Underground magnetic distance measurement transmitting and receiving system and detection method

Abstract

The invention discloses an underground magnetic distance measurement transceiving system and a detection method, and belongs to the technical field of underground resource drilling engineering, the system comprises a transmitting electrode, a first shielding electrode, a second shielding electrode, a loop electrode and a ground case; the ground case is electrically connected with the emission electrode, a first shielding electrode and a second shielding electrode are arranged on the two sides of the emission electrode respectively, and the first shielding electrode and the second shielding electrode are both equipotential with the emission electrode; the emission electrode, the first shielding electrode, the second shielding electrode and the loop electrode are electrically connected. The shielding electrode and the emission electrode are ensured to be equipotential, so that the electric field is radially distributed around the emission electrode, the electric field radially penetrates into the stratum along the surface of the electrode, the current entering the deep position of the stratum through the emission electrode is greatly enhanced, and the collection current on a target sleeve is further enhanced. The depth of a current loop is effectively increased, an induction signal generated by a target is enhanced, and the sensitivity of a detection system is further improved.

Description

Technical Field

[0001] This invention belongs to the field of underground resource drilling and extraction engineering technology, specifically relating to a downhole magnetic ranging transceiver system and detection method. Background Technology

[0002] In the field of oil and gas exploration and development, as shallow oil and gas resources are gradually depleted, the industry is continuously extending into high-risk areas, with the proportion of deep wells, ultra-deep wells, and offshore drilling increasing year by year. Under this trend, exploration faces increasingly complex geological environments, including high temperature and pressure, complex lithology, and poor predictability, such as salt-gypsum layers and fracture-vuggy layers. Faced with these challenges, well blowout accidents can become extremely serious safety hazards.

[0003] According to statistics, approximately 300 well blowouts occur globally every decade, causing casualties and property losses amounting to trillions of yuan. Under extreme conditions such as high temperature, high pressure, and complex lithology, traditional emergency rescue methods are insufficient to handle uncontrolled well blowout emergencies. Utilizing rescue wells at the expected depth downhole to detect, locate, and intercept runaway wells is currently the most reliable method for controlling well blowouts. However, accurately predicting the distance and orientation between rescue wells and runaway wells in unknown, complex, and non-homogeneous downhole media is extremely difficult. Therefore, several passive magnetic ranging (PMR), active magnetic ranging (AMR), and acoustic ranging methods have been proposed and developed. Among these methods, active magnetic ranging offers advantages such as long detection range, high orientation accuracy, and strong anti-interference capabilities, outperforming other methods in detection performance.

[0004] In traditional designs, active magnetic ranging methods typically use bare cables or single electrodes. The current mainly flows back to the receiving electrode along the surface of the drill collar, resulting in a shallow depth and low sensitivity of the detection system. Summary of the Invention

[0005] This invention provides a downhole magnetic ranging transceiver system and detection method that adjusts the electric field distribution, increases the current transmission depth, enhances the induced signal, and improves the detection sensitivity.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A downhole magnetic ranging transceiver system includes a transmitting electrode, a first shielding electrode, a second shielding electrode, a loop electrode, and a ground control box; The ground chassis and the transmitting electrode are electrically connected. A first shielding electrode and a second shielding electrode are respectively provided on both sides of the transmitting electrode. The first shielding electrode and the second shielding electrode are at the same potential as the transmitting electrode. The transmitting electrode, the first shielding electrode, the second shielding electrode and the loop electrode are electrically connected.

[0007] Furthermore, it also includes an adaptive operating frequency system, which is used to simulate the electromagnetic response of various strata environments at different frequencies, and to determine the optimal operating frequency of the transmitting electrode based on the simulation results of the electromagnetic response and the environment.

[0008] Furthermore, the operating frequency adaptive system uses formation conductivity to characterize the formation environment.

[0009] Furthermore, the lengths of the shielding electrode and the emitting electrode are 7 m to 8 m.

[0010] Furthermore, the shielding electrode and the transmitting electrode are armored cables.

[0011] Furthermore, it also includes a measurement unit for measuring the magnetic field and acceleration at the location. Furthermore, it also includes a host computer, which is used to calculate the distance between the measuring unit and the target well casing based on the magnetic field and acceleration measured by the measuring unit at its location.

