Sensing apparatus for soil testing

Abstract

A sensing apparatus (1) for geomaterial penetration testing, comprising: a probe (2) comprising a sensor unit (21) for soil analysis and a tip (22) for penetration in the soil (10); an uphole acquisition system (3); and a plurality of pushing rods (4) configured to be joined together end-to-end to push the probe (2) under a subsurface (11) of the soil, each of the pushing rods (4) comprising two terminal connectors (41, 42) and an electrical conductor (61) electrically linking together the two terminal connectors (41, 42), the plurality of pushing rods (4) being configured to be electrically joined end- to-end to one another by one of their respective two terminal connectors (41, 42) to form an electrical connection allowing transmission of data from the sensor unit (21) to the uphole acquisition system (3).

Description

DescriptionTitle: Sensing apparatus for soil testingTechnical Field

[0001] The present invention relates to the technical field of soil analysis using geomaterial penetration testing techniques, in particular using sensors pushed down underground.Background Art

[0002] The use of downhole sensors in geomaterial penetration testing, such as those in the “cone penetration test”, hereafter called “CPT”, can provide valuable information regarding the engineering characteristics of soil and tailings.

[0003] The sensors are typically integrated into a probe comprising a cone tip for penetration into the ground. The cone tip is pushed hydraulicly into the subsurface. Pushing rods are incrementally joined to the cone tip to advance penetration of the probe.

[0004] The sensors used in penetration testing can include load cells, pressure transducers, geophones, inclinometers, magnetometers, cameras, and other sensors. These various sensors are generally connected to an uphole acquisition system for collecting data during the down movement of the cone tip, thereby allowing capturing and analyzing soil characteristics. To this end, the probe may be pushed up to hundreds of meters downhole in the ground.

[0005] In order to transmit the collected data, the sensors housed in the probe need to be in electrical communication with the uphole acquisition system as the cone tip is pushed down. To that end, a cable runs through each (hollow) pushing rod - even before they are installed and pushed in the ground - to form an electrical connection between the probe and the uphole data acquisition system (DAS). This cable is appropriately introduced successively through each of the pushing rods. This operation is cumbersome and can only be done manually by an operator. Should the cable be damaged, the operation of introducing the cable through all the pushing rods must be repeated with a new cable. In addition, in the event of a pushing rod being damaged, the cable must be withdrawn from all the pushing rods. The current system is therefore cumbersome and not robust to any part of the system being damaged.

[0006] This document aims to present an improvement to penetration testing technologies that at least partly address these issues.Summary

[0007] The present disclosure relates to a sensing apparatus for geomaterial penetration testing, comprising: a probe comprising a sensor unit for soil analysis and a tip for penetration in the soil; an uphole acquisition system; and a plurality of pushing rods configured to be joined together end-to-end to push the probe under a subsurface of the soil, each of the pushing rods comprising two terminal connectors and an electrical conductor electrically linking together the two terminal connectors, the plurality of pushing rods being configured to be electrically joined end-to-end to one another by one of their respective two terminal connectors to form an electrical connection allowing transmission of data from the sensor unit to the uphole acquisition system.

[0008] This new system is void of a cable that runs through all the pushing rods before the pushing rods are installed and pushed in the ground, while still enabling reliable measurements. This solution is robust to a part being damaged, as a pushing rod can be replaced without the need to repeat the operation of passing a cable through all the pushing rods. The solution is versatile as a defective pushing rod can be immediately and easily replaced with another equivalent pushing rod, without the need to withdraw the cable from all the pushing rods. Indeed, each pushing rod constitutes a segment of the electrical connection. The damaged segment may be replaced, and the connection may be reestablished easily with minimized time and effort.

[0009] In addition, the risk of damaging the cable while handling the pushing rods is prevented. The solution hereby disclosed also reduces the time and effort required for using the sensing apparatus.

[0010] By eliminating the need for a cable to be strung through the pushing rods, the system enhances efficiency and facilitates the potential for automating and / or robotizing cone penetration testing operations, further streamlining the overall process.

[0011] Furthermore, the sensing apparatus hereby disclosed may be implemented in existing installations, in particular existing pushing rods, thus minimizing the cost to be invested for retrofitting existing material.

[0012] The features set out in the following paragraphs can optionally be implemented, independently from one another or in combination with one another.

[0013] In some examples, the sensing apparatus comprises a multiplexing communication system connecting the sensing unit to the uphole acquisition system, the multiplexing communication system comprising a downhole adapter multiplexing data acquired from the sensing unit, an uphole adapter de-multiplexing data to feed to the uphole acquisition system, and the electrical connectionconnecting the uphole adapter to the downhole adapter. This is beneficial for the simplicity of the construction of the pushing rods as they do not require their electric conductor to be complex.

[0014] In some examples, the electrical connection is further configured to feed power to the sensor unit. In particular examples, data and power are transmitted via a single electrical conductor. This design allows for a compact, lightweight pushing rod with a combined function of feeding current downwards and retrieving data upwards.

