FR2680827A1 - Use of new compositions based on gels for the reduction of the production of water in oil or gas production wells - Google Patents

Abstract

Use of new gel compositions usable for reducing water production in wells producing oil or gas. The gel compositions include a solution of at least one water-soluble complex of a polyvalent metal cation such as zirconium lactate, capable of crosslinking a nonionic polysaccharide such as scleroglucan, in a concentration of 2 to 100 parts per million parts, expressed as weight of metal dioxide. The compositions make it possible to form aqueous scleroglucan gels which can be employed for preventing entries of water into hydrocarbon production wells.

Description

 The present invention relates to the use of novel crosslinking compositions for polysaccharides, in particular scleroglucan. It also relates to the use of aqueous gels including these crosslinking compositions for the selective reduction of water production in oil or gas producing wells. They have a particularly great interest when the permeability of the treated formation in the vicinity of the well is high and / or when the produced water is hot and / or salty, for example at a formation temperature of 70 to 1300C and / or salinity water produced at least equal to that of seawater (at least 30 g / l, expressed in Nazi). These new compositions are particularly applicable to enhanced oil recovery.

 The recovery of liquid or gaseous hydrocarbons from underground formations is very frequently accompanied by the production of large quantities of water. In some cases, although significant hydrocarbon production is obtained, water production is so important and water treatment costs so high that hydrocarbon production is not economical. In heterogeneous reservoirs, the excessive production of water is often caused by the digitation of the water injected by the areas of high permeability. This leads to a premature water breakthrough at the production well, a poor volumetric sweep and ultimately an inefficient recovery of hydrocarbons.

 Many methods to reduce the water production of highly permeable formations have been proposed and tested in the field; they generally consist in introducing into the formation, at the level of the zone to be isolated, either a cement or a suspension of solid particles or paraffins. Resins or gels of water-soluble polymers have more recently been proposed and implemented. All these processes have the disadvantage of not being selective and blocking almost as much the flow of oil or gas as that of water.

 More recently it has been proposed the use of water-soluble polymers of high molecular weight in the absence of any crosslinking or bridging agent, which have the advantage over previous solutions and in particular those using resins or gels of polymers, to reduce the flow of water without adversely affecting the production of oil or gas.

 Among these water-soluble polymers, nonionic polysaccharides and in particular scleroglucan are particularly effective in selectively reducing the production of water production wells while preserving the production of hydrocarbons. Thus, US Pat. No. 4,718,491 and the patent application FR 89/1716 of the applicant advocate the use of different polysaccharides, and in particular of a scleroglucan, in the absence of any crosslinking or bridging additive, for the selective reduction of permeability in the vicinity of an oil or gas production well.If the preferred field of application of these polymers covers the production of hot water (up to at 1300C) and salt, its effectiveness decreases when the permeability of the formation becomes high and in particular if it is greater than 1 Darcy.

 The French patent application 90/13385 describes a crosslinking composition comprising at least one water-soluble complex based on polyvalent metal cation and organic acid complexing cation capable of crosslinking a polysaccharide, in particular scleroglucan.

 US Pat. No. 4,647,312 also recommends the use of scleroglucan complexes and a polyvalent metal ion such as titanium, zirconium and chromium for the production of very high viscosity fluids and their use. in oil recovery. Although no mention is made in this patent on the ability of these gels to propagate in a subterranean formation the increase in viscosity obtained shows that they are strong gels that should have no selective character and therefore reduce both water production and hydrocarbon production. In addition, it is suggested to use zirconium tetrachloride, but the latter has the disadvantage of being insoluble in a saline water close to that of seawater.

 The object of the present invention overcomes the drawbacks cited and therefore relates to the use of new gel compositions for the selective reduction of water production in oil or gas producing wells.

 More specifically, the invention relates to a method for the selective reduction of the water permeability in an oil and / or gas-producing subterranean formation according to which at least one hydrocarbon-producing well is injected with a composition of aqueous gels in the formation surrounding the producing well at a suitable flow rate and / or pressure and the well is returned to production, characterized in that said aqueous gels composition comprises a solution of at least one nonionic polysaccharide and at least one water-soluble polyvalent metal cation complex and cation-complexing organic acid capable of cross-linking said polysaccharide, said complex being at a concentration, expressed by weight of metal dioxide, of 2 to 100 parts per million of parts of the solution.

 Advantageously, zirconium Zr (IV) or Ti (W) titanium is used. The organic acid advantageously recommended is an alphahydroxy acid.

