Underground natural gamma counting intensity detection device and intensity detection method

Abstract

The invention provides an underground natural gamma counting intensity detection device and method, and belongs to the technical field of oil-gas exploration, and the device comprises a perovskite semiconductor detector which is used for directly absorbing gamma rays from a stratum and generating corresponding electric signals, the perovskite semiconductor detector comprises a sensitive body made of a perovskite semiconductor material, and the sensitive body directly absorbs gamma rays and generates electron-hole pairs; the signal processing circuit is electrically connected with the perovskite semiconductor detector and used for processing the electric signals to obtain measurement data related to gamma ray intensity, and by means of the underground natural gamma ray detection device and method, the efficiency and accuracy of underground natural gamma ray detection can be improved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas exploration technology, specifically to a downhole natural gamma counting intensity detection device and method. Background Technology

[0002] In the field of oil and gas resource exploration and development, natural gamma logging is a fundamental and crucial geophysical logging technology. This technology identifies lithology, delineates formations, estimates clay content, and determines reservoir characteristics by continuously measuring the intensity of natural gamma rays emitted by the formation rocks along the wellbore. Therefore, obtaining high-precision and high-reliability natural gamma logging data is crucial for accurately constructing subsurface geological models and optimizing drilling and production plans. Current methods for downhole natural gamma ray detection employ an indirect detection system combining a scintillation crystal and a photomultiplier tube. In this system, gamma rays are first absorbed by a scintillation crystal (such as a sodium iodide crystal) and converted into visible light photons. These photons are then received by a photomultiplier tube and converted into measurable electrical signals, which are further processed by subsequent circuitry to obtain the count rate.

[0003] In the process of developing this invention, the inventors discovered that existing methods have at least the following problems: First, due to the multi-stage conversion process of "gamma rays → visible light → photoelectrons → multiplying electrons," there are many signal loss and noise introduction stages, resulting in generally low energy resolution of the system (usually worse than 8%), making it difficult to meet the needs of fine energy spectrum analysis of complex formations. Second, the core detector components have poor environmental adaptability. The scintillation crystal and glass-encapsulated photomultiplier tube are extremely sensitive to high temperatures. In downhole environments exceeding 125°C, their performance will degrade sharply or even fail, making them unsuitable for the high-temperature operating conditions of deep wells, ultra-deep wells, or geothermal wells. At the same time, they have poor mechanical stability under harsh downhole conditions of strong vibration and high impact, posing a risk of breakage and delamination, resulting in a high annual damage rate, which seriously affects the continuity of logging operations and the reliability of the equipment. Furthermore, the system has a large size and power consumption. The photomultiplier tube requires a high-voltage power supply and complex temperature drift and gain compensation circuits, which not only limits the development of logging instruments towards miniaturization and modularization but also increases the complexity of the system and maintenance costs.

[0004] In summary, as oil and gas exploration continues to extend into deeper layers, the deep sea, and complex geological environments, existing natural gamma logging technologies face severe challenges in terms of energy resolution, high-temperature stability, mechanical reliability, integration, and cost control. There is an urgent need for a downhole natural gamma ray detection technology that can operate at low cost and high efficiency under complex geological conditions. Summary of the Invention

[0005] In view of this, it is necessary to provide a downhole natural gamma counting intensity detection device and detection intensity method to solve the technical problems of poor environmental adaptability, poor mechanical stability, large signal loss, and high power consumption caused by existing methods in complex geological conditions, resulting in low detection efficiency and high cost.

[0006] To address the aforementioned technical problems, in a first aspect, the present invention provides a downhole natural gamma counting intensity detection device, comprising: A perovskite semiconductor detector is used to directly absorb gamma rays from the strata and generate corresponding electrical signals. The perovskite semiconductor detector includes a sensor made of perovskite semiconductor material, which directly absorbs gamma rays and generates electron-hole pairs. A signal processing circuit, electrically connected to the perovskite semiconductor detector, is used to process the electrical signal to obtain measurement data related to gamma ray intensity.

[0007] In one possible implementation, the signal processing circuit includes: A high-voltage bias module is electrically connected to the perovskite semiconductor detector and is used to provide a stable bias voltage to the perovskite semiconductor detector. The signal amplification module is electrically connected to the output terminal of the perovskite semiconductor detector and is used to amplify the electrical signal with low noise to obtain an electrical pulse signal. The signal counting module is electrically connected to the output terminal of the signal amplification module and is used to count the number of electrical pulse signals per unit time.

