Note: Descriptions are shown in the official language in which they were submitted.
COMPOSITION OF ORGANIC GEL FORMULATIONS FOR ISOLATION OF HIGH
TEMPERATURE AND SALINITY PETROLEUM RESERVOIR ZONES
DESCRIPTION
FIELD OF INVENTION
The present invention describes an organic gel formulation composition for the
blocking of
naturally fractured carbonate reservoir fluids at salinity conditions up to
31,870.50 ppm of
total dissolved solids and temperatures until 120 C, that is in order to
temporally isolate
reservoir areas that will be treated with chemical and radioactive products
for quantification
of remaining oil in them, the stability of the gel is controlled in a certain
period of time,
through the synergic effect of the supramolecular interaction between the
components of
the gel formulation.
BACKGROUND OF INVENTION
A gel is a colloidal system where the continuous phase is solid, and the
dispersed
phase is liquid. The gels have a similar density to liquids; however, their
structure resembles
much more solids. The most common example of gel is edible gelatin. They have
a wide
application field at industrial level. In oil industry, the use of gels has
been extended to
naturally fractured reservoirs and its main application has been in
conformance control,
enhanced recovery processes, as well as permeability modifiers, such as
diverging, fracture
sealants for hydraulic fracturing and as isolators. In these applications, the
stability of the
gel plays an extremely important role and it depends on the chemical structure
of the gel,
in addition to the conditions of temperature, pressure and salinity that are
held in the
reservoir.
Nowadays, the use of polymer-based gels is one of the main chemical methods
used
in the oil industry. Most gels reported in literature are polyacrylamide base
or acrylamide-
based copolymers with inorganic or organic cross-linkers such as Cr (III) (i),
Al (III) salts,
among others, used to form an inorganically cross-linked gelled system; these
gels are the
result of the ionic bond between the negatively charged carboxylate groups and
the positive
charge of the polyvalent ions (ii). However, the formation time of the most
used gelled
systems such as chromium (III) acetate /partially
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Date Recue/Date Received 2021-04-12
hydrolyzed polyacrylamide (PHPAM) is approximately only 5 hours at 40 C,
which is
insufficient to place the gel in the bottom of the formation in wells with too
deep production
intervals. Procedures have been reported to increase gel formation time by
using stronger
cross linkers such as malonate and glycolate (iii) anions, to make their
placement possible,
however, the loss of consistency could also occur when the binding with Cr
(Ill)) becomes
too strong, in addition to the ionic bonds being unstable at temperatures
higher than 70 C
(iv).
Organic cross-linkers have been used to obtain gels that are stable in
reservoirs with a
temperature range greater than 90 C, however, at temperatures above 100 C,
the
polyacrylamide base polymers present hydrolysis as a consequence of the
oxidative
degradation of the polymer chains (v), this coupled with the presence of
polyvalent ions in
the medium, promotes the expulsion of water from the structure of the gel,
which is known
as syneresis.
Unlike inorganic cross-linkers, the gelation mechanism of organic cross-
linkers is
through covalent bonds, which are by far more stable than the ionic bond.
Acrylamide base
copolymers with organic crosslinking agents, such as phenol formaldehyde, can
be used to
form a gel with thermal stability and adjustable gelation time (vi), however
there is
controversy regarding its toxicity. Hardy and others report the use of a
system of low toxicity
formed by a copolymer of acrylamide and terbutil acrylate (PAtBA), with
polyethyleneimine
(PEI) as a cross linking agent, it is stable at high temperatures, however
there are serious
complications in its placement and use due mainly to its rapid cross linking
kinetics that in
a certain proportion can be controlled with the use of salts that provide the
medium with
monovalent ions that retard crosslinking, as well as its consistency too
rigid, besides being
prohibitive due to the high cost of the cross linker (vii). ) (viii). Among
the most recently used
methods is the secondary cross linking method, which can also increase gel
strength and
improve its strength, using more than one crosslinking agent acting in a first
step to facilitate
the placement of the system and subsequently the second cross linker, will
give the
definitive consistency at the bottom of naturally fractured reservoirs (ix).
As it has been shown, the treatment with gelling polymeric systems has been
widely
implemented to improve the efficiency of volumetric sweeping in reservoirs or
to reduce the
excessive water production, among others.