 Among the alphahydroxy organic acids, an alphahydroxycarboxylic acid such as lactic acid or malic acid will be chosen more particularly.

 Excellent results have been obtained in terms of selectivity when the acid is lactic acid and the zirconium cation.

 Among the polysaccharides satisfying the criteria of the invention, preference will be given to nonionic polysaccharides such as glucans and in particular scleroglucan and schizophyllan, galactomannan gums, for example guar gum and in particular its substitution derivatives, for example hydroxypropylguar and carboxymethylguar and mixtures thereof.

 Of the nonionic polysaccharides of the invention preference will be given to scleroglucan. The latter is a nonionic branched homo-polysaccharide whose main chain consists of successions of 131-3 Dglucose type units, substituted every three units by a ss 1-6 D-glucose unit. Scleroglucan is obtained by fermentation of media containing carbohydrates initiated by Sclerotium fungi and in particular by a Sclerotium Rolfsii type fungus (ATCC 15206).

The zirconium or titanium complexes capable of forming a gel in an aqueous medium with scleroglucan are advantageously zirconium or titanium complexes based on malic or lactic acid, the molar ratio of alphahydroxycarboxylic acid / zirconium or titanium preferably being between 0. , 5 and 4 and more particularly between 2 and 4 with lactic acid and 0.5 and 1.5 with malic acid. As an example, the commercial products sold by SCPI (Société des Produits Chimiques Industriels) under the names of
ZIRCOMPLEX PN or ZIRCOMPLEX PA or by the company ZIRTECH based in Gainesville, Florida under the name of ZIRTECH LA.

 The polymer weight concentrations for obtaining gels according to the invention generally vary between 150 and 5000 ppm and preferably between 200 and 2000 ppm.

 The concentrations by weight of polyvalent metal complex and preferably of titanium or zirconium, expressed by weight of metal oxide, vary between 2 and 100 ppm, advantageously from 3 to 95 ppm and preferably between 5 and 25 ppm. It is even possible to use concentrations of from 100 to 10,000 ppm by weight of metal oxide, advantageously from 120 to 8000 ppm, and preferably from 1000 to 5000 ppm in certain applications relating to highly permeable or cracked reservoirs where the production zones of water and hydrocarbons are very clearly separated.

 By aqueous medium, it is meant water with all the constituents likely to be dissolved, that is to say the salts, but also other additives necessary for application as basic constituents such as sodium hydroxide, or surfactants or bactericides.

 The composition according to the invention, especially in the recommended concentration range (2-100 ppm) can be used to selectively reduce the water permeability in a production well without substantially affecting the hydrocarbon permeability. In fact, after having found in these wells that more water was produced than oil, essentially by the zones of higher permeability, the pumping or the production system of these wells was stopped and injected. composition according to the invention in said wells, especially when the range of metal oxide concentrations corresponds to the formation of a weak gel (2-100 ppm).

 After injection of a volume corresponding to a radial extension of the composition from 1 to 30 meters from these wells, optionally followed by a closing time of a few days to facilitate on the one hand the adsorption of the polymer and of on the other hand, to allow the gelation reaction to go to completion, the wells are returned to production and it is found that while producing less water through the zones of high permeability, the production of hydrocarbons by areas of low permeability is increased. The delivery of the production wells is generally carried out progressively and as much as possible at flow rates and / or pressures equal to or lower than those which had been used for the injection of the aqueous composition.

 A first method of setting up the formulation according to the invention consists in simultaneously mixing all the constituents of the gel at the wellhead and injecting them simultaneously into the formation. The gelling reaction is then done within the formation to be treated. This method is particularly applicable when it is desired to form a weak gel in an area of the formation simultaneously producing water and hydrocarbons.

 A second method of setting up the formulation according to the invention, and corresponding to the use of strong gels in a zone of the essentially water-producing formation, consists in making successive alternating injections first of crosslinking solution. and then polymer. Thus, by successive crosslinking, a polymer adsorbed multilayer by means of the crosslinking agent can go up to the formation of a compact gel with capping of the water-producing zone.

 Preferably, the injection of the nonionic polysaccharide mixture and of the crosslinking complex into the producing well is carried out under a flow rate and / or a pressure sufficient to allow easy introduction into the subterranean formation but at a pressure below the layer limit pressure. or fracturing pressure.

