Method and device for tracking and identifying open hole section of old well

Abstract

A method and device for tracking and identifying an open hole section of an old well. The method for tracking and identifying an open hole section of an old well comprises: drilling a relief hole (4) until the relief hole is communicated with an open hole section (3) of an old well; determining a reference position (10) in the old well, and using the reference position (10) as a starting position for tracking and identifying the open hole section (3) of the old well; lowering an ultrasonic detection and positioning device (8) to the starting position in the old well; from the starting position, the ultrasonic detection and positioning device (8) performing ultrasonic detection along the circumferential direction of the relief hole (4), and obtaining an ultrasonic detection result, wherein the ultrasonic detection result comprises the identified position of sediments in the old well, and / or the identified position of an original stratum, and / or the identified position of the boundary between the sediments in the old well and the original stratum; and adjusting the drilling direction of the relief hole (4) on the basis of the ultrasonic detection result, so that the drilling direction of the relief hole (4) faces the old well or is consistent with the extension direction of the old well.

Description

Old well open hole section tracking identification method and device thereof

[0001] Related Applications

[0002] The present application claims priority to the Chinese Patent Application No. 202410702963.X filed on May 31, 2024, and incorporates by reference the entire disclosure of the aforementioned patent application as part of the present application. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of oil and gas reservoir engineering, further relates to an old well open hole section tracking identification method and device thereof, and particularly relates to an old well open hole section tracking identification method and device thereof based on ultrasonic detection positioning. BACKGROUND

[0004] Gas storage can achieve strategic reserve and seasonal peak shaving of natural gas resources, and plays an increasingly important role. In the process of converting depleted oil and gas reservoirs into gas storage, some complex old wells need to be effectively plugged to ensure the safe operation of the gas storage in the later period.

[0005] At present, the old wellbore tracking re-entry technology mainly based on magnetic guidance has been formed. This technology captures the magnetic signal of the casing in the old wellbore, and then judges the direction of the old wellbore, so as to realize the re-entry and plugging of the old wellbore. However, for some open hole old wells (i.e. there is no casing in the well section), the wellbore has been compacted by the original cuttings and collapsed well wall, although the old wellbore has been filled with fillers, but it does not have good sealing performance itself. If these old buried wellbores are not re-entered and plugged, it will inevitably bring great safety hazards to the later operation of the gas storage. However, to achieve efficient plugging, when re-drilling into the old wellbore, it is necessary to ensure that the new wellbore falls within the range of the old wellbore, and a distance along the old wellbore needs to be drilled, so as to reopen the old wellbore and provide operation conditions for subsequent plugging. However, at present, only the open hole discrimination method can be used to infer the wellbore trajectory of the old well open hole section according to reasonable inference and experience discrimination, but the accuracy of this scheme is poor, and it is difficult to track and identify the old well open hole section with high precision, which increases the construction difficulty and reduces the construction efficiency.

[0006] In view of the problem of poor tracking and identification accuracy of the wellbore trajectory of the old well open hole section in the related art, an effective solution has not been given.

[0007] Therefore, the present inventors, based on years of experience and practice in the relevant industry, propose an old well open hole section tracking identification method and device to overcome the shortcomings of the prior art. SUMMARY

[0008] The present disclosure aims to provide a method and device for tracking and identifying a bare hole section of an old well, which adopts an ultrasonic scanning detection method to accurately identify the relative positions of deposits and original strata in the bare hole section of the old well and the interface position therebetween, thereby accurately tracking and identifying the bare hole section of the old well, and finally realizing re-entry plugging of the bare hole section of the old well.

