Membrane for the insertion of a porous material

Abstract

The present invention relates to a membrane for the insertion of a porous material (6), said membrane (1) comprising a cylindrical sleeve (2), said sleeve comprising a metal layer (3) disposed between a first and a second polymer layer (4, 5). Figure 1 to be published

Description

Title of the invention: Membrane for inserting a porous material Technical field

[0001] The present invention relates to the field of experiments for porous media, such as rocks, in particular for applications related to subsoil exploitation: geothermal energy, hydrocarbon recovery, gas storage, etc. It is of particular interest to all technologies aimed at storing gases such as carbon dioxide or hydrogen in underground geological reservoirs, and in particular technologies known by the acronym CCUS (for "Carbon Capture Utilization and Storage" in English) or by the acronym CSCV in French (for Captage, Stockage et Valorisation du Carbone) aimed at capturing and storing carbon dioxide emitted by industrial installations underground. It should be noted that the gases in question may be in the gas phase or be dissolved in the liquid phase.

[0002] For these applications related to subsoil exploitation, it is customary to carry out experiments on rocks taken from an underground formation. For these experiments, a rock sample can be placed in a membrane, in particular a cylindrical membrane, and the physical phenomena within the rock sample are analyzed. The cylindrical membrane forms a waterproof envelope around the rock sample. Such a membrane is generally made of polymer. An example of an experiment consists of circulating a fluid in the rock sample, the fluid being able to be a fluid initially present in the underground formation or a fluid to be injected into the underground formation. These experiments can be carried out at different temperatures or at different pressures.

[0003] In other fields, it is also desirable to carry out porous medium experiments, for example in the pharmacological field, or in the agri-food field.

[0004] In order to analyze the physical phenomena of these experiments, the membrane is generally instrumented with different sensors, for example with pressure sensors, temperature sensors, flow meters, etc. To best understand these physical phenomena, it is preferable to have several measurement points along the porous medium. Prior art

[0005] Currently, measurements along the membrane are made possible by positioning metal inserts along the cylindrical membrane. These metal inserts are provided for connecting the sensors.

[0006] These inserts can be overmolded onto the polymer membrane. The overmolding technique is an interesting technique, but it has certain drawbacks: it requires the precise definition of the position of the inserts, it is quite long to operate, and it does not allow the removal of the inserts without destroying the cylindrical sleeve (consequently the inserts remain immobilized on the membrane even when the membrane is not in use).

[0007] Patent FR3122732 proposes an improvement in the way of integrating inserts, by proposing a membrane comprising a cylindrical sleeve and at least one metal insert, and which comprises clamping means, a retaining means and a hollow rod. This design allows removable fixing of the metal insert, without the need for an expensive and lengthy overmolding step.

[0008] The design of such membranes is, moreover, still susceptible to improvement. Indeed, their conditions of use can be very restrictive, in particular because they may have to withstand high pressures and / or high temperatures, or because they may come into contact with a corrosive environment, in particular when the circulating fluid used includes high salt contents (brine). And these extreme conditions can weaken the membrane, damaging it to the point of leakage.

[0009] The invention then aims to improve the design of these membranes, in particular with a view to improving their robustness, whatever the operating conditions in which measurements are carried out (pressure, temperature, nature of the circulating fluid, etc.), and this preferably without making their manufacture too complex. Summary of the invention

[0010] The invention firstly relates to a membrane for inserting a porous material, said membrane comprising a cylindrical sleeve, and such that said sleeve comprises a layer of metal disposed between a first and a second layer of polymer.

[0011] The term “sleeve” is understood to mean a portion of a hollow cylinder having a certain wall thickness.

[0012] It has indeed been found that a three-layer sleeve design (at least) allows the membrane to withstand much better severe operating conditions, in particular high pressures, high temperatures, and very corrosive circulating fluid compositions, in particular with high salinity conditions, and even in the case where at least two of these conditions are met, such as a high temperature combined with a very high salinity of the circulating fluid.