[0015] In some examples, the electrical conductor is a BNC coaxial cable. Such a cable ensures reliable and high-quality data transmission over long distances, which is particularly adapted for cone penetration tests.

[0016] In some examples, the two terminal connectors comprise a first terminal connector and a second terminal connector, wherein the first terminal connector is a female connector, and the second terminal connector is a male connector. This arrangement allows to produce similar pushing rods while ensuring a mechanical coding (“poka-yoke” or error-proof system).

[0017] In some examples, each pushing rod comprises an outer cylinder and an inner transmission rod housed inside the outer cylinder, and the electrical conductor comprises a cable contained inside said inner transmission rod. The outer cylinder may advantageously protect the inner transmission rod to further minimize the risk for the electrical connection to be damaged. In a particular example, standard hollow pushing rods may be used and the inner transmission rod may be suited for insertion into the outer cylinder of such a standard hollow pushing rod. Using existing pushing rods is beneficial for the environment and is cost-effective.

[0018] In some examples, the transmission rod is slidably housed inside the outer cylinder. This facilitates replacement of the transmission rod if needed (upgrade transmission protocol, service a damaged conductor, etc.).

[0019] In some examples, the inner transmission rod comprises a central rod extending along at least two thirds of a length of the pushing rod, an uphole endcap and a downhole endcap, both fixed to the central rod, each of the uphole endcap and the downhole endcap receiving one of the two terminal connectors.

[0020] In some examples, the sensing apparatus comprises an uphole adapter configured to connect one of the two terminal connectors of an upmost pushing rod of the plurality of pushing rods to the uphole acquisition system, the uphole adapter comprising a quick connector and an uphole adapter electrical element having a shape complementary to said one of the two terminal connectors of theupmost pushing rod. In this manner, the quick connector can be removed from a previously pushed pushing rod and connected to the next one. It is thus easier and faster to install an additional pushing rod while maintaining data transmission during pushing steps.

[0021] For example, the quick connector can comprise a magnet, a spring clip, a push-pull connector, a latch connector, a bayonet connector, a threaded coupling, a spring loaded pin.

[0022] In some examples, the uphole adapter comprises a printed circuit board configured to convert a BNC coaxial signal carried by the electrical connectors of the pushing rods into a 12-pin LEMO® signal for transmission to the uphole acquisition system.

[0023] In some examples, the sensing apparatus comprises a downhole adapter configured to connect one of the two terminal connectors of a lowermost pushing rod of the plurality of pushing rods to the sensing unit of the probe, the downhole adapter comprising a downhole adapter electrical element having a shape complementary to said one of the two terminal connectors of the lowermost pushing rod.

[0024] In some examples, the downhole adapter comprises a printed circuit board configured to convert a 12-pin LEMO® signal generated by the sensing unit into a BNC coaxial signal for transmission by electrical conductors of the pushing rods.

[0025] In this manner, the multiple signals of the sensor unit is advantageously transmitted by a single canal. The connection is therefore reliable.

[0026] In some examples, the downhole adapter comprises a body and a spring, wherein the spring applies a force to the downhole electrical element so that the downhole adapter electrical element protrudes out of the body. The downhole electrical element is thus advantageously accessible for connection with the sensor unit for improved ergonomics and for ensuring a reliable connection.

[0027] In some examples, the printed circuit board of the downhole adapter is free to translate and rotate within the body of the downhole adapter. Thanks to this optional feature, the odds that the connection be mechanically damaged are reduced.

[0028] The present disclosure also pertains to a method of using a sensing apparatus, comprising: providing the sensing apparatus comprising: a probe comprising a sensor unit for soil analysis and a tip for penetration in the soil; an uphole acquisition system; and N pushing rods configured to be joined together end-to-end to push the probe under a subsurface of the soil, each of the N pushing rods comprising two terminal connectors that are electrically linked together by an electricalconductor, the plurality of pushing rods being configured to be electrically joined end-to-end to one another by their respective terminal connectors to form an electrical connection allowing transmission of data from the sensor unit to the uphole acquisition system; for each integer n between 1 and: pushing n pushing rods of the N pushing rods to advance the probe downhole, the n pushing rods defining an upmost pushing rod; and electrically and mechanically joining an additional pushing rod of the N pushing rods to the n pushing rods, by connecting a downhole end of the additional pushing rod to an uphole end of the upmost pushing rod; and pushing the electrically and mechanically joined N pushing rods to advance the probe downhole.

[0029] In some examples, the sensing apparatus comprises an uphole adapter configured to connect one of the terminal connectors of the upmost pushing rod to the uphole acquisition system, the uphole adapter comprising a quick connector and an uphole electrical element having a shape complementary to said one of the two terminal connectors of the upmost pushing rod, the method comprising, for each n between 1 and N: before pushing n pushing rods of the N pushing rods to advance the probe downhole, connecting the uphole adapter to one of the terminal connectors of the upmost pushing rod of the n pushing rods and to the uphole acquisition system; and after pushing n pushing rods of the N pushing rods to advance the probe downhole, disconnecting the uphole adapter from the upmost pushing rod of the n pushing rods.Brief Description of Drawings

[0030] Other features, details and advantages will be shown in the following detailed description and on the figures, on which:

[0031] FIG. 1 is an example of a known sensing apparatus, comprising a cable passing through each pushing rod to link the sensor unit to an uphole acquisition system.