[0009] The purpose of the present disclosure can be achieved by the following solutions:

[0010] The present disclosure provides a method for tracking and identifying a bare hole section of an old well, which reopens the old well filled with deposits by a relief well, and the method comprises the following steps:

[0011] Drilling the relief well to communicate with the bare hole section of the old well;

[0012] Determining a reference position in the old well, and taking the reference position as a starting position for tracking and identifying the bare hole section of the old well;

[0013] Lowering an ultrasonic detection and positioning device into the old well to the starting position;

[0014] From the starting position, the ultrasonic detection and positioning device performs ultrasonic detection along the circumference of the relief well and obtains an ultrasonic detection result; wherein the ultrasonic detection result includes the position of the deposits in the old well, and / or the position of the original strata, and / or the interface position between the deposits and the original strata in the old well;

[0015] According to the ultrasonic detection result, the drilling direction of the relief well is adjusted so that the drilling direction of the relief well is directed towards the old well or consistent with the extension direction of the old well.

[0016] In an optional embodiment of the present disclosure, after adjusting the drilling direction of the relief well, the method further comprises:

[0017] Drilling the bottom or the well section close to the bottom of the relief well to coincide with the bare hole section of the old well and be located in the target strata;

[0018] Performing plugging operation on the bare hole section of the old well through the relief well.

[0019] In an optional embodiment of the present disclosure, the starting position is the position of the fish dropping bottom in the old well or the position of the casing shoe at the upper part of the bare hole section of the old well.

[0020] In an optional embodiment of the present disclosure, the starting drilling position of the relief well is different from that of the old well, and a magnetic guide device is used to guide the drilling of the relief well to communicate with the bare hole section of the old well.

[0021] In an optional embodiment of the present disclosure, if the ultrasonic detection result is that the deposits in the old well are detected along the circumferential direction of the relief well, and the interface position between the deposits in the old well and the original stratum is detected, the open hole section of the relief well and the old well are completely coincident, and the relief well continues to drill along the extension direction of the old well.

[0022] In an optional embodiment of the present disclosure, if the ultrasonic detection result is that the deposits in the old well are detected along the circumferential direction of the relief well, and the interface position between the deposits in the old well and the original stratum is detected, the open hole section of the relief well and the old well are completely coincident, and the relief well continues to drill along the extension direction of the old well.

[0023] In an optional embodiment of the present disclosure, if the ultrasonic detection result is that the deposits in the old well are detected along the circumferential direction of the relief well, and the interface position between the deposits in the old well and the original stratum is detected, the open hole section of the relief well and the old well are completely coincident, and the relief well continues to drill along the extension direction of the old well.

[0024] In an optional embodiment of the present disclosure, the ultrasonic detection result is obtained, comprising:

[0025] According to the echo signal of the emitted ultrasonic wave, an echo signal processing model is established;

[0026] According to the echo signal processing model, the characteristic data of the actual echo signal are identified;

[0027] According to the characteristic data, the lithological feature of the detected stratum is identified to determine whether the detected stratum is the deposit position in the old well, the original stratum position or the interface position between the deposits in the old well and the original stratum.

[0028] In an optional embodiment of the present disclosure, the echo signal processing model comprises:

[0029] According to the time difference between the emitted ultrasonic signal and the received echo signal, the distance between the ultrasonic detection positioning device and the target position is obtained;

[0030] According to 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 positioning device and the target position, the acoustic impedance value of the detected stratum is obtained;

[0031] According to the acoustic impedance value of the detected stratum, the lithological feature of the detected stratum is identified.

[0032] In an optional embodiment of the present disclosure, the distance between the ultrasonic detection positioning device and the target position is obtained according to the time difference between the emitted ultrasonic signal and the received echo signal, comprising:

[0033] transforming the echo signal from a time domain signal to a frequency domain signal;

[0034] obtaining the frequency variation coefficient between the echo signal and the emitted ultrasonic signal according to the frequency of the echo signal and the frequency of the emitted ultrasonic signal;

[0035] quantifying the lithological characteristics of the detected stratum according to the acoustic impedance of the detected stratum and the frequency variation coefficient between the frequency of the echo signal and the frequency of the emitted ultrasonic signal.

