NANO-INHIBITORS

Abstract

Novel hybrid nanoparticles, useful for inhibiting or slowing down the formation of sulfur deposits or minerals in a well during the extraction of gas or oil. Specifically, the nanoparticles each include (i) a polyorganosiloxane (POS) matrix; and, optionally as a coating over a lanthanide oxide core, (iii) at least one polymeric scale inhibitor during the extraction of gas or oil. The invention also relates to the method for obtaining the nanoinhibitors and the application of same.

Claims

1. Nanoparticles wherein they each include (i) a polyorganosiloxane (POS) matrix; (ii) at least one polymeric deposit inhibitor during the extraction of gas or oil.

2. Nanoparticles according to claim 1, wherein the mass of the deposit inhibitors represents more than 80% of the total mass of each nanoparticle.

3. Nanoparticles according to claim 1, wherein they include a polymeric deposit inhibitor of a molar mass of at least 10 kDa.

4. Nanoparticles according to claim 1, wherein the polyorganosiloxane matrix comprises at least 10% (mol/mol) of free amine groups per silica atom.

5. Nanoparticles according to claim 1, wherein they include a polymeric deposit inhibitor with a negative charge chosen from polymers or copolymers containing at least one of the following functions: carboxylic polyacids, sulphonic acid polymers, phosphates or phosphonates, polyphosphinocarboxylic acids, amide functions.

6. Nanoparticles according to claim 1, wherein they include a polymeric deposit inhibitor chosen from copolymers of styrene sulphonic acid and (poly)carboxylic acid and copolymers of styrene sulphonic and (poly) amido-amine.

7. Nanoparticles according to claim 1, wherein they include furthermore phosphonates.

8. Nanoparticles according to claim 1, wherein they have a mean diameter less than 1 μm.

9. Nanoparticles according to claim 1, wherein the polyorganosiloxane matrix is functionalised by —R groups.

10. Nanoparticles according to claim 1 wherein they do not include a lanthanide oxide core.

11. Nanoparticles according to claim 1 wherein the deposit inhibitors are connected to the polyorganosiloxane matrix by non-covalent electrostatic connections.

12. Method for obtaining nanoparticles according to claim 1 comprises the following steps: a. optionally synthesising a core with a lanthanide oxide base, b. coating the cores of the step (a) with polyorganosiloxane (POS) or preparing a nanoparticle polyorganosiloxane, consisting primarily in implementing a sol/gel technique of hydrolysis-condensation of silicic and alkoxysilane species, in the presence of a base or an acid; c. overcoating the nanoparticles obtained in step (b) consisting primarily in bringing these coated cores or polyorganosiloxane nanoparticles of the step (b) in contact with a solution of polymeric deposit inhibitors in the presence of a non-aqueous solvent, d. optionally purification of the nanoparticles; e. optionally dissolving the cores of lanthanides oxides of the nanoparticles of the step (b) or overcoated nanoparticles of the step (c) consisting primarily in putting them in the presence of a pH modifying agent and/or of a chelator able to complex all or a portion of the lanthanide cations, in such a way that the diameter of the nanoparticles without the overcoating is reduced to a value between 1 and 20 nm; the steps (c), (d), and (e) are able to be carried out in a different order or at the same time.

13. Suspension of nanoparticles according to claim 1 and/or obtained by the method for obtaining nanoparticles comprising the following steps: a. optionally synthesising a core with a lanthanide oxide base, b. coating the cores of the step (a) with polyorganosiloxane (POS) or preparing a nanoparticle polyorganosiloxane, consisting primarily in implementing a sol/gel technique of hydrolysis-condensation of silicic and alkoxysilane species, in the presence of a base or an acid; c. overcoating the nanoparticles obtained in step (b) consisting primarily in bringing these coated cores or polyorganosiloxane nanoparticles of the step (b) in contact with a solution of polymeric deposit inhibitors in the presence of a non-aqueous solvent, d. optionally purification of the nanoparticles; e. optionally dissolving the cores of lanthanides oxides of the nanoparticles of the step (b) or overcoated nanoparticles of the step (c) consisting primarily in putting them in the presence of a pH modifying agent and/or of a chelator able to complex all or a portion of the lanthanide cations, in such a way that the diameter of the nanoparticles without the overcoating is reduced to a value between 1 and 20 nm; the steps (c), (d), and (e) are able to be carried out in a different order or at the same time.

