Pressure probe device

Abstract

Device (10) for pressure sounding with a probe (12) to be pressed into a subsurface (11), wherein the probe (12) can be attached to one end of a drill string (25) and wherein, for pressure sounding, the drill string (25) with the probe (12) in front can be rotated into the subsurface (11) by a drive, characterized in that the probe (12) can be connected to the drill string (25) in a rotationally decoupled manner, wherein the device (10) comprises a rotary bearing (18) which is arranged above a sensor of the probe (12) and wherein the rotary bearing (18) is a ball bearing, cylindrical bearing, barrel bearing or plain bearing, wherein the drill string (25) has a drill bit (21) and wherein the device (10) further comprises a probe carrier (26) of the probe (12) and a locking device (27), wherein the rotary bearing (18) is arranged between the probe carrier (26) and the locking device (27) in the drill string (25).

Description

[0001] The invention relates to a device for pressure sounding according to the preamble of claim 1. Furthermore, the invention relates to an arrangement according to claim 10.

[0002] A well-known and frequently used method for conducting in-situ geotechnical investigations is cone penetration testing (CPT), in which a probe is driven into the subsurface. The resulting tip resistance (cone) and shaft friction on the probe provide information about the properties, particularly the shear strength, of the subsurface or soil. To drive the probe into the subsurface, a probe rod is used, to which the probe can be attached at its lower end.

[0003] In the traditional method, a cable is used within the probe rod to supply the probe with power and to allow verification of the acquired data during the pressure test. The use of an autonomous probe with its own battery power supply and data logger for data storage is also known. Furthermore, the autonomous probe can be equipped with a modem for wireless data transfer (e.g., acoustic) within the probe rod.

[0004] In the "Top Push Technique," the probe, along with the probe rod, is pushed into the subsurface by a suitable system or drive mechanism. This system can be a specialized device for pressure testing. Alternatively, it can be a drilling rig or a device for conducting boreholes. These systems can be installed on the subsurface or ground being investigated, for example, on land, underwater, or on a floating platform (e.g., a drillship).

[0005] As an alternative to a probe string, a drill string, such as those used for core drilling, can also be used to conduct a pressure test. The drill string is equipped at one end with a drill bit that has a central opening. Typically, one or more reamers are located above the drill bit. Flushing holes in the area of ​​the drill bit allow the use of a flushing medium, in particular a flushing fluid or a flushing gas, preferably air, to, for example, stabilize the borehole and flush out drill cuttings generated during rotary drilling. For the pressure test with the drill string, the sensor unit of the pressure probe is inserted through the drill bit and is located below the drill string.For anchoring in the drill string, the probe can either be equipped with a locking unit or a support tube can be used that is locked into the drill string and supports the probe during the pressure test; as described, for example, in DE 10 2018 006 901 A1. The drill string with the probe advancing can then be pushed into the ground. In this case, the drill string is also used as the sounding rod in the "top push technique". Alternatively, the probe can be pushed into the ground with a separate drive unit (downhole operation).

[0006] The use of the probe in conjunction with a drill string has the advantage that pressure tests and core drilling, e.g. for obtaining core samples or other borehole measurements, can be carried out alternately in the same borehole.

[0007] The use of special probe rods, on the other hand, has the advantage that it is possible to work with rods optimized for the pressure test with a smaller outer diameter, thereby reducing the force required for the pressure test.

[0008] The penetration depth achievable in a compression test depends not only on the force applied to the drive mechanism but also, and especially, on the geotechnical properties of the soil. High skin friction is a frequent reason for aborting a compression test. Skin friction, which opposes the drive force during the compression test, acts on both the probe and the probe or drill string, and therefore increases with increasing penetration depth.

[0009] To achieve greater penetration depths with the same driving force, vibration can be used. The vibration of the rod reduces skin friction during the compression test. However, in the so-called Vibro Cone Penetration Test, the vibration also affects the probe measurements, meaning that the results of compression tests performed with and without vibration are not directly comparable.

[0010] To achieve a greater probing depth, the rod can be rotated by the drive mechanism. However, the rotation caused by the rotating probe also affects the measured pressure data, making comparative measurements necessary.

[0011] The present invention is based on the objective of creating a device and a method for pressure sounding with which the skin friction of the rod is reduced without thereby influencing the sounding result of the probe.

