Well hole full-space time domain electromagnetic detection method and device

Abstract

The invention provides a well hole full-space time domain electromagnetic detection method and device, and the method comprises the steps: transmitting a current pulse to a target stratum through at least one transmitting module, so as to generate a primary field; receiving a plurality of secondary field attenuation signals through a plurality of receiving modules; wherein the secondary field attenuation signal is generated when the target stratum is excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance; and identifying a target stratum according to the plurality of secondary field attenuation signals. According to the borehole total-space time-domain electromagnetic detection method and device provided by the invention, the position of the resistivity abnormal body in the stratum can be accurately identified.

Description

Technical Field

[0001] This application belongs to the field of oil and gas field exploration and development technology, specifically relating to a wellbore full-space time-domain electromagnetic detection method and device. Background Technology

[0002] As oil and gas exploration and development deepens, moving from structural reservoirs to complex and unconventional reservoirs, the difficulty of oil, natural gas, and mineral exploration is gradually increasing, placing higher demands on geophysical exploration technologies. The detection range of conventional logging methods and instruments can no longer fully meet the needs of downhole reservoir-scale logging evaluation. The exploration of complex and unconventional oil and gas reservoirs increasingly requires a thorough understanding of geological structures, lateral reservoir distribution, fracture development, and fault distribution far from the wellbore for precise reservoir-scale evaluation. Existing logging methods and instruments are limited by their detection range, making it difficult to accurately detect and evaluate reservoirs and fluids a few meters or tens of meters away from the well. The resolution scale of seismic exploration in complex oil and gas reservoirs cannot precisely characterize the geological structures near and between wells, favorable reservoir zones, remaining oil distribution, oil-water interfaces, and target layers lost across faults. Furthermore, as the exploration and development of unconventional reservoirs becomes increasingly important, the evaluation of the effects of engineering projects such as reservoir stimulation and acid fracturing in unconventional oil and gas reservoirs is also becoming increasingly prominent. Summary of the Invention

[0003] One objective of this invention is to provide a full-space time-domain electromagnetic detection method for wells, which can identify the location of target formations when using time-domain electromagnetic detection in oil wells.

[0004] Another object of the present invention is to provide a borehole full-space time-domain electromagnetic detection device. A further object of the present invention is to provide an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor, when executing the computer program, implements the steps of the above-described borehole full-space time-domain electromagnetic detection method. A further object of the present invention is to provide a readable medium storing a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of the above-described borehole full-space time-domain electromagnetic detection method.

[0005] To address the technical problems in the background section of this application, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a method for full-space time-domain electromagnetic detection of wells, comprising:

[0007] At least one transmitting module transmits a current pulse to the target formation to generate a primary field;

[0008] Multiple secondary field attenuation signals are received by multiple receiving modules; wherein the secondary field attenuation signals are generated by the target stratum being excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance;

[0009] The target formation is identified based on the multiple secondary field attenuation signals.

[0010] In some embodiments of the present invention, the step of generating the secondary field attenuation signal includes:

[0011] Cut off the current pulse;

[0012] Induced eddy currents are generated in the target stratum through a primary field;

[0013] The secondary field is generated by the induced eddy current to produce the secondary field attenuation signal.

[0014] In some embodiments of the present invention, the transmitting module is a transmitting coil, and there is only one of them; the receiving module is a receiving coil.

[0015] The central axis of the transmitting coil and the central axis of the receiving coil coincide with the spindle of the time-domain electromagnetic detector, and the positions of the multiple receiving coils corresponding to the multiple receiving modules do not coincide in the time-domain electromagnetic detector.

[0016] In some embodiments of the present invention, the transmitting module is a transmitting coil, and there are multiple transmitting coils; the receiving module is a receiving coil; the transmitting coil and the receiving coil are elliptical in shape.

[0017] The coil plane of the transmitting coil forms a first acute angle with the spindle of the time-domain electromagnetic detector, and the coil planes of the other transmitting coils form a second acute angle with the spindle of the time-domain electromagnetic detector. The first acute angle and the second acute angle are complementary, and the coil centers of the multiple transmitting coils coincide.

[0018] The coil plane of the receiving coil forms the first acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other receiving coils forms the second acute angle with the spindle of the time-domain electromagnetic detector, and the coil centers of the multiple receiving coils coincide.

[0019] In some embodiments of the present invention, the transmitting module is a transmitting coil, and there are multiple transmitting coils; the receiving module is a receiving coil; the transmitting coil and the receiving coil are elliptical in shape.

[0020] The coil plane of the transmitting coil forms a third acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other transmitting coils forms a first obtuse angle with the spindle of the time-domain electromagnetic detector. The third acute angle and the first obtuse angle are complementary, and the multiple transmitting coils are adjacent to each other in the position of the time-domain electromagnetic detector.

[0021] The coil plane of the receiving coil forms the third acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other transmitting coils forms the first obtuse angle with the spindle of the time-domain electromagnetic detector, and the plurality of receiving coils are adjacent to each other in the position of the time-domain electromagnetic detector.

[0022] In some embodiments of the present invention, identifying the target formation based on the plurality of secondary field attenuation signals includes:

[0023] The location of the target formation is identified by measuring the intensity and magnitude relationship of the secondary field attenuation signals corresponding to multiple receiving modules as the time-domain electromagnetic probe moves in the wellbore.

[0024] In a second aspect, the present invention provides a wellbore full-space time-domain electromagnetic detection device, the device comprising:

[0025] A primary field generation module is used to transmit current pulses to the target formation through at least one transmitting module to generate a primary field;

[0026] An attenuation signal receiving module is used to receive multiple secondary field attenuation signals through multiple receiving modules; wherein the secondary field attenuation signals are generated by the target stratum being excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance;

[0027] The target formation identification module is used to identify the target formation based on the multiple secondary field attenuation signals.

[0028] In some embodiments of the present invention, a wellbore full-space time-domain electromagnetic detection device further includes:

[0029] Attenuation signal generation module, used to generate the secondary field attenuation signal, the attenuation signal generation module includes:

[0030] A current pulse interruption unit is used to interrupt the current pulse;

[0031] An inductive eddy current generating unit is used to generate inductive eddy currents in the target formation through a primary field.

[0032] The attenuation signal generation unit is used to generate the secondary field through the induced eddy current to generate the secondary field attenuation signal.

[0033] In some embodiments of the present invention, the transmitting module is a transmitting coil, and there is only one of them; the receiving module is a receiving coil.

[0034] The central axis of the transmitting coil and the central axis of the receiving coil coincide with the spindle of the time-domain electromagnetic detector, and the positions of the multiple receiving coils corresponding to the multiple receiving modules do not coincide in the time-domain electromagnetic detector.

