Sample holder for measuring the permeablity of a sample during shear deformation, and associated measuring device and method

Abstract

Sample holder for measuring the permeablity of a sample during shear deformation, and associated measuring device and method The invention relates to a sample holder (12) for measuring the permeability during shear deformation of a sample of material consisting of rock powders. The sample holder (12) comprises a central block (28) and at least one, preferably two, lateral block(s) (30, 32), the central block (28) having at least one central interface (34, 36), the or each lateral block (30, 32) having a lateral interface (60, 62). The central block (28) and the at least one lateral block (30, 32) are adapted to receive a sample layer (84, 86) of the sample between the central block (28) and the or each lateral block (30, 32), the sample layer (84, 86) coupling with the central interface (34, 36) on a first side and with the lateral interface (60, 62) on a second side. The invention further relates to a corresponding measuring device and method.

Description

[0001] Sample holder for measuring the permeablity of a sample during shear deformation, and associated measuring device and method

[0002] The present invention relates to a sample holder, a device and a method for measuring the permeability during shear deformation of a sample of material consisting of rock powders, in particular a sample of fault gouge.

[0003] This enables measuring the permeability of materials, such as gouge contained within a tectonic fault during simulated fault slip experiments.

[0004] This can be useful in studies for underground storage, for example of radioactive waste or CO2, where it is interesting to study the evolution of permeability depending on different conditions, such as shear force or slip rate, and in different directions with respect to the direction of fault slip. If the results of such a study are inaccurate, this may have dramatic consequences in future projects based on said results.

[0005] CN 1 12362558 A describes a device for testing the permeability of a parallelepipedal sample along two perpendicular directions. This allows having information in regard to the parallelepipedal sample, as is.

[0006] However, in said device, the parallelepipedal sample is maintained and no particular conditions are applied apart from the oil confining the sample, the water injected into the parallelepipedal sample through passages, and shear deformation.

[0007] The object of the invention is thus to propose a sample holder allowing to measure the permeability of a sample of material under different conditions during simulated fault slip.

[0008] To that end, the invention relates to a sample holder for measuring the permeability during shear deformation of a sample of material consisting of rock powders, the sample holder comprising a central block and at least one, preferably two, lateral block(s), the central block having at least one central interface, the or each central interface having an upper hydraulic port and a lower hydraulic port spaced from one another along a longitudinal central direction, the or each lateral block having a lateral interface, the or each lateral interface having an upper hydraulic port and a lower hydraulic port spaced from one another along a longitudinal lateral direction, the central block and the at least one lateral block being adapted to receive a sample layer of the sample between the central block and the or each lateral block, the sample layer coupling with the central interface on a first side and with the lateral interface on a second side, such that the longitudinal central direction and the longitudinal lateral direction are parallel and the second side is opposite the first side along a transverse direction perpendicular to the longitudinal central direction. Having an upper hydraulic port and a lower hydraulic port on each interface allows for measuring the permeability along different paths through the sample layer, and thus along different directions. Furthermore, having a sample holder where the sample layer is arranged between two blocks allows acting on the environmental conditions on each block, for example to produce shear stress and / or displacement.

[0009] According to specific embodiments of the invention, the sample holder also has one or more of the following features, considered alone or according to any technically possible combination(s):

[0010] - each hydraulic port is adapted to be selectively connected to at least one fluidic line;

[0011] - each hydraulic port is fluidically connected to a respective connector adapted to be connected to a fluidic line;

[0012] - the central block and the at least one lateral block are mobile relative to each other, in particular in a translation in a direction parallel to the longitudinal central direction;

[0013] - the central block and the at least one lateral block are mobile relative to each other between an initial configuration and a final configuration, the central block being moved relative to the at least one lateral block of a maximal distance between the initial configuration and the final configuration, the maximal distance being preferably comprised between 12 mm and 16 mm;

[0014] - in the initial configuration, the lower hydraulic port of the central interface faces the lower hydraulic port of the lateral interface along the transverse direction and / or, in the final configuration, the upper hydraulic port of the central interface faces the upper hydraulic port of the lateral interface along the transverse direction;

[0015] - the difference of the distance measured along the longitudinal central direction between the upper hydraulic port and the lower hydraulic port of the central block and the distance measured along the longitudinal lateral direction between the upper hydraulic port and the lower hydraulic port of the lateral block is equal to the maximal distance with a tolerance, for example of + / - 2 mm; and / or

[0016] - the sample holder comprises two lateral blocks, the central block comprising two central interfaces arranged on opposite sides of the central block, each lateral block facing a respective central interface.