[0013] High temperatures are understood to mean temperatures which can be at least minus 50°C, in particular at least 100°C and even beyond 120 or even up to 150°C and beyond. High pressures are understood to mean pressures such that the confining pressure may be higher than the pore pressure, in particular by at least 5 bars (5.105 Pa) or at least 10 bars (106 Pa) or at least 15 bars (1.5.106 Pa) and up to 20 bars (2.106 Pa) and beyond. The so-called confining pressure is the pressure measured outside the membrane, the so-called pore pressure is the pressure inside the membrane: the higher the pressure difference, the higher the mechanical stresses on the membrane will be. High salinity conditions are understood to mean concentrations of salt(s), particularly sodium chloride, of at least 100 g / l, particularly at least 200 g / l, and up to 300 g / l and beyond. It is in fact by the combination of these three layers that we obtain these good results: The metal layer can thus serve as a gas barrier layer, while being protected from corrosion by the two polymer layers between which it is placed. And the polymer layers make it possible to absorb a certain deformation during use of the membrane (when the porous material to be analyzed is inserted in particular) and protect the metal layer, preserving its integrity, and also participate in the barrier effect to fluids ensured by the metal layer. It is therefore the set of three layers that ensures the sleeve is perfectly impermeable to gases, which makes it possible to solve the problem of increased risks of gas fugacity through the sleeve when the operating temperature is high. Indeed, it has been observed that the higher the operating temperature, the more the gas fugacity increases, and the greater the differences between the quantity of gas injected into the sample to be analyzed introduced into the sleeve and the quantity of gas at the outlet. The design of the sleeve with these three layers makes it possible to considerably reduce this difference.

[0014] It is recalled that the fugacity of a gas is calculated from the pressure, the temperature, and the composition of the medium. Fugacity is very close to chemical activity: it reflects the capacity of a species to interact, with itself or with other components, within the same medium. For an ideal gas, fugacity is equal to pressure. Nitrogen is close to the behavior of an ideal gas, its fugacity is even slightly higher than its pressure. Most other gases have a fugacity lower than their pressure. CO2, condensable, can have a fugacity much lower than its pressure. Fugacity governs the impact of a species on physicochemical mechanisms. It is the driving force behind many physical phenomena such as diffusion, chemical reaction, corrosion, etc.

[0015] Preferably, the metal layer is chosen from at least one of the metals or following alloys: aluminum, steel, especially stainless steel.

[0016] Preferably, the thickness of the metal layer is between 20 μm and 200 μm, in particular between 50 and 150 μm. It may, for example, be in the vicinity of 100 μm. This range of thicknesses makes it possible both to ensure gas tightness and to present a certain mechanical strength while allowing easy shaping.

[0017] Preferably, at least one of the polymer layers, in particular the two polymer layers, comprise at least one elastomer, in particular chosen from at least the following polymers: fluoroelastomers (FKM), perfluoroelastomers (FFKM), copolymers of butadiene-acrylonitrile type, hydrogenated or not (NBR or HNBR). These are in fact polymers capable of withstanding high temperatures and pressures without degradation; they are very chemically inert polymers.

[0018] Preferably, the thickness of at least one of the polymer layers, in particular of the two polymer layers, is between 100 μm and 400 μm, in particular between 200 μm and 300 μm. Their thicknesses are preferably identical or similar. Their thickness may, for example, be in the region of 250 μm.

[0019] Preferably, the total thickness of the metal layer and the two polymer layers is at most 8 mm, in particular at most 7 mm, and is preferably between 4 and 6 mm. With this total thickness range, the sleeve has the desired strength, deformability and gas impermeability.

[0020] Preferably, the internal diameter of the sleeve is between 23 and 50 mm, in particular between 40 and 50 mm.

[0021] Preferably, the length of the sleeve (measured along the longitudinal axis of the cylinder portion) is between 100 and 450 mm, in particular between 150 and 250 mm.

[0022] Preferably, a means is provided ensuring adhesion between at least one of the polymer layers and the metal layer, in particular in the form of an adhesive. The adhesive may be arranged in the form of discontinuous adhesive dots or in the form of an at least partially continuous film between the polymer layer and the metal layer. It is preferably chosen to withstand high temperatures. It may be so-called epoxy adhesives, based on polychloroprene, or silicone or cyanoacrylate type. It may also be adhesives in the form of films.

[0023] Preferably, the membrane comprises at least one metal insert arranged in an orifice of said cylindrical sleeve for connection to a measuring system.

[0024] In a first variant, the insert can be overmolded, in particular on the second layer of polymer (the outer layer of the sleeve) or on an additional layer of polymer arranged thereon.

