U.S. patent application number 11/715566 was filed with the patent office on 2008-09-11 for gelled emulsions and methods of using the same.
This patent application is currently assigned to BJ Services Company. Invention is credited to John Roland Delorey, Brad Rieb.
Application Number | 20080217012 11/715566 |
Document ID | / |
Family ID | 39740479 |
Filed Date | 2008-09-11 |
United States Patent
Application |
20080217012 |
Kind Code |
A1 |
Delorey; John Roland ; et
al. |
September 11, 2008 |
Gelled emulsions and methods of using the same
Abstract
Gelled emulsions contain (i.) an external phase of an aqueous
water-soluble solvent solution, polymeric viscosifying agent and,
optionally, an oxidative and/or acidic breaker; and (ii.) an
internal phase of a dispersed organic fluid. The aqueous
water-soluble solvent solution constitutes between from about 15 to
about 50 volume percent of the gelled emulsion and the dispersed
organic fluid is presented in the gelled emulsion in amounts
ranging from about 50 to about 85 volume percent. The gelled
emulsions are useful in a variety of applications including, but
not limited to, oil field, pipeline and processing facility
applications.
Inventors: |
Delorey; John Roland;
(Calgary, CA) ; Rieb; Brad; (Calgory, CA) |
Correspondence
Address: |
JONES & SMITH , LLP
2777 ALLEN PARKWAY, SUITE 800
HOUSTON
TX
77019
US
|
Assignee: |
BJ Services Company
|
Family ID: |
39740479 |
Appl. No.: |
11/715566 |
Filed: |
March 8, 2007 |
Current U.S.
Class: |
166/300 ;
166/244.1 |
Current CPC
Class: |
C09K 8/703 20130101;
C09K 2208/26 20130101 |
Class at
Publication: |
166/300 ;
166/244.1 |
International
Class: |
E21B 43/16 20060101
E21B043/16 |
Claims
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33. A method of stimulating a subterranean formation which
comprises introducing into the formation. an emulsion comprising:
(a) a gelled external phase comprising (i.) an aqueous
water-soluble solvent solution and (ii.) a polymeric viscosifying
agent; (b) an internal phase of an organic fluid; (c) an
emulsifying agent; and (d) optionally, an oxidative and/or acidic
breaker wherein the emulsion is substantially free of
phosphorous.
34. The method of claim 33, wherein the emulsion is prepared on the
fly.
35. The method of claim 33, wherein the emulsion contains no
phosphorous.
36. The method of claim 33, wherein the emulsion further comprises
a proppant.
37. The method of claim 33, wherein the emulsion further comprises
a foaming or gasifying agent.
38. The method of claim 37, wherein the foaming or gasifying agent
is carbon dioxide or nitrogen.
39. The method of claim 33, wherein the organic solvent of the
organic solvent solution is selected from the group consisting of a
C.sub.1-C.sub.4 alcohol, ethylene glycol, propylene glycol,
acetone, methylene sulfonic acid, acetic acid, formic acid and
hydroxy acetic acid and mixtures thereof.
40. The method of claim 39, wherein the organic solvent is a
C.sub.1-C.sub.4 alcohol.
41. The method of claim 40, wherein the C.sub.1-C.sub.4 alcohol is
methanol, ethanol or isopropanol.
42. The method of claim 41, wherein the C.sub.1-C.sub.4 alcohol is
methanol.
43. The method of claim 33, wherein the emulsifying agent is at
least one member selected from the group consisting of: (a)
alkoxylated non-ionic emulsifiers having a lipophilic portion
comprising a C.sub.12-C.sub.36 alkyl, dialkyl or alkylaryl and a
hydrophilic portion having 20 to 150 moles of polyalkylene oxide;
(b) an anionic, cationic or zwitterionic/amphoteric emulsifier
having a lipophilic portion comprising a lipophilic portion
comprising a C.sub.12-C.sub.22 alkyl, dialkyl or alkylaryl group
and a hydrophilic portion having 10 to 80 moles of polyalkylene
oxide; (c) an ethylene oxide/propylene oxide block copolymer
comprising between from about 10 to about 50 moles of propylene
oxide and from about 20 to about 150 moles of ethylene oxide; and
(d) polyoxyalkylene sorbitan fatty acid esters.
44. The method of claim 33, wherein the emulsion contains an
oxidative and/or acidic breaker and further wherein the oxidative
and/or acidic breaker is selected from the group consisting of
hydrochloric acid, formic acid, sulfamic acid, sodium bisulfate, an
alkaline earth peroxide, an encapsulated persulfate, a catalyzed
organic peroxide and a hydrochlorite bleach.
45. The method of claim 33, wherein the organic fluid is at least
one member selected from the group consisting of diesel, kerosene,
gasoline, reformate, naphthalene, condensate, crude oil, mineral
oil, vegetable oil, lubricating oil, synthetic oil, animal oil, an
aliphatic, alicyclic or aromatic hydrocarbon, alkene, alkadienes
and ester.
46. The method of claim 45, wherein the organic fluid is selected
from the group consisting of propane, n-butane, isobutane,
n-hexane, n-octane, n-decane, n-tridecane, cyclohexane, benzene,
toluene, xylene, ethylbenzene, naphthalene, a C.sub.8-C.sub.15
alkane, an alkene and an alkadiene.
47. The method of claim 33, wherein the polymeric viscosifying
agent is selected from the group consisting of polysaccharides,
polysaccharide derivatives containing monosaccharides,
polyacrylates, polyacrylamides, acrylamide methyl propane sulfonic
acid copolymers, polyvinyl alcohol, polyvinyl pyrrolidone, maleic
anhydride methyl vinyl ether copolymers and polyethylene oxide.
48. The method of claim 47, wherein the polymeric viscosifying
agent is a polysaccharide or a derivatized polysaccharide of sugars
selected from the group consisting of glucose, galactose, mannose,
xylose, arabinose, fructose, guar gum derivatives, xanthan gum and
a starch derivative.
49. The method of claim 48, wherein the polymeric viscosifying
agent is a guar derivative.
50. The method of claim 33, wherein the polymeric viscosifying
agent is selected from the group consisting of hydroxypropyl guar,
hydroxyethyl guar, carboxymethyl hydroxypropyl guar, carboxymethyl
hydroxyethyl cellulose and hydroxypropyl cellulose.
51. The method of claim 49, wherein the guar derivative is a
hydroxyalkylated guar or modified hydroxyalkylated guar.
52. The method of claim 51, wherein the guar derivative is
hydroxypropyl guar.
53. The method of claim 33, wherein the HLB of the emulsifying
agent is between from about 10 to about 20.
