U.S. patent application number 10/691321 was filed with the patent office on 2005-04-28 for liquid gelling agent concentrates and methods of treating wells therewith.
Invention is credited to Blauch, Matthew, McCabe, Michael A., Slabaugh, Billy.
Application Number | 20050087341 10/691321 |
Document ID | / |
Family ID | 34521850 |
Filed Date | 2005-04-28 |
United States Patent
Application |
20050087341 |
Kind Code |
A1 |
McCabe, Michael A. ; et
al. |
April 28, 2005 |
Liquid gelling agent concentrates and methods of treating wells
therewith
Abstract
The present invention provides liquid gelling agent concentrates
and methods of treating wells therewith. A liquid gelling agent
concentrate of this invention comprises an environmentally safe
hydrocarbon carrier liquid, an organophillic clay suspending agent,
a surfactant for dispersing the organophillic clay suspending agent
in the carrier liquid and a particulate aqueous fluid gelling agent
suspended in the carrier liquid.
Inventors: |
McCabe, Michael A.; (Duncan,
OK) ; Slabaugh, Billy; (Duncan, OK) ; Blauch,
Matthew; (Duncan, OK) |
Correspondence
Address: |
Robert A. Kent
Halliburton Energy Services
2600 S. 2nd Street
Duncan
OK
73536-0440
US
|
Family ID: |
34521850 |
Appl. No.: |
10/691321 |
Filed: |
October 22, 2003 |
Current U.S.
Class: |
166/278 ;
166/305.1; 166/308.2; 166/308.4; 507/905; 507/922; 507/925 |
Current CPC
Class: |
C09K 8/64 20130101 |
Class at
Publication: |
166/278 ;
166/305.1; 166/308.2; 166/308.4; 507/905; 507/922; 507/925 |
International
Class: |
E21B 043/04; E21B
043/26 |
Claims
What is claimed is:
1. A liquid gelling agent concentrate comprising: an
environmentally safe hydrocarbon carrier liquid; an organophillic
clay suspending agent; a surfactant for dispersing said
organophillic clay suspending agent in said carrier liquid; and a
particulate aqueous fluid gelling agent suspended in said carrier
liquid.
2. The gelling agent concentrate of claim 1 wherein said
environmentally safe hydrocarbon carrier liquid is selected from
the group consisting of a mixture of hydrocarbons having in the
range of from about 6 to about 13 carbon atoms obtained by treating
a petroleum fraction with hydrogen in the presence of a catalyst, a
mixture of hydrocarbons having in the range of from about 10 to
about 25 carbon atoms obtained by catalytic hydrogenation of vacuum
gas oils followed with dewaxing by hydroisomerization and
stabilization by hydrotreating at high pressures, a mixture of
severely hydrocracked low toxicity mineral oils and synthetic
isoalkanes, polyalpha olefins, mixtures of C.sub.10-C.sub.1-4
alkanes and C.sub.8 and higher alkenes, mixtures of linear alpha
and internal olefins, hydrocarbon blends containing 93% linear
paraffins, blends of isoalkanes and isoalkenes and alcohols, blends
of linear internal olefins having from about 16 to about 18 carbon
atoms, blends of linear alpha-olefins having 10 or more carbon
atoms, vegetable oils, and vegetable esters.
3. The gelling agent concentrate of claim 1 wherein said
environmentally safe hydrocarbon carrier liquid is a mixture of
hydrocarbons having in the range of from about 6 to about 13 carbon
atoms obtained by treating a petroleum fraction with hydrogen in
the presence of a catalyst.
4. The gelling agent concentrate of claim 1 wherein said
environmentally safe hydrocarbon carrier liquid has a flash point
above about 175.degree. F. and a pour point below about -49.degree.
F.
5. The gelling agent concentrate of claim 1 wherein said
environmentally safe hydrocarbon carrier liquid is present in said
concentrate in an amount in the range of from about 25% to about
55% by weight thereof.
