RF borehole probe system and method for operating an RF borehole probe system

Abstract

The invention relates to an RF borehole probe system and to a method for operating an RF borehole probe system, comprising at least: - a probe body (2), - an X-ray source (4) which is arranged in the probe body (2), - a detector (5) for fluorescence and / or scattered radiation, said detector (5) being arranged in the probe body (2), and - an analysis device (8) for analyzing the output signals generated by the detector (5), wherein the analysis device (8) is designed to analyze the elements of the irradiated material, and the analysis device (8) is additionally designed to determine the specific density of the irradiated material and / or to determine the distance between the probe body (2) and a borehole wall (12).

Description

[0001] RF borehole probe system and method for operating an RF borehole probe

[0002] The invention relates to an RF (X-ray fluorescence) borehole probe system and a method for operating an RF borehole probe.

[0003] To determine whether mineral extraction is economically viable, mineral prospecting involves analyzing the chemical and mineralogical composition of rocks. This can be done by drilling a borehole into the rock and moving a borehole probe up and down within the borehole. A sensor on the probe detects signals from the surrounding area, which can then be evaluated to detect and measure the concentration of elements present.

[0004] X-ray fluorescence borehole probes are known, which contain an X-ray source and a fluorescent detector, with detector output signals being evaluated for the aforementioned detection and concentration measurement. It is desirable to improve the detection and concentration measurement, particularly their reliability and accuracy. It is also desirable to enable detection and measurement in an environmentally friendly, safe, cost-effective, and continuous manner.

[0005] Known from the prior art is RU 169 39 92 C, which discloses an X-ray radiometric borehole measurement used in the prospecting and exploration of mineral deposits. This publication also describes the ability to determine molybdenum content in rock and ore.

[0006] Also known is EP 0 184 898 A1, which discloses a survey in which radiation scattered by a borehole environment and surrounding earth information is analyzed to provide indications of certain preselected borehole and earth formation properties. The document discloses the interpretation of detector signals to obtain indications of tool spacing.

[0007] Also known is EP 2 223 166 A2, which discloses a tool for use in the hydrocarbon industry, in particular a borehole imaging tool, that utilizes an X-ray generator. Also known is CA 2 519 740 A1, which discloses drilling and surveying boreholes. This document specifically discloses the estimation of distances to bed boundaries.

[0008] GB 2 444 801 A discloses an apparatus and method for evaluating a formation surrounding a borehole using an X-ray generator.

[0009] US 4,628,202 A discloses a radioactivity borehole logging system and methods and devices for identifying the density and lithology of subterranean earth formations. The document further discloses the storage of a so-called short-space count rate and the storage of a spectrum or count rate spectra.

[0010] WO 2021 / 108847 A1 discloses a blasthole logging system and a modular borehole logging tool.

[0011] The technical problem is to create a borehole probe system and a method for operating a borehole probe that enable reliable and accurate analysis of rock in the vicinity of a borehole probe, whereby such a system can be implemented in an environmentally friendly, safe and cost-effective manner and enables continuous measurement.

[0012] The solution to the technical problem is achieved by the subject matter having the features of the independent claims. Further advantageous embodiments of the invention are set forth in the subclaims.

[0013] An RF borehole probe system is proposed. The system comprises at least one probe body. This can include a housing, with components of the borehole probe system arranged in an interior volume of the housing. The housing can also be referred to as a probe casing. The probe body, in particular the housing, can be made of metal. The probe body can have a lower end and an upper end. When the borehole probe is inserted into a borehole as intended, the lower end of the probe body is arranged below the upper end along the direction of gravity. The upper end therefore refers to the end of the probe body closer to the surface during intended use in the borehole.At the upper end, which can also be referred to as the cable-side end and is the end opposite the lower end along a longitudinal axis of the probe body, the probe body can comprise an interface for the mechanical attachment of a cable or rope, which serves in particular to transmit a driving force for moving the probe body in the borehole, i.e. to move the probe body up and down in the borehole. The driving force can be generated by a corresponding device, which is generally arranged outside the borehole. For example, a drive cable or rope can be guided in a known manner to a drive device, for example a driven pulley, in order to generate the driving force. It is also possible for an interface for signal and / or data transmission to be arranged on the probe body at the upper end.The interface can, for example, be designed to enable a plug-in connection with a data cable, which can also be referred to as a logging cable. It is conceivable that such a data cable also serves as a drive cable or that a drive cable also serves for data transmission. For example, a drive cable can have electrical wires for signal and / or data transmission. However, it is also possible for a drive cable and a data cable to be designed separately from one another. It is possible for the probe system to comprise a communication device, which is arranged in particular in the probe body and can transmit signals via the interface. This communication device can, in particular, enable DSL-based communication. Of course, other forms / types of communication are also conceivable.

[0014] Furthermore, the probe body can comprise an interface for establishing an energy connection, i.e., a power supply to components of the probe system. This can also be used to charge an energy storage device of the probe system, which can be arranged in the probe body. This interface can also be arranged at the upper end. The probe system can therefore be a battery-operated probe system, with the energy storage device of the probe system, which can be arranged in the probe body, supplying components of the probe system with electrical energy.

[0015] Furthermore, the borehole probe system comprises precisely one X-ray source or multiple X-ray sources arranged in the probe body. This serves to generate X-ray radiation, which is then emitted into the environment of the probe body. Preferably, the radiation source is designed as an X-ray tube, wherein a target material of the X-ray tube can be, for example, molybdenum, but also rhodium or another material known to those skilled in the art. The target material can in particular be an anode material of the X-ray tube, onto which electrons from a cathode of the X-ray tube accelerate under high voltage impact. The functioning of an X-ray tube is known to those skilled in the art. However, it is also possible for the X-ray source to be a piezoelectric effect-based X-ray source or a laser-based X-ray source.

