Neutron tube anode current regulation method and device based on element logging instrument

Abstract

The application discloses a neutron tube anode current regulation method and device based on an element logging instrument. The method comprises the following steps: in the preheating stage, the filament current is regulated to a first filament current value to drive the neutron tube anode current to rise; after detecting that the neutron tube anode current rises to a preset anode current value, the method enters the falling stage, in the falling stage, the filament current is regulated to a second filament current value to drive the neutron tube anode current to fall; after detecting that the neutron tube anode current is less than an anode current expected stable value, the method enters the coarse adjustment stage, in the coarse adjustment stage, the filament current is adjusted by a coarse adjustment amplitude; after detecting that the neutron tube anode current meets the coarse adjustment stable condition, the method enters the fine adjustment stage, in the fine adjustment stage, the filament current is adjusted by a fine adjustment amplitude, and the fine adjustment amplitude is less than the coarse adjustment amplitude. The scheme can realize dynamic stability of the anode current around the anode current expected stable value, and guarantee the precision of the element logging instrument.

Description

Technical Field

[0001] This invention relates to the field of exploration technology, specifically to a method and device for controlling the anode current of a neutron tube based on an element logging tool. Background Technology

[0002] Gamma-ray spectrum-based elemental logging tools are logging instruments that generate high-energy pulsed neutrons using a controllable neutron source and analyze the secondary gamma-ray spectrum excited by the pulsed neutrons to obtain the elemental content of the formation.

[0003] The neutron tube is an important component of an elemental logging instrument. Under the control of relevant control panels, the neutron tube generates neutrons through deuterium release, deuterium ionization, deuterium ion acceleration, and bombardment of a tritium target. The anodic current value of the neutron tube reflects the deuterium ionization effect, thus affecting the neutron yield.

[0004] When the neutron tube anode current cannot be kept stable, the neutron yield of the neutron tube will fluctuate abnormally. Since the neutron yield is related to the intensity of nuclear reactions of formation elements, when the neutron yield cannot be kept stable, the target energy spectrum measured by the elemental logging tool will be distorted, failing to reflect the true formation element content information. Therefore, maintaining the stability of the neutron tube anode current is of great significance. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a method and apparatus for controlling the anode current of a neutron tube based on an element logging tool to overcome or at least partially solve the above problems.

[0006] According to one aspect of the present invention, a method for controlling the anode current of a neutron tube based on an elemental logging tool is provided, the method comprising:

[0007] During the preheating stage, the filament current is adjusted to the first filament current value to drive the neutron tube anode current to rise.

[0008] Once the neutron tube anode current is detected to rise to the preset anode current value, it enters the fallback phase. During the fallback phase, the filament current is adjusted to the second filament current value to drive the neutron tube anode current to fall back.

[0009] Once the neutron tube anode current is detected to be less than the expected stable value of the anode current, the coarse adjustment stage is entered. In the coarse adjustment stage, the filament current is differentially adjusted by the coarse adjustment amplitude.

[0010] Once the neutron tube anode current is detected to meet the coarse adjustment stabilization condition, the fine adjustment stage begins. In the fine adjustment stage, the filament current is differentially adjusted using a fine adjustment amplitude; wherein, the fine adjustment amplitude is smaller than the coarse adjustment amplitude.

[0011] In one optional implementation, the step of differentially adjusting the filament current using a coarse adjustment amplitude during the coarse adjustment stage further includes:

[0012] During the coarse adjustment phase, the anode current of the neutron tube is periodically monitored.

[0013] Whenever a value of the neutron tube anode current is detected, the target coarse tuning interval corresponding to that value is determined.

[0014] Determine the target coarse adjustment amplitude range and / or target coarse adjustment amplitude gradient for the target coarse adjustment sub-interval matching, and adjust the filament current using the target coarse adjustment amplitude range and / or target coarse adjustment amplitude gradient.

[0015] In an optional implementation, the method further includes: whenever a detected value of the neutron tube anode current is detected, determining the trend of change corresponding to that detected value;

[0016] Determine the target coarse adjustment magnitude gradient that matches the target coarse adjustment sub-interval and its corresponding trend of change.

[0017] In an optional implementation, the method further includes: determining the target detection frequency for target coarse tone sub-interval matching;

[0018] The periodic detection of the neutron tube anode current during the coarse adjustment phase further includes: detecting the neutron tube anode current using a target detection frequency.

[0019] In one optional implementation, the differential adjustment of the filament current using a fine-tuning amplitude during the fine-tuning stage further includes:

[0020] During the fine-tuning phase, the anode current of the neutron tube is periodically monitored.

[0021] Whenever a value of the neutron tube anode current is detected, the difference between the detected value and the expected stable value of the anode current is calculated.

[0022] Determine the target fine-tuning difference range corresponding to the difference;

[0023] Determine the target fine-tuning amplitude gradient and / or target fine-tuning frequency to match the target fine-tuning difference range, and adjust the filament current using the target fine-tuning amplitude gradient and / or target fine-tuning frequency.

[0024] In an optional implementation, after adjusting the filament current using the target fine-tuning amplitude gradient and / or target fine-tuning frequency, the method further includes:

[0025] Determine whether the adjusted difference is less than the original difference;

[0026] If not, a new fine-tuning gradient is generated based on the target fine-tuning gradient, and the filament current is adjusted using the new fine-tuning gradient.

[0027] In one optional implementation, after adjusting the filament current to a first filament current value during the preheating stage, the method further includes: generating an alarm message if the preheating stage duration reaches a preset duration threshold and the neutron tube anode current does not reach a preset anode current value.

[0028] According to another aspect of the present invention, a neutron tube anode current control device based on an element logging tool is provided, the device comprising:

[0029] The preheating module is used to adjust the filament current to the first filament current value during the preheating stage in order to drive the neutron tube anode current to rise.

[0030] The fallback processing module is used to enter the fallback stage after the detected neutron tube anode current rises to a preset anode current value. During the fallback stage, the filament current is adjusted to the second filament current value to drive the neutron tube anode current to fall back.

[0031] The coarse adjustment module is used to enter the coarse adjustment stage after the detected neutron tube anode current is less than the expected stable value of the anode current. In the coarse adjustment stage, the filament current is differentially adjusted by the coarse adjustment amplitude.

[0032] The fine-tuning module is used to enter the fine-tuning stage after the detected neutron tube anode current meets the coarse-tuning stability condition. In the fine-tuning stage, the filament current is differentially adjusted using the fine-tuning amplitude; wherein, the fine-tuning amplitude is smaller than the coarse-tuning amplitude.

[0033] In one alternative implementation, the coarse adjustment processing module is used to: periodically detect the anode current of the neutron tube during the coarse adjustment phase;

[0034] Whenever a value of the neutron tube anode current is detected, the target coarse tuning interval corresponding to that value is determined.

