U.S. patent application number 15/440821 was filed with the patent office on 2017-06-08 for lubricity agents to increase pump efficiency in hydrate inhibitor applications.
This patent application is currently assigned to BAKER HUGHES INCORPORATED. The applicant listed for this patent is BAKER HUGHES INCORPORATED. Invention is credited to PAUL J. BIGGERSTAFF, ANNA M. DHUET, MARC N. LEHMANN, JERRY J. WEERS.
Application Number | 20170158944 15/440821 |
Document ID | / |
Family ID | 48427501 |
Filed Date | 2017-06-08 |
United States Patent
Application |
20170158944 |
Kind Code |
A1 |
BIGGERSTAFF; PAUL J. ; et
al. |
June 8, 2017 |
LUBRICITY AGENTS TO INCREASE PUMP EFFICIENCY IN HYDRATE INHIBITOR
APPLICATIONS
Abstract
Saturated and unsaturated carboxylic fatty acids and alkylamine
salts, alkyl esters and alkyl amide derivatives of these fatty
acids are effective in improving the lubricity of hydrate inhibitor
formulations, thereby effectively reducing the level of wear on
moving parts of a pump under a load during pumping of the hydrate
inhibitor formulation, for instance into an umbilical for a subsea
hydrocarbon production operation.
Inventors: |
BIGGERSTAFF; PAUL J.; (Sugar
Land, TX) ; LEHMANN; MARC N.; (Houston, TX) ;
DHUET; ANNA M.; (Richmond, TX) ; WEERS; JERRY J.;
(Richmond, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BAKER HUGHES INCORPORATED |
Houston |
TX |
US |
|
|
Assignee: |
BAKER HUGHES INCORPORATED
Houston
TX
|
Family ID: |
48427501 |
Appl. No.: |
15/440821 |
Filed: |
February 23, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13671374 |
Nov 7, 2012 |
9605196 |
|
|
15440821 |
|
|
|
|
61561010 |
Nov 17, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C09K 8/52 20130101; C09K
2208/22 20130101; C09K 2208/32 20130101; C09K 2208/34 20130101;
F17D 3/12 20130101 |
International
Class: |
C09K 8/52 20060101
C09K008/52; F17D 3/12 20060101 F17D003/12 |
Claims
1. A hydrate inhibitor composition comprising: at least one alcohol
hydrate inhibitor selected from the group consisting of methanol,
ethanol, monoethylene glycol, triethylene glycol and combinations
thereof; and about 25 ppm to about 20,000 ppm of at least one
lubricity agent to increase lubricity of the hydrate inhibitor
composition, where the at least one lubricity agent is selected
from the group consisting of at least one C1-C36 carboxylic fatty
acid, an alkyl ester of a C1-C36 fatty acid, an alkylphenol ester
of a C1-C36 fatty acid, an anhydride salt of a C1-C36 fatty acid,
an alkanol amide of a C1-C36 fatty acid, an alkyl amide of a C1-C36
fatty acid, and combinations thereof and combinations thereof,
where the lubricity agent is different from the at least one
hydrate inhibitor.
2. The hydrate inhibitor composition of claim 1 where the hydrate
inhibitor is selected from the group consisting of: 0.01 to 99.99
vol % of the at least one alcohol hydrate inhibitor; 0.01 to 99.99
vol % of a low dose hydrate inhibitor (LDHI) selected from the
group consisting of anti-agglomerants (AAs) kinetic hydrate
inhibitors (KHIs) and combinations thereof; and combinations
thereof.
3. The hydrate inhibitor composition of claim 1 where the fatty
acid of the lubricity agent is derived from naturally-occurring
fats, naturally-occurring oils, oligomers of naturally-occurring
fats, oligomers of naturally-occurring oils, and combinations
thereof.
4. The hydrate inhibitor composition of claim 1 where the fatty
acid is tall oil fatty acid (TOFA).
5. The hydrate inhibitor composition of claim 1 where the amount of
lubricity agent in the hydrate inhibitor composition ranges from
about 100 ppm to about 500 ppm.