[0032] FIG. 2 is a general illustration of an example of a sensing apparatus according to the present disclosure.

[0033] FIG. 3 is a schematic representation of an example wherein an additional pushing rod is being added to three joined pushing rods.

[0034] FIG. 4 is a detailed illustration of a pushing rod comprising, according to an example, an outer cylinder and a transmission rod, the transmission rod being here illustrated separated from the outer cylinder.

[0035] FIG. 5 shows the example of FIG. 4, wherein the transmission rod is inserted into the outer cylinder.

[0036] FIGS. 6 to 8 show detailed views of exemplary uphole endcap and the downhole endcap of a transmission rod.

[0037] FIGS. 9 and 10 show a particular example of a downhole adapter.

[0038] FIG. 11 shows a particular example of an uphole adapter.

[0039] FIG. 12 shows a flowchart of a method for using a sensing apparatus according to the present disclosure.Description of Embodiments

[0040] The present disclosure relates to a sensing apparatus for geomaterial penetration testing, in particular for soil testing.

[0041] Unless otherwise specified, the terms “uphole” and “downhole” respectively refer to a location that is vertically above ground, and to a location that is below ground, or under a subsurface of the soil, where the probe collects data. In a similar way, the terms “upmost” and “lowermost” refer respectively to the highest located and lowest located element of a series of elements (especially pushing rods).

[0042] FIG. 1 shows a sensing apparatus 1.1 of the prior art, comprising a probe 1.2 that is configured to be pushed downhole by a series of pushing rods 1.4, incrementally connected on top of each other.

[0043] In a conventional manner, the sensing apparatus 1.1 represented herein comprises a transmission cable 1.6, configured to allow transmission of data from a sensing unit located in the downhole probe 1.2, to an uphole acquisition system 1.3 for data processing. The cable 1.6 is strung through each pushing rod 1.4 and constitutes a continuous single electrical link comprising only two connections: one with the probe, and another one with the uphole systems.

[0044] As already discussed above, if the cable 1.6 or a pushing rod 1.4 were to be damaged, the entire cable would have to be pulled out of all the pushing rods, and the operation of introducing a cable through all the pushing rods must then be carried out again.

[0045] FIG. 2 shows a sensing apparatus 1 according to the present disclosure, which does not have this issue.

[0046] The sensing apparatus 1 comprises a probe 2 having a sensor unit 21 and a tip 22 for penetration in a soil 10. The tip 22 is shown here as being a cone tip 22 but alternative embodiments such as ball or vane-shaped tip may be used instead. Yet other shapes of penetrating instruments may be envisaged at the lower end of the probe 2.

[0047] The cone tip 22 of the probe 2 is configured to facilitate penetration of the probe 2 into the ground 10. For that purpose, it generally comprises a conical surface, on its downhole end. Other shapes suited for facilitated penetration may be used.

[0048] The sensor unit 21 may comprise at least one of: load cells, pressure transducers, geophones, inclinometers, magnetometers, cameras, and / or a combination thereof. The sensor unit 21 may also comprise other types of sensors suited for soil analysis.

[0049] The sensing apparatus 1 further comprises an uphole acquisition system 3, comprising a computer and a memory for receiving a data signal from the sensor unit 21. The uphole acquisition system 3 may further comprise a power supply. Other computing devices may serve as an acquisition system. Appropriate communication channels to distant computing devices or servers, or networks may be provided to facilitate transmission of data from the acquisition system to distant devices or users.

[0050] The sensing apparatus 1 also comprises a plurality of pushing rods 4 for pushing the probe 2 under the subsurface 11 of the soil 10. The pushing rods 4 are configured for pushing the probe 2 downhole. They are typically rectilinear. In particular, the pushing rods 4 may be of a substantially cylindrical / tubular shape. Such a tubular shape is particularly efficient for stiffness in compression, rendering the pushing rods 4 efficient for pushing the probe 2 downhole. The pushing rods 4 may be made of metal.

[0051] In a preferred embodiment, the probe is cylindrical. The diameter of the probe 2 may be substantially equal to the diameter of the pushing rods 4. Thus, the entire portion of the sensing apparatus 1 that is destined to penetrate the ground features no variation of size that may disturb the soil penetration.

[0052] Advantageously, all the pushing rods 4 are of identical design (shape, material, manufacturing process, etc.). This has economical and error-proof benefits when mounting the rods.

[0053] FIG. 3 shows that the pushing rods 4 each comprise two terminal connectors 41, 42. The term “terminal” here implies that the connectors are located at an end of the pushing rods 4.