[0025] In a second variant, the insert can be integrated into the sleeve according to the teaching of patent FR3122732 to which reference will be made for more details. In this variant, the insert comprises means for clamping a portion of said cylindrical sleeve, means for retaining said clamping means, and a hollow rod for connection with a measuring system, said hollow rod passing through said cylindrical sleeve and being fixed to said clamping means. Still in this second variant, according to one embodiment, said clamping means comprise a lower jaw arranged inside said cylindrical sleeve, and an upper jaw arranged outside said cylindrical sleeve. Advantageously, said lower jaw comprises at least one protruding shape directed towards the outside of said cylindrical sleeve, and said upper jaw comprises at least one hollow shape capable of cooperating with said protruding shape of said lower jaw, preferably said protruding shape has a substantially annular shape. Advantageously, said retaining means is a nut bearing on said upper jaw, said nut being screwed onto a threaded tube connected to said lower jaw. Preferably, said hollow rod is screwed inside said threaded tube connected to said lower jaw. According to one implementation, said insert comprises a connector, in particular a connector for a pressure sensor, and / or for a temperature sensor, and / or for an optical fiber. According to one aspect, said connector is substantially perpendicular to said hollow rod. According to an embodiment option, said connector is held on said hollow rod by means of a circlip.

[0026] The invention also relates to a method for manufacturing the membrane described above. According to one embodiment, this method is such that: - a first cylindrical sleeve is produced with the first layer of polymer, by molding and extrusion - we cover this first sleeve with a metal sheet to create the metal layer - polymer is deposited, in particular by extrusion, on the metal layer to create the second polymer layer.

[0027] The first polymer layer may be shaped to form a hollow cylinder portion by a molding or extrusion or grinding technique.

[0028] The metal sheet may be folded / rolled around the first layer once shaped into a portion of a cylinder, preferably so as to have an edge-to-edge overlap, and preferably after applying a glue / adhesive to the outer surface of the first polymer layer once shaped and / or to the face of the metal sheet intended to be in contact therewith, either in the form of glue dots or in the form of a film. The metal sheet is then also shaped into cylinder.

[0029] The second layer can be applied to the metal sheet once shaped, by extrusion of the polymer in the liquid / semi-liquid state, so as to constitute the three-layer sleeve, with or without intermediate adhesive.

[0030] The invention also relates to a method for analyzing the flow of a fluid in a porous medium which implements the following steps: - Said porous medium is inserted into the membrane as described above and provided with at least one insert, - Said at least one insert of said membrane is connected to a measuring installation, and - A fluid is circulated in said porous medium, and - A measurement is carried out by means of said measuring installation during said circulation of said fluid.

[0031] Preferably, this analysis method is such that: - said porous medium is a rock, - said fluid is a fluid injected or present in an underground formation, - and the measuring step implements a measurement of the pressure and / or the temperature at the level of said insert of said membrane.

[0032] Other characteristics and advantages of the device according to the invention will appear on reading the following description of non-limiting examples of embodiment, with reference to the appended figures described below. List of figures

[0033] [Fig.l] [Fig.l] represents, in a cross-sectional plane of the membrane, a sleeve according to the invention. It does not necessarily respect the scale, in particular between the different layers constituting the sleeve, in order to facilitate reading. Description of the embodiments

[0034] The present invention relates to a membrane for inserting a porous material. The membrane is intended to envelop the porous material for the purpose of analyzing the porous material, in particular for analyzing flows within the porous medium.

[0035] The membrane is configured to be clamped around the porous medium, and to form an impermeable layer around the porous medium.

[0036] The porous medium may be a rock sample taken from an underground formation, a polymeric material, a metallic material, a ceramic material, or any similar material.

[0037] As shown in [Fig.l], the membrane 1 according to the invention comprises a cylindrical sleeve 2, the porous medium being intended to be inserted inside the cylindrical sleeve (the porous medium therefore has a substantially cylindrical shape). The sleeve comprises a layer of metal 3 between two layers 4,5 of polymers, the set of three layers providing the sleeve with a certain deformability allowing the sample to be inserted, but also very high impermeability to gases and sufficient mechanical strength even at high temperatures (at least 50, 100, 120 or even 150°C) and at high pressure (up to 300 bar relative and 100 bar differential pressure).

[0038] It is planned to integrate into the sleeve a metal insert (not shown in [Fig.l]), which can either be overmolded onto the second layer 5 of polymer (according to the principle of [Fig.l] of patent FR3122732), or inserted as described in patent FR3122732, and in particular as shown in figures 2 to 5 of said patent. This metal insert is, whatever its mode of integration into the sleeve, arranged in an orifice of the cylindrical sleeve for connection to a measuring system. The orifice of the cylindrical sleeve is an orifice in the radial direction of the cylindrical sleeve. The metal insert can be installed at any point of the cylindrical sleeve. The metal insert allows the connection of a measuring system to carry out measurements for the analysis of the porous medium at the insert.