The patents recognized by the applicant, which protect the main chemical
families of
the materials used to generate the gel and the use respectively, are:
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CA 3049363 2019-07-09
a) U.S. Patent No. 5,905,100 describes the gelation of acrylamide contained
in a
polymer with hexamethylenetetramine and an aminobenzoic acid or phenol
compound, as
a permeability reducer. Ahmad Morandi - Araghi., Relates the gelation of a
water-soluble
polymer with an organic cross-linking agent used in hydrocarbon field
operations. It provides
a less toxic environment in its system of cross-linking, reducing permeability
at high
temperature of formation, by means of a system formed by a noble cross-linker
and a water-
soluble polymer, composed of hexamethylenetetramine, a cross-linker,
aminobenzoic acid
and phenol and a water-soluble acrylamide polymer.
b) US Pat. No. 6,465,397 B1 refers to solutions of water-soluble copolymers
used
to modify the permeability of water in hydrocarbon-producing underground
formations. The
copolymer comprises copolymerized synthetic cross-linker, which has an intra
and inter
molecular balance, which can be injected. Being a homogeneous aqueous solution
of
copolymerized amide acrylic and a vinyl sulfonated co-monomer and a quantity
of non-ionic
cross-linker.
c) In US Patent 4507440, Friedrich Engelhardt, Steffen Piesch, Juiane
Balzer and
Jeffery C. Dawson, discuss the water-soluble polymers used in the improved oil
recovery,
which are cross-linked by adding an acid. These polymers are used in acid
stimulations in
oil and gas reservoirs. The polymers contain co-polymerized acrylamide and co-
monomers
of the formyl-amido type. The content of HCI in the mixture of the water-
soluble copolymer
such as the copolymer 2-acrylamido-2-methylpropanesulfonic acid-acrylamido-N-
vinyl-N-
methylacetamide and another as the copolymer acrylic acid-vinyl formamido-
vinyl
pyrrolidone. The cross-linked gels are stable on days at 20-30 C in an acid
medium but
there are easily hydrolyzed at 80-90 C.
d) In
US Patent No. 4,718,491, Norbert Kholer talks about the use of
polysaccharides, which are difficult to inject into porous spaces to slow or
reduce the water
inflow, but they allow an incomplete exploitation in the oil reservoirs. Its
effect is lost at high
temperatures.
e) In US patent US 4095651, Guy Chauveteau discusses the use of hydrolyzed
polyacrylamide. In this type of polymers, it is more effective for water with
low salt content,
degrading rapidly with the increase of salts, with the presence of polyvalent
ions, these
polymers have a tendency to form precipitates at high temperatures that can
close the pores
of the formation rocks.
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Date Recue/Date Received 2021-04-12
f)
Patent EP 2126016 A2, mentions an aqueous base insulating fluid comprising
an aqueous base fluid, a water miscible organic liquid and a synthetic
polymer, optionally a
crosslinking agent is added to the mixture comprising the synthetic polymer to
crosslink the
same, the mixture comprising the synthetic polymer can be placed in a selected
location,
allowing the mixture comprising the synthetic polymer is activated to form a
gel there.
In none of the aforementioned references is claimed, the development of
composition
of organic gel formulations for the blocking of fluids in naturally fractured
carbonate
reservoirs, for salinity conditions up to 31,870.50 ppm of total dissolved
solids and
temperatures up to 120 C, in order to isolate temporarily zones of
reservoirs that will be
treated with chemical and radioactive products in order to quantify the oil
remaining in them.
It is, therefore, the object of the present invention, is to provide a
composition of high
temperature and salinity organic gel formulations for isolating oil reservoir
zones. This
invention relates to the formulation of two organic insulating fluids for
temporary blockage
in naturally fractured carbonates reservoirs, for salinity conditions
(31,870.50 ppm of total
dissolved solids) and temperature (120 C), in order to control the stability
of the gel in a
certain period of time (considering 24 hours of placement, 8 weeks of
permanence to
subsequently degrade ), through the synergistic effect of the organic cross-
linking
interaction between the components of the formulation, in order to isolate an
area from the
reservoir rock for a control volume injection.