[0012] A downhole magnetic ranging detection method includes the following steps: Determine the optimal operating frequency based on the formation conductivity; The transmitting power supply provides current to the transmitting electrode at the optimal operating frequency. The first and second shielding electrodes allow the electric field to penetrate into the formation radially along the surface of the transmitting electrode. The target well casing generates a collecting current, which enhances the induced signal from the target well casing. The magnetic field strength and acceleration in the X, Y, and Z directions at the location of the measuring unit are measured. Based on the acceleration in the X, Y, and Z directions and the magnetic field strength in the X, Y, and Z directions, the distance between the measurement location and the target well, as well as the direction of the target well relative to the measurement unit, are obtained through magnetic ranging inversion calculation.

[0013] Furthermore, determining the optimal operating frequency based on the formation conductivity includes: simulating different formation environments, simulating the electromagnetic response at different frequencies under different formation environments, and taking the frequency with the strongest electromagnetic response as the optimal operating frequency of the instrument.

[0014] Furthermore, during the advance of the drill collar, the changes in formation conductivity are continuously monitored, and the operating frequency is adjusted to the optimal operating frequency in real time based on the formation conductivity.

[0015] Compared with the prior art, the present invention has at least the following beneficial technical effects: This invention provides a downhole ranging transceiver system that incorporates a shielding electrode. This shielding electrode alters the electric field distribution around the instrument, thereby changing the direction of current flow in the formation. In-depth research and experimental verification have shown that the shielding electrode significantly improves the formation electric field distribution. By designing the shielding electrode and the transmitting electrode to be at the same potential, the electric field is radially distributed around the transmitting electrode. This electric field penetrates radially into the formation along the surface of the transmitting electrode, greatly enhancing the current that travels deep into the formation via the transmitting electrode, and thus increasing the current collected on the target casing. Compared to traditional methods, the transceiver system proposed in this invention effectively increases the current loop depth, enhances the induced signal generated by the target, and thus improves the sensitivity of the detection system.

[0016] The present invention provides a downhole ranging and transceiver method that utilizes a shielding electrode to make the electric field radially distributed around the transmitting electrode. The electric field penetrates the formation radially along the surface of the transmitting electrode, enhancing the current that penetrates deep into the formation, thereby enhancing the current collected on the target casing, enhancing the induced signal from the target casing, improving detection accuracy, and expanding the detection range.

[0017] Furthermore, this invention designs an optimized operating frequency for different geological environments, fully considering the different characteristics of low-resistivity and high-resistivity strata. By employing an electromagnetic field-based finite element method, more accurate simulations were performed on different geological environments, enabling the measurement unit to operate at the optimal measurement frequency in various geological conditions. This optimized design also improves the measurement stability of the instrument in different geological environments, increasing its reliability in practical applications.

[0018] Overall, through innovative design and systematic optimization, this invention effectively improves the detection accuracy, detection range, and system adaptability of electromagnetic detection technology for rescue wells, providing more reliable and efficient technical support for actual rescue work. Attached Figure Description

[0019] Figure 1 A diagram of an existing downhole detection model without shielded electrodes is shown. Figure 2 A diagram of a downhole detection model with added shielding electrodes according to the present invention is shown; Figure 3 A schematic diagram of the emission electrode structure of the present invention is shown; Figure 4 A schematic diagram of the loop electrode structure of the present invention is shown; Figure 5 A schematic diagram of the measurement unit structure of the present invention is shown; Figure 6 A schematic diagram of the downhole instrument model structure of the present invention is shown; Figure 7 A schematic diagram of the overall structure of the downhole target well casing of the present invention is shown; Figure 8 A schematic diagram of the overall structure of the armored cable for the rescue well of the present invention is shown; Figure 9 The frequency optimization of the current injection method in formations with different resistivity according to the present invention is shown.

[0020] In the attached diagram: 1. Target well casing; 2. Rescue well casing; 3. Host computer; 4. Ground control box; 5. Cable; 6. Transmitting electrode; 7. Measurement unit; 8. Loop electrode; 9. First shielding electrode; 10. Second shielding electrode; 11. Ground. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0022] To enable those skilled in the art to better understand the technical solutions of this invention, 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 embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0023] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or may be interposed with another element. The terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., used herein to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] Firstly, this invention introduces an innovative design for the transmitting electrode: a shielded electrode. For systems based on downhole current injection, the current transmission depth and detection accuracy are crucial to exploration results. Therefore, this invention introduces an innovative shielded electrode design to optimize the arrangement of the transmitting electrode, adjust the electric field distribution, increase the current transmission depth, and enhance the induced signal.