[0016] It is possible that the probe body has one or more X-ray windows through which radiation generated by the X-ray source can escape from the probe body into the environment.

[0017] The borehole probe system further comprises a detector for fluorescence and / or scattered radiation. The fluorescence radiation is excited by the X-rays generated by the X-ray source. Scattered radiation refers to the portion of the radiation generated by the X-ray source that is scattered toward the detector and can also include or be gamma radiation. The material irradiated by the X-ray source, which emits the described fluorescence radiation and / or scatters scattered radiation when irradiated, can be the borehole fluid or the drilled rock, i.e., the material surrounding the borehole. The detector is also arranged in the probe body, in particular in the housing. It is conceivable that the fluorescence radiation as well as the scattered radiation from the environment enters the probe body through the previously explained X-ray window and is then detected by the detector.However, it is also possible for the probe body to comprise a plurality of X-ray radiation windows, wherein, for example, a first X-ray radiation window is arranged and / or designed such that radiation generated by the X-ray radiation source can be emitted into the environment, while a further X-ray radiation window can be designed and / or arranged such that X-ray radiation and / or scattered radiation can be emitted from the environment to the detector.

[0018] The borehole probe system further comprises an evaluation device for evaluating the output signals generated by the detector, wherein the evaluation device is designed for elemental analysis of the irradiated material. An evaluation device can be designed as a microcontroller or integrated circuit, or can comprise one of these. In particular, the evaluation device can comprise a so-called multi-channel analyzer. This serves, in a known manner, to measure a statistically distributed sequence of electrical pulses of varying amplitude in order to determine their frequency distribution. Based on the output signals of such a multi-channel analyzer, a spectrum of the detected radiation can be determined, e.g., in the form of a histogram.It is also possible for the evaluation device to comprise a digitizing device that digitizes the detector's output signals, in particular in such a way that a computer-implemented signal analysis of the generated output signals can be performed. Such a digitizing device can be designed, in particular, as an ADC converter.

[0019] The evaluation device can further be designed for element analysis, which includes, for example, element detection / identification and, if appropriate, element quantification. This makes it possible to determine the chemical composition of the material of the borehole wall and / or the borehole fluid. The element analysis can be carried out based on the spectrum, i.e. a spectral profile, of the radiation detected by the detector. For the analysis, so-called spectral lines in a low-energy range, preferably a range from 0 keV (exclusive) to 45 keV (inclusive), can be used. However, the range can also extend from 0 keV (exclusive) to a value greater than 45 keV. A spectral line can be a local maximum in the spectrum. An intensity and a width can be assigned to a spectral line.Thus, the spectral line can cover a (narrow) frequency range whose half-width can be referred to as the width of the spectral line.

[0020] According to the invention, the evaluation device is additionally designed to determine a specific density of the irradiated material. Alternatively or additionally, the evaluation device is designed to determine a distance between the probe body and a borehole wall.

[0021] The specific density can be determined from the spectral profile of the detected radiation, in particular from a profile curve and / or a profile property. In particular, the so-called bremsstrahlung can be identified in the spectral profile, whereby the specific density is determined as a function of the curve and / or properties, e.g. an intensity maximum, of the bremsstrahlung, in particular because the energetic maximum of the bremsstrahlung varies with the specific density. The determination of the specific density can preferably be based on assignment. In addition, different specific densities can be assigned to different profiles or properties, for example as part of a calibration or as a result of preliminary tests. This information, i.e. information about the specific density, the profile orThe properties and their correlation to one another can then be stored, in particular in a storage device of the probe system, for example in the form of a database. It is then possible to determine a spectral profile of the detected radiation, in particular the bremsstrahlung, or its property(ies), and then to determine the specific density as the specific density associated with a profile or property that deviates no more than a predetermined amount from the signal-based determined profile / property.

[0022] The specific density determined in this way can then be used to characterize the lithology, but also to correct the elemental analysis of the drilled rock. In particular, a density-related scattering component of the detected radiation can be taken into account in the elemental analysis, as it represents a specific property of the irradiated material. The intensity, particularly the spectral intensity, of the detected radiation changes depending on the specific density of the irradiated material. The higher the specific density, the lower the intensity will be. It is therefore possible, with a known specific density, to change the intensity of the detected radiation depending on the density. For example, the intensity can be increased more for a higher specific density than for a comparatively lower specific density.Then the elemental analysis can be carried out based on or depending on the density-dependent corrected / modified intensity.

[0023] The specific density can also be used for elemental analysis of the borehole fluid. In other words, the material of the borehole fluid can be determined as a function of the specific density. Furthermore, a hydraulic property or change in properties in the borehole, e.g. an inflow or outflow of borehole fluid, can be determined, in particular detected, as a function of the specific density. This also makes it possible to generate location-referenced information on inflows or outflows in the borehole. Location-referenced information here refers to information to which location information is assigned. The location information can be determined in a known manner, e.g. as depth information, which can be determined using sensors, for example. The depth information can be determined, for example, as a function of a position / angle detection device of a rope / cable transmitter device, which sets the length of the rope / cable in the borehole and thus the depth.It is also conceivable that an acceleration sensor could be used to determine position. Depth information could also be determined using a pressure sensor, with the depth being determined based on the detected pressure.