[0036] The present disclosure provides an old well open hole section tracking and identifying device for implementing the old well open hole section tracking and identifying method described above, the old well open hole section tracking and identifying device comprising:

[0037] The ultrasonic detection positioning device is lowered into the rescue well, and the ultrasonic detection positioning device is used for ultrasonic detection on the outer periphery of the rescue well and obtains an ultrasonic detection result; wherein the ultrasonic detection result comprises the position of the sediment in the old well and / or the position of the original stratum and / or the boundary position between the sediment in the old well and the original stratum;

[0038] The data acquisition device is located on the ground, and the signal receiving end of the data acquisition device is electrically connected to the signal output end of the ultrasonic detection positioning device through a communication cable, and the data acquisition device is used for receiving the ultrasonic detection result.

[0039] In an optional embodiment of the present disclosure, the old well open hole section tracking and identifying device further comprises a magnetic guide device, the magnetic guide device is electrically connected to the data acquisition device through a communication cable, and the magnetic guide device is used for detecting the position of the old well casing above the open hole section of the old well and guiding the rescue well to drill into the open hole section of the old well.

[0040] In an optional embodiment of the present disclosure, the ultrasonic detection positioning device comprises sequentially connected communication short sections, directional short sections, steering drive short sections and ultrasonic probes, the communication device is arranged in the communication short section, the signal output end of the communication device is electrically connected to the signal receiving end of the data acquisition device through a communication cable, the gyroscope is arranged in the directional short section, the signal output end of the gyroscope is electrically connected to the signal receiving end of the data acquisition device through a communication cable, the drive motor is arranged in the steering drive short section, and the output shaft of the drive motor is connected to the ultrasonic probe to drive the ultrasonic probe to rotate along the circumference of the rescue well.

[0041] In an optional embodiment of the present disclosure, a storage nipple is connected between the communication nipple and the directional nipple, and a data storage is arranged in the storage nipple, which is used to store the azimuth data detected by the gyroscope, the ultrasonic signal data emitted by the ultrasonic probe, and the received echo signal data.

[0042] From the above, the present disclosure has the following characteristics and advantages:

[0043] The rescue well is drilled to communicate with the open hole section of the old well, a reference position is determined in the old well, the reference position is taken as the starting position for tracking and identifying the open hole section of the old well, the ultrasonic detection and positioning device is lowered into the rescue well to the starting position where the ultrasonic detection and positioning device enters the old well, while the rescue well is drilled from the starting position, the ultrasonic detection and positioning device performs ultrasonic detection along the circumference of the rescue well, since the sediment in the old well and the original stratum have different acoustic impedances, the positions of the sediment in the old well, the positions of the original stratum, and the interface positions between the sediment in the old well and the original stratum can be identified according to the ultrasonic detection results, and the relative positions between the rescue well and the open hole section of the old well are obtained, according to the different relative positions between the rescue well and the open hole section of the old well, the drilling direction of the rescue well can be adjusted so that the drilling direction of the rescue well is directed towards the old well or consistent with the extension direction of the old well, so as to guide the drill bit to continuously track the drilling of the open hole section of the old well, until the rescue well drills to the target stratum, and effective plugging operation of the open hole section of the old well is performed, thereby ensuring the sealing integrity of the gas storage. BRIEF DESCRIPTION OF DRAWINGS

[0044] The following drawings are only intended to schematically illustrate and explain the present disclosure, and do not limit the scope of the present disclosure. Among them:

[0045] Figure 1 is a flowchart of the method for tracking and identifying the open hole section of the old well according to the present disclosure.

[0046] Figure 2 is a flowchart of the method for tracking and identifying the open hole section of the old well according to the present disclosure.

[0047] Figure 3 is a flowchart of the method for tracking and identifying the open hole section of the old well according to the present disclosure.

[0048] Figure 4 is a structural schematic diagram of guiding the drilling of the rescue well to communicate with the old well in the method for tracking and identifying the open hole section of the old well according to the present disclosure.

[0049] Figure 5 is a schematic diagram of the positional relationship between the rescue well and the open hole section of the old well according to the present disclosure.

[0050] Figure 6 is a schematic diagram of the positional relationship between the rescue well and the open hole section of the old well according to the present disclosure.