[0008] In one possible implementation, the perovskite semiconductor detector further includes a data interface unit for transmitting the measurement data to an external system or for powering the device.

[0009] In one possible implementation, the signal amplification module includes a low-noise preamplifier, which is a charge-sensitive amplifier.

[0010] In one possible implementation, the signal counting module includes a high-speed counter.

[0011] In one possible implementation, the perovskite semiconductor material is selected from one or more of CsPbBr3, MAPbI3, and FAPbBr3, or other semiconductor materials and their derivatives having a perovskite crystal structure.

[0012] In one possible implementation, the perovskite semiconductor detector includes a dual-electrode structure, with the sensor disposed between the dual-electrode structures. The dual-electrode structure includes a top electrode and a bottom electrode, with a spacing of 0.1 mm to 2 mm between the top electrode and the bottom electrode.

[0013] In one possible implementation, the downhole natural gamma-ray counting intensity detection device further includes a thermal insulation structure that at least partially covers the perovskite semiconductor detector, thereby extending the operating temperature range of the perovskite semiconductor detector to above 125°C.

[0014] In one possible implementation, the operating temperature range is 200°C to 260°C.

[0015] On the other hand, the present invention also provides a method for detecting the intensity of natural gamma rays in wells, applied to the aforementioned downhole natural gamma ray counting intensity detection device, comprising: The perovskite semiconductor detector described above absorbs natural gamma rays from the strata and generates a corresponding electrical signal. The electrical signal is processed by the signal processing circuit to obtain measurement data related to the gamma ray intensity.

[0016] The beneficial effects of this invention are as follows: The downhole natural gamma counting intensity detection device provided by this invention achieves direct conversion of gamma rays into charge carriers by using perovskite materials, thereby eliminating the inherent defects such as the luminous efficiency limitation of scintillators and the thermionic emission noise of photomultiplier tubes, which is beneficial to improving energy resolution. At the same time, the device adopts a simple mode of solid-state detector plus integrated circuit, replacing the traditional discrete and bulky scintillators, light guides, photomultiplier tubes, complex high-voltage power supplies and compensation circuits, reducing vulnerable parts (such as glass PMT, optical coupling adhesive) and significantly improving the inherent reliability and shock resistance of the overall structure, which is beneficial to improving the efficiency and accuracy of downhole natural gamma ray detection. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic flowchart of an embodiment of the downhole natural gamma counting intensity detection device provided by the present invention; Figure 2 A schematic flowchart of another embodiment of the downhole natural gamma counting intensity detection device provided by the present invention; Figure 3 This is a schematic diagram of an embodiment of the downhole natural gamma ray detection intensity method provided by the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] In the description of the embodiments of the present invention, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0021] The terms "first," "second," etc., used in the embodiments of this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a technical feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] Before demonstrating the embodiments, the following terms will be explained.

[0024] Perovskite, a type of functional material with an ABX3 crystal structure (A site is usually an organic cation or cesium ion, B site is a lead ion, and X site is a halide ion), has excellent photoelectric properties and a tunable band gap, making it the core material basis for achieving direct radiation detection in this technical solution.

[0025] A perovskite semiconductor detector is a radiation detection device that uses perovskite material as the sensing element. Its working principle is direct detection, that is, gamma rays directly generate electron-hole pairs in the material and form an electrical signal, without the need for traditional scintillators and photomultiplier tubes.

[0026] The Sensitive Volume is the core functional region inside the detector that directly interacts with radiation and generates the initial signal. In this scheme, it specifically refers to the part composed of perovskite material.

[0027] Direct detection is a radiation detection mechanism in which high-energy photons directly generate electron-hole pairs in a semiconductor sensor and are collected as electrical signals. In theory, it has higher energy resolution than indirect detection methods that require a scintillator-photomultiplier tube.

[0028] Electron-hole pairs occur when a semiconductor absorbs radiation energy, causing electrons to be excited from the valence band to the conduction band, while simultaneously leaving a positively charged hole in the valence band. These charge carrier pairs form the basis for electrical signals.

[0029] The band gap is the energy difference between the top of the valence band and the bottom of the conduction band in a semiconductor. The band gap of perovskite materials can be flexibly adjusted by changing the composition, thereby optimizing the detection efficiency of rays of different energies.

[0030] The dual-electrode structure is a common device configuration in perovskite detectors. It typically consists of a top electrode and a bottom electrode, with the perovskite sensor placed between them. When a bias voltage is applied, an electric field is formed to collect the charge.