6. The hydrate inhibitor composition of claim 1 further comprising
a corrosion inhibitor. A hydrate inhibitor composition comprising:
0.01 to 99.99 vol % of at least one alcohol hydrate inhibitor
selected from the group consisting of methanol, ethanol,
monoethylene glycol, triethylene glycol and combinations thereof,
based on the total hydrate inhibitor; 0.01 to 99.99 vol % of a low
dose hydrate inhibitor (LDHI) selected from the group consisting of
anti-agglomerants (AAs) kinetic hydrate inhibitors (KHIs) and
combinations thereof, based on the total hydrate inhibitor; and
about 25 ppm to about 20,000 ppm of at least one lubricity agent to
increase lubricity of the hydrate inhibitor composition, where the
at least one lubricity agent is selected from the group consisting
of at least one C1-C36 carboxylic fatty acid, an alkyl ester of a
C1-C36 fatty acid, an alkylphenol ester of a C1-C36 fatty acid, an
anhydride salt of a C1-C36 fatty acid, an alkanol amide of a C1-C36
fatty acid, an alkyl amide of a C1-C36 fatty acid, and combinations
thereof and combinations thereof, where the lubricity agent is
different from the at least one hydrate inhibitor; where the fatty
acid of the lubricity agent is derived from naturally-occurring
fats, naturally-occurring oils, oligomers of naturally-occurring
fats, oligomers of naturally-occurring oils, and combinations
thereof.
8. The hydrate inhibitor composition of claim 7 where the fatty
acid is tall oil fatty acid (TOFA).
9. The hydrate inhibitor composition of claim 7 where the amount of
lubricity agent in the hydrate inhibitor composition ranges from
about 100 ppm to about 500 ppm.
10. The hydrate inhibitor composition of claim 7 further comprising
a corrosion inhibitor.
11. A hydrate inhibitor composition consisting essentially of: at
least one alcohol hydrate inhibitor selected from the group
consisting of methanol, ethanol, monoethylene glycol, triethylene
glycol and combinations thereof; about 25 ppm to about 20,000 ppm
of at least one lubricity agent to increase lubricity of the
hydrate inhibitor composition, where the at least one lubricity
agent is selected from the group consisting of at least one C1-C36
carboxylic fatty acid, an alkyl ester of a C1-C36 fatty acid, an
alkylphenol ester of a C1-C36 fatty acid, an anhydride salt of a
C1-C36 fatty acid, an alkanol amide of a C1-C36 fatty acid, an
alkyl amide of a C1-C36 fatty acid, and combinations thereof and
combinations thereof, where the lubricity agent is different from
the at least one hydrate inhibitor; and optionally a corrosion
inhibitor.
12. The hydrate inhibitor composition of claim 11 where the fatty
acid of the lubricity agent is derived from naturally-occurring
fats, naturally-occurring oils, oligomers of naturally-occurring
fats, oligomers of naturally-occurring oils, and combinations
thereof.
13. The hydrate inhibitor composition of claim 11 where the fatty
acid is tall oil fatty acid (TOFA).
14. The hydrate inhibitor composition of claim 11 where the amount
of lubricity agent in the hydrate inhibitor composition ranges from
about 100 ppm to about 500 ppm.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional from U.S. patent
application Ser. No. 13/671,374 filed Nov. 7, 2012, issued ______
as U.S. Pat. No. ______, which in turn claims the benefit of U.S.
Provisional Patent Application Ser. No. 61/561,010 filed Nov. 17,
2011, all of which are incorporated herein by reference in their
entireties.
TECHNICAL FIELD
[0002] The present invention relates to pumping hydrate inhibitors,
and more particularly relates in one non-limiting embodiment to
lubricity agents used to increase the efficiency of pumping hydrate
inhibitors.
TECHNICAL BACKGROUND
[0003] A number of hydrocarbons, especially lower-boiling light
hydrocarbons, in subterranean formation fluids or natural gas are
known to form hydrates in conjunction with the water present in the
system under a variety of conditions--particularly at a combination
of low temperature and high pressure (pressure and temperature are
system-specific for the formation of gas hydrates). The hydrates
usually exist in solid forms that are essentially insoluble in the
fluid itself. As a result, any solids in a subterranean formation
or natural gas fluid are at least a nuisance for production,
handling and transport of these fluids. It is not uncommon for
hydrate solids (or crystals) to cause plugging and/or blockage of
pipelines or transfer lines or other conduits, valves and/or safety
devices and/or other equipment, resulting in shutdown, loss of
production and risk of explosion or unintended release of
hydrocarbons into the environment either on land or off-shore.