[0051] Figure 7 is a schematic view of the positional relationship between the rescue well and the open hole section of the old well in the method for tracking and identifying the open hole section of the old well according to the present disclosure.

[0052] Figure 8 is a schematic view of the structure of the ultrasonic detection positioning device in the device for tracking and identifying the open hole section of the old well according to the present disclosure.

[0053] Figure 9 is a waveform diagram of the echo signals of the original formation and the echo signals of the deposits in the old well collected by the ultrasonic detection positioning device in the device for tracking and identifying the open hole section of the old well according to the present disclosure.

[0054] The reference numerals in the present disclosure are as follows: 1, data acquisition device; 2, communication cable; 3, open hole section of old well; 4, rescue well; 5, original formation; 6, old well casing; 7, fish; 8, ultrasonic detection positioning device; 801, communication nipple; 802, storage nipple; 803, directional nipple; 804, connecting nipple; 805, steering drive nipple; 806, ultrasonic probe; 9, magnetic guidance device; 10, reference position. DETAILED DESCRIPTION

[0055] In order to have a clearer understanding of the technical features, objectives and effects of the present disclosure, the specific embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0056] Embodiment One

[0057] As shown in Figures 1 to 9, the present disclosure provides a method for tracking and identifying the open hole section of an old well, which uses a rescue well 4 to reopen the old well filled with deposits, and the method for tracking and identifying the open hole section of the old well comprises the following steps:

[0058] Step S1: drilling the rescue well 4 to communicate with the open hole section 3 of the old well;

[0059] Further, as shown in Figures 4 to 7, the starting drilling position of the rescue well 4 is different from the position of the old well, and before the rescue well 4 is drilled to communicate with the open hole section 3 of the old well, the magnetic guidance device 9 can be used to guide the rescue well 4 to drill to communicate 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 in the old well, the magnetic guidance device 9 can be used to determine the direction of the old well by capturing the magnetic signals of the old well casing 6, thereby realizing the drilling of the rescue well 4. The magnetic guidance device 9 can use, but is not limited to, the existing MGD magnetic guidance drilling equipment for precise navigation drilling, and other devices capable of detecting magnetic signals can also be used, and the specific device is not limited here.

[0060] In the above process, the magnetic guiding device 9 detects the position of the old well casing 6 and the fish 7 in the old well while the rescue well 4 is being drilled, and guides the rescue well 4 to drill to the bottom of the fish 7 in the old well or the position of the casing shoe located at the upper part of the open hole section 3 of the old well, so that the rescue well 4 communicates with the open hole section 3 of the old well.

[0061] Step S2: determining a reference position 10 in the old well, and taking the reference position 10 as the starting position for tracking and identifying the open hole section 3 of the old well;

[0062] The starting position can be the bottom of the fish 7 in the old well or the position of the casing shoe located at the upper part of the open hole section 3 of the old well (i.e. below the old well casing 6), which is the starting position of the open hole section 3 of the old well, so that the above-mentioned position can be taken as the starting position for the next step of ultrasonic detection and tracking identification, so as to ensure the complete tracking and identification of the open hole section 3 of the old well as a whole.

[0063] Step S3: lowering the ultrasonic detection and positioning device 8 into the old well to the starting position;

[0064] Step S4: from the starting position, the ultrasonic detection and positioning device 8 performs ultrasonic detection along the circumference of the rescue well 4, and obtains an ultrasonic detection result; the ultrasonic detection result includes the position of the deposits in the old well, and / or the position of the original formation 5, and / or the boundary position between the deposits in the old well and the original formation 5;

[0065] Step S5: adjusting the drilling direction of the rescue well 4 according to the ultrasonic detection result, so that the drilling direction of the rescue well 4 is towards the old well or consistent with the extension direction of the old well, so that the rescue well 4 can be restored to the drilling direction consistent with the extension direction of the open hole section 3 of the old well;

[0066] Step S6: drilling the bottom or the well section close to the bottom of the rescue well 4 to coincide with the open hole section 3 of the old well and be located in the target formation;

[0067] Step S7: performing plugging operation on the open hole section 3 of the old well through the rescue well 4.