[0012] A solution to this problem is described by the features of claim 1. It is provided that the probe can be connected to the drill string in a rotationally decoupled manner, wherein the device comprises a rotary bearing arranged above a sensor of the probe, and wherein the rotary bearing is a ball bearing, cylindrical bearing, barrel bearing, or plain bearing, wherein the drill string has a drill bit, and wherein the device further comprises a probe carrier for the probe and a locking device, the rotary bearing being arranged between the probe carrier and the locking device in the drill string. This rotational decoupling of the probe from the string, in particular the probe string or the drill string, allows the entire string to rotate during the pressure test to reduce skin friction without the probe rotating with it.The probe thus experiences resistance only parallel to the longitudinal axis of the rod. Any additional friction factors or components that would arise from further rotation and are difficult to calculate are thereby avoided. By rotating the probe rod, greater probing depths can be achieved than previously possible, specifically by reducing the friction on the rod's skin. The friction on the probe itself remains unaffected by this solution.

[0013] Furthermore, the invention preferably provides that a rotary bearing is arranged above a sensor of the probe on the probe carrier. It is conceivable that the rotary bearing is a slip ring. This slip ring can have sliding contacts to transmit, for example, energy and / or data.

[0014] Furthermore, it is conceivable that the rotary bearing is attached to a drilling string, a support pipe of a drilling string, or directly to a drilling string, or can be coupled or detachably coupled in a locking unit. In this way, the rotary bearing can be used flexibly with both a sounding rod and a drill string. This flexible design of the device or rotary bearing according to the invention enables flexible application.

[0015] Another advantageous embodiment of the present invention provides that the probe can be wirelessly powered via the rotary bearing, e.g., via sliding contacts. Similarly, the invention allows the rotary bearing to wirelessly exchange data between the probe and the rod or a control unit, which may be positioned at an upper end of the rod, e.g., via sliding contacts or via an acoustic, optical, or radio connection. This eliminates the need for a complicated and error-prone cable connection between the probe and the rod. Particularly when using a slip ring, reliable power and data transfer between the probe and a control unit above the bearing can be achieved via sliding contacts. With this solution, as with conventional CPT probing, no cable for power or data transfer needs to be carried in the probe string.For the use of a cable in conjunction with the rotary bearing, the cable would have to be routed axially through the bearing to prevent twisting. If a cable is not used, an autonomous probe can be employed, which can, for example, integrate a data logger and / or a power supply. By using sliding contacts or alternative contacts for wireless data transmission, real-time data monitoring can be performed even when working with an autonomous probe, or wireless data retrieval is possible immediately after use. A modem can be used for this purpose, which can be positioned in the probe string (ideally in the uppermost section of the probe installation, above the bearing) for data transmission. If the modem and the probe have separate power supplies, wireless data transmission in the area of ​​the rotary bearing is sufficient.

[0016] Alternatively or additionally, the probe could have its own power supply, control system, and data recording capabilities. For example, a battery or accumulator could be integrated into the probe, providing sufficient electrical energy to power the probe and / or measuring devices for the duration of the pressure sounding. Furthermore, a transmitter and / or receiver, particularly a modem, could be integrated into the probe, support tube, or locking unit for wireless transmission of the acquired data within the sounding string. This wireless data transfer allows for the evaluation of the acquired data and measurement quality during the sounding test, even when the probe is operating autonomously. This online evaluation makes the entire pressure sounding process particularly efficient.

[0017] It is preferably conceivable that the probe or the linkage has a sensor that can determine whether the probe is moving relative to the linkage or is stationary. This sensor can be controlled or read online via the aforementioned data transfer device.

[0018] Another embodiment of the present invention provides that the rotary bearing can be locked during pressure sounding, thereby preventing relative movement between the rod and the probe, for example, for comparative measurements. In this way, the effect of skin friction on the probe string can be investigated depending on the soil conditions. From this additional data, for example, further properties of the probed subsurface can be determined.

[0019] Claim 10 claims an arrangement for solving the problem mentioned at the outset.

[0020] Preferred embodiments of the invention are explained below with reference to the drawing. Only the embodiments of Fig. 3 and Fig. 4 to the invention. The ones in the Fig. 1, Fig. 2 and Fig. The five exemplary embodiments shown are to be understood as purely illustrative and are not encompassed by the invention. Fig. 1 a schematic representation of a pressure sounding system, Fig. 2 a schematic representation of a section of a probe rod with a probe, Fig. 3 a schematic representation of a section of a drill string with a probe, Fig. 4 a schematic representation of a further embodiment of the drill string according to Fig. 3 and Fig. 5 a schematic representation of the probe rod according to Fig. 2 using a rinsing fluid.