 Sufficient flow rate and / or pressure means a flow rate and / or a pressure corresponding to a shear rate of at least 50 sl. The viscosity of the polysaccharide-crosslinking complex mixture at this gradient is preferably less than 10 mPa.s, for example 1 to 9 mPa.s (1 mPa.s = 1 cP).

 For the implementation of the formulation according to the invention and its injection into a hydrocarbon-producing well will work advantageously at a pH below 9, the pH value nevertheless depending on the temperature of the tank to be treated. For high temperature applications, the formulation will preferably be injected at a pH close to neutrality.

 The following examples are intended to illustrate the various advantages of using the formulations according to the invention. They include test-tube tests for the establishment of soil / gel phase diagrams as well as tests for placement in porous media under conditions as close as possible to those existing in the oil-bearing formation.

Tests in test tubes
Example 1: Tube tests were first performed on raw solutions of scleroglucan powder, ACTIGUM CS 1 1 PVE SANOFI Company
BIOINDUSTRIES, FRANCE, in water containing 50 g / l of NaCl. Different solutions at increasing concentrations of polymer (from 125 ppm to 3000 ppm) were prepared, their viscosity measured using a viscometer LS 30 from the company CONTRAVES for a shear gradient of 10 sl. Increasing concentrations (5 to 100 ppm) ZrOTE 2 of ZIRTECH LA (7% by weight of ZrO 2) manufactured by ZIRTECH, USA were added to each of these polymer solutions.

 The solutions were aged during Ajours in an oven thermostated at 300C, the viscosities again measured. In Table 1 are reproduced in front of each polymer concentration the minimum amounts of zirconium complex required to obtain a viscosity increase of at least 50% of the polymer solution as a result of a gelling reaction at 300C. It should be noted that as a result of the addition of the zirconium complex the pH of the polymer solution progressively increases from 6.5 to 7.3. Moreover no gelling or significant increase in viscosity is observed for polymer concentrations below 150 ppm (recovery concentration).

Table 1
Establishment of the sol / gel diagram for the lactate couple
of zirconium-scleroglucan (after 5 days at 300 C)

<tb> Scleroglucan <SEP> Zr <SEP> 02
<tb><SEP> (ppm) <SEP> (ppm)
<tb><SEP> 125 <SEP> not <SEP> of <SEP> gelation <SEP>
<tb><SEP> 250 <SEP> 15
<tb><SEP> 500 <SEP> 10
<tb><SEP> 1000 <SEP> 15
<tb><SEP> 2000 <SEP> 30
<tb><SEP> 3000 <SEP> 50
<Tb>
Example 2: The tube tests of Example 1 were renewed except that the different samples were aged in an oven thermostated at 800C and the viscosities were measured after 3 days at this temperature.

The results in Table 2 show that the minimum concentrations of zirconium lactate are substantially the same at 800C and 300C but that the kinetics of reaction is substantially above 800C (measurements after 3 days instead of 5 days in Example 1) .

Table 2
Establishment of the sol / gel diagram for the lactate couple
of zirconium-scleroglucan (after 3 days at 800C)

<tb> Sciotoglucan <SEP> zr <SEP> Q <SEP>
<tb><SEP> (ppm) <SEP> (ppm)
<tb><SEP> 125 <SEP> not <SEP> of <SEP> gelation
<tb><SEP> 250 <SEP> 15
<tb><SEP> 500 <SEP> 15
<tb><SEP> 1000 <SEP> 20
<tb><SEP> 2000 <SEP> 30
<tb><SEP> 3000 <SEP> 50
<Tb>
Example 3: The tube tests of the preceding examples were repeated by dispersing this time the hydroxypropyl guar powder, GALACTASOL 476 from AQUALON, France, in water containing 50 g / l of NaCl. A significant increase in viscosity corresponding to gelation of the polymer solution is observed after 3 days at 300C and 1 day at 800C for solutions containing respectively 2000 or 3000 ppm of polymer and ZIRCOMPLEX PA of the Company of Industrial Chemicals (SCPI) titrating 5 ppm in ZrO2.

Note that if in these tests carried out at pH 7 we increase the pH to 9 by addition of a base we obtain an almost instantaneous gelation of the polymer solutions even at room temperature.

Tests in porous media
Examples 4 to 8: In order to test according to the invention the effectiveness of formulations based on weak gels to reduce the water permeability without affecting the permeability to hydrocarbons, the described experimental procedure was applied to various porous media in the communication of A. Zaitoun and N. Kohler to the Society of Petroleum Engineers under reference SPE 18085 of October 1988 and comprising the following steps: 1. Saturation of the porous medium with brine and determination of the
initial permeability to water kwi 2. Injection of oil to irreducible saturation in SWi water.