Accordingly, hydrocarbon hydrates have been of substantial interest
as well as concern to many industries, particularly the petroleum
and natural gas industries.
[0004] Hydrocarbon hydrates are clathrates, and are also referred
to as inclusion compounds. Clathrates are cage structures formed
between a host molecule and a guest molecule. A hydrocarbon hydrate
generally is composed of crystals formed by water host molecules
surrounding the hydrocarbon guest molecules. The smaller or
lower-boiling hydrocarbon molecules, particularly C.sub.1 (methane)
to C.sub.4 hydrocarbons and their mixtures, are more problematic
because it is believed that their hydrate or clathrate crystals are
easier to form. For instance, it is possible for ethane to form
hydrates at as high as 4.degree. C. at a pressure of about 1 MPa.
If the pressure is about 3 MPa, ethane hydrates can form at as high
a temperature as 14.degree. C. Even certain non-hydrocarbons such
as carbon dioxide, nitrogen and hydrogen sulfide are known to form
hydrates under the proper conditions.
[0005] There are two broad techniques used to overcome or control
the hydrocarbon hydrate problems, namely the use of thermodynamic
inhibitors and Low Dosage Hydrate Inhibitors (LDHIs). LDHIs are
referred to as such due to the low volume required to treat
production streams when compared to thermodynamic inhibitors. For
the thermodynamic approach, there are a number of reported or
attempted methods, including water removal, increasing temperature,
decreasing pressure, addition of "antifreeze" to the fluid and/or a
combination of these. The types of "antifreeze" additives or
thermodynamic hydrate inhibitors (THIs) include, but are not
necessarily limited to methanol, ethanol, monoethylene glycol
(MEG), triethylene glycol (TEG), and combinations thereof. The LDHI
approach is further split into two areas, Anti-agglomerants (AAs)
and kinetic hydrate inhibitors (KHIs). AAs prevent smaller
hydrocarbon hydrate crystals from agglomerating into larger ones
and allow a mass of hydrates, sometimes referred to as a hydrate
slurry, to be transported along the conduit. KHIs however inhibit,
retard and/or prevent initial hydrocarbon hydrate crystal
nucleation; and/or crystal growth. Thermodynamic and kinetic
hydrate control methods may be used in conjunction.
[0006] Kinetic efforts to control hydrates have included the use of
different materials as inhibitors. For instance, onium compounds
with at least four carbon substituents are used to inhibit the
plugging of conduits by gas hydrates. Additives such as polymers
with lactam rings have also been employed to control clathrate
hydrates in fluid systems. LDHIs are relatively expensive
materials, and it is always advantageous to determine ways of
lowering the usage levels of these hydrate inhibitors while
maintaining effective hydrate inhibition.
[0007] In oilfield production applications, especially offshore
applications, it is common practice to pump thermodynamic
inhibitors or a combination of low dose hydrate inhibitors and
thermodynamic inhibitors such as methanol or ethanol subsea to
inhibit the formation of natural gas hydrates plugs. Compositions
containing thermodynamic inhibitors such as methanol and/or ethanol
have poor inherent lubricity properties, which mean they provide
very little boundary lubrication to moving parts within the
injection pumping systems that are under load. These moving parts
can comprise the ball valves in check valves or the pump packing
seals.
[0008] Poor lubrication may cause general wear fatigue of pump
moving parts and can lead to a relatively minor problem such as
reduced pumping efficiency to a worst case scenario of catastrophic
pump failure. These pump failures can be costly not only in terms
of pump replacement but also in terms of a lack of flow assurance
which can result in a shut-in of production and costs associated
with deferred production. In some hydrate inhibitor applications,
lubricant oil is injected into the hydrate inhibitor formulation to
help reduce pump wear. However, conventional lubricant oil is not
very soluble in compositions containing alcohols such as methanol
or ethanol and it does not perform very well at the low
concentrations required to keep it soluble. Currently no commercial
products exist for reducing friction and the associated wear in
hydrate inhibitor formulations that can contain methanol and/or
ethanol. Thus, there exists a need for an effective specialty
chemical additive that can either be injected stand-alone or
blended into the hydrate inhibitor formulation as a package.