BRIEF DESCRIPTION OF THE DRAWINGS OF THE INVENTION
In order to have a greater understanding regarding the composition of high
temperature
and salinity organic gel formulations to isolate oil reservoirs zones of the
present invention,
the following, the contents of the accompanying drawings are briefly
described:
Figure 1 shows, the resistance to inversion of the formulation described in
Example 1 at
120 C as a function of time, according to the description developed by
Robert Sydanks
(1988).
Figure 2. Illustrates the resistance to inversion of the formulation described
in Example 2 at
120 C as a function of time, according to the description developed by
Robert Sydanks
(1988).
Figure 3 shows, a graph of the behavior of the viscosity with respect to the
shear rate for
the formulation of Example 1 at 21 C.
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CA 3049363 2019-07-09
Figure 4 shows, a graph of the behavior of the shear stress with respect to
the shear rate
for the formulation of Example 1 at 21 C.
Figure 5 shows, a graph of the behavior of the viscosity with respect to the
shear rate for
the formulation of Example 2 at 21 C.
Figure 6 shows, a graph of the behavior of the shear stress with respect to
the shear rate
for the formulation of Example 2 at 21 C.
Figure 7 shows, a diagram of the viscosity measuring equipment for the
determination of
the rheological model. Where V-1, V-2, V-3, V-6, V-7, V-11, V-10, V-14 and V-
15 are high
pressure needle valves, BPR is a Back Pressure Regulator, and numbers 1 to 7
are the
equipment number in the process of the measuring viscosity.
Figure 8 illustrates the Rheological model of the gellant formulation
described in Example
1 for shear rate ranges from 10 to 70 [1 / s].
Figure 9 shows the Rheological model of the gelling formulation, of the
formulation
described in example 1 for shear rate ranges from 600 to 1000 [1/ s].
Figure 10 shows, flow curves at different residence times of the formulation
described in
example 1.
Figure 11 shows viscosity curves at different residence times of the
formulation described
in example 1.
Figure 12 presents a graph of the elastic modulus versus time of the
formulation described
in example 1.
Figure 13 presents a graph of the viscous modulus versus time of the
formulation described
in example 1.
Figure 14 illustrates a graph of Damping factor versus time of the formulation
described in
example 1.
Figure 15 shows, flow curves at different residence times of the formulation
described in
example 2.
Figure 16 shows, viscosity curves at different residence times of the
formulation described
in example 2.
Date Recue/Date Received 2021-04-12
Figure 17 presents a graph of the elastic modulus versus time of the
formulation described
in example 2.
Figure 18 presents a graph of the viscous modulus versus time of the
formulation described
in example 2.
Figure 19 illustrates a graph of Damping factor versus time of the formulation
described in
example 2.
Figure 20 illustrates a comparative graph of the inversion resistance of the
formulations
described in Example 1 and Example 2 at different salinities.
DETAILED DESCRIPTION OF THE INVENTION
The present invention involves a composition of organic gel formulations for
the
blocking of fluids in carbonated naturally fracture reservoirs, having a
stabilizing effect for a
gelation system at high temperature of 120 C and 31,870.5 ppm dissolved total
solids of
salinity as NaCI, this gelation system to serve as a barrier between the
formation water and
injected fluid , in order to isolate the reservoir zone and facilitate the
quantification of the
remaining oil by means of tracers in carbonated naturally fracture reservoirs
at high
temperature and salinity condition, considering 24 hours of placement, and 8
weeks of
permanence ,to finally degrade.
The composition of the present invention can be used where is compatibility
with the
congenital water of the carbonated naturally fracture reservoir, in addition,
it also works
properly where a production assurance or improved oil recovery process is
carried out and
can be supplied through an injector producer well (figure 20).
For the development processing of the present invention the following
procedure was
followed: I. Evaluation of the stability of the gelling formulation at
temperature conditions
120 C; II. Characterization of the gelling formulation a) Measurement of the
viscosity
(21 C) and b) Determination of the Rheological Model of the gelling
formulation at average
reservoir condition , pressure 2,000 psi ant temperature 120 C; and III.
Monitoring the
progress of cross linking and permanence of the gelling formulation at 30 C
and
atmospheric pressure, using rheological tests.