3. Brine injection to irreducible oil saturation Sor.

4. Repeat steps 2 and 3 until the extreme values of
relative permeabilities krW and kro are reproducible.

5. At the irreducible saturation in oil, injection of the polymer alone (reference) or
polymer + crosslinking agent. Stop the flow of fluids to allow
the gelling reaction to go to completion.

6. Brine injection until all of the unadsorbed polymer is
moved. It is verified that the viscosity of the effluent corresponds to that of the
brine. The RkW water permeability reduction curve is plotted against
flow or shear rate 7.

7. Oil injection to irreducible saturation in Swi water. Determination of
the new high throughput kro value (Welge method).

8. Injection of water to Sor and determination of the new value of krw to strong
debit.

The shear gradient in porous media is calculated as follows:
4v Y r
where v is the superficial velocity calculated by:
v = 4q
S (p (1 - Sor)
where q is the injection flow rate, S the surface of the inlet face of the porous media, (p
porosity
r the average pore radius calculated by:
r = 8k krw
# (l - Sor)
where k is the initial permeability to water of the porous medium.

Rkw brine permeability reduction is a measure of viscosity
apparent brine circulating in the porous medium after introduction of the
polymer or gel.

 The relative permeability measurements krw and kro, carried out at the same saturation state Sw and for the same flow rate q, correspond to the pressure losses due to the circulation of the fluids, water or oil, before and after setting up of the polymer or gel .

Example 4
The first experiment of implementation of the formulation according to the invention was carried out on a Vosges sandstone massif inserted into a Hassler cell, the whole being put in an oven at 950C. Pressure sensors make it possible to measure the pressure drops at the terminals of the core and a volumetric pump makes it possible to inject the fluids with constant flow.

 The initial permeability to water kwj (140 g / l of total salinity) was found to be equal to 1.5 D. The injection of oil (11 = 1.97 cP at 930 C) was followed successively. to its irreducible saturation in water and one measures the permeability relative to the oil (kro = 0.92, Swt = 0.34 and kro = 0.28, Sw = 0.48), then to the injection of water to irreducible saturation in oil and the relative permeability to water (krW = 0.05, Sor = 0.46) is measured.

 A solution of 1.5 g / l of scleroglucan powder, ACTIGUM CS 1I PVE from SANOFI BIOINDUSTRIES, dispersed in salt water at the rate q = 20 cm3 / h, is then applied. The adsorption of the polymer is found to be equal to 120 Clg / g.

 The brine is then injected to displace the unadsorbed polymer, and the water permeability reduction RKW1 is then measured at different water injection rates (Table 3).

 The mass is then saturated with a mixture of scleroglucan (Cp = 1.5 g / l) and zirconium complex, ZIRTECH LA (Czro2 = 30 ppm), a mixture which gives rise to a gelling reaction in tube at the temperature of 950C, and stop any flow of fluid for 16 hours. The excess of the non-adsorbed or unreacted mixture is displaced by water injection and the water permeability reduction is again measured at different RKW2 flow rates (table 3).

Table 3
Vosges sandstone at 95 and 1200C
Water Permeability Reductions After Polymer Only (RKW1)
and after polymer + zirconium lactate (RKW2)

<tb><SEP> Flow <SEP> Gradient <SEP> of <SEP> Rw1 <SEP> RKW2
<tb><SEP> Shear <SEP> Polymer <SEP> Single <SEP> Polymer <SEP>
<tb> q (cm3) h) <SEP> oy <SEP> (sl) <SEP> + <SEP> Complex <SEP> Zr
<tb><SEP> 4 <SEP> 12.4 <SEP> 5.00 <SEP> 64.3
<tb><SEP> 10 <SEP> 31 <SEP> 3.80 <SEP> 42.4
<tb><SEP> 30 <SEP> 93 <SEP> 3.13 <SEP> 24.9
<tb><SEP> 50 <SEP> 155 <SEP> 2.76 <SEP> 12.1
<Tb>
It is found that the water permeability reduction values after injection of the mixture according to the invention are much greater than those measured after injection of polymer alone.

In addition it is possible to show using the Welge method that the permeability relative to the oil (kro = 0.24, Sw = 0.48) is not affected by the presence of the weak gel whereas the relative permeability with water (krW = 0.011,
Sw = 0.54) is greatly reduced with respect to the initial permeability (krw = 0.03 at the same saturation value in water).

