Old well open hole section tracking identification method and device

Abstract

The invention relates to an old well open hole section tracking and identifying method and device. The old well open hole section tracking and identifying method comprises the steps that a rescue well is drilled till the rescue well is communicated with an open hole section of an old well; determining a reference position in the old well, and taking the reference position as an initial position for tracking and identifying an open hole section of the old well; an ultrasonic detection positioning device is put into the old well to the initial position; the ultrasonic detection positioning device carries out ultrasonic detection in the circumferential direction of the rescue well from the initial position, and an ultrasonic detection result is obtained; wherein the ultrasonic detection result comprises the identified position of the sediment in the old well, and / or the position of the original stratum, and / or the junction position between the sediment in the old well and the original stratum; and according to the ultrasonic detection result, the drilling direction of the rescue well is adjusted, so that the drilling direction of the rescue well faces the old well or is kept consistent with the extending direction of the old well. According to the invention, the technical problem that the accuracy of tracking and identifying the borehole trajectory of the open hole section of the old well is poor is solved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas reservoir engineering technology, and further to a method and apparatus for tracking and identifying open-hole sections of old wells, particularly a method and apparatus for tracking and identifying open-hole sections of old wells based on ultrasonic detection and positioning. Background Technology

[0002] Gas storage facilities play an increasingly important role in strategic reserves and seasonal peak shaving of natural gas resources. During the conversion of depleted oil and gas reservoirs into gas storage facilities, some complex old wells require effective sealing to ensure the safe operation of the storage facility in its later stages.

[0003] Currently, a technology for re-entering old wells, primarily based on magnetic guidance, has been developed. This technology captures the magnetic signal of the casing inside the old wellbore to determine its location, thereby enabling re-entry and sealing. However, for some open-hole wells (i.e., well sections without casing), the wellbore is already compacted by accumulated rock cuttings and collapsed well walls. Although the old wellbore is filled with material, it lacks good sealing properties. Failure to re-enter and seal these old, buried wellbores will inevitably pose significant safety hazards to the later operation of the gas storage facility. To achieve efficient sealing, when re-drilling into the old wellbore, it is necessary to ensure that the new drilled well falls within the area of ​​the old wellbore and to drill along the old wellbore for a certain distance to reopen it and provide conditions for subsequent sealing operations. Currently, only naked-eye discrimination can be used to infer the wellbore trajectory of the open-hole section of the old well based on reasonable inference and experience. However, this method has poor accuracy and cannot perform high-precision tracking and identification of the open-hole section of the old well, which increases the difficulty of construction and reduces construction efficiency.

[0004] There is currently no effective solution to the problem of poor accuracy in tracking and identifying wellbore trajectories in open-hole sections of old wells in related technologies.

[0005] Therefore, based on years of experience and practice in related industries, the inventor proposes a naked-eye segment tracking and identification method and device for old wells to overcome the shortcomings of existing technologies. Summary of the Invention

[0006] The purpose of this invention is to provide a method and apparatus for tracking and identifying open hole sections in old wells. It uses ultrasonic scanning detection to accurately identify the relative positions of sediments and original strata within the open hole section of an old well, as well as the boundary between them. This allows for precise tracking and identification of the open hole section of the old well, ultimately enabling re-entry and sealing of the open hole section.

[0007] The objective of this invention can be achieved through the following methods:

[0008] This invention provides a method for tracking and identifying the open hole section of an old well, which involves reopening an old well that has been filled with sediment using a rescue well. The method includes the following steps:

[0009] Drill into the rescue well until it connects with the open-hole section of the old well;

[0010] A reference position is determined within the old well, and this reference position is used as the starting position for naked-eye segment tracking and identification of the old well.

[0011] An ultrasonic detection and positioning device is lowered into the old well to the starting position.

[0012] Starting from the aforementioned starting position, the ultrasonic detection and positioning device performs ultrasonic detection along the circumference of the rescue well and obtains ultrasonic detection results; wherein, the ultrasonic detection results include the location of the sediment in the old well, and / or the location of the original stratum, and / or the boundary between the sediment in the old well and the original stratum.

[0013] Based on the ultrasonic detection results, the drilling direction of the rescue well is adjusted so that the drilling direction of the rescue well is aligned with the old well or consistent with the extension direction of the old well.

[0014] In a preferred embodiment of the present invention, after adjusting the drilling direction of the rescue well, the method further includes:

[0015] The section of the rescue well drilled to the bottom or near the bottom coincides with the open-hole section of the old well and is located in the target formation;

[0016] The open-hole section of the old well was sealed using the rescue well.

[0017] In a preferred embodiment of the present invention, the starting position is the bottom of the fish that fell into the old well or the location of the casing shoe on the upper part of the bare eye section of the old well.