[0024] The distance can be determined as a function of a height, i.e., a line intensity, of precisely one or more characteristic, particularly anode material-specific, spectral lines in the spectral profile of the detected radiation. For example, the line intensity can be determined at one or more predetermined frequencies or frequency ranges, particularly anode material-specific and thus radiation source-specific, with the distance then being determined as a function of this / these line intensities.

[0025] This determination can also be made based on assignment, whereby, for example, in a calibration process or in corresponding preliminary tests, different distances are assigned to different heights of characteristic spectral lines. It can be assumed here that different heights can be detected for different distances. Alternatively, the distance can also be determined based on triangulation. In this case, the distance from the borehole wall can be determined as a function of a predetermined or determinable angle of incidence of the emitted X-rays onto the borehole wall and a position of an intensity maximum generated by the reflected radiation in a detector surface. Corresponding triangulation methods are known to those skilled in the art. It is also described that a distance measurement can be carried out mechanically, for example using suitable measuring devices, for example a measuring mandrel, for which purpose the system can comprise such measuring devices.These can be arranged, in particular, in or on the housing. Such a distance measurement can, for example, be performed additionally and used to correct or improve the distance measurement.

[0026] The distance can also be used to correct fluorescence-based elemental analysis, particularly by taking distance-related scattering and attenuation of the radiation into account. In particular, this distance-related scattering and attenuation can be compensated or eliminated. Thus, the intensity, particularly the spectral intensity, of the detected radiation changes depending on the distance. The greater the distance, the lower the intensity. Therefore, it is possible, with a known distance, to change the intensity of the detected radiation depending on the distance. For example, the intensity can be increased more for a greater distance than for a comparatively shorter distance. The elemental analysis can then be performed based on, or depending on, the distance-dependent corrected / changed intensity.

[0027] Based on distance information, it is also possible to classify whether the evaluated radiation originates solely or primarily from the rock (which can be assumed for distances smaller than a predetermined threshold) or whether the evaluated radiation also originates, to a certain extent, from the borehole fluid (which can be assumed for distances greater than or equal to the predetermined threshold). The proposed distance measurement enables an accuracy in the range of less than 1 mm.

[0028] Distance determination can also be used to detect breakouts in the borehole and / or to create a borehole profile. For example, a location-referenced localization of breakouts in the borehole can be performed, thus determining the borehole volume.

[0029] The distance determination also makes it possible to create partial spectra and from these to form an overall spectrum for elemental analysis. For example, during a movement of the probe body in the borehole, in particular during an upward or downward movement as well as during a sideways movement, a spectrum can be determined repeatedly, in particular periodically, further in particular at a frequency of e.g. 1 / ms, wherein a distance value can be assigned to the spectrum. This spectrum can then be referred to as a partial spectrum. A resulting distance-specific spectrum can then be determined from all spectra which were generated in particular in a predetermined period of time and / or in a predetermined position range and which are assigned the same distance value or whose assigned distance values ​​do not deviate from one another by more than a predetermined amount, e.g. by suitable averaging or fusion.The resulting distance-specific spectrum, especially the intensities in the spectrum, can then be corrected for distance, as previously explained. A total resulting spectrum can then be determined from all distance-corrected spectra, e.g., by suitable averaging or fusion, and the total resulting spectrum can then be used for elemental analysis.

[0030] The determination of the specific density and / or the distance can be performed with a location reference. If the output signals are also determined with a location reference, the specific density and / or the distance can be taken into account in the elemental analysis, particularly for subsequent evaluation or off-site evaluation, e.g., in a laboratory.

[0031] Thus, the proposed borehole probe system advantageously enables accurate and reliable elemental analysis, particularly accurate and reliable elemental identification and concentration determination. By evaluating the detector output signals to determine density and / or distance, this improvement can also be achieved during continuous surveying. At the same time, safe and environmentally friendly determination is enabled. Site-referenced elemental analysis can also be performed.

[0032] It is further possible for the probe body to comprise or form at least one decentering means that ensures a decentralized arrangement of the probe body in the borehole. For example, the probe system, in particular the probe body, can comprise or form at least one spring arm that is arranged and / or configured such that a probe body introduced into a borehole is pressed against the borehole wall by the at least one spring arm and is thus arranged decentrally in the borehole.

[0033] In a further embodiment, the evaluation device is arranged in the probe body, in particular in the housing of the probe body. In this case, the evaluation takes place in the probe body. Thus, an RF borehole probe is described that comprises the probe body, the X-ray source, the detector, and the evaluation device. This advantageously results in precise and reliable signal evaluation, in particular for determining the specific density and / or the distance, since output signals from the detector device do not have to be transmitted to an evaluation device outside the probe body, thereby reducing transmission losses and thus maintaining signal quality.

[0034] In a further embodiment, the RF borehole probe system comprises at least one high-voltage source for powering the radiation source, wherein the high-voltage source is arranged in the probe body. The high-voltage source can generate operating voltages for the radiation source of up to 50 kV or even operating voltages greater than 50 kV. This advantageously eliminates the need for means to transmit the operating voltage from a voltage source outside the probe body to the radiation source in the probe body, which in turn enables simple operation of the borehole probe system.

[0035] In a further embodiment, the high-voltage source is arranged along a central longitudinal axis of the probe body closer to an upper end of the probe body than the radiation source and / or the detector and / or the evaluation device. This enables efficient cooling of the high-voltage source and, in particular, reduces the thermal load on the detector and / or the evaluation device. This is particularly the case since thermal energy generated by the radiation source and / or the high-voltage source is dissipated upwards by convection during normal operation. Overall, the operational reliability of the proposed borehole probe system is thus advantageously improved.