 The formulation according to the invention therefore greatly reduces the permeability to water without substantially affecting the permeability to the oil. The system remains selective.

 The temperature of the oven was then raised to 1200C in order to test the stability of the formulation at this temperature in a porous medium. Synthetic seawater, carefully deoxygenated by the addition of 100 ppm sodium sulphite, was continuously injected under a nitrogen atmosphere at a rate of 1 mUh into the porous medium and the pressures measured daily for 14 days at 1200C.

It can be seen that the permeability reduction value measured at this flow rate (Rk = 103) proved to be particularly stable during this experiment (final value Rk = 95).

 The formulation according to the invention therefore makes it possible to reduce the permeability to water even at this temperature for quite prolonged periods.

Example 5
The previous experience is renewed using this time a sandstone ENTRAIGUES EN 38 reconstituted in a stainless steel cell
Hastelloy, all placed in an oven at 800C.

 The permeability relative to the water (reconstituted seawater) of the massif is found to be equal to 2.32 D. It is successively proceeded with Injection of oil (, u = 2.43 cP at 800 C) until saturation irreducible in water and the permeability relative to the oil is measured as before for 2 water saturation values (kro = 0.615, Sw = 0.30 and kro = 0.22, Sw = 0.43). As a result of the water injection, the initial water permeability values (k = 0.30, Sw = 0.79) are determined.

 The injection of a solution of scleroglucan (Cp = 1.5 g / l) in seawater gives rise to an irreversible adsorption of the latter equal to 80 Rg / g.

 Following the injection of water and the total displacement of the unadsorbed polymer, the permeability reduction values RKW1 of Table 4 are observed.

Table 4
Sand of Entries at 80 C:
Water Permeability Reductions After Polymer Only (RKW1)
and after polymer + zirconium lactate (RKW2)

<tb><SEP> Flow <SEP> Gradient <SEP> of <SEP> Rv1 <SEP> I <SEP><SEP> RKW2 <SEP>
<tb><SEP> shear <SEP> polymer <SEP> only <SEP> polymer
<tb> q (cm3) h) <SEP> r <SEP> (sl) <SEP> + <SEP> Complex <SEP> Zr
<tb><SEP> 10 <SEP> 10.2 <SEP> 4.39 <SEP> 179.8
<tb><SEP> 20 <SEP> 20.4 <SEP> 2.74 <SEP> 118.0
<tb><SEP> 30 <SEP> 30.6 <SEP> 2.30 <SEP> 95.8
<tb><SEP> 50 <SEP> 51 <SEP> 1.97 <SEP> 74.1
<tb><SEP> 100 <SEP> 102 <SEP> 1.75 <SEP> 57.7
<tb><SEP> 200 <SEP> 204 <SEP> 1.48 <SEP> 45.0
<Tb>
An injection is then made of a formulation according to the invention containing
1.5 g / l of scleroglucan powder and 25 ppm of zirconium complex
ZIRCOMPLEX PA SCPI titrating 7.3% by weight of ZrO2, formulation capable of forming a weak gel at 800C, and stopped fluid flow for 16 hours.

 The procedure is then followed, as previously, with the injection of water and the measurement of the reduction in water permeability at different RKW2 flow rates (Table 4). The values obtained here are also much greater than those resulting from the adsorption of the polymer alone.

 The selectivity of the system is proven by comparing oil and water permeabilities before and after placing the weak gel (Welge method). The permeability relative to the water klw thus goes from an initial value equal to 0.30 to a final value equal to 0.012 for the same state of saturation Sw = 0.79. The permeability relative to the oil kro passes from an initial value equal to 0.22, Sw = 0.43 to a final value very close to 0.17 at the same state of saturation.

 The selectivity of the formulation according to the invention is thus again demonstrated.

Example 6
Previous experiments are repeated using this time a porous medium consisting of St Waast les Mello limestone inserted in a Hassler cell and put in an oven at 800C.

 The initial permeability to seawater is found to be 931 mD. The porous medium is put into residual oil (ass = 2.40 cP) and the permeability to seawater in the presence of residual oil kSOR is found to be 157 mD.

 The procedure is as before for injecting a solution of scleroglucan powder (Cp = 1500 ppm) serving as a reference and then for injecting a mixture of polymer (Cp = 1500 ppm) and ZIRTECH LA (CZrO2 = 24 ppm). ).

After stopping for 19 hours at 800 ° C., the water permeability reduction values are measured.