[0018] In a preferred embodiment of the present invention, the starting drilling position of the rescue well is located at a different position from that of the old well, and a magnetic guidance device is used to guide the rescue well to connect with the open hole section of the old well.

[0019] In a preferred embodiment of the present invention, if the ultrasonic detection result is that the location of the sediment in the old well and the boundary between the sediment in the old well and the original stratum are detected along the circumference of the rescue well, then the open hole sections of the rescue well and the old well completely coincide, and the rescue well continues to drill along the extension direction of the old well.

[0020] In a preferred embodiment of the present invention, if the ultrasonic detection result is that, along the circumference of the rescue well, one side is the location of the sediment in the old well, and the other side is the original stratum, and only one side detects the boundary between the sediment in the old well and the original stratum, then the open-hole section of the rescue well and the old well partially overlap, and the rescue well is adjusted to deflect towards the side where the sediment in the old well is located.

[0021] In a preferred embodiment of the present invention, if the ultrasonic detection result is that the original stratum is detected along the circumference of the rescue well, and the boundary between the sediment in the old well and the original stratum is detected only on one side, then the open-hole section of the rescue well is partially deviated from the open-hole section of the old well and there is no overlap between the two sections. The rescue well is then adjusted to deflect towards the side of the boundary between the sediment in the old well and the original stratum.

[0022] In a preferred embodiment of the present invention, obtaining the ultrasonic detection result includes:

[0023] Based on the echo signal of the emitted ultrasonic wave, an echo signal processing model is established;

[0024] Based on the echo signal processing model, identify the characteristic data of the actual echo signal;

[0025] Based on the aforementioned characteristic data, the lithological characteristics of the detected strata are identified to determine whether the detected strata are the location of the sediments in the old well, the location of the original strata, or the boundary between the sediments in the old well and the original strata.

[0026] In a preferred embodiment of the present invention, the echo signal processing model includes:

[0027] The distance between the ultrasonic detection and positioning device and the target location is obtained based on the time difference between the emitted ultrasonic signal and the received echo signal.

[0028] The acoustic impedance value of the detected stratum is obtained based on the sound pressure amplitude of the emitted ultrasonic signal, the sound pressure amplitude of the received echo signal, and the distance between the ultrasonic detection and positioning device and the target location.

[0029] Based on the acoustic impedance value of the detected strata, the lithological characteristics of the detected strata are identified.

[0030] In a preferred embodiment of the present invention, obtaining the distance between the ultrasonic detection and positioning device and the target location based on the time difference between the emitted ultrasonic signal and the received echo signal includes:

[0031] The echo signal is transformed from a time-domain signal to a frequency-domain signal;

[0032] Based on the frequency of the echo signal and the frequency of the emitted ultrasonic signal, the frequency variation coefficient between the two is obtained;

[0033] The lithological characteristics of the detected strata are quantified based on the acoustic impedance of the detected strata and the frequency variation coefficient between the frequency of the echo signal and the frequency of the emitted ultrasonic signal.

[0034] This invention provides a device for tracking and identifying open-hole sections of old wells, used to implement the above-described method for tracking and identifying open-hole sections of old wells. The device includes:

[0035] An ultrasonic detection and positioning device is lowered into the rescue well. The ultrasonic detection and positioning device is used to perform ultrasonic detection on the periphery of the rescue well and obtain ultrasonic detection results. The ultrasonic detection results include the location of the sediment in the old well, and / or the location of the original strata, and / or the boundary between the sediment in the old well and the original strata.

[0036] A ground-based data acquisition device is provided, wherein the signal receiving end of the data acquisition device is electrically connected to the signal output end of the ultrasonic detection and positioning device via a communication cable, and the data acquisition device is used to receive the ultrasonic detection results.

[0037] In a preferred embodiment of the present invention, the old well open hole section tracking and identification device further includes a magnetic guiding device. The magnetic guiding device is electrically connected to the data acquisition device through the communication cable. The magnetic guiding device is used to detect the position of the old well casing located above the open hole section of the old well and guide the rescue well to drill to communicate with the open hole section of the old well.

[0038] In a preferred embodiment of the present invention, the ultrasonic detection and positioning device includes a communication section, an orientation section, a steering drive section, and an ultrasonic probe connected in sequence. A communication device is installed within the communication section, and the signal output terminal of the communication device is electrically connected to the signal receiving terminal of the data acquisition device via a communication cable. A gyroscope is installed within the orientation section, and the signal output terminal of the gyroscope is electrically connected to the signal receiving terminal of the data acquisition device via the communication cable. A drive motor is installed within the steering drive section, and the output shaft of the drive motor is connected to the ultrasonic probe to drive the ultrasonic probe to rotate circumferentially along the rescue well.

