WO2021228546A1

WO2021228546A1 - Method for treating a subterranean formation comprising microorganisms

Info

Publication number: WO2021228546A1
Application number: PCT/EP2021/060953
Authority: WO
Inventors: Aline DELBOS; Yves Benoit
Original assignee: IFP Energies Nouvelles
Priority date: 2020-05-14
Filing date: 2021-04-27
Publication date: 2021-11-18
Also published as: FR3110173A1; FR3110173B1

Abstract

The present invention provides a method for treating a subterranean formation by injecting an aqueous solution that contains a biocidal chemical compound and a viscosifying polymer.

Description

PROCESS FOR TREATMENT OF UNDERGROUND TRAINING INCLUDING MICRO-ORGANISMS

Technical area

The present invention relates to the treatment of a subterranean formation against microorganisms (bacteria) colonizing the porous media of the subterranean formation. This treatment is indeed relevant in many applications related to the exploitation of natural underground reservoirs based on porous rock.

Among these applications, mention may be made of the exploration and exploitation of hydrocarbon wells, particularly with enhanced recovery of hydrocarbons (or EOR according to the English terminology for “Enhanced Oil Recovery”). We can also cite the geothermal recovery of underground fluids in porous rocks, or the storage of gas of the CH ₄ , H ₂ or C0 _{2 type} in porous rocks, for their subsequent use (H ₂ , CH ₄ ) OR for their trapping (C0 ₂ ).

In these three cases of figures, we have to inject or reinject fluids, gas or liquid, into porous rocks, and, from the start of the operation or by the very fact of these injections / reinjections of fluids implied by their operation, porous rocks can be the site of proliferation of microorganisms.

However, the accumulation or activity of microorganisms in these reservoir rocks is detrimental to their exploitation. Indeed, it has been observed that these microorganisms tend to form biofilms by the production of extracellular polymers, causing a significant reduction in the pore volume available to porous materials after colonization by these bacteria. (Throughout the present text, pore volume is understood to mean the volume of the porous material which is accessible to a fluid). This is referred to as biological clogging, which poses multiple problems: reduction of the volume available for fluid storage, pressure drops that can become prohibitive in the case of fluid injection, part of the porosity of the rock becoming inaccessible to fluids, reservoir of microorganisms which can subsequently re-colonize the environment. The microorganisms generally involved are in particular sulphate-reducing bacteria, which use the sulphate ions S0 ₄ ² as electron acceptors, which are transformed into sulphite ions, into sulphide and then into H ₂ S, which also promotes corrosion. circuits, materials and equipment used to the injection of fluid into these porous rocks (these phenomena are grouped together under the term of biological souring).

Prior art

This problem of formation of such biofilms has been observed in petroleum applications, and documented for example in the publication “Action of glutaraldehyde and nitrite against sulfate-reducing bacterial biofilms”, by Gardner LR, Stewart PS (J. Ind. Microbiol. Biotechnol. . (2002) 29: 354-360).

It has also been documented in the context of water reinjection in porous rocks for geothermal application, for example in the publication “Biofilm Forming Bacteria during Thermal Water Reinjection”, by Maté Osvald, Gergely Maréti, Bernadett Pap, and Jânos Szanyi Geofluids (Indawi Geofluids, Volume 2017, Article ID 9231056, January 2017).

There is therefore a need to fight against the proliferation of microorganisms in underground formations, and a first envisaged solution consists in treating the underground formations with chemical compounds called biocides, as mentioned in the aforementioned publication by LR Gardner et al.

However, the effectiveness of biocidal chemical compounds in porous materials in the presence of biofilms (especially in subterranean formation) is reduced, compared to that observed with cultures of free and planktonic microorganisms. As a result, the efficiency of the injection of a solution comprising biocidal chemical compounds is limited (bacteriostatic and non-bactericidal action).

On the one hand, this limitation in effectiveness is due to the organization of microorganisms into biofilms. This biofilm organization reduces the surface area accessible to flow in a porous medium, which limits the action of biocidal chemical compounds when they are injected into the porous medium.