14. Injection liquid for inhibiting or slowing down the formation of deposits during the exploitation of gas or oil, it comprises nanoparticles according to claim 1 and/or, nanoparticles obtained by the method for obtaining nanoparticles comprising the following steps: a. optionally synthesising a core with a lanthanide oxide base, b. coating the cores of the step (a) with polyorganosiloxane (POS) or preparing a nanoparticle polyorganosiloxane, consisting primarily in implementing a sol/gel technique of hydrolysis-condensation of silicic and alkoxysilane species, in the presence of a base or an acid; c. overcoating the nanoparticles obtained in step (b) consisting primarily in bringing these coated cores or polyorganosiloxane nanoparticles of the step (b) in contact with a solution of polymeric deposit inhibitors in the presence of a non-aqueous solvent, d. optionally purification of the nanoparticles; e. optionally dissolving the cores of lanthanides oxides of the nanoparticles of the step (b) or overcoated nanoparticles of the step (c) consisting primarily in putting them in the presence of a pH modifying agent and/or of a chelator able to complex all or a portion of the lanthanide cations, in such a way that the diameter of the nanoparticles without the overcoating is reduced to a value between 1 and 20 nm; the steps (c), (d), and (e) are able to be carried out in a different order or at the same time; and/or the suspension of nanoparticles.

15. Method for obtaining nanoparticles according to claim 1 comprising the following steps: a. optionally synthesising a core with a lanthanide oxide base, b. coating the cores of the step (a) with polyorganosiloxane (POS) or preparing a nanoparticle polyorganosiloxane, consisting primarily in implementing a sol/gel technique of hydrolysis-condensation of silicic and alkoxysilane species, in the presence of a base or an acid; c. overcoating the nanoparticles obtained in step (b) consisting primarily in bringing these coated cores or polyorganosiloxane nanoparticles of the step (b) in contact with a solution of polymeric deposit inhibitors in the presence of a non-aqueous solvent, d. optionally purification of the nanoparticles; e. optionally dissolving the cores of lanthanides oxides of the nanoparticles of the step (b) or overcoated nanoparticles of the step (c) consisting primarily in putting them in the presence of a pH modifying agent and/or of a chelator able to complex all or a portion of the lanthanide cations, in such a way that the diameter of the nanoparticles without the overcoating is reduced to a value between 1 and 20 nm; the steps (c), (d), and (e) are able to be carried out in a different order or at the same time; and/or a suspension of nanoparticles, in order to inhibit or slow down the formation of sulphur and/or mineral deposits during the extraction of gas of oil.

16. The method according to claim 15, in order to inhibit or slow down the formation of sulphur and/or mineral deposits during the extraction in an oil or gas well operating at more than 10 MPa.

17. The method according to claim 15, in the form of an injection of the nanoparticles in squeeze.

Description

LEGENDS OF THE FIGURES

[0079] FIG. 1 is a diagram showing the Blocking test device.

[0080] FIG. 2 is a graph showing static adsorption on a sand sample as a function of the initial concentration of inhibitor.

[0081] FIG. 3 is a graph showing (A) the intensity of phosphorescence and (B) the concentration, obtained with the single polymeric inhibitor (square) or in the form of nanoinhibitors (circles) according to the volume injected.

[0082] FIG. 4 is a graph showing normalized phosphorescence intensity with an inhibitor formulation comprising nanoparticles without gadolinium (top curve) and without nanoparticles (bottom curve) at the outlet of the simple permeation device.