[0039] In a preferred embodiment of the present invention, a storage section is connected between the communication section and the orientation section, and a data memory is provided in the storage section. The data memory is used to store the orientation data detected by the gyroscope, the ultrasonic signal data emitted by the ultrasonic probe, and the received echo signal data.

[0040] Based on the above, the features and advantages of the old well naked-eye segment tracking and identification method and device of the present invention are as follows:

[0041] Drill the rescue well until it connects with the open hole section of the old well. Establish a reference position within the old well, using this reference position as the starting point for tracking and identifying the open hole section of the old well. Run an ultrasonic detection and positioning device from the rescue well to its starting position within the old well. While drilling the rescue well from this starting position, the ultrasonic detection and positioning device performs ultrasonic detection along the circumference of the rescue well. Because the sediments in the old well have different acoustic impedances than the original formation, the location of the sediments, the original formation, and the boundary between them can be identified based on the ultrasonic detection results. This allows for the determination of the relative position between the rescue well and the open hole section of the old well. Depending on the relative position, the drilling direction of the rescue well can be adjusted to either face the old well or align with its extension direction. This guides the drill bit to continuously track the open hole section of the old well until the rescue well reaches the target formation, where effective sealing of the open hole section of the old well is performed to ensure the integrity of the gas storage tank's seal. Attached Figure Description

[0042] The accompanying drawings are intended only to illustrate and explain the present invention and do not limit the scope of the invention.

[0043] in:

[0044] Figure 1 This is one of the flowcharts for the naked-eye segment tracking and identification method of old wells in this invention.

[0045] Figure 2 This is the second flowchart of the old well naked-eye segment tracking and identification method of the present invention.

[0046] Figure 3 This is the third flowchart of the old well naked-eye segment tracking and identification method of the present invention.

[0047] Figure 4 This is a schematic diagram of the structure in the old well open-hole section tracking and identification method of the present invention, in which a magnetic guiding device guides the drilling of the rescue well to connect with the old well.

[0048] Figure 5 This is one of the schematic diagrams illustrating the positional relationship between the open-hole sections of the rescue well and the old well in the open-hole section tracking and identification method of the old well of the present invention.

[0049] Figure 6 This is the second schematic diagram illustrating the positional relationship between the rescue well and the open-hole section of the old well in the old well open-hole section tracking and identification method of the present invention.

[0050] Figure 7 This is the third schematic diagram illustrating the positional relationship between the open-hole sections of the rescue well and the old well in the open-hole section tracking and identification method of the old well of the present invention.

[0051] Figure 8 This is a schematic diagram of the ultrasonic detection and positioning device in the old well naked-eye section tracking and identification device of the present invention.

[0052] Figure 9 The image shows waveforms of the echo signals of the original formation and the sediments in the old well, collected by the ultrasonic detection and positioning device in the old well open-hole section tracking and identification device of this invention.

[0053] The reference numerals in the accompanying drawings of this invention are:

[0054] 1. Data acquisition device; 2. Communication cable;

[0055] 3. The open-hole section of the old well; 4. The rescue well;

[0056] 5. Original strata; 6. Old well casing;

[0057] 7. Fish falling into the water; 8. Ultrasonic detection and positioning device;

[0058] 801. Communication section; 802. Storage section;

[0059] 803. Directional sub; 804. Connecting sub;

[0060] 805. Steering drive short joint; 806. Ultrasonic probe;

[0061] 9. Magnetic guidance device; 10. Reference position. Detailed Implementation

[0062] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0063] Implementation Method 1

[0064] like Figures 1 to 9 As shown, this invention provides a method for tracking and identifying open-hole sections of old wells. The method involves reopening an old well that has been filled with sediment using a rescue well (4). The method includes the following steps:

[0065] Step S1: Drill rescue well 4 until it connects with the open hole section 3 of the old well;

[0066] Furthermore, such as Figures 4 to 7 As shown, the initial drilling position of rescue well 4 is different from that of the old well. Before rescue well 4 connects with the open hole section 3 of the old well, a magnetic steering device 9 can be used to guide rescue well 4 to connect with the open hole section 3 of the old well. Since there is an old well casing 6 above the open hole section 3 of the old well, the magnetic steering device 9 can be used to determine the orientation of the old well by capturing the magnetic signal of the old well casing 6, thereby enabling the drilling of rescue well 4. The magnetic steering device 9 can be, but is not limited to, existing MGD magnetic steering drilling equipment for precise navigation drilling, or other equipment capable of detecting magnetic signals; specific equipment is not specifically limited here.

[0067] During the above process, the magnetic guidance device 9 detects and identifies the location of the old well casing 6 and the downhole fish 7 while the rescue well 4 is being drilled, and guides the rescue well 4 to drill to the bottom of the downhole fish 7 in the old well or to the location of the casing shoe located on the upper part of the open hole section 3 of the old well, so that the rescue well 4 can be connected to the open hole section 3 of the old well.