On the other hand, this limitation is due to the viscosity of the solutions of biocides, which is close to that of water, which does not make it possible to reach the zones of the subterranean formation having the lowest permeability. These areas then form bacterial “niches”. Once the injection of such a biocidal solution is complete, these "niches" will play the role of permanent inoculum and lead (i) to a new colonization by the bacteria of the surrounding porous environment and (ii) to a resumption of their. activity. Summary of the invention

The object of the present invention is to effectively treat a subterranean formation, by eliminating the microorganisms present in the subterranean formation. To this end, the present invention relates to a method of treating a subterranean formation by injecting an aqueous solution which comprises a biocidal chemical compound and a viscosifying polymer. The viscosifying polymer makes it possible to viscosify the aqueous phase comprising the biocidal chemical compound, which makes it possible to contact during the injection of the aqueous solution the less permeable zones of the subterranean formation. Thus, the removal of bacterial colonies in the subterranean formation is more efficient. In addition, the process according to the invention makes it possible to limit the amount of biocidal chemical compounds injected into the underground formation, these compounds being harmful to the environment.

The invention relates to a method of treating a subterranean formation crossed by at least one injection well, microorganisms being present in said subterranean formation. In this process, the following steps are implemented: a) An aqueous solution is prepared comprising at least one biocidal chemical compound and at least one viscosifying polymer of said aqueous solution comprising said biocidal compound; and b) Treating said subterranean formation by injecting said aqueous solution into said injection well to remove said microorganisms.

According to one embodiment, said at least one biocidal chemical compound is chosen from THPS: tetrakis (hydroxymethyl) phosphonium sulfate, DBNPA 2,2-dibromo-3-nitrilopropionamide, alkyldimethyl benzyl coco chloride or glutaraldehyde, preferably said biocidal compound is glutaraldehyde

According to one implementation, said at least one viscosifying polymer is a hydrolyzed or partially hydrolyzed polyacrylamide HPAM: preferably said viscosifying polymer is suitable for the injection conditions, in particular the temperature and the salinity of the underground formation.

Advantageously, said aqueous solution comprises a mixture of glutaraldehyde and HPAM, or a mixture of alkyldimethyl benzyl coco chloride and HPAM, or a mixture of DBNPA and HPAM, preferably, said aqueous solution comprises a mixture of glutaraldehyde and HPAM adapted to the injection conditions, in particular the temperature and the salinity of the underground formation.

According to one aspect, said aqueous solution comprises a concentration of said at least one biocidal chemical compound of between 60 and 1500 ppm, preferably between 1000 and 1500 ppm for glutaraldehyde. According to one embodiment, said aqueous solution comprises a concentration of said at least one viscosifying polymer of between 0.1 g / L and 10 g / L, preferably 1 g / L.

According to one characteristic, the viscosity of said aqueous solution before injection is greater than the viscosity of the brine injected at the temperature and salinity of said subterranean formation.

According to one option, an amount of aqueous solution is injected into said subterranean formation to perform a sweep of said subterranean formation between said injection well and a second well passing through said subterranean formation.

In addition, the invention relates to a method for enhanced recovery of hydrocarbons within an underground formation through which at least one injection well passes. For this process, the following steps are implemented: a) said underground formation is treated by means of the treatment process according to one of the preceding characteristics, b) an enhanced hydrocarbon recovery fluid is injected into said treated underground formation; and c) Hydrocarbons are produced from said subterranean formation.

The invention also relates to a method for geothermal recovery of underground fluids within an underground formation crossed by at least one injection well. For this process, the following steps are implemented: a) said underground formation is treated by means of the treatment process according to one of the preceding characteristics; b) said underground fluid present in said treated underground formation is recovered; and c) energy is generated from said recovered underground fluid.

In addition, the invention relates to a process for storing gas in an underground formation through which at least one injection well passes. For this process, the following steps are implemented: a) said underground formation is treated by means of the treatment process according to one of the preceding characteristics; and b) said gas to be stored is injected into said treated underground formation.

Description of embodiments

First of all, it should be remembered that bacteria are unicellular microorganisms and are therefore generally not organized into tissues. Each bacteria grows and divides independently of any other bacteria, although aggregates of bacteria, sometimes containing members of different species, are frequently found. There are several types of bacteria classified into genera and species, which vary according to their shapes and colors or even their growing conditions.

In nature, many organisms live in communities (eg biofilms) which can provide increased nutrient supply and protection against environmental stresses. Microorganisms in biofilms often exhibit very different properties of the same organism in the individual or planktonic state. Bacteria that have aggregated in biofilms can provide information about the nature of the population and its metabolic status.