[0035] In some embodiments of the present invention, the transmitting module is a transmitting coil, and there are multiple transmitting coils; the receiving module is a receiving coil; the transmitting coil and the receiving coil are elliptical in shape.

[0036] The coil plane of the transmitting coil forms a first acute angle with the spindle of the time-domain electromagnetic detector, and the coil planes of the other transmitting coils form a second acute angle with the spindle of the time-domain electromagnetic detector. The first acute angle and the second acute angle are complementary, and the coil centers of the multiple transmitting coils coincide.

[0037] The coil plane of the receiving coil forms the first acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other receiving coils forms the second acute angle with the spindle of the time-domain electromagnetic detector, and the coil centers of the multiple receiving coils coincide.

[0038] In some embodiments of the present invention, the transmitting module is a transmitting coil, and there are multiple transmitting coils; the receiving module is a receiving coil; the transmitting coil and the receiving coil are elliptical in shape.

[0039] The coil plane of the transmitting coil forms a third acute angle with the spindle of the time-domain electromagnetic detector, and the coil planes of the other transmitting coils form a first obtuse angle with the spindle of the time-domain electromagnetic detector. The first acute angle and the second acute angle are complementary, and the multiple transmitting coils are adjacent to each other in the position of the time-domain electromagnetic detector.

[0040] The coil plane of the receiving coil forms the third acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other receiving coils forms the first obtuse angle with the spindle of the time-domain electromagnetic detector, and the plurality of receiving coils are adjacent to each other in position on the time-domain electromagnetic detector.

[0041] In some embodiments of the present invention, the target stratum identification module includes:

[0042] The target formation identification unit is used to identify the location of the target formation based on the intensity and magnitude relationship of the secondary field attenuation signals corresponding to multiple receiving modules measured by the time-domain electromagnetic probe as it moves in the wellbore.

[0043] Thirdly, the present invention provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of a wellbore full-space time-domain electromagnetic detection method.

[0044] Fourthly, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of a wellbore full-space time-domain electromagnetic detection method.

[0045] Fifthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a wellbore full-space time-domain electromagnetic detection method.

[0046] As described above, embodiments of the present invention provide a wellbore full-space time-domain electromagnetic detection method and apparatus. The corresponding wellbore full-space time-domain electromagnetic detection method includes: firstly, transmitting a current pulse to the target formation through at least one transmitting module to generate a primary field; then, receiving multiple secondary field attenuation signals through multiple receiving modules; wherein, the secondary field attenuation signals are generated by the target formation being excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance; finally, identifying resistivity anomalies in the target formation based on the multiple secondary field attenuation signals.

[0047] The corresponding wellbore full-space time-domain electromagnetic detection device includes: a primary field generation module, used to transmit current pulses to the target formation through at least one transmitting module to generate a primary field; an attenuation signal receiving module, used to receive multiple secondary field attenuation signals through multiple receiving modules; wherein, the secondary field attenuation signals are generated by the target formation being excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance; and a target formation identification module, used to identify resistivity anomalies in the target formation based on the multiple secondary field attenuation signals.

[0048] This invention utilizes one or more transmitting modules and multiple receiving modules positioned at different locations along the instrument axis. Through various combinations, multiple measurement modes are created, and secondary field attenuated electromagnetic signals from multiple receiving modules are acquired under different measurement modes. The differences in the acquired secondary field attenuated electromagnetic signals are then used to accurately identify the location of resistivity anomalies in the formation. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a flowchart illustrating the borehole full-space time-domain electromagnetic detection method in an embodiment of the present invention. Figure 1 ;

[0051] Figure 2 This is a flowchart illustrating the borehole full-space time-domain electromagnetic detection method in an embodiment of the present invention. Figure 2 ;

[0052] Figure 3 This is a flowchart illustrating step 400 of the borehole full-space temporal electromagnetic detection method in an embodiment of the present invention;

[0053] Figure 4 This is a schematic diagram of the structure of the wellbore full-space time-domain electromagnetic remote sounder in an embodiment of the present invention. Figure 1 ;

[0054] Figure 5 This is a schematic diagram of the structure of the wellbore full-space time-domain electromagnetic remote sounder in an embodiment of the present invention. Figure 2 ;

[0055] Figure 6 This is a schematic diagram of the structure of the wellbore full-space time-domain electromagnetic remote sounder in an embodiment of the present invention. Figure 3 ;

[0056] Figure 7 This is a schematic diagram of the structure of the wellbore full-space time-domain electromagnetic remote sounder in an embodiment of the present invention. Figure 4 ;

[0057] Figure 8 This is a flowchart illustrating step 300 of the borehole full-space temporal electromagnetic detection method in an embodiment of the present invention;

[0058] Figure 9 As an embodiment of the present invention Figure 6 The diagram shows the measurement process for identifying resistivity anomalies in the positive X direction when the borehole full-space time-domain electromagnetic remote probe is lowered for measurement.

[0059] Figure 10 As an embodiment of the present invention Figure 6 The diagram shows a measurement process for identifying resistivity anomalies in the positive X direction when the borehole full-space time-domain electromagnetic remote probe is lifted for measurement.

[0060] Figure 11 In a specific embodiment of the present invention Figure 6 The diagram shown illustrates the measurement process for identifying resistivity anomalies in the negative X direction when the borehole full-space time-domain electromagnetic remote probe is lowered for measurement.

[0061] Figure 12 In a specific embodiment of the present invention Figure 6The diagram shows the measurement process for identifying resistivity anomalies in the negative X direction when the borehole full-space time-domain electromagnetic remote probe is lifted for measurement.

[0062] Figure 13 A block of a wellbore full-space time-domain electromagnetic detection device according to an embodiment of the present invention. Figure 1 ;

[0063] Figure 14 A block of a wellbore full-space time-domain electromagnetic detection device according to an embodiment of the present invention. Figure 2 ;

[0064] Figure 15 This is a block diagram of the attenuation signal generation module 40 in an embodiment of the present invention;

[0065] Figure 16 This is a block diagram of the target stratum identification module 30 in an embodiment of the present invention;

[0066] Figure 17 This is a schematic diagram of the structure of an electronic device in an embodiment of the present invention. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0068] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0069] It should be noted that the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. Without conflict, the embodiments and features in the embodiments of this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0070] The acquisition, storage, use, and processing of data in this application comply with relevant laws and regulations.