[0017] The invention further relates to a measuring device for measuring the permeability of a sample of material consisting of rock powders, the measuring device comprising a sample holder as described previously, the measuring device further comprising at least two fluidic lines, each fluidic line being connectable to at least one of the hydraulic ports of the sample holder. According to specific embodiments of the invention, the measuring device also has one or more of the following features, considered alone or according to any technically possible combination(s):

[0018] - each fluidic line is selectively connectable to only one hydraulic port at a time;

[0019] - each fluidic line is selectively connectable to different hydraulic ports, such that, for each pair of hydraulic ports, a first of the fluidic lines is connectable to a first hydraulic port of the pair and a second of the fluidic lines is connectable to the second hydraulic port of the pair;

[0020] - a first of the fluidic lines is selectively connectible to the upper hydraulic port and the lower hydraulic port of the central block and one of the hydraulic ports of the lateral block, a second of the fluidic lines being selectively connectable to the upper hydraulic port and the lower hydraulic port of said lateral block;

[0021] - the measuring device comprises two horizontal pistons, the horizontal pistons being arranged on each side of the sample holder along the transverse direction, each horizontal piston being adapted to apply a normal force along the transverse direction, such that the normal forces press the sample holder; and / or

[0022] - the measuring device comprises a vertical piston, the vertical piston being adapted to apply a shear force on the central block, the shear force being along the longitudinal central direction.

[0023] The invention further relates to a method for measuring the permeability of a sample of material consisting of rock powders, comprising the following steps:

[0024] - providing a measuring device as described previously,

[0025] - arranging a sample layer of the sample between the central block and the or each lateral block, the sample layer cooperating with the central interface on a first side and with the lateral interface on a second side, the second side being opposite the first side along a transverse direction perpendicular to the longitudinal central direction,

[0026] - fluidically connecting each fluidic line to a different hydraulic port,

[0027] - injecting fluid into one of the fluidic lines, and

[0028] - measuring fluid withdrawn in the other of the fluidic lines.

[0029] Other features and advantages of the invention will appear upon reading the following description, provided solely as an example and done in reference to the appended drawings, in which:

[0030] - figure 1 is a schematic representation of a measuring device according to an example of the invention, in a first fluidic configuration,

[0031] - figures 2 to 6 are partial schematic sectional representations of the measuring device of figure 1 , in other different fluidic configurations, - figure 7 is a front view and sectional views along planes A-A and B-B of a central block of a sample holder according to an example of the invention, and

[0032] - figure 8 is a front view of a lateral block of a sample holder according to an example of the invention.

[0033] In the following description, the terms “upper” and “lower” are used in regard to longitudinal directions X1 , X2. Said longitudinal directions do not necessarily correspond to the vertical direction defined as the perpendicular to the floor or in relation to gravity. Similarly, “vertical” and “horizontal” are used in regard to longitudinal directions X1 , X2.

[0034] A measuring device 10 according to an example of the invention is schematically represented on figure 1 and partially schematically represented on figures 2 to 6.

[0035] The measuring device 10 is adapted to measure the permeability during shear deformation of a sample of material consisting of rock powders, in particular a sample of fault gouge.

[0036] The measuring device 10 comprises a sample holder 12, and fluidic lines 14, 16.

[0037] The measuring device 10, for example, further comprises two horizontal pistons 18, 20 and / or a vertical piston 22.

[0038] The measuring device 10, for example, comprises a pressure vessel 24 and a sleeve 26.

[0039] The sample holder 12 comprises a central block 28 and at least one lateral block 30, 32.

[0040] An example of a central block 28 is represented on figure 7.

[0041] The central block 28 has at least one central interface 34, 36.

[0042] Here, the central block 28 comprises two central interfaces arranged on opposite sides of the central block 28, in particular opposite along a transverse direction Y.

[0043] Each central interface 34, 36 here extends in a plane, for example here perpendicular to the transverse direction Y.

[0044] Each central interface 34, 36 has an upper hydraulic port 38, 40 and a lower hydraulic port 42, 44 spaced from one another along a longitudinal central direction X1 .

[0045] Each hydraulic port is adapted to be selectively connected to at least one fluidic line.

[0046] Here, each hydraulic port is fluidically connected to a respective connector 46, 48, 50, 52 adapted to be connected to a fluidic line.

[0047] Each hydraulic port comprises a porous area 54, where at least one, here one, respective fluidic opening 56 opens out.

[0048] The porous area 54 is, for example, made of porous frits.

[0049] The porous area 54 is, for example, made of steel. The porous area 54 principally extends in a main direction, perpendicular to the longitudinal central direction X1 , and here also perpendicular to the transverse direction Y.

[0050] Each porous area 54, for example, has an oblong shape.

[0051] The hydraulic ports have the same shapes and dimensions.

[0052] Here, each porous area 54 is, optionally, provided with at least one hole, here at one of its extremities. Said hole, for example, comprises a thread.

[0053] This enables attaching an additional steel plate to said porous area 54 with screws.

[0054] The additional steel plate is, for example, provided with teeth on the side that is not facing the block, the gouge layer being placed against said side.

[0055] The porous area is, for example, attached on top of the additional steel plate.

[0056] The additional steel plate is, for example, advantageous to fill the potential space due to grooves on the blocks.