[0054] Each pushing rod 4 further comprises an electrical conductor (61 on FIG. 6) that electrically links the two terminal connectors 41, 42 together. The electrical conductor and the two terminal connectors allow for a first pushing rod 4 to transmit data signal and / or power to a second pushing rod 4 adjacent to the first pushing rod 4, when one of the two terminal connectors 41, 42 of the first pushing rod is connected to one of the two terminal connectors 41, 42 of the second pushing rod 4.

[0055] It is thus implied that when the pushing rods 4 are joined end-to-end, they form an electrical connection between the uphole acquisition system 3 and the sensor unit 21, via the successive terminal connectors 41, 42 and the successive electrical conductor (61 on FIG. 6).

[0056] In a particular example, for each pushing rod, one of the two terminal connectors 41, 42 comprises a female connection, and the other terminal connector comprises a male connection.

[0057] FIG. 3 also shows that an upmost pushing rod may be electrically linked to the uphole acquisition system 3, for example by an uphole cable 33 extending from a terminal connector 41 of the upmost pushing rod 4 (represented here as not yet connected to an adjacent pushing rod 4). Similarly, a lowermost pushing rod 4 may be electrically linked to the sensor unit 21, for example by a downhole adapter (7 on FIGS. 9-10) or directly by a connector of the sensor unit 21.

[0058] As a consequence, each pushing rod 4 forms a segment of the electrical connection between the sensor unit 21 and the uphole acquisition system 3. In other words, the pushing rods 4 are connected electrically in series. Disconnecting a pushing rod 4 interrupts the continuity of the electrical connection.

[0059] FIG. 3 also shows that there may be a number n of pushing rods. Incrementally, an additional pushing rod can be added, to increase the number of pushing rods to [n+1],

[0060] As illustrated in FIG. 4, each pushing rod 4 may comprise an outer cylinder 5 and an inner transmission rod 6 extending through the pushing rod 4 and housed inside the outer cylinder 5. In FIG. 4, the inner transmission rod 6 is represented outside of the outer cylinder 5. The inner transmission rod 6 further features, at each end, one of the two terminal connectors 41, 42 of the pushing rod 4.

[0061] In a particular example, the transmission rod 6 is removably inserted into the outer cylinder 5 of the pushing rod 4. This facilitates maintenance, upgrading or recycling of the pushing rod. In some examples, the inner transmission rod 6 features a diameter that is strictly smaller than an inner diameter of the outer cylinder 5. Once the transmission rod 6 slides into place it can still slightly move to accommodate any minor misalignment.

[0062] The transmission rod 6 may comprise a central rod 62, as well as two endcaps: an uphole endcap 63 and a downhole endcap 64 that are both fixed to the central rod 62, each of the uphole endcap 63 and the downhole endcap 63 receiving a respective one of the two terminal connectors 41, 42. The central rod 62 may extend along at least two thirds of a total length of the pushing rod 4.

[0063] FIG. 5 shows the transmission rod 6 when mounted in the outer cylinder 5.

[0064] This figure shows that the outer cylinder 5 comprises mechanical fasteners 51, 52 for mechanically joining each pushing rod 4 end-to-end together. In particular, the mechanical fasteners 51, 52 can comprise a first threaded surface at a first end of the pushing rod 4 and a second threaded surface at the second end of the pushing rod 4, the second threaded surface being complementary to the first threaded surface. Preferably, the lower mechanical fastener 52 is an external thread and the upper mechanical fastener 51 is an inner thread.

[0065] Advantageously, each terminal connector 41, 42 is lodged inside each mechanical fastener (inside each threaded element). In other words, each of the two threaded surfaces extend externally around each of the two terminal connectors 41, 42. This enables simultaneously and automatically to establish a connection between the pushing rods.

[0066] In an advantageous example, each terminal connector 41, 42 may have an axisymmetric shape allowing a relative rotational movement between two adjacent pushing rods without disrupting the connection or damaging the terminal connectors.

[0067] As illustrated in FIG. 6, the electrical conductor 61 is housed inside an inner volume of the inner transmission rod 6. The electrical conductor 61 constitutes a link between the two terminal connectors 41, 42 located at each end of the transmission rod 6.

[0068] The electrical conductor 61 thereby extends inside the pushing rod 4. The electrical conductor 61 may typically present a length that is substantially equal to the length of the pushing rod.

[0069] The electrical conductor 61 thus extends from the uphole to the downhole endcaps (63, 64 on FIG. 4) through the central rod 62.

[0070] FIG. 7 shows a detailed example of a (lower) end of a pushing rod, where one can see a terminal connector 42 of a transmission rod 6 housed in an outer cylinder 5 of a pushing rod.

[0071] FIG. 8 shows an opposite (upper) end of a pushing rod with a (female) connector 41.

[0072] As discussed above in relation to FIG. 1, the sensing apparatus may comprise a downhole adapter 7 ensuring an electrical connection between the lowermost pushing rod and the probe / sensorunit. In some examples, the downhole adapter may be used for multiplexing a signal of the sensor unit 21.