[0083] FIG. 5 is a diagram showing the principle of the permeation tests.

[0084] FIG. 6 is a graph showing the amount of inhibitor measured at the outlet of the permeation device according to the volume injected.

[0085] FIG. 7 is a graph showing analysis by DLS of the size of the silica nanoparticles without gadolinium.

EXAMPLES

Example 1: Preparation of Small Gadolinium Oxide Cores Coated with a Layer of Polysiloxane (or PC4Si)

[0086] A colloid of Gd.sub.2O.sub.3 is prepared in a 10 L temperature controlled reactor and equipped with a mechanical stirrer by dissolving 167.3 g of gadolinium chloride hexahydrate in 3 L of diethylene glycol. The mixture is then heated to 140° C. and stirred at about 300 rpm for 2 to 3 hours, until complete dissolution of the crystals.

[0087] Once all gadolinium chloride crystals are dissolved, is added dropwise 44.55 mL of 10 M NaOH solution. The mixture is stirred at about 250 rpm at 180° C. for 5 hours. The same mixture is then allowed to cool to room temperature (20 to 30° C.) under stirring at 200 rpm for at least 12 hours.

[0088] Measuring the average size of the cores is carried out by laser granulometry directly in DEG without dilution. The mean diameter in volume is 1.5±0.5 nm with less than 5% of particles beyond 5 nm.

[0089] Around these particles, a layer of functionalized polysiloxane is synthesized by sol-gel. To do this, two solutions S.sub.1 and S.sub.2 are prepared as follows:

[0090] For the solution S.sub.1, a homogenized mixture of APTES and TEOS is prepared under an inert atmosphere as follows: in a 2 L bottle, mix 1.6 L of DEG, 51.42 mL of TEOS and 80.61 mL APTES measured using graduated cylinders with a suitable volume.

[0091] As for the solution S.sub.2, mix 190 ml of DEG; 43.1 mL ultra-pure water and 6.94 mL of triethylamine (TEA) in a 250-mL bottle. The volume of DEG is measured with a graduated cylinder of suitable volume and the volumes of TEA and ultra-pure water are removed using an Eppendorf pipette of suitable volume. Homogenize the solution.

[0092] The colloid is then heated to 40° C. under stirring at 250 rpm. A 40° C., all of the solution S.sub.1 is added which is (1732 mL), and this using a peristaltic pump over a duration of 96 h. This corresponds to a flow rate of 300 μL/min. One hour after the start of the adding of the solution S.sub.1 184.3 mL of S.sub.2 is added using a peristaltic pump over a duration of 96 h. This corresponds to a flow rate of 32 μL/min.

[0093] Once the two solutions have been added, the global solution formed is kept under stirring at about 150 rpm at 40° C. for 72 h.

[0094] The solution is brought to ambient temperature (10 to 30° C.) and allowed to sit for at least 12 h.

[0095] At the end of these operations, the measurement of the average size of the particles is carried out via laser granulometry directly in the DEG, without dilution. The mean diameter in volume is 3.0±1.0 nm with less than 5% of the particles beyond 8 nm.

Example 2: Preparation of an Inhibiting Solution of Sodium Salt of Poly (Acid 4-styreenesulphonic-co-maleic Acid) (or Fl1)

[0096] The polymer Fl1, purchased from Sigma Aldrich, (CAS: 68037-40-1; [CH2CH(C6H4SO3R)].sub.x[CH(CO2R)CH(CO2R)].sub.y, R=H or Na), has a molecular weight of about 20 kDa. The polymer has a ratio of three styrene sulphonic acid functions to one maleic acid function.

[0097] One hundred grams of Fl1 are weighed in a 1 L bottle. 1 L of ultra-pure water is then added and a stirring is maintained until total dissolution.