[0031] Natural Gamma Ray Logging is a geophysical logging method that classifies lithology and identifies clay content by measuring the intensity of gamma rays emitted by the formation rocks themselves.

[0032] Logging While Drilling (LWD) is a logging technology performed simultaneously during the drilling process. It places extremely high demands on the high temperature resistance, shock resistance, and reliability of the instruments, which is the application scenario that this solution aims to adapt to.

[0033] The gamma intensity curve (GR Curve) is a core result obtained from well logging. Its vertical axis represents gamma ray intensity (count rate or API units), and its horizontal axis represents depth, reflecting the vertical variation of formation radioactivity.

[0034] API Units are standardized units of measurement used in natural gamma logging. They were developed by the American Petroleum Institute to unify and compare measurement results from different instruments.

[0035] Gamma rays (γ-rays) are a type of high-energy electromagnetic radiation originating from the decay of atomic nuclei. They have strong penetrating power and are the physical objects detected by natural gamma logging.

[0036] A scintillator, the core component of a traditional radiation detector, is a material (such as NaI crystal) that can convert the energy of high-energy rays (such as gamma rays) into visible light.

[0037] Photomultiplier tubes (PMTs) are key amplification devices in traditional detection systems, used to convert and amplify weak light signals emitted by scintillators into measurable electrical signals. However, they have drawbacks such as large size, fragility, and sensitivity to magnetic fields.

[0038] Energy resolution is a key performance indicator characterizing the detector's ability to distinguish minute differences in the energy of incident particles. The lower the value, the higher the resolution. In this scheme, the direct detection method of perovskite is expected to achieve a high resolution better than 1%.

[0039] The count rate (Counts Per Second, cps) is the number of electrical pulse signals recorded by the detector per unit time, which directly corresponds to the intensity of the incident radiation.

[0040] High-temperature stability refers to the ability of a detector to maintain its key performance without significant degradation when operating for extended periods in high-temperature downhole environments (such as >125°C or even 200°C).

[0041] Shock / Vibration Resistance refers to the detector's ability to resist strong vibrations and mechanical shocks (such as >10g RMS acceleration) generated by downhole drilling tools. All-solid-state perovskite detectors have an advantage in this regard.

[0042] Dark current, the background current generated inside the detector due to thermal excitation and other reasons when there is no radiation exposure, is one of the main noise sources and affects detection sensitivity and energy resolution.

[0043] Bias voltage is a DC operating voltage applied between the two electrodes of the detector to create a strong electric field within the sensitive body, enabling efficient separation and collection of electron-hole pairs generated by radiation.

[0044] A low-noise preamplifier is the first-stage amplifier circuit that follows the detector output. Its core task is to amplify the weak electrical pulses at the nanoampere or microvolt level output by the detector, while minimizing the electronic noise it introduces. Charge-sensitive amplifiers are a commonly used type.

[0045] Pulse shaping filters and shapes the pulse signal output from the preamplifier (e.g., to form a Gaussian wave) to improve the signal-to-noise ratio and standardize its shape, making it easier for subsequent circuits to perform accurate amplitude analysis and counting.

[0046] An analog-to-digital converter (ADC) is a circuit module that converts analog voltage signals into digital signals. In this solution, it is used to digitize the analog signals corresponding to pulse amplitude or count rate for subsequent digital processing, storage, and transmission.

[0047] This invention provides a downhole natural gamma counting intensity detection device and method. The technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0048] Figure 1 The following is a schematic flowchart of an embodiment of the downhole natural gamma counting intensity detection device provided by the present invention. The downhole natural gamma counting intensity detection device includes a perovskite semiconductor detector 101 and a signal processing circuit 102, as detailed below: The perovskite semiconductor detector 101 is used to directly absorb gamma rays from the strata and generate corresponding electrical signals. The perovskite semiconductor detector 101 includes a sensor made of perovskite semiconductor material, which directly absorbs gamma rays and generates electron-hole pairs. The signal processing circuit 102 is electrically connected to the perovskite semiconductor detector 101 and is used to process the electrical signal to obtain measurement data related to the gamma ray intensity.

[0049] The downhole natural gamma-ray counting intensity detection device provided in this embodiment includes two functional units: a perovskite semiconductor detector 101 and a signal processing circuit 102. These two units work together through electrical connection to achieve direct and efficient detection of natural radioactivity in the formation.

