limiting. However, it is recognized these terms could be used with
reference to a viewer. Accordingly, no limitations are implied or
to be inferred.
[0036] Also, the phraseology and terminology used herein is for the
purpose of description and should not be regarded as limiting. The
use of "including," "comprising," or "having," "containing,"
"involving," and variations thereof herein, is meant to encompass
the items listed thereafter and equivalents thereof as well as
additional items.
[0037] While the invention has been described with reference to
exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications will be
appreciated by those skilled in the art to adapt a particular
instrument, situation or material to the teachings of the invention
without departing from the essential scope thereof. Therefore, it
is intended that the invention not be limited to the particular
embodiment disclosed as the best mode contemplated for carrying out
this invention, but that the invention will include all embodiments
falling within the scope of the appended claims.
* * * * *