[0071] Remote wellbore logging is an innovative logging technology developed in recent years. It extends logging from near-wellbore to far-wellbore, providing a new method for remote wellbore logging centered on the wellbore. Based on transient electromagnetic principles, this method utilizes full-space, time-domain electromagnetic remote wellbore logging technology. It can overcome the limitations of existing logging methods and technologies in terms of spatial evaluation scale, providing a detailed description of the structural morphology, reservoir distribution, oil and gas enrichment zones, and fluid distribution of reservoirs far from the wellbore. It can dynamically monitor the sweep front and direction of water-drive, steam-drive, and polymer-drive operations during oilfield development, improving the drilling rate of horizontal wells in rolling exploration and development, and ultimately increasing the recovery rate. In terms of detection depth and resolution, it fills the gaps in the geological evaluation scales of conventional logging and seismic exploration.

[0072] Traditional frequency-domain electromagnetic logging achieves long-distance detection by lowering the frequency and increasing the transmit / receive offset, resulting in increased detector length and weight, and limited detection range. In contrast, time-domain electromagnetic long-distance detection technology achieves this by measuring the decay process of the electromagnetic field excited by the current pulse turn-off process. It can achieve well-side long-distance detection with a shorter instrument length, which requires longer instruments in the frequency domain.

[0073] Unlike surface-based half-space time-domain electromagnetic remote sensing, borehole time-domain electromagnetic remote sensing is a full-space detection method. That is, when a borehole full-space time-domain electromagnetic remote sensing instrument is working downhole, the formation information it acquires comes from the geological bodies in a 360° azimuth around the instrument's location, making it difficult to identify the orientation of the surrounding formations relative to the instrument's location.

[0074] To address the aforementioned technical challenges, embodiments of the present invention provide a specific implementation of a wellbore full-space time-domain electromagnetic detection method, see [link to details]. Figure 1 The full-space time-domain electromagnetic detection method for wells specifically includes the following:

[0075] Step 100: Transmit a current pulse to the target formation through at least one transmitting module to generate a primary field;

[0076] Step 200: Receive multiple secondary field attenuation signals through multiple receiving modules; wherein the secondary field attenuation signals are generated by the target stratum being excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance;

[0077] Step 300: Identify the target formation based on the multiple secondary field attenuation signals.

[0078] As described above, this invention provides a wellbore full-space time-domain electromagnetic detection method. By setting one or more transmitting modules and multiple receiving modules at different positions along the instrument axis, various measurement modes are formed through different combinations. Secondary field attenuated electromagnetic signals from multiple receiving modules are collected under different measurement modes. Because the distance and orientation of the target formation differ between different transmitting and receiving modules under different measurement modes, the secondary field attenuated electromagnetic signals collected by different receiving modules differ in different measurement modes. The location of the target formation is identified by the differences in the collected secondary field attenuated electromagnetic signals.

[0079] For step 100, a high-power current pulse is transmitted to the ground through at least one transmitting module to generate a primary field. This primary field refers to the electromagnetic field generated when the current changes rapidly over a short period of time. The current pulse can generate strong electric and magnetic fields that change rapidly over time and can propagate quickly in the surrounding space.

[0080] The fundamental principle behind the generation of this primary field is that the movement of electric charge causes changes in the electromagnetic field. When current flows through a conductor, it generates a magnetic field around the conductor; when the current changes rapidly, the generated magnetic field also changes accordingly. According to Faraday's law, a changing magnetic field generates an electric field. This instantaneous electromagnetic field generated by a current pulse has unique propagation characteristics and effects. The primary field has the following characteristics: the current pulse is characterized by a rapid change in current magnitude within a very short time, which leads to rapid changes in the generated electric and magnetic fields. The primary field generated by the current pulse propagates in the form of electromagnetic waves. These electromagnetic waves propagate according to the predictions of Maxwell's equations, at a speed approximately the speed of light. According to Faraday's law of electromagnetic induction, a changing magnetic field generates an electric field in the surrounding space. Therefore, a current pulse not only directly generates a magnetic field but also indirectly generates a time-varying electric field. While Ampere's law describes the generation of a magnetic field by a current, Maxwell's added corrections indicate that a changing electric field can also generate a magnetic field. Therefore, in the primary field generated by a current pulse, the changing electric field can also generate a new magnetic field.

[0081] For step 200, based on step 100, the primary field penetrates the strata, generating a secondary field within the strata. These secondary fields contain information about the subsurface structure; by measuring the intensity and distribution of these secondary fields, the subsurface material composition, structural layout, and other characteristics can be inferred. The distance between the transmitting module and the receiving module is a preset distance (specifically, this preset distance can also be 0). This preset distance can be determined based on the instrument's structural characteristics.

[0082] Step 300 can be implemented as follows: When the primary field pulse magnetic field is interrupted, the induced current in the conductor in the formation does not disappear immediately, but rather undergoes a gradual process of diffusion, decay, and disappearance according to an exponential law. The decay process of the secondary field over time is collected by the receiving module, and multiple secondary field decay signals are collected by multiple receiving modules under different measurement modes. Different transmitting modules and different receiving modules differ due to the different distances and orientations of the target formation, resulting in differences in the secondary field decay electromagnetic signals collected by different receiving modules. Therefore, the location of the target formation in the formation can be identified by the different secondary field decay signals.

[0083] Specifically, when the target stratum contains resistivity anomalies (resistivity anomalies refer to areas in underground strata whose resistivity differs significantly from the surrounding rocks. Such anomalies may be caused by different geological conditions, such as the presence of minerals, changes in porosity, water content, or different rock types), the intensity and degree of the secondary field attenuation signal generated by these anomalies are significantly different from those when the target stratum does not contain resistivity anomalies. Specifically, when the target stratum contains resistivity anomalies, the intensity of the secondary field attenuation signal generated by the stratum differs (the intensity of the secondary field attenuation signal increases when the target stratum contains a low resistivity anomaly; the intensity of the secondary field attenuation signal decreases when the target stratum contains a high resistivity anomaly). Therefore, this characteristic can be used to identify resistivity anomalies in the target stratum.

[0084] In some embodiments of the present invention, see Figure 2 A wellbore full-space time-domain electromagnetic detection method, further comprising:

[0085] Step 400: Generate the secondary field attenuation signal, then refer to... Figure 3 Step 400 includes:

[0086] Step 401: Cut off the current pulse;

[0087] Step 402: Induced eddy currents are generated in the target stratum using a primary field;

[0088] Induced eddy currents are closed loops of current generated within a conductor when it is placed in a changing magnetic field. The generation of these currents follows Faraday's law of electromagnetic induction, which states that a changing magnetic field at any given time will induce an electromotive force (EMF) in its surrounding region, thereby generating a current in the conductor. The generation of induced eddy currents depends on the following factors: there must be a conductor (usually a metal), because eddy currents are a form of electric current and require free electrons to flow within the material. The magnetic field must be changing, because a static magnetic field will not induce a current in a conductor. The relative motion between the conductor and the magnetic field promotes the generation of eddy currents. This motion can be the conductor moving into or out of a region of magnetic field, or a change in the magnetic field itself around the conductor.