[0036] In a further embodiment, the RF borehole probe system comprises a storage device for storing signals, in particular the previously explained pulses registered by the detector. In particular, these signals can be stored with a time reference. This makes it possible, for example, to store which signal / pulse was detected at which time. It is also possible to store an energy level, for example in keV, of the registered signal. The storage device is also arranged in the probe body. This advantageously enables the registration of (X-ray) photons and, in particular, the signal changes triggered by them in the detector, e.g., in the form of voltage pulses. These signal changes can be assigned a timestamp, for example, which is also stored. This advantageously simplifies subsequent evaluation, for example, off-site evaluation, i.e., outside the borehole.Storing additional information has the advantage that even if the data connection is disturbed or interrupted, data can be evaluated at a later point in time and, in particular, assigned to location information.

[0037] The described storage device or a further storage device can (also) serve to store data or data sets processed by the evaluation device, wherein a further storage device can also be arranged in the probe body. For example, a spectrum or a part thereof determined by evaluating the detected signals can thus be stored. It is also possible to store the explained specific density and / or the distance. This can be done in particular with a location reference, wherein location information, for example a spatial position, in particular depth information, can be assigned to the corresponding information and can also be stored. Of course, it is also conceivable that an element is identified and / or an element concentration is determined and corresponding element information is stored.The information stored in this way can be transferred from the storage devices in the probe body to an external system, in particular via the data and / or signal interface explained.

[0038] In a further embodiment, the RF borehole probe system comprises at least one X-ray window arranged in an outer wall of the probe body. This has already been explained above. The X-ray window is made of a material transmissive to X-rays. Such a material can be, for example, but not exclusively, PP, PEEK, TPU, borosilicate, or diamond, or a combination of at least two of these materials. It is also possible for the material to be a combination of one of the listed materials with at least one other material not explicitly listed. Furthermore, the X-ray window has a hydrophobic outer surface or is coated with a hydrophobic layer. The coating can be a nanocoating.In particular, the surface can provide a lotus effect, making this outer surface only very slightly wettable by liquids. The micro- and nanoscopic architecture of the surface can be designed accordingly. This advantageously ensures that the emission of X-rays from the probe body is influenced as little as possible by liquids, which in turn improves the accuracy and reliability of elemental analysis.

[0039] Alternatively or in addition to the hydrophobic outer surface, the outer surface of the X-ray window is coated with an aerogel material. The coating with the aerogel material can, in particular, be designed such that an aerogel pad is glued or otherwise attached to the X-ray window. The coating can be up to 1 mm thick. An aerogel can refer to an open-pore, nanostructured material. In particular, a hydrophobic aerogel material can be used for the coating. It is possible for a predetermined percentage of the volume of the aerogel material, for example up to 95%, to consist of pores. The aerogel material is preferably a silicate-based material. This also advantageously results in minimal influence on the radiation emitted from the probe body.

[0040] Further alternatively or cumulatively, the X-ray window is stabilized by a support structure. The support structure can be honeycomb-like and / or comprise support webs, wherein the mechanical strength or mechanical rigidity of the X-ray window with the support structure is greater than that of the X-ray window without the support structure. The mechanical strength or mechanical rigidity of the support structure can also be greater than the remaining window material. The material of the support structure can also be transmissive to X-rays. It is possible for the support structure to be made of the same material as the remaining window material, although the support structure can have different mechanical properties than the remaining material. This advantageously results in high stability of the X-ray window and thus high operational reliability during operation of the borehole probe system.

[0041] In a further embodiment, the RF borehole probe system comprises at least one gas outlet, wherein the gas outlet is arranged and / or configured such that a gas curtain or gas cushion can be generated in front of the X-ray window by the outlet of gas from the gas outlet. The gas can, in particular, be air or an inert gas. The outlet can be arranged such that gas flows past the X-ray window during intended use / insertion of the probe into a borehole. For example, the outlet can be arranged along the central longitudinal axis of the probe body closer to a lower end of the probe body than the X-ray window. In this case, escaping gas can flow past the X-ray window due to buoyancy. This also advantageously results in radiation emitted from the probe body by the radiation source being influenced as little as possible by borehole material.

[0042] It is further possible for the borehole probe system, in particular the probe body, to have or form a retaining device that extends the time until the gas escapes from a volume of space in front of the X-ray window compared to a design without a retaining device. Such a retaining device can, for example, be designed as a structure protruding from an outer side of the probe body.

[0043] If the borehole probe system includes a gas outlet, it is possible for the proposed system to also include at least one additional pneumatic device, for example, a pump and / or a gas reservoir, which may be pneumatically connected to the gas outlet. The additional pneumatic device may also be arranged in the probe housing.

[0044] It is also possible for the borehole probe system to include a device for generating gas from the borehole fluid. This device can also be located in the probe body and fluidically connected to the gas outlet. This advantageously results in a reduction in installation space, since no gas storage is required to supply the gas outlet; instead, gas can be generated directly from the borehole fluid.

[0045] In a further embodiment, the RF borehole probe system, in particular the probe body, comprises or forms at least one brush element for cleaning the borehole wall. Such a brush element can be used, in particular, to scrape or remove the so-called filter cake and advantageously enables more reliable and accurate elemental analysis of the rock, since the borehole material does not influence signal generation or influences it to a lesser extent. This also applies in particular to electrical, acoustic, or optical measurements of the rock.

[0046] In a further embodiment, the at least one brush element is arranged so that it can move relative to the probe body. For example, the brush element can be movably mounted on / in the probe body. It is possible for the brush element to be a driven brush element, for example, a rotating or linearly movable brush element. A corresponding drive device can be part of the borehole probe system and, in particular, be arranged in the probe body. Alternatively, the brush element is arranged stationary relative to the probe body. In this case, it can, for example, be arranged mechanically rigidly on the housing.