[0050] The perovskite semiconductor detector 101 is the sensing core of the entire device, and its function is to complete the first step of energy conversion.

[0051] Specifically, the detector contains a sensor made of a specific perovskite semiconductor material (e.g., a CsPbBr3 polycrystalline thin film or single crystal wafer prepared by solution processing). When natural gamma rays from the formation surrounding the drilling well penetrate the instrument casing and reach the sensor, they interact with it. Unlike traditional scintillators, perovskite materials, as direct bandgap semiconductors, allow electrons to directly absorb the energy of gamma photons, transitioning from the valence band to the conduction band and simultaneously creating holes in the valence band, instantly forming a large number of electron-hole pairs. This physical process eliminates the multi-stage indirect conversion method of first converting gamma rays into visible light and then into electrons through a photocathode, thus avoiding energy information loss and additional noise caused by statistical fluctuations during the conversion stage.

[0052] The signal processing circuit 102 is the data extraction and shaping unit of the device, directly electrically connected to the output of the detector 101. Its core function is to process the initial electrical signal output by the detector. This initial signal is essentially a series of weak, discrete current or voltage pulses formed by electron-hole pairs collected by electrodes under an applied electric field. The task of the signal processing circuit 102 is to capture, amplify, shape, and interpret these pulses, ultimately converting them into standardized measurement data that can intuitively reflect the intensity of gamma rays. This processing ensures that the physical events sensed by the detector can be accurately and reliably recorded and quantified.

[0053] This embodiment utilizes perovskite materials to achieve direct conversion of gamma rays into charge carriers, thereby eliminating inherent defects such as the luminous efficiency limitations of scintillators and the thermionic emission noise of photomultiplier tubes. This provides a physical possibility for the detector to achieve an energy resolution far superior to traditional systems (e.g., from approximately 8%-10% in traditional NaI(Tl)+PMT systems to potentially better than 1%). Secondly, this approach integrates the traditionally discrete and bulky scintillator, light guide, photomultiplier tube, complex high-voltage power supply, and compensation circuitry into a simplified model of a solid-state detector plus integrated circuits. This not only creates conditions for instrument miniaturization but also significantly improves the inherent reliability and shock resistance of the overall structure by reducing vulnerable components (such as glass PMTs and optical coupling adhesives), which is beneficial for improving the efficiency and accuracy of downhole natural gamma ray detection.

[0054] In some embodiments of the present invention, such as Figure 2 As shown, Figure 2 A schematic flowchart of another embodiment of the downhole natural gamma counting intensity detection device provided by the present invention is shown, the signal processing circuit includes: The high-voltage bias module 201 is electrically connected to the perovskite semiconductor detector 101 and is used to provide a stable bias voltage to the perovskite semiconductor detector 101. The signal amplification module 202 is electrically connected to the output terminal of the perovskite semiconductor detector 101 and is used to amplify the electrical signal with low noise to obtain an electrical pulse signal. The signal counting module 203 is electrically connected to the output terminal of the signal amplification module 202 and is used to count the number of electrical pulse signals per unit time.

[0055] In this embodiment, the signal processing circuit includes three functional modules: a high-voltage bias module 201, a signal amplification module 202, and a signal counting module 203. These three functional modules convert the raw, weak electrical signal output by the perovskite semiconductor detector 101 into a complete electronic link for measurement data that can be used for geological interpretation.

[0056] The high-voltage bias module 201 is electrically connected to the perovskite semiconductor detector 101. Its core function is to provide a continuous and highly stable DC bias voltage. This voltage is applied between the detector's two electrodes to establish a strong electric field within the perovskite sensing element. This electric field is a prerequisite for the detector's normal operation; its role is to rapidly separate the electron-hole pairs generated by gamma-ray excitation, causing them to drift towards the electrodes and be effectively collected, forming the initial electrical pulse signal. Specifically, this module needs to have low ripple and high stability output characteristics, because even small fluctuations in the bias voltage directly affect the uniformity of the internal electric field, thus affecting the charge collection efficiency and the stability of energy resolution. Especially considering that the high-temperature environment downhole may cause drift in electronic component parameters, the module design typically includes precision voltage regulation and temperature compensation circuitry to ensure a constant output voltage over a wide temperature range (e.g., above 125°C).

[0057] The signal amplification module 202 is directly connected to the output terminal of the perovskite semiconductor detector 101 to perform primary amplification of the weak electrical pulse signal at the nanoampere or microvolt level output by the detector, and to introduce as little additional noise as possible.