[0089] Step 403: Generate the secondary field through the induced eddy current to generate the secondary field attenuation signal.

[0090] In some embodiments of the present invention, see Figure 4 as well as Figure 5 The transmitting module is a transmitting coil T1 104, and there is only one transmitting coil. The receiving module is a receiving coil, and there are two receiving coils, namely R1 103 and R2 102.

[0091] The central axis of the transmitting coil T1 104 and the central axes of the receiving coils R1 103 and R2 102 coincide with the spindle 101 of the time-domain electromagnetic detector, and the positions of the multiple receiving coils corresponding to the multiple receiving modules do not coincide in the time-domain electromagnetic detector.

[0092] In some embodiments of the present invention, see Figure 6 The transmitting module consists of multiple transmitting coils, namely Tx1 201 and Tx2 202, and the receiving module consists of receiving coils Rx1 203 and Rx2 204; both the transmitting coil and the receiving coil are elliptical in shape.

[0093] The coil plane of the transmitting coil Tx1 201 (or Tx2 202) forms a first acute angle (range 10° to 80°, preferably 45°) with the spindle 101 of the time-domain electromagnetic detector, and the coil plane of the other transmitting coil Tx2 202 (corresponding to the above, it can also be Tx1 201 here, the same below) forms a second acute angle (range 10° to 80°, preferably 45°) with the spindle 101 of the time-domain electromagnetic detector, and the first acute angle and the second acute angle are complementary, and the coil centers of the multiple transmitting coils Tx1 201 and Tx2 202 coincide;

[0094] The coil plane of the receiving coil Rx1 203 forms the first acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other receiving coil Rx2 204 forms the second acute angle with the spindle of the time-domain electromagnetic detector, and the coil centers of the multiple receiving coils coincide.

[0095] In some embodiments of the present invention, see Figure 7 The transmitting module consists of multiple transmitting coils, namely Tx1 201 and Tx2 202, and the receiving module consists of receiving coils Rx1 203 and Rx2 204; the transmitting coils Tx1 201 and Tx2 202 and the receiving coils Rx1 203 and Rx2 204 are all elliptical in shape.

[0096] The coil plane of the transmitting coil Tx1 201 forms a third acute angle with the spindle 101 of the time-domain electromagnetic detector (ranging from 10° to 80°, preferably 45°), and the coil plane of the other transmitting coil Tx2 202 forms a first obtuse angle with the spindle of the time-domain electromagnetic detector. The third acute angle and the first obtuse angle are complementary, and the multiple transmitting coils Tx1 201 and Tx2 202 are adjacent in position to the time-domain electromagnetic detector.

[0097] See also Figure 7 The coil plane of the receiving coil Rx1 203 forms a third acute angle (ranging from 10° to 80°, preferably 45°) with the spindle of the time-domain electromagnetic detector, and the coil plane of the other receiving coil Rx2 204 forms a first obtuse angle with the spindle 101 of the time-domain electromagnetic detector, and the plurality of receiving coils Rx1 203 and Rx2 204 are adjacent to each other in position on the time-domain electromagnetic detector.

[0098] In some embodiments of the present invention, see Figure 8 Step 300 includes:

[0099] Step 301: Identify the location of the target formation based on the intensity and magnitude relationship of the secondary field attenuation signals corresponding to multiple receiving modules measured by the time-domain electromagnetic probe as it moves in the wellbore.

[0100] See Figure 9The figure shows the XZ plane, with the Z-axis representing the instrument axis and well axis. Taking the remote probe's downsinking measurement as an example, at time t1, when the anomaly is located below the device and in the positive X-axis direction, the line connecting the center point M of the resistivity anomaly in the formation (this embodiment assumes the target formation contains a low resistivity anomaly; when the target formation contains a low resistivity anomaly, the secondary field attenuation signal strength increases; when the target formation contains a high resistivity anomaly, the secondary field attenuation signal strength decreases) and the center point O of the detector is approximately aligned with the normal directions of the transmitting coil module Tx2 201 and the receiving coil module Rx2 203, and approximately perpendicular to the normal directions of the transmitting coil module Tx1 202 and the receiving coil module Rx1 204. At this time, the anomaly signal measured in the receiving coil module Rx2 203 is stronger than the anomaly signal measured in the receiving coil module Rx1 204.

[0101] As the remote sensing instrument is lowered, at time t2, the relative position between the anomaly and the instrument gradually changes. The anomaly is now above the instrument. At this point, the line connecting the center point M of the anomaly and the center point O of the detector is approximately aligned with the normal directions of the transmitting coil module Tx2 202 and the receiving coil module Rx2 204, and approximately perpendicular to the normal directions of the transmitting coil module Tx1 201 and the receiving coil module Rx1 203. At this time, the anomaly signal measured in the receiving coil module Rx2 204 is stronger than the anomaly signal measured in the receiving coil module Rx1 203. This allows for the identification of the resistivity anomaly's location within the formation.

[0102] Next, see Figure 10 If the remote detector is raised for measurement, at time t1, when the anomaly is above the remote detector and in the positive X-axis direction, the direction of the line connecting the center point M of the anomaly and the center point O of the detector is approximately consistent with the normal directions of the transmitting coil module Tx2 202 and the receiving coil module Rx2 204, and approximately perpendicular to the normal directions of the transmitting coil module Tx1 201 and the receiving coil module Rx1 203. At this time, the anomaly signal measured in the receiving coil module Rx2 204 is stronger than the anomaly signal measured in the receiving coil module Rx1 203.

[0103] As the telescope is raised, at time t2, the relative position between the anomaly and the telescope changes, with the anomaly positioned below the telescope. At this point, the line connecting the center point M of the anomaly and the center point O of the detector is approximately aligned with the normal directions of the transmitting coil module Tx2 201 and the receiving coil module Rx2 203, and approximately perpendicular to the normal directions of the transmitting coil module Tx1 202 and the receiving coil module Rx1 204. At this time, the anomaly signal measured in the receiving coil module Rx2 203 is stronger than the anomaly signal measured in the receiving coil module Rx1 204. This is used to identify the anomaly's location within the strata.

[0104] As described above, this invention provides a wellbore full-space time-domain electromagnetic detection method. One or more transmitting modules and multiple receiving modules are set at different positions on the instrument axis of the wellbore full-space time-domain electromagnetic logging tool. By different combinations of transmitting and receiving modules, multiple measurement modes are formed. Secondary field attenuated electromagnetic signals from multiple receiving modules are collected under different measurement modes. Different transmitting and receiving modules under different measurement modes differ due to differences in the distance and orientation of the target formation, resulting in differences in the secondary field attenuated electromagnetic signals collected in different receiving modules. The location of the target formation is identified by the different secondary field attenuated electromagnetic signals collected.