 Table 5 summarizes the water permeability reduction results after respective establishment of the polymer alone and the formulation according to the invention.

 An aging test was also performed by injecting low-flow seawater for 13 days at 800C and making a daily measurement of the reduction in permeability to water. Table 5 shows that the values obtained are perfectly stable over time (RKW3).

 In the same way as previously it is demonstrated that the weak gel is selective in a carbonated medium, strongly reducing the permeability to water without substantially altering the permeability to the oil.

Table 5
Limestone of St Waast les Mello at 800C
Water Permeability Reductions After Polymer Only (RKWl)
and after polymer + zirconium complex before (RKW2) and
after (RKW3) aging.

<Tb>

<SEP> Flow <SEP> Gradient <SEP> of <SEP> Rv1 <SEP> RKW2 <SEP> I <SEP> RKW3
<tb><SEP> shear <SEP> polymer <SEP> alone
<tb> q <SEP> (cm3 / h) <SEP> Y <SEP> (sl) <SEP> polymer <SEP> + <SEP> complex <SEP> Zr
<tb><SEP> 2 <SEP> 4.9 <SEP> 11.80 <SE> 64.6 <SEP> 103.50
<tb><SEP> 10 <SEP> 24.5 <SEP> 4.48 <SEP> 23.54 <SEP> 24.95
<tb><SEP> 20 <SEP> 49 <SEP> 3.98 <SE> 16.66 <SE> 16.67
<tb><SEP> 50 <SEP> 122.5 <SEP> 3.30 <SEP> 11.52 <SEP> 12.53
<tb><SEP> 100 <SEP> 245 <SEP> 3.01 <SEP> 9.50 <SEP> 10.3
<Tb>
Example 7
In a massive Entraigues sand set in an oven at 500C and whose permeability to synthetic seawater (30 g / l of NaCl and 3 g / l of CaCl2.2H2O) was found to be 4.8 D, we proceeded to the injection of a 2500 ppm solution of hydroxypropylguar, GALACTASOL 476 of the AQUALON Company, in the sea water at the rate of 20 mVh. This polymer injection was followed by seawater injection in order to displace the excess of non-adsorbed polymer and a water permeability reduction of 1.8 was found to be substantially independent of the injection rate. 'water.

In the same mass, the same flow rate of 20 mVh was then applied to the injection of a mixture in synthetic seawater containing 2500 ppm of hydroxypropylguar, 10 ppm of ZIRCOMPLEX PN (9.9% by weight of ZrO2) and 100 ppm of citric acid and after stopping the circulation for 1 night at 500C it was proceeded as before to the injection of synthetic seawater to displace the excess polymer. The reduction in final permeability to seawater was found to be 290 at this same flow rate of 20 mph.

Claims (10)

1. Process for the selective reduction of water permeability in a formation  underground, oil and / or gas producer according to which at least one injection is  a hydrocarbon producing well an aqueous gels composition in the  training around the producing well at adequate flow and / or pressure  and the well is returned to production, characterized in that said composition of  aqueous gels comprises a solution of at least one nonionic polysaccharide  and at least one complex based on polyvalent metal cations  water-soluble and cationically complexing organic acid, likely to  cross-linking said polysaccharide, said complex being at a concentration, expressed  by weight of metal dioxide, from 2 to 100 parts per million parts of the  solution. The process according to claim 1 wherein the nonionic polysaccharide is  selected from the group consisting of glucans, galactomannan gums and  their mixtures. The process according to claim 2 wherein the nonionic polysaccharide is  scleroglucan. 4. Method according to one of claims 1 to 3 wherein the metal cation  is zirconium and titanium. 5. Method according to one of claims 1 to 4 wherein the organic acid  complexing agent of the cation is an alphahydroxy acid and advantageously the acid  lactic acid or malic acid. 6. Method according to one of claims 1 to 5 wherein the molar ratio  lactic acid / zirconium is between 2 and 4. 7. Method according to one of claims 1 to 5 wherein the molar ratio acid  lactic / titanium is between 0.5 and 1.5. 8. Method according to one of claims 1 to 7 wherein the concentration of  complex is 5 to 25 ppm 9. Method according to one of claims 1 to 8 characterized in that it is applied  in case the water of the formation is at a temperature of 70 to 1300C. 10. Method according to one of claims 1 to 9 wherein the composition is  introduced at a flow rate and / or a pressure corresponding to a gradient of  shearing of at least 50 s-1 and the viscosity of the composition is less than  10 mPa.s shear gradient audit.