[0068] In the present disclosure, the drilling relief well 4 is drilled to the open hole section 3 of the old well, the reference position 10 is determined in the old well, the reference position 10 is taken as the starting position for tracking and identifying the open hole section 3 of the old well, the ultrasonic detection positioning device 8 is lowered into the relief well 4 to the starting position where the ultrasonic detection positioning device 8 enters into the old well, and the ultrasonic detection positioning device 8 performs ultrasonic detection along the circumference of the relief well 4 while the relief well 4 is drilled from the starting position. The location of the deposits in the old well can be the spatial distribution range (for example, the geometric boundary in a three-dimensional coordinate system) of the deposit-filled area in the open hole section 3 of the old well, and the location of the original formation can be the spatial distribution of the undisturbed rock formation that has not been disturbed by the open hole section 3 of the old well. The interface location can be the contact interface between the original well wall of the open hole section of the old well and the undisturbed formation. Since the deposits in the old well and the original formation 5 have different acoustic impedances, the location of the deposits in the old well, the location of the original formation 5, and the interface location between the deposits in the old well and the original formation 5 can be identified according to the ultrasonic detection results, and the relative position between the relief well 4 and the open hole section 3 of the old well is obtained. According to the different relative positions between the relief well 4 and the open hole section 3 of the old well, the drilling direction of the relief well 4 can be adjusted so that the drilling direction of the relief well 4 is directed 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, thereby achieving the purpose of guiding the drill bit to continuously track the drilling of the open hole section 3 of the old well, until the relief well 4 reaches the target formation and the effective plugging operation of the open hole section 3 of the old well is performed, thereby ensuring the sealing integrity of the gas storage.

[0069] During the ultrasonic detection, the location of the deposits in the old well, the location of the original formation 5, and the interface location between the deposits in the old well and the original formation 5 can be identified according to the ultrasonic detection results. According to different ultrasonic detection results, the location of the original formation 5 and the open hole section 3 of the old well and the interface location therebetween can be accurately identified and distinguished. The interface location between the deposits in the old well and the original formation 5 can be the location of the original well wall of the open hole section of the old well. It should be understood that the open hole section 3 of the old well contains loose substances (such as rock cuttings, silt, etc.) due to well wall collapse, drilling fluid residue, or long-term accumulation, which have low acoustic impedance and uneven structure. The original formation 5 is a natural rock formation that has not been drilled or disturbed by the old well, maintains the original dense structure and acoustic properties, and has high acoustic impedance. By detecting the interface location through ultrasonic detection, the actual trend of the open hole section of the old well can be inferred. Specifically, when the relative position relationship between the relief well 4 and the open hole section 3 of the old well is completely coincident, the relief well 4 continues to drill along the extension direction of the old well, and the drilling direction of the relief well 4 does not need to be adjusted. When the relative position between the relief well 4 and the open hole section 3 of the old well is partially coincident or there is no coincident part, the drilling direction of the relief well 4 needs to be adjusted towards the open hole section 3 of the old well, so as to achieve the purpose of guiding the drill bit to continuously track the drilling of the open hole section 3 of the old well and ensure the effective plugging operation of the open hole section 3 of the old well.

[0070] In one optional embodiment of the present disclosure, as shown in FIG. 5, if the ultrasonic detection result is that the deposits in the old well and the interface between the deposits in the old well and the original stratum 5 are detected along the circumference of the relief well 4, the relief well 4 completely coincides with the open hole section 3 of the old well (i.e. the relief well 4 completely falls in the open hole section 3 of the old well), and the relief well 4 continues to drill along the extension direction of the open hole section 3 of the old well. In this working condition, the ultrasonic detection result is that the rocks identified along the well circumference are all the deposits in the old well, and there is a clear interface between the original stratum 5 and the open hole section 3 of the old well, so the relief well 4 can continue to drill along the established trajectory without adjusting the drilling direction of the relief well 4.