[0058] In some embodiments of the present invention, the signal amplification module 202 includes a low-noise preamplifier, which is a charge-sensitive amplifier. This type of amplifier does not directly amplify the voltage; instead, it integrates the extremely short-duration charge packets collected on the detector output electrodes onto a feedback capacitor, forming a voltage step pulse with an amplitude proportional to the charge amount and a relatively long falling edge. This approach provides an excellent signal-to-noise ratio and reduces the requirements for subsequent circuitry. Subsequently, this voltage pulse undergoes further amplitude amplification and pulse shaping (e.g., shaping into a symmetrical Gaussian pulse) via the main amplifier to eliminate signal tailing, limit noise bandwidth, and create standardized waveform conditions for subsequent accurate discrimination and counting.

[0059] The output terminal of the signal counting module 203 is electrically connected to the output terminal of the signal amplification module 202. Its function is to convert the shaped and uniformly amplitude voltage pulse sequence into digital or analog measurement data characterizing the intensity of gamma rays.

[0060] In some embodiments of the present invention, the signal counting module 203 includes a high-speed counter.

[0061] The counter accumulates valid pulses exceeding a threshold within a unit of time (e.g., 1 second) to obtain the raw count rate (cps). This count rate value can then be linearly converted into an analog voltage signal output via a digital-to-analog converter (DAC); alternatively, it can be directly read into digital form by an analog-to-digital converter (ADC) for processing and buffering by a microprocessor. For the natural gamma-ray counting logging application, the core objective is to measure the total intensity of the radiation rather than the fine energy spectrum. Therefore, this circuit is simplified compared to an energy spectrum analysis system, focusing on linearity and stability at high count rates.

[0062] In this embodiment, a highly stable high-voltage bias ensures the constancy of the internal electric field of the perovskite sensor under complex downhole temperature conditions, thus supporting the realization of high energy resolution and high temperature stability of the detector at the circuit level. Secondly, a low-noise amplification and conditioning link for weak signals is employed to extract high-quality signals. Through charge-sensitive preamplifier combined with pulse shaping technology, signal amplitude information is preserved to the maximum extent while noise is suppressed, improving energy resolution and detection sensitivity to low-intensity radioactive formations. Finally, an efficient and stable signal counting module ensures the accuracy and real-time performance of the measurement data. This embodiment reduces the requirements for processor performance and system power consumption.

[0063] In some embodiments of the present invention, the downhole natural gamma counting intensity detection device further includes a data interface unit for transmitting measurement data to an external system or for powering the device.

[0064] In some embodiments of the present invention, the perovskite semiconductor material is selected from one or more of CsPbBr3, MAPbI3, and FAPbBr3, or is other semiconductor materials and their derivatives having a perovskite crystal structure.

[0065] In this embodiment, the core sensitive material of the perovskite semiconductor detector is specifically defined. Specifically, the perovskite semiconductor material can be one of CsPbBr3, MAPbI3, or FAPbBr3, or a mixture of the above materials, or any other semiconductor material and its derivatives that have perovskite crystal structure characteristics.

[0066] This definition has a clear technical level and inclusivity. First, the listed CsPbBr3 (inorganic perovskite), MAPbI3 (methylamine lead iodide), and FAPbBr3 (formamidinium lead bromine) are typical representative materials with widely studied and recognized photoelectric properties. Their preparation processes are relatively mature, making them highly feasible as examples. For instance, CsPbBr3 is known for its excellent stability and is suitable for environments with high requirements for device lifespan; while MAPbI3 has a high absorption coefficient in the visible light to low-energy gamma-ray band. Second, the term "mixture" covers mixed halide perovskites or mixed cation perovskites formed through solid solution. These methods are key processes for achieving continuous and precise control of the material's bandgap by adjusting the proportion of halogens (Cl, Br, I) or organic cation components, thereby enabling the detector's response characteristics to adapt to the detection requirements of gamma-ray spectra at different geological strata. Finally, other semiconductor materials and their derivatives with perovskite crystal structures, as well as novel perovskite structure materials with similar direct detection capabilities, are also considered, for example, through the partial detection of A-site ions by ions with similar radii (such as rubidium ions Rb). + The B-site ion is replaced by another divalent metal ion (such as tin ion Sn²⁺), or the B-site ion is replaced by another divalent metal ion (such as tin ion Sn²⁺). + The derivatives formed by partial substitution are essentially about maintaining the perovskite lattice framework and its direct bandgap semiconductor properties.