[0105] Specifically, the wellbore full-space time-domain electromagnetic remote sounding instrument provided by this invention places a transmitting device and a receiving device simultaneously in an oil wellbore. The transmitting device emits a pulse into the formation, generating a primary field in the surrounding space. Under the excitation of the primary pulse, eddy currents are induced in good conductors due to the principle of electromagnetic induction, and these induced eddy currents generate a secondary field in the surrounding space. When the primary field pulse is interrupted, the induced current in the conductor does not disappear immediately, but gradually diffuses, decays, and disappears according to an exponential law. The receiving device collects the process of the secondary field decaying over time, and multiple receiving modules acquire multiple secondary field decay signals under different measurement modes. Due to differences in the distance and orientation of the target formation between different transmitting and receiving modules under different measurement modes, the secondary field decay electromagnetic signals acquired by different receiving modules under different measurement modes vary. The location of the target formation is identified by these different secondary field decay signals.

[0106] The borehole full-space time-domain electromagnetic long-range sounder consists of a circuit section and a detector section. The circuit section comprises a transmitting circuit module, a control circuit module, and a data processing and transmission module. The detector section is equipped with at least one transmitting module and at least two receiving modules. The receiving modules measure and acquire secondary field attenuation signals to identify the location of the target formation. The transmitting and acquisition modules are mounted in series on a mandrel, which provides skeletal support for the detector.

[0107] The transmitting module of the time-domain electromagnetic long-range detector is connected to the transmitting circuit via wires. The transmitting circuit generates a pulse signal of a certain intensity, which is transmitted to the formation via the transmitting module. When the magnetic field of the primary field pulse is interrupted, the receiving module collects the process of the secondary electromagnetic field generated by induced eddy currents in the formation decaying over time. The receiving module is connected to the receiving circuit via wires. The acquired signal of the secondary electromagnetic field decaying over time is further converted to obtain the formation's electrical parameters. Multiple receiving modules acquire multiple secondary field decay signals under different measurement modes. Because different receiving modules differ due to variations in the distance and orientation of the target formation, the secondary field decay signals acquired by different receiving modules will differ, thus enabling the identification of the target formation's location.

[0108] In one specific embodiment, the present invention also provides a specific implementation of a wellbore full-space time-domain electromagnetic detection method, which specifically includes the following:

[0109] First, this invention provides a borehole full-space time-domain electromagnetic long-range sounding instrument, which consists of one or more spindles, one or more transmitting modules, and multiple receiving modules. The transmitting modules are connected to a transmitting circuit via wires. The transmitting circuit generates a high-power current pulse, which travels through the wires to the transmitting module. The transmitting module emits a primary pulse towards the formation, generating a primary field in the surrounding space. Excited by the primary pulse, eddy currents are induced in good conductors due to the principle of electromagnetic induction, generating a secondary field in the surrounding space. When the primary field pulse magnetic field is interrupted, the induced current in the conductor does not immediately disappear, but rather undergoes a gradual process of diffusion, decay, and disappearance according to an exponential law. The receiving device collects the decay process of the secondary field over time. Multiple receiving modules acquire multiple secondary field decay signals under different measurement modes. Differences exist between different transmitting and receiving modules due to variations in the distance and orientation of the target formation, resulting in differences in the secondary field decay electromagnetic signals acquired by different receiving modules. The location of the target formation is identified by these different secondary field decay signals.

[0110] See Figure 4 This provides a preferred configuration for a borehole full-space time-domain electromagnetic remote sounder, which consists of at least one transmitting coil module T1 104, at least two receiving coil modules R1103 and R2102, and a spindle 101. Figure 4The transmitting coil module T1 104 shown is a Z-direction coil, and at least two receiving coil modules R1 103 and R2 102 are Z-direction coils. The central axes of T1 104, R1 103, and R2 102 coincide with the central axis of the spindle. The transmitting coil module T1 104 is fixed on the spindle 101, and the spindle and the transmitting coil module are insulated from each other. The transmitting coil module T1 104 is connected to the transmitting circuit through a wire. The transmitting circuit generates a high-power current pulse, which is transmitted to the ground plane through the transmitting coil module via the wire. The receiving coil modules R1 103 and R2 102 shown are fixed on the spindle 101, and the spindle 101 is insulated from the receiving coil modules R1 103 and R2 102. The receiving coil modules R1 103 and R2 102 are insulated from each other and are connected to the acquisition circuit through a wire. Figure 4 As shown, 107 represents the wellbore, and Rt1 105 represents the formation where the electromagnetic remote sounder is located. When the anomaly Rt2 106 is located below the electromagnetic remote sounder, the receiving coil module R1 103 is closer to the anomaly Rt2 106 than the receiving coil module R2 102. Therefore, the anomaly signal measured in receiving coil module R1 103 is stronger than the anomaly signal measured in receiving coil module R2 102. The acquisition circuit collects and records the decay process of the secondary field induced in receiving coil modules R1 103 and R2 102 over time, and identifies the location of the target formation by the different secondary field decay signals.

[0111] Next, see Figure 5 Here, we will still take the preferred configuration of the aforementioned wellbore full-space time-domain electromagnetic remote sounder as an example to explain the structure and working principle of the wellbore full-space time-domain electromagnetic remote sounder. Figure 5 In the diagram, 107 represents the wellbore, and Rt1 105 represents the formation where the electromagnetic remote sounder (EMS) is located. When the anomaly Rt2 106 is above the EMS, the anomaly signal measured in receiving coil module R1 103 is weaker than that measured in receiving coil module R2 102 because receiving coil module R1 103 is farther from Rt2 106 than receiving coil module R2 102. The acquisition circuit collects and records the decay process of the secondary field induced in receiving coil modules R1 103 and R2 102 over time, and identifies the location of the target formation by using the different secondary field decay signals.

[0112] See Figure 6 as well as Figure 7 Here are two other preferred configuration options for the wellbore full-space time-domain electromagnetic remote sounder:

[0113] The borehole full-space time-domain electromagnetic remote sounder consists of at least two tilted transmitting coil modules Tx1 and Tx2, at least two tilted receiving coil modules Rx1 and Rx2, and a spindle 101. Figure 6 The diagram shows at least two transmitting coil modules Tx1 201 and Tx2 202, and at least two receiving coil modules Rx1 203 and Rx2 204. Tx1 201 and Rx1 203 are elliptical x-direction coils, with their coil planes forming an angle of 45° with the central axis of the mandrel 101 (this angle can be within a range, e.g., 10° to 80°). Tx2 202 and Rx2 204 are elliptical x-direction coils, with their coil planes forming an angle of 135° with the central axis of the mandrel 101. Transmitting coil modules Tx1 201 and Tx2 202 are fixed at the same position on the mandrel 101, as shown... Figure 6 As shown, or fixed at a position adjacent to the mandrel.