6. The gelling agent concentrate of claim 1 wherein said
organophillic clay suspending agent is selected from the group
consisting of quaternary ammonium bentonite clay, quaternary
ammonium montmorillinite clay and quaternary ammonium hectorite
clay.
7. The gelling agent concentrate of claim 6 wherein two of the
quaternary ammonium substituents of the organophillic clay
suspending agent are alkyl radicals having in the range of from 1
to 10 carbon atoms and two of the substituents are alkyl radicals
having in the range of from 10 to 30 carbon atoms.
8. The gelling agent concentrate of claim 1 wherein said
organophillic clay suspending agent is quaternary ammonium
bentonite clay.
9. The gelling agent concentrate of claim 1 wherein said
organophillic clay suspending agent is present in said concentrate
in an amount in the range of from about 0.2% to about 4% by weight
thereof.
10. The gelling agent concentrate of claim 1 wherein said
surfactant for dispersing said organophillic clay suspending agent
in said carrier liquid is selected from the group consisting of
amphoteric surfactants, anionic surfactants, cationic surfactants
and nonionic surfactants.
11. The gelling agent concentrate of claim 1 wherein said
surfactant for dispersing said organophillic clay suspending agent
in said carrier liquid is selected from the group consisting of
nonionic esters, polyethylene glycol esters, ethoxylated acids,
ethoxylated oils, sorbitol esters, ethoxylated sorbitol esters,
ethoxylated alcohols, alcohol alkoxylates, alkanolamides,
quaternary ammonium compounds, dialkyl quaternary ammonium
compounds, benzyl quaternary ammonium compounds, amine oxides,
ethoxylated amines, fatty imidazolines, ether carboxylates,
sulfonates, sulfosuccinates, fatty acid taurates, ether
carboxylates, alkyl betaines, and alkyl amidopropyl betaines.
12. The gelling agent concentrate of claim 1 wherein said
surfactant for dispersing said organophillic clay suspending agent
in said carrier liquid is an ethoxylated alcohol.
13. The gelling agent concentrate of claim 1 wherein said
surfactant for dispersing said organophillic clay suspending agent
in said carrier liquid is present in said concentrate in an amount
in the range of from about 0.1% to about 2% by weight thereof.
14. The gelling agent concentrate of claim 1 wherein said
particulate aqueous fluid gelling agent is selected from the group
consisting of guar, hydroxypropylguar,
carboxymethylhydroxypropylguar, hydroxyethylcellulose,
carboxymethylhydroxyethylcellulose, carboxymethylcellulose, xanthan
and succinoglycan.
15. The gelling agent concentrate of claim 1 wherein said
particulate aqueous fluid gelling agent is guar.
16. The gelling agent concentrate of claim 1 wherein said
particulate aqueous fluid gelling agent is present in said
concentrate in an amount in the range of from about 25% to about
55% by weight thereof.
17. A method of treating a subterranean zone penetrated by a well
bore using a viscous aqueous treating fluid comprising the steps
of: (a) mixing a liquid gelling agent concentrate with an aqueous
fluid to thereby form a viscous aqueous treating fluid, said liquid
gelling agent concentrate comprising an environmentally safe
hydrocarbon carrier liquid, an organophillic clay suspending agent,
a surfactant for dispersing said organophillic clay suspending
agent in said carrier liquid and a particulate aqueous fluid
gelling agent suspended in said carrier liquid; and (b) introducing
said viscous aqueous treating fluid into said subterranean
zone.
18. The method of claim 17 wherein said formed viscous aqueous
treating fluid is a fracturing fluid or a gravel packing carrier
fluid.
