U.S. patent application number 12/565425 was filed with the patent office on 2011-03-24 for foamers for downhole injection.
Invention is credited to Duy T. Nguyen.
Application Number | 20110071060 12/565425 |
Document ID | / |
Family ID | 43757142 |
Filed Date | 2011-03-24 |
United States Patent
Application |
20110071060 |
Kind Code |
A1 |
Nguyen; Duy T. |
March 24, 2011 |
FOAMERS FOR DOWNHOLE INJECTION
Abstract
This invention relates generally to novel foamer compositions
for treatment of oil and gas wells to enhance production. The
invention provides a method of foaming a fluid. The method includes
introducing into the fluid a foam-forming amount of a composition
comprising at least one long chain fatty acid and at least one
organic solvent. An example of the long chain fatty acid is tall
oil fatty acid and an example of the organic solvent is
ethyleneglycol monobutyl ether.
Inventors: |
Nguyen; Duy T.; (Houston,
TX) |
Family ID: |
43757142 |
Appl. No.: |
12/565425 |
Filed: |
September 23, 2009 |
Current U.S.
Class: |
507/265 |
Current CPC
Class: |
C09K 8/38 20130101; C09K
8/594 20130101; C09K 8/518 20130101; C09K 2208/32 20130101; C09K
8/703 20130101; C09K 8/58 20130101; C09K 8/94 20130101 |
Class at
Publication: |
507/265 |
International
Class: |
C09K 8/64 20060101
C09K008/64 |
Claims
1. A method of foaming a fluid, the method comprising: introducing
into the fluid a foam-forming amount of a composition comprising at
least one long chain fatty acid and at least one organic
solvent.
2. The method of claim 1, wherein the long chain fatty acid is tall
oil fatty acid.
3. The method of claim 1, wherein the organic solvent is selected
from the group consisting of: alcohols, glycols, aliphatic
hydrocarbons, aromatic hydrocarbons, and combinations thereof.
4. The method of claim 1, wherein the organic solvent is
ethyleneglycol monobutyl ether.
5. The method of claim 1, wherein the organic solvent is present in
an amount ranging from about 5 to about 70% by weight actives based
on a total weight of the composition.
6. The method of claim 1, wherein the long chain fatty acid is
dispersed or dissolved in the organic solvent.
7. The method of claim 1, further comprising introducing into the
fluid the foam-forming amount of the foaming composition to the
downhole end of a well as batch addition or continuously.
8. The method of claim 1, further comprising introducing to the
fluid from about 10 ppm to about 100,000 ppm of actives in the
composition to the well, based on volume of the fluid.
9. The method of claim 1, further comprising introducing to the
fluid from about 100 ppm to about 20,000 ppm of actives in the
foaming composition to the well, based on volume of the fluid.
10. The method of claim 1, farther comprising introducing to the
fluid from about 200 ppm to about 10,000 ppm of actives in the
foaming composition to the well, based on volume of the fluid.
11. The method of claim 1, wherein the fluid is oil or gas and
water.
Description
TECHNICAL FIELD
[0001] This invention relates generally to methods of using novel
foamer compositions for treatment of oil and gas wells to enhance
production. More specifically, the invention relates to novel
foamer compositions having a tall oil fatty acid component and an
organic solvent. The invention has particular relevance to foamer
compositions having a tall oil fatty acid component and a glycol
component.
BACKGROUND
[0002] Declining reservoir pressure in natural gas wells may lead
to gas production decreases. The typical cause of this decrease is
liquid loading that occurs when water and condensate enter the
bottom of the well. Foaming agents (sometimes referred to as
"foamers") are frequently used to aid in the unloading of water and
condensate accumulated in the wellbore, thereby increasing
production from a loaded well. Such agents are generally applied
either by batch treatments or continuous applications via injecting
down a capillary string or via the casing/tubing annulus. Foamers
function by reducing the surface tension and fluid density in the
wellbore, and may also be used in conjunction with a lift gas to
enhance oil recovery from oil wells.
[0003] U.S. Pat. App. Pub. No. 2006/0128990 teaches a method of
treating a gas well comprising a chloride-free amphoteric
surfactant. U.S. Pat. No. 7,122,509 discloses a method of preparing
a foamer composition having an anionic surfactant and a
neutralizing amine. In U.S. Pat. App. Pub. 2005/0137114 an aqueous
foaming composition comprising an anionic surfactant, a cationic
surfactant, and a zwitterionic compound is disclosed. PCT App. Pub.
No. WO 02/092963 and U.S. Pat. App. Pub. No. 2007/0079963 disclose
methods for recovering oil from a gas-lifted oil well using a lift
gas and a foaming surfactant which consists of nonionic
surfactants, anionic surfactants, betaines, and siloxanes.