[0039] The insert may also comprise a connector (also not shown in [Fig.l]), in particular a connector for a pressure sensor, or a connector for a temperature sensor, or a connector for an optical fiber, or any similar measuring means. The connector may be mounted on the free end of the hollow rod of the insert assembly according to patent FR3122732. The connector allows the fluid connection between the bore of the rod and the sensor or the optical fiber. In order to limit the lateral bulk, the connector may be arranged perpendicular to the hollow rod. Alternatively, the connector may be arranged in continuity with the axis of the hollow rod. For this embodiment, the bore of the hollow rod may be longitudinal within the hollow rod. The connector may be held on the hollow rod by any means, in particular by a circlip (retaining ring), screws, clipping means, a bayonet assembly, etc. These support means are removable.

[0040] The membrane according to the invention may comprise several metal inserts, so as to be able to carry out measurements at several points of the porous medium.

[0041] In order to ensure the sealing of the insert, the insert may comprise sealing means, in particular sealing gaskets.

[0042] According to the invention, the method for analyzing the flow of a fluid in a porous medium can implement the following steps: - A porous medium is inserted into a membrane as described previously, - At least one insert of the membrane is connected to a measuring system, - At least one fluid is circulated in the porous medium (between the two ends of the porous medium not covered by the membrane) and a measurement is taken using the measuring system. Thus, the analysis method makes it possible to carry out a measurement at a desired point during a flow in a porous medium, in particular a measurement of pressure and / or temperature in said porous medium.

[0043] According to one embodiment, the porous medium may be a rock sample taken from an underground formation. Thus, it is possible to carry out measurements representative of the physical phenomena implemented in an underground formation. Alternatively, the porous medium may be a polymer material, a metallic material, a ceramic material or any similar material.

[0044] In one aspect, the injected fluid may be a fluid to be injected into a subterranean formation or a fluid present in a subterranean formation. Examples of fluids to be injected into a subterranean formation may be an acid gas such as carbon dioxide CO2, a geothermal fluid, an enhanced oil recovery (EOR) fluid, etc. Examples of fluids present in a subterranean formation may be water, brine, liquid or gaseous hydrocarbons, etc.

[0045] Thus, the method using the membrane according to the invention can determine the behavior of these fluids in an underground formation. For the field of exploitation of an underground formation (geothermal energy, gas storage, hydrocarbon recovery, etc.), the method according to the invention can be implemented for a rock sample, for a fluid to be injected or present in an underground formation, and the measurement can be a temperature or pressure measurement.

[0046] Alternatively, the fluid may be a pharmaceutical or food processing fluid.

[0047] Example 1 The cylindrical sleeve 2 according to a non-limiting example of the present invention comprises at least three layers: - a layer of metal 3, 100 pm, which can be aluminum or stainless steel, preferably stainless steel, which is inserted between - a first layer of polymer 4 of 250 μm, chosen from fluoroelastomers (FKM), perfluoroelastomers (FFKM), copolymers of butadiene-acrylonitrile type, hydrogenated or not (NBR or HNBR), ethylene-propylene-diene monomers (EPDM), or any similar polymer capable of withstanding temperatures of at least 50 or 100 °C and pressures of at least 300 bars (3.105Pa) without degradation. Preferably, Viton is chosen, a trade name corresponding to a fluoroelastomer. - and a second layer of polymer 5, identical in its thickness and nature chemical at first. Naturally, according to other embodiments, polymer layers with different thicknesses or polymer natures can be chosen. Between the first polymer layer 4 (the innermost) and the metal layer 5, an adhesive is provided (not shown), in particular an epoxy type glue distributed according to glue points distributed on the external surface of the first polymer layer. The sleeve 2 thus formed has an external diameter of 50 mm, an internal diameter of 40 mm and a length of 250 mm.

[0048] It was manufactured as follows: - the first layer of polymer 4 is formed by molding or extrusion into a hollow cylinder, - glue dots are placed on its external surface - a sheet of metal is wrapped around this first layer to form the metal layer 3, so that a longitudinal edge relative to the axis of the cylinder formed by the sleeve covers the opposite longitudinal edge by at least 2 mm - the second layer 5 of polymer is poured onto the metal layer 3 by extrusion.