19. The method of claim 17 wherein said environmentally safe
hydrocarbon carrier liquid is selected from the group consisting of
a mixture of hydrocarbons having in the range of from about 6 to
about 13 carbon atoms obtained by treating a petroleum fraction
with hydrogen in the presence of a catalyst, a mixture of
hydrocarbons having in the range of from about 10 to about 25
carbon atoms obtained by catalytic hydrogenation of vacuum gas oils
followed with dewaxing by hydroisomerization and stabilization by
hydrotreating at high pressures, a mixture of severely hydrocracked
low toxicity mineral oils and synthetic isoalkanes, polyalpha
olefins, mixtures of C.sub.10-C.sub.14 alkanes and C.sub.8 and
higher alkenes, mixtures of linear alpha and internal olefins,
hydrocarbon blends containing 93% linear paraffins, blends of
isoalkanes, isoalkenes and alcohols, blends of linear internal
olefins having from about 16 to about 18 carbon atoms, blends of
linear alpha-olefins having 10 or more carbon atoms, vegetable
oils, and vegetable esters.
20. The method of claim 17 wherein said environmentally safe
hydrocarbon carrier liquid is a mixture of hydrocarbons having in
the range of from about 6 to 13 carbon atoms obtained by treating a
petroleum fraction with hydrogen in the presence of a catalyst.
21. The method of claim 17 wherein said environmentally safe
hydrocarbon carrier liquid has a flash point above about
175.degree. F. and a pour point below about -49.degree. F.
22. The method of claim 17 wherein said environmentally safe
hydrocarbon carrier liquid is present in said concentrate in an
amount in the range of from about 25% to about 55% by weight
thereof.
23. The method of claim 17 wherein said organophillic clay
suspending agent is selected from the group consisting of
quaternary ammonium bentonite clay, quaternary ammonium
montmorillonite clay and quaternary ammonium hectorite clay.
24. The method of claim 23 wherein two of the quaternary ammonium
substituents of the organophillic clay are alkyl radicals having in
the range of from 1 to 10 carbon atoms and two of the organic
substituents are alkyl radicals having in the range of from 10 to
30 carbon atoms.
25. The method of claim 17 wherein said organophillic clay
suspending agent is quaternary ammonium bentonite clay.
26. The method of claim 17 wherein said organophillic clay
suspending agent is present in said concentrate in an amount in the
range of from about 0.2% to about 4% by weight thereof.
27. The method of claim 17 wherein said surfactant for dispersing
said organophillic clay suspending agent in said carrier liquid is
selected from the group consisting of amphoteric surfactants,
anionic surfactants, cationic surfactants and nonionic
surfactants.
28. The method of claim 17 wherein said surfactant for dispersing
said organophillic clay suspending agent in said carrier liquid is
selected from the group consisting of nonionic esters, polyethylene
glycol esters, ethoxylated acids, ethoxylated oils, sorbitol
esters, ethoxylated sorbitol esters, ethoxylated alcohols, alcohol
alkoxylates, alkanolamides, quaternary ammonium compounds, dialkyl
quaternary ammonium compounds, benzyl quaternary ammonium
compounds, amine oxides, ethoxylated amines, fatty imidazolines,
ether carboxylates, sulfonates, sulfosuccinates, fatty acid
taurates, ether carboxylates, alkyl betaines, and alkyl amidopropyl
betaines.
29. The method of claim 17 wherein said surfactant for dispersing
said organophillic clay suspending agent in said carrier liquid is
an ethoxylated alcohol.
30. The method of claim 17 wherein said surfactant for dispersing
said organophillic clay suspending agent in said carrier liquid is
present in said concentrate in an amount in the range of from about
0.1% to about 2% by weight thereof.
31. The method of claim 17 wherein said particulate aqueous fluid
gelling agent is selected from the group consisting of guar,
hydroxypropylguar, carboxymethylhydroxypropylguar,
hydroxyethylcellulose, carboxymethylhydroxyethylcellulose,
carboxymethylcellulose, xanthan and succinoglycan.
32. The method of claim 17 wherein said particulate aqueous fluid
gelling agent is guar.
33. The method of claim 20 wherein said particulate aqueous fluid
gelling agent is present in said concentrate in an amount in the
range of from about 25% to about 55% by weight thereof.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to liquid gelling agent
concentrates and methods of treating wells using the
concentrates.