[0073] FIGS. 9 and 10 show a downhole adapter 7 with a downhole adapter electrical element 71 in two different positions, i.e., positions relative to the body 72 of the downhole adapter.

[0074] The downhole adapter 7 comprises a spring 73 configured to apply a force to the downhole electrical element 71 so that, by default, the downhole adapter electrical element 71 protrudes out of the body 72. In fact, in this example, the electrical element 71 is slidably mounted and is able to slide parallel to an elongation direction of the body 72 of the downhole adapter 7. This enables a tip (lefthand side on FIG. 9) of the downhole electrical element 71 to protrude out of the body and to be easily manipulated by the operator connecting the downhole adapter 7 to the probe 2. The tip may for example protrude of a distance of at least 3mm.

[0075] In some examples, and in particular reference to FIG. 9, the downhole adapter 7 may comprise downhole adapter fasteners for mechanical connection with the probe 2 and with the lowermost pushing rod. In a particular example, the downhole adapter fasteners comprise threaded surfaces that are complementary to threaded surfaces of the pushing rods 4 and to a threaded surface of the probe 2. These fasteners may mirror the fasteners of the pushing rods.

[0076] As visible on FIG. 10, when it is electrically and mechanically connected to the probe 2 / sensor unit 21, the downhole electrical element 71 is pushed back into the body 72, thus compressing the spring 73. The opposite end of the downhole electrical element 71 (right-hand side on FIG. 10) becomes connectable to a pushing rod.

[0077] In some examples, the downhole electrical element 71 is further allowed to rotate inside the body 72, in order to facilitate connection and prevent breakage during the mechanical and / or electrical connection.

[0078] In a particular example, the downhole adapter 7 is configured to convert signal delivered by the sensor unit 21 housed in the probe 2 for transmission through the electrical connection formed by the pushing rods.

[0079] The signal delivered by the sensor unit 21 may comprise a multitude of signals. This signal may be converted, or multiplexed, by the downhole adapter 7 for transmission by the electrical connection formed by the pushing rods 4.

[0080] The downhole electrical element 71 may comprise an internal printed circuit board (PCB) including electronics for signal conversion.

[0081] The signals delivered by the sensor unit 21 may be transmitted to the PCB of the downhole adapter 7, by which the signals may be converted into a single signal suited for the electrical conductor 61 of the pushing rods 4.

[0082] In a particular example, the downhole electrical element 71 may comprise a 12-pin LEMO® connector for connection to the sensor unit 21. A similar or different connector may connect the downhole electrical element 71 to the lowermost pushing rod.

[0083] FIG. 11 shows an uphole adapter 8. Similarly to the connection between the probe and the lowermost pushing rod, the sensing apparatus may comprise an uphole adapter 8 for connection between the uppermost pushing rod and the acquisition system.

[0084] As mentioned below, the uphole adapter 8 may be used for de-multiplexing a signal transmitted by the pushing rods 4.

[0085] The uphole adapter 8 may comprise an uphole adapter electrical element 82 having a shape that is complementary to one of the two terminal connectors 41, 42 of the upmost pushing rod.

[0086] The uphole adapter 8 is configured to be connected to the uphole cable 33 that is linked to the uphole acquisition system 3.

[0087] In a particular example, the uphole adapter 8 is configured to convert the signal transmitted by the electrical connection of the plurality of joined pushing rods 4 for transmission to the uphole acquisition system 3.

[0088] The signal delivered by the electrical connection formed by the pushing rods 4, for example a single signal, may be converted, or de-multiplexed, by the uphole adapter 8 for transmission to the uphole acquisition system 3 via the uphole cable 33.

[0089] The uphole adapter 8 may comprise an uphole body 85, for example comprising a cylindrical hollow shape, in which the uphole electrical element 82 is lodged.

[0090] The uphole electrical element 82 may comprise an internal printed circuit board (PCB) including electronics for signal conversion, and the uphole electrical element 82 may have two connectors 83, 84 for respectively connecting an upper terminal connector of the uppermost pushing rod (e.g. a BNC coaxial connector) and a terminal end of the cable 33 (e.g. a 12-pin LEMO® protocol).

[0091] The uphole electrical element 82 may be slidably mounted inside the uphole body 85 of the uphole adapter. The uphole electrical element may be able to slide parallel to an elongation direction of the uphole adapter.

[0092] The uphole adapter 8 further comprises a spring 86 configured to apply a force to the uphole electrical element 82 which by default extends in an expanded position for connection to the uppermost pushing rod. An action on a button of the uphole holder 8 enables to retract the uphole electrical element 82 and compress the spring 86, to assist disconnecting the uphole adapter 8 from the uppermost pushing rod.

[0093] The uphole adapter 8 may thus comprise a quick connector 80. In a particular example, the quick-connector 80 comprises a smooth frustoconical surface, configured to fit into a threaded surface of the upmost pushing rods, for easy centering.