[0021] The device 10 shown in the figures can be used to perform pressure soundings in a subsurface 11. For example, as shown in the Fig. Figure 1, in a highly schematic representation, shows a probe 12, which is attached or coupled to a rod 13, being pressed into the ground 11. This ground 11 can be either soil on land or underwater. The rod 13 with the probe 12 can therefore, for example, be arranged as shown in the Fig. Figure 1 shows that the material is driven into the subsurface 11 by a system 14. This system 14 can, for example, be assigned to a vehicle 15 or, in the case of offshore drilling, to a drilling platform, a ship, or a robot on the seabed.

[0022] In order to achieve greater drilling depths or sounding depths for the pressure sounding measurements, the probe 12 is not only pressed in the sounding direction 16 parallel to a longitudinal axis of the rod 13, but also around this axis according to the Fig. The rod 13 rotates in the direction of arrow 17 shown in Figure 2. This additional rotational movement of the rod 13 can also be performed by the system 14. This rotation reduces the friction on one side of the rod 13. However, if the probe 12 also rotates, this rotational movement can also have a negative impact on the pressure sounding measurement data.

[0023] According to the invention, a rotary bearing 18 is provided between the probe 12 and the linkage 13, or integrated into the linkage 13. In the case of the Fig. In the embodiment of the present invention shown in Figure 2, the rod 13 is designed as a probe rod 19. In this embodiment, the first probe rod 20 has the pivot bearing 18 above the probe. The pivot bearing 18 can, unlike the illustration in Figure 2, be configured as follows: Fig. 2, may also be arranged in a different position, as according to the invention on the probe 12 above a sensor or further above on the probe rod 19. In pressure sounding, i.e. when the probe rod 19 is driven into the subsurface 11 in the sounding direction 16, the probe 12 is thus rotationally decoupled from the probe rod 19.

[0024] To further reduce the skin friction of the probe rod 19, it can be, as in the Fig. Figure 2 shows a drill bit 21 located above the probe 12 and above the rotating bearing 18. This drill bit 21 bores a hole following the sounding direction, with a diameter larger than that of the sounding rod 19. The use of a drill bit 21 is only possible if the sounding rod 19 is rotatable. In addition, the sounding rod 19 may also have additional reamers 22, positioned opposite to the sounding direction 16 of the drill bit 21. These reamers 22 further break up rock or keep clear an annular space 23 that forms around the sounding rod 19 during drilling.

[0025] Furthermore, it is conceivable that the probe string 19 has flushing holes, not shown, preferably in the area of ​​the drill bit 21. During the pressure sounding process, the flushing medium, in particular a liquid or gas, can be guided through the rod 19 into the annular space 23 via these flushing holes. Fig. 5 is schematically shown as it is in the Fig. The probe rod 19 shown in Figure 2 is driven into the subsurface 11 with the probe 12. It is clearly visible how the annular space 23 is created by the drill bit 21. This annular space 23 is then... Fig. In the embodiment shown in section 5, the area is flushed out by the flushing medium. The flow direction of the flushing medium is shown in the Fig. 5 is represented by arrows 24. By using the drill bit 21 and the flushing medium in conjunction with the probe rod 19 and the rotationally decoupled probe 12, particularly large probe depths can be achieved.

[0026] The invention provides that the probe 12 is rotationally decoupled from a drill string 25 by the rotary bearing 18. In the Fig. 3 and Fig. Figure 4 shows, for illustrative purposes, only a lower section of the drill string 25. The drill string 25 also has a drill bit 21 for core drilling and flushing openings. In the case of the Fig. In the embodiment shown in Figure 3, the rotary bearing 18 is arranged between a probe carrier 26 and a locking unit 27. It is conceivable that the rotary bearing 18 is connected or coupled to either the locking unit 27 or the probe carrier 26. For the sounding measurements, the locking unit 27 is inserted into the drill string 25 and locked at its lower end for pressure measurements. The locking unit 27 can be positioned in and retrieved from the drill string 25 by means of a catch 28. The rotary bearing 18 decouples the probe 12 with the probe carrier 26 from the rest of the drill string 25 with respect to rotation. In this way, a pressure sounding can be carried out with the drill string 25, just as described previously for the sounding rod. This allows the drill string 25 to be used both for obtaining drill cores and for carrying out the described pressure sounding.