[0003] 2. Description of the Prior Art
[0004] Viscous gelled aqueous treating fluids are used in a variety
of treatments in oil and gas wells including well completions and
production stimulation treatments. An example of a well completion
treatment which utilizes a viscous gelled aqueous fluid is known in
the art as gravel packing. In gravel packing treatments, solid
gravel particles such as sand are carried by way of the well bore
to a subterranean zone in which a gravel pack is to be placed by a
viscous gelled aqueous carrier fluid. That is, particulate solids
(referred to in the art as gravel) are suspended in the viscous
gelled aqueous carrier fluid at the surface and are carried to the
subterranean zone in which the gravel pack is to be placed. Once
the gravel is placed in the zone, the viscous gelled aqueous
carrier fluid is broken (the viscosity is reduced) and recovered
(returned to the surface) by a delayed viscosity breaker in the
carrier fluid. The gravel pack produced functions as a filter to
separate formation solids from produced fluids while permitting the
produced fluids to flow into and through the well bore.
[0005] An example of a production stimulation treatment utilizing a
viscous gelled aqueous fluid is hydraulic fracturing. In hydraulic
fracturing, a viscous gelled aqueous fluid, referred to in the art
as a fracturing fluid, is pumped through the well bore into a
subterranean zone to be stimulated at a rate and pressure such that
fractures are formed and extended into the subterranean zone. The
fracturing fluid also carries particulate solids, referred to in
the art as proppant particles into the fractures. The proppant
particles are suspended in the viscous gelled aqueous fracturing
fluid so that the proppant particles are carried into the
fractures. The viscous fracturing fluid is then broken by a delayed
viscosity breaker in the fracturing fluid so that the proppant
particles are deposited in the fractures and the fracturing fluid
is removed from the subterranean zone. The proppant particles
function to prevent the fractures from closing whereby conductive
channels are formed through which produced fluids can flow to the
well bore.
[0006] The viscous gelled aqueous treating fluids used in gravel
packing, fracturing and other well procedures have heretofore been
prepared by dissolving a dry powdered gelling agent into the vortex
of a vigorously stirred aqueous fluid. This procedure has very
often resulted in undesirable agglomerations of the gelling agent
in the polymer which are called "fish eyes." Fish eyes are polymer
masses wetted on the outside but with dry, unhydrated material
inside. While mechanical gelling agent feeders and adductors have
been utilized to more efficiently wet the gelling agent, the
feeders and adductors often fail to prevent the formation of fish
eyes.
[0007] More recently, storable liquid gelling agent concentrates
have been developed and used. One such liquid gelling agent
concentrate which has been used successfully comprised of
particulate gelling agent which is suspended in a diesel oil
carrier liquid. The particulate gelling agent is rendered
suspendible in the hydrocarbon carrier liquid by a coating of a
suspending agent and a surfactant on the particulate gelling agent.
The particulate gelling agent is then dispersed in diesel oil or
other hydrocarbon liquid to form the liquid gel concentrate. The
liquid gel concentrate can be stored at the well site, and when a
gelled aqueous treating fluid is required, the liquid gelled
concentrate is readily combined with an aqueous fluid without the
formation of fish eyes or other similar problems.
[0008] A problem with the liquid gelling agent concentrates
utilized heretofore which include a hydrocarbon carrier fluid such
as diesel oil is that the hydrocarbon carrier fluid contains
compounds such as benzene, ethylbenzene, toluene, xylene and/or
other compounds which are prohibited by the Environmental
Protection Agency primary drinking water standards, i.e, Section
1429 of the Safe Drinking Water Act. Another problem with such
gelling agent concentrates is that they can not be stored for long
periods of time and they often do not have good pour abilities or
non-settling properties. Thus, there are needs for improved
storable liquid gel concentrates which are environmentally safe and
meet the standards of the Safe Drinking Water Act and have long
term storage, good pour abilities and non-settling properties.