[0114] like Figure 7 As shown. The mandrel is insulated from the transmitting coil module. Transmitting coil modules Tx1 201 and Tx2 202 are connected to the transmitting circuit via wires. The transmitting circuit generates a high-power current pulse, which travels through the wires to the transmitting coil module and transmits a single pulse to the ground. Receiving coil modules Rx1 203 and Rx2 204 are fixed at the same position on the mandrel 101, as shown. Figure 6 As shown, or fixed at a position adjacent to the mandrel, such as Figure 7 As shown. The spindle 101 is insulated from the receiving coil modules Rx1 203 and Rx2 204. The distance between the transmitting coil module Tx1 201 and the receiving coil module Rx1 203 is equal to the distance between the transmitting coil module Tx2 202 and the receiving coil module Rx2 204. The receiving coil modules Rx1 203 and Rx2 204 are connected to the acquisition circuit via wires. The instrument operates in a time-division multiplexing mode, with transmitting coil modules Tx1 201 and Tx2 202 transmitting in a time-division multiplexing manner. When transmitting coil module Tx1 201 transmits, Rx1 203 and Rx2 204 receive; when transmitting coil module Tx2 202 transmits, Rx1 203 and Rx2 204 receive.

[0115] The acquisition circuit acquires and records the decay process of the secondary field induced in the receiving coil modules Rx1 203 and Rx2 204 over time, and identifies the X-direction orientation of the target stratum through different secondary field decay signals.

[0116] Based on the structure and working principle of the wellbore full-space time-domain electromagnetic remote sounder described above, see [link to documentation]. Figure 9 , Figure 10 , Figure 11 as well as Figure 12 The specific implementation of the wellbore full-space time-domain electromagnetic detection method provided by the present invention includes the following steps:

[0117] Figure 9 as well as Figure 10 The specific implementation steps of the wellbore full-space time-domain electromagnetic detection method have been described previously and will not be repeated here.

[0118] See Figure 11 (Plane in the XZ direction), when the anomaly is located in the negative X direction of the detector, the Z-axis is the direction of the instrument axis and the well axis. Taking the remote detector measurement as an example of the drop measurement, at time t1, when the anomaly is located below the remote detector and in the negative X direction, the direction of the line connecting the center point M of the anomaly and the center point O of the detector is approximately consistent with the normal direction of the transmitting coil module Tx2 202 and the receiving coil module Rx2 204, and approximately perpendicular to the normal direction of the transmitting coil module Tx1 201 and the receiving coil module Rx1 203. At this time, the anomaly signal measured in the receiving coil module Rx2 204 is stronger than the anomaly signal measured in the receiving coil module Rx1 203.

[0119] As the instrument is lowered, at time t2, the relative position between the anomaly and the remote detector changes. The anomaly is now above the remote detector. At this point, the line connecting the center point M of the anomaly and the center point O of the detector is approximately aligned with the normal directions of the transmitting coil module Tx2201 and the receiving coil module Rx2203, but approximately perpendicular to the normal directions of the transmitting coil module Tx1202 and the receiving coil module Rx1204. At this time, the anomaly signal measured in the receiving coil module Rx2203 is stronger than the formation signal measured in the receiving coil module Rx1204.

[0120] In this situation, if the remote detector is raised to measure, such as Figure 12 As shown, at time t1, when the anomaly is located above the remote detector and in the negative X-axis direction, the line connecting the center point M of the anomaly and the center point O of the detector is approximately aligned with the normal directions of the transmitting coil module Tx2 201 and the receiving coil module Rx2 203, and approximately perpendicular to the normal directions of the transmitting coil module Tx1 202 and the receiving coil module Rx1 204. At this time, the anomaly signal measured in the receiving coil module Rx2 203 is stronger than the anomaly signal measured in the receiving coil module Rx1 204.

[0121] As the telescope is raised, at time t2, the relative position between the anomaly and the telescope changes, with the anomaly positioned below the telescope. At this point, the line connecting the center point M of the anomaly and the center point O of the detector is approximately aligned with the normal directions of the transmitting coil module Tx2 202 and the receiving coil module Rx2 204, and approximately perpendicular to the normal directions of the transmitting coil module Tx1 201 and the receiving coil module Rx1 203. At this time, the anomaly signal measured in the receiving coil module Rx2 204 is stronger than the anomaly signal measured in the receiving coil module Rx1 203. Therefore, the target stratum identified is located in the negative X direction of the detector. The method and principle for identifying the anomaly's location in the YZ plane are the same as in the XZ plane.

[0122] As described above, the specific embodiments of this invention provide a wellbore full-space time-domain electromagnetic detection method. This method combines one or more transmitting modules and multiple receiving modules to form various measurement modes. Under different measurement modes, it acquires secondary electromagnetic field attenuation signals from multiple receiving modules. By analyzing the differences in the secondary electromagnetic field attenuation signals acquired from different receiving modules, the location of the target formation is identified. The wellbore full-space time-domain electromagnetic long-range detection method and device proposed in this invention have a simple structure and are easy to implement. They solve the problem of identifying the 360° azimuth of geological bodies in wellbore full-space time-domain electromagnetic detection, providing a solution for the engineering application of wellbore time-domain electromagnetic instruments.

[0123] Based on the same inventive concept, this application also provides a wellbore full-space time-domain electromagnetic detection device, which can be used to implement the method described in the above embodiments, as shown in the following embodiments. Since the principle of the wellbore full-space time-domain electromagnetic detection device in solving the problem is similar to that of the wellbore full-space time-domain electromagnetic detection method, the implementation of the wellbore full-space time-domain electromagnetic detection device can refer to the implementation of the wellbore full-space time-domain electromagnetic detection method, and repeated details will not be elaborated further. As used below, the terms "unit" or "module" can refer to a combination of software and / or hardware that implements a predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0124] The embodiments of the present invention provide a specific implementation of a wellbore full-space-time-domain electromagnetic detection device capable of realizing a wellbore full-space-time-domain electromagnetic detection method, wherein, see... Figure 13 A wellbore full-space time-domain electromagnetic detection device includes:

[0125] The primary field generation module 10 is used to transmit current pulses to the target formation through at least one transmitting module to generate a primary field;

[0126] The attenuation signal receiving module 20 is used to receive multiple secondary field attenuation signals through multiple receiving modules; wherein the secondary field attenuation signal is generated by the target stratum being excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance;

[0127] The target formation identification module 30 is used to identify the target formation based on the plurality of secondary field attenuation signals.