[0071] In another optional embodiment of the present disclosure, as shown in FIG. 6, if the ultrasonic detection result is that the deposits in the old well are detected on one side along the circumference of the relief well 4, the original stratum 5 is detected on the opposite side, and only the interface between the deposits in the old well and the original stratum 5 is detected on one side, the relief well 4 partially coincides with the open hole section 3 of the old well (i.e. a part of the relief well 4 falls in the open hole section 3 of the old well), and the relief well 4 is adjusted to deflect to the side where the deposits in the old well are located. In this working condition, the ultrasonic detection result is that the rocks identified on one side along the well circumference are the deposits in the old well, and the rocks identified on the opposite side 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, so the subsequent drilling direction of the relief well 4 needs to be adjusted according to the identified deposits in the old well, original stratum 5 and interface between the original stratum 5 and the open hole section 3 of the old well, and the drilling trajectory of the relief well 4 is corrected so that the relief well 4 drills towards the inside of the open hole section 3 of the old well.

[0072] In still another optional embodiment of the present disclosure, as shown in FIG. 7, if the ultrasonic detection result is that the original stratum 5 is detected along the circumference of the relief well 4, and only the interface between the deposits in the old well and the original stratum 5 is detected on one side, the relief well 4 partially deviates from the open hole section 3 of the old well and does not coincide with the open hole section 3 of the old well, and the relief well 4 is adjusted to deflect to the side where the interface between the deposits in the old well and the original stratum 5 is located. In this working condition, the ultrasonic detection result is that the rocks identified along the well circumference are all 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, so the subsequent drilling direction of the relief well 4 needs to be adjusted according to the identified interface between the original stratum 5 and the open hole section 3 of the old well, and the drilling trajectory of the relief well 4 is corrected so that the relief well 4 drills towards the open hole section 3 of the old well.

[0073] Since the medium for conducting the ultrasonic signal between the deposit in the open hole section 3 of the old well and the original stratum 5 is different, the reflection characteristics of the same ultrasonic signal are different, as shown in FIG. 9, the amplitude of the echo signal of the original stratum 5 is obviously higher than that of the deposit in the open hole section 3 of the old well. In the present disclosure, the ultrasonic detection positioning is also based on the characteristic phenomenon to accurately identify and distinguish the original stratum 5, the open hole section 3 of the old well and the interface therebetween.

[0074] In the implementation process of the present disclosure, the echo signal of the ultrasonic wave is affected by many factors due to the complex working conditions in the rescue well 4. In order to more accurately identify and judge the characteristic data of the echo signal, thereby identifying the lithology of the target stratum, in an optional embodiment of the present disclosure, an echo signal processing model can be established to improve the accuracy of identifying the echo signal.

[0075] In the present embodiment, as shown in FIG. 2, the ultrasonic detection result (i.e. step S5) is obtained, including:

[0076] Step S501: establishing an echo signal processing model according to the echo signal of the emitted ultrasonic wave;

[0077] Step S502: identifying the characteristic data of the actual echo signal according to the echo signal processing model;

[0078] Step S503: identifying the lithology characteristics of the detected stratum according to the characteristic data to determine whether the detected stratum is the position of the deposit in the old well, the position of the original stratum or the interface position between the deposit in the old well and the original stratum.

[0079] Further, the echo signal processing model in step S501 includes:

[0080] Step S5011: obtaining the distance between the ultrasonic detection positioning device and the target position according to the time difference between the emitted ultrasonic signal and the received echo signal;

[0081] Wherein, the distance between the ultrasonic detection positioning device and the target position satisfies:

[0082] Wherein, L is the distance between the ultrasonic detection positioning device and the target position; Δt is the time difference between the emission of the ultrasonic signal and the reception of the echo signal; v is the propagation speed of the ultrasonic wave.