[0068] Step S2: Determine the reference position 10 inside the old well, and use the reference position 10 as the starting position for tracking and identifying the naked eye segment 3 of the old well;

[0069] The starting position can be the bottom of the fish 7 in the old well or the location of the casing shoe on the upper part of the open section 3 of the old well (i.e., below the casing 6 of the old well). The above position is the starting position of the open section 3 of the old well. Therefore, the above position can be used as the starting position for the next step of ultrasonic detection and tracking identification to ensure that the open section 3 of the old well is completely tracked and identified as a whole.

[0070] Step S3: Lower the ultrasonic detection and positioning device 8 into the old well to the starting position;

[0071] Step S4: Starting from the initial position, the ultrasonic detection and positioning device 8 performs ultrasonic detection along the circumference of the rescue well 4 and obtains the ultrasonic detection results; wherein, the ultrasonic detection results include the location of the sediment in the old well, and / or the location of the original stratum 5, and / or the boundary between the sediment in the old well and the original stratum 5.

[0072] Step S5: Based on the ultrasonic detection results, adjust the drilling direction of rescue well 4 so that the drilling direction of rescue well 4 is aligned with the old well or consistent with the extension direction of the old well, so that rescue well 4 can be restored to a drilling direction consistent with the extension direction of the open hole section 3 of the old well.

[0073] Step S6: Drill the bottom or near the bottom of the rescue well 4 so that it overlaps with the open hole section 3 of the old well and is located in the target formation;

[0074] Step S7: Use rescue well 4 to seal the open hole section 3 of the old well.

[0075] In this invention, the rescue well 4 is drilled until it connects with the open hole section 3 of the old well. A reference position 10 is determined within the old well, and this reference position 10 serves as the starting position for tracking and identifying the open hole section 3 of the old well. An ultrasonic detection and positioning device 8 is lowered into the rescue well 4 until it reaches its starting position within the old well. Simultaneously with drilling the rescue well 4 from this starting position, the ultrasonic detection and positioning device 8 performs ultrasonic detection along the circumference of the rescue well 4. Because the sediments within the old well have different acoustic impedances than the original strata 5, the location of the sediments within the old well can be identified based on the ultrasonic detection results. The location of the original stratum 5 and the boundary between the sediments in the old well and the original stratum 5 are determined, thereby obtaining the relative position between the rescue well 4 and the open hole section 3 of the old well. Based on the different relative positions of the rescue well 4 and the open hole section 3 of the old well, the drilling direction of the rescue well 4 can be adjusted so that the drilling direction of the rescue well 4 is towards the open hole section 3 of the old well or consistent with the extension direction of the open hole section 3 of the old well. This achieves the purpose of guiding the drill bit to continuously track the drilling of the open hole section 3 of the old well until the rescue well 4 reaches the target stratum and performs effective sealing operations on the open hole section 3 of the old well, ensuring the sealing integrity of the gas storage.

[0076] During ultrasonic detection, the results can identify the location of sediments in the old well, the location of the original stratum 5, and the boundary between the sediments in the old well and the original stratum 5. Based on different ultrasonic detection results, the location of the original stratum 5 and the open hole section 3 of the old well, as well as the boundary between them, can be accurately identified and distinguished. When the relative positions of the rescue well 4 and the open hole section 3 of the old well are completely coincident, the rescue well 4 continues to drill along the extension direction of the old well without needing to adjust its drilling direction. When the relative positions of the rescue well 4 and the open hole section 3 of the old well are partially coincident or not coincident at all, the drilling direction of the rescue well 4 needs to be adjusted towards the open hole section 3 of the old well to guide the drill bit to continuously track the drilling of the open hole section 3 of the old well, ensuring the effective sealing operation of the open hole section 3 of the old well.

[0077] In an optional embodiment of the present invention, such as Figure 5As shown, if the ultrasonic detection results indicate the location of sediments in the old well and the boundary between the sediments in the old well and the original stratum 5 along the circumference of the rescue well 4, then the rescue well 4 completely overlaps with the open hole section 3 of the old well (i.e., the rescue well 4 falls entirely within the open hole section 3 of the old well), and the rescue well 4 continues drilling along the extension direction of the open hole section 3 of the old well. Under this condition, the ultrasonic detection results show that the rocks identified around the well are all sediments from the old well, and there is a clear boundary between the original stratum 5 and the open hole section 3 of the old well around the well. The rescue well 4 can then continue drilling along the predetermined trajectory without needing to adjust its drilling direction.