54. The method of claim 53, wherein the HLB of the emulsifying
agent is between from about 16 to about 18.
55. The method of claim 33, wherein the relative solubility number
of the emulsifying agent is in excess in 10.
56. The method of claim 55, wherein the relative solubility number
of the emulsifying agent is between from about 13 to about 17.
57. A method of stimulating a subterranean formation which
comprises introducing into the formation a gelled emulsion
comprising: (a) from about 15 to about 50 volume percent of a blend
of a C.sub.1-C.sub.4 alkanol and water; (b) from about 50 to about
85 volume percent of a dispersed organic fluid; (c) a polymeric
viscosifying agent; (d) an emulsifying agent; and (e) optionally,
an oxidative and/or acidic breaker wherein the emulsion is
substantially free of phosphorous.
58. The method of claim 57, wherein the blend of C.sub.1-C.sub.4
alkanol and water contains between from about 15 to about 80 volume
percent of alkanol and the remainder water.
59. The method of claim 57, wherein the alkanol is methanol.
60. The method of claim 57, wherein the dispersed organic fluid is
hydroxypropyl guar having a molar substitution between from about
0.80 to about 1.20.
61. The method of claim 57, wherein the emulsifying agent is at
least one member selected from the group consisting of: (a)
alkoxylated non-ionic emulsifiers having a lipophilic portion
comprising a C.sub.12-C.sub.36 alkyl, dialkyl or alkylaryl and a
hydrophilic portion having 20 to 150 moles of polyalkylene oxide;
(b) an anionic, cationic or zwitterionic/amphoteric emulsifier
having a lipophilic portion comprising a lipophilic portion
comprising a C.sub.12-C.sub.22 alkyl, dialkyl or alkylaryl group
and a hydrophilic portion having 10 to 80 moles of polyalkylene
oxide; (c) an ethylene oxide/propylene oxide block copolymer
comprising between from about 10 to about 50 moles of propylene
oxide and from about 20 to about 150 moles of ethylene oxide; and
(d) polyoxyalkylene sorbitan fatty acid esters.
62. A method of stimulating a subterranean formation which
comprises introducing into the formation an emulsion comprising:
(a) an external phase comprising a gelled product of a (i)
C.sub.1-C.sub.4 alkanol and water; and (ii) a viscosifying polymer;
(b) an internal phase of a dispersed organic fluid; and (c) an
emulsifying agent.
63. The method of claim 62, wherein the external phase further
comprises an oxidative and/or acidic breaker.
64. The method of claim 62, wherein the internal phase further
comprises carbon dioxide.
Description
FIELD OF THE INVENTION
[0001] The invention relates to gelled emulsions which contain an
aqueous water-soluble solvent solution. The gelled emulsions are
essentially phosphate-free. The invention further relates to
methods of using such gelled emulsions.
BACKGROUND OF THE INVENTION
[0002] Stimulation techniques, such as hydraulic fracturing, used
in the treatment of oil and gas wells improve productivity of the
treated well. In hydraulic fracturing, a fluid is injected down the
wellbore and into the productive formation at a sufficient rate and
pressure such that the formation rock fractures from the induced
stresses. A proppant is added to the fluid and is carried into the
formation fracture. The proppant prevents closure of the fracture
when hydraulic pressures are released, thereby leaving a conductive
flow channel from the wellbore deep into the rock matrix.
[0003] Traditionally the fluid used for the purpose of hydraulic
fracturing has been oil, water, or an emulsion of these two
liquids. An efficient fracturing fluid should possess good proppant
transport characteristics. Such characteristics are dependent on
the viscosity of the fluid. Generally, the viscosity should be high
in order to achieve wider and larger fractures. High viscosity is
further generally desirable for more efficient transport of
proppant into the fractured formation. A wide range of additives
may be used to enhance the rheological properties and/or the
chemical properties of the fluid. Such additives include
viscosifiers, friction reducing agents, surface active agents,
fluid loss control additives and the like. After the fracturing
treatment is complete, it is desirable to lower the viscosity of
the fluid, so that it can be pumped back out of the well without
carrying entrained proppant.
[0004] Fracturing fluids, especially those used in the stimulation
of gas wells, often contain aqueous methanol, either by itself or
in conjunction with a foaming agent (surfactant) and a gas, such as
carbon dioxide or nitrogen. The use of methanol or other
water-soluble solvents in stimulation fluids is desirable for
several reasons. Being non-aqueous, such solvents minimize the
tendency of the clay-filled reservoir porosity to swell and
migrate. They also impart a low surface and interfacial tension to
water-based fluids, thereby reducing the pressure required for
initial cleanup. In the case of methanol, it is also very volatile
and will therefore evaporate even in the presence of water
saturated gases. The use of methanol with liquid carbon dioxide is
particularly beneficial because of its low freeze point.
[0005] Some efforts have therefore been undertaken to develop
emulsions which use anhydrous fluids. For instance, U.S. Pat. No.
4,554,082 discloses a fracturing fluid containing liquefied carbon
dioxide, anhydrous glycol/hydrocarbon and a low HLB surfactant to
form a liquid-liquid emulsion. Glycol, however, is more costly than
methanol and exhibits lower volatility. The disclosed emulsions are
further undesirable since, at elevated temperatures and pressures,
hydrocarbons (such as kerosene and diesel fuel) become miscible and
a low viscosity, single phase liquid results.
[0006] U.S. Pat. No. 6,838,418 discloses a fracturing emulsion
fluid containing carbon dioxide as an internal phase and an
external phase containing a high percentage of methanol and water,
an emulsifier and a synthetic polymer for thickening the emulsion.
The emulsion does not contain a hydrocarbon phase which is
considered commercially desirable since carbon dioxide is not
always available and since hydrocarbons are generally cheaper and
easier to recover.
[0007] Traditionally, hydrocarbon based fluids, such as those
disclosed in U.S. Pat. Nos. 5,514,645, 5,190,675 and 6,149,693, are
gelled with phosphate esters and have particular applicability in
the fracturing of deep gas wells. The absence of high molecular
weight polymers and the inherent low interfacial tension between
the hydrocarbon and the high pressure reservoir gas provides highly
effective fluid recovery. Concerns have arisen, however, regarding
residual phosphorous compounds (which may remain in the crude and
cause refinery upsets) as well as contamination of refined
petroleum products.
[0008] While non-phosphate-based hydrocarbon gellants have been
developed, such as those disclosed in U.S. Pat. No. 6,849,581, they
are often slow to gel at low temperature. Other non-phosphate-based
hydrocarbon gellants are too expensive to be commercially viable.