[0026] This invention adds shielding electrodes 9, which are at the same potential as the transmitting electrode 6, to both sides of the transmitting electrode 6. The shielding electrodes 9 can change the electric field distribution around the measuring unit, thereby changing the direction of current flow in the formation. Without the shielding electrodes 9, most of the current flowing from the transmitting electrode 6 flows back to the loop electrode 8 along the drill collar surface, resulting in a low current depth and difficulty in generating a large induced current on the target casing. With the addition of the shielding electrodes 9, because the potentials on both sides of the transmitting electrode 6 are the same, the electric field penetrates deeper into the formation radially along the transmitting electrode surface, increasing the depth of the current loop. This results in a stronger current collection in the target well casing 1 (i.e., the target casing), enhancing the induced signal from the target casing, improving detection accuracy, and expanding the detection range. The overall structure of the target well casing 1 is as follows: Figure 7 As shown.

[0027] Furthermore, this invention optimizes the operating frequency of the measurement unit for different geological environments. Since electromagnetic detection systems in rescue wells typically operate at lower frequencies, traditional methods often employ quasi-static models constrained by the Poisson equation for simulation. In low-resistivity formations, the conduction current is much larger than the displacement current, allowing this method to be used as an approximation. However, in high-resistivity formations, the conduction current density decreases significantly, and the influence of the displacement current cannot be ignored. Since the strength of the displacement current is frequency-dependent, the error introduced by the quasi-static model constrained by the Poisson equation increases considerably.

[0028] This invention utilizes a simulation program based on the electromagnetic field finite element algorithm to accurately simulate different geological environments. By simulating the electromagnetic response at different frequencies, it provides crucial frequency selection criteria for the design of the measurement unit. This precise simulation program offers a more scientific and reliable foundation for optimizing the operating frequency in geological environments, ensuring that the instrument operates at the optimal measurement frequency in various geological conditions. This improves the stability of the instrument's measurements and ensures that it can acquire underground target information more accurately and reliably when facing complex geological environments.

[0029] The following are specific embodiments. It should be noted that these embodiments are preferred examples of the present invention and are intended for those skilled in the art to understand the present invention, but the present invention is not limited to these embodiments.

[0030] Example 1 Reference Figure 1 , Figure 2and Figure 6 This embodiment provides an electromagnetic detection system for a rescue well, mainly composed of a transmitting electrode 6, a first shielding electrode 9, a second shielding electrode 10, a loop electrode 8, a ground housing 4, a cable 5, a host computer 3, a measurement unit 7, and an adaptive operating frequency system. The adaptive operating frequency system can be integrated into the host computer 3 or exist independently. The ground housing 4 and the host computer 3 are located on the ground surface 11, while the transmitting electrode 6, shielding electrode 9, loop electrode 8, cable 5, and measurement unit 7 are all located within the rescue well casing 2. Figure 8 As shown, the rescue well casing 2 is cylindrical.

[0031] The host computer 3 and the ground chassis 4 have a bidirectional communication connection. The ground chassis 4 is connected to cable 5, which in turn connects to the first shielding electrode 9, the transmitting electrode 6, the second shielding electrode 10, the measurement unit 7, and the loop electrode 8. The main function of cable 5 is to electrically connect the first shielding electrode 9, the transmitting electrode 6, the second shielding electrode 10, the measurement unit 7, and the loop electrode 8, and to provide mounting support for these components.

[0032] Each side of the emitting electrode 6 is equipped with a pair of shielding electrodes, such as Figure 3 As shown; circuit electrode 8 Figure 4 As shown, the adaptive operating frequency system is used to adjust the operating frequency of the high-power ground power supply in real time according to the ground conductivity to ensure that the system is in the best working state. This is achieved through precise algorithms and programs.