[0078] In another alternative embodiment of the invention, such as Figure 6 As shown, if the ultrasonic detection results indicate that along the circumference of rescue well 4, one side detects the location of sediments in the old well, and the opposite side detects the original stratum 5, and only one side detects the boundary between the sediments in the old well and the original stratum 5, then rescue well 4 partially overlaps with the open hole section 3 of the old well (i.e., part of rescue well 4 falls within the open hole section 3 of the old well). In this case, rescue well 4 should be adjusted to deflect towards the side where the sediments in the old well are located. Under these conditions, the ultrasonic detection results show that the rock identified on one side of the well is sediments in the old well, and the rock identified on the other side is the original stratum 5. Only one side can identify the interface between the original stratum 5 and the open hole section 3 of the old well. Therefore, based on the identified sediments in the old well, the original stratum 5, and the interface between the original stratum 5 and the open hole section 3 of the old well, the subsequent drilling direction of rescue well 4 needs to be adjusted to correct its drilling trajectory, causing rescue well 4 to drill towards the interior of the open hole section 3 of the old well.

[0079] In another alternative embodiment of the invention, such as Figure 7 As shown, if the ultrasonic detection results indicate that the original stratum 5 is detected along the circumference of the rescue well 4, and only one side detects the boundary between the sediment in the old well and the original stratum 5, then the rescue well 4 is partially deviated from the open hole section 3 of the old well and there is no overlap between them. The rescue well 4 should be adjusted to deflect towards the boundary between the sediment in the old well and the original stratum 5. In this condition, the ultrasonic detection results indicate that all rocks identified around the well are the original stratum 5, and only one side can identify the interface between the original stratum 5 and the open hole section 3 of the old well. At this point, the subsequent drilling direction of the rescue well 4 needs to be adjusted based on the identified interface between the original stratum 5 and the open hole section 3 of the old well, correcting the drilling trajectory of the rescue well 4 so that it drills towards the open hole section 3 of the old well.

[0080] Because the medium through which ultrasonic signals are transmitted between the sediments in the open-hole section 3 of the old well and the original stratum 5 is different, and the reflection characteristics of the two media for the same ultrasonic signal are different, such as... Figure 9 As shown, the amplitude of the echo signal of the original stratum 5 is significantly higher than the amplitude of the echo signal of the sediment in the open hole section 3 of the old well. In this invention, the ultrasonic detection and positioning is also based on this characteristic phenomenon to accurately identify and distinguish the original stratum 5, the open hole section 3 of the old well, and the interface between the two.

[0081] During the implementation of this invention, due to the complex working conditions inside the rescue well 4, the echo signal of the ultrasonic wave is affected by many factors. In order to more accurately identify and judge the characteristic data of the echo signal, and thus identify the lithology of the target stratum, in an optional embodiment of this invention, an echo signal processing model can be established to improve the accuracy of echo signal identification.

[0082] In this embodiment, as Figure 2 As shown, obtaining the ultrasonic detection result (i.e., step S5) includes:

[0083] Step S501: Establish an echo signal processing model based on the echo signal of the emitted ultrasonic wave;

[0084] Step S502: Identify the characteristic data of the actual echo signal based on the echo signal processing model;

[0085] Step S503: Based on the feature data, identify the lithological characteristics of the detected strata to determine whether the detected strata are the location of sediments in the old well, the location of the original strata, or the boundary between sediments in the old well and the original strata.

[0086] Furthermore, the echo signal processing model in step S501 includes:

[0087] Step S5011: Based on the time difference between the emitted ultrasonic signal and the received echo signal, obtain the distance between the ultrasonic detection and positioning device and the target location.

[0088] The distance between the ultrasonic detection and positioning device and the target location satisfies the following condition:

[0089]

[0090] Where L is the distance between the ultrasonic detection and positioning device and the target location; Δt is the time difference between the emission of the ultrasonic signal and the reception of the echo signal; and v is the propagation speed of the ultrasonic wave.

[0091] Step S5012: Obtain the acoustic impedance value of the detected stratum based on the sound pressure amplitude of the emitted ultrasonic signal, the sound pressure amplitude of the received echo signal, and the distance between the ultrasonic detection and positioning device and the target location.

[0092] Starting from the ultrasonic detection and positioning device 8 emitting an ultrasonic signal, the ultrasonic signal propagates through the distance L between the ultrasonic detection and positioning device and the target location to the detection target (original formation 5 or the open hole section 3 of an old well). After reaching the detection target (original formation 5 or the open hole section 3 of an old well), a portion of the ultrasonic signal is reflected back by the detection target (i.e., the echo signal). The echo signal then returns to the ultrasonic detection and positioning device 8 through the same distance L and is received. During the above process of ultrasonic signal emission and echo signal reception, the following conditions are met:

[0093]

[0094] Among them, P S It is the sound pressure amplitude P of the ultrasonic signal emitted by the ultrasonic detection and positioning device at the initial moment. e Z is the sound pressure amplitude of the echo signal received by the ultrasonic detection and positioning device at the end of the transmission, α is the signal attenuation coefficient of the ultrasonic signal as it propagates in the medium and varies with the propagation distance. r It is the acoustic impedance of the target (sediments in the original strata or the open hole section of an old well), Z w It is the acoustic impedance of the working fluid inside the well.