[0057] The teeth strengthen the coupling between the block and the gouge layer and force the deformation within the gouge layer.

[0058] Each respective fluidic opening 56 is fluidically connected to the respective connector, in particular by a fluid passage 58 delimited inside the central block 28.

[0059] The upper hydraulic ports 38, 40 of the two central interfaces 34, 36 are, for example, arranged at the same height measured along the longitudinal central direction X1 .

[0060] The lower hydraulic ports 42, 44 of the two central interfaces 34, 36 are, for example, arranged at the same height measured along the longitudinal central direction X1 .

[0061] The porous areas of the upper hydraulic ports 38, 40 and the lower hydraulic ports 42, 44 of the two central interfaces 34, 36 are, for example, symmetrical in regard to a median plane of the central block, said median plane extending perpendicular to the transverse direction Y.

[0062] For each central interface 34, 36, the respective fluidic openings of the upper hydraulic port and the lower hydraulic port are offset along the direction perpendicular to the longitudinal central direction X1 and the transverse direction Y.

[0063] The upper hydraulic port 38 of a first central interface 34 and the lower hydraulic port 44 of the second central interface 36 are, on the same plane A-A, said plane extending along the longitudinal central direction X1 and the transverse direction Y.

[0064] The corresponding respective fluid passages and respective connectors, for example, also extend along said plane A-A.

[0065] The lower hydraulic port 42 of the first central interface 34 and the upper hydraulic port 40 of the second central interface 36 are, on the same plane B-B, said plane extending along the longitudinal central direction X1 and the transverse direction Y. The corresponding respective fluid passages and respective connectors, for example, also extend along said plane B-B.

[0066] An example of a lateral block is represented on figure 8.

[0067] Here, the sample holder 12 comprises at least two, here two, lateral blocks 30, 32, each lateral block 30, 32 facing a respective central interface 36, 34.

[0068] The or each lateral block 30, 32 has a lateral interface 60, 62, facing a corresponding central interface.

[0069] The or each lateral interface 30, 32 has an upper hydraulic port 64, 66 and a lower hydraulic port 68, 70 spaced from one another along a longitudinal lateral direction X2.

[0070] The longitudinal lateral direction X2 is here parallel to the longitudinal central direction X1 .

[0071] Each hydraulic port 64, 66, 68, 70 is adapted to be selectively connected to at least one fluidic line.

[0072] Here, each hydraulic port 64, 66, 68, 70 is fluidically connected to a respective connector 74, 76, 72, 78 adapted to be connected to a fluidic line.

[0073] Each hydraulic port comprises a porous area 80, where at least one, here one, respective fluidic opening 82 opens out.

[0074] The porous area 80 is, for example, made of porous frits.

[0075] The porous area 80 is, for example, made of steel.

[0076] The porous area 80 principally extends in a main direction, perpendicular to the longitudinal lateral direction X2, and here also perpendicular to the transverse direction Y.

[0077] Each porous area 80, for example, has an oblong shape.

[0078] The hydraulic ports have the same shapes and dimensions with the hydraulic ports of the central block.

[0079] Here, each porous area 80 is, optionally, provided with at least one hole, here at one of its extremity. Said hole, for example, comprises a thread. This enables attaching an additional steel plate to said porous area 80 with screws.

[0080] The additional steel plate is, for example, provided with teeth on the side that is not facing the block, the gouge layer being placed against said side.

[0081] The porous area is, for example, attached on top of the additional steel plate.

[0082] The additional steel plate is, for example, advantageous to fill the potential space due to grooves on the blocks.

[0083] The teeth strengthen the coupling between the block and the gouge layer and force the deformation within the gouge layer. Moreover, the additional steel plate allows positioning a piezoelectric sensor to measure ultrasonic wave speeds during experiments, if wanted, on the lateral block, on the side facing said lateral block.

[0084] Each respective fluidic opening 82 is fluidically connected to the respective connector, in particular by a fluid passage delimited inside the lateral block.

[0085] The or each lateral block 30, 32 is, for example, provided with a central hole, for example arranged in the center of the lateral interface 60, 62. The central hole is here adapted to receive an optional additional sensor, for example a piezoelectric sensor.

[0086] The upper hydraulic ports 64, 66 of the two lateral interfaces 60, 62 are, for example, arranged at the same height measured along the longitudinal lateral direction X2.

[0087] The lower hydraulic ports 68, 70 of the two lateral interfaces 60, 62 are, for example, arranged at the same height measured along the longitudinal lateral direction X2.

[0088] The porous areas of the upper hydraulic ports 64, 66 and the lower hydraulic ports 68, 70 of the two lateral interfaces 60, 62 are, for example, symmetrical in regard to a median plane of the central block, said median plane extending perpendicular to the transverse direction Y.

[0089] For each lateral interface 60, 62, the respective fluidic openings of the upper hydraulic port and the lower hydraulic port are offset along the direction perpendicular to the longitudinal lateral direction X2 and the transverse direction Y.