In the laboratory, bacteria are usually grown in solid or liquid media. Solid growth media (agar agar) prepared in petri dishes are used to isolate a bacterial strain from mixed cultures. In addition, liquid growth media are also used when measurement of growth or large volumes of cells are required. Growth in stirred liquid media occurs as often uniform cell suspensions, which facilitate the division and transfer of gases (especially oxygen) into the culture reaction medium. The use of selective media (media with specific added or deficient nutrients, or containing antibiotics) can help identify and / or isolate specific organisms.

Most laboratory techniques for studying bacterial growth use high levels of nutrients to produce large amounts of cells inexpensively and quickly. However, in natural environments some of these nutrients are limited, which means bacteria cannot reproduce indefinitely. This nutrient limitation has led to the evolution of different growth strategies. Bacterial growth in fact follows four phases, the entry for the first time into a nutrient-rich environment of a population of bacteria will allow its growth:

The first phase I is the lag phase, characterized by a period of slow growth during which the cells adapt to the environment rich in nutrients. The lag phase is associated with high rates of biosynthesis because the proteins necessary for rapid growth are produced. - The second phase of growth II is called exponential phase, marked by rapid exponential growth. During this phase, each bacterium generates two daughter bacteria, by binary scission, in each generation. One of the physical parameters linked to this growth is the rate of growth of the cells during said phase, and the time required for the cells to double, called generation time. During the exponential phase, nutrients are metabolized at maximum speed until one of the nutrients is depleted and begins to restrict growth.

- The third growth phase III is the stationary phase which is caused by nutrient deficiency. Cells reduce their metabolic activity (the number of cells that appear equals the number of cells that disappear).

Final phase IV is the phase of mortality due to nutrient depletion.

It has been observed that the hydraulic permeability of a porous material can be reduced by up to three or four orders of magnitude due to the formation of biofilm within the available porosity of the material. Thus, during phase I of growth, it has been observed that the microorganisms occur either in isolation at the "pore walls - liquid phase" interface, or in small colonies. Then, in the second phase II, a rapid decrease in permeability is observed, the saline liquid in the pores is partially replaced by:

- The presence of biological bodies: exopolysaccharides (EPS), biofilm or aggregates of bacteria.

The formation of gas bubbles caused by the excessive saturation of the aqueous solution with gaseous products generated by the biological activity of microorganisms, such as C0 ₂ and CH ₄ .

- The precipitation of insolubles in the form of salts, such as sulfuric iron formed by microorganisms using a sulfate anion as an electron acceptor

A combination of at least two of the above compounds.

In a first hypothesis, called a “closed pore model”, the pores become completely blocked by the porous and permeable biofilms, and the minimum value of the permeability of the porous material corresponds to the intrinsic permeability of the biofilm.

In a second hypothesis, called “open pore model”, the shear stress exerted by the fluid on the biofilm causes the continuous detachment of the biofilm fragments and, consequently, the pores are never completely blocked; here the minimum value of the permeability of the porous material is determined by the balance between growth and detachment.

During the last phase IV, we observe the partial recovery (due to the presence of biofilms which are made up of very viscous polymers often difficult to completely sweep away), or complete recovery of the permeability (if a limiting factor comes to stop the growth cellular).

It is from these observations that the inventors have developed a process for treating an underground formation with a suitable solution having a biocidal action on these microorganisms in a porous medium, taking into account the particularities of these mediums. porous.

For this purpose, the present invention relates to the treatment of a subterranean formation, in which microorganisms are found. At least one injection well passes through the underground formation. Treatment of a subterranean formation is understood to mean the removal of microorganisms within the subterranean formation. Treatment of the subterranean formation can be preventive (ie before bacteria appear) or curative (ie after bacteria appear). The method according to the invention comprises the following steps:

Preparation of an aqueous solution, preferably in liquid form, comprising at least one biocidal chemical compound and at least one viscosifying polymer of the aqueous solution which comprises the biocidal chemical compound, and Injection into the subterranean formation through the injection well of the aqueous solution, the aqueous solution having the aim of eliminating the microorganisms present in the subterranean formation.