Example 3: Preparation of a Solution of Nano Inhibitors of PC4Si and of Sodium Salt of Poly (Acid 4-styrenesulphonic-co-maleic Acid) (or Fl1-PC4Si)

[0098] In a 100 mL bottle is set to react 50 mL of the solution of Fl1, obtained according to the protocol of example 2, with 2.5 mL of the of PC4Si, obtained according to the example 1, and 47.5 mL of diethylene glycol. The whole is maintained under stirring let for 24 h.

[0099] Measuring the average particle size is then performed by laser granulometry after a dilution of ten times in ultra-pure water. The mean diameter in volume is 55 nm±5.0 nm.

Example 4: Preparation of Solutions of Nano Inhibitors of PC4Si and of Sodium Salt of Poly (Acid 4-styrenesulphonic-co-maleic Acid) (or Fl1-PC4Si) at Different Concentrations in PC4Si

[0100] In six 100 mL bottles are set to react 50 mL of the solution of Fl1, obtained according to the example 2, with respectively, 0 mL, 0.1 mL, 0.5 mL, 1 mL, 5 mL and 10 mL of the solution of PC4Si obtained according to the example 1 and respectively, 50 mL, 49.9 ml, 49.5 mL, 49 mL, 45 mL and 40 mL of diethylene glycol and let to stir 24 h.

[0101] Measuring the average particle size is then performed by laser granulometry after dilution by a factor of ten in ultra-pure water. The mean diameters in volume are respectively 60 nm±10 nm, 65 nm±10 nm, 65 nm±10 nm, 15 nm±1 nm, 10 nm±1 nm and 1 nm±0.05 nm.

Example 5: Preparation of an Inhibiting Solution of Polymer of Acid 1,3-benzenedicarboxylic with 2,2-dimethyl-1,3-propanediol, 2,5-furandione, Hexanedioic Acid, 1,3-isobenzofurandione, 2,2′-oxybis(ethanol) and 1,2-propanediol (IDOS 150 or BelasolS50)

[0102] The polymer, called IDOS150 or BelasolS50, is supplied by R.E.P. Recherche Exploitation Produits (CAS: 110152-61-9).

[0103] 100 grams of IDOS150 are weighed in a 1 L volumetric flask. The volume is then adjusted to 1 L with ultra-pure water and the solution homogenised.

Example 6: Preparation of Inhibiting Solutions of IDOS150-PC4Si at Different Concentrations in PC4Si

[0104] In four 100 mL bottles are set to react 40 mL of ultra-pure water, 5 mL of the solution IDOS150, obtained according to the example 5, with respectively, 0 mL, 0.05 mL, 0.1 mL and 0.25 mL of the solution of PC4Si according to the example 1, and respectively, 5 mL, 4.95 mL, 4.9 mL and 4.75 mL of diethylene glycol. The solutions are then placed under stirring for 24 h.

[0105] Measuring the average particle size is then performed by laser granulometry after dilution by a factor of ten in ultra-pure water. The mean diameters in volume are respectively 450 nm±10 nm, 350 nm±10 nm, 400 nm±10 nm and 300 nm 10 nm.

Example 7: Preparation of an Inhibiting Solution of Terpolymer of Allyl Sodium Sulphonate, of Maleic Anhydride and of 1-Hydroxyethane 1,1-diphophosphonic Acid (TP8106G)

[0106] The polymer, called TP8106G, is supplied by Clariant.

[0107] 50 grams of TP8106G are weighed in a 1 L volumetric flask. The volume is then adjusted to 1 L with ultra-pure water. The solution is homogenised.

Example 8: Preparation of a Solution of Nano Inhibitors of TP8106G-PC4Si

[0108] In a 100 mL bottle are set to react 50 mL of the solution of TP8106G, obtained according to the example 7, with 0.5 mL of the solution of PC4Si, according to the example 1, and 49.5 mL of diethylene glycol and let under stirring for 24 h.

[0109] Measurement of average particle size is performed by laser granulometry after dilution by a factor of ten in ultra-pure water. The mean diameter in volume is 30 nm±5.0 nm.