[0049] It is then planned to overmould a metal insert onto the polymer layer 5 which will enable pressure and temperature measurements to be taken by connection with ad hoc sensors.

[0050] Mechanical strength tests under test conditions of the sleeve according to the invention were carried out under the following conditions: - Placement of a rock in the membrane - Assembly of the cell then putting under confinement pressure at 15 bar (1.5.106 Pa) - Simultaneous increase of the confining pressure to 80 bars (8.107 Pa) and the pore pressure to 3 bars (3.105 Pa) - Permeability measurement at 40°C - Increase the temperature to 120°C - Waiting time of approximately 48 hours - Pressure drop to ambient P - Temperature drop from 120°C to room temperature - Disassembly The porous medium was always kept under flow.

[0051] After disassembly, visual observation did not reveal any modification of the integrity of the membrane: no cutting of the external layer 5 of polymer by the metal sheet 3 was observed. No preferential passage between the membrane and the rock sample was observed: no loss of sealing of the sleeve in its together. The three-layer sleeve according to the invention therefore retains its integrity and its barrier capacity to fluids, particularly gases, even under severe operating conditions (high pressure / high temperature).

[0052] Two-layer sleeves, with only one layer of polymer topped with a layer of metal, did not achieve such good results under harsh conditions: losses of sealing were observed under the same test conditions, at high temperature and / or high pressure.

Claims

Claims

1. Membrane for inserting a porous material (6), said membrane (1) comprising a cylindrical sleeve (2), characterized in that said sleeve comprises a layer of metal (3) arranged between a first and a second layer of polymer (4,5).

2. Membrane according to the preceding claim, characterized in that the metal layer (3) is chosen from at least one of the following metals or alloys: aluminum, steel, in particular stainless steel.

3. Membrane according to the preceding claim, characterized in that the thickness of the metal layer (3) is between 20 pm and 200 pm, in particular between 50 and 150 pm.

4. Membrane according to one of the preceding claims, characterized in that at least one of the polymer layers (4, 5), in particular the two polymer layers, comprise at least one elastomer, in particular chosen from fluoroelastomers (FKM), perfluoroelastomers (FFKM), copolymers of butadiene-acrylonitrile type, hydrogenated or not (NBR or HNBR),

5. Membrane according to one of the preceding claims, characterized in that the thickness of at least one of the polymer layers (4, 5), in particular of the two polymer layers, is between 100 pm and 400 pm, in particular between 200 pm and 300 pm.

6. Membrane according to one of the preceding claims, characterized in that the total thickness of the metal layer (3) and of the two polymer layers (4, 5) is at most 8 mm, in particular at most 7 mm, and is preferably between 4 and 6 mm.

7. Membrane according to one of the preceding claims, characterized in that a means ensures adhesion between at least one of the polymer layers (4, 5) and the metal layer (3), in particular in the form of an adhesive.

8. Membrane according to one of the preceding claims, characterized in that it comprises at least one metal insert (11) arranged in an orifice of said cylindrical sleeve (2) for connection to a measuring system.

9. Membrane according to the preceding claim, characterized in that said insert (11) comprises clamping means (7, 8) for a portion of said cylindrical sleeve (2), a retaining means (9) for said clamping means (7, 8), and a hollow rod (10) for connection with a measuring system, said hollow rod passing through said cylindrical sleeve (2) and being fixed on said clamping means (7, 8).

10. Method of manufacturing the membrane according to one of the preceding claims, characterized in that: - a first cylindrical sleeve is produced with the first layer of polymer (4), - this first sleeve is covered with a metal sheet to produce the metal layer (3) - polymer is deposited, in particular by extrusion, on the metal layer (3) to produce the second layer of polymer (5).

11. Method for analyzing the flow of a fluid in a porous medium, characterized in that the following steps are implemented: a. Said porous medium (6) is inserted into the membrane (1) according to one of claims 8 or 9, b. Said at least one insert (11) of said membrane (1) is connected to a measuring installation, and c. A fluid is circulated in said porous medium (6), and d. A measurement is carried out by means of said measuring installation during said circulation of said fluid.

12. An analysis method according to claim 11, wherein said porous medium is a rock, said fluid is a fluid injected or present in an underground formation, and the measuring step involves measuring the pressure and / or temperature at said insert of said membrane.

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