[0047] Alternatively or cumulatively, the at least one brush element is arranged along a central longitudinal axis of the probe body closer to an upper end or closer to a lower end of the probe body than an X-ray window in the probe body. Preferably, the brush element is arranged at the lower end of the probe body. This advantageously results in reliable removal of the filter cake before the X-ray window is moved upwards or downwards past the thus cleaned area of ​​the borehole wall, whereby the radiation emitted from the probe body is influenced as little as possible by the filter cake.

[0048] In a further embodiment, the RF borehole probe system comprises at least one light source and at least one light detector for hyperspectral material analysis. The light source can, in particular, be an infrared light source, and the light detector can be an infrared light detector. The wavelength of the infrared radiation can be in the range from 400 nm to 2000 nm. In this case, the evaluation device or another evaluation device of the borehole probe system can be designed for hyperspectral material analysis. This allows mineral analysis to be performed in addition to the RF-based elemental analysis. It is conceivable that the light generated by the light source is emitted through a window in the probe body that is different from the X-ray window. This window can, in particular, be an acrylic glass window and can be arranged closer to the lower end of the probe body than the X-ray window.Alternatively or cumulatively, the borehole probe system comprises at least one monochromatic radiation source and at least one detector for the scattered monochromatic radiation for Raman spectroscopic material analysis. In this case, the evaluation device or another evaluation device of the borehole probe system can be designed for Raman spectroscopic material analysis. It is conceivable that the radiation generated by the monochromatic radiation source is emitted through a window in the probe body that is different from the X-ray window.

[0049] Further alternatively or cumulatively, the borehole probe system comprises at least one optical radiation source that emits radiation with wavelengths of the hyperspectral spectrum, preferably with a wavelength from a spectrum of 350 to 800 nm, and at least one detector for the scattered radiation generated by the optical radiation source for material analysis based on optical fluorescence. The spectral resolution can be in the range of nm, e.g., in the range of 3 nm to 10 nm. In this embodiment, the evaluation device or a further evaluation device of the borehole probe system can be designed for material analysis based on optical fluorescence. It is conceivable that the radiation generated by the optical radiation source is emitted through a window in the probe body that is different from the X-ray radiation window.

[0050] The output signals generated by the at least one detector explained and / or the information generated by an evaluation device through material analysis can be stored in the aforementioned storage device or in a further storage device of the borehole probe system, in particular in a location- and / or time-referenced manner, e.g. in order to enable an evaluation off-site, e.g. in the laboratory.

[0051] It is also possible that the information generated by the explained material analysis and the elemental information determined by the elemental analysis based on the explained fluorescence and / or scattered radiation are stored in an associated manner.

[0052] Furthermore, the proposed borehole probe system can comprise at least one fan, which can be arranged in particular in the probe body. The fan can be arranged below or above a circuit board, with the evaluation device being arranged on the circuit board.

[0053] Furthermore, it is possible for the borehole probe system to comprise or form a cooling container, which can be arranged in particular in the probe body. This cooling container can be arranged in particular at a lower end of the probe body. The cooling container serves to hold a cooling material, for example ice. Furthermore, the cooling container can be part of a cooling system of the borehole probe system, in particular of the probe body. The cooling system can comprise at least one cooling finger, which is, for example, thermally connected to the cooling container, in particular to the cooling material in the cooling container. The cooling finger can serve to cool the air in the probe body. This allows the borehole probe system to be used even at high ambient temperatures and enables reliable and precise material analysis.

[0054] Furthermore, it is possible for the borehole probe system to comprise at least one fan, which can in particular be arranged in the probe body. The at least one fan is arranged and / or configured such that a carrier board and components arranged thereon, e.g., the evaluation device and / or the storage device, can be cooled by an air flow generated by the fan. In particular, one or more fans can be arranged and / or configured such that a circular air flow can be generated around the carrier board, i.e., also above and below the carrier board.

[0055] In a further embodiment, the borehole probe system comprises a water sensor for detecting the submerged state of the probe body. This water sensor can, for example, generate a first output signal when the probe body is underwater and another output signal when the probe body is not underwater. If the first output signal is generated, a gas outlet from the previously described outlet opening can be activated, for example. An evaluation can also be adapted to an underwater state.

[0056] This advantageously results in more precise and reliable material analysis when using the borehole probe system underwater. It is possible for all components in the probe housing to be arranged in a predetermined spatial relationship to one another, which can then be taken into account during evaluation, particularly during element and mineral analysis.

[0057] A method for operating an RF borehole probe system according to one of the embodiments described in this disclosure is proposed. Depending on the output signals generated by the detector, a specific density of the irradiated material and / or a distance between the probe body and a borehole wall is determined. This and corresponding technical advantages have already been explained above. Of course, in addition to determining the specific density and / or the distance, an elemental analysis, in particular the described element identification and concentration determination, can also be performed depending on the output signals generated by the detector.

[0058] In a preferred embodiment, an elemental analysis is performed taking into account or depending on the specific density and / or distance. As previously explained, the specific density and / or distance can affect the spectral profile of the radiation received by the detector. If the specific density and / or distance are known, the spectral profile can be corrected, which in turn enables a more accurate and reliable elemental analysis.

[0059] In a further embodiment, output signals from the detector are stored, particularly in a time-referenced manner. This and the corresponding technical advantages have already been explained above.