[0035] Determine the target coarse adjustment amplitude range and / or target coarse adjustment amplitude gradient for the target coarse adjustment sub-interval matching, and adjust the filament current using the target coarse adjustment amplitude range and / or target coarse adjustment amplitude gradient.

[0036] In one optional implementation, the coarse adjustment processing module is used to: whenever a detected value of the neutron tube anode current is detected, determine the trend of change corresponding to that detected value;

[0037] Determine the target coarse adjustment magnitude gradient that matches the target coarse adjustment sub-interval and its corresponding trend of change.

[0038] In one alternative implementation, the coarse adjustment processing module is used to: determine the target detection frequency for matching the target coarse adjustment sub-interval; and use the target detection frequency to detect the neutron tube anode current.

[0039] In one alternative implementation, the fine-tuning processing module is used to: periodically detect the anode current of the neutron tube during the fine-tuning phase;

[0040] Whenever a value of the neutron tube anode current is detected, the difference between the detected value and the expected stable value of the anode current is calculated.

[0041] Determine the target fine-tuning difference range corresponding to the difference;

[0042] Determine the target fine-tuning amplitude gradient and / or target fine-tuning frequency to match the target fine-tuning difference range, and adjust the filament current using the target fine-tuning amplitude gradient and / or target fine-tuning frequency.

[0043] In one optional implementation, the fine-tuning processing module is used to: after adjusting the filament current using the target fine-tuning amplitude gradient and / or target fine-tuning frequency, determine whether the difference after adjustment is less than the difference before adjustment;

[0044] If not, a new fine-tuning gradient is generated based on the target fine-tuning gradient, and the filament current is adjusted using the new fine-tuning gradient.

[0045] In one optional implementation, the preheating module is used to: after adjusting the filament current to a first filament current value during the preheating stage, if the preheating stage duration reaches a preset duration threshold and the neutron tube anode current does not reach a preset anode current value, then generate an alarm message.

[0046] According to another aspect of the present invention, a computing device is provided, comprising: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other via the communication bus;

[0047] The memory is used to store at least one executable instruction, which causes the processor to perform the operation corresponding to the above-described neutron tube anode current control method based on the element logging tool.

[0048] According to another aspect of the present invention, a computer storage medium is provided, wherein at least one executable instruction is stored therein, the executable instruction causing a processor to perform the operation corresponding to the above-described neutron tube anode current control method based on an element logging tool.

[0049] The neutron tube anode current control method and apparatus based on an elemental logging tool disclosed in this invention divides the control of the neutron tube anode current into a preheating stage, a settling stage, a coarse adjustment stage, and a fine adjustment stage. In the coarse adjustment stage, a larger adjustment range can shorten the stabilization time of the anode current. In the fine adjustment stage, a smaller adjustment range can ensure the stability and accuracy of the anode current. The coordination of the coarse and fine adjustment stages enables dynamic stabilization of the anode current near its expected stable value, ensuring the accuracy of the elemental logging tool. The above description is merely an overview of the technical solution of this invention. To better understand the technical means of this invention and to implement it according to the description, and to make the above and other objects, features, and advantages of this invention more apparent, specific embodiments of this invention are described below. Attached Figure Description

[0050] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0051] Figure 1 This diagram illustrates the structure of an element logging instrument provided in an embodiment of the present invention.

[0052] Figure 2 A schematic diagram of the driving and feedback process of a neutron tube provided in an embodiment of the present invention is shown;

[0053] Figure 3 A schematic flowchart of a neutron tube anode current control method based on an element logging tool provided by an embodiment of the present invention is shown.

[0054] Figure 4 A flowchart illustrating a method for adjusting the difference in the coarse adjustment stage according to an embodiment of the present invention is shown.

[0055] Figure 5 This diagram illustrates a process for determining the upper limit and / or lower limit of coarse adjustment amplitude according to an embodiment of the present invention.

[0056] Figure 6 A flowchart illustrating a difference adjustment method in the fine-tuning stage provided by an embodiment of the present invention is shown.

[0057] Figure 7 This diagram illustrates the variation of anode current and filament current in a neutron tube according to an embodiment of the present invention.

[0058] Figure 8 This diagram illustrates a structural schematic of a neutron tube anode current control device based on an element logging instrument, according to an embodiment of the present invention.

[0059] Figure 9 A schematic diagram of the structure of a computing device provided in an embodiment of the present invention is shown. Detailed Implementation

[0060] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0061] The neutron tube anode current control method and device based on element logging tool provided by this invention are mainly used in element logging tools based on gamma energy spectrum. This type of element logging tool uses a controllable neutron source, avoiding the safety hazards that may be caused by traditional chemical sources, and has the advantages of safety, high efficiency and controllable yield.

[0062] The specific structure of the elemental logging tool based on gamma spectroscopy can be as follows: Figure 1 As shown. From Figure 1 As can be seen, the elemental logging tool includes a main control unit, a detector unit (including a PMT photomultiplier tube and a BGO crystal), connectors, a neutron generator (also known as a neutron tube, which includes a source port), and a source control unit, etc. Combined with... Figure 2 As can be seen, the surface system communicates with the elemental logging tool and the power conversion section (QA) via EDIB communication. The QA communicates with the main control section (EA) via a communication bus. The main control section mainly includes the main control board, and may also include a preamplifier board and a low-voltage power supply module (not shown in the figure). The main control section is mainly used for overall instrument communication, spectrum acquisition and processing, issuing parameter adjustment commands to the source control section, generating neutron excitation timing, etc. The main control section communicates with the source control section (AA) via RS485 communication. The source control section mainly includes the source control board, filament drive board, target pressure drive board, pulse drive board, feedback measurement board, and various power supply modules (target pressure power supply board, high-voltage power supply board, filament power supply board, etc.). The source control section is the command execution end, mainly responsible for driving the neutron tube, detecting neutron tube parameters, and stabilizing production, etc. The neutron tube mainly consists of a memory, an ion source, a voltage multiplier, and a target. The excitation and yield regulation of the neutron source are mainly coordinated by the main control section and the source control section. The excitation process of the neutron source mainly includes four processes: deuterium release, deuterium ionization, deuterium ion acceleration, and neutron generation by bombarding the tritium target. During the driving process, the feedback measurement board collects the feedback data of the neutron tube, which is then regulated by the source control board to maintain a stable neutron yield.

[0063] Several operating parameters of a neutron tube affect neutron yield. These parameters primarily include thermionic current, anode high voltage, and target high voltage. Thermionic current and anode high voltage mainly influence neutron yield through the neutron tube's anode current. The relationship between the neutron tube's anode current and neutron yield exhibits an irregular functional relationship, making stable control of the neutron yield quite challenging. The neutron tube's anode current is a crucial indicator of deuterium ionization effectiveness, directly proportional to the internal pressure. If the anode current cannot remain stable, it reflects that the deuterium ionization process is affected, causing abnormal fluctuations in the neutron yield. In extreme cases, these fluctuations may not only prevent normal neutron production but may also damage the neutron tube due to excessive pressure.