[0095] Furthermore, the above sound pressure amplitude can be calculated using the sensitivity of the ultrasonic transducer, as follows:

[0096]

[0097] Among them, VV S It is the excitation voltage of the ultrasonic transducer when the ultrasonic detection and positioning device emits an ultrasonic signal, VV e It is the voltage excited by the echo signal when the ultrasonic detection and positioning device receives the echo signal, and μ is the sensitivity of the ultrasonic transducer (i.e., the voltage value that can be excited in the ultrasonic transducer per unit sound pressure value).

[0098] By combining the above formulas (1), (2), (3), and (4), the acoustic impedance of the target can be calculated.

[0099] Step S5013: Identify the lithological characteristics of the probed strata based on the acoustic impedance value of the probed strata (i.e., the target location).

[0100] In an optional embodiment of the present invention, during the process of acquiring the acoustic impedance value of the probe formation, due to the presence of impurities (such as rock cuttings, air bubbles, etc.) in the working fluid inside the well, and the changes in the well temperature and density of the working fluid, it is necessary to correct the signal attenuation coefficient α.

[0101] α c =α×γ(m,T,ρ···) (5)

[0102] Where, α c ρ is the corrected signal attenuation coefficient, m is the composition of the working fluid in the well, T is the temperature in the well, and ρ is the density of the working fluid in the well.

[0103] In an optional embodiment of the present invention, step S5011 includes:

[0104] Step S50111: The echo signal can be transformed and processed to transform the echo signal from a time domain signal to a frequency domain signal;

[0105] The echo signal is transformed from a time-domain signal to a frequency-domain signal as follows:

[0106] F(w)=∫f(t)e (-jwt) dt (6)

[0107] Where F(w) represents a complex function in the frequency domain, f(t) represents the time-domain sequence function of the ultrasonic signal, w represents the frequency, and e (-jwt) This represents a complex exponential function.

[0108] Step S50112: Obtain the frequency variation coefficient between the echo signal and the emitted ultrasonic signal based on their frequencies;

[0109] Specifically, the dominant frequency, denoted as fmain, can be calculated using the above formula (6). The coefficient of variation between the dominant frequency of the echo signal and the frequency of the emitted ultrasonic signal is as follows:

[0110] τ=τ(|f main -F S |) (7)

[0111] Among them, F S τ is the frequency of the ultrasonic signal emitted by the ultrasonic detection and positioning device at the initial moment, and τ is the coefficient of variation between the dominant frequency of the echo signal and the frequency of the emitted ultrasonic signal.

[0112] Step S50113: Based on the acoustic impedance of the probed strata and the frequency variation coefficient between the frequency of the echo signal and the frequency of the emitted ultrasonic signal, quantify the lithological characteristics of the probed strata: θ=θ(Z r ,τ).

[0113] The features and advantages of the naked-eye segment tracking and identification method for old wells of the present invention are as follows:

[0114] The old well open-hole section tracking and identification method, based on the difference in lithology between the sediments in the old well and the original stratum 5, uses ultrasonic detection to identify at least the location of the sediments in the old well, the location of the original stratum 5, and the boundary between the sediments in the old well and the original stratum 5. This allows for the determination of the relative position between the rescue well 4 and the open-hole section 3 of the old well. Based on the different relative positions of the rescue well 4 and the open-hole section 3 of the old well, the drilling direction of the rescue well 4 can be adjusted to guide the drill bit to continuously track the open-hole section 3 of the old well until the rescue well 4 reaches the target stratum, where effective sealing operations can be carried out on the open-hole section 3 of the old well, ensuring the sealing integrity of the gas storage facility.

[0115] Implementation Method 2

[0116] like Figures 4 to 8 As shown, this invention provides a tracking and identification device for open-hole sections of old wells, used to implement the aforementioned tracking and identification method for open-hole sections of old wells. The device includes an ultrasonic detection and positioning device 8 lowered into the rescue well 4 and a data acquisition device 1 located on the ground. The ultrasonic detection and positioning device 8 performs ultrasonic detection on the periphery of the rescue well 4 and obtains the ultrasonic detection results. These results include the identified location of sediments within the old well, and / or the location of the original stratum 5, and / or the boundary between the sediments within the old well and the original stratum 5. The signal receiving end of the data acquisition device 1 is electrically connected to the signal output end of the ultrasonic detection and positioning device 8 via a communication cable 2, and the data acquisition device 1 receives the ultrasonic detection results. Both the ultrasonic signals emitted by the ultrasonic detection and positioning device 8 and the received echo signals can be transmitted to the data acquisition device 1 for data reception and storage, ensuring accurate tracking and identification of the open-hole section 3 of the old well.