[0004] While such foamers represent a significant contribution to
the art of unloading fluids in oil and gas wells, there still
remains a need for improved foamers and methods of using improved
foamers. It is thus an objective of this invention to provide a
cost-effective foamer for unloading oil, water, or mixtures thereof
from oil and/or gas wells. Such improved foamers would also ideally
be compatible with anti-corrosive and anti-scale agents.
SUMMARY
[0005] This invention provides a method of foaming a fluid. In a
preferred aspect, the method includes introducing into the fluid a
foam-forming amount of a composition comprising at least one long
chain fatty acid and at least one organic solvent. In preferential
embodiments, the long chain fatty acid is preferably tall oil fatty
acid and the organic solvent is preferably ethyleneglycol monobutyl
ether.
[0006] It is an advantage of the invention to provide novel foaming
agents for downhole injection in oil and gas wells.
[0007] It is a further advantage of the invention to provide an
efficient method of recovering oil from a gas-lifted oil well
penetrating a subterranean oil-bearing formation.
[0008] Another advantage of the invention is to provide an
efficient method to remove hydrocarbon fluids from a gas-producing
well.
[0009] Additional features and advantages are described herein, and
will be apparent from, the following Detailed Description and
Examples.
DETAILED DESCRIPTION
[0010] The method of using the foaming compositions of this
invention have been shown to be effective for recovering natural
gas from a gas well and recovering crude oil from a gas-lifted oil
well penetrating a subterranean oil-bearing formation. That is, the
foaming agents of the present invention effectively remove
hydrocarbon and/or water or mixtures thereof from the wells. The
effective amount of active ingredient in a formulation required to
sufficiently foam varies with the system in which it is used.
Methods for monitoring foaming rates in different systems are well
known to those skilled in the art and may be used to decide the
effective amount of active ingredient required in a particular
situation. The described compounds may be used to impart the
property of foaming to a composition for use in an oil or gas field
application.
[0011] The foamers of the invention can be applied by batch
treatments or continuous applications via the casing/tubing annulus
or via capillary strings and are typically introduced into the
downhole end of a well. A batch treatment involves the application
of a single volume of foamer to the well, as opposed to a smaller
volume applied continuously for the case of a continuous
application. The next batch is applied after a period of time when
the foamer starts to lose its effectiveness.
[0012] The described foaming compositions are particularly
effective for unloading fluids (oil and/or water) from oil and gas
wells under a variety of conditions. These compounds/compositions
may be used in wells in which oil cuts in the field can range from
about 0% (oil field) to 100% (refinery) oil, while the nature of
the water can range from 0 to 300,000 ppm TDS (total dissolved
solids). In addition, the bottom hole temperature can be between
60.degree. F. and 400.degree. F. In a preferred method, the
described foamers can be applied by batch treatments or
continuously via the casing/tubing annulus or via capillary
strings. Batch treatment typically involves the application of a
single volume of foamer to the well, where a subsequent batch is
applied when the foamer begins to lose its effectiveness. In a
typical continuous application, in contrast, a smaller volume is
applied continuously.
[0013] In an embodiment, a synergistic foaming agent is formed by
mixing one or more long chain fatty acids with one or more organic
solvents. A preferred composition is prepared by blending by
blending a TOFA with EGMBE. According to alternative embodiments of
the invention, the organic solvent is present in an amount from
about 5 to about 70% by weight of actives based on the total weight
of the mixture. Mixtures of TOFA and other long chain fatty acids
are used in other embodiments of the invention as well as mixture
of EGMBE and other organic solvents. The effectiveness of the
foaming agent formulation of this invention can generate stable
foams levels from about 10 ppm to about 100,000 ppm of actives. A
more preferred range is about 100 ppm to about 20,000 ppm of
actives. Most preferably, the range is from about 200 ppm to about
10,000 ppm of actives. Each dosage is based on total volume of
fluid.
[0014] "Organic solvent" generally refers to one or more organic
solvents or a mixture of water and organic solvent(s). Examples of
suitable solvents are alcohols such as methanol, ethanol,
isopropanol, isobutanol, secondary butanol; glycols such as
ethylene glycol, and ethylene glycol monobutyl ether ("EGMBE"), and
the like; and aliphatic and aromatic hydrocarbons including heavy
aromatic naphtha. The selection of the solvent system may be made
empirically based on the characteristics of the system being
treated. The preferred organic solvent is EGMBE.