[0094] The uphole adapter 8 may further comprise a magnet 81 for an even easier and faster connection to the terminal connector of the upmost pushing rod. Advantageously, the magnets may be lodged around a base of the frustoconical surface. Alternatives to a magnet are possible such as a spring clip, a push-pull connector, a latch connector, a bayonet connector, a threaded coupling, a spring loaded pin.

[0095] In some examples, the sensing apparatus 1 comprises a multiplexing communication system connecting the sensing unit 21 to the uphole acquisition system 3. A multiplexing communication system is configured to transmit multiple signals or data streams simultaneously over a single communication channel. In this case, the single communication channel is formed by the electrical connection created by the joined pushing rods 4 and the uphole / downhole adapters. This allows for multiple data streams emitted from the sensor apparatus, for example comprising a plurality of sensors each emitting its own data stream, to be efficiently transmitted via a single stream formed by the joined pushing rods 4 (their terminal connectors and therebetween conductors).

[0096] In particular, the multiplexing communication system may comprise the downhole adapter 7 multiplexing data acquired from the sensing unit 21 and the uphole adapter 8 de-multiplexing data to feed to the uphole acquisition system 3, the uphole adapter 8 and the downhole adapter 7 being electrically linked by the electrical connection.

[0097] In this particular example, the action of “multiplexing” consists in combining multiple signals or data streams from the sensor unit 21 into a single stream of data.

[0098] De-multiplexing consists in the reverse process, as it involves separating the combined (or multiplexed) signal from the sensor unit 21 into its individual constituent signals or data streams.

[0099] The multiplexing may be temporal (i.e. a successive transmission of signals) or spectral (an overlap of signals over different frequencies ranges).

[0100] In some examples, each pushing rod 4 may comprise a single electrical conductor 61.

[0101] In some examples, the electrical connection is further configured to feed power to the sensor unit 21 in addition to the data signal. Several types of electrical conductors 61 may be suited for such an application. For example, power can be fed as DC, while data is transmitted as AC signal, e.g. up to 33 MHz.

[0102] For example the electrical conductor 61 may comprise any of the following cables: USB, power-over-ethernet cable, two-wires cables with serial data, USB-PD-like Custom Cables, coaxial cables, HDMI cables, combined multi-core cables, or a combination of them.

[0103] In this case, the electrical connection formed by the joined pushing rods allows a “two-way” transmission: power transmission from an uphole power supply to the downhole sensor unit 21, and data transmission from the downhole sensor unit 21 to the uphole acquisition system 3.

[0104] In a preferred embodiment, the electrical conductor 61 of each pushing rod 4 is a BNC coaxial cable. In this case, each pushing rod comprises a BNC coaxial cable linking the two terminal connectors 41, 42 of the pushing rod. The electrical connection is thus formed by a succession of electrically connected segments of BNC coaxial cables.

[0105] In some examples, the BNC coaxial cable can present a particular structure suited for such a two-way transmission (power and data).

[0106] In some examples, the electrical conductor 61 comprises a central conductor to carry the data signal, and a shield or outer conductor, to provide grounding and protection from electromagnetic interference (EMI).

[0107] In some examples the electrical conductor 61 can comprise a plurality of conducting elements. For instance, a central conducting element can carry the data signal, and an offset conducting elements can carry electrical current.

[0108] In other examples, power is transmitted over the coaxial cable alongside the signal, through a single electrical conductor 61.

[0109] In some examples, the sensor unit 21 comprises a 12-pin LEMO® connection which delivers a plurality of signals, for instance corresponding to various sensors of the sensor unit 21. The downhole adapter 7 thus comprises a complementary 12-pin LEMO® connector to receive the signals of the sensor unit. Such signal can be multiplexed by the downhole adapter 7 for transmission via the electrical connection of the pushing rods 4. In some examples, the signal(s) are multiplexed into a BNC coaxial signal for transmission by the transmission rod 6.

[0110] Other connection types than the 12-pin LEMO® and BNC coaxial signal may be envisaged within the scope of the present disclosure, such as for example a Quadrax® connector.

[0111] In reference to FIG. 12, a method for using a sensing apparatus as described hereabove will now be described.

[0112] Using the apparatus as described above may consist in providing the various necessary elements (i.e. pushing rods, probe, acquisition system); and pushing the probe downhole by incrementally adding a pushing rod (and applying a down force), connecting it to the pushing rods already present, until a desired depth is achieved. Measurements are made during each step of pushing down the probe.

[0113] A number N of pushing rods is provided, such that the cumulated length of the N pushing rods correspond to the desired maximum depth of the testing process.

[0114] Hence, the method 1000 may comprise a first step of providing 100 the apparatus as stated above. Some or all of the various features discussed above may be included in this step.

[0115] A first pushing rod is then connected to the probe and a force is applied to the first pushing rod to push down the probe. Successively, a pushing rod is added and electrically connected to the previous pushing rod until the number N of pushing rod is reached.