Example 9: Evaluation of the Inhibiting Effect of Zns by the Tube Blocking Test of the Formulations FL1 and FL1-PC4S

[0110] Evaluation with the Polymer FL1 Alone

[0111] Two saline solutions containing respectively metal cations (A1) and the element sulphur (B1) are mixed in equal proportions (see table 1 for the chemical composition of the solutions). The mixture then passes into a tube in which a deposit of metal salts is likely to be formed). The tube is provided with a filter whereon the deposit is installed with priority which makes the circulation of the fluid difficult. The formation of a deposit is as such accompanied by an increase in the differential pressure between the ends of the tube. The inhibitor is introduced via the solution A1 to which it is added in variable concentrations. A later analysis of the filter by the techniques of SEM and EDX makes it possible to obtain precise information on the quantity and the nature of the deposits formed.

[0112] The device used is shown in the annexed FIG. 1.

TABLE-US-00001 TABLE 1 Composition of the solutions used for the Tube Blocking Test Solution A1 Solution B1 ion (mg/L) (mg/L) Na 63310 117576 Ca 37318 0 Mg 511 0 K 0 0 Ba 0 0 Sr 0 0 SO.sub.4 0 0 Fe 0 0 Pb 0 0 Zn 300 0 S 0 10

[0113] The inhibitor FL1 is added to the solution A1 in variable quantities in such a way as to obtain the concentrations of the table 2 within the tube. As mentioned hereinabove these solutions are co-injected with the solution B1 (proportions 50/50 in volume) via a tube made of a specific alloy (Ni72Cr16Fr8) with an outer diameter of 1 mm and an inner diameter of 0.8 mm. Once they are intimately mixed, the two solutions pass through a filter with a porosity of 7 μm. The solutions are injected with a flow rate of 10 ml/min for both of them. A measurement of the pressure differential that exists on either side of the filter is taken over a duration of one hour. The tests are carried out at a temperature of 125° C. and under a pressure of 45 bars. The results obtained are presented in the Table 2 hereinbelow.

TABLE-US-00002 TABLE 2 Results of the Tubes blocking tests effective concentration increase in in the tube pressure over one (mg/L) hour (psi) deposits observed bare filter N/A none FL1  0 3.3 large quantity of ZnS  5 1.2 low quantity of ZnS 10 1 traces ZnS 30 0 traces of ZnS
Evaluation with the Polymer FL1-PC4Si

[0114] Two saline solutions containing respectively metal cations (A2) and the element sulphur (B2) are mixed in equal proportions (see table 3 for the chemical composition of the solutions). The mixture then passes into a tube in which a deposit of metal salts is likely to be formed). The tube is provided with a filter whereon the deposit is installed with priority which makes the circulation of the fluid difficult. The formation of a deposit is as such accompanied by an increase in the differential pressure between the ends of the tube. The inhibitor is introduced via the solution A2 to which it is added in variable concentrations. A later analysis of the filter by the techniques of SEM and EDX makes it possible to obtain precise information on the quantity and the nature of the deposits formed.

TABLE-US-00003 TABLE 3 Composition of the solutions used for the Tube Blocking Test Solution A2 Solution B2 ion (mg/L) (mg/L) Na 29,505 29,500 Ca 7,223 0 Mg 511 0 K 0 0 Ba 0 0 Sr 0 0 SO.sub.4 0 0 Fe 0 0 Pb 0 0 Zn 200 300 S 0 10 HCO.sub.3 0 0 Cl 55.5 45.4

[0115] The inhibitor FL1-PC4Si is added to the solution A2 in variable quantities in such a way as to obtain the concentrations of the table 2 within the tube. As mentioned hereinabove these solutions are co-injected with the solution B2 (proportions 50/50 in volume) via a tube made of a specific alloy (Ni72Cr16Fr8) with an outer diameter of 1 mm and an inner diameter of 0.8 mm. Once they are intimately mixed, the two solutions pass through a filter with a porosity of 7 μm. The solutions are injected with a flow rate of 10 ml/min for both of them. A measurement of the pressure differential that exists on either side of the filter is taken over a duration of one hour. The tests are carried out at a temperature of 125° C. and under a pressure of 45 bars. The results obtained are presented in the Table 4 hereinbelow.