[0015] "Long chain fatty acids" refers to fatty acids of the type
R.sub.1CO.sub.2H. Representative long chain fatty acids include
caprylic acid; nonanoic acid; capric acid; undecanoic acid; lauric
acid; tridecanoic acid; myristic acid; palmitoleic acid; tall oil
fatty acid ("TOFA"), such a mixture of oleic, linoleic and
linolenic acids; stearic acid; palmitic acid; arachidic acid;
arachidonic acid; oleic acid; 9,11,13-octadecatrienoic acid;
5,8,11,14-eicosatetraenoic acid; eicosenoic acid; heneicosenoic
acid; erucic acid; heneicosanoic acid; behenic acid;
3-methylhexadecanoic acid; 7-methylhexadecanoic acid;
13-methylhexadecanoic acid; 14-methyl-11-eicosenoic acid; the like;
and mixtures thereof.
[0016] The preferred long chain fatty acid is TOFA, which in an
embodiment refers to a distilled product derived from trees and
which consists of a mixture of fatty acids, C.sub.17H.sub.31-35
COON with a CAS No. 61790-12-3. It is a mixture of oleic acid as a
major component, linoleic acid and saturated fatty acids. For
purposes of this invention the radical obtained therefrom will be
identified as heptadecenyl. In another embodiment, TOFA refers to
tall oil fatty acid stock and typically includes about 1% palmitic
acid; about 2% stearic acid; about 48% oleic acid; about 35%
linoleic acid; about 7% conjugated linoleic acid
(CH.sub.3(CH.sub.2).sub.XCH.dbd.CHCH.dbd.CH(CH.sub.2).sub.YCOOH,
where x is generally 4 or 5, y is usually 7 or 8, and X+Y is 12);
about 4% other acids, such as 5,9,12-octadecatrienoic acid,
linolenic acid, 5,11,14-eicosatrenoic acid,
cis,cis-5,9-octadecadienoic acid, eicosadienoic acid, elaidic acid,
cis-11 octadecanoic acid, and C-20, C-22, C-24 saturated acids; and
about 2% unsaponifiable matter. In other embodiments, TOFA includes
any suitable tall oil fatty acid or mixture known in the art or
equivalents thereof.
[0017] It should be appreciated that the described compounds may be
used alone or in combination with other compounds to further
increase the effect and delivery of the products. Typical
combinations include pour point depressants and/or surfactants.
Examples of suitable pour point depressants are C.sub.1 to C.sub.3
linear or branched alcohols, ethylene, and propylene glycol.
Examples of suitable surfactants are nonionic surfactants, such as
alkoxylated alcohols, carboxylic acids or ethers, alkyl
ethoxylates, and sorbitan derivatives; anionic surfactants, such as
fatty carboxylates, alkyl phosphates, alkyl sulfonates, and alkyl
sulfates; cationic surfactants, such as mono- and di-alkyl
quaternary amines; amphoteric surfactants, such as alkyl betaines,
alkylamido propyl betaines, alklyampho acetates, and
alkylamidopropyl hydroxysultaines. Moreover, the described foamers
may also be used in conjunction with other foamers, such as those
disclosed in U.S. patent application Ser. No. 11/940,777,
"Imidazoline-Based Heterocyclic Foamers for Downhole Injection" and
any other suitable foamers.
[0018] The described foamers or foaming agents of this invention
have been shown to be effective for penetrating subterranean
oil-bearing or gas-bearing formations to recover natural gas from a
gas well or recover crude oil from a gas-lifted oil well. Exemplary
gas-lift methods for producing oil are disclosed in U.S. Pat. No.
5,871,048 and U.S. Patent Application No. 2004-0177968 A1. In other
words, the foaming agents of the invention are effective at aiding
and making more efficient removal of hydrocarbon and/or water or
mixtures thereof from wells. It should be appreciated that in some
embodiments other corrosion inhibitors, scale inhibitors, and/or
biocides may be used in conjunction with or in formulations
including the foamers of this invention.
[0019] Representative corrosion inhibitors include amidoamines,
quaternary amines, amides, phosphate esters, other suitable
corrosion inhibitors, and combinations thereof. Representative
scale inhibitors include polyphosphates, polyphosphonates, other
suitable scale inhibitors, and combinations thereof. Exemplary
corrosion inhibitors are disclosed in U.S. patent application Ser.
No. 11/763,006, "Mono and Bis-Ester Derivatives of Pyridinium and
Quinolinium Compounds as Environmentally Friendly Corrosion
Inhibitors" or any other suitable corrosion inhibitor. The
composition may also include one or more suitable solvents
including, but not limited to water, monoethylene glycol, ethylene
glycol, ethylene glycol monobutyl ether, methanol, isopropanol, the
like, derivatives thereof, and combinations thereof.