[0064] In view of this, the present invention provides a neutron tube anode current control scheme, mainly targeting the control of the neutron tube anode current in an elemental logging tool based on gamma spectroscopy, so as to keep the neutron tube anode current relatively stable, thereby maintaining the stability of neutron production and ensuring the logging accuracy of the elemental logging tool. The following embodiments illustrate in detail the specific implementation process of the neutron tube anode current control scheme of the present invention.

[0065] Figure 3 The diagram shows a flowchart of a neutron tube anode current control method based on an element logging tool provided by an embodiment of the present invention.

[0066] In the specific implementation process, the neutron tube needs to heat the filament (such as a tungsten filament) in the gas storage chamber to release deuterium gas. Heating the filament requires controlling the filament current, thus deuterium gas release is related to the filament current. The deuterium gas released during the deuterium release stage is the load during the deuterium ionization stage. When the anode voltage is preset to a fixed value, the anode current value will indirectly reflect the amount of deuterium ionization. When the filament is continuously heated to the same value or when anode ionization is affected by the target electrode high voltage adjustment, the gas pressure inside the neutron tube will change, leading to changes in the neutron tube anode current. Therefore, in this embodiment of the invention, the neutron tube anode current is controlled by adjusting the filament current, thereby adjusting the deuterium gas input and achieving dynamic equilibrium. To avoid irregular and uncontrollable effects of anode voltage changes on the anode current, the anode voltage value remains fixed during the anode current control process in this embodiment of the invention; for example, the anode voltage can be fixed at 2kV. The output range of the filament current drive board in this embodiment of the invention can be 0–800mA.

[0067] In this embodiment of the invention, the adjustment process of the neutron tube anode current is divided into a preheating stage, a fallback stage, a coarse adjustment stage, and a fine adjustment stage, and different control methods are used in different stages.

[0068] like Figure 3As shown, the method specifically includes the following steps:

[0069] In step S310, during the preheating stage, the filament current is adjusted to the first filament current value to drive the neutron tube anode current to rise.

[0070] To shorten the time it takes for the gas storage chamber to reach normal operating conditions, this embodiment of the invention first preheats the filament; this preheating process is the preheating stage. During the preheating stage, the filament current is set to a first filament current value, which is a preset, relatively high, fixed current value. For example, the first filament current value can be 700mA, thus maintaining the filament current at 700mA during the preheating stage. Because the filament current is set to the first filament current value during the preheating stage, the neutron tube anode current will continuously increase, i.e., drive the neutron tube anode current to rise.

[0071] Step S320: After the neutron tube anode current is detected to rise to the preset anode current value, the fallback phase begins. During the fallback phase, the filament current is adjusted to the second filament current value to drive the neutron tube anode current to fall back.

[0072] During the rise of the neutron tube anode current, the anode current is monitored, for example, using real-time monitoring or timed monitoring. Monitoring the anode current rise process prevents potential damage to the neutron tube in case of a fault, thus improving the safety and stability of well logging.

[0073] During the rise of the neutron tube anode current, if the anode current reaches a preset anode current value, the current stage switches from the preheating stage to the fallback stage. The control method used in the fallback stage is to maintain the filament current at a second filament current value, such as 0, to reduce the neutron tube anode current value, resulting in a fallback. The preset anode current value is a fixed, pre-set current value higher than the expected stable anode current value; for example, the preset anode current value could be 200uA.

[0074] Step S330: Determine whether the neutron tube anode current is less than the expected stable value of the anode current; if yes, proceed to step S340; if no, proceed to step S320.

[0075] During the fallback phase, the neutron tube anode current is continuously monitored, and it is determined whether the neutron tube anode current is less than the expected stable value of the anode current. If so, step S340 is executed to enter the coarse adjustment phase; otherwise, the monitoring continues.

[0076] In one optional implementation, if the preheating phase duration reaches a preset duration threshold and the neutron tube anode current does not reach a preset anode current value, an alarm message is generated. In specific implementation, if the neutron tube anode current reaches the preset anode current value before the preheating phase duration reaches the preset duration threshold (e.g., 2 minutes), a fallback phase begins, and the corresponding control method is used for adjustment. If the neutron tube anode current still does not reach the preset anode current value when the preheating phase duration reaches the preset duration threshold, it indicates an anomaly, and a warning message is generated for anomaly handling. The filament current drive is stopped, and the ionization process is shut down to ensure the safety of the neutron tube. For example, if the neutron tube anode current reaches 200uA within 2 minutes of preheating, the fallback phase begins; if the current neutron tube anode current is determined to be less than 200uA when the preheating period reaches 2 minutes, a corresponding alarm message is generated, and the filament current drive is stopped, shutting down the ionization process.

[0077] Step S340: Enter the coarse adjustment stage. In the coarse adjustment stage, the filament current is differentially adjusted using the coarse adjustment amplitude.

[0078] During the neutron tube anode current decline process, the current value of the neutron tube anode current continues to be monitored. Once the neutron tube anode current falls below the expected stable value, the process switches from the decline phase to the coarse adjustment phase. Specifically, the coarse adjustment phase begins after the neutron tube anode current is detected to be below the expected stable value. The expected stable value of the anode current is a current value set in the initial state, indicating the desired dynamic stability of the anode current within this value. For example, the expected stable value could be 150µA. Therefore, the coarse adjustment phase begins when the neutron tube anode current is detected to be below 150µA. Furthermore, the adjustment method of this embodiment allows the anode current to be dynamically stabilized around 150µA.

[0079] The control method used in the coarse adjustment stage is to make differential adjustments to the filament current using a coarse adjustment amplitude. This differential adjustment is based on the difference between the current neutron tube anode current and its expected stable value, dynamically adjusting the filament current.

[0080] In an optional implementation, to further improve the adjustment accuracy of the neutron tube anode current, this implementation can employ, as follows: Figure 4 Steps S341-S345 shown are used to perform differential adjustment of the filament current during the coarse adjustment stage:

[0081] Step S341: In the coarse adjustment stage, the neutron tube anode current is detected using the target detection frequency, for any detected neutron tube anode current value.

[0082] In the coarse adjustment phase, the neutron tube anode current is periodically detected at a corresponding detection frequency. The detected value of the neutron tube anode current is the measured value of the neutron tube anode current. For any detected value, subsequent steps S342-S345 are executed. The frequency used for periodic detection is the target detection frequency, which is dynamically adjusted based on the processing results of subsequent steps.

[0083] Step S342: Determine the target coarse tone interval corresponding to the detection value.

[0084] In order to more accurately control the neutron tube anode current and to make the neutron tube anode current quickly stabilize, in this embodiment, the current value range of the neutron tube anode current in the coarse adjustment stage is divided into multiple sub-ranges. These multiple sub-ranges are the coarse adjustment sub-ranges. Thus, each coarse adjustment sub-range corresponds to an anode current value range, and each coarse adjustment sub-range has a corresponding range start point and range end point.