TABLE-US-00004 TABLE 4 Results of the Tubes blocking tests effective concentration increase in in the tube pressure over one (mg/L) hour (psi) deposits observed bare filter N/A none FL1-PC4Si 0 1.6 large quantity of ZnS 3 0.2 low quantity of Zns 5 0.2 low quantity of Zns 10  0.2 traces of ZnS

[0116] The results show an effectiveness which appears to be substantially equal in terms of inhibiting of the two formulations (with and without nanoparticles PC4Si).

Example 10: Evaluation of the Thermal Ageing of the Inhibiting Solutions

[0117] Evaluation with the Polymer FL1 Alone

[0118] A volume close to 70 mL of FL1, wherein diazote has been bubbled beforehand, is placed under a pressure of diazote of 1000 psi. The temperature is then raised until reaching 225° C. Such anaerobic conditions are maintained for 5 days.

[0119] No significant increase in pressure was able to be measured during the 5 days of testing as what would have been expected in the case of a degradation. An increase in the pH of 3 units is observed. The colour of the solution moreover remains unchanged. An analysis by CPV of the product before and after ageing does not show any significant difference (or any disappearance or appearance of peaks).

Evaluation with the Polymer FL1-PC4Si

[0120] A volume close to 70 mL of FL1-PC4Si, wherein diazote has bubbled beforehand, is placed under a pressure of diazote of 1000 psi. The temperature is then raised until reaching 225° C. Such anaerobic conditions are maintained for 5 days.

[0121] No significant increase in pressure was able to be measured during the 5 days of testing as what would have been expected in the case of a degradation. A decrease in the pH of 3 units is however observed as well as a darkening of the solution. An analysis by CPV of the product before and after ageing does not show any significant difference (or any disappearance or appearance of peaks).

Example 11: Evaluation of the Inhibiting Effect by the Tube Blocking Test after Thermal Ageing

[0122] Two saline solutions containing respectively metal cations (A2) and the element sulphur (B2) are mixed in equal proportions (see table 5 for the chemical composition of the solutions). The mixture then passes into a tube in which a deposit of metal salts is likely to be formed). The tube is provided with a filter whereon the deposit is installed with priority which makes the circulation of the fluid difficult. The formation of a deposit is as such accompanied by an increase in the differential pressure between the ends of the tube. The inhibitor is introduced via the solution A2 to which it is added in variable concentrations. A later analysis of the filter by the techniques of SEM and EDX makes it possible to obtain precise information on the quantity and the nature of the deposits formed.

[0123] The device used is shown in the annexed FIG. 1.

TABLE-US-00005 TABLE 5 Composition of the solutions used for the Tube Blocking Test Solution A2 Solution B2 ion (mg/L) (mg/L) Na 29505 29500 Ca 7223 0 Mg 511 0 K 0 0 Ba 0 0 Sr 0 0 SO.sub.4 0 0 Fe 0 0 Pb 0 0 Zn 200 300 S 0 10 HCO.sub.3 0 0 Cl 55.5 45.4

[0124] The inhibitor FL1-PC4Si (which has or has not been subjected to thermal ageing) is added to the solution A2 in variable quantities in such a way as to obtain in the end the concentrations of the table 6. These solutions are then co-injected with the solution B (proportions 50/50 in volume) via a tube made of a specific alloy (Ni72Cr16Fr8) with an outer diameter of 1 mm and an inner diameter of 0.8 mm. Once they are intimately mixed the two solutions pass through a filter with a porosity of 7 μm. The solutions are injected with a flow rate of 10 ml/min for both of them. A measurement of the pressure differential that exists on either side of the filter is taken over a duration of one hour. The tests are carried out at a temperature of 125° C. and under a pressure of 45 bars. The results obtained are presented in the Table 6 hereinbelow.