[0090] The central block 28 and the each lateral block 30, 32 are adapted to receive a sample layer 84, 86 of the sample between the central block 28 and each lateral block 30, 32.

[0091] The sample layer is made of sample of material consisting of rock powders, in particular a sample of fault gouge.

[0092] The or each sample layer 84, 86 cooperates with the central interface 34, 36 on a first side and with the lateral interface 60, 62 on a second side. The second side is opposite the first side along a direction perpendicular to the longitudinal central direction, here the transverse direction Y.

[0093] When there are two lateral blocks, each sample layer is arranged between a central interface and a lateral interface facing each other, later called pair of interfaces facing each other.

[0094] The central block 28 and each lateral block 30, 32 are mobile relative to each other, in particular in translation in a direction parallel to the longitudinal central direction X1 .

[0095] More precisely, in the measuring device, the two lateral blocks 30, 32 are immobile in regard to the pressure vessel 24 along the longitudinal central direction X1 , while the central block 28 is mobile in translation along the longitudinal central direction X1 . Thus, the central block 28 is a sliding block.

[0096] The central block 28 is mobile in translation in a direction going from the upper hydraulic port 38, 40 to the lower hydraulic port 42, 44.

[0097] The central block 28 and each lateral block 30, 32 are mobile relative to each other between an initial configuration, depicted on figures 1 and 2, and a final configuration, depicted on figures 5 and 6.

[0098] The central block 28 and each lateral block 30, 32 are, for example, mobile relative to each other in at least one intermediate configuration, as depicted on figure 3, between the initial configuration and the final configuration.

[0099] The central block 28 is moved relative to each lateral block 30, 32 of a maximal distance between the initial configuration and the final configuration.

[0100] The maximal distance is such as to align the lower hydraulic ports 42, 44, 70, 68 in the initial configuration, and the upper hydraulic ports 38, 40, 66, 64 in the final configuration, as will be discussed below.

[0101] The maximal distance is preferably comprised between 12 mm and 16 mm.

[0102] In the initial configuration, each sample layer 84, 86 covers the surface of each interface of the corresponding pair of interfaces strictly in regard to one another along the transverse direction Y, and only said surface.

[0103] In the initial configuration, the lower hydraulic port 42, 44 of the central interface 34, 36 face, along the transverse direction Y, the lower hydraulic port 70, 68 of the lateral interface 62, 60 facing said central interface 34, 36.

[0104] In the final configuration, the sample layer 84, 86 covers the surface of each interface of the corresponding pair of interfaces in regard to one another along the transverse direction Y and the surface of each interface covered in the initial configuration, and only said surfaces.

[0105] Moreover, here, in the final configuration, the upper hydraulic port 38, 40 of the central interface 34, 36 face, along the transverse direction Y, the upper hydraulic port 66, 64 of the lateral interface 62, 60 facing said central interface 34, 36.

[0106] The upper hydraulic ports of a pair of interfaces facing each other are always above the lower hydraulic ports of said pair of interfaces along the longitudinal directions X1 , X2.

[0107] The difference of the distance measured along the longitudinal central direction X1 between the upper hydraulic port 38, 40 and the lower hydraulic port 42, 44 of the central block 28 and the distance measured along the longitudinal lateral direction X2 between the upper hydraulic port 64, 66 and the lower hydraulic port 68, 70 of the lateral block 30, 32 is equal to the maximal distance, with a given tolerance, for example of + / - 2 mm. The distance between an upper hydraulic port and a lower hydraulic port of a given interface along the corresponding longitudinal direction is measured between the median axis of said ports along said longitudinal direction.

[0108] The measuring device 10 comprises at least two fluidic lines 14, 16, more particularly two fluidic lines 14, 16 per lateral block 30, 32.

[0109] Each fluidic line 14, 16 is a passageway for a fluid, for example water, nitrogen or argon gas.

[0110] Each fluid line 14, 16 is here connected to a fluid source.

[0111] Each fluidic line 14, 16 of a lateral interface is, for example, connected to a distinct respective fluid source.

[0112] Here, each fluid source is connected to a plurality of, here two, fluidic lines, one fluidic line of each interface of a pair of facing lateral interface-central interface.

[0113] More particularly, the fluidic lines sharing a fluid source are connected to symmetric porous areas, via similar passageways.

[0114] Alternatively, some or the fluidic lines share a fluid source. For example, all the fluidic lines share a fluid source, each fluidic line being connected to the fluid source through a valve.

[0115] Each fluidic line 14, 16 is connectable to at least one of the hydraulic ports 38, 40, 42, 44, 64, 66, 68, 70 of the sample holder 12, more particularly via the corresponding connector.

[0116] Each fluidic line 14, 16 is selectively connectable to only one hydraulic port 38, 40, 42, 44, 64, 66, 68, 70 at a time, in particular via a valve system.