The viscosifying polymer makes it possible to viscosify the aqueous phase comprising the biocidal chemical compound (in other words, the viscosifying polymer is chosen to viscosify the aqueous phase which comprises the biocidal chemical compound), which makes it possible to penetrate during the injection of the aqueous solution the less permeable areas of the subterranean formation. Thus, the elimination of bacterial colonies in a porous medium is more efficient. In addition, the process according to the invention makes it possible to limit the quantity of biocidal chemical compounds injected into the subterranean formation, these chemical compounds being harmful to the environment. By its biocidal action against bacteria, the process according to the invention also makes it possible to limit the quantity of H ₂ S formed by the sulphate-reducing bacteria which may be present in the underground formation. Advantageously, the viscosifying polymer can be in the form of a powder added to the aqueous solution. Preferably, the aqueous solution is not in the form of a gel. Indeed, a gel does not allow deep injection or sweeping of the subterranean formation, which does not allow the expected biocidal effect to be obtained.

In the case where the underground formation does not include an injection well, the method of treating the underground formation may include a preliminary step of drilling such an injection well.

Alternatively, the method of treating the underground formation can comprise a preliminary stage of conversion, temporary or definitive, of a production well (for example in the case of the recovery of hydrocarbons, or in the case of a geothermal application) into an injection well.

The preparation of the aqueous solution can be carried out outside the injection well, preferably near the injection well.

In addition, the aqueous solution may include compounds neutral to the process, for example salts initially present in the water used.

In addition, the aqueous solution can be adapted to the nature of the subterranean formation, in particular to the pH, to the temperature, to the salinity and to the permeability of the subterranean formation, by adapting in particular the compounds, their concentrations, etc.

According to one embodiment of the invention, the biocidal chemical compound can be chosen from:

THPS: tetrakis (hydroxymethyl) phosphonium sulfate (from the English Tetrakis (Hydroxymethyl) Phosphonium Sulfate) is a microbicide used for the treatment of water, which can inhibit the microbial growth of most aerobic or anaerobic microorganisms, microorganisms that form a biofilm in enhanced oil recovery processes, production systems and water injection in underground wells. THPS is characterized by its low strength point and good stability, it can easily dissolve in water and has a long shelf life.

DBNPA: 2,2-dibromo-3-nitrilopropionamide DBNPA has a bactericidal effect on all aerobic bacteria in free culture, the reaction time for this type of biocide is quite short (10 minutes).

Glutaraldehyde (or Pentane-1, 5-dial) is used in several fields of application, it is a very stable product (for a pH between 4 and 7). In free culture medium, it instantly inhibits all anaerobic bacteria present for a concentration of 1000 ppm. Alkyldimethyl benzyl coco chloride (from the English benzylcoco alkyldimethyl chloride), recommended for its dual effectiveness as a biocide and detergent.

Biocides can, depending on the type and concentration used, have a bacteriostatic (partial inhibition) or bactericidal (death of bacteria) effect.

Preferably, the process according to the invention can use the chemical biocidal compound glutaraldehyde or THPS in solution selected for their compatibility in solution with the polymers, and the fact that they make it possible to maintain the viscosity of the polymer sufficiently high for the process. .

In accordance with one implementation of the invention, the viscosifying polymer can be chosen from HPAM: hydrolyzed or partially hydrolyzed polyacrylamide, the polymer having to be chosen according to the injection conditions (temperature, salinity of the water). injection) so that the viscosity is not reduced during injection.

In fact, these polymers exhibit viscosifying and shear-thinning properties, making it possible to promote the penetration of the aqueous solution into porous media, including for porous media of low permeability.

Preferably, the aqueous solution can comprise a mixture of:

- Glutaraldehyde and HPAM, in fact for this aqueous solution the viscosity remains close to the viscosity of an aqueous solution comprising HPAM at 82 ° C in anaerobic condition, which favors the effect of the injection of an aqueous solution , or alkyldimethyl benzyl coco chloride and HPAM, in fact for this aqueous solution the viscosity remains close to the viscosity of an aqueous solution comprising HPAM at 82 ° C in anaerobic condition, which promotes the effect of injection of an aqueous solution

According to one embodiment of the invention, the aqueous solution can comprise a concentration of biocidal chemical compound of between 60 and 1500 ppm by weight, preferably between 125 ppm and 1500 ppm, and very preferably between 125 and 100Oppm. These ranges make it possible to ensure the elimination of bacteria present in the underground formation, while limiting the harmful effects of these biocidal compounds. In particular, when the biocidal compound is THPS, its concentration in the aqueous solution can be between 60 and 200 ppm. Indeed, it has been shown that from 60 ppm (mg / l) and under planktonic conditions, THPS has an immediate and very effective bactericidal action on the microbial growth of sulfato-reducing and methanogenic bacteria.