[0009] It would be desirable in the art of pumping a hydrate
inhibitor composition to provide compositions and methods for
pumping such compositions so that pumping efficiency and the wear
on moving parts may be improved.
SUMMARY
[0010] There is provided, in one non-limiting form, a method of
pumping a hydrate inhibitor composition, where the method comprises
adding to the hydrate inhibitor composition an effective amount to
increase lubricity of at least one lubricity agent that includes,
but is not necessarily limited to, at least one C1-C36 fatty acid,
at least one derivative of a C1-C36 carboxylic fatty acid and
combinations thereof. The method additionally comprises pumping the
hydrate inhibitor composition containing the lubricity agent.
[0011] There is also provided in an alternative non-restrictive
embodiment, a hydrate inhibitor composition having at least one
hydrate inhibitor and an effective amount to increase lubricity of
the hydrate inhibitor composition of at least one lubricity agent
that includes, but is not necessarily limited to, at least one
C1-C36 carboxylic fatty acid, at least one derivative of a C1-C36
carboxylic fatty acid and combinations thereof. The at least one
lubricity agent is different from the at least one hydrate
inhibitor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a chart of lubricity additive in a hydrate
inhibitor formulation comprised of methanol for a blank and three
lubricity additives indicating average film % and the measured wear
scar diameter (WSD) for each.
DETAILED DESCRIPTION
[0013] It has been discovered that saturated and unsaturated
carboxylic fatty acids, in a non-limiting instance oleic acid, and
derivatives thereof are effective in improving the lubricity of
hydrate inhibitor formulations, thereby reducing the level of wear
on moving parts under a load. These carboxylic fatty acids may be
saturated, unsaturated or blends thereof. These carboxylic fatty
acids can be derived from natural fats and oils or may be
processed-derived acids such as tall oil fatty acids (TOFAs). They
can be monomeric, oligomeric or blends thereof and they can range
in carbon numbers between C1 independently to C36. In an
alternative embodiment, the carbon numbers may range from C10
independently to C18. These carboxylic acids may be straight
chained or branched.
[0014] Alkylamine or alkanolamine salts of these fatty acids are a
suitable derivative in one non-limiting embodiment. Amines that can
be blended into these carboxylic acids include primary, secondary
and tertiary amines which may be alicyclic, suitably a
di-methylcyclohexylamine (DMCHA), heterocyclic, aromatic or
branched. These may be a single amine or a polyamine.
[0015] Other derivatives of the saturated or unsaturated C1-C36
carboxylic fatty acid include, but are not necessarily limited to,
imidazolines, anhydrides, alkyl or alkylphenol esters, and alkyl or
alkanol amides of these fatty acids. In the term "alkylamine", the
term alkyl is defined as a straight, branched or cyclic alkyl of
from 1 independently to about 18 carbon atoms; alternatively from 4
independently to about 8 carbon atoms.
[0016] In the terms "alkyl or alkylphenol ester" and "alkyl or
alkanol amide", the term alkyl is defined as a straight, branched
or cyclic alkyl of from 1 independently to about 54 carbon atoms;
alternatively from 18 independently to about 36 carbon atoms. As
used herein with respect to ranges, the word "independently" means
that any lower threshold may be used together with any upper
threshold to form an acceptable alternative range.
[0017] These carboxylic acids and their amine salts and other
derivatives are soluble in hydrate compositions containing methanol
and/or ethanol and can be added into the formulation separately or
as a blend component at rates between about 25 ppm independently to
about 20,000 ppm; alternatively from about 100 ppm independently to
about 500 ppm.
[0018] The lubricity agents herein may be used in hydrate inhibitor
composition having a hydrate inhibitor selected from the group
consisting of 0.01 to 99.99 vol % of an alcohol selected from the
group consisting of methanol, ethanol, and combinations thereof,
0.01 to 99.99 vol % of a LDHI, which may be AAs and/or KHIs.