Examples
Some examples are given below of the application of organic gel formulations
composition
for blocking of fluids in carbonated naturally fracture reservoirs, in
accordance with the
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Date Recue/Date Received 2021-04-12
present invention, it being understood that said examples are illustrative
only and are not
intended to limit the scope of the present invention.
I. Evaluation of the stability gallant formulation at 120 C.
The evaluation of the stability gelling formulation consisted in evaluating
different chemical
products based on polyacrylamides in an air convection oven at a temperature
of 120 C
and using the code development by Robert Sydanks in 1988, to evaluate the
qualitative
variation of the behavior of the apparent viscosity.
Example 1. In a 100 ml flask equipped with a magnetic stirrer, it is diluted
at room
temperature and atmospheric pressure, 0.3% weight of copolymer of acrylamide
butyl
tertiary sulfonic acid (ATBS) and acrylamide, 0.12% weight of phenol and 0.18%
weight of
hexamethylenetetramine in 99.4% weight of reservoir brine with a total solids
content of
31,870.50 ppm. The figure 1 shows, the behavior of the code developed by R.
Sydanks
(1988), of the aforementioned formulation at 120 C as a function of time,
prepared with
brine at 0.3% weight of the polyacrylamide described above, 0.12% weight of
phenol and
0.18% weight of hexamethylenetetramine, it is observed that the formation of
gel begins at
24 hours maintaining its maximum rigidity for 648 hours and from this moment
the
degradation of the gel begins.
According to the table of resistance to the inversion movement in a glass
tube,
development by Robert Sydanks in 1988, Table 1, it qualitatively indicates the
change in
the resistance to movement of the gel in a fraction time.
In figure 1. It shows the advance in the gel strength of the formulation
described as a
function time, for 22 hours the Sydanks code is 1, indicating that the
solution has the same
apparently viscosity (fluidity) as the polymeric solution, increasing from 24
hours to 3, it
indicates a detectable gel that flows to the surface of the container under
immersion. After
144 hours, the Sydanks code is increased from code3 to code 8 in 192 hours.
The code 8
indicates the formation of a slightly deformable gel. After this time and up
to approximately
648 hours, the code 8 is maintained. Finally, the degradation starts from this
moment, as
shown in figure 11.
Example 2. In a 100 ml bottle equipped with a magnetic stirrer, 1.0% weight of
sulfonic
acid copolymer of tertiary butyl acrylamide (ATBS) and acrylamide, 0.4% weight
of phenol
and 0.6% weight of hexamethylenetetramine diluted at room temperature and
atmospheric
pressure, in 98 weight of reservoir brine with a total solids content of
31,870.50 ppm. In
figure 2, the behavior of the code developed by Synanks (1988) of the
aforementioned
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Date Recue/Date Received 2021-04-12
formulation at 120 C as a function of time is shown; this is prepared with
1.0% by weight
brine of the polyacrylamide described above, 0.4% weight of phenol. and at
0.6% weight of
the hexamethylenetetramine, it is observed that the formation of the gel
begins at 24 hours
and maintaining its maximum rigidity during 672 hours and is from this moment
starts the
degradation of the gel.
According to the table of the inversion resistance of movement in the glass
tube,
developed by Robert Sydanks in 1988, Table 1. Indicates the qualitative way to
change the
resistance movement of the gel in fraction time.
In figure 2, the advance of the gel of resistance of the formulation is shown,
previously
described as a function of time, during the first 24 hours, the code of
Sydanks is 8, which
indicates the formation of a slightly deformable gel and after of 96 hours the
code is 10, this
indicates The formation gel is rigid. At this time, the degradation begins as
shown in Figure
16.
II. Characterization of the gel formulation.
a) Viscosity measurement (21 C). The viscosity was determined in the FANNTM
(11) 35A viscometer for the formulation described in example 1 and example 2,
which is
described in example 3 and example 4.