[0116] This process can be formulated as follows: for each integer number n from 1 to N-l, one must push 102 n pushing rods of the N pushing rods to advance the probe 2 downhole, the n pushing rods defining an upmost pushing rod; and electrically and mechanically join 104 an additional pushing rod of the N pushing rods to the n pushing rods, by connecting a downhole end of the additional pushing rod to an uphole end of the upmost pushing rod. Finally, one must push 105 the electrically and mechanically joined N pushing rods to advance the probe downhole. This terminates the process as the desired depth is then reached.

[0117] The connection between the various pushing rods may be made with the terminal connectors 41, 42 and with the fasteners 51, 52 discussed above.

[0118] In some examples, for each n between 1 and N: before pushing 102 n pushing rods of the N pushing rods to advance the probe downhole, the method comprises connecting 101 the uphole adapter 8 to one of the terminal connectors of the upmost pushing rod of the n pushing rods and to the uphole acquisition system 3; and after pushing 102 n pushing rods of the N pushing rods to advance the probe downhole, the method may comprise disconnecting 103 the uphole adapter 8 from the upmost pushing rod of the n pushing rods. The uphole adapter 8 may be connected to the upmost pushing rod 4 after or alternatively before this particular upmost pushing rod 4 is connected to the remaining of the already assembled pushing rods.

[0119] Another way of expressing the same method could be as follows: a method for using a sensing apparatus, comprising: providing the sensing apparatus comprising: a probe comprising a sensor unit for soil analysis and a cone tip for penetration in the soil; an uphole acquisition system; and a plurality of [n] pushing rods joined together end-to-end to push the probe under a subsurface of the soil, each of the pushing rods comprising two terminal connectors that are electrically linked together by an electrical conductor, the plurality of [n] pushing rods being electrically joined end-to-end to one another by their respective terminal connectors to form an electrical connection allowing transmission of data from the sensor unit to the uphole acquisition system; pushing the [n] joined pushing rods to advance the probe downhole, the n-th pushing rod defining an upmost pushing rod; joining to the [n] joined pushing rods an additional pushing rod, by connecting a downhole end of the additional pushing rod to an uphole end of the n-th pushing rod, thereby incrementing the number [n] of pushing rods to obtain [n+1] joined pushing rods, the additional pushing rod defining a [n+l]-th pushing rod; establishing the electrical connection via cooperation of one of the terminal connectors of the [n+l]-th pushing rod with one of the terminal connectors of the n-th pushing rod; pushing the [n+1] joined pushing rods to advance the probe further downhole. Finally, repeating these steps until reaching the desired depth.

[0120] Yet another way of expressing the same method could be as follows: a method for using a sensing apparatus, comprising: providing the sensing apparatus comprising: a probe comprising a sensor unit for soil analysis and a cone tip for penetration in the soil; an uphole acquisition system; and a plurality of pushing rods configured to be joined together end-to-end to push the probe under a subsurface of the soil, each of the pushing rods comprising two terminal connectors that are electrically linked together by an electrical conductor, the plurality of pushing rods being configuredto be electrically joined end-to-end to one another by their respective terminal connectors to form an electrical connection allowing transmission of data from the sensor unit to the uphole acquisition system; pushing a number [n] of pushing rods of the plurality of pushing rods to advance the probe downhole, the number [n] of pushing rods defining an upmost pushing rod; joining to the number [n] of pushing rods an additional pushing rod of the plurality of pushing rods, by connecting a downhole end of the additional pushing rod to an uphole end of the upmost pushing rod; establishing the electrical connection via cooperation of one of the terminal connectors of the additional pushing rod with one of the terminal connectors of the upmost pushing rod, thereby incrementing the number [n] of pushing rods, the additional pushing rod constituting an upmost pushing rod of a number [n+1] of pushing rods; pushing the number [n+1] of pushing rods to advance the probe further downhole; repeating the appropriate steps until reaching the desired depth.

Claims

ClaimsWhat is claimed is:

1. A sensing apparatus (1) for geomaterial penetration testing, comprising:a probe (2) comprising a sensor unit (21) for soil analysis and a tip (22) for penetration in the soil (10);an uphole acquisition system (3); anda plurality of pushing rods (4) configured to be joined together end-to-end to push the probe (2) under a subsurface (11) of the soil, each of the pushing rods (4) comprising two terminal connectors (41, 42) and an electrical conductor (61) electrically linking together the two terminal connectors (41, 42), the plurality of pushing rods (4) being configured to be electrically joined to one another end-to-end by one of their respective two terminal connectors (41, 42) to form an electrical connection allowing transmission of data from the sensor unit (21) to the uphole acquisition system (3).

2. The sensing apparatus (1) of claim 1, comprising a multiplexing communication system connecting the sensing unit (21) to the uphole acquisition system, the multiplexing communication system comprising a downhole adapter (7) multiplexing data acquired from the sensing unit (21), an uphole adapter (8) de-multiplexing data to feed to the uphole acquisition system (3), and the electrical connection connecting the uphole adapter (8) to the downhole adapter (7).