[0083] Step S5012: obtaining the acoustic impedance value of the detected stratum according to 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 positioning device and the target position;

[0084] The ultrasonic signal is emitted from the ultrasonic detection positioning device 8, propagates through the distance L between the ultrasonic detection positioning device and the target position to the detection target (the original stratum 5 or the open hole section 3 of the old well), and is reflected by the detection target (the original stratum 5 or the open hole section 3 of the old well) to return a part of the signal (i.e., the echo signal) to the ultrasonic detection positioning device 8. During the emission of the ultrasonic signal and the reception of the echo signal, the following conditions are met:

[0085] wherein P S is the sound pressure amplitude of the ultrasonic signal emitted by the ultrasonic detection positioning device at the initial time, P e is the sound pressure amplitude of the echo signal received by the ultrasonic detection positioning device at the end time, a is the signal attenuation coefficient of the ultrasonic signal changing with the propagation distance in the medium, Z r is the acoustic impedance of the detection target (the sediment in the original stratum or the open hole section of the old well), and Z w is the acoustic impedance of the working fluid in the well.

[0086] Further, the above sound pressure amplitude can be calculated using the sensitivity of the ultrasonic transducer, and the calculation is as follows:

[0087] wherein VV S is the excitation voltage of the ultrasonic transducer when the ultrasonic signal is emitted by the ultrasonic detection positioning device, VV e is the voltage excited by the echo signal when the echo signal is received by the ultrasonic detection positioning device, 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).

[0088] The acoustic impedance of the detection target can be calculated by simultaneously solving the above formulas (1), (2), (3), and (4).

[0089] Step S5013: According to the acoustic impedance value of the detected stratum (i.e., the target position), the lithological characteristics of the detected stratum are identified.

[0090] In an optional embodiment of the present disclosure, during the acquisition of the acoustic impedance value of the detected stratum, since impurities (such as rock debris, bubbles, etc.) exist in the working fluid in the well, the temperature and the density of the working fluid in the well also change, and therefore, the signal attenuation coefficient a needs to be corrected: a c = a x γ (m, T, p...) (5)

[0091] wherein a c is the corrected signal attenuation coefficient, m is the component of the working fluid in the well, T is the temperature in the well, and p is the density of the working fluid in the well.

[0092] In an optional embodiment of the present disclosure, step S5011 comprises:

[0093] Step S50111: The echo signal is transformed and processed to transform the echo signal from a time domain signal to a frequency domain signal;

[0094] Wherein, the echo signal is transformed from a time domain signal to a frequency domain signal as follows:

[0095] F(w) = ∫f(t)e (-jwt) dt (6)

[0096] Wherein, F(w) represents a complex function in the frequency domain, f(t) represents a time domain sequence function of the ultrasonic signal, w represents the frequency, e (-jwt) represents a complex exponential function.

[0097] Step S50112: According to the frequency of the echo signal and the frequency of the emitted ultrasonic signal, the frequency change coefficient between the two is obtained;

[0098] Specifically, the main frequency fmain can be calculated from the above formula (6), and the change coefficient between the main frequency of the echo signal and the frequency of the emitted ultrasonic signal is constructed:

[0099] τ = τ(|f main -F S |) (7)

[0100] Wherein, F S is the frequency of the ultrasonic signal emitted by the ultrasonic detection and positioning device at the initial moment, and τ is the change coefficient between the main frequency of the echo signal and the frequency of the emitted ultrasonic signal.

[0101] Step S50113: According to the acoustic impedance of the detected stratum and the frequency change coefficient between the frequency of the echo signal and the frequency of the emitted ultrasonic signal, the lithology characteristics of the detected stratum are quantified: θ = θ(Z r , τ).

[0102] The characteristics and advantages of the old well open hole section tracking and identification method of the present disclosure are:

[0103] The old well open hole section tracking and identifying method can identify at least the position of the deposit in the old well, the position of the original stratum 5 and the boundary position between the deposit in the old well and the original stratum 5 according to the difference between the deposit in the old well and the lithology of the original stratum 5 by using the ultrasonic detection method, so as to obtain the relative position between 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 according to the different relative positions of the rescue well 4 and the open hole section 3 of the old well, so as to guide 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 the effective plugging operation of the open hole section 3 of the old well is performed, thereby ensuring the sealing integrity of the gas storage.