When the biocidal compound is DBNPA, its concentration in the aqueous solution can be between 200 and 400 ppm.

When the biocidal compound is glutaraldehyde, its concentration in the aqueous solution can be between 1000 and 1500 ppm.

When the biocidal compound is alkyldimethyl benzyl coco chloride, its concentration in the aqueous solution can be between 500 ppm and 1000 ppm. In fact the has been shown to be bactericidal against anaerobic SRB bacteria from 500ppm

According to one aspect of the invention, the aqueous solution may comprise a concentration of viscosifying polymer of between 0.1 g / L and 10 g / L in concentration, preferably between 1 g / L and 5 g / L. These concentration ranges make it possible to ensuring the viscosity of the aqueous solution comprising the biocidal chemical compound.

In particular, when the viscosifying polymer is HPAM, its concentration in the aqueous solution can be between 1 g / L and 5 g / L

For the embodiment, for which the aqueous solution comprises glutaraldehyde as a biocidal compound, and HPAM as a viscosifying polymer, the concentration of glutaraldehyde may be between 1000 and 1500 ppm, and the concentration of HPAM may be between between 1 and 5 g / L. This aqueous solution has both an optimum viscosity for penetrating the subterranean formation, and a biocidal effect on bacteria.

In order to promote the effect of the aqueous solution, the viscosity of the aqueous solution before injection is greater than the viscosity of the brine (present in the underground formation) at the temperature of the underground formation, the viscosity being measured by a method of measurement such as the rheometer at the temperature of the subterranean formation. Thus, the viscosity of the aqueous solution depends on the porous medium. According to one implementation of the invention, the injection of the aqueous solution can be provided to carry out a sweeping of the underground formation, in this way a large part of the underground formation is treated by the method according to the invention and not just around the well. This is allowed by the viscosity of the aqueous solution and the amount of aqueous solution injected into the fluid. Thus, for this implementation, the quantity of aqueous solution injected into the fluid can be predetermined to carry out a sweep of the underground formation from the injection well towards a second well passing through the underground formation. The second well passing through the underground formation can be a production well (in the context of the recovery of hydrocarbons, or in the context of a geothermal application).

The treatment method according to the invention can be applied to several fields related to the exploitation of the underground formation: the recovery of hydrocarbons, in particular the enhanced recovery of hydrocarbons (EOR), geothermal recovery, gas storage, etc. .

To this end, the invention also relates to an enhanced hydrocarbon recovery (EOR) process within an underground formation crossed by at least one injection well and one hydrocarbon production well. For this method, the following steps can be implemented:

- Treatment of the underground formation by means of any of the variants or combinations of variants of the method for treating the underground formation described above,

Injection through the injection well (which may be identical or different from the injection well used in the previous step) into the treated underground formation of an enhanced hydrocarbon recovery fluid,

Recovery by the producing well of the hydrocarbons present in the underground formation.

Such an enhanced hydrocarbon recovery fluid is well known to specialists, and may contain in particular polymers such as HPAM, foams, such as C0 ₂ foams, alkalis, surfactants, mixtures of these compounds, etc. The purpose of such a fluid is to promote the recovery of hydrocarbons.

In addition, the present invention relates to a method for geothermal recovery of an underground fluid originating from an underground formation crossed by at least one injection well. For this method, the following steps can be implemented: - Curative or preventive treatment of the underground formation by means of any one of the variants or combinations of variants of the method for treating the underground formation previously described,

- Recovery of the underground fluid from the underground formation treated by a well crossing the underground formation (which may be identical or different from the injection well used in the previous step), and

- Generation of energy from underground fluid.

The step of generating energy from the underground fluid may in particular consist first of all in the generation of water vapor, then in the generation of electricity by means of a turbine driven by the water vapor. 'water.

In addition, the present invention relates to a method for storing gas, for example CO ₂ , CH ₄ , OR H ₂ in an underground formation. The underground formation includes at least one gas injection well. For this method, the following steps can be implemented:

- Curative or preventive treatment of the underground formation by means of any of the variants or combinations of variants of the treatment process of the underground formation described above,

Injection of said gas to be stored in the underground formation treated by means of the injection well (which may be identical or different to the injection well used in the previous step).