[0060] In a further embodiment, radiation is generated by a radiation source of the borehole probe system that is different from the X-ray source. This radiation is emitted. The radiation can, as previously explained, be infrared radiation, monochromatic radiation, or optical radiation. The scattered radiation can be detected, and a material analysis can be performed based on the detected radiation. This and corresponding advantages have already been explained above. The invention will be explained in more detail using exemplary embodiments. The figures show:

[0061] Fig. 1 is a schematic longitudinal section through a borehole probe system according to the invention,

[0062] Fig. 2 shows a schematic longitudinal section through a borehole probe system according to the invention in a further embodiment,

[0063] Fig. 3 shows a schematic cross-section through a probe body in the area of ​​the X-ray source,

[0064] Fig. 4 shows a further schematic cross-section through a probe body in the area of ​​the X-ray source,

[0065] Fig. 5 shows a schematic cross-section through a probe holder,

[0066] Fig. 6 is a perspective view of a brush element,

[0067] Fig. 7 shows a further schematic longitudinal section through a probe body in the area of ​​an X-ray window,

[0068] Fig. 8 is a perspective view of an X-ray window,

[0069] Fig. 9 is a schematic block diagram of a borehole probe system according to the invention in a further embodiment and

[0070] Fig. 10 is a schematic flow diagram of a method according to the invention for operating a borehole probe system according to the invention.

[0071] In the following, like reference numerals designate elements with the same or similar technical features. Fig. 1 shows a schematic longitudinal section through a probe body 2 of an RF borehole probe system 1 according to the invention. The probe body 2 comprises a probe cladding tube 3 and an X-ray window 19, which is arranged in the probe cladding tube 3 and allows the transmission of X-ray radiation from the interior of the probe cladding tube 3 into the environment, as well as the transmission of X-ray and / or scattered radiation from the environment into the interior of the probe cladding tube 3.The borehole probe system 1 further comprises an X-ray source 4, which is arranged in the probe body 2, in particular the probe cladding tube 3, and a detector 5, which is also arranged in the probe body 2 and is designed to detect fluorescence radiation excited by emitted X-rays and / or X-rays scattered by the environment (scattered radiation), wherein the emitted radiation is generated by the X-ray source 4. In other words, the X-ray source 4 generates the X-rays and emits them into the environment of the probe body 2, in particular into a borehole fluid 6 and into the drilled rock 7 (see Fig. 3). In a dry borehole, the radiation is emitted into the air in the borehole. In the borehole fluid 6 orFluorescence radiation is then excited in the air and / or rock 7, and / or the emitted X-rays are scattered and radiated back to the probe body 3, where this radiation is then detected by the detector 5. The borehole probe system 1 further comprises an evaluation device 8, which is also arranged in the probe body 2. Also shown is a storage device 9, which is also arranged in the probe body 3 and is connected to the evaluation device 8 for data transmission.

[0072] Furthermore, the borehole probe system comprises a high-voltage source 10, which generates or provides an operating voltage for the X-ray source 4, which can be designed in particular as an X-ray tube, preferably as a molybdenum X-ray tube.

[0073] The borehole probe system also comprises brush elements 11 which are arranged on an outer side of the probe casing tube 3 and serve to clean the borehole wall 12 (see Fig. 3).

[0074] Fig. 1 shows a lower end 13 and an upper end 14 of the probe body 2, the upper end 14 being the end of the probe body 2 closer to the surface when the probe body 2 is used as intended in the borehole 15 (see, for example, Fig. 9). At the upper end 14 of the probe body 2, an interface 16 is arranged for the mechanical attachment of a holding cable 17 (see also Fig. 9) and for establishing a signal connection with an external system, e.g., for connecting a so-called logging cable. It is possible for the holding cable 17 to have electrical wires suitable for signal transmission, whereby the holding cable 17 forms the aforementioned logging cable. In Fig. 1 it is shown that the X-ray source 10 is arranged along a central longitudinal axis of the probe body 2 closer to the upper end 14 of the probe body a2 than the radiation source 4, the detector 5 and the evaluation device 8.

[0075] The evaluation device 8, which may comprise or be designed as a microcontroller or an integrated circuit, can evaluate the output signals generated by the detector 5. The evaluation can, in particular, determine a spectrum of the radiation received by the detector 5. For this purpose, the evaluation device 8 can comprise a multi-channel analyzer. Furthermore, the evaluation device 8 can perform an elemental analysis of the irradiated material, in particular based on the spectrum and its properties. In particular, the evaluation device 8 can identify an element and determine its concentration in the irradiated material.

[0076] Additionally, the evaluation device 8 is designed to determine the specific density of the irradiated material. Alternatively or additionally, the evaluation device 8 is designed to determine the distance between the probe body 2 and the borehole wall 12. The explained elemental analysis can be carried out as a function of the specific density determined by the evaluation device 8 and / or as a function of the distance determined by the evaluation device 8. The storage device 9 serves to store the signals registered by the detector 5, in particular in a time-referenced manner. The storage device 9 or a further storage device (not shown) can also serve to store data or data sets already processed by the evaluation device 8.

[0077] Fig. 2 shows a schematic longitudinal section through a probe body 2 in a further embodiment. In contrast to the embodiment shown in Fig. 1, the borehole probe system 1, in particular the probe body 2, comprises spring elements 18 for decentering the probe body 2 in a borehole 15. In the embodiment shown in Fig. 2, the spring elements 18 are designed as arc spring elements, with the two ends of a spring element 18 being fastened to the outside of the probe cladding tube 3. Furthermore, the arc spring elements 18 protrude from the outside. When inserted into a borehole 15 (see Fig. 9), the spring elements 18 press the probe body 2 against the borehole wall 12. This advantageously ensures that as little borehole fluid 6 as possible is arranged between the X-ray window 19 and the borehole wall 12.For this purpose, the spring elements 18 are arranged on a partial area of ​​the outside of the probe cladding tube 3, which is opposite the area with the X-ray radiation window 19.