[0085] After a neutron tube anode current is detected in step S341, the detected value of the neutron tube anode current is compared with the start point and / or end point of each coarse adjustment interval to determine the coarse adjustment interval corresponding to the detected value of the neutron tube anode current. The corresponding coarse adjustment interval is the target coarse adjustment interval.

[0086] Alternatively, the coarse adjustment sub-intervals can be divided based on the expected stable value of the anode current. For example, the coarse adjustment sub-intervals can be divided as follows: A coarse adjustment stable sub-interval [Xa, X+a] is defined based on the expected stable value of the anode current, where X is the expected stable value of the anode current, and a can be 15uA, etc., and the sub-intervals are divided outwards from the middle of the coarse adjustment stable sub-interval. Furthermore, interval markers can be assigned to the divided coarse adjustment intervals. A specific method for dividing the coarse adjustment intervals and the interval markers are shown in Table 1 below:

[0087] Table 1

[0088]

[0089] If the expected stable value of the anode current is 150uA, the coarse adjustment sub-interval division method and interval label can be shown in Table 2 below. The coarse adjustment stable sub-interval in Table 2 is [135, 165].

[0090] Table 2

[0091]

[0092] In one optional implementation, if the detected values ​​of multiple neutron tube anode currents detected consecutively within a preset time period correspond to the same target coarse tuning interval, then the subsequent steps are executed.

[0093] Step S343: Determine the target coarse adjustment amplitude range and / or target coarse adjustment amplitude gradient for the target coarse adjustment sub-interval matching.

[0094] A mapping relationship between each coarse adjustment sub-interval and the coarse adjustment amplitude range is established in advance. The coarse adjustment amplitude range constrains the adjustment amplitude of the filament current in the corresponding coarse adjustment sub-interval. That is, the adjustment amplitude of the filament current in a certain coarse adjustment sub-interval should be within the coarse adjustment amplitude range matched by that coarse adjustment sub-interval. The coarse adjustment amplitude range matched by different coarse adjustment sub-intervals is different.

[0095] Optionally, in the mapping relationship between each coarse adjustment sub-interval and the coarse adjustment amplitude range, the coarse adjustment amplitude range specifically includes the upper limit and / or lower limit of the coarse adjustment amplitude. Specifically, a baseline value for the upper limit and lower limit of the coarse adjustment amplitude in the coarse adjustment stage can be set first, and a mapping relationship can be established between the stable coarse adjustment sub-interval and the baseline values ​​for the upper and lower limits of the coarse adjustment amplitude. Then, based on the offset between other coarse adjustment subspaces and the stable coarse adjustment sub-intervals, the upper limit and / or lower limit of the coarse adjustment amplitude mapped to other coarse adjustment sub-intervals can be quantitatively adjusted on the basis of the upper limit and / or lower limit of the coarse adjustment amplitude baseline values. In specific implementation, if the interval marker of the coarse adjustment subspace is smaller than that of the stable coarse adjustment sub-interval, the upper limit of the coarse adjustment amplitude gradually increases as the interval marker decreases; if the interval marker of the coarse adjustment subspace is larger than that of the stable coarse adjustment sub-interval, the upper limit of the coarse adjustment amplitude gradually increases as the interval marker increases.

[0096] Further optional, specifically, can be adopted Figure 5 The process shown is used to determine the upper limit and / or lower limit of the coarse adjustment range. Figure 5 Combining Tables 1 and 2, the upper limit m of the coarse adjustment range filament current is assigned as the upper limit reference value, and the lower limit m is assigned as the lower limit reference value. The range is divided based on the expected stable value of the anode current, and different flag values ​​(range flags) are assigned to each anode current range to further define the range. If the State value (range flag) = 4, then m and n remain unchanged; if the State value (range flag) is less than 4, the trend of the State value is judged. If it is on an upward trend, the upper limit m remains unchanged; otherwise, the upper limit m is increased by a fixed value. If the State value (range flag) is greater than 4, the trend of the State value is judged. If it is on a downward trend, the lower limit n remains unchanged; otherwise, the lower limit n is decreased by a fixed value. If the State offset stabilizes to 0 within a certain period (i.e., the corresponding range flag stabilizes at 4), then the upper and lower limits of the stable anode current coarse adjustment range filament current adjustment value are obtained.

[0097] After determining the target coarse tone sub-interval corresponding to the detection value in step S342, the coarse tone amplitude range that has a mapping relationship with the target coarse tone sub-interval is determined by querying the mapping relationship between each coarse tone sub-interval and the coarse tone amplitude range. This coarse tone amplitude range is the coarse tone amplitude range that matches the target coarse tone sub-interval, i.e., the target coarse tone amplitude range.

[0098] Furthermore, a mapping relationship between each coarse adjustment sub-interval and the coarse adjustment amplitude gradient can be pre-established. This coarse adjustment amplitude gradient determines the adjustment amplitude and direction of the filament current in the corresponding coarse adjustment sub-interval. The adjustment direction includes positive and negative adjustments. That is, in a certain coarse adjustment sub-interval, the adjustment amplitude and direction of the filament current should be the coarse adjustment amplitude gradient matched to that coarse adjustment sub-interval. Different coarse adjustment sub-intervals are matched with different coarse adjustment amplitude gradients.

[0099] Optionally, in the mapping relationship between each coarse adjustment sub-interval and the coarse adjustment magnitude gradient, taking the coarse adjustment stable sub-interval as the benchmark, the larger the offset of other coarse adjustment sub-intervals from the coarse adjustment stable sub-interval, the larger the absolute value of the coarse adjustment magnitude gradient matched by the coarse adjustment sub-interval. Thus, the absolute value of the coarse adjustment magnitude gradient matched by the coarse adjustment stable sub-interval is the smallest. Taking Tables 1 and 2 as examples, the absolute value of the coarse adjustment magnitude gradient matched by coarse adjustment sub-interval 4 (coarse adjustment stable sub-interval) is the smallest. The offset of coarse adjustment sub-intervals 3 and 5 from coarse adjustment sub-interval 4 is 1, so the absolute value of the coarse adjustment magnitude gradient of coarse adjustment sub-intervals 3 and 5 is greater than that of coarse adjustment sub-interval 4. Correspondingly, the absolute value of the coarse adjustment magnitude gradient of coarse adjustment sub-intervals 2 and 6 is greater than that of coarse adjustment sub-intervals 3 and 5, and the absolute value of the coarse adjustment magnitude gradient of coarse adjustment sub-intervals 1 and 7 is greater than that of coarse adjustment sub-intervals 2 and 6. Therefore, the closer to the coarse adjustment stable sub-interval, the smaller the corresponding adjustment magnitude.

[0100] After determining the target coarse tone sub-interval corresponding to the detection value in step S342, the coarse tone amplitude gradient that has a mapping relationship with the target coarse tone sub-interval is determined by querying the mapping relationship between each coarse tone sub-interval and the coarse tone amplitude gradient. This coarse tone amplitude gradient is the coarse tone amplitude gradient that matches the target coarse tone sub-interval, i.e., the target coarse tone amplitude gradient.