SUMMARY OF THE INVENTION
[0009] The present invention provides storable liquid gelling agent
concentrates that have improved storage, pour abilities and
settling properties and methods of treating wells using the
concentrates. A liquid gelling agent concentrate of this invention
basically comprises an environmentally safe hydrocarbon carrier
liquid, an organophillic clay suspending agent, a surfactant for
dispersing the organophillic clay suspending agent in the
hydrocarbon carrier liquid, and a particulate aqueous fluid gelling
agent suspended in the carrier liquid.
[0010] A method of this invention for treating a subterranean zone
penetrated by a well bore using a viscous aqueous treating fluid is
comprised of the following steps. A liquid gelling agent
concentrate is mixed with an aqueous fluid to thereby form a
viscous aqueous treating fluid. The liquid gelling agent
concentrate comprises an environmentally safe hydrocarbon carrier
liquid, an organophillic clay suspending agent, a surfactant for
dispersing the organophillic clay suspending agent in the carrier
liquid, and a particulate aqueous fluid gelling agent suspended in
the carrier liquid. The viscous aqueous treating fluid is
introduced into a subterranean zone to be treated.
[0011] The liquid gelling agent concentrate of this invention can
be utilized in a variety of subterranean zone treatments such as
fracturing subterranean zones, placing gravel packs in subterranean
zones, and the like. The hydrocarbon carrier of the liquid gelling
agent concentrate is an environmentally safe hydrocarbon liquid
that meets the standards set forth in the Safe Drinking Water Act
and does not include hazardous chemicals such as benzene,
ethylbenzene, toluene or xylene. The hydrocarbon carrier liquid
utilized in the liquid gelling agent concentrate can carry up to
five pounds of gelling agent per gallon of the concentrate. The
liquid gelling agent concentrate has a high flash point and a low
pour point. In addition, the liquid gelling agent concentrate can
be stored for long periods of time, has good pour abilities and
settling properties and is easily combined with water to form a
viscous gelled aqueous treating fluid.
[0012] The objects, features and advantages of the present
invention will be readily apparent to those skilled in the art upon
a reading of the description of preferred embodiments which
follows.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0013] The present invention provides improved liquid gelling agent
concentrates and methods of treating wells using the concentrates.
The liquid gelling agent concentrates comprise an environmentally
safe hydrocarbon carrier liquid, an organophillic clay suspending
agent, a surfactant for dispersing the organophillic clay
suspending agent in the carrier liquid, and a particulate aqueous
fluid gelling agent suspended in the carrier liquid. The liquid
gelling agent concentrates can be stored for long periods of time
and they have good pour abilities and non-settling properties.
[0014] The methods of this invention for treating a subterranean
zone penetrated by a well bore using a viscous aqueous treating
fluid comprises the following steps. A liquid gelling agent
concentrate of this invention is mixed with an aqueous fluid to
thereby form a viscous aqueous treating fluid. Thereafter, the
viscous aqueous treating fluid is introduced into the subterranean
zone.
[0015] An example of an environmentally safe hydrocarbon carrier
liquid that can be utilized in accordance with this invention is a
mixture of hydrocarbons having in the range of from about 6 to
about 13 carbon atoms obtained by treating a petroleum fraction
with hydrogen in the presence of a catalyst. This mixture of
hydrocarbons is commercially available under the trade designation
"ENVIRONDRILL.TM." from Wells Cargo Oilfield Services of Calgary,
Alberta, Canada. Another example is a mixture of hydrocarbons
having in the range of from about 10 to about 25 carbon atoms
obtained by catalytic hydrogenation of vacuum gas oils followed
with dewaxing by hydroisomerization and stabilization by
hydrotreating at high pressures. This mixture of hydrocarbons is
commercially available under the trade name "PURE DRILL IA-35.TM."
which is commercially available from Petro-Canada of Mississauga,
Ontario, Canada. Yet another example is a mixture of severely
hydrocracked low toxicity mineral oils and synthetic isoalkanes.