[0117] Each fluidic line 14, 16 is, for example, selectively connectable to different hydraulic ports 38, 40, 42, 44, 64, 66, 68, 70, such that, for each pair of hydraulic ports 38, 40, 42, 44, 64, 66, 68, 70 of a given interface or of facing interfaces, a first of the fluidic lines is connectable to a first hydraulic port of the pair and a second of the fluidic lines is connectable to the second hydraulic port of the pair.

[0118] Here, the first line 16 is a supply line, supplying fluid towards the sample holder, while the second line 14 is a withdrawal line, withdrawing fluid from the sample holder.

[0119] This enables that every possible fluidic path through each sample layer may be induced.

[0120] For each pair of interfaces facing each other, a first 16 of the fluidic lines is selectively connectible to the upper hydraulic port 38 and the lower hydraulic port 42 of the central block 28 and one 66 of the hydraulic ports of the lateral block 30, here the upper hydraulic port of the lateral block, a second 14 of the fluidic lines being selectively connectable to the upper hydraulic port 66 and the lower hydraulic port 70 of said lateral block 30. This enables that every possible fluidic path through each sample layer may be induced.

[0121] Here, the device, for each pair of interfaces facing each other, comprises a first three-way valve 88 with three ways, a two-way valve 90 with two ways, and a second three- way valve 92 with three ways.

[0122] Each three-way valve is adapted to selectively connect one of its ways to one and only one of its other ways, or here additionally close the passageway.

[0123] The two-way valve is adapted to selectively connect its two ways or to close the passageway.

[0124] The three ways of the first three-way valve 88 are respectively fluidically connected to the upper hydraulic port 38 of the central interface 34, the lower hydraulic port 42 of the central interface 34 and the first line 16.

[0125] The two ways of the two-way valve 90 are respectively fluidically connected to the second line 14 and the lower hydraulic port 70 of the lateral interface 62.

[0126] The three ways of the second three-way valve 92 are respectively fluidically connected to the second line 14, the first line 16, and the upper hydraulic port 66 of the lateral interface 62.

[0127] Such an arrangement enables that every possible fluidic path through each sample layer may be induced.

[0128] Moreover, the second line 14 may be disconnected from the hydraulic port 66 and the first line 16, by closing the second three-way valve 92.

[0129] The horizontal pistons 18, 20 are arranged on each side of the sample holder 18 along the transverse direction Y.

[0130] More precisely, each horizontal piston 18, 20 is arranged against a respective lateral block 30, 32 on the opposite side relative to the lateral interface along the transverse direction Y.

[0131] Each horizontal piston 18, 20 is adapted to apply a normal force o along the transverse direction Y, such that the normal forces press the sample holder 28.

[0132] The normal forces o applied by the horizontal pistons 18, 20 are opposed to each other. Their absolute value is equal.

[0133] The vertical piston 22 is adapted to apply a shear force u on the central block 28, the shear force u being applied along the longitudinal central direction X1 .

[0134] The application of the shear force u results from the translation of the central block 28 along the longitudinal central direction X1 .

[0135] The application of the shear deformation induces shear force within the sample layer that are arranged between the interfaces. The vertical piston 22 is adapted to apply the translation of the central block 28 moves, in regard to the lateral block(s) 30, 32, from the initial configuration to the final configuration.

[0136] The vertical piston 22 lies against an upper surface 94 of the central block 28, such an upper surface 94 being perpendicular to the longitudinal central direction X1 .

[0137] The upper surface 94 here forms an extremity of the central block along the longitudinal central direction X1 .

[0138] The upper surface 94 is closer to the upper hydraulic ports 38, 40 than to the lower hydraulic ports 42, 44.

[0139] The sample holder 12, and here the horizontal pistons 18, 20 and the vertical piston 22, are arranged within the pressure vessel 24.

[0140] The pressure vessel 24 defines a confinement volume 96, the sample holder 12, and here the horizontal pistons 18, 20 and the vertical piston 22, being within the confinement volume 96.

[0141] The confinement volume 96 can be hermetically sealed.

[0142] The pressure within the pressure vessel 24 is, controlled, for example using hydraulic servo-controlled intensifiers.

[0143] The confinement volume 96, for example, contains a pressure fluid.

[0144] The pressure of the pressure vessel is controllable through the pressure of the pressure fluid.

[0145] The sleeve 26 partially surrounds the central block 28 and each lateral block 30, 32.

[0146] The sleeve 26 fluidly isolates the interfaces, and the sample layer(s) arranged on the interfaces, from the pressure fluid in the confinement volume 96.

[0147] Different fluidic configurations are represented on figures 1 to 6.

[0148] For figures 2 to 6, only a central interface and a lateral interface facing each other are shown. However, this may be applied on both pairs of interfaces facing each other.

[0149] The same fluidic configuration or different fluidic configurations may be operated on the pairs of interfaces facing each other simultaneously.

[0150] The fluidic configurations will be described more in details in regard to the measuring method described now.