Example 3. For the development of the measurement of viscosity a solution was
prepared as described in Example 1, the results obtained are shown in Figure
3, which
shows the behavior of the viscosity with respect to the shear rate for the
formulation of
example 1, in Figure 4, the behavior of the shear stress with respect to the
shear rate for
the formulation of example 1 at 21 C is presented, after the analysis of the
results it was
obtained that at room temperature it behaves as Pseudoplastic fluid or
ShearThinning , this
indicates that when this kind of fluid is subjected to shear stress, a
variation of the viscosity
is caused. The stronger the effort, the higher its viscosity to the point
where the fluid offers
great resistance to movement.
Example 4. For the development of the measurement of viscosity a solution was
prepared as described in Example 2, the results obtained are shown in Figure
5, which
shows the behavior of the viscosity with respect to the shear rate for the
formulation of
example 2, in Figure 6, the behavior of the shear stress with respect to the
shear rate for
the formulation of example 1 at 21 C is presented, after the analysis of the
results it was
obtained that at room temperature it behaves as Pseudoplastic fluid or
ShearThinning , this
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Date Recue/Date Received 2021-04-12
indicates that when this kind of fluid is subjected to shear stress, a
variation of the viscosity
is caused. The stronger the effort, the higher its viscosity to the point
where the fluid offers
great resistance to movement.
Table 1. Description of the resistance to inversion movement developed by
Robert Sydaks,
(X)
Code Equivalent Definition Description
The gel appears to have the same viscosity (fluidity)
No detectable gel
A 1 as the originalformed
polymer solution and no gel is visually
detectable.
The gel appears to be only slightly more viscous (less
2 Highly flowing gel
fluid) than the initial polymer solution.
Most of the obviously detectable gel flows to the
3 Flowing gel
bottle cap upon inversion.
Only a small portion (about 5 to 12%) of the gel does
not readily flow to the bottle cap upon inversion
Moderately flowing
4 usually characterized as a tonguing gel
(i.e., after
gel
hanging out of jar, gel can be made to flow back into
bottle by slowly turning bottle upright).
The gel can barely flow to the bottle cap and/or a
Barely flowing gel significant portion (>15%) of the gel does not flow
upon inversion.
6 Highly deformable .. The gel does not flow to the bottle
cap upon inversion.
not flowing gel
Moderately The gel flows about half way down the
bottle upon
7 deformable not inversion.
flowing gel
8 Slightly deformable The gel surface only slightly deforms upon
inversion.
not flowing gel.
9 Rigid gel There is no gel-surface deformation upon
inversion
A tuning-fork-like mechanical vibration can be felt
Ringing rigid gel
after tapping the bottle.
b) Rheological model determination for example 1 at average reservoir
conditions, pressure 2000 psi and temperature 120 C. The gelato injection
system at
average reservoir condition: 120 C and 2000 psi, for application as fluid
blockage is shown
in figure 7 (Diagram of the viscosity measuring equipment for the
determination of the
rheological model), which consists of two cylinders of stainless steel with a
capacity of 1,000
ml. this stores the solution gel to be used and another gellant used solution,
and a stainless
steel capillary, which has the following instrumentation: A) Differential
pressure sensor, B)
Pressure sensors, C) Temperature sensor and D) Computer for data analysis.
In this way, the gel injection procedure is as follows: A) Prepare the gel
solution and fill
the storage cylinder, B) Bring the system to the experimental temperature and
monitor it by
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Date Recue/Date Received 2021-04-12
means of the temperature sensor, C) Opening of the sensor valves, which
determines the
differential pressure, D) Injection of the gelling formulation for the filling
the lines, controlling
the system with the pressurized pump, E) Determine the parameters
(differential pressure,
cutting force, cutting speed and Newtonian viscosity) necessary for the
determination of the
rheological model.
Example 5. Determination of the rheological model of the gellant formulation
described
in example 1. The shear rate intervals at which the experimental viscosity
measurements
were made from 10 to 70 (1 Is), the rate from which were obtained the
differentials pressure
and shear rate are show in table 2, with the experimental data proceeds to the
determination
of the rheological model. For the case of the behavior of this fluid, it is
observed that it has
a behavior as a pseudoplastic fluid, for which the experimental data was
adjusted to a power
law method. With the equation shown in Figure 8, it is possible to calculate
data that were
not obtained experimentally, it is worth mentioning that this equation is
valid only for a set
shear rate, for this particular case from 10 to 70 [1 / s], below or above
this interval another
viscosity equation must be obtained. In Figure 9, the q and K parameters of
the power law
model are observed, adjusting the experimental values.