Further, the gelation rates and stability of many of the
non-phosphate-based hydrocarbon gels of the prior art are severely
affected by contaminants such as, for example, water. This further
makes them commercially undesirable.
[0009] Alternatives continue to be sought for phosphorous-free
gelled fluids which provide the benefits of phosphate ester gelled
hydrocarbons.
SUMMARY OF THE INVENTION
[0010] The invention relates to gelled emulsions which are
essentially phosphorous-free. The gelled emulsion contains an
aqueous water-soluble solvent solution and a dispersed hydrocarbon
or organic fluid. In addition, the gelled emulsion contains a
polymeric viscosifying agent, emulsifying agent and, optionally, an
oxidative or acidic breaker (or both oxidizer and acidic breaker).
The gelled emulsion further may contain a dispersed gaseous
component, such as carbon dioxide or nitrogen.
[0011] The external phase of the emulsion contains the aqueous
water-soluble solvent solution and the polymeric viscosifying
agent, emulsifying agent and, optionally, oxidative and/or acidic
breaker. The internal phase contains the dispersed
hydrocarbon/organic fluid. The internal phase further may contain
the optional gaseous component(s). The emulsifying agent serves as
the coalescence barrier to the external and internal phases.
[0012] Additives and mixing methodology may be employed in order to
delay the hydration of the polymeric viscosifying agent. As such,
the initial viscosity of the gelled emulsion may be minimized; the
viscosity of the emulsion being allowed to increase over time.
This, in turn, minimizes pumping friction pressure.
[0013] The aqueous water-soluble solvent solution may consist of an
organic solvent that reduces the interfacial tension of the water.
The solvent is preferably volatile in the producing reservoir gas.
Although the water-soluble solvent is typically a C.sub.1-C.sub.4
alcohol, preferably methanol, other water-soluble solvents may also
be used such as ethylene glycol, propylene glycol, acetone,
methylene sulfonic acid, acetic acid, formic acid and hydroxy
acetic acid as well as mixtures thereof.
[0014] The aqueous water-soluble solvent solution typically
constitutes between from about 15 to about 50 volume percent of the
gelled emulsion. The dispersed organic fluid is present in the
gelled emulsion in amounts ranging from about 50 to about 85 volume
percent.
[0015] The dispersed organic fluid is preferably at least one of
diesel, gasoline, kerosene, reformate, naphthalene, xylene,
toluene, mineral oil, light mineral oil, condensate, crude oil,
lubricating oils, or mixtures thereof. In some applications other
organic fluids with limited water solubility may be used.
[0016] Suitable polymeric viscosifying agents include those having
one or more hydroxyl, carboxyl, sulfate, sulfonate, amino or amide
functional groups as well as polysaccharides and polysaccharide
derivatives such as guar gum derivatives.
[0017] Suitable emulsifying agents are those which ensure that the
aqueous water-soluble solvent solution remains the external phase
of the emulsion as the dispersed phase content is increased and
that the stability of the gelled emulsion is maintained at
reservoir temperatures for at least 10 minutes under static
conditions.
[0018] The gelled emulsions have particular applicability in the
fracturing of gas wells.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more fully understand the drawings referred to
in the detailed description of the present invention, a brief
description of each drawing is presented, in which:
[0020] FIG. 1 demonstrates the viscosity of the gelled emulsion of
the invention over time at 90.degree. C.
[0021] FIG. 2 demonstrates the effect of polymer loading on the
viscosity of the gelled emulsion of the invention.
[0022] FIG. 3 demonstrates the effect of concentration of
emulsifying agent in the gelled emulsion on viscosity.
[0023] FIG. 4 demonstrates the effect of the volumetric ratio of
hydrocarbon to methanol in the gelled emulsion of the invention
versus viscosity.
[0024] FIG. 5 demonstrates the build-up of viscosity in a flow loop
of the gelled emulsion of the invention.
[0025] FIG. 6 illustrates the effect of the encapsulated oxidizer
breaker on the viscosity of the aqueous water-soluble solvent
solution of the gelled emulsion of the invention.
[0026] FIG. 7 illustrates the effect of the encapsulated oxidizer
breaker on the emulsion viscosity of the gelled emulsion at
80.degree. C.
[0027] FIG. 8 illustrates the effect of delayed hydration of the
gellant on viscosity of the gelled emulsion.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] The gelled emulsion of the invention is substantially free
of phosphorous and typically exhibits shear-thinning, non-newtonian
behavior. The gelled emulsion contains a high level of an aqueous
water-soluble solvent solution and dispersed organic fluids. The
gelled emulsion further, optionally, contains gaseous components.
The presence of such gaseous components is especially desirable
when the emulsion is to be used in the fracturing of gas wells.
[0029] In a preferred embodiment, the emulsion contains no greater
than 1 volume percent of phosphorous. In a most preferred
embodiment, the emulsion is phosphorous-free.
[0030] The gelled emulsion exhibits relatively stable rheological
characteristics at relatively high temperatures and may
advantageously be formulated from solid or liquid components.
[0031] The gelled emulsion may be employed in any application known
in the art in which, for example, gelled hydrocarbons are suitable
for use. Examples of possible applications include, but are not
limited to, well treatment fluids (including stimulation fluids
such as fracture fluids, matrix stimulation fluids, acidizing
fluids, hydrocarbon-based treatment fluids etc.), drilling fluids
(such as drilling muds, drill-in fluids, workover fluids, packer
fluids, completion fluids, fluids for use with coil tubing, etc.),
pipeline treatment fluids (such as gelled pipeline pigs, separation
plugs, etc.), as well as process facility treatment fluids (such as
gelled fluids for cleaning and/or chemical processing equipment
used in oil field facilities, refineries, chemical plants,
refineries, etc.).
[0032] The gelled emulsion is formed from the combination of an
aqueous water-soluble solvent solution, a dispersed organic fluid,
polymeric viscosifying agent and emulsifying agent. In addition,
the gelled emulsion may contain an oxidizer or acid as a polymer
degrading agent and/or emulsion breaker.
[0033] The emulsion may be composed of an external phase containing
the aqueous water-soluble solvent solution and polymeric
viscosifying agent and an internal phase of the dispersed organic
fluid. The external phase further may contain the oxidative or
acidic breaker. The internal phase may further contain a foaming or
gasifying agent. The emulsifying agent serves as coalescence
barrier to the external and internal phases, the hydrophobic
portion of the emulsifying agent lying in the internal phase and
the hydrophilic portion lying in the external phase.
