COMPOSITION OF ORGANIC GEL FORMULATIONS FOR ISOLATION OF HIGH TEMPERATURE AND SALINITY PETROLEUM RESERVOIR ZONES

Abstract

This disclosure relates to an organic gel formulation composition for blocking 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., that is, for the purpose temporarily isolating areas of the reservoirs, that will be treated with chemical and radioactive products to quantify the oil remaining 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. A disclosed composition may include 0.3 to 1% by weight of a copolymer of acrylamide butyl tertiary of sulfonic acid and acrylamide, and 0.12 to 0.4% by weight of phenol and from 0.18 to 0.6% by weight of hexamethylenetetramine.

Claims

1. (canceled)

2. A method of isolating a naturally fractured carbonate reservoir, the method comprising: administering a composition of organic gel formulations into the carbonate reservoir, the composition comprising: 0.3 to 1% by weight of a copolymer of acrylamide butyl tertiary of sulfonic acid and acrylamide; and 0.12 to 0.4% by weight of phenol and from 0.18 to 0.6% by weight of hexamethylenetetramine, wherein the salinity conditions of the carbonate reservoir are up to 31,870.50 ppm of dissolved total solids and temperature up to 120.degree. C., and the composition is configured to be stable under such conditions for a period of time up to 24 hours of placement and up to 672 hours of permanence prior to degradation.

3. The method of claim 2, wherein the composition is configured to be subjected to a shear rate that is in a range from approximately 10 to approximately 6000 (1/s) under a temperature of up to 120.degree. C., and at a pressure of up to 2,000 psi.

4. The method of claim 2, wherein the composition is characterized by flow curves and a viscosity that are obtained at different times in a range from approximately 24 to approximately 672 hrs. of permanence at room temperature conditions and under an imposed shear rate in a range from approximately 0.1 to approximately 1,000 (1/s).

5. The method of claim 2, wherein the composition is characterized by a Damping Factor, an elastic modulus, and a viscous modulus that are obtained as a function of time during a range from approximately 24 hours to approximately 672 hours of permanence, at room temperature conditions and under an imposed shear rate of approximately 0.1 to approximately 1,000 (1/s).

6. The method of claim 2, wherein the composition is configured to have compatibility with congenital water of fractured carbonated reservoirs.

7. The method of claim 2, wherein performance of the method leads to production or improved recovery of hydrocarbons.

8. The method of claim 2, further comprising supplying the composition to the carbonate reservoir through an injector-producer well.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] 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 disclosure, the following, the contents of the accompanying drawings are briefly described:

[0012] FIG. 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).

[0013] FIG. 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).

[0014] FIG. 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.

[0015] FIG. 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.

[0016] FIG. 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.

[0017] FIG. 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.

[0018] FIG. 7 shows a diagram of the viscosity measuring equipment for the determination of the rheological model.

[0019] FIG. 8 illustrates the Rheological model of the gellant formulation described in Example 1 for shear rate ranges from 10 to 70 [1/s].

[0020] FIG. 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].

[0021] FIG. 10 shows flow curves at different residence times of the formulation described in example 1.

[0022] FIG. 11 shows viscosity curves at different residence times of the formulation described in example 1.

[0023] FIG. 12 presents a graph of the elastic modulus versus time of the formulation described in example 1.

[0024] FIG. 13 presents a graph of the viscous modulus versus time of the formulation described in example 1.

[0025] FIG. 14 illustrates a graph of Damping factor versus time of the formulation described in example 1.

[0026] FIG. 15 shows flow curves at different residence times of the formulation described in example 2.

[0027] FIG. 16 shows viscosity curves at different residence times of the formulation described in example 2.

[0028] FIG. 17 presents a graph of the elastic modulus versus time of the formulation described in example 2.

[0029] FIG. 18 presents a graph of the viscous modulus versus time of the formulation described in example 2.

[0030] FIG. 19 illustrates a graph of Damping factor versus time of the formulation described in example 2.

[0031] FIG. 20 illustrates a comparative graph of the investment resistance of the formulations described in Example 1 and Example 2 at different salinities.

DETAILED DESCRIPTION

[0032] This disclosure relates to 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 NaCl, 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 use 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.

[0033] The composition of the disclosure can be used where is compatibility with the congenital water of the carbonated naturally fracture reservoir, in addition, it also woks properly where a production assurance or improved oil recovery process is carried out and can be supplied through an injector producer well (FIG. 20).

[0034] For the development processing of the disclosure the following procedure was followed: 1) evaluation of the stability of the gelling formulation at temperature conditions 120° C.; 2) 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 and temperature 120° C.; and 3). Monitoring the progress of cross linking and permanence of the gelling formulation at 30° C. and atmospheric pressure, using rheological tests.

Examples

[0035] 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 disclosure, it being understood that said examples are illustrative only and are not intended to limit the scope of the disclosure.

1) Evaluation of the stability gellant formulation at 120° C. The evaluation of the stability gelling formulation consisted in evaluating different chemical products based on polyacrylamides in an air convention 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.

[0036] 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 FIG. 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.

[0037] 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.

[0038] In FIG. 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 code 3 to code 8 in 192 hours. The code 8 indicate 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 FIG. 11.

[0039] 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 FIG. 2, the behavior of the code developed by Synanks (1988) of the aforementioned 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.

[0040] According to the table of the investment 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.

[0041] In FIG. 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 FIG. 16.

2) Characterization of the Gel Formulation.

[0042] a) Viscosity measurement (21° C.). The viscosity was determined in the FANN 35A viscometer for the formulation described in example 1 and example 2, which is described in example 3 and example 4.

[0043] 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 FIG. 3, which shows the behavior of the viscosity with respect to the shear rate for the formulation of example 1, in FIG. 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.