[0128] In some embodiments of the present invention, see Figure 14 A wellbore full-space time-domain electromagnetic detection device, further comprising:

[0129] Attenuation signal generation module 40 is used to generate the secondary field attenuation signal, see [link / reference]. Figure 15 The attenuation signal generation module 40 includes:

[0130] A current pulse interruption unit 40a is used to interrupt the current pulse;

[0131] The induced eddy current generating unit 40b is used to generate induced eddy currents in the target stratum through a primary field.

[0132] The attenuation signal generation unit 40c is used to generate the secondary field through the induced eddy current to generate the secondary field attenuation signal.

[0133] In some embodiments of the present invention, the transmitting module is a transmitting coil, and there is only one of them; the receiving module is a receiving coil.

[0134] The central axis of the transmitting coil and the central axis of the receiving coil coincide with the spindle of the time-domain electromagnetic detector, and the positions of the multiple receiving coils corresponding to the multiple receiving modules do not coincide in the time-domain electromagnetic detector.

[0135] In some embodiments of the present invention, the transmitting module is a transmitting coil, and there are multiple transmitting coils; the receiving module is a receiving coil; the transmitting coil and the receiving coil are elliptical in shape.

[0136] The coil plane of the transmitting coil forms a first acute angle with the spindle of the time-domain electromagnetic detector, and the coil planes of the other transmitting coils form a second acute angle with the spindle of the time-domain electromagnetic detector. The first acute angle and the second acute angle are complementary, and the coil centers of the multiple transmitting coils coincide.

[0137] The coil plane of the receiving coil forms the first acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other receiving coils forms the second acute angle with the spindle of the time-domain electromagnetic detector, and the coil centers of the multiple receiving coils coincide.

[0138] In some embodiments of the present invention, the transmitting module is a transmitting coil, and there are multiple transmitting coils; the receiving module is a receiving coil; the transmitting coil and the receiving coil are elliptical in shape.

[0139] The coil plane of the transmitting coil forms a third acute angle with the spindle of the time-domain electromagnetic detector, and the coil planes of the other transmitting coils form a first obtuse angle with the spindle of the time-domain electromagnetic detector. The first acute angle and the second acute angle are complementary, and the multiple transmitting coils are adjacent to each other in the position of the time-domain electromagnetic detector.

[0140] The coil plane of the receiving coil forms the third acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other transmitting coils forms the first obtuse angle with the spindle of the time-domain electromagnetic detector, and the plurality of receiving coils are adjacent to each other in the position of the time-domain electromagnetic detector.

[0141] In some embodiments of the present invention, see Figure 16 The target stratum identification module 30 includes:

[0142] The target formation identification unit 30a is used to identify the location of the target formation based on the intensity and magnitude relationship of the secondary field attenuation signals corresponding to multiple receiving modules measured by the time-domain electromagnetic probe as it moves in the wellbore.

[0143] As described above, embodiments of the present invention provide a borehole full-space time-domain electromagnetic detection device, comprising: a primary field generation module, used to transmit current pulses to a target formation through at least one transmitting module to generate a primary field; an attenuation signal receiving module, used to receive multiple secondary field attenuation signals through multiple receiving modules; wherein the secondary field attenuation signals are generated by the target formation being excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance; and a target formation identification module, used to identify resistivity anomalies in the target formation based on the multiple secondary field attenuation signals.

[0144] This invention utilizes one or more transmitting modules and multiple receiving modules positioned at different locations along the instrument axis. Through various combinations, multiple measurement modes are created, and secondary field attenuated electromagnetic signals from multiple receiving modules are acquired under different measurement modes. The differences in the acquired secondary field attenuated electromagnetic signals are then used to accurately identify the location of resistivity anomalies in the formation.

[0145] The embodiments of this application also provide a specific implementation of an electronic device capable of implementing all steps in the wellbore full-space time-domain electromagnetic detection method described in the above embodiments. See [link to relevant documentation]. Figure 17 The electronic devices specifically include the following:

[0146] Processor 1201, memory 1202, communications interface 1203, and bus 1204;

[0147] The processor 1201, memory 1202, and communication interface 1203 communicate with each other via bus 1204; the communication interface 1203 is used to realize information transmission between server-side devices and client-side devices and other related devices.

[0148] The processor 1201 is used to call the computer program in the memory 1202. When the processor executes the computer program, it implements all the steps in the wellbore full-space time-domain electromagnetic detection method in the above embodiments. For example, when the processor executes the computer program, it implements the following steps:

[0149] Step 100: Transmit a current pulse to the target formation through at least one transmitting module to generate a primary field;

[0150] Step 200: Receive multiple secondary field attenuation signals through multiple receiving modules; wherein the secondary field attenuation signals are generated by the target stratum being excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance;

[0151] Step 300: Identify the target formation based on the multiple secondary field attenuation signals.

[0152] Embodiments of this application also provide a computer-readable storage medium capable of implementing all steps of the wellbore full-space-time-domain electromagnetic detection method in the above embodiments. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements all steps of the wellbore full-space-time-domain electromagnetic detection method in the above embodiments. For example, when the processor executes the computer program, it implements the following steps:

[0153] Step 100: Transmit a current pulse to the target formation through at least one transmitting module to generate a primary field;

[0154] Step 200: Receive multiple secondary field attenuation signals through multiple receiving modules; wherein the secondary field attenuation signals are generated by the target stratum being excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance;

[0155] Step 300: Identify the target formation based on the multiple secondary field attenuation signals.

[0156] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. In particular, hardware + program embodiments are relatively simple in description because they are fundamentally similar to method embodiments; relevant parts can be referred to the descriptions in the method embodiments.

[0157] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0158] While this application provides method operation steps as shown in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-inventive labor. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only execution order. In actual device or client product execution, the method can be executed sequentially as shown in the embodiments or drawings, or in parallel (e.g., in a parallel processor or multi-threaded processing environment).

[0159] For ease of description, the above devices are described in terms of function, divided into various modules. Of course, in implementing the embodiments of this specification, the functions of each module can be implemented in one or more software and / or hardware components, or a module that performs the same function can be implemented by a combination of multiple sub-modules or sub-units. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between devices or units, and may be electrical, mechanical, or other forms.

[0160] Those skilled in the art will also know that, besides implementing the controller using purely computer-readable program code, the same functions can be achieved by logically programming the method steps, making the controller function as logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers (PLCs), and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the devices within it used to implement various functions can also be considered structures within that hardware component. Alternatively, the devices used to implement various functions can be considered as both software modules implementing the method and structures within a hardware component.