[0034] The gelled emulsions offer substantially stable viscosities
at temperatures up to at least about 175.degree. F., alternatively
up to at least about 200.degree. F., alternatively up to at least
about 250.degree. F. Further, the gelled emulsions may exhibit
stable viscosity at temperatures as low as -30.degree. F.,
typically encountered, for example, in pipelines. In such cases,
rheology may be modified to suit colder conditions, such as by
using lower percentages of polymeric viscosifying agent than that
specifically recited herein.
[0035] The water-soluble solvent is a C.sub.1-C.sub.4 alkanol,
preferably methanol, ethanol or isopropanol, more preferably
methanol. Other water-soluble solvents may also be used, such as
ethylene glycol, propylene glycol, acetone, methylene sulfonic
acid, acetic acid, formic acid and hydroxy acetic acid as well as
mixtures thereof. When used, ethylene glycol may be recovered after
the fracture treatment and reused. Use of acetone may lend to
improved solvency to organic deposits. Use of acetic acid is
desirable when the reservoir rock contains siderite beds [Fe (II)
carbonate] or other acid soluble components.
[0036] Further, the water of the aqueous water-soluble solvent
solution can be any aqueous solution such as distilled water, fresh
water, salt water (brine), etc.
[0037] The amount of water-soluble solvent in the gelled emulsion
is that amount sufficient to render acceptable permeability regain
to the emulsion. Increased concentration of solvent in the aqueous
water-soluble solvent solution translates to greater solubility of
the oleophilic portion of the emulsifying agent.
[0038] Typically, the aqueous water-soluble solvent solution
contains between from about 15 to about 80 volume percent of
solvent and the remainder water. The aqueous water-soluble solvent
solution typically constitutes between from about 15 to about 65
volume percent of the gelled emulsion. When methanol is used as the
water-soluble solvent, above 60 volume percent of methanol is not
desired. At higher percentages, fire hazards increase and the
solubility of hydrocarbons and condensates increase. Since the
emulsion contains a high percentage of water-soluble solvent (in
combination with the dispersed organic fluid), the emulsion is
particularly efficacious when used in gas wells.
[0039] The polymeric viscosifying agent may be a conventional
thickening or gelling agent known in the art, such as those
containing one or more hydroxyl, carboxyl, sulfate, sulfonate,
amino or amide functional groups. Other suitable gelling agents are
polysaccharides and polysaccharide derivatives containing
monosaccharides such as glucose, galactose, mannose, xylose,
arabinose and fructose. Suitable polysaccharide derivatives
include, but are not limited to, guar gum derivatives such as HPG
(hydroxypropyl guar), HEG (hydroxyethyl guar) and CMHPG
(carboxymethyl hydroxypropyl guar), cellulose and its derivatives
such as CMHEC (carboxymethyl hydroxyethyl cellulose) and HPC
(hydroxyl propyl cellulose), xanthan gum and starch derivatives.
Synthetic polymers can be used as gelling agents. A few of these
include, but are not limited to, polyacrylate, polymethylacrylate,
polyacrylamide, acrylamide methyl propane sulfonic acid copolymers,
polyvinyl alcohol, polyvinyl pyrrolidone, and maleic anhydride
methyl vinyl ether copolymers and polyethylene oxide. Typically,
the amount of polymeric viscosifying agent in the gelled emulsion
is between from about 3 to about 10 kg/m.sup.3. (Measurements in
terms of kg/m.sup.3, or L/m.sup.3, herein refer to the aqueous
water-soluble solvent solution, not the weight of the total
emulsion. Other concentrations of components of the emulsion
described herein are based on the weight of the aqueous
water-soluble solvent solution.)
[0040] The viscosity of the gelled emulsion typically varies with
the nature of the dispersed organic fluid. Suitable as the
dispersed organic fluid are those suitable for forming an organic
fluid gel, including those organic fluids commonly employed in
oilfields, pipelines and refineries as well as chemical plants.
Suitable dispersed organic fluids include, but are not limited to,
hydrocarbon-based fluids. Typically, between from about 50 to about
85 volume percent of the gelled emulsion contains the dispersed
organic fluid.
[0041] Types of suitable dispersed organic fluids include, but are
not limited to, aliphatic, alicyclic and aromatic hydrocarbons,
esters, such as oily esters and alkoxylated esters as well as
mixtures thereof.
[0042] Specific examples of suitable aliphatic hydrocarbons
include, but are not limited to, alkanes such as propane, n-butane,
isobutane, n-hexane, n-octane, n-decane, n-tridecane, etc. Other
aliphatics include alkenes and alkadienes. Alicyclic compounds
include cyclohexane, etc. Specific examples of suitable aromatics
include, but are not limited to, benzene, toluene, xylene,
ethylbenzene and other alkyl benzenes, naphthalene, etc. In a
preferred embodiment, the dispersed organic fluid is lighter than
diesel such as C.sub.8-C.sub.15 alkanes.
[0043] Particular examples of commercial aromatic products include,
but are not limited to, "FRACSOL", "FRACSOL-S", and "XYSOL" from
EnerChem Canada or Amsol of the United States, or "RX-2100" from
Canadian National Resources Limited of Calgary, Canada. Other
specific examples of suitable dispersed organic fluids include, but
are not limited to at least one of diesel, gasoline, kerosene,
reformate, naphthalene, xylene, toluene, mineral oil, light mineral
oil, condensate, crude oil, lubricating oils, or mixtures thereof
(such as diesel mixed with condensate to lower API gravity, etc.).
Other dispersed organic fluids such as alkanes (such as hexane) and
derivatized alkanes (such as alkylhexanes), may also be
employed.
[0044] Other suitable organic fluids (including oily esters, such
as those derived from long chain acids and/or alcohols), are
described in U.S. Pat. No. 5,519,063, which is incorporated by
reference herein in its entirety. Also suitable are synthetic oils
(including, but not limited to, synthetic hydrocarbon-base oils,
ester-type oils, alkylene polymers, polysiloxanes, etc.). Also
suitable are more environmentally compatible (e.g., biodegradable)
natural or synthetic dispersed organic fluids such as Exxon's
"ESCAID 90" or "ESCAID 110", or refined kerosene (such as "LOTOX"
available from Exxon), "HYDROSOLV P150" or "HYDROSOLV B100" (from
Shrieve Chemical Products), "ISOPAR L" or "ISOPAR M" (from
Nalco-Exxon Chemical Company), etc. Natural dispersed organic
fluids such as animal oils and vegetable oils may also be suitable
including, but not limited to, linseed oil, palm oil, cotton seed
oil, rapeseed oil, soybean oil, olive oil, canola oil, sunflower
oil, peanut oil, etc.