TABLE-US-00006 TABLE 6 Results of the Tube blocking tests effective concentration increase in in the tube pressure over one (mg/L) hour (psi) deposits observed bare filter N/A none FL1-PC4Si not aged 0 1.6 large quantity of ZnS 3 0.2 low quantity of Zns 5 0.2 low quantity of Zns 10  0.2 traces of ZnS FL1-PC4Si aged 0 1.7 large quantity of ZnS 1 0.8 traces of ZnS 3 0.2 traces of ZnS 5 0.2 traces of ZnS

[0125] This example shows that the thermal ageing did not affect the effectiveness of the deposit inhibitor FL1-PC4Si.

Example 12: Evaluation of the Inhibiting Effect of Carbonate by the Tube Blocking Test of the IDOS150 (Bellassol S50) and IDOS150-PC4Si

[0126] In order to test the inhibiting power of the two formulations a blocking test was set up. It consists in measuring the time required for a blocking of the filter via a deposit of metal salts is produced.

[0127] The results of this test show that at concentrations of 1 ppm and of 5 ppm the two formulations fulfil their roles of an inhibitor. It is observed moreover that the two formulations are close in terms of effectiveness.

Example 13 Evaluation of the Absorption/Desorption of the Inhibitors Belassol S50 (Water Additives) and NanoBellassol S50-PC4Si on a Sample of Sand

[0128] This entails evaluating the capacity of the inhibiting formulations to be adsorbed physically or chemically over the mineral surface of the porous medium modelled by a sample of sand in the case at hand. This adsorption can be a function of several variables (Concentrations, pH, temperature, etc.). The inhibitor is then released via desorption. At equilibrium, the static adsorption Γ (mg/g) is represented by the following equation:

[00001]$\Gamma =\frac{\left(C_0-C_{\mathrm{eq}}\right).Math.V}{m}$

[0129] Where C.sub.0 is the initial concentration of the inhibitor in mg/L. V is the volume of the inhibitor solution in L. C.sub.eq is the concentration of the inhibitor in equilibrium in mg/L and m is the mass of the porous medium.

[0130] A series of adsorption experiments on sand with two inhibitors was carried out. The two formulations tested are that of IDOS 150 (Belassol S50) described in example 5 and that of IDOS150-PC4Si described in example 6. The mean diameter in volume measured by laser granulometry is 210 nm±10 nm. The results obtained are provided in table 7 and FIG. 2.

TABLE-US-00007 TABLE 7 IDOS150-PC4Si IDOS150 C.sub.0 C.sub.0 C.sub.0 (mg/L) (mg/L) IDOS150 IDOS150-PC4Si (mg/L) IDOS150 Si C.sub.eq (mg/L) Γ (mg/g) C.sub.eq (mg/L) Γ (mg/g) 0 0 0 0 0 0 0 250 250 7.5 121.5030565 0.192745415 113.1596752 0.205260487 500 500 15 318.4133682 0.272379948 279.7862917 0.330320563 12500 12500 150 205.6291528 18.44155627 1837.862013 15.99320698 25000 25000 300 3470.889381 32.29366593 830.2890173 36.25456647

[0131] The results indicate that the Nanoinhibitor IDOS 150-PC4Si is adsorbed and is desorbed on the sand in the same way as the inhibitor IDOS150 alone.

Example 14: Test of Simple Permeation

[0132] In order to test the affinity of the inhibitors with the rock, a so-called “simple permeation” test was developed. The latter consists in injecting into a cartridge of rock a synthetic solution of sea water containing the inhibitor in question. Once the cartridge is filled with the inhibiting solution, sea water alone is injected and the outlet of the inhibitor is monitored. The diagram of the device is provided in FIG. 5.