[0117] Among them, the communication cable 2 can be, but is not limited to, a cable.

[0118] In an optional embodiment of the invention, such as Figure 4 As shown, the old well open-hole section tracking and identification device also includes a magnetic guidance device 9. The magnetic guidance device 9 is electrically connected to the data acquisition device 1 via a communication cable 2. The magnetic guidance device 9 is used to detect the position of the old well casing 6 located above the old well open-hole section and guide the rescue well drilling to connect with the old well open-hole section. Since the old well casing 6 is located above the old well open-hole section 3 within the old well, before drilling the rescue well 4 to connect with the old well open-hole section 3, the magnetic guidance device 9 can capture the magnetic signal of the old well casing 6 to determine the orientation of the old well and transmit the data to the data acquisition device 1, thereby enabling the drilling of the rescue well 4. The magnetic guidance device 9 can use, but is not limited to, existing MGD magnetic steerable drilling equipment for precise navigation drilling.

[0119] In an optional embodiment of the present invention, such as Figure 8 As shown, the ultrasonic detection and positioning device 8 includes a communication subsection 801, a directional subsection 803, a steering drive subsection 805, and an ultrasonic probe 806 connected in sequence. The communication subsection 801 houses a communication device, whose signal output is electrically connected to the signal receiver of the data acquisition device 1 via a communication cable 2. The directional subsection 803 houses a gyroscope, whose signal output is also electrically connected to the signal receiver of the data acquisition device 1 via the communication cable 2. The gyroscope can detect the orientation of the ultrasonic probe 806 in real time, ensuring accurate monitoring of the drilling and adjustment direction of the rescue well 4. The steering drive subsection 805 houses a drive motor, whose output shaft is connected to the ultrasonic probe 806, driving the ultrasonic probe 806 to rotate circumferentially around the rescue well 4, thus enabling omnidirectional detection along the circumference of the rescue well 4.

[0120] Furthermore, such as Figure 8 As shown, a storage section 802 is connected between the communication section 801 and the orientation section 803. A data memory is provided inside the storage section 802. The signal receiving end of the data memory is electrically connected to the signal output end of the gyroscope and the signal output end of the ultrasonic probe 806. The data memory is used to store the orientation data detected by the gyroscope, the ultrasonic signal data emitted by the ultrasonic probe 806, and the received echo signal data.

[0121] Furthermore, such as Figure 8 As shown, a connecting section 804 is provided between the directional section 803 and the steering drive section 805. The two ends of the connecting section 804 are fixedly connected to the directional section 803 and the steering drive section 805 respectively, or are rotatably connected to them, so as to realize the connection between the directional section 803 and the steering drive section 805.

[0122] The old well naked-eye section tracking and identification device of the present invention has the same features and advantages as the above-mentioned old well naked-eye section tracking and identification method, which will not be repeated here.

[0123] The above description is merely an illustrative embodiment of the present invention and is not intended to limit the scope of the invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for tracking and identifying the open-hole section of an old well, characterized in that: The method for tracking and identifying the bare-eye section of an old well includes the following steps: Drill into the rescue well until it connects with the open-hole section of the old well; A reference position is determined within the old well, and this reference position is used as the starting position for naked-eye segment tracking and identification of the old well. An ultrasonic detection and positioning device is lowered into the old well to the starting position. Starting from the aforementioned starting position, the ultrasonic detection and positioning device performs ultrasonic detection along the circumference of the rescue well and obtains ultrasonic detection results; wherein, the ultrasonic detection results include the location of the sediment in the old well, and / or the location of the original stratum, and / or the boundary between the sediment in the old well and the original stratum. Based on the ultrasonic detection results, the drilling direction of the rescue well is adjusted so that the drilling direction of the rescue well is aligned with the old well or consistent with the extension direction of the old well.

2. The method for tracking and identifying the bare-hole section of an old well as described in claim 1, characterized in that, After adjusting the drilling direction of the rescue well, the method further includes: The section of the rescue well drilled to the bottom or near the bottom coincides with the open-hole section of the old well and is located in the target formation; The open-hole section of the old well was sealed using the rescue well.

3. The method for tracking and identifying the bare-hole section of an old well as described in claim 1, characterized in that, The starting position is the location of the bottom of the old well where the fish fell or the location of the sleeve shoe on the upper part of the bare eye section of the old well.

4. The method for tracking and identifying the bare-hole section of an old well as described in claim 3, characterized in that, The starting drilling position of the rescue well is different from that of the old well. A magnetic guide device is used to guide the rescue well to connect with the open hole section of the old well.