[0045] Two or more of the representative examples above may be
mixed together to form a dispersed organic fluid having desired
characteristics. In one exemplary embodiment, an organic fluid may
be a liquid hydrocarbon that is at least one of diesel, condensate,
or mixtures thereof. Further information on suitable organic-based
fluids may be found in U.S. Pat. No. 6,302,209, which is
incorporated herein by reference in its entirety.
[0046] The volumetric ratio of the viscosified water-soluble
solvent solution to dispersed organic fluid in the gelled emulsion
is typically between from about 1:5 to 1:2, preferably about 1:3.
The gelled emulsion has particular applicability in fracturing
using conventional proppants, such as sand, as well as lightweight
(and ultra lightweight) proppants.
[0047] The gelled emulsion further preferably contains a dispersed
gas component. Suitable dispersed gases are carbon dioxide and
nitrogen. Typically, when present, the amount of dispersed gas in
the emulsion is between from about 10 to about 70 volume percent,
preferably about 25 volume percent.
[0048] The emulsifying agent is present in the gelled emulsion in
an amount between from about 0.5 to about 3.5, preferably from
about 1.0 to about 2.5, volume percent based on the aqueous
water-soluble solvent solution. A suitable emulsifying agent for
use in the invention may be ascertained by preparing a fully
hydrated gel of the water-soluble solvent/water solution using 3
kg/m.sup.3 gellant and any buffer or agent deemed necessary to
hydrate the gel. About 100 ml of the hydrated gel may then be
placed in a blender equipped with a variable transformer. To the
methanol/water blend may then be added 20 L/m.sup.3 of the test
emulsifying agent. 300 ml of the hydrocarbon phase may then be
slowly added while stirring with the variable transformer set to
.about.40 volts. Stirring may then be continued for about 2
minutes. If an emulsion is formed, the emulsion may then be placed
in a jar in a 70.degree. C. water bath for about 30 minutes and the
viscosity may then be measured at a shear rate of 100/s. If the
viscosity of the emulsion is greater than 200 centipoise, the
emulsifying agent is then suitable for use in the invention.
[0049] The emulsifying agent is preferably at least one member
selected from (1) alkoxylated non-ionic emulsifiers having a
lipophilic portion comprising a C.sub.12-C.sub.36 alkyl, dialkyl or
alkylaryl and a hydrophilic portion having 20 to 150 moles of
polyalkylene oxide; (2) an anionic, cationic or
zwitterionic/amphoteric emulsifier having a lipophilic portion
comprising a lipophilic portion comprising a C.sub.12-C.sub.22
alkyl, dialkyl or alkylaryl group and a hydrophilic portion having
10 to 80 moles of polyalkylene oxide; (3) an ethylene
oxide/propylene oxide block copolymer comprising between from about
10 to about 50 moles of propylene oxide and from about 20 to about
150 moles of ethylene oxide; and (4) polyoxyalkylene sorbitan fatty
acid esters. A class of surfactants known as "splittable
surfactants" as taught in U.S. Pat. No. 5,774,064 are of particular
interest because they can be deactivated by simply lowering the pH.
This may be accomplished by an encapsulated acid, a slowly soluble
acid or a low pH buffer.
[0050] The emulsifying agent is preferably at least one member
selected from non-ionic emulsifiers; anionic, cationic or
zwitterionic/amphoteric emulsifiers; ethylene oxide/propylene oxide
block copolymers; and polyoxyalkylene sorbitan fatty acid esters.
The emulsifying agent is preferably selected in order to maintain
the emulsion stable at reservoir temperatures for at least 10
minutes under static conditions.
[0051] The emulsifying agent is typically chosen such that the
following three criteria are met. First, the hydrophobic
(lypophilic) portion of the molecule is sufficiently large to be
effective in the aqueous water-soluble solvent solution. Second,
the hydrophile/lypophile balance is sufficiently high to form and
stabilize an emulsion having a low volume of aqueous water-soluble
solvent solution as the external phase and larger volume of
water-immiscible organic fluid as the dispersed or internal phase.
Third, the molecule is capable of exhibiting efficient packing in
the stabilizing film. An over-abundance of branches, unsaturated
bonds and/or aromatic groups in the lyophilic portion of the
molecule may lead to a film that is too loose to serve as a barrier
to coalescence.
[0052] Published HLB values, such as those in "McCutcheon's Volume
1: Emulsifiers and Detergents 1998 North American Edition"--MC
Publishing Co., may be used to select a suitable emulsifying agent.
To be suitable, the HLB value for the emulsifying agent should be
between from about 10 to about 20 and preferably from about 16 to
about 18.
[0053] For ionic surfactants, it is may be desired to use a
measured relative solubility number (RSN) in place of the HLB. The
emulsifying agent typically exhibits an (RSN) in excess of 10,
preferably between from about 13 to about 17. RSN is a measure of
the amount of water required to reach the cloud point at 25.degree.
C. of the solution of 1 gram of the "solvent free" emulsifying
agent dissolved in 30 ml of a solvent system comprising 4 volume
percent xylene in dioxane and is further based on the
hydrophile-lipophile character (see H. N. Greenwold et al,
Analytical Chemistry, Vol. 28 Nov. 11, November, 1956 on pages
1693-1697) and further referenced in U.S. Pat. No. 4,551,239,
herein incorporated by reference.
[0054] The emulsifying agent allows the dispersed organic fluid to
become the dispersed phase of the emulsion and the aqueous
water-soluble solvent solution to become the external phase. The
emulsifying agent further provides stability to the emulsion by
providing the means to keep the gelled emulsion in an emulsified
state under desired operating conditions. Stability to the emulsion
may further be affected by selection of polymeric viscosifying
agent and the loading of the polymeric viscosifying agent. In order
to allow the emulsifying agent to resist the mutual solvent effect
of the high solvent content of the aqueous water-soluble solvent
solution, the molecular weight of the emulsifying agent is high,
thereby prohibiting the hydrophobic end of the emulsifying agent
from entering the water phase of the emulsion. As a result of its
high molecular weight, the hydrophobic portion of the emulsifying
agent stays at the hydrocarbon/water interface where it stabilizes
the emulsion at high temperature downhole conditions.
[0055] In a preferred mode, the emulsifying agent is a
freeze-proofed solution.
[0056] The emulsifying agent may also be employed to assist in the
hydration of the polymeric viscosifying agent. In so doing, the
emulsifying agent assists in dispersement of the polymeric
viscosifying agent in such a way that the viscosifying agent may
hydrate, gel and/or increase the viscosity of the fluid. This
minimizes the initial viscosity of the gelled emulsion and allows
the emulsion viscosity to build with time thereby minimizing
pumping friction pressure.