[0133] The cartridge in question is comprised of a cylindrical core of rock encased in a PVC tube and linked to the latter by an epoxy resin. The bases are perforated on either side of the cartridge allowing a dual syringe pump system to ensure a continuous flow through the system at a variable flow rate.

[0134] The presence of the inhibitor at the outlet is detected by complexation of free terbium ion by the latter. Once chelated, the phosphorescence of the Terbium ions is substantially exalted.

[0135] The first step consists in carrying out the circulation of sea water alone at a height of about 100 times the porous volume of the core of rock through (300 mL/h). Once washed in this way, the cartridge is ready to receive the inhibitor.

[0136] A first test was conducted using a solution of TP8106G at 1% by weight of inhibitor with or without silica nanoparticles without gadolinium (this is more precisely a solution A/20; see example 16 and 17 for the synthesis of the nanoparticles and the preparation of the formulation of inhibitor with nanoparticles). The inhibiting solutions are injected in diluted form into the sea water (solution at 2% by weight): 5 times the porous volume of this solution has passed through the rock (at a flow rate of 500 mL/h). The injecting of sea water alone is then resumed (300 mL/h) until it is no longer possible to detect the inhibitor in the samples taken automatically at regular intervals of time at the outlet of the core. The results can be seen in FIG. 4. A more substantial retention is observed for the nanoparticulate formulation of the inhibiting solution (squares) as for the conventional formulation (circles).

[0137] The same observation is established for a formulation with PC4Si or without nanoparticles of the inhibitor IDOS 150 (FIGS. 3A and 3B).

Example 15: Permeation Test

[0138] In order to test the affinity of the various inhibiting formulations with the rock, a so-called “permeation” test has been developed. The block diagram is provided in FIG. 5. The difference with the simple permeation test in example 14 is a temperature maintained here at 195° C. The permeability of the device is between 400 and 700 mD.

[0139] The results of this test are shown in FIG. 6 and show a more substantial delivery of inhibitors over a long time for the Nanoinhibitor formulation.

Example 16: Synthesis of Silica Cores without Gadolinium

[0140] The synthesis of silica nanoparticles without gadolinium is carried out via simple mixture of precursors of the organosilane type: (3-Aminopropyl)triethoxysilane and tetraethyl ortho silicate (APTES and TEOS) in water. TEOS is added under strong stirring alone then after about 10 minutes APTES is also added with the stirring being maintained. The proportions of the two reagents can be varied. The solution is then kept under stirring for one night. No step of purification is carried out afterwards.

[0141] FIG. 7 provides the signature in dynamic diffusion of the light (DLS) of the nanoparticles at the end of synthesis for proportions 50/50 in mass of APTES and of TEOS. The solution A (squares) is obtained by adding 5 mL of TEOS and 5 mL of APTES to 1 L of pure water. The solution B (circles) by adding 1 mL of TEOS and 1 L of APTES to 1 L of pure water. The mean sizes obtained are respectively 720 nm and 190 nm.

Example 17: Preparation of Solution of Nanoinhibitors TP8106G with Nanoparticles without Gadolinium

[0142] The solutions A and B obtained in example 16 are diluted by a given factor of dilution and left under stirring for a duration between 1 h and 72 h. The solutions obtained as such are then mixed in equal proportions by a commercial solution of TP8106G which is itself diluted by 2. The solutions finally obtained are left under stirring for 24 h then are analysed via DLS.

[0143] As such the 50/50 mixture in volume of the solution A diluted by 100 and allowed to mature for one hour with the solution of TP8106G diluted by 2 gives a mean size of 249 nm after 24 h of mixing.

[0144] The 50/50 mixture in volume of the solution B diluted by 10 and left to mature for one hour with the solution of TP8106G diluted by 2 gives a mean size of 491 nm after 24 h of mixing.