[0067] This embodiment actively optimizes the bandgap of materials such as CsPbBr3 or adjusts its halogen ratio to achieve a better match with the characteristic energy range of gamma rays emitted by common radioactive nuclides in the formation (such as potassium-40, uranium-series, and thorium-series), thereby improving the intrinsic detection efficiency and sensitivity of the detector from a physical perspective. Simultaneously, by introducing specific ion doping or constructing mixed compositions, passivation of defect states in the perovskite lattice is achieved. For example, doping CsPbBr3 with an appropriate amount of strontium (Sr) ions can effectively suppress the formation of deep-level traps, reduce non-radiative recombination and thermally excited dark currents caused by defects, and thus significantly reduce detector noise.

[0068] It is worth mentioning that the material systems listed and covered in this embodiment have a wide range of raw materials (such as cesium salts, lead salts, organic ammonium salts, and halides) and their preparation processes (such as solution methods and thermal evaporation methods) are highly compatible with existing semiconductor processing technologies. This fundamentally supports the advantages of low manufacturing costs and the ability to replace materials with domestically produced alternatives, providing a realistic path to achieve large-scale, self-controlled production and helping to reduce subsequent production and maintenance costs.

[0069] In some embodiments of the present invention, the perovskite semiconductor detector 101 includes a dual-electrode structure, with a sensor disposed between the dual-electrode structure. The dual-electrode structure includes a top electrode and a bottom electrode, and the distance between the top electrode and the bottom electrode is 0.1 mm to 2 mm.

[0070] This embodiment further defines the internal structure of the perovskite semiconductor detector 101. The perovskite semiconductor detector includes a two-electrode structure, with a sensor made of perovskite semiconductor material disposed between the two-electrode structures.

[0071] Specifically, the dual-electrode structure includes a top electrode and a bottom electrode, wherein the spacing between the top electrode and the bottom electrode is limited to the range of 0.1 mm to 2 mm.

[0072] The device structure employed in this embodiment ensures efficient charge collection. The top electrode uses a transparent conductive material (e.g., indium tin oxide (ITO) or fluorine-doped tin oxide (FTO), allowing gamma rays to penetrate the electrode with minimal attenuation and be fully absorbed in the perovskite sensor below. The bottom electrode uses a metal such as gold, aluminum, or silver to form a good ohmic contact for efficient charge collection. Limiting the distance between the two electrodes, i.e., the physical thickness of the sensor, to 0.1 to 2 millimeters is based on engineering considerations that balance gamma ray absorption efficiency with carrier collection efficiency.

[0073] Specifically, if the sensing element is too thin (e.g., less than 0.1 mm), the absorption of high-energy gamma rays will be insufficient, leading to reduced detection efficiency. If the sensing element is too thick (e.g., more than 2 mm), the electron-hole pairs generated by radiation need to drift a longer distance to reach the electrode. During this process, the probability of loss due to recombination with lattice defects and impurities increases significantly, which also weakens the effective signal and reduces energy resolution. Therefore, the thickness range set in this embodiment is designed to provide a path for charge carriers to be effectively collected by the electric field while ensuring a sufficient X-ray absorption cross-section, aiming to optimize overall detection performance.

[0074] In this embodiment, under a given bias voltage, the appropriate electrode spacing facilitates the formation of a sufficiently strong electric field within the sensing element. This allows the electron-hole pairs generated by radiation to be quickly and fully separated and driven towards the corresponding electrodes, reducing recombination losses. This results in a faster response speed for continuously incident gamma rays, enabling the detector to handle higher count rates without easily experiencing pulse accumulation, thereby improving the instrument's dynamic range and measurement accuracy. Simultaneously, this all-solid-state planar structure has no moving parts or fragile optical interfaces, making its mechanical stability superior to traditional PMT systems that include glass vacuum tubes and optical coupling adhesives, and more resistant to downhole vibrations and shocks. Finally, the compact electrode and thin-layer sensing element structure minimizes the overall size and thermal mass of the detector unit. This not only directly contributes to instrument miniaturization but also makes its integration with thermal insulation structures more efficient, as the core heat source requiring insulation is smaller, making it easier to achieve and maintain its high-temperature operating performance.

[0075] In some embodiments of the present invention, the downhole natural gamma counting intensity detection device further includes a thermal insulation structure, which at least partially covers the perovskite semiconductor detector 101 to extend the operating temperature range of the perovskite semiconductor detector to above 125°C.