[0057] Suitable alkoxylated non-ionic emulsifiers are those having
a lipophilic portion comprising a C.sub.12-C.sub.36, preferably
from about C.sub.15-C.sub.22, alkyl, dialkyl and alkylaryl and a
hydrophilic portion having between from about 20 to about 150 moles
of polyalkylene oxide, preferably polyethylene oxide or a
polyethylenepropylene block oxide, most preferably polyethylene
oxide.
[0058] Suitable anionic, cationic or zwitterionic/amphoteric
emulsifiers are those having a C.sub.15-C.sub.22 alkyl, dialkyl or
alkylaryl group as lipophilic portion and a hydrophilic portion
having between from about 10 to about 80 moles of polyalkylene
oxide in addition to the charged groups; preferably polyethylene
oxide or a polyethylenepropylene block oxide, most preferably
polyethylene oxide. Preferred anionic emulsifiers include
alkoxylated carboxylates, alkoxylated ether sulfates as well as
alkoxylated alpha olefin sulfonates. Suitable cationic emulsifiers
include alkoxylated amines.
[0059] Suitable as the ethylene oxide/propylene oxide block
copolymer are those having between from about 10 to about 50 moles
of propylene oxide and from about 20 to about 150 moles of ethylene
oxide.
[0060] Preferred zwitterionic emulsifiers are betaines, such as
fatty acid amido alkyl betaines like cocoamidopropyl betaines as
well as sulfobetaines.
[0061] Suitable polyoxyalkylene sorbitan fatty acid esters include
those wherein the polyoxyalkylene oxide is polyethylene oxide or a
polyethylenepropylene block oxide, most preferably polyethylene
oxide.
[0062] Particularly preferred surfactants are those set forth in
Table I below:
TABLE-US-00001 TABLE I Manufacturer Trade Name RSN HLB C Min C Max
Moles EO Class Structure Ethox Ethox MS-100 16.0 18.6 18 18 100
Nonionic Ethoxylated Fatty Acid POE(100) Stearyl-C18 Ethox Ethox
MS-40 15.8 17.2 18 18 40 Nonionic Ethoxylated Fatty Acid POE(40)
Stearyl-C18 Ethox Ethox MI-14 10.6 13.0 18 18 14 Nonionic
Ethoxylated Fatty Acid POE(14) Isostearyl C-18 Ethox Ethox 3482
16.4 18.8 Nonionic Ethoxylated fatty Acid (unspecified) Ethox Ethal
CSA 40/70% 16.8 17.4 16 18 40 Nonionic Ethoxylated Alcohols POE(40)
Cetyl-Stearyl C16-C18 Alcohol Ethox Ethal LA-50 16.8 18.3 12 12 50
Nonionic Ethoxylated Alcohols POE(50) Lauryl C12 Alcohol Ethox
Ethox TAM-25 17.0 16.0 16 18 25 Cationic Ethoxylated Tallow Amine
POE(25) C-16-18 Ethox Ethox SAM-50 15.8 17.8 16 16 50 Cationic
Ethoxylated Stearyl Amine POE(50) C-18
[0063] The emulsifying agent used in the invention exhibits water
wetting characteristics and can be chosen so as to be compatible
with potassium chloride or synthetic temporary and permanent clay
stabilizers.
[0064] One or more other phosphorous-free additives may further be
employed to alter the characteristics of the gelled emulsion fluid.
Such additives may include any additive known in the art that is
suitable for altering characteristics of aqueous gels, or for
assisting with or modifying the combination or reaction of
individual ingredients to form such gels. Examples of such
additives which may be employed include, but are not limited to,
buffering agents, cross-linking agents, scale/corrosion inhibitors
and agents for controlling fines or clay swelling or migration such
as potassium chloride or KCl substitutes of the type based on
quaternary amine chlorides, such as CC-2, a product of BJ Services
Company or polycationic clay control additives such as Claymaster
5C.TM., a product of BJ Services Company, or mixtures of these clay
control additives.
[0065] While stability of the emulsion at room temperature is not
dependent on pH, it is desirable to buffer the pH to be between
from about 4 to about 6 to prevent premature acid hydrolysis of the
polymeric viscosifying agent at downhole conditions and to assist
hydration of the polymeric viscosifying agent at surface
conditions.
[0066] The gelled emulsions may be prepared in any manner suitable
for combining the components to form the gel. For example, the
gelled emulsions may be prepared by blending the aqueous
water-soluble solvent solution and polymeric viscosifying agent to
form a gel and then introducing the emulsifying agent and the
dispersed organic fluid. The remaining components, e.g., optional
oxidizer and/or breaker and gasifying agent, may then be added. The
breaker and/or oxidizer may even be added after the gelled emulsion
has been formed, such as at a point at or near blender discharge
manifold.
[0067] The oxidative or acidic breaker may then be added to the
formulation to cause the gelled fluid to lose its structure,
viscosity, etc. Typically, the gelled emulsion contains between
from about 0.2 to about 30, more typically between from about 2 to
about 25, kg/m.sup.3 of oxidative or acidic breaker.
[0068] In one embodiment, one or more breaker materials may be
added for providing a delayed reduction in viscosity of gelled
emulsions prepared herein. Such viscosity reduction may be
desirable, for example, when a gelled fluid is used as a well
treatment fluid such as a hydraulic fracturing fluid. In such a
case, a breaker material may be combined with other components of
the gelled emulsion prior to introduction of the fluid downhole,
and may be formulated so that a gelled fluid viscosity is
substantially maintained or increased during the time the gelled
emulsion is displaced downhole and into the formation but is
decreased, for example, after sufficient time has occurred to allow
transport of proppant into the subterranean formation.
[0069] Any material(s) suitable for imparting viscosity reduction
characteristics to the disclosed gelled emulsions may be employed
as a breaker. Examples of suitable materials include, but are not
limited to, oxidizing agent, amines, acids, acid salts,
acid-producing materials, etc. The breaker is preferably an acid
breaker such as hydrochloric acid, formic acid or sulfamic acid or
alternatively an acid salt such as sodium bisulfate.
[0070] The oxidizing agent is preferably an alkaline earth
peroxide, an encapsulated persulfate, a catalyzed organic peroxide
or a hydrochlorite bleach.
[0071] The gelled emulsions may be employed as a component of a
well treatment fluid, such as a drilling, stimulation, completion
or workover fluid. In this regard, the disclosed gelled emulsions
may be introduced into a wellbore and/or subterranean formation to
function as viscosifiers or gelled components of circulating, lost
circulation, or kill fluids (drilling muds, drill-in fluids, packer
fluids, workover fluids, gelled pills, etc.), as well as fulfilling
similar purposes as components of stimulation fluids (such as
fracture fluids, gelled acids, foamed fluids, diversion fluids,
etc.), injection profile modification fluids, etc. With benefit of
this disclosure, it will be understood that the disclosed gelled
emulsions may be employed in any drilling or well treatment
application known in the art.