[0151] In an embodiment, the measuring device only has one lateral block.

[0152] The central block, for example, only has one central interface, facing the lateral block.

[0153] On the other side of the central block relative to the central interface, is, for example, provided a frictionless surface to allow the sliding of the central block without influencing the measurements. The measuring method for measuring the permeability of a sample of material consisting of rock powders, in particular a sample of fault gouge, of the invention will be described in regard to figures 1 to 6.

[0154] The method comprises the following steps:

[0155] - providing a measuring device as previously described,

[0156] - arranging a sample layer 84, 86 of the sample between the central block 28 and each lateral block 30, 32, the sample layer 84, 86 cooperating with the central interface 34, 36 on a first side and with the lateral interface 62, 64 on a second side, the second side being opposite the first side along the transverse direction Y,

[0157] - fluidically connecting each fluidic line 14, 16 to a different hydraulic port,

[0158] - injecting fluid into one 14 of the fluidic lines, called supply line, and

[0159] - measuring fluid withdrawn in the other 16 of the fluidic lines, called withdrawal line.

[0160] During the step of arranging, the sample layer is fixedly connected to the central interface on the first side and to the lateral interface on the second side.

[0161] The sample layer 84, 86 is arranged such as to cover the surface of each interface of the corresponding pair of interfaces strictly in regard to one another along the transverse direction Y, and only said surface.

[0162] During the arranging step, the blocks are in the initial configuration.

[0163] The steps of fluidically connecting, injecting fluid and measuring fluid are done after the steps of providing and arranging a sample layer.

[0164] During the steps of fluidically connecting, for each pair of interfaces facing each other, two different hydraulic ports of said pair of interfaces are connected to a different fluidic line 14, 16.

[0165] Each fluidic line 14, 16 is selectively connected to only one port.

[0166] In the rest of the description of the method, only one pair of interfaces facing each other will be considered. For the simplicity of the explanation, this will not be repeated each time.

[0167] The steps of injecting fluid and measuring fluid are done while the fluidic lines are connected.

[0168] The measuring of the fluid withdrawn in line 16 is done in parallel to the injecting of fluid into line 14.

[0169] During the steps of injecting fluid and measuring fluid, opposite normal forces o are, for example, applied.

[0170] During the steps of injecting fluid and measuring fluid, a controlled pressure is, for example, applied inside the confinement volume 96. The two connected hydraulic ports are connected by a fluidic path defined through the sample layer 84, 86.

[0171] The amount of fluid passing through said fluidic path depends on the permeability of the sample material along said fluidic path.

[0172] The amount of fluid that travels from the port connected to the supply line 14 to the port connected to the withdrawal line 16 for a given pressure of the fluid injected into the supply line 14 and a given pressure of the fluid withdrawn in the withdrawal line 14 depends on the permeability of the sample material along said fluidic path.

[0173] Thus, by measuring the fluid that reaches the port connected to the withdrawal line 16, and thus the fluid running through the withdrawal line 16, one may measure the permeability of the sample material along the fluidic path.

[0174] The different possible fluidic configurations allow calculating the permeability of the sample material along different fluidic paths, and thus along different directions of the sample material with respect to the direction of fault slip.

[0175] Furthermore, a shear force u may be applied, such that the impact of said force on the permeability may be studied.

[0176] The steps of fluidically connecting, injecting fluid and measuring fluid are, for example, reiterated, in particular for different conditions, for examples for different fluidic connections and / or for different shear forces u.

[0177] For each iteration, different ports are, for example, connected to the fluidic lines 14, 16.

[0178] The method, for example, comprises at least one iteration where the lower hydraulic ports are each connected to a fluidic lines 14, 16 or the upper hydraulic ports are each connected to a fluidic lines 14, 16 and at least one iteration where a lower hydraulic port is connected to a fluidic line and an upper hydraulic port is connected to the other fluidic line.

[0179] This enables measuring the permeability in two directions.

[0180] Here, the method, for example, comprises at least one iteration where the lower hydraulic ports are each connected to a fluidic lines 14, 16 where the blocks are in the initial configuration, one iteration where the upper hydraulic ports are each connected to a fluidic lines 14, 16 where the blocks are in the final configuration, one iteration where a lower hydraulic port is connected to a fluidic line and an upper hydraulic port is connected to the other fluidic line when the blocks are in the initial configuration, and one iteration where a lower hydraulic port is connected to a fluidic line and an upper hydraulic port is connected to the other fluidic line when the blocs are in the final configuration.

[0181] The iterations in the initial configuration are done before the iterations in the final configuration. This enables measuring the permeability in two directions without and with the application of shear force u, and thus a shear stress within the sample material.

[0182] The method here comprises an iteration where the blocks are in the initial configuration and the lower hydraulic port 42 of the central interface 34 is connected to a line 16, here the supply line 16, and the upper hydraulic port 66 of the lateral interface 62 is connected to the other line 14, here the withdrawal line, as depicted on figure 1 .