This hydrocarbon mixture is commercially available under the trade
designation "PURE DRILL HT-40" from Petro-Canada of Mississauga,
Ontario, Canada.
[0016] Other environmentally safe hydrocarbons that can be utilized
as carrier liquids in accordance with this invention include, but
are not limited to, mixtures of linear alpha and internal olefins;
polyalpha olefins; mixtures of C.sub.10-C.sub.1-4 alkanes and
C.sub.8 and higher alkenes; mixtures of linear alpha and internal
olefins; hydrocarbon blends containing 93% linear paraffins; blends
of isoalkanes, isoalkenes and alcohols; blends of linear internal
olefins having from about 16 to about 18 carbon atoms; blends of
linear alpha-olefins having 10 or more carbon atoms; vegetable
oils; and vegetable esters.
[0017] Of the foregoing environmentally safe hydrocarbon carrier
liquids, a mixture of hydrocarbons having in the range of from
about 6 to about 13 carbon atoms obtained by treating a petroleum
fraction with hydrogen in the presence of a catalyst is preferred.
This carrier liquid has a flash point above about 175.degree. F.
and a pour point below about -49.degree. F.
[0018] The hydrocarbon carrier liquid utilized is generally present
in the liquid gelling agent concentrate in an amount in the range
of from about 25% to about 55% by weight of the concentrate.
[0019] A variety of organophillic clay suspending agents can be
utilized in the liquid gelling agent concentrate. Generally,
organophillic clays which are formed by reacting quaternary
ammonium salts with water swellable clays are preferred. The
quaternary ammonium salts utilized are preferably those wherein the
quaternary ammonium substituents are alkyl radicals, two of which
have in the range of from 1 to 10 carbon atoms and the other two
having in the range of from 10 to 30 carbon atoms. The most
preferred organophillic clays for use in accordance with the
present invention include, but are not limited to, quaternary
ammonium bentonite clay, quaternary ammonium montmorillinite clay
and quaternary ammonium hectorite clay. Of these, quaternary
ammonium bentonite clay is the most preferred. The organophillic
clay utilized is included in the liquid gelling agent concentrate
in an amount in the range of from about 0.2% to about 4% by weight
of the concentrate.
[0020] Examples of surfactants that can be used for dispersing the
organophillic clay suspending agent in the carrier liquid include
amphoteric surfactants, anionic surfactants, cationic surfactants
and nonionic surfactants. Examples of specific such surfactants
include, but are not limited to, nonionic esters, polyethylene
glycol esters, ethoxylated acids, ethoxylated oils, sorbitol
esters, ethoxylated sorbitol esters, ethoxylated alcohols, alcohol
alkoxylates, alkanolamides, quaternary ammonium compounds, dialkyl
quaternary ammonium compounds, benzyl quaternary ammonium
compounds, amine oxides, ethoxylated amines, fatty imidazolines,
ether carboxylates, sulfonates, sulfosuccinates, fatty acid
taurates, ether carboxylates, alkyl betaines, and alkyl amidopropyl
betaines. Of the foregoing surfactants, ethoxylated alcohol is
generally preferred. The surfactant utilized is included in the
liquid gelling agent concentrate in an amount in the range of from
about 0.1% to about 2% by weight of the concentrate.
[0021] Any of a variety of particulate gelling agents can be
utilized in accordance with the present invention. The gelling
agents generally include a water dispersable or water soluable
hydrophilic colloid such as cellulose derivatives, starch
derivatives, gums including ghatti, Arabic, tragacanth, locust
bean, karaya, carrageenan, algin, and derivatives of such gums,
biopolymers and mixtures thereof. Examples of preferred particulate
aqueous fluid gelling agents for use in accordance with the present
invention include, but are not limited to, guar, hydroxypropylguar,
carboxymethylhydroxyproplyguar, hydroxyethylcellulose,
carboxymethylhydroxyethylcellulose, carboxymethylceullose, xanthan
and succinoglycan. Of these, guar is the most preferred. The
particulate aqueous fluid gelling agent utilized is generally
present in the liquid gelling agent concentrate in an amount in the
range of from about 25% to about 55% by weight of the concentrate,
i.e., up to and including 5 pounds of gelling agent per gallon of
the concentrate.