[0076] In some embodiments of the present invention, the operating temperature range is 200°C to 260°C.

[0077] In an embodiment of this invention applicable to high-temperature downhole environments, the downhole natural gamma-ray counting intensity detection device integrates a specialized thermal insulation structure. This structure physically at least partially covers the perovskite semiconductor detector, and its core function is to create a local thermal buffer environment to block or mitigate the direct heat transfer from the high temperature of the external wellbore to the core sensitive components of the detector. In this way, the actual temperature of the microenvironment where the detector's sensing element is located is significantly lower than the external operating temperature, thereby extending its effective operating temperature range from above 125°C, which the material itself can withstand, to a higher range of 200°C or even 260°C.

[0078] Specifically, the implementation of this thermal insulation structure can refer to mature thermal insulation solutions in the field of downhole instruments. A typical example is the "downhole high-temperature resistant thermos bottle" structure using the principle of vacuum insulation. This involves encapsulating the detector within a double-layered metal shell filled with a high-vacuum interlayer or high-performance thermal insulation materials (such as nano-aerogel), utilizing vacuum or low thermal conductivity media to significantly reduce heat convection and heat conduction. Another feasible example is to add a multi-layered metal shielding structure with heat reflection and heat barrier functions to the outside of the detector, such as a composite thermal insulation sleeve composed of alternating polished high-reflectivity metal layers and low thermal conductivity spacer layers.

[0079] This embodiment achieves reliable operation of the detector under extreme high-temperature well conditions. Downhole temperatures in deep wells, ultra-deep wells, and geothermal resource exploration often exceed 150°C and may even reach over 200°C, at which point traditional photomultiplier tube systems fail. This embodiment, however, utilizes a dual approach of improved material temperature resistance and external active insulation to enable the detector system to operate continuously and stably in such extreme environments. This makes it suitable for a wider range of drilling depths and geological conditions, reducing the risk of operational interruptions due to instrument malfunction caused by high temperatures, and improving the integrity and reliability of exploration data.

[0080] Figure 3 This is a schematic flowchart of an embodiment of the downhole natural gamma ray detection intensity method provided by the present invention. The method is applied to the aforementioned downhole natural gamma ray counting intensity detection device, such as... Figure 3 As shown, the downhole natural gamma ray detection intensity method includes: S301. A perovskite semiconductor detector is used to absorb natural gamma rays from the strata and generate corresponding electrical signals. S302. The electrical signal is processed by the signal processing circuit to obtain measurement data related to the gamma ray intensity.

[0081] like Figure 3 As shown, the downhole natural gamma ray detection intensity method provided in this embodiment is specifically applied to the detection intensity device defined in the foregoing claims, and its execution process is as follows: First, during the instrument deployment and preparation phase, the connection and verification of the device must be completed. Specifically, the downhole instrument unit integrating the perovskite semiconductor detector is connected to the surface recording and power supply system via cable or the drilling system, confirming that the high-voltage bias module, signal amplification module, signal counting module, and data transmission link are all functioning correctly. Subsequently, the downhole instrument is lowered to the predetermined depth in the well. The preset depth is set according to actual application needs and is not limited here.

[0082] As the instrument moves within the wellbore, it performs detection and signal conversion. Natural gamma rays from the surrounding formation pass through the well media and the instrument's casing, and are directly absorbed by the sensor of the perovskite semiconductor detector. Simultaneously, the sensor material, such as CsPbBr3 crystal, has an adjustable bandgap, enabling efficient absorption of gamma-ray photon energy and direct generation of electron-hole pairs. Under an applied bias electric field, these electron-hole pairs rapidly drift to the detector's electrodes and are collected, directly outputting a weak electrical pulse signal related to the incident gamma-ray energy. This method eliminates the two intermediate steps in traditional techniques: first converting gamma rays into visible light, and then using a photomultiplier tube to convert the light into an electrical signal.

[0083] Subsequently, the signal processing and data generation stage begins. The weak electrical pulse signal output by the perovskite semiconductor detector is transmitted to the signal processing circuit. The signal is first amplified by a low-noise preamplifier, such as a charge-sensitive amplifier, to optimize the signal-to-noise ratio. The amplified signal is then shaped by a shaping amplifier to form regular voltage pulses. The shaped pulses are then sent to a signal counting module, where a high-speed counter accumulates the pulses per unit time (e.g., per second) to obtain the raw count rate information. This count rate can be converted into an analog voltage signal by a digital-to-analog converter or directly digitized by an analog-to-digital converter, ultimately forming measurement data directly related to the intensity of gamma rays in the formation.