Hydrate inhibitors which may be used in the methods and
compositions herein also include the ICE-CHEK.TM. hydrate
inhibitors from BJ Services. The ICE-CHEK.TM. hydrate inhibitors
are made from glycol amines (including, but not necessarily limited
to glycol amines, such as the JEFFAMINE.RTM. polyetheramines
available from Huntsman Corporation, such as JEFFAMINE D-230, D-400
and EDR-148 polyetheramines) in methanol, ethanol or ethylene
glycol. It is expected that adding the C1-C36 to these latter
products would result in the formation of a salt between the acid
and the amines in the ICE-CHEK.TM. hydrate inhibitors.
[0019] It will be appreciated that the hydrate inhibitor
compositions described herein may be used to prevent the formation
of hydrates in the first place and/or at least partially or
completely dissolve or remove hydrate blockages or depositions.
Using THIs to facilitate at least partial dissolution of hydrate
blockages is contemplated along with increasing pump efficiency at
the same time. It will be appreciated that it is not necessary to
completely remove the hydrate blockage or deposit for the method to
be considered successful, only that some of the blockage or deposit
is removed to improve flow.
[0020] It is known to use lubricity agents for fuel compositions
containing alcohols; however the requirement for lubricity in these
systems differs from those where alcohols may be used in hydrate
inhibition systems. Firstly, in the combustion process the alcohol
in the fuel composition is injected during an intake stroke or
suction stroke because the piston moves to the maximum volume
position (downward direction in the cylinder). The inlet valve
opens as a result of piston movement, and under negative pressure
the vaporized fuel mixture enters the combustion chamber. In
contrast, for hydrate inhibitor deployment the formulation
containing either methanol and/or ethanol is under a constant
positive pressure load to overcome the production well pressure and
avoid formulation vaporization.
[0021] Secondly, the additives in fuels are often used to prevent
wear arising from the products of alcohol combustion which include
formaldehyde and formic acid which leads to corrosion of the piston
seals and upper pistons, which is not a concern in pumping hydrate
inhibitor compositions. Thirdly, the temperatures of the
applications are significantly different. In combustion engines the
fuel is heated to high temperatures while in hydrate inhibitor
deployment systems the temperatures can be very low. Pumps that are
deployed subsea may be at temperatures as low as about 4.degree.
C., alternatively in a range from about 50 to about -5.degree. C.,
whereas such pumps could also be employed at moderate temperatures
(about 80-100.degree. C.) if employed in topsides operations.
[0022] Fourthly, the additives contained within the hydrate
formulation are required to be cold stable so that they do not
precipitate during the deployment of the formulation under the cold
conditions experienced by the umbilical at ocean floor temperatures
(about 4.degree. C.); for instance at a range from about 50 to
about -5.degree. C. In summary, one having ordinary skill in the
art knowing of the use of these carboxylic fatty acids in alcohol
fuels would not expect them to be suitable lubricity agents for
hydrate inhibitor compositions given the many differences in the
disparate applications.
[0023] The invention will now be described with reference to
particular Examples which are not intended to limit the invention
but rather simply to illuminate it further.
EXAMPLES 1-12
[0024] Lubricity testing using a High Frequency Reciprocating Rig
(HFRR) demonstrated the efficacy of adding oleic acid to a hydrate
inhibitor formulation containing methanol. By adding 200 ppm of
oleic acid, the average film build up on the metal surface (surface
area) more than doubled from 41% to 90+%, the corresponding
coefficient of friction was lowered by 30% and the resultant wear
scar created by the moving parts of the rig on a steel disc reduced
by as much as 40-45%.
[0025] Table 1 presents a summary of lubricity data for a hydrate
inhibitor composition that is essentially all methanol. In addition
to the blank, a conventional lubricating oil and an oilfield
corrosion inhibitor were used along with poly-glycol, all as
comparisons. Oleic acid (Product A) and an amine (DMCHA) salt of
oleic acid (Product B) gave excellent results; note particularly
Examples 6 and 10, which are plotted along with the blank (Ex. 1)
and 200 ppm lube oil (Ex. 2) in FIG. 1.