[0033] Reference Figure 5 The measurement unit 7 includes a triaxial accelerometer and a triaxial fluxgate sensor. The triaxial accelerometer is used to measure acceleration in the X, Y and Z directions. The three-axis fluxgate sensor is used to measure the magnetic field strength in the X, Y, and Z directions. The ground chassis 4 includes an electrically connected transmitting power supply and a data receiving device. The transmitting power supply is electrically connected to the first shielding electrode 9 via cable 5 and is used to supply current to the transmitting electrode 6. The input end of the data receiving device is connected to the output end of the measurement unit 7 and is used to transmit the measurement data to the host computer 3.

[0034] The measurement data includes acceleration in the X, Y, and Z directions and magnetic field strength in the X, Y, and Z directions.

[0035] The host computer 3 is used to receive data from the data receiving device. At the same time, based on the acceleration in the X, Y, and Z directions and the magnetic field strength in the X, Y, and Z directions, it performs magnetic ranging inversion calculation to obtain the distance between the measurement position and the target well, as well as the direction of the target well relative to the measurement unit.

[0036] The operating frequency adaptive system is used to calculate the optimal operating frequency based on the formation conductivity and control the transmitting power supply to operate at the optimal operating frequency.

[0037] The emitting electrode 6 is made of a highly conductive and high-temperature resistant material, such as armored cable. Shielding electrodes 9 with the same potential are mounted on both sides of the emitting electrode 6 to ensure that the electric field penetrates radially into the ground layer from the electrode surface, increasing the depth of the current loop. The distance and dimensions between the shielding electrodes 9 and the emitting electrode 6 are precisely designed to achieve optimal results. The smaller the distance between the shielding electrodes 9 and the emitting electrode 6, the better.

[0038] Preferably, the length of the emitting electrode 6 is 7 m - 8 m.

[0039] In preliminary work, the adaptive operating frequency system was simulated using an electromagnetic field finite element algorithm to determine the optimal operating frequency under different geological environments. The frequency at which the maximum current is collected was chosen based on the geological conductivity of the working site. Simultaneously, the system adjusts the operating frequency in real time based on measurement data during operation to ensure optimal measurement results even when the geological environment changes.

[0040] Simulation results are as follows Figure 9 As shown, (a) represents the simulation results for a formation conductivity of 1 S / m, (b) represents the simulation results for a formation conductivity of 0.1 S / m, (c) represents the simulation results for a formation conductivity of 0.01 S / m, and (d) represents the simulation results for a formation conductivity of 0.001 S / m. Figure 9 It can be seen that the maximum current is achieved at a frequency of 10Hz when the formation conductivity is 1S / m; at a frequency of 100Hz when the formation conductivity is 0.1S / m; at a frequency of 100Hz when the formation conductivity is 0.01S / m; and at a frequency of 1000Hz when the formation conductivity is 0.001S / m. Therefore, the operating frequency is 10Hz when the formation conductivity is 1S / m; 100Hz when the formation conductivity is 0.1S / m; 1000Hz when the formation conductivity is 0.01S / m; and 1000Hz when the formation conductivity is 0.001S / m.

[0041] Example 2 In practical applications, the optimal operating frequency for the rescue well detection system is first determined by an adaptive operating frequency system. Specifically, this embodiment uses a simulation program based on the electromagnetic field finite element algorithm to accurately simulate different geological environments. By simulating the electromagnetic response at different frequencies, the frequency with the strongest electromagnetic response is taken as the operating frequency of the measuring device.

[0042] Once the rescue well detection system is activated, the combined action of the transmitting electrode 6 and the shielding electrode 9 enables the control of the formation electric field, and the measuring unit 7 acquires a stronger electromagnetic induction signal from the target casing in the accident well. During the drill collar's advance, the measuring unit 7 continuously monitors changes in formation conductivity and adjusts the operating frequency in real time based on the formation conductivity to ensure the system is in optimal working condition.