3. The sensing apparatus (1) of claim 1, wherein the electrical connection is further configured to feed power to the sensor unit (21).

4. The sensing apparatus of claim 1, wherein the electrical conductor (61) is a BNC coaxial cable.

5. The sensing apparatus of claim 1, wherein the two terminal connectors (41, 42) comprise a first terminal connector (41) and a second terminal connector (42), wherein the first terminal connector (41) is a female connector, and the second terminal connector (42) is a male connector.

6. The sensing apparatus of claim 1, wherein each pushing rod (4) comprises an outer cylinder (5) and an inner transmission rod (6) housed inside the outer cylinder (5), and the electrical conductor (61) comprises a cable contained inside said inner transmission rod (6).

7. The sensing apparatus of claim 6, wherein the transmission rod (6) is slidably housed inside the outer cylinder (5).

8. The sensing apparatus of claim 6, wherein the inner transmission rod (6) comprises a central rod (62) extending along at least two thirds of a length of the pushing rod (4), an uphole endcap (63) and a downhole endcap (64), both fixed to the central rod (62), each of the uphole endcap (63) and the downhole endcap (63) receiving one of the two terminal connectors (41, 42).

9. The sensing apparatus of claim 1, comprising an uphole adapter (8) configured to connect one of the two terminal connectors (41, 42) of an upmost pushing rod of the plurality of pushing rods (4) to the uphole acquisition system (3), the uphole adapter (8) comprising a quick connector (80) and an uphole adapter electrical element (82) having a shape complementary to said one of the two terminal connectors (41, 42) of the upmost pushing rod.

10. The sensing apparatus of claim 9, wherein the uphole adapter (8) comprises a printed circuit board configured to convert a BNC coaxial signal carried by the electrical connectors (41, 42) of the pushing rods (4) into a 12-pin LEMO® signal for transmission to the uphole acquisition system (3).

11. The sensing apparatus of claim 1, comprising a downhole adapter (7) configured to connect one of the two terminal connectors (41, 42) of a lowermost pushing rod of the plurality of pushing rods (4) to the sensing unit (21) of the probe (2), the downhole adapter (7) comprising a downhole adapter electrical element (71) having a shape complementary to said one of the two terminal connectors (41, 42) of the lowermost pushing rod.

12. The sensing apparatus of claim 11, wherein the downhole adapter (7) comprises a printed circuit board configured to convert a 12-pin LEMO® signal generated by the sensing unit (21) into a BNC coaxial signal for transmission by electrical conductors (41, 42) of the pushing rods (4).

13. The sensing apparatus of claim 11, wherein the downhole adapter (7) comprises a body (72) and a spring (73), wherein the spring (73) applies a force to the downhole electrical element (71) so that the downhole adapter electrical element (71) protrudes out of the body (72).

14. The sensing apparatus of claim 13, wherein the printed circuit board of the downhole adapter (7) is free to translate and rotate within the body (72) of the downhole adapter (7).

15. A method for using a sensing apparatus (1), comprising:providing (100) the sensing apparatus comprising:a probe (2) comprising a sensor unit (21) for soil analysis and a tip (22) for penetration in the soil (10);an uphole acquisition system (3); andN pushing rods (4) configured to be joined together end-to-end to push the probe (2) under a subsurface (11) of the soil, each of the N pushing rods (4) comprising two terminal connectors (41, 42) that are electrically linked together by an electrical conductor (61), the plurality of pushing rods (4) being configured to be electrically joined end-to-end to one another by their respective terminal connectors (41, 42) to form an electrical connection allowing transmission of data from the sensor unit (21) to the uphole acquisition system (3);for each integer n between 1 and (N-l):pushing (102) n pushing rods (4) of the N pushing rods (4) to advance the probe (2) downhole, the n pushing rods defining an upmost pushing rod; and electrically and mechanically joining (104) an additional pushing rod of the N pushing rods (4) to the n pushing rods (4), by connecting a downhole end of the additional pushing rod to an uphole end of the upmost pushing rod; and pushing (105) the electrically and mechanically joined N pushing rods (4) to advance the probe (2) downhole.

16. The method of claim 15, wherein the sensing apparatus (1) comprises an uphole adapter (8) configured to connect one of the terminal connectors (41, 42) of the upmost pushing rod to the uphole acquisition system (3), the uphole adapter (8) comprising a quick connector (80) and an uphole electrical element (82) having a shape complementary to said one of the two terminal connectors (41, 42) of the upmost pushing rod, the method comprising, for each n between 1 and N:before pushing (102) n pushing rods (4) of the N pushing rods (4) to advance the probe (2) downhole, connecting (101) the uphole adapter (8) to one of the terminal connectors (41, 42) of the upmost pushing rod (4) of the n pushing rods and to the uphole acquisition system (3); and after pushing (104) n pushing rods (4) of the N pushing rods (4) to advance the probe (2) downhole, disconnecting (103) the uphole adapter (8) from the upmost pushing rod of the n pushing rods.

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