This process can therefore be implemented in a process for capturing and storing (trapping) C0 ₂ . In the context of CH ₄ and H ₂ , the storage of this gas can be temporary, until their subsequent use. For these gases, the process can then include an additional step of withdrawing the stored gas from the underground formation. Treatment of the underground formation can then be provided between each withdrawal and each injection of the gas or at regular time intervals, in order to ensure the elimination of bacteria within the underground formation.

Examples

The characteristics and advantages of the process according to the invention will emerge more clearly on reading the application examples below.

Example 1 We note by analogy with the oil sweeping efficiencies in an underground formation by a polymer solution in a porous medium, that:

- The addition of HPAM polymer in an aqueous solution makes it possible to increase the viscosity of the water, for example for an aqueous solution comprising HPAM 3630s at 2g / L (molecular mass approximately 20 MDa), the viscosity of the solution aqueous is 31 times that of softened sea water (without HPAM polymer), and The addition of HPAM polymer in an aqueous solution makes it possible to increase the flushing, for example for an aqueous solution comprising HPAM 3630s at 2g / L , the sweeping of the subterranean formation is improved by 82% compared to a sweep with soft sea water (without HPAM polymer).

Thus, the aqueous solution used in the process according to the invention has a viscosity suitable for sweeping the porous medium which constitutes the underground formations.

Claims

1. A method of treating an underground formation crossed by at least one injection well, microorganisms being present in said underground formation, characterized in that the following steps are implemented: a) a solution is prepared. aqueous comprising at least one biocidal chemical compound and at least one viscosifying polymer of said aqueous solution comprising said biocidal compound; and b) Treating said subterranean formation by injecting said aqueous solution into said injection well to remove said microorganisms.

2. A method of treating a subterranean formation according to claim 1, wherein said at least one biocidal chemical compound is selected from THPS: tetrakis (hydroxymethyl) phosphonium sulfate, DBNPA 2,2-dibromo-3-nitrilopropionamide, alkyldimethyl benzyl coco chloride or glutaraldehyde, preferably said biocidal compound is glutaraldehyde

3. A method of treating a subterranean formation according to one of the preceding claims, in which said at least one viscosifying polymer is a hydrolyzed or partially hydrolyzed polyacrylamide HPAM: preferably said viscosifying polymer is suited to the injection conditions, in particular to the temperature and salinity of the subterranean formation.

4. A method of treating a subterranean formation according to claims 2 and 3, wherein said aqueous solution comprises a mixture of glutaraldehyde and HPAM, or a mixture of alkyldimethyl benzyl coco chloride and HPAM, or a mixture of DBNPA. and HPAM, preferably, said aqueous solution comprises a mixture of glutaraldehyde and HPAM suitable for the injection conditions, in particular the temperature and the salinity of the subterranean formation.

5. A method of treating a subterranean formation according to one of the preceding claims, wherein said aqueous solution comprises a concentration of said at least one biocidal chemical compound of between 60 and 1500 ppm, preferably between 1000 and 1500 ppm for glutaraldehyde. .

6. A method of treating a subterranean formation according to one of the preceding claims, wherein said aqueous solution comprises a concentration of said at least one viscosifying polymer of between 0.1 g / L and 10 g / L, preferably 1 g. /THE.

7. A method of treating a subterranean formation according to one of the preceding claims, in which the viscosity of said aqueous solution before injection is greater than the viscosity of the brine injected at the temperature and salinity of said subterranean formation.

8. A method of treating a subterranean formation according to one of the preceding claims, in which a quantity of aqueous solution is injected into said subterranean formation in order to sweep said subterranean formation between said injection well and a second through well. said underground formation.

9. Process for enhanced recovery of hydrocarbons within an underground formation crossed by at least one injection well, characterized in that the following steps are implemented: a) said underground formation is treated by means of the process of treatment according to one of the preceding claims, b) an enhanced hydrocarbon recovery fluid is injected into said treated subterranean formation; and c) Hydrocarbons are produced from said subterranean formation.

10. A method of geothermal recovery of underground fluids within an underground formation crossed by at least one injection well, characterized in that the following steps are implemented: a) said underground formation is treated by means of the process treatment according to one of claims 1 to 8; b) said underground fluid present in said treated underground formation is recovered; and c) energy is generated from said recovered underground fluid.

11. Process for storing gas in an underground formation crossed by at least one injection well, characterized in that the following steps are implemented: a) said underground formation is treated by means of the treatment process according to one of the following steps: claims 1 to 8; and b) said gas to be stored is injected into said treated underground formation.