[0078] Fig. 3 shows a schematic cross-section through a partial region of the probe body 2. It depicts an X-ray tube 20 that emits X-rays through a slit diaphragm 21 and through an X-ray window 19 out of the probe body 2. A primary beam path 25 of emitted X-rays is depicted by a dashed line. Also depicted is a detector 4 and a detection region of the detector 4, delineated by a dashed line. This detector receives radiation entering the probe body 2 from the outside through the X-ray window 19, in particular the fluorescence and / or scattered radiation that is excited in the irradiated material by the X-rays generated by the radiation source 5.

[0079] Also shown are the drilled rock 7 and a borehole fluid 6, which is arranged between the probe body 2 and the borehole wall 12 formed by the drilled rock 7. Also shown is a shield plate 22, which is arranged between the X-ray tube 20 and the detector 4 and prevents radiation emitted by the X-ray tube 20 from being received by the detector 4. It is possible for the X-ray tube 20 and the detector 4 to be offset from one another along a transverse axis of the probe body 2, which can be oriented, for example, perpendicular to the plane of the drawing. Thus, detection areas can also be offset from one another along this transverse axis.

[0080] Fig. 4 shows a schematic cross-section through a probe body 2 in a further embodiment. Again shown is the X-ray tube 20, which can be designed, for example, as a side window tube. An anode of the X-ray tube can be connected to a reference or ground potential, which can be, for example, the potential of the probe cladding tube 3. A cathode can be connected to a high-voltage source 10. Also shown is an interface 23 for controlling a high-voltage source 10, which can provide a fiber optic cable connection and a connection for electrically supplying the high-voltage source 10. This interface 23 is connected to the high-voltage source 10 via a cable duct 24. A carrier board of the interface 23 can also be arranged in the cable duct 24. Also shown is the slit diaphragm 21, which can be made, for example, from molybdenum.Schematically shown is a beam path 25 of X-rays generated by the X-ray tube 20. Also shown is a mica tube 26, in which the X-ray tube 20 is arranged and which is completely encapsulated for electrical insulation.

[0081] Fig. 5 shows a schematic cross-section through an interface 16, which can be arranged at the upper end of a probe body 2 (see, for example, Fig. 1). The interface 16 comprises a 4-pin connection device 27. This is arranged in a through-opening 28 formed by the interface 16. It is further shown that the 4-pin connection device 27 is connected to an external thread element 31 via a sealing ring 29 and a spacer 30. The external thread element 31 can be screwed into an internal thread of the interface 16 arranged in the through-opening 28. Also shown are external thread sections 32, 33 of the interface 16, wherein a first external thread 32 is used to connect a holding and logging cable 17 (see Fig. 9) and a second external thread 33 is used to screw the interface 16 into the probe body 2. The interface 16 can be made of titanium.

[0082] Fig. 6 shows a perspective view of a brush element 11. This brush element 11 has grooves 34 or notches on an outer surface, the central axes of which are oriented obliquely to a central longitudinal axis of the brush element 11. If this brush element 11 slides along a borehole wall 12 (see, for example, Fig. 3), material scraped off the borehole wall 12 can enter the grooves 34 and be transported along the grooves 34.

[0083] Fig. 7 shows a schematic cross-section through a portion of the probe body 2 in the region of the X-ray window 19. It depicts a gas outlet element 35 that is fluidically connected to a gas reservoir 36 arranged in the probe body 2. The gas outlet 35 is arranged, purely by way of example, on an outer side of the probe cladding tube 3. If the gas outlet 35 is fluidically connected to the gas reservoir 36 and supplied with gas, the gas outlet 35 generates a gas curtain or gas cushion in front of the X-ray window 19, in particular in front of an outer side of the X-ray window 19.

[0084] Alternatively or cumulatively, to provide such a gas curtain or gas cushion, the X-ray window 19 can have or form a hydrophobic outer surface or be coated with a hydrophobic layer. Further alternatively or cumulatively, the X-ray window 19, in particular an outer surface, can be coated with an aerogel material.

[0085] Fig. 8 shows a perspective view of an X-ray window 19 made of a material transmissive to X-rays. Screws 37 for mechanically connecting the X-ray window 19 to the probe body 2 are shown. Also schematically shown are support grid elements 38, which improve the mechanical stability of the X-ray window 19.

[0086] Fig. 9 shows a schematic block diagram of an RF borehole probe system 1 according to the invention in a further embodiment. Shown is a probe body 2, which can comprise an X-ray source 4 (not shown) and a detector 5 (likewise not shown) (see Fig. 1). The probe body 2, in particular the components arranged in the probe body 2, is connected to an external system 39 via a logging cable 17, which simultaneously forms a holding cable of the probe body 2. This external system 39 comprises, for example, a drive device for transmitting a tensile force to the holding and logging cable 17. Furthermore, the external system can comprise an evaluation device 8, which is connected for data and / or signal purposes via the holding and logging cable 17 to, for example, the detector 5 of the probe body 2.This evaluation device 8 can be designed for the previously explained element analysis as well as for determining the specific density and / or for determining the distance between the probe body 2 and the borehole wall 11.