[0101] In one optional implementation, to further improve the precision of neutron tube anode current regulation, shorten the coarse adjustment stage, and improve regulation efficiency, this implementation determines the coarse adjustment amplitude gradient by combining the changing trend of the neutron tube anode current. In the specific implementation process, a mapping relationship between each coarse adjustment sub-interval and its changing trend is pre-established with the coarse adjustment amplitude gradient; that is, each combination of a coarse adjustment sub-interval and its changing trend corresponds to a fine-grained coarse adjustment amplitude gradient. Therefore, after determining the target coarse adjustment sub-interval corresponding to the detected value in step S332, the changing trend corresponding to that detected value is also determined. This changing trend is determined relative to the previous N detected values, and the changing trend includes both an upward trend and a downward trend. By querying the mapping relationship between each coarse adjustment sub-interval and its changing trend with the coarse adjustment amplitude gradient, the target coarse adjustment amplitude gradient matching the target coarse adjustment sub-interval and its corresponding changing trend is determined. That is, in the mapping relationship between each coarse adjustment sub-interval and its changing trend with the coarse adjustment amplitude gradient, the coarse adjustment amplitude gradient that has a mapping relationship with the combination of the target coarse adjustment sub-interval and the changing trend corresponding to the detected value is the target coarse adjustment amplitude gradient.

[0102] Step S344: Adjust the filament current using the target coarse adjustment range and / or the target coarse adjustment gradient.

[0103] Adjusting the filament current by using the coarse adjustment range and / or target coarse adjustment gradient helps to solve the problem of erroneous accumulation / subtraction caused by the time difference between the acquisition of feedback data and the control of filament current, and avoids the anode current from becoming unstable or other extreme or dangerous situations.

[0104] Step S345: Determine the target detection frequency for coarse tone sub-interval matching.

[0105] A mapping relationship between each coarse adjustment sub-interval and the detection frequency is pre-established. In this mapping relationship, the coarse adjustment stable sub-interval is used as a reference. The greater the offset of other coarse adjustment sub-intervals from this stable sub-interval, the lower the detection frequency matched by that coarse adjustment sub-interval. Therefore, the detection frequency matched by the coarse adjustment stable sub-interval is higher. Taking Tables 1 and 2 as examples, coarse adjustment sub-interval 4 (coarse adjustment stable sub-interval) has the highest matched detection frequency. The matched detection frequencies of coarse adjustment sub-intervals 3 and 5 are lower than those of coarse adjustment sub-interval 4. The matched detection frequencies of coarse adjustment sub-intervals 2 and 6 are lower than those of coarse adjustment sub-intervals 3 and 5. The matched detection frequencies of coarse adjustment sub-intervals 1 and 7 are lower than those of coarse adjustment sub-intervals 2 and 6. Thus, the closer to the coarse adjustment stable sub-interval, the higher the corresponding detection frequency. After determining the target coarse adjustment sub-interval corresponding to the detection value in step S342, the detection frequency that has a mapping relationship with the target coarse adjustment sub-interval is determined by querying the mapping relationship between each coarse adjustment sub-interval and the detection frequency. This detection frequency is the detection frequency that matches the target coarse adjustment sub-interval, i.e., the target detection frequency.

[0106] After determining the target detection frequency for the target coarse-tuning sub-range matching, step S341 is executed again to detect the neutron tube anode current using the latest target detection frequency.

[0107] The following table, in conjunction with Table 3, details the adjustment process during the coarse adjustment phase. In Table 3, m represents the upper limit of the coarse adjustment amplitude (e.g., 700mA), n represents the lower limit of the coarse adjustment amplitude (e.g., 0), k is a constant, PS (first-level gradient) represents a small positive value, PM (first-level gradient) represents a medium positive value, PB (first-level gradient) represents a large positive value, NS (first-level gradient) represents a small negative value, NM (first-level gradient) represents a medium negative value, NB (first-level gradient) represents a large negative value, ZO (first-level gradient) represents no change, and "+ / -" indicates the magnitude of the second-level gradient under the same first-level gradient identifier. That is, the coarse adjustment amplitude gradient consists of the first-level gradient and the second-level gradient, and this coarse adjustment amplitude gradient is fine-tuned based on the first-level gradient through the second-level gradient. More, Mid, and Less represent high, medium, and low detection frequencies, respectively. As shown in Table 3, the coarse adjustment sub-interval [135, 165] marked with interval 4 is the stable coarse adjustment sub-interval. The larger the offset of other coarse adjustment sub-intervals from the main coarse adjustment sub-interval, the larger the coarse adjustment amplitude gradient, the larger the upper limit of the coarse adjustment amplitude, or the smaller the lower limit of the coarse adjustment amplitude, and the lower the corresponding detection frequency. A higher detection frequency indicates more detections within the same time period, and can indirectly reflect the accuracy requirements of a single adjustment of the anode current in different intervals on the feedback data. Therefore, the closer the anode current is to the expected stable interval, the higher the accuracy of the feedback data acquisition, which can reduce the probability of filament current overshoot caused by interference factors.

[0108] Table 3

[0109]

[0110] Step S350: Determine whether the neutron tube anode current meets the coarse adjustment stability condition; if yes, proceed to step S360; if no, proceed to step S340.

[0111] During the coarse adjustment phase, the neutron tube anode current can be continuously checked to see if it meets the coarse adjustment stability condition. That is, it is determined whether the detected value of the neutron tube anode current is stably within the coarse adjustment stability sub-range for a period of time. If so, it means that the neutron tube anode current meets the coarse adjustment stability condition, and the subsequent step S360 is executed to enter the fine adjustment phase; otherwise, step S340 is executed to continue using the adjustment strategy of the coarse adjustment phase.

[0112] In one optional implementation, the coarse adjustment stabilization condition can be: N consecutive detection values ​​are within the coarse adjustment stabilization sub-interval, for example, N can be 200, etc. Taking Table 3 as an example, if the detection values ​​of the neutron tube anode current detected 200 times consecutively are all within [135, 165], then the coarse adjustment stabilization condition is determined to be met.

[0113] Step S360: Enter the fine-tuning stage. In the fine-tuning stage, the filament current is differentially adjusted using a fine-tuning amplitude; wherein, the fine-tuning amplitude is smaller than the coarse-tuning amplitude.

[0114] Once the neutron tube anode current is detected to meet the coarse adjustment stability condition, the fine adjustment stage begins. The fine adjustment stage employs a differential adjustment method: adjusting the filament current using a fine adjustment amplitude. The fine adjustment amplitude is the adjustment range used for each filament current adjustment during the fine adjustment stage, while the coarse adjustment amplitude is the adjustment range used for each filament current adjustment during the coarse adjustment stage; therefore, the fine adjustment amplitude is smaller than the coarse adjustment amplitude.