[0022] As mentioned, the liquid gelling agent concentrates of this
invention preferably include environmentally safe hydrocarbon
carrier liquids that meet the standards set forth in the
Environmental Protection Agency Safe Drinking Water Act. As also
mentioned, the liquid gelling agent concentrates can contain
particulate aqueous fluid gelling agents in amounts up to five
pounds of particulate aqueous fluid gelling agent per gallon of the
concentrates and higher. Also, the preferred liquid gelling agent
concentrates of this invention have higher flash points than the
heretofore utilized liquid gel concentrates, i.e., flash points as
high as 175.degree. F. and pour points that are lower than the
heretofore used concentrates, i.e., -49.degree. F. and lower.
[0023] The liquid gelling agent concentrates of this invention have
long term storage, good pour abilities and non-settling properties.
For example, the preferred liquid gelling agent concentrates of
this invention can be stored for seven days at 80.degree. F.
without significant settling of the particulate gelling agent
therein and less than 2% free liquid.
[0024] A preferred liquid gelling agent concentrate of this
invention comprises: an environmentally safe hydrocarbon carrier
liquid; an organophillic clay suspending agent; a surfactant for
dispersing the organophillic clay suspending agent in the carrier
liquid; and a particulate aqueous fluid gelling agent suspended in
the carrier liquid.
[0025] Another preferred liquid gelling agent concentrate
comprises: an environmentally safe hydrocarbon carrier liquid
comprising a mixture of hydrocarbons having in the range of from
about 6 to about 13 carbon atoms obtained by treating a petroleum
fraction with hydrogen in the presence of a catalyst present in an
amount in the range of from about 25% to about 55% by weight of the
concentrate; a quaternary ammonium bentonite clay suspending agent
present in an amount in the range of from about 0.2% to about 4% by
weight of the concentrate; an ethoxylated alcohol surfactant
present in an amount in the range of from 0.1% to about 2% by
weight of the concentrate; and a guar particulate aqueous fluid
gelling agent present in an amount in the range of from about 25%
to about 55% by weight of the concentrate.
[0026] A preferred method of this invention for treating a
subterranean zone penetrated by a well bore using a viscous aqueous
treating fluid comprises the steps of: (a) mixing a liquid gelling
agent concentrate with an aqueous fluid to thereby form a viscous
aqueous gelled treating fluid, the liquid gelling agent concentrate
comprising an environmentally safe hydrocarbon carrier liquid, an
organophillic clay suspending agent, a surfactant for dispersing
the organophillic clay suspending agent in the carrier liquid, and
a particulate aqueous fluid gelling agent suspended in the carrier
liquid; and (b) introducing the viscous aqueous gelled treating
fluid into the subterranean zone.
[0027] Another preferred method of treating a subterranean zone
penetrated by a well bore using a viscous aqueous treating fluid
comprises the steps of: (a) mixing a liquid gelling agent
concentrate with an aqueous fluid to thereby form a viscous gelled
aqueous treating fluid, the liquid gelling agent concentrate
comprising an environmentally safe hydrocarbon carrier liquid that
comprises a mixture of hydrocarbons having in the range of from
about 6 to about 13 carbon atoms obtained by treating a petroleum
fraction with hydrogen in the presence of a catalyst present in an
amount in the range of from about 25% to about 55% by weight of the
concentrate, a quaternary ammonium bentonite clay suspending agent
present in an amount in the range of from about 0.2% to about 4% by
weight of the concentrate, an ethoxylated alcohol surfactant
present in an amount in the range of from about 0.1% to about 2% by
weight of the concentrate, and a guar particulate aqueous fluid
gelling agent present in an amount in the range of from about 25%
to about 55% by weight of the concentrate; and (b) introducing the
viscous aqueous treating fluid into the subterranean zone.