[0044] 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 FIG. 5, which shows the behavior of the viscosity with respect to the shear rate for the formulation of example 2, in FIG. 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 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-US-00001 TABLE 1 Description of the resistance to investment movement developed by Robert Sydaks, (X). Code Equivalent Definition Description A 1 No detectable The gel appears to have the same gel formed viscosity (fluidity) as the original polymer solution and no gel is visually detectable. B 2 Highly flowing The gel appears to be only slightly gel more viscous (less fluid) than the initial polymer solution. C 3 Flowing gel Most of the obviously detectable gel flows to the bottle cap upon inversion. D 4 Moderately Only a small portion (about 5 to flowing 12%) of the gel does not readily gel flow to the bottle cap upon inversion usually characterized as a tonguing gel (i.e., after hanging out of jar, gel can be made to flow back into bottle by slowly turning bottle upright). E 5 Barely flowing The gel can barely flow to the bottle gel cap and/or a significant portion (>15%) of the gel does not flow upon inversion. F 6 Highly The gel does not flow to the bottle deformable not cap upon inversion. flowing gel G 7 Moderately The gel flows about half way down deformable not the bottle upon inversion. flowing gel H 8 Slightly The gel surface only slightly deforms deformable not upon inversion. flowing gel. I 9 Rigid gel There is no gel-surface deformation upon inversion J 10 Ringing rigid A tuning-fork-like mechanical gel vibration can be felt after tapping the bottle.

[0045] 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 FIG. 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.

[0046] 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 use 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.

[0047] Example 5. Determination of the rheological model of the gallant formulation described in example 1. The shear rate intervals at which the experimental viscosity measurements were made from 10 to 70 (1/s), 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 FIG. 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 FIG. 9, the η and K parameters of the power law model are observed, adjusting the experimental values.

[0048] 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 FIG. 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 FIG. 9, the η and K parameters of the power law model are observed, adjusting the experimental values.

TABLE-US-00002 TABLE 2 Differential experimental pressure at shear rate from 10 to 70 (1/s) for determination of the rheological model Differential Rate Pressure Shear rate Shear stress Viscosity Q[cm.sup.3/h] ΔP [bar] γ[1/s] τ[Pa] η [cP] 10 0.5372 10.0665 1.0164 100.9718 20 1.3205 20.0293 2.6019 124.7289 30 1.8534 30.0439 3.5065 116.7137 40 1.5337 40.0586 2.9017 72.4364 50 1.5821 50.0214 2.9932 59.8376 60 1.9899 59.9841 3.7648 62.7629 70 1.8229 70.0506 3.4489 49.2340

3) Monitoring of the Crosslinking and Permanence of the Gelling Formulation at 30° C. and Atmospheric Pressure, by Rheological Tests.

[0049] The analysis of the flow curve, viscosity curve, Damping Factor, elastic modulus and viscous modulus in Anton Paar 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.

[0050] Example 7. To determine the flow curve, a gel solution was prepared as described in Example 1, the results obtained are shown in FIG. 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.

[0051] Example 8. To determine the viscosity curve, a gel solution was prepared as described in Example 1, the results obtained are shown in FIG. 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-US-00003 TABLE 3 Differential experimental pressure at shear rate from 600 to 1000 (1/s) for determination of the rheological model. Differential Rate Pressure Shear rate Shear stress Viscosity Q[cm.sup.3/h] ΔP [bar] γ[1/s] τ[Pa] η [cP] 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

[0052] 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 FIG. 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.

[0053] 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 FIG. 13 (Graphs of the Viscoso Modulus 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

[0054] Example 11. The damping factor relates the viscous behavior [G″] and the elastic behavior [G′] is defined as the tan δ=G″/G′, if the quotient of the modulus is <1 the character the material is considered a gel, if the quotient of the modulus >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 FIG. 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.

[0055] Example 12. To determine the flow curve, a gellant solution was prepared as described in Example 2, the results obtained are shown in FIG. 15 (Flow curves at different 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.

[0056] Example 13. For the determination of the viscosity curve a solution was prepared as described in example 2, the results obtained are shown in FIG. 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.

[0057] Example 14. For the determination of the elastic modulus a solution described in Example 2 was prepared, the results obtained are shown in FIG. 17 (Graph of the Elastic Modulus versus time for the formulation of Example 2).

[0058] Example 15. For the determination of the viscous modulus, a solution described in Example 2 was prepared, the results obtained are shown in FIG. 18 (Graph of the Viscose Modulus versus time for the formulation of Example 2).

[0059] Example 16. For the determination of the Damping Factor a solution described in Example 2 was prepared, the results obtained are shown in FIG. 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.

[0060] 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 FIG. 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 congenital 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 developed by R. Sydanks in 1988 for when they are formulated in the water called Water Sea, which with water called congenital water.

REFERENCES

[0061] (1) Lockhart, T. P., SPE, paper 20998, 1991. [0062] (2) Seright, R. S., SPE; paper 80200, 2003. [0063] (3) Simjoo, M., SPE; paper 122280, 2009. [0064] (4) Moradi-Araghi, A., Doe, P. H., SPE, paper 13033, 1984. [0065] (5) Moradi-Araghi, A., Doe, P, SPEREJ 2 (2), 1987. [0066] (6) Moradi-Araghi, A., SPE, paper 27826, 1994. [0067] (7) Hardy, M. B., Botermans, C. W., Hamouda, A., Valda, J., John, W., SPE, paper 50738, 1999. [0068] (8) Albonico, P., SPE, paper 28983, 1995. [0069] (9) R. D. Sydansk, R. D.; SPE/COE 17329, 1988.