[0161] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0162] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0163] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, system embodiments are basically similar to method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. In the description of this specification, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments in this specification. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0164] The above description is merely an embodiment of the present specification and is not intended to limit the embodiments of the present specification. For those skilled in the art, various modifications and variations can be made to the embodiments of the present specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the embodiments of the present specification should be included within the scope of the claims of the embodiments of the present specification.

Claims

1. A method for full-space time-domain electromagnetic detection of wells, characterized in that, include: At least one transmitting module transmits a current pulse to the target formation to generate a primary field; Multiple secondary field attenuation signals are received by multiple receiving modules; wherein the secondary field attenuation signals are generated by the target stratum being excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance; The target formation is identified based on the multiple secondary field attenuation signals.

2. The borehole full-space time-domain electromagnetic detection method according to claim 1, characterized in that, The steps for generating the secondary field attenuation signal include: Cut off the current pulse; Induced eddy currents are generated in the target stratum through a primary field; The secondary field is generated by the induced eddy current to produce the secondary field attenuation signal.

3. The borehole full-space time-domain electromagnetic detection method according to claim 1, characterized in that, The transmitting module is a transmitting coil, and there is only one of them; the receiving module is a receiving coil. The central axis of the transmitting coil and the central axis of the receiving coil coincide with the spindle of the time-domain electromagnetic detector, and the positions of the multiple receiving coils corresponding to the multiple receiving modules do not coincide in the time-domain electromagnetic detector.

4. The borehole full-space time-domain electromagnetic detection method according to claim 1, characterized in that, The transmitting module is a transmitting coil, and there are multiple transmitting coils; the receiving module is a receiving coil; the transmitting coil and the receiving coil are elliptical in shape. The coil plane of the transmitting coil forms a first acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other transmitting coils forms a second acute angle with the spindle of the time-domain electromagnetic detector. The first acute angle and the second acute angle are complementary, and the coil centers of the multiple transmitting coils coincide. The coil plane of the receiving coil forms the first acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other receiving coils forms the second acute angle with the spindle of the time-domain electromagnetic detector, and the coil centers of the multiple receiving coils coincide.

5. The borehole full-space time-domain electromagnetic detection method according to claim 1, characterized in that, The transmitting module is a transmitting coil, and there are multiple transmitting coils; the receiving module is a receiving coil; the transmitting coil and the receiving coil are elliptical in shape. The coil plane of the transmitting coil forms a third acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other transmitting coils forms a first obtuse angle with the spindle of the time-domain electromagnetic detector. The third acute angle and the first obtuse angle are complementary, and the multiple transmitting coils are adjacent to each other in the position of the time-domain electromagnetic detector. The coil plane of the receiving coil forms the third acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other receiving coils forms the first obtuse angle with the spindle of the time-domain electromagnetic detector, and the multiple receiving coils are adjacent to each other in the position of the time-domain electromagnetic detector.

6. The borehole full-space time-domain electromagnetic detection method according to any one of claims 1 to 5, characterized in that, Identifying the target formation based on the multiple secondary field attenuation signals includes: The location of the target formation is identified by measuring the intensity and magnitude relationship of the secondary field attenuation signals corresponding to multiple receiving modules as the time-domain electromagnetic probe moves in the wellbore.

7. A wellbore full-space time-domain electromagnetic detection device, characterized in that, include: A primary field generation module is used to transmit current pulses to the target formation through at least one transmitting module to generate a primary field; An attenuation signal receiving module is used to receive multiple secondary field attenuation signals through multiple receiving modules; wherein, the secondary field attenuation signal is generated by the resistivity anomaly in the target stratum being excited by the primary field, and the distance between the transmitting module and the receiving module is a preset distance; The target formation identification module is used to identify the target formation based on the multiple secondary field attenuation signals.

8. The wellbore full-space time-domain electromagnetic detection device according to claim 7, characterized in that, Also includes: Attenuation signal generation module, used to generate the secondary field attenuation signal, the attenuation signal generation module includes: A current pulse interruption unit is used to interrupt the current pulse; An inductive eddy current generating unit is used to generate inductive eddy currents in the target formation through a primary field. The attenuation signal generation unit is used to generate the secondary field through the induced eddy current to generate the secondary field attenuation signal.

9. The wellbore full-space time-domain electromagnetic detection device according to claim 7, characterized in that, The transmitting module is a transmitting coil, and there is only one of them; the receiving module is a receiving coil. The central axis of the transmitting coil and the central axis of the receiving coil coincide with the spindle of the time-domain electromagnetic detector, and the positions of the multiple receiving coils corresponding to the multiple receiving modules do not coincide in the time-domain electromagnetic detector.

10. The wellbore full-space time-domain electromagnetic detection device according to claim 7, characterized in that, The transmitting module is a transmitting coil, and there are multiple transmitting coils; the receiving module is a receiving coil; the transmitting coil and the receiving coil are elliptical in shape. The coil plane of the transmitting coil forms a first acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other transmitting coils forms a second acute angle with the spindle of the time-domain electromagnetic detector. The first acute angle and the second acute angle are complementary, and the coil centers of the multiple transmitting coils coincide. The coil plane of the receiving coil forms the first acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other receiving coils forms the second acute angle with the spindle of the time-domain electromagnetic detector, and the coil centers of the multiple receiving coils coincide.

11. The wellbore full-space time-domain electromagnetic detection device according to claim 7, characterized in that, The transmitting module is a transmitting coil, and there are multiple transmitting coils; the receiving module is a receiving coil; the transmitting coil and the receiving coil are elliptical in shape. The coil plane of the transmitting coil forms a third acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other transmitting coils forms a first obtuse angle with the spindle of the time-domain electromagnetic detector. The third acute angle and the first obtuse angle are complementary, and the multiple transmitting coils are adjacent to each other in the position of the time-domain electromagnetic detector. The coil plane of the receiving coil forms the third acute angle with the spindle of the time-domain electromagnetic detector, and the coil plane of the other receiving coils forms the first obtuse angle with the spindle of the time-domain electromagnetic detector, and the multiple receiving coils are adjacent to each other in the position of the time-domain electromagnetic detector.

12. The wellbore full-space time-domain electromagnetic detection device according to any one of claims 7 to 11, characterized in that, The target stratum identification module includes: The target formation identification unit is used to identify the location of the target formation based on the intensity and magnitude relationship of the secondary field attenuation signals corresponding to multiple receiving modules measured by the time-domain electromagnetic probe as it moves in the wellbore.

13. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the wellbore full-space time-domain electromagnetic detection method according to any one of claims 1 to 6.

14. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the wellbore full-space time-domain electromagnetic detection method according to any one of claims 1 to 6.

15. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the wellbore full-space time-domain electromagnetic detection method according to any one of claims 1 to 6.

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