[0028] In order to further illustrate the liquid gelling agent
concentrate and methods of this invention, the following examples
are given.
EXAMPLE 1
[0029] A liquid gelling agent concentrate of this invention
(referred to herein as "Inventive Concentrate") was prepared in the
laboratory comprising 43% by weight of diesel oil, 1% by weight of
a quaternary ammonium bentonite clay suspending agent, 1% by weight
of an ethoxylated alcohol surfactant for dispersing the suspending
agent, and a 55% by weight of a guar particulate gelling agent.
[0030] A prior art gelling agent concentrate (referred to herein as
"Concentrate A") published by Union Carbide Corporation was also
prepared comprising 53.83% by weight diesel oil, 1.39% by weight
organophillic clay, 0.28% by weight methanol, 42.5% by weight
hydroxyethylcellulose and 2.0% nonylphenol surfactant.
[0031] Each of the above described liquid gelling agent
concentrates was placed in an 80.degree. F. water bath and after
time intervals of 24 hours, 48 hours, 72 hours and 168 hours, the
percent of free liquid separation and the settling of solids in the
concentrates were observed.
[0032] The results of these tests are given in Tables I and II
below.
1TABLE I % Free Liquid Separation 168 hours 24 hours 48 hours 72
hours (7 days) Concentrate at 80.degree. F. at 80.degree. F. at
80.degree. F. at 80.degree. F. Inventive 0 0 0 1.4 Concentrate
Concentrate A 2.1 2.3 2.4 2.4
[0033]
2TABLE II Settling of Solids 168 hours 24 hours 48 hours 72 hours
(7 days) Concentrate at 80.degree. F. at 80.degree. F. at
80.degree. F. at 80.degree. F. Inventive 0 0 0 0 Concentrate
Concentrate A 0 trace Ring.sup.1 Ring.sup.1 .sup.1Ring means the
presence of solids in the bottom of the container forming a
ring.
[0034] From Tables I and II, it can be seen that the Inventive
Concentrate can be stored for at least seven days at 80.degree. F.
without settling and with less than 2% free liquid.
EXAMPLE 2
[0035] Samples of the Inventive Concentrate and Concentrate A
described in Example 1 as well as two other prior art concentrates
designated "Concentrate B" and "Concentrate C" were tested for
viscosity using a Brookfield viscometer equipped with a number 3
spindle at 20 rpm and at a temperature of 80.degree. F.
[0036] Concentrate B was prepared comprising 49% by weight of
diesel oil, 5% by weight of an aqueous emulsion of a suspending
agent comprising water insoluble polymer particles that swell when
contacted with diesel oil and 46% by weight of polysaccharide water
soluble gelling agent. This concentrate is described in detail in
U.S. Pat. No. 4,772,646 issued to Harms, et al. on Sep. 20, 1988
which is incorporated herein by reference thereto.
[0037] Concentrate C published by Hercules, Inc. was prepared
comprising 37% by weight of hydroxyethylcellulose, 40.1% by weight
of an ethyl hexanol premix containing 1% hydroxypropylcellulose,
21.1% by weight of mineral oil and 1.8% by weight of an ethoxylated
alcohol surfactant.
[0038] The results of these tests are given in Table III below.
3 TABLE III Viscosity, cP Samples Inventive Tested Concentrate A
Concentrate B Concentrate C Concentrate 1 960 3008 3904 650 2 512
4736 4352 780 3 1088 4608 4928 850 4 -- -- 5632 860 5 -- -- 4736
852
[0039] From Table III, it can be seen that the Inventive
Concentrate has the lowest viscosity which provides excellent pour
ability.
[0040] Thus, the present invention is well adapted to carry out the
objects and attain the ends and advantages mentioned as well as
those which are inheritant therein. While numerous changes can be
made by those skilled in the art, such changes are encompassed
within the spirit of this invention as defined by the appended
claims.
* * * * *