TABLE-US-00001 TABLE I Products A and B Methanol Lubricity Summary
Dosage, WSD, Average Average Ex. Additive ppm microns Film %
Friction 1 Blank -- 453 42.14 0.206 2 Lube Oil 200 447 32.32 0.207
3 Polyglycol 200 486 59.3 0.225 4 Oilfield corrosion inhibitor 200
430 25.62 0.162 5 Product A 100 414 49.1 0.21 6 Product A 200 245
92.58 0.136 7 Product A 500 235 97.41 0.136 8 Product A 1000 257
70.17 0.155 9 Product B 200 387 8.9 0.215 10 Product B 350 251
91.35 0.136 11 Product B 500 265 86.34 0.1615 12 Product B 10000
282 68.29 0.151
[0026] It appears that the Average Film result for Example 9 of
8.9% is an outlier compared to the results for the other Examples,
for an unknown reason.
EXAMPLES 13-15
[0027] The use of a corrosion inhibitor effective in ethanol and an
ester-based (monoethylene glycol dimerate) lubricity additive in
diesel fuel was also evaluated. Product A and Product B also
outperformed both of these as well. Compare the data in Table II
with that in Table I.
TABLE-US-00002 TABLE II Comparative Corrosion Inhibitor Products
Lubricity Summary Dosage, WSD, Average Average Ex. Additive ppm
microns Film % Friction 13 Blank -- 453 42.14 0.206 14 Ethanol
corrosion inhibitor 200 420 32.51 0.188 15 Ester-based lubricity
additive 200 401 57.61 0.195
[0028] It is to be understood that the invention is not limited to
the exact details of carboxylic fatty acids, derivatives thereof,
sources thereof, thermodynamic inhibitors, LDHIs, AAs, KHIs, etc.
shown and described, as modifications and equivalents thereof will
be apparent to one skilled in the art. The invention is therefore
to be limited only by the scope of the appended claims. Further,
the specification is to be regarded in an illustrative rather than
a restrictive sense. For example, specific combinations of
carboxylic fatty acids, derivatives thereof, dosages thereof,
hydrate inhibitor compositions, and the like falling within the
described parameters herein, but not specifically identified or
tried in a particular composition method or apparatus, are expected
to be within the scope of this invention.
[0029] The terms "comprises" and "comprising" used in the claims
herein should be interpreted to mean including, but not limited to,
the recited elements.
[0030] The present invention may suitably comprise, consist or
consist essentially of the elements disclosed and may be practiced
in the absence of an element not disclosed. For instance, the
method of pumping a hydrate inhibitor composition may consist of or
consist essentially of adding to the hydrate inhibitor composition
an effective amount to increase lubricity of a lubricity agent
selected from the group consisting of at least one C1-C36
carboxylic fatty acid, an alkylamine salt of a C1-C36 fatty acid,
an alkyl ester of a C1-C36 fatty acid, an alkylphenol ester of a
C1-C36 fatty acid, an alkanolamine salt of a C1-C36 fatty acid, an
imidazoline salt of a C1-C36 fatty acid, an anhydride salt of a
C1-C36 fatty acid, an alkanol amide of a C1-C36 fatty acid, an
alkyl amide of a C1-C36 fatty acid, a polyetheramine salt of a
C1-C36 fatty acid, and combinations thereof; and pumping the
hydrate inhibitor composition containing the lubricity agent. In
another instance, a hydrate inhibitor composition may consist of or
consist essentially of at least one hydrate inhibitor and an
effective amount to increase lubricity of the hydrate inhibitor
composition of at least one lubricity agent selected from the group
consisting of at least one C1-C36 carboxylic fatty acid, an
alkylamine salt of a C1-C36 fatty acid, an alkyl ester of a C1-C36
fatty acid, an alkylphenol ester of a C1-C36 fatty acid, an
alkanolamine salt of a C1-C36 fatty acid, an imidazoline salt of a
C1-C36 fatty acid, an anhydride salt of a C1-C36 fatty acid, an
alkanol amide of a C1-C36 fatty acid, an alkyl amide of a C1-C36
fatty acid, a polyetheramine salt of a C1-C36 fatty acid, and
combinations thereof and combinations thereof. In these
embodiments, the lubricity agent is different from the at least one
hydrate inhibitor.
* * * * *