Continuous detection type sleeve external optical fiber positioning device and use method

Abstract

The invention discloses a continuous detection type sleeve outer optical fiber positioning device and a use method, and the method comprises the steps: arranging an armored optical fiber on a metal sleeve, and wrapping the metal sleeve with a cement sheath; the underground detector is externally connected with a power device, and the underground detector is driven by the power device to move in the metal sleeve; the underground detector is electrically connected with the computer, detected data are sent to the computer, underground optical fiber detection can be effectively carried out, and the detection efficiency is improved; meanwhile, sectorial detection is carried out by utilizing an annular receiving array of a receiving sensor, directional detection and region division are realized, stable and correct information is provided for accurate inversion explanation of a medium outside a downhole casing, and detected media such as optical fibers outside the casing can be accurately identified and positioned.

Description

Technical Field

[0001] The present invention belongs to the technical field of target detection, and relates to a continuous detection type optical fiber positioning device outside a casing and a using method thereof. Background Art

[0002] At present, in order to improve the efficiency of downhole information management in oil fields, optical fibers are permanently arranged on the outer wall of the casing during the completion process of oil and gas wells to realize the monitoring of downhole dynamic conditions, so as to analyze downhole information and adjust the development plan. After the completion of oil and gas wells, perforation operations are required. When optical fibers are deployed outside the casing, if perforation is carried out according to the conventional spiral uniform hole arrangement method, it is very likely to cause damage or even breakage of the optical fibers outside the casing. Therefore, how to accurately locate the specific orientation of the optical fibers outside the casing before perforation is a technical problem that must be solved.

[0003] At present, downhole optical fiber detection and positioning mainly rely on the DC-MOT (DC-Magnetic Orientation Tool, a DC magnetic orientation tool) instrument of Hunting Company in the United States. DC-MOT is a downhole single-point test tool that uses the method of motor-assisted probe measurement to perform circumferential detection on a certain measurement point. During the detection process, the motor drives the probe to rotate circumferentially. When the motor rotates 360 degrees, a set of data can be obtained. Subsequently, by comparing the detection data on this circumference, the rotation position with the highest measured metal mass is found and determined as the position of the optical fiber. The main disadvantage of this method is that it cannot perform continuous measurement. It is necessary to find the position of the measured clamp in advance, place the instrument statically at this position, rotate the probe 360 degrees, and then compare the detection data on this circumference to find the position of the optical fiber, resulting in low efficiency. The instrument mainly has the following problems: it is necessary to know the clamp position in advance and then perform positioning manually; the detection process needs to be stationary at a certain point for measurement, the measurement is not continuous, and the speed is slow; the DC-MOT instrument can only measure the collar position, and there is a measurement point every ten meters in depth, resulting in low longitudinal resolution. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems in the prior art that when performing downhole optical fiber detection and positioning, it is necessary to know the clamp position in advance and then perform positioning manually; the detection process needs to be stationary at a certain point for measurement, the measurement is not continuous, and the speed is slow; the DC-MOT instrument can only measure the collar position, and there is a measurement point every ten meters in depth, resulting in low longitudinal resolution, and to provide a continuous detection type optical fiber positioning device outside a casing and a using method thereof.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A continuous detection type optical fiber positioning device outside a casing includes: armored optical fiber, metal casing, downhole detector, power device, and computer;

[0007] The armored optical fiber is laid on the metal sleeve, and the metal sleeve is wrapped by a cement ring; the downhole detector is externally connected to a power device, and the downhole detector moves inside the metal sleeve driven by the power device; the downhole detector is electrically connected to a computer, and the detected data is sent to the computer.

[0008] A further improvement of the present invention lies in:

[0009] Furthermore, an optical fiber clamp and a sleeve clamp are provided on the metal sleeve; the sleeve clamp is arranged inside the optical fiber clamp; the optical fiber clamp fixes the armored optical fiber; the metal sleeve has several sections; the sleeve clamp is arranged at the connection of adjacent metal sleeves to fix the adjacent metal sleeves.

[0010] Furthermore, the downhole detector includes an upper centralizer, a lower centralizer, a first sleeve, a transmitting coil, a second sleeve, a sensor array and a main control chip; the upper centralizer and the lower