[0104] Embodiment two

[0105] As shown in FIGS. 4 to 8, the present disclosure provides an old well open hole section tracking and identifying device for implementing the above-mentioned old well open hole section tracking and identifying method. The old well open hole section tracking and identifying device comprises 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 is used for ultrasonic detection of the outer periphery of the rescue well 4 and obtains an ultrasonic detection result. The ultrasonic detection result includes the identified position of the deposit in the old well, and / or the position of the original stratum 5, and / or the boundary position between the deposit in 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 through a communication cable 2, and the data acquisition device 1 is used for receiving the ultrasonic detection result. The ultrasonic signal emitted by the ultrasonic detection and positioning device 8 and the received echo signal can be transmitted to the data acquisition device 1 for data reception and storage, so as to ensure accurate tracking and identification of the open hole section 3 of the old well.

[0106] The communication cable 2 can be, but is not limited to, a cable.

[0107] In an optional embodiment of the present disclosure, as shown in FIG. 4, the old well open hole section tracking and identifying device further comprises a magnetic guiding device 9 electrically connected to the data acquisition device 1 through the communication cable 2. The magnetic guiding device 9 is used for detecting the position of the old well casing 6 located above the open hole section of the old well and guiding the rescue well to drill into communication with the open hole section of the old well. Since there is the old well casing 6 above the open hole section 3 of the old well in the old well, the magnetic guiding device 9 can be used to capture the magnetic signal of the old well casing 6 to determine the direction of the old well before the rescue well 4 is drilled into communication with the open hole section 3 of the old well, and the data is transmitted to the data acquisition device 1, so as to realize the drilling of the rescue well 4. The magnetic guiding device 9 can use, but is not limited to, the existing MGD magnetic guiding drilling equipment for precise navigation drilling.

[0108] In an optional embodiment of the present disclosure, as shown in FIG. 8, the ultrasonic detection positioning device 8 comprises sequentially connected communication nipple 801, orientation nipple 803, steering drive nipple 805 and ultrasonic probe 806, wherein the communication nipple 801 is provided with a communication device, the signal output end of the communication device is electrically connected with the signal receiving end of the data acquisition device 1 through the communication cable 2, the orientation nipple 803 is provided with a gyroscope, the signal output end of the gyroscope is electrically connected with the signal receiving end of the data acquisition device 1 through the communication cable 2, the orientation of the ultrasonic probe 806 can be detected in real time through the gyroscope, so as to ensure accurate monitoring of the drilling direction and adjustment direction of the rescue well 4. The steering drive nipple 805 is provided with a driving motor, the output shaft of the driving motor is connected with the ultrasonic probe 806, so as to drive the ultrasonic probe 806 to rotate along the circumference of the rescue well 4, thereby realizing detection of each orientation along the circumference of the rescue well 4.

[0109] Further, as shown in FIG. 8, the communication nipple 801 and the orientation nipple 803 are connected with a storage nipple 802, the storage nipple 802 is provided with a data storage, the signal receiving end of the data storage is electrically connected with the signal output end of the gyroscope and the signal output end of the ultrasonic probe 806, and the data storage 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.

[0110] Further, as shown in FIG. 8, the orientation nipple 803 and the steering drive nipple 805 are provided with a connecting nipple 804, the two ends of the connecting nipple 804 are fixedly connected or rotatably connected with the orientation nipple 803 and the steering drive nipple 805, so as to realize connection of the orientation nipple 803 and the steering drive nipple 805.

[0111] The old well open hole section tracking and identifying device of the present disclosure has the same characteristics and advantages as the old well open hole section tracking and identifying method described above, and will not be described here.

[0112] The above merely illustrates the specific implementation of the present disclosure, and is not used to limit the scope of the present disclosure. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present disclosure shall fall within the scope of protection of the present disclosure.

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-eye 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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