[0115] In an optional implementation, to further improve the adjustment accuracy of the neutron tube anode current, this implementation can employ, as follows: Figure 6 Steps S361-S368 shown are used to perform differential adjustment of the filament current during the fine-tuning stage:

[0116] Step S361: In the fine-tuning stage, the neutron tube anode current is detected using the target detection frequency, for any detected neutron tube anode current value.

[0117] During the fine-tuning phase, the neutron tube anode current is periodically detected at a corresponding detection frequency. The detected value of the neutron tube anode current is the measured value of the neutron tube anode current. For any detected value, subsequent steps S362-S368 are executed. The frequency used for periodic detection is the target detection frequency, which is dynamically adjusted based on the processing results of subsequent steps.

[0118] Step S362: Calculate the difference between the detected value and the expected stable value of the anode current.

[0119] The absolute value of the difference between the detected value and the expected stable value of the anode current is the difference between the detected value and the expected stable value of the anode current.

[0120] Step S363: Determine the target fine-tuning difference range corresponding to the difference.

[0121] In order to more accurately control the neutron tube anode current and to make the neutron tube anode current quickly stabilize, in this embodiment, the difference space is divided into multiple small intervals. Each interval is a fine adjustment difference interval, which includes the interval start point and the interval end point. After calculating a difference in step S362, the calculated difference is compared with the interval start point and / or interval end point of each fine adjustment difference interval to determine the fine adjustment difference interval corresponding to the difference. The corresponding fine adjustment difference interval is the target fine adjustment difference interval.

[0122] Step S364: Determine the target fine-tuning magnitude gradient and / or target fine-tuning frequency for matching the target fine-tuning difference interval.

[0123] A mapping relationship between each fine-tuning difference interval and the fine-tuning amplitude gradient is pre-established. This fine-tuning amplitude gradient determines the adjustment range and direction of the filament current. The adjustment direction includes positive and negative adjustments, and different fine-tuning difference intervals are matched with different fine-tuning amplitude gradients. Optionally, in the mapping relationship between each fine-tuning difference interval and the fine-tuning amplitude gradient, the larger the fine-tuning difference interval value, the larger the matched fine-tuning amplitude gradient.

[0124] After determining the target fine-tuning difference interval in step S363, the fine-tuning magnitude gradient that has a mapping relationship with the target fine-tuning difference interval is determined by querying the mapping relationship between each fine-tuning difference interval and the fine-tuning magnitude gradient. This fine-tuning magnitude gradient is the fine-tuning magnitude gradient that matches the target fine-tuning difference interval, i.e., the target fine-tuning magnitude gradient.

[0125] A mapping relationship between each fine-tuning differential interval and the fine-tuning frequency can be pre-established. This fine-tuning frequency determines the adjustment speed of the filament current, and different fine-tuning differential intervals are matched with different fine-tuning frequencies. Optionally, in the mapping relationship between each fine-tuning differential interval and the fine-tuning frequency, the larger the fine-tuning differential interval value, the lower the matched fine-tuning frequency.

[0126] After determining the target fine-tuning difference range in step S363, the fine-tuning frequency that has a mapping relationship with the target fine-tuning difference range is determined by querying the mapping relationship between each fine-tuning difference range and the fine-tuning frequency. This fine-tuning frequency is the fine-tuning frequency that matches the target fine-tuning difference range, i.e., the target fine-tuning frequency.

[0127] Step S365: Adjust the filament current using the target fine-tuning amplitude gradient and / or the target fine-tuning frequency.

[0128] The filament current is adjusted once using the target fine-tuning amplitude gradient and / or the target fine-tuning frequency, and step S366 is executed after the adjustment.

[0129] Step S366: Determine whether the adjusted difference is less than the original difference; if not, proceed to step S367; if not, end the fine-tuning process.

[0130] After adjusting the filament current once using the target fine-tuning amplitude gradient and / or target fine-tuning frequency, the detected value of the neutron tube anode current after adjustment is obtained, and the difference between the detected value after adjustment and the expected stable value of the anode current is obtained. This difference is the adjusted difference. The difference between the detected value of the neutron tube anode current before adjustment in step S365 and the expected stable value of the anode current is the unadjusted difference.

[0131] The adjusted difference is compared with the difference before adjustment. If the adjusted difference is greater than or equal to the difference before adjustment, the current fine-tuning process is not over, and step S367 is executed. If the adjusted difference is less than the difference before adjustment, the current fine-tuning process ends, and the next fine-tuning process begins.

[0132] Step S367: Generate a new fine-tuning gradient based on the target fine-tuning gradient, and use the new fine-tuning gradient to adjust the filament current.

[0133] If the adjusted difference is greater than or equal to the original difference, a new fine-tuning gradient is generated based on the target fine-tuning gradient. For example, twice the target fine-tuning gradient can be used as the new fine-tuning gradient, and the filament current can be adjusted using the new fine-tuning gradient.

[0134] After adjustment, step S366 can be executed to determine whether the fine-tuning process is complete. If step S366 determines that the adjusted difference is still greater than or equal to the original difference, then step S367 is executed again. If the adjusted difference is greater than or equal to the original difference, and the number of times step S367 is executed reaches a preset threshold, the fine-tuning process ends.

[0135] Step S368: Determine the target detection frequency for fine-tuning the difference interval matching.

[0136] A mapping relationship between each fine-tuning difference interval and the detection frequency is pre-established, wherein the larger the fine-tuning difference interval, the lower the matching detection frequency. Specifically, when it is determined that step S367 needs to be executed, the target detection frequency matched by the target fine-tuning difference interval can be shortened, and the shortened detection frequency is used as the new target detection frequency.

[0137] Furthermore, in an optional implementation, if a difference is detected to exceed the processing range of the fine-tuning stage or the filament current value after fine-tuning exceeds the coarse-tuning stable range, the coarse-tuning stage is re-entered, thus allowing the coarse-tuning stage and the fine-tuning stage to switch between each other according to actual conditions. For example, if the difference is greater than 20 after a fine-tuning, or if the neutron tube anode current exceeds the coarse-tuning stable range [Xa, X+a] after a fine-tuning, the coarse-tuning stage is re-entered.

[0138] The following section, in conjunction with Table 4, details the adjustment process during the coarse-tuning stage. In Table 4, a larger Diff indicates a larger GAP, resulting in a larger adjustment amplitude during fine-tuning. G1 to G7 represent different fine-tuning amplitude gradients. The fast adjustment flag indicates the type of adjustment frequency used: 0 for slow adjustment, 1 for fast adjustment, F for the adjustment interval corresponding to the fast adjustment frequency, and S for the adjustment interval corresponding to the slow adjustment frequency. A detection frequency of "More" indicates a high detection frequency, and "Less" indicates a low detection frequency.