[0020] Even though this disclosure is directed primarily to oil and
gas recovery applications, it is contemplated that the composition
of the invention may also be used in other applications. For
example, the composition may be used as a deposit control agent or
cleaner to remove deposits (e.g., hydrocarbonaceous deposits) from
wells and/or pipelines. "Hydrocarbonaceous deposit" refers
generally to any deposit including at least one hydrocarbon
constituent and forming on the inner surface of flowlines,
pipelines, injection lines, wellbore surfaces, storage tanks,
process equipment, vessels, the like, and other components in oil
and gas applications. Such deposits also include "schmoo," which
refers to a solid, paste-like, or sludge-like substance that
adheres to almost any surface with which it comes in contact and is
particularly difficult to remove. Deposits contributing to schmoo
may include, for example, sand, clays, sulfur, naphthenic acid
salts, corrosion byproducts, biomass, and other hydrocarbonaceous
materials bound together with oil. The compositions of this
invention may be used in conjunction with other deposit control
agents, such as those disclosed in U.S. patent application Ser. No.
11/952,211, "Environmentally Friendly Bis-Quaternary Compounds for
Inhibiting Corrosion and Removing Hydrocarbonaceous Deposits in Oil
and Gas Applications."
Example
[0021] The foregoing may be better understood by reference to the
following example, which is intended for illustrative purposes and
is not intended to limit the scope of the invention.
[0022] This example illustrates the effectiveness of the foamer
composition of the invention. In a preferred method of preparation,
the foaming composition of the invention was prepared by mixing 70
grams of TOFA with 5% rosin with 30 grams of EGMBE at room
temperature. A homogeneous solution was observed. The product was
identified as Product 1. TOFA with 5% rosin in the absence of EGMBE
was identified as Product 2. TOFA containing 1% rosin and zero
EGMBE was identified as Product 3.
[0023] The table below displays the results when a foaming agent
was added to a mixture of hydrocarbon condensate received from the
field and brine (10.2% NaCl and 3.7% CaCl.sub.2.2H.sub.2O) in a
ratio of 9 to 1, respectively. The condensate-to-brine ratios were
90/10 (vol/vol) for all tests. Cocoamidopropyl betaine (C. Betaine
in the table below), a conventional foaming agent, was also tested
as a control. The test cell included a nitrogen supply; a jacketed
1,000 ml graduated cylinder with a glass frit on the bottom for gas
flow; a flow meter; a temperature-controlled water bath; a
container for collecting unloaded liquid; a condenser for
transporting the liquid from a cylinder to another container; and a
balance connected to a computer for recording real-time
measurements. The gas flow rate was held constant at 15 SCFH.
[0024] The weight percent liquid unloading was calculated by
dividing the weight of the collected liquid in the container at 5
min (i.e., the amount overflowed) by the initial weight placed in
the cylinder times 100. The weight percent of the liquid removed
(i.e., percent unloading) was then calculated from 100 grams of
fluid. It can be seen that Products 1, 2, and 3 of the present
invention are superior to the conventional foamer. It can also be
seen that addition of EGMBE increases the liquid unloading
efficiency (Product 1 vs. Product 2).
TABLE-US-00001 Foamer Percent Product Actives Unloading C. Betaine
1% 0 Product 1 7,000 ppm 62 Product 2 1% 45 Product 3 1% 35
[0025] All of the compositions and methods disclosed and claimed
herein can be made and executed without undue experimentation in
light of the present disclosure. While this invention may be
embodied in many different forms, there are described in detail
herein specific preferred embodiments of the invention. The present
disclosure is an exemplification of the principles of the invention
and is not intended to limit the invention to the particular
embodiments illustrated.
[0026] Any ranges given either in absolute terms or in approximate
terms are intended to encompass both, and any definitions used
herein are intended to be clarifying and not limiting.
Notwithstanding that the numerical ranges and parameters setting
forth the broad scope of the invention are approximations, the
numerical values set forth in the specific examples are reported as
precisely as possible. Any numerical value, however, inherently
contains certain errors necessarily resulting from the standard
deviation found in their respective testing measurements. Moreover,
all ranges disclosed herein are to be understood to encompass any
and all subranges (including all fractional and whole values)
subsumed therein.
[0027] Furthermore, the invention encompasses any and all possible
combinations of some or all of the various embodiments described
herein. Any and all patents, patent applications, scientific
papers, and other references cited in this application, as well as
any references cited therein and parent or continuation patents or
patent applications, are hereby incorporated by reference in their
entirety. It should also be understood that various changes and
modifications to the presently preferred embodiments described
herein will be apparent to those skilled in the art. Such changes
and modifications can be made without departing from the spirit and
scope of the invention and without diminishing its, intended
advantages. It is therefore intended that such changes and
modifications, be covered by the appended claims.
[0028] The claimed invention is:
* * * * *