[0072] The components of the gelled emulsions may be combined in a
batch process performed at the wellsite using mixing vessels such
as frac tanks. Alternatively, the components may be batched mixed
away from the wellsite and transported to the wellsite using
methods known in the art.
[0073] In a preferred embodiment, the gelled emulsion is prepared
on the fly using continuous mixing methods at the wellsite, such as
those employing concomitantly introduced component process streams.
In this regard, any continuous mixing method known in the art which
is suitable for combining the disclosed components to form gelled
gelled emulsion fluids may be employed. For example, when
formulating well stimulation fluids, the dispersed organic fluid
and alcohol/water blend may be introduced into a suction manifold
simultaneously with a slurry of polymeric viscosifying agent along
with the emulsifying agent. Once the gelled emulsion has formed in
the tank or blender tub, proppant (when desired) as well as foaming
agent or gasifying agent is introduced through a high pressure pump
just prior to the gelled emulsion being introduced into the
wellbore.
[0074] When introduced downhole, initial viscosity of the gelled
emulsions set forth herein may be regulated by varying the
concentration of the emulsifier, the ratio of hydrocarbon to liquid
and the amount of gelling agent. By doing so, friction pressure
during the pumping of the fluid downhole may be decreased and thus
balanced As a result, the gelled emulsions exhibit low leak-off,
excellent proppant transport abilities, clean highly conductive
fractures, excellent fracture face permeability regain and are
relatively inexpensive.
[0075] The gelled emulsions may further be employed within pipeline
interiors as a pipeline treatment fluid to clean and/or convert
pipeline transmission lines, isolate a pipeline from invasive
materials, displace solid materials and/or fluids through a
pipeline, or to separate pipeline products from each other or from
other materials within the pipeline. Specific examples of such uses
include, but are not limited to, use of a gelled plug or pig to
isolate two separate fluids (such as different pipeline products)
under static or dynamic conditions of flow within a pipeline
interior. The disclosed gelled emulsions may also be used to remove
debris or contaminants from the interior of the pipeline, such as
by displacing a gelled pig of a treatment fluid containing
non-phosphate organic liquid gel through at least a portion of a
pipeline.
[0076] In one exemplary embodiment, when used as a gel pig, the
gelled emulsion may be employed in conjunction with a mechanical
pig as is known in the art. In one exemplary embodiment, a gel pig
may be formed from a liquid organic gel and displaced through a
pipeline by fluid under pressure. In this regard, displacement
fluid may be gas or liquid, depending upon the needs of the user
and the availability of fluids. A gel pig may be used alone or as
an element of a "pig train" in a pipeline cleaning process. Such a
pig train may be formed, for example, by preceding and/or following
a pipeline treatment fluid gel plug with mechanical pigs and/or
other chemical pig segments. Such chemical pig segments may be of
the same or different composition and may include the additives
such as corrosion inhibitors, bactericides, passivation agents,
etc. Such chemical pig segments may be liquids or gels.
[0077] In other exemplary embodiments, the gelled emulsion may be
employed as a separation plug or pig to separate one or more
materials, such as pipeline product fluids (e.g., hydrocarbons,
paraffins, asphaltenes, fuel oil, condensate, etc.), existing
within a pipeline, under static or dynamic conditions, or as a
microplug to remove fluids, solids and semi-solids (such as sand,
tar, corrosion products and other debris and contaminants, etc.)
from the interior of a pipeline.
[0078] In other embodiments of the disclosed method and
compositions, the gelled fluids may be employed in fluid processing
applications including, but not limited to, oil field production
facility, refinery, and chemical plant applications.
[0079] The following examples will illustrate the practice of the
present invention in its preferred embodiments. Other embodiments
within the scope of the claims herein will be apparent to one
skilled in the art from consideration of the specification and
practice of the invention as disclosed herein. It is intended that
the specification, together with the example, be considered
exemplary only, with the scope and spirit of the invention being
indicated by the claims which follow. All otherwise stated, all
percentages are weight percentages.
EXAMPLES
[0080] GM-55 and GM-60 refer to modified hydroxypropyl guars
wherein the molar substitution (defined as the number of moles of
hydroxyalkyl groups per mole of anhydroglucose) is between from
about 0.80 to about 1.20, a product of BJ Services Company;
[0081] Ethal CSA 40/70% is an ethoxylated alcohol POE (50) lauryl
C12 alcohol, commercially available from Ethox;
[0082] Fracsol.RTM. is a 100% oil based fracturing fluid,
commercially available from Enerchem International Inc.
Example 1
[0083] An emulsion, not containing a breaker, was prepared by
making a base gel containing 60 vol % methanol in water to which
was added 2 L/m.sup.3 acetic acid (60%), 2 L/m.sup.3 of a 60%
choline chloride solution (a temporary clay stabilizer which avoids
the swelling of the clay), 8 kg GM-55 methanol gellant and 20
l/m.sup.3 CSA-40/70. The acetic acid was used as a buffer to ensure
hydration of the GM-55 gellant. One volume of this solvent blend
was then emulsified with 3 volumes of Fracsol. The viscosity was
then measured on a Brookfield Model PVS high pressure rheometer
equipped with a B5 bob. The results are graphically displayed in
FIG. 1.
Example 2
[0084] An emulsion was prepared as set forth in Example 1 except
that the concentration of gellant was varied. The results are
graphically displayed in FIG. 2.
Example 3
[0085] An emulsion was prepared as set forth in Example 1 except
that the concentration of gellant was 3 kg/m.sup.3 and the
concentration of emulsifying agent was varied. FIG. 3 illustrates
the effect of emulsifier concentration on viscosity of the gelled
emulsion.
Example 4
[0086] An emulsion was prepared as set forth in Example 1 except
that the base gel contained only 3 kg/m.sup.3 gellant (GM-55) and
varying ratios of Fracsol. The shear rate profile for the
Brookfield rheometer was obtained every 5 minutes at 150/s, 125/s,
100/s and 75/s followed by two minute zeroing and then 100/s until
the next ramp. The effect of the varied ratio of hydrocarbon to 60%
methanol is set forth in FIG. 4.