Example 6. Determination of the rheological model of the gellant formulation
described
in example 1. The shear rate intervals at which the experimental viscosity
measurements
were made from 600 to 1,000 [1 / s], the rate from which were obtained the
differentials
pressure and shear rate are shown in Table 3, with the experimental data
proceeds to the
determination of the rheological model. For the case of the behavior of this
fluid, it is
observed that it has a behavior as a pseudoplastic fluid, for which the
experimental data
was adjusted to a power law method. With the equation shown in Figure 9, it is
possible to
calculate data that were not obtained experimentally, it is worth mentioning
that this
equation is valid only for a set shear rate, for this particular case from 600
to 1,000 [1 / s],
below or above this interval another viscosity equation must be obtained. In
Figure 9, the q
and K parameters of the power law model are observed, adjusting the
experimental values.
Table 2. Differential experimental pressure at shear rate from 10 to 70 (1/s)
for
determination of the rheological model
Date Recue/Date Received 2021-04-12
Differential
Rate Shear rate Shear stress Viscosity
Pressure
Q[cm3/h] y[1/s] T[Pa] n [cP]
AP [bar]
0.5372 10.0665 1.0164 100.9718
1.3205 20.0293 2.6019 124.7289
1.8534 30.0439 3.5065 116.7137
1.5337 40.0586 2.9017 72.4364
1.5821 50.0214 2.9932 59.8376
1.9899 59.9841 3.7648 62.7629
1.8229 70.0506 3.4489 49.2340
III. Monitoring of the crosslinking and permanence of the gelling formulation
at
30 C and atmospheric pressure, by rheological tests.
The analysis of the flow curve, viscosity curve, Damping Factor, elastic
modulus and
viscous modulus in Anton PaarTM (12) rheometer model MCR501 at different dwell
times,
analyzed with the concentric cylinder geometry, 50 mm diameter parallel plate
and Hollow
Cylinder at 30 C, atmospheric pressure and shear rate (1 / s): 0.1-1,000.
Example 7. To determine the flow curve, a gel solution was prepared as
described in
Example 1, the results obtained are shown in Figure 10 (Flow curves at
different residence
times of the formulation described in Example 1), when observing the graph of
the shear
stress with respect to the shear rate, we have a fluid with pseudoplastic
behavior.
Example 8. To determine the viscosity curve, a gel solution was prepared as
described
in Example 1, the results obtained are shown in Figure 11 (Viscosity curves at
different
residence times of the formulation described in Example 1 ), when observing
the different
viscosity curves, it dependents on the shear stress in different residence
times of the gel
sample, this is a pseudoplastic behavior, indicated that this material is
submitted to the
shear rate and decrease viscosity.
Table 3. Differential experimental pressure at shear rate from 600 to 1000
(1/s) for
determination of the rheological model.
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Differential
Rate Shear rate Shear stress Viscosity
Pressure
Q[cm3/h] y[1/s] T[Pa] n [cP]
AP [bar]
600 2.3571 622.6724 4.4595 7.1618
715 2.9678 742.0180 5.6149 7.5670
800 3.2325 830.2299 6.1156 7.3662
900 3.5167 934.0086 6.6533 7.1234
1000 3.2827 1037.7874 6.2105 5.9844
Example 9. To determine the modulus of elasticity or also known as storage
modulus
[G'], which indicates how much deformation energy is stored during a cutting
process, a gel
solution was prepared as described in Example 1, The results obtained are
shown in Figure
12 (Graph of the elastic modulus as a function of time for the formulation
described in
Example 1), observing the increase of the elastic modulus in time according to
the scheme
of residence time required for this gel.