[0183] No shear force is applied here by the vertical piston 22.

[0184] The permeability of the sample layer 86 along the longitudinal direction with no shear force is here measured.

[0185] The method here comprises an iteration where the blocks are in the initial configuration and the lower hydraulic ports 42, 70 are each connected to a line 14, 16.

[0186] Here, the lower hydraulic port 42 of the central interface 34 is connected to a line, here the supply line 16, and the lower hydraulic port 70 of the lateral interface 62 is connected to the other line 14, here the withdrawal line, as depicted on figure 2.

[0187] No shear force is applied here by the vertical piston 22.

[0188] The permeability of the sample layer 86 along the transverse direction with no shear force is here measured.

[0189] The method further here comprises an iteration where the blocks are in an intermediate configuration and the lower hydraulic port 42 of the central interface 34 is connected to a line 16, here the supply line 16, and the upper hydraulic port 66 of the lateral interface 62 is connected to the other line 14, here the withdrawal line, as depicted on figure 3.

[0190] Any shear force is applied here by the vertical piston 22.

[0191] The permeability of the sample layer 86 along the longitudinal direction with any shear force is here measured.

[0192] The method further here comprises an iteration where the blocks are in any configuration and the upper hydraulic port 66 of the lateral interface 62 is connected to a line 16, here the supply line 16, and the lower hydraulic port 70 of the lateral interface 62 is connected to the other line 14, here the withdrawal line, as depicted on figure 4.

[0193] Any shear force may be applied here by the vertical piston 22.

[0194] The permeability of the sample layer 86 along the longitudinal direction with any shear force is here measured.

[0195] The method here comprises an iteration where the blocks are in the final configuration and the upper hydraulic port 38 of the central interface 34 is connected to a line 16, here the supply line 16, and the lower hydraulic port 70 of the lateral interface 62 is connected to the other line 14, here the withdrawal line, as depicted on figure 5. Any shear force is applied here by the vertical piston 22.

[0196] The permeability of the sample layer 86 along the longitudinal direction with any shear force is here measured.

[0197] The method here comprises an iteration where the blocks are in the final configuration and the upper hydraulic ports 38, 66 are each connected to a line 14, 16.

[0198] Here, the upper hydraulic port 38 of the central interface 34 is connected to a line, here the supply line 16, and the upper hydraulic port 66 of the lateral interface 62 is connected to the other line 14, here the withdrawal line, as depicted on figure 6.

[0199] Any shear force is applied here by the vertical piston 22.

[0200] The permeability of the sample layer 86 along the transverse direction with any shear force is here measured.

[0201] The method, for example, comprises the iterations described in regard to figures 1 , 2, 5 and 6, or the iterations described in regard to figures 1 , 2, 4 with the final configuration of blocks and 6, or the iterations described in regard to figures 4 with the initial configuration of blocks, 2, 4 with the final configuration of blocks and 6, or the iterations described in regard to figures 4 with the initial configuration of blocks, 2, 5 and 6.

[0202] This enables measuring the permeability in the transverse direction and the longitudinal direction with and without the application of shear force TJ.

[0203] Additionally, the method, for example, further comprises the iterations described in regard to figures 4 and 5 with the intermediate configuration.

[0204] This enables measuring the permeability in the longitudinal direction with the intermediate configuration.

[0205] The iterations are done with an increasing shear deformation or “fault slip”.

[0206] Thus, after the arranging step, the first iteration(s) are done in the initial configuration of the blocks, and then, if so, later iteration(s) are done in an intermediate configuration or in intermediate configurations going from the initial configuration to the final configuration, and lastly, the last iteration(s) are done in the final configuration of the blocks.

[0207] Thus, the sample holder, the measuring device and the measuring method allow measuring the permeability of a sample material along different directions, and with different shear deformation.

Claims

CLAIMS1. Sample holder (12) for measuring the permeability during shear deformation of a sample of material consisting of rock powders, the sample holder (12) comprising a central block (28) and at least one, preferably two, lateral block(s) (30, 32), the central block (28) having at least one central interface (34, 36), the or each central interface (34, 36) having an upper hydraulic port (38, 40) and a lower hydraulic port (42, 44) spaced from one another along a longitudinal central direction (X1 ), the or each lateral block (30, 32) having a lateral interface (60, 62), the or each lateral interface (60, 62) having an upper hydraulic port (64, 66) and a lower hydraulic port (68, 70) spaced from one another along a longitudinal lateral direction (X2), the central block (28) and the at least one lateral block (30, 32) being adapted to receive a sample layer (84, 86) of the sample between the central block (28) and the or each lateral block (30, 32), the sample layer (84, 86) coupling with the central interface (34, 36) on a first side and with the lateral interface (60, 62) on a second side, such that the longitudinal central direction (X1 ) and the longitudinal lateral direction (X2) are parallel and the second side is opposite the first side along a transverse direction (Y) perpendicular to the longitudinal central direction (X1 ).