[0084] Finally, data transmission and interpretation are performed. The generated measurement data is uploaded to the surface system in real time via cable or downhole wireless transmission system. After receiving the data, the surface system processes it synchronously with the corresponding depth information to plot a natural gamma intensity curve that varies with depth. The ordinate of this curve can be in units of counts per second or converted to API units according to industry standards, thus enabling geological interpretation work such as lithology identification, stratigraphic correlation, and clay content estimation.

[0085] This embodiment utilizes perovskite materials to directly convert gamma rays into electrical signals, eliminating the limitations of scintillator luminescence efficiency and the introduction of photomultiplier tube noise, thus laying a fundamental foundation for significantly improving energy resolution. Furthermore, the entire signal chain is based on all-solid-state semiconductor devices, and its operation does not rely on temperature- and magnetic field-sensitive photoelectric emission and multiplication mechanisms. Therefore, this method possesses superior high-temperature stability and resistance to magnetic interference, making it suitable for deep wells and complex magnetic environments. In addition, the downhole natural gamma ray detection intensity method provided in this embodiment relies on a compact device structure that eliminates the need for complex optical coupling and high-voltage compensation adjustments, simplifying on-site operation and significantly improving system reliability.

[0086] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.), and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0087] The above provides a detailed description of the downhole natural gamma counting intensity detection device and detection method provided by the present invention. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A downhole natural gamma counting intensity detection device, characterized in that, include: A perovskite semiconductor detector is used to directly absorb gamma rays from the strata and generate corresponding electrical signals. The perovskite semiconductor detector includes a sensor made of perovskite semiconductor material, which directly absorbs gamma rays and generates electron-hole pairs. A signal processing circuit, electrically connected to the perovskite semiconductor detector, is used to process the electrical signal to obtain measurement data related to gamma ray intensity.

2. The downhole natural gamma counting intensity detection device according to claim 1, characterized in that, The signal processing circuit includes: A high-voltage bias module is electrically connected to the perovskite semiconductor detector and is used to provide a stable bias voltage to the perovskite semiconductor detector. The signal amplification module is electrically connected to the output terminal of the perovskite semiconductor detector and is used to amplify the electrical signal with low noise to obtain an electrical pulse signal. The signal counting module is electrically connected to the output terminal of the signal amplification module and is used to count the number of electrical pulse signals per unit time.

3. The downhole natural gamma counting intensity detection device according to claim 2, characterized in that, The downhole natural gamma counting intensity detection device also includes a data interface unit for transmitting the measurement data to an external system or for powering the device.

4. The downhole natural gamma counting intensity detection device according to claim 2, characterized in that, The signal amplification module includes a low-noise preamplifier, which is a charge-sensitive amplifier.

5. The downhole natural gamma counting intensity detection device according to claim 2, characterized in that, The signal counting module includes a high-speed counter.

6. The downhole natural gamma counting intensity detection device according to claim 1, characterized in that, The perovskite semiconductor material is selected from one or more of CsPbBr3, MAPbI3, and FAPbBr3, or other semiconductor materials and their derivatives with a perovskite crystal structure.

7. The downhole natural gamma counting intensity detection device according to claim 1, characterized in that, The perovskite semiconductor detector includes a dual-electrode structure, with the sensor disposed between the dual-electrode structures. The dual-electrode structure includes a top electrode and a bottom electrode, with a spacing of 0.1 mm to 2 mm between the top electrode and the bottom electrode.

8. The downhole natural gamma counting intensity detection device according to claim 1, characterized in that, It also includes a thermal insulation structure, which at least partially covers the perovskite semiconductor detector, so that the operating temperature range of the perovskite semiconductor detector is extended to above 125°C.

9. The downhole natural gamma counting intensity detection device according to claim 8, characterized in that, The operating temperature range is 200°C to 260°C.

10. A method for detecting the intensity of natural gamma rays in wells, characterized in that, The downhole natural gamma ray counting intensity detection device applied to any one of claims 1 to 9, wherein the downhole natural gamma ray detection intensity method comprises: The perovskite semiconductor detector described above absorbs natural gamma rays from the strata and generates a corresponding electrical signal. The electrical signal is processed by the signal processing circuit to obtain measurement data related to the gamma ray intensity.

Images