[0043] This embodiment provides a method for detecting rescue wells, based on the electromagnetic detection system for rescue wells provided in Embodiment 1, including the following steps: Step 1: Measure the conductivity of the ground at the working site and input it into the host computer 3. The host computer 3 determines the optimal operating frequency of the transmitting power supply based on the ground conductivity and makes the transmitting power supply operate at the optimal operating frequency. Step 2: The transmitting power supply provides current to the transmitting electrode 6. The first shielding electrode 9 and the second shielding electrode 10 make the electric field penetrate into the formation in the radial direction along the surface of the transmitting electrode 6, increasing the depth of the current loop. The target well casing 1 generates a stronger collecting current, which enhances the induced signal from the target casing. The measuring unit 7 measures the magnetic field strength in the X, Y, and Z directions at its location, as well as its acceleration in the X, Y, and Z directions, and transmits it to the data receiving device. Step 3: The data receiving device transmits the magnetic field strength and acceleration in the X, Y, and Z directions to the host computer 3. Step 4: The host computer 3 receives data from the data receiving device and simultaneously performs magnetic ranging inversion calculations based on the acceleration in the X, Y, and Z directions and the magnetic field strength in the X, Y, and Z directions to obtain the distance between the measurement location and the target well, as well as the direction of the target well relative to the measurement unit. The term "consisting of" in describing a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novel features of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, components, parts, or steps herein also contemplates embodiments essentially composed of these elements, components, parts, or steps. The use of the term "may" herein is intended to indicate that any described attribute included by "may" is optional.

[0044] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0045] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A downhole magnetic ranging transceiver system, characterized in that, It includes a transmitting electrode (6), a first shielding electrode (9), a second shielding electrode (10), a loop electrode (8), and a ground chassis (4). The ground chassis (4) and the transmitting electrode (6) are electrically connected. A first shielding electrode (9) and a second shielding electrode (10) are respectively provided on both sides of the transmitting electrode (6). The first shielding electrode (9) and the second shielding electrode (10) are at the same potential as the transmitting electrode (6). The transmitting electrode (6), the first shielding electrode (9), the second shielding electrode (10) and the loop electrode (8) are electrically connected.

2. The downhole magnetic ranging transceiver system according to claim 1, characterized in that, It also includes an adaptive operating frequency system, which is used to simulate the electromagnetic response of various strata environments at different frequencies, and to determine the optimal operating frequency of the transmitting electrode (6) based on the simulation results of the electromagnetic response and the environment.

3. The downhole magnetic ranging transceiver system according to claim 2, characterized in that, The operating frequency adaptive system uses formation conductivity to characterize the formation environment.

4. The downhole magnetic ranging transceiver system according to claim 1, characterized in that, The lengths of the shielding electrode (9) and the emitting electrode (6) are 7 m to 8 m.

5. The downhole magnetic ranging transceiver system according to claim 1, characterized in that, The shielding electrode (9) and the transmitting electrode (6) are armored cables.

6. The downhole magnetic ranging transceiver system according to claim 1, characterized in that, It also includes a measurement unit (7) for measuring the magnetic field and acceleration at the location.

7. The downhole magnetic ranging transceiver system according to claim 6, characterized in that, It also includes a host computer (3), which is used to calculate the distance between the measuring unit (7) and the target well casing (1) based on the magnetic field and acceleration measured by the measuring unit (7) at the location.

8. A method for downhole magnetic ranging, characterized in that, Includes the following steps: Determine the optimal operating frequency based on the formation conductivity; The transmitting power supply provides current to the transmitting electrode (6), the frequency of which is the optimal operating frequency. The first shielding electrode (9) and the second shielding electrode (10) cause the electric field to penetrate into the formation along the radial direction of the surface of the transmitting electrode (6). The target well casing (1) generates a collecting current, which enhances the induced signal from the target well casing (1). The magnetic field strength and acceleration in the X, Y, and Z directions of the location of the measuring unit (7) are measured. Based on the acceleration in the X, Y, and Z directions and the magnetic field strength in the X, Y, and Z directions, the distance between the measurement location and the target well, as well as the direction of the target well relative to the measurement unit, are obtained through magnetic ranging inversion calculation.

9. The downhole magnetic ranging detection method according to claim 8, characterized in that, The process of determining the optimal operating frequency based on the formation conductivity includes: simulating different formation environments, simulating the electromagnetic response at different frequencies under different formation environments, and taking the frequency with the strongest electromagnetic response as the optimal operating frequency of the instrument.

10. A downhole magnetic ranging detection method according to claim 8, characterized in that, During the advance of the drill collar, the changes in formation conductivity are continuously monitored, and the operating frequency is adjusted to the optimal operating frequency in real time based on the formation conductivity.

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