[0139] Table 4

[0140]

[0141] by Figure 7 The following example will be used to illustrate the specific implementation process of the embodiments of the present invention: Figure 7 As shown, during the preheating stage, the filament current is set to the first filament current value A1 (e.g., 700mA), and the neutron tube anode current continuously increases from 0. When the neutron tube anode current reaches the preset anode current value B1 (e.g., 200uA), the preheating stage transitions to the fallback stage. During the fallback stage, the filament current is set to the second filament current value A2 (e.g., 0), causing the neutron tube anode current to fall back. When the neutron tube anode current falls back to the expected stable anode current value B2 (e.g., 150uA), the stage switches to the coarse adjustment stage. In the coarse adjustment stage, a larger adjustment range is used to adjust the filament current, causing the neutron tube anode current to fluctuate with changes in the filament current. Over time, the neutron tube anode current gradually stabilizes within the coarse adjustment stable sub-range [B2-a, B2+a]. If the neutron tube anode current remains stable within the coarse adjustment stable sub-range [B2-a, B2+a] for a period of time, the fine adjustment stage begins. In the fine-tuning stage, the filament current is adjusted with a smaller adjustment range than in the coarse-tuning stage. This causes the neutron tube anode current to fluctuate with changes in the filament current. Over time, the neutron tube anode current gradually stabilizes within the fine-tuning stable sub-range [B2-b, B2+b], where a > b. For example, b can be 3uA, and a can be 3b~5b, etc. It can be seen that the coarse-tuning fluctuation range of the filament current in the coarse-tuning stage is greater than that in the fine-tuning stage. Correspondingly, the coarse-tuning fluctuation range of the neutron tube anode current in the coarse-tuning stage is greater than that in the fine-tuning stage. Furthermore, the neutron tube anode current continuously converges to the expected stable value B2 from the coarse-tuning stage to the fine-tuning stage, thus ensuring the stability of the neutron tube anode current.

[0142] Therefore, the neutron tube anode current control method based on element logging tool provided in this embodiment of the invention divides the control of neutron tube anode current into a preheating stage, a fallback stage, a coarse adjustment stage, and a fine adjustment stage. In the coarse adjustment stage, a larger adjustment range can shorten the stabilization time of the anode current. In the fine adjustment stage, a smaller adjustment range can ensure the stability accuracy of the anode current. Through the cooperation of the coarse adjustment stage and the fine adjustment stage, the anode current can be dynamically stabilized near the expected stable value of the anode current, thus ensuring the accuracy of the element logging tool.

[0143] Figure 8 This diagram illustrates the structure of a neutron tube anode current control device based on an elemental logging tool, according to an embodiment of the present invention. Figure 8 As shown, the device 800 includes: a preheating module 810, a fallback module 820, a coarse adjustment module 830, and a fine adjustment module 840.

[0144] The preheating module 810 is used to adjust the filament current to the first filament current value during the preheating stage in order to drive the neutron tube anode current to rise.

[0145] The fallback processing module 820 is used to enter the fallback stage after the detected neutron tube anode current rises to a preset anode current value. During the fallback stage, the filament current is adjusted to the second filament current value to drive the neutron tube anode current to fall back.

[0146] The coarse adjustment processing module 830 is used to enter the coarse adjustment stage after the detected neutron tube anode current is less than the expected stable value of the anode current. In the coarse adjustment stage, the coarse adjustment amplitude is used to make differential adjustment to the filament current.

[0147] The fine-tuning processing module 840 is used to enter the fine-tuning stage after the detected neutron tube anode current meets the coarse-tuning stability condition. In the fine-tuning stage, the filament current is differentially adjusted using the fine-tuning amplitude; wherein, the fine-tuning amplitude is smaller than the coarse-tuning amplitude.

[0148] In one alternative implementation, the coarse adjustment processing module 830 is used to: periodically detect the anode current of the neutron tube during the coarse adjustment phase;

[0149] Whenever a value of the neutron tube anode current is detected, the target coarse tuning interval corresponding to that value is determined.

[0150] Determine the target coarse adjustment amplitude range and / or target coarse adjustment amplitude gradient for the target coarse adjustment sub-interval matching, and adjust the filament current using the target coarse adjustment amplitude range and / or target coarse adjustment amplitude gradient.

[0151] In one alternative implementation, the coarse adjustment processing module 830 is used to: whenever a detected value of the neutron tube anode current is detected, determine the trend of change corresponding to that detected value;

[0152] Determine the target coarse adjustment magnitude gradient that matches the target coarse adjustment sub-interval and its corresponding trend of change.

[0153] In one alternative implementation, the coarse adjustment processing module 830 is used to: determine the target detection frequency for matching the target coarse adjustment sub-interval; and use the target detection frequency to detect the neutron tube anode current.

[0154] In one alternative implementation, the fine-tuning processing module 840 is used to: periodically detect the anode current of the neutron tube during the fine-tuning phase;

[0155] Whenever a value of the neutron tube anode current is detected, the difference between the detected value and the expected stable value of the anode current is calculated.

[0156] Determine the target fine-tuning difference range corresponding to the difference;

[0157] Determine the target fine-tuning amplitude gradient and / or target fine-tuning frequency to match the target fine-tuning difference range, and adjust the filament current using the target fine-tuning amplitude gradient and / or target fine-tuning frequency.

[0158] In one optional implementation, the fine-tuning processing module 840 is configured to: after adjusting the filament current using the target fine-tuning amplitude gradient and / or target fine-tuning frequency, determine whether the difference after adjustment is less than the difference before adjustment.

[0159] If not, a new fine-tuning gradient is generated based on the target fine-tuning gradient, and the filament current is adjusted using the new fine-tuning gradient.

[0160] In one optional implementation, the preheating module 810 is used to: after adjusting the filament current to a first filament current value during the preheating stage, if the preheating stage duration reaches a preset duration threshold and the neutron tube anode current does not reach a preset anode current value, then generate an alarm message.

[0161] Therefore, the neutron tube anode current control device based on the element logging tool provided in this embodiment of the invention divides the control of the neutron tube anode current into a preheating stage, a fallback stage, a coarse adjustment stage, and a fine adjustment stage. In the coarse adjustment stage, a larger adjustment range can shorten the stabilization time of the anode current. In the fine adjustment stage, a smaller adjustment range can ensure the stability accuracy of the anode current. Through the cooperation of the coarse adjustment stage and the fine adjustment stage, the anode current can be dynamically stabilized near the expected stable value of the anode current, thus ensuring the accuracy of the element logging tool.

[0162] This invention provides a non-volatile computer storage medium storing at least one executable instruction that can execute the neutron tube anode current control method based on an element logging tool in any of the above method embodiments.

[0163] Figure 9 A schematic diagram of a computing device according to an embodiment of the present invention is shown. The specific embodiments of the present invention do not limit the specific implementation of the computing device.

[0164] like Figure 9 As shown, the computing device may include: a processor 902, a communications interface 904, a memory 906, and a communications bus 908.