Example 10. To determine the viscous modulus or also known as the loss modulus
[G
"], which indicates the energy of deformation used by the sample during and
after a shear
or stressing process, a gel solution was prepared as described in example 1,
the results are
shown in Figure 13 (Graphs of the Viscous Module versus the time for the
formulation of
Example 1), it is observed how the energy of the sample is exhausted by the
change of its
structure until the time of 648 hours
Example 11. The damping factor relates the viscous behavior [G "] and the
elastic
behavior [G '] is defined as the tan 5 = G"/ G', if the quotient of the
modules is < 1 the
character the material is considered a gel, if the quotient of the modules >1
the character
the material is liquid and if the quotient of the modulus is = 0 this is at
its gel point. For the
determination of the Damping factor a solution described in example 1 is
prepared, the
results obtained are show in figure 14 (plot of the Damping factor versus the
time of
formulation of example 1), which indicates that it is a material with GEL
character since the
ratio of the elastic modulus is greater in relation to the viscous modulus.
Example 12. To determine the flow curve, a gellant solution was prepared as
described
in Example 2, the results obtained are shown in Figure 15 (Flow curves at
different
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Date Recue/Date Received 2021-04-12
residence times of the formulation described in Example 2 ), when observing
the graph of
the shear stress with respect to the shear rate, we have a fluid with
pseudoplastic behavior.
Example 13. For the determination of the viscosity curve a solution was
prepared as
described in example 2, the results obtained are shown in Figure 16 (viscosity
curves at
different residence times of the formulation of example 2), observing the
different viscosity
curves dependent on the shear stress at different dwell times of the GEL
sample, this
presents a pseudoplastic behavior, indicating that when the material is
subjected to a
shearing stress, its viscosity decreases.
Example 14. For the determination of the elastic modulus a solution described
in
Example 2 was prepared, the results obtained are shown in Figure 17 (Graph of
the Elastic
Module versus time for the formulation of Example 2).
Example 15. For the determination of the viscous module, a solution described
in
Example 2 was prepared, the results obtained are shown in Figure 18 (Graph of
the Viscose
Module versus time for the formulation of Example 2).
Example 16. For the determination of the Damping Factor a solution described
in
Example 2 was prepared, the results obtained are shown in Figure 19 (Graph of
the
Damping Factor versus time of the formulation of Example 2), which indicates
that it is a
material with GEL character since the ratio of the elastic modulus is greater
in relation to
the viscous modulus. However, a maximum increase in the Damping factor is
observed at
the time of 672 hours which indicates a degradation of the material as it
behaves more and
more like a liquid than an elastic material.
Example 17. According to the table of resistance to the inversion movement in
a glass
tube, developed by Robert Sydanks in 1988, Table 1, the change in the
resistance to
movement of the gel in a fraction of time is qualitatively indicated.
In Figure 20, it shows the advance in gel strength of the formulation
described in
Example 1 and Example 2 as a function of time for two waters with different
salinities. The
first water, called Connate water, contains a higher hardness content such as
calcium
carbonate of approximately 7.283 ppm, a low sulphate value, approximately 240
ppm, a
chloride content of 19.343 ppm and a pH of 6.61. While for the water called
Water Sea, the
hardness content reaches only 1,022 ppm, a significant content of sulfates
with 3,058 ppm,
a content of chlorides of 18,018 ppm and its pH is 8.1. All these variations
of the content of
cations and anions, provide for the case of the formulations developed in the
example 1
and 2, a slight increase in its code of resistance to movement according to
the methodology
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developed by R. Sydanks in 1988. Therefore, the consistence of gel formulated
with
connate water is bigger than the gel formulated with Water Sea.
References.
(1) Lockhart, T.P., SPE, paper 20998, 1991
(2) Seright, R. S., SPE; paper 80200, 2003
(3) Simjoo, M., SPE; paper 122280, 2009
(4) Moradi-Araghi, A., Doe, P.H., SPE, paper 13033, 1984
(5) Moradi-Araghi, A., Doe, P, SPEREJ 2 (2), 1987
(6) Moradi-Araghi, A., SPE, paper 27826, 1994
(7) Hardy, M.B., Botermans, C.W., Smith, P., SPE, paper 39690, 1998
(8) Hardy, M.B., Botermans, C.W., Hamouda, A., Valda, J., John, W., SPE, paper
50738, 1999
(9) Albonico, P., SPE, paper 28983, 1995
(10) R.D. Sydansk, R.D.; SPE/COE 17329, 1988.
(11) Viscometer FANN model 35ATM.
(12)Rheometer Anton Paar model MCR501' .
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