[0087] Fig. 11 shows a schematic flow diagram of a method according to the invention for operating an RF borehole probe system 1 according to one of the embodiments described in this disclosure. In a first step S1, X-ray radiation is generated by an X-ray source 4 (see, for example, Fig. 1) and emitted from the probe body 2. In a second step S2, the fluorescence radiation emitted by this radiation and / or the scattered radiation explained is detected by a detector 5. In a third step S3, the output signals generated by the detector 5 upon receipt of this radiation are evaluated by an evaluation device 8. In the third step S3, the evaluation device 8 also determines a specific density of the irradiated material. Alternatively or cumulatively, a distance between the probe body 2 and the borehole wall 12 is determined.Depending on the specific density and / or distance, an elemental analysis of the irradiated material is then performed by the evaluation device or a higher-level system. Output signals generated by the detector can be stored simultaneously with or after the evaluation, particularly in a time-referenced manner. Furthermore, information generated by the evaluation can also be stored.

[0088] List of reference symbols

[0089] 1 RF borehole probe system

[0090] 2 probe bodies

[0091] 3 Probe cladding tube

[0092] 4 X-ray source

[0093] 5 Detector

[0094] 6 Wellbore fluid

[0095] 7 rock

[0096] 8 Evaluation device

[0097] 9 Storage device

[0098] 10 High voltage source

[0099] 11 Brush element

[0100] 12 borehole wall

[0101] 13 lower end

[0102] 14 upper end

[0103] 15 borehole

[0104] 16 Interface

[0105] 17 Holding and logging cables

[0106] 18 spring element

[0107] 19 X-ray windows

[0108] 20 X-ray tubes

[0109] 21 slit aperture

[0110] 22 Shield plate

[0111] 23 Interface

[0112] 24 cable duct

[0113] 25 Exit

[0114] 26 mica tubes

[0115] 27 Connection device

[0116] 28 passage opening

[0117] 29 Sealing element

[0118] 30 spacer element

[0119] 31 external thread element

[0120] 32 external thread

[0121] 33 External thread Groove Gas outlet Gas storage Screw Support bar External system First step Second step Third step

Claims

Patent claims 1. RF borehole probe system comprising at least - a probe body (2), - at least one X-ray source (4) arranged in the probe body (2), - a detector (5) for fluorescence and scattered radiation, the detector (5) being arranged in the probe body (2), - an evaluation device (8) for evaluating the output signals generated by the detector (5), wherein the evaluation device (8) is designed for elemental analysis of the irradiated material, characterized in that the evaluation device (8) is additionally designed for determining the specific density of the irradiated material and / or for determining the distance between the probe body (2) and a borehole wall (12).

2. RF borehole probe system according to claim 1, characterized in that the evaluation device (8) is arranged in the probe body (2).

3. RF borehole probe system according to one of the preceding claims, characterized in that the RF borehole probe system (1) comprises at least one high-voltage source (10) for supplying energy to the X-ray source (4), wherein the high-voltage source (10) is arranged in the probe body (2).

4. RF borehole probe system according to claim 3, characterized in that the high voltage source (10) is arranged along a central longitudinal axis of the probe body (2) closer to an upper end (14) of the probe body (2) than the X-ray source (4) and / or the detector (5) and / or the evaluation device (8).

5. RF borehole probe system according to one of the preceding claims, characterized in that the RF borehole probe system (1) comprises a storage device (9) for storing the signals registered by the detector (5), in particular of time-referenced signals, wherein the storage device (9) is arranged in the probe body (2). RF borehole probe system according to one of the preceding claims, characterized in that the RF borehole probe system (1) comprises at least one X-ray window (19) which is arranged in an outer wall of the probe body (2), wherein the X-ray window (19) - Is made of a material transmissive to X-rays and / or - has a hydrophobic outer surface or is coated with a hydrophobic layer and / or - is coated with an aerogel material and / or - is stabilized by a support structure. RF borehole probe system according to one of the preceding claims, characterized in that the RF borehole probe system (1) comprises at least one gas outlet (35), the arrangement of which, when gas is supplied, creates a gas curtain or a gas cushion in front of the X-ray window (19). RF borehole probe system according to one of the preceding claims, characterized in that the RF borehole probe system (1) has or forms at least one brush element for cleaning the borehole wall. RF borehole probe system according to one of the preceding claims, characterized in that the at least one brush element (11) - is arranged movable or stationary relative to the probe body (2) and / or - is arranged along a central longitudinal axis of the probe body (2) closer to an upper end (14) or closer to a lower end (13) of the probe body (2) than an X-ray window (19) in the probe body (2). RF borehole probe system according to one of the preceding claims, characterized in that the RF borehole probe system (1) - at least one light source and at least one light detector for hyperspectral material analysis and / or - at least one monochromatic radiation source and at least one detector for the scattered monochromatic radiation for Raman spectroscopic material analysis - comprises at least one optical radiation source and at least one detector for the scattered monochromatic radiation for material analysis based on optical fluorescence. RF borehole probe system according to one of the preceding claims, characterized in that the RF borehole probe system (1) comprises a water sensor for detecting a state of the probe body (2) in water. Method for operating an RF borehole probe system (1) according to one of claims 1 to 11, characterized in that a specific density of the irradiated material and / or a distance between the probe body (2) and a borehole wall (12) is determined as a function of the output signals generated by the detector (5). Method according to claim 12, characterized in that an elemental analysis is carried out taking into account the specific density and / or the distance.Method according to one of claims 12 to 13, characterized in that output signals of the detector (5), in particular time-referenced output signals, are stored. Method according to one of claims 12 to 14, characterized in that infrared radiation is generated and emitted, wherein scattered infrared radiation is detected, and a mineral analysis is performed depending on the detected radiation, and / or wherein monochromatic radiation is generated and emitted, wherein the scattered monochromatic radiation is detected, and a material analysis is performed depending on the detected radiation.

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