Example 5
[0087] The gelled methanol solution obtained in Example 1 ("New
FracFluid") was added to the reservoir of a flow loop. A comparison
gelled emulsion was obtained in a similar manner described in
Example 1 but using a 3:1 volume ratio of Fracsol to gelled water
containing 7 kg/m.sup.3 guar gellant, 12 L/m.sup.3 emulsifier
(commercially available as PS-3 from BJ Services Company), 1
L/m.sup.3 of a 60% choline chloride solution and 1 L/m.sup.3 of
Claymaster 5C.TM., a product of BJ Services Company. The flow loop
was a 20 ft stainless steel tubing with an inner diameter of 0.417
in. The circulation rate was 200 ml/s. FIG. 5 shows the pressure
build-up on the flow loop. (Air entrainment likely caused the
pressure to drop off on the NewFrac Fluid.)
Example 6
[0088] A gelled emulsion was obtained in accordance with the
procedures of Example 1 but using 10 kg/m3 encapsulated oxidative
breaker (commercially available as HyPerm KP, a product of BJ
Services Company), 8 kg/m.sup.3 gellant (GM-55), 20 L/m.sup.3 Ethal
CSA 40/70, 2 L/m.sup.3 acetic acid (60%), 2 L/m.sup.3 buffer
(commercially available as BF-7LD from BJ Services Company), 1
L/m.sup.3 of a 60% choline chloride solution and 1/m.sup.3
Claymaster 5C. The effect of the encapsulated oxidizer breaker on
the viscosity of the gelled 60% methanol water blend at 80.degree.
C. is set forth in FIG. 6.
Example 7
[0089] A gelled emulsion was obtained in accordance with the
procedure set forth in Example 1 but using 8 kg/m.sup.3 gellant
(GM-55), 20 l/m.sup.3 emulsifier (Ethal CSA-40/70), 1 l/m.sup.3 of
a 60% choline chloride solution, 1 l/m.sup.3 Claymaster 5C, 2
l/M.sup.3 acetic acid (60%), 2 kg/M.sup.3 potassium carbonate, 3:1
Fracsol:60% methanol. Various concentration of encapsulated
persulfate breaker (HyPerm KP) was then added. FIG. 7 illustrates
the effect of the encapsulated oxidizer breaker on the emulsion
viscosity at 80.degree. C.
Example 8
[0090] A base fluid was prepared by mixing 6 kg/m.sup.3 gellant
(GM-60), 60% methanol, 35 L/m.sup.3 CSA 40/42%, 0.5 kg/m.sup.3
Borax, 0.67 kg/m.sup.3 potassium carbonate, 1 L/m.sup.3 of a 60%
choline chloride solution and 1 L/m.sup.3 Claymaster 5C. The base
fluid was then emulsified with 3 parts by volume of Frascol and
mixed at high shear 3:1 v/v Fracsol. The viscosity of the emulsion
was read on a Grace M3500 Rheometer. 2 L/m.sup.3 acetic acid (60%)
was then stirred into the emulsion at low shear and the development
of the emulsion measured on the rheometer. FIG. 8 displays the
effect on the reduction of the initial viscosity by delayed
hydration of the gellant.
Examples 9-14
[0091] A base gel was prepared by blending a blend of 60%
methanol/40% water, 3 kg/m.sup.3, a methanol soluble guar
(hydroxypropyl guar), available from BJ Services Company Canada and
B.J. Services Company, U.S.A., under the trade mark GM-55 or GM-60;
2 L/m.sup.3 acetic acid (60%), 2 L/m.sup.3 of Claymaster 5C.TM., 1
L/m.sup.3 of a 60% choline chloride solution, 2 kg/m.sup.3 of
potassium carbonate buffer and 20 L/m.sup.3 various emulsifiers. To
this base fluid was added the dispersed organic fluid, Fracsol, a
product of EnerChem wherein the volumetric ratio of
Fracsol:methanol/water blend was 3:1. The mixture was then
subjected to high shear on a Waring blender at speed of 4000 rpm
(40 volts on the rheostat) for about 1 minute. The sample was then
heated for about 1 hour at 70.degree. C. While the stability of the
emulsion is not sensitive to pH, the presence of the acetic acid
serves to enable hydration of the HPG when the emulsion is
introduced downhole. The emulsifiers used are set forth in Table
II:
TABLE-US-00002 TABLE II Number of Carbon Moles Emulsifier Name Type
Polar groups RSN HLB range EO A Alcohol ether Anionic 1 17.0 0
sulfate B Ethoxylated Non-ionic 0 16.0 18.6 18 100 fatty acid POE
(100) Stearyl C Ethoxylated Non-ionic 0 15.8 17.2 18 40 fatty acid
POE (40) Stearyl D Ethoxylated Non-ionic 0 10.6 13.0 18 14 fatty
acid POE (14) isostearyl E Ethoxylated Non-ionic 0 16.4 18.8 fatty
acid unspecified F Ethoxylated Non-ionic 0 16.8 17.4 16/18 40
alcohol POE (40) cetyl/stearyl (40/70 volume)
[0092] The viscosity of the blend using Fracsol, a product of
EnerChem, as the dispersed organic fluid, was then measured with a
Fann 35 rheometer equipped with an R1B2 geometry at 300 and 100
rpm. The viscosity of the emulsions at a shear rate of 100/s was
then calculated and the results are set forth in Table III
below:
TABLE-US-00003 TABLE III Viscosity, 100 Viscosity, Ex. 300 rpm, 100
rpm, Cps@100/s, 300 rpm, rpm, Cps@100/s, No. Emulsifier RT RT RT
70.degree. C. 70.degree. C. 70.degree. C. Comp. A No No 1 No No 1
Ex. 9 emulsion emulsion emulsion emulsion 10 B 177 109 1693 82 41
767 11 C 190 122 1827 64 40 614 12 D 125 82 1205 26 14 245 13 E 191
120 1831 94 60 903 14 F 120 74 1149 74 54 722
Examples 15-19
[0093] The protocol of Examples 9-14 above was repeated except that
the dispersed organic fluid was RX-2100, a product of Canadian
National Resources Limited. The results are set forth in Table IV
below:
TABLE-US-00004 TABLE IV Ex. 300 rpm, 100 rpm, Viscosity, 300 rpm
100 rpm, Viscosity, No. Emulsifier RT RT Cps@100/s, RT 70.degree.
C. 70.degree. C. Cps@100/s, 70.degree. C. 15 B 147 97 1418 79 46
751 16 C 146 92 1401 73 47 702 17 D 81 52 779 6 4 58 18 E 160 98
1530 84 63 821 19 F 148 1425 1323 44 30 426
[0094] From the foregoing, it will be observed that numerous
variations and modifications may be effected without departing from
the true spirit and scope of the novel concepts of the
invention.
* * * * *