5. The method for tracking and identifying the bare-hole section of an old well as described in claim 1, characterized in that, If the ultrasonic detection results indicate that the location of the sediment in the old well and the boundary between the sediment in the old well and the original stratum are detected along the circumference of the rescue well, then the open-hole sections of the rescue well and the old well completely overlap, and the rescue well continues drilling along the extension direction of the old well.

6. The method for tracking and identifying the bare-eye section of an old well as described in claim 1, characterized in that, If the ultrasonic detection results show that, along the circumference of the rescue well, one side is the location of sediment in the old well, and the other side is the original stratum, and only one side detects the boundary between the sediment in the old well and the original stratum, then the open-hole section of the rescue well and the old well partially overlap, and the rescue well is adjusted to deflect towards the side where the sediment in the old well is located.

7. The method for tracking and identifying the bare-hole section of an old well as described in claim 1, characterized in that, If the ultrasonic detection result indicates that the original stratum is detected along the circumference of the rescue well, and the boundary between the sediment in the old well and the original stratum is detected only on one side, then the open-hole section of the rescue well is partially deviated from the open-hole section of the old well and there is no overlap between them. The rescue well is then adjusted to deflect towards the side of the boundary between the sediment in the old well and the original stratum.

8. The method for tracking and identifying the bare-hole section of an old well as described in claim 1, characterized in that, The method of obtaining ultrasonic detection results includes: Based on the echo signal of the emitted ultrasonic wave, an echo signal processing model is established; Based on the echo signal processing model, identify the characteristic data of the actual echo signal; Based on the aforementioned characteristic data, the lithological characteristics of the detected strata are identified to determine whether the detected strata are the location of the sediments in the old well, the location of the original strata, or the boundary between the sediments in the old well and the original strata.

9. The method for tracking and identifying the bare-hole section of an old well as described in claim 8, characterized in that, The echo signal processing model includes: The distance between the ultrasonic detection and positioning device and the target location is obtained based on the time difference between the emitted ultrasonic signal and the received echo signal. The acoustic impedance value of the detected stratum is obtained based on the sound pressure amplitude of the emitted ultrasonic signal, the sound pressure amplitude of the received echo signal, and the distance between the ultrasonic detection and positioning device and the target location. Based on the acoustic impedance value of the detected strata, the lithological characteristics of the detected strata are identified.

10. The method for tracking and identifying the bare-hole section of an old well as described in claim 9, characterized in that, The step of obtaining the distance between the ultrasonic detection and positioning device and the target location based on the time difference between the emitted ultrasonic signal and the received echo signal includes: The echo signal is transformed from a time-domain signal to a frequency-domain signal; Based on the frequency of the echo signal and the frequency of the emitted ultrasonic signal, the frequency variation coefficient between the two is obtained; The lithological characteristics of the detected strata are quantified based on the acoustic impedance of the detected strata and the frequency variation coefficient between the frequency of the echo signal and the frequency of the emitted ultrasonic signal.

11. A device for tracking and identifying open-hole sections of old wells, used to implement the method for tracking and identifying open-hole sections of old wells as described in any one of claims 1 to 10, characterized in that, The old well open-hole section tracking and identification device includes: An ultrasonic detection and positioning device is lowered into the rescue well. The ultrasonic detection and positioning device is used to perform ultrasonic detection on the periphery of the rescue well and obtain ultrasonic detection results. The ultrasonic detection results include the location of the sediment in the old well, and / or the location of the original strata, and / or the boundary between the sediment in the old well and the original strata. A ground-based data acquisition device is provided, wherein the signal receiving end of the data acquisition device is electrically connected to the signal output end of the ultrasonic detection and positioning device via a communication cable, and the data acquisition device is used to receive the ultrasonic detection results.

12. The old well open-hole section tracking and identification device as described in claim 11, characterized in that, The old well open hole section tracking and identification device also includes a magnetic guidance device. The magnetic guidance device is electrically connected to the data acquisition device through the communication cable. The magnetic guidance device is used to detect the position of the old well casing located above the old well open hole section and guide the rescue well to drill to connect with the old well open hole section.

13. The old well open-hole section tracking and identification device as described in claim 11, characterized in that, The ultrasonic detection and positioning device includes a communication section, an orientation section, a steering drive section, and an ultrasonic probe connected in sequence. The communication section contains a communication device, the signal output of which is electrically connected to the signal receiving end of the data acquisition device via a communication cable. The orientation section contains a gyroscope, the signal output of which is electrically connected to the signal receiving end of the data acquisition device via a communication cable. The steering drive section contains a drive motor, the output shaft of which is connected to the ultrasonic probe to drive the ultrasonic probe to rotate circumferentially along the rescue well.

14. The old well open-hole section tracking and identification device as described in claim 13, characterized in that, A storage section is connected between the communication section and the orientation section. The storage section contains a data memory for storing the orientation data detected by the gyroscope, the ultrasonic signal data emitted by the ultrasonic probe, and the received echo signal data.

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