2. Sample holder according to claim 1 , wherein each hydraulic port (38, 40, 42, 44, 64, 66, 68, 70) is adapted to be selectively connected to at least one fluidic line (14, 16).

3. Sample holder according to claim 1 or 2, wherein each hydraulic port (38, 40, 42, 44, 64, 66, 68, 70) is fluidically connected to a respective connector (46, 48, 50, 52, 72, 74, 76, 78) adapted to be connected to a fluidic line (14, 16).

4. Sample holder according to any one of claims 1 to 3, wherein the central block (28) and the at least one lateral block (30, 32) are mobile relative to each other, in particular in a translation in a direction parallel to the longitudinal central direction (X1 ).

5. Sample holder according to claim 4, wherein the central block (28) and the at least one lateral block (30, 32) are mobile relative to each other between an initial configuration and a final configuration, the central block (28) being moved relative to the at least one lateral block (30, 32) of a maximal distancebetween the initial configuration and the final configuration, the maximal distance being preferably comprised between 12 mm and 16 mm.

6. Sample holder according to claim 5, wherein, in the initial configuration, the lower hydraulic port (42, 44) of the central interface (34, 36) faces the lower hydraulic port (70, 68) of the lateral interface (60, 62) along the transverse direction (Y), and / or, in the final configuration, the upper hydraulic port (38, 40) of the central interface (34, 36) faces the upper hydraulic port (66, 64) of the lateral interface (60, 62) along the transverse direction (Y).

7. Sample holder according to claim 5 or 6, wherein the difference of the distance measured along the longitudinal central direction (X1 ) between the upper hydraulic port (38, 40) and the lower hydraulic port (34, 36) of the central block (28) and the distance measured along the longitudinal lateral direction (X2) between the upper hydraulic port (64, 66) and the lower hydraulic port (68, 70) of the lateral block (30, 32) is equal to the maximal distance with a tolerance, for example of + / - 2 mm.

8. Sample holder according to any one of claims 1 to 7, comprising two lateral blocks (30, 32), the central block (28) comprising two central interfaces (34, 36) arranged on opposite sides of the central block (28), each lateral block (30, 32) facing a respective central interface (34, 36).

9. Measuring device (10) for measuring the permeability of a sample of material consisting of rock powders, the measuring device (10) comprising a sample holder (12) according to any one of claims 1 to 8, the measuring device (10) further comprising at least two fluidic lines (14, 16), each fluidic line (14, 16) being connectable to at least one of the hydraulic ports (38, 40, 42, 44, 64, 66, 68, 70) of the sample holder (12).

10. Measuring device according to claim 9, wherein each fluidic line (14, 16) is selectively connectable to only one hydraulic port (38, 40, 42, 44, 64, 66, 68, 70) at a time.

11. Measuring device according to claim 10, wherein each fluidic line (14, 16) is selectively connectable to different hydraulic ports (38, 40, 42, 44, 64, 66, 68, 70), such that, for each pair of hydraulic ports (38, 40, 42, 44, 64, 66, 68, 70), a first of the fluidic lines is connectable to a first hydraulic port of the pair and a second of the fluidic lines is connectable to the second hydraulic port of the pair.

12. Measuring device according to claim 10 or 1 1 , wherein a first (16) of the fluidic lines is selectively connectible to the upper hydraulic port (38, 40) andthe lower hydraulic port (42, 44) of the central block (28) and one of the hydraulic ports (64, 66) of the lateral block (30, 32), a second (14) of the fluidic lines being selectively connectable to the upper hydraulic port (64, 66) and the lower hydraulic port (68, 70) of said lateral block (30, 32).

13. Measuring device according to any one of claims 9 to 12, comprising two horizontal pistons (18, 20), the horizontal pistons (18, 20) being arranged on each side of the sample holder (12) along the transverse direction (Y), each horizontal piston (18, 20) being adapted to apply a normal force along the transverse direction (Y), such that the normal forces press the sample holder (12).

14. Measuring device according to any one of claims 9 to 13, comprising a vertical piston (22), the vertical piston (22) being adapted to apply a shear force on the central block (28), the shear force being along the longitudinal central direction (X1 ).

15. Method for measuring the permeability of a sample of material consisting of rock powders, comprising the following steps:- providing a measuring device (10) according to any one of claims 9 to 14,- arranging a sample layer (84, 86) of the sample between the central block (28) and the or each lateral block (30, 32), the sample layer (84, 86) cooperating with the central interface (30, 32) on a first side and with the lateral interface (60, 62) on a second side, the second side being opposite the first side along a transverse direction (Y) perpendicular to the longitudinal central direction (X1 ),- fluidically connecting each fluidic line (14, 16) to a different hydraulic port (38, 40, 42, 44, 64, 66, 68, 70),- injecting fluid into one (16) of the fluidic lines, and- measuring fluid withdrawn in the other (14) of the fluidic lines.

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