[0165] The processor 902, communication interface 904, and memory 906 communicate with each other via communication bus 908. Communication interface 904 is used to communicate with other network elements such as clients or other servers. Processor 902 executes program 910, specifically performing the relevant steps in the above embodiment of the neutron tube anode current control method for element-based logging tools.

[0166] Specifically, program 910 may include program code that includes computer operation instructions.

[0167] Processor 902 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. The computing device includes one or more processors, which may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0168] Memory 906 is used to store program 910. Memory 906 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device. Specifically, program 910 can be used to cause processor 902 to perform the operations described in the above embodiment of the neutron tube anode current control method based on element logging tool.

[0169] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. Various general-purpose systems can also be used in conjunction with the teachings herein. The required structure for constructing such systems is apparent from the above description. Furthermore, the embodiments of the present invention are not directed to any particular programming language. It should be understood that the content of the invention described herein can be implemented using various programming languages, and the above description of specific languages ​​is for the purpose of disclosing the best mode of implementation of the invention.

[0170] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0171] Similarly, it should be understood that, in order to simplify the invention and aid in understanding one or more of the various inventive aspects, features of the embodiments of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into this detailed description, wherein each claim itself is a separate embodiment of the invention.

[0172] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0173] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0174] The various component embodiments of the present invention can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that microprocessors or digital signal processors (DSPs) can be used in practice to implement some or all of the functions of some or all of the components according to the embodiments of the present invention. The present invention can also be implemented as a device or apparatus program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such programs implementing the present invention can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0175] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. A method for controlling the anode current of a neutron tube based on an elemental logging tool, characterized in that, The method includes: During the preheating stage, the filament current is adjusted to the first filament current value to drive the neutron tube anode current to rise. Once the neutron tube anode current is detected to rise to the preset anode current value, it enters the fallback phase. During the fallback phase, the filament current is adjusted to the second filament current value to drive the neutron tube anode current to fall back. Once the neutron tube anode current is detected to be less than the expected stable value of the anode current, the coarse adjustment stage is entered. In the coarse adjustment stage, the filament current is differentially adjusted by the coarse adjustment amplitude. Once the neutron tube anode current is detected to meet the coarse adjustment stabilization condition, the fine adjustment stage begins. In the fine adjustment stage, the filament current is differentially adjusted using a fine adjustment amplitude; wherein, the fine adjustment amplitude is smaller than the coarse adjustment amplitude. The step of differentially adjusting the filament current using a coarse adjustment amplitude during the coarse adjustment stage further includes: During the coarse adjustment phase, the anode current of the neutron tube is periodically monitored. Whenever a value of the neutron tube anode current is detected, the target coarse adjustment interval corresponding to that value is determined. Determine the target coarse adjustment amplitude range and / or target coarse adjustment amplitude gradient for the target coarse adjustment sub-interval matching, and adjust the filament current using the target coarse adjustment amplitude range and / or target coarse adjustment amplitude gradient; If a discrepancy is detected to exceed the processing range of the fine-tuning stage, or if the filament current value after fine-tuning exceeds the stable range of the coarse-tuning stage, the coarse-tuning stage is entered again, thus switching between the coarse-tuning stage and the fine-tuning stage according to the actual situation.

2. The method according to claim 1, characterized in that, The method further includes: Whenever the neutron tube anode current is detected, the corresponding trend of change is determined; Determine the target coarse adjustment magnitude gradient that matches the target coarse adjustment sub-interval and its corresponding trend of change.

3. The method according to claim 1, characterized in that, The method further includes: determining the target detection frequency for target coarse tone sub-interval matching; The periodic detection of the neutron tube anode current during the coarse adjustment phase further includes: detecting the neutron tube anode current using a target detection frequency.

4. The method according to claim 1, characterized in that, The step of differentially adjusting the filament current using a fine-tuning range during the fine-tuning stage further includes: During the fine-tuning phase, the anode current of the neutron tube is periodically monitored. Whenever a value of the neutron tube anode current is detected, the difference between the detected value and the expected stable value of the anode current is calculated. Determine the target fine-tuning difference range corresponding to the difference; Determine the target fine-tuning amplitude gradient and / or target fine-tuning frequency to match the target fine-tuning difference range, and adjust the filament current using the target fine-tuning amplitude gradient and / or target fine-tuning frequency.

5. The method according to claim 4, characterized in that, After adjusting the filament current using the target fine-tuning amplitude gradient and / or target fine-tuning frequency, the method further includes: Determine whether the adjusted difference is less than the original difference; If not, a new fine-tuning gradient is generated based on the target fine-tuning gradient, and the filament current is adjusted using the new fine-tuning gradient.

6. The method according to any one of claims 1-5, characterized in that, After adjusting the filament current to the first filament current value during the preheating stage, the method further includes: if the preheating stage duration reaches a preset duration threshold and the neutron tube anode current does not reach the preset anode current value, then an alarm message is generated.

7. A neutron tube anode current control device based on an elemental logging instrument, characterized in that, The device includes: The preheating module is used to adjust the filament current to the first filament current value during the preheating stage in order to drive the neutron tube anode current to rise. The fallback processing module is used to enter the fallback stage after the detected neutron tube anode current rises to a preset anode current value. During the fallback stage, the filament current is adjusted to the second filament current value to drive the neutron tube anode current to fall back. The coarse adjustment module is used to enter the coarse adjustment stage after the detected neutron tube anode current is less than the expected stable value of the anode current. In the coarse adjustment stage, the filament current is differentially adjusted by the coarse adjustment amplitude. The fine-tuning module is used to enter the fine-tuning stage after the detected neutron tube anode current meets the coarse-tuning stability condition. In the fine-tuning stage, the filament current is differentially adjusted using the fine-tuning amplitude; wherein, the fine-tuning amplitude is smaller than the coarse-tuning amplitude. The coarse adjustment module is used to periodically detect the anode current of the neutron tube during the coarse adjustment phase. Whenever a value of the neutron tube anode current is detected, the target coarse adjustment interval corresponding to that value is determined. Determine the target coarse adjustment amplitude range and / or target coarse adjustment amplitude gradient for the target coarse adjustment sub-interval matching, and adjust the filament current using the target coarse adjustment amplitude range and / or target coarse adjustment amplitude gradient; If a discrepancy is detected to exceed the processing range of the fine-tuning stage, or if the filament current value after fine-tuning exceeds the stable range of the coarse-tuning stage, the coarse-tuning stage is entered again, thus switching between the coarse-tuning stage and the fine-tuning stage according to the actual situation.

8. A computing device, characterized in that, include: The processor, memory, communication interface, and communication bus are provided, wherein the processor, memory, and communication interface communicate with each other via the communication bus. The memory is used to store at least one executable instruction, which causes the processor to perform the operation corresponding to the neutron tube anode current control method based on the element logging tool as described in any one of claims 1-6.

9. A computer storage medium, characterized in that, The storage medium stores at least one executable instruction that causes the processor to perform the operation corresponding to the neutron tube anode current control method based on the element logging tool as described in any one of claims 1-6.

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