[0027] In the Fig. 4 shows a further embodiment of the invention. In addition to the embodiment of the Fig. 3. The probe 12 or the probe carrier 26 is supported by a support tube 29 with the locking unit 27. The probe carrier 26 has a pin 31 for detachable coupling with the support tube 29. The probe carrier 26 can be temporarily coupled to and uncoupled from the support tube 29 via this pin 31. The rotary bearing 18 can, for example, be integrated into the support tube 29 or into the locking unit 27. The use of the support tube 29 allows the probe 12 or the probe carrier 26 to be used more flexibly and / or reduces the required overall length of the probe, which can be particularly advantageous in robotic applications.

[0028] It is also conceivable that the probe 12 is energy self-sufficient, i.e., that it is equipped, for example, with batteries or a rechargeable battery that ensures a sufficient electrical power supply for the probe's operation. Equally conceivable, however, is that the probe 12 is supplied with electrical energy via the rotary bearing 18. In this case, it is conceivable that cables are routed through the linkage 13, via which the probe 12 can be supplied with electrical energy via the rotary bearing 18. It is also conceivable that the probe 12 has corresponding transmitters and receivers for wireless communication with a remote station. Likewise, it is conceivable that the probe 12 or the locking unit 27 has a modem 30, via which data exchange with the probe 12 can take place.For supplying the probe 12 with electrical energy and for exchanging data via the rotary bearing 18, the use of a slip ring with sliding contacts is preferred.

[0029] It should be expressly noted that the present invention is not limited to the illustrated embodiments. Rather, it is intended that the invention also includes further embodiments.

Claims

[1] Device (10) for pressure sounding with a probe (12) to be pressed into a subsurface (11), wherein the probe (12) can be attached to one end of a drill string (25) and wherein, for pressure sounding, the drill string (25) with the probe (12) in front can be moved into the subsurface (11) by a drive in a rotating manner, characterized by , that the probe (12) can be connected to the drill string (25) in a rotationally decoupled manner, wherein the device (10) comprises a rotary bearing (18) which is arranged above a sensor of the probe (12) and wherein the rotary bearing (18) is a ball bearing, cylindrical bearing, barrel bearing or sliding bearing, wherein the drill string (25) has a drill bit (21) and wherein the device (10) further comprises a probe carrier (26) of the probe (12) and a locking device (27), wherein the rotary bearing (18) is arranged between the probe carrier (26) and the locking device (27) in the drill string (25). [2] Device (10) for pressure sounding according to claim 1, characterized by , that the rotary bearing (18) is arranged above the sensor of the probe (12) on the probe carrier (26). [3] Device (10) for pressure sounding according to claim 1, characterized by , that the probe (12) can be locked in a drill string of the drill string (25) by the locking unit (27), wherein the rotary bearing (18) is integrated into the locking unit (27) or can be coupled to the locking unit (27) or the rotary bearing (18) is integrated into the probe carrier (26) of the probe (12). [4] Device (10) for pressure sounding according to claim 1 or 3, characterized by, that the probe (12) can be locked in the drill string (25) by the locking unit (27) and a support tube (29) positioned between the probe (12) and the locking unit (27), wherein the rotary bearing (18) is integrated into the support tube (29) or into the probe carrier (26) or can be coupled to the support tube (29). [5] Device (10) for pressure sounding according to any of the preceding claims, characterized by , that energy transfer between the drill string (25) and the probe (12) takes place through the rotary bearing (18) via cable or wirelessly, in particular via sliding contacts. [6] Device (10) for pressure sounding according to one of the preceding claims, characterized by , that data transfer between the drill string (25) and the probe (12) takes place through the rotary bearing (18) via cable or wirelessly, in particular via sliding contacts, radio or optically. [7] Device (10) for pressure sounding according to one of the preceding claims, characterized by , that the probe (12) or the support tube (29) or the locking unit (27) has its own power supply and / or a transmitter and / or a receiver, preferably a modem (30), for exchanging data with a control unit, wherein the transmitter and / or the receiver is assigned to one end of the drill string (25) opposite the drill bit (21). [8] Device (10) for pressure sounding according to any of the preceding claims, characterized by , that a relative movement between the drill string (25) and the probe (12) can be detected by a sensor assigned to the probe (12). [9] Device (10) for pressure sounding according to any of the preceding claims, characterized by , that the rotary bearing (18) can be locked, thereby preventing relative movement between the drill string (25) and the probe (12) for example for a comparative measurement. [10] Arrangement for carrying out pressure soundings with a drill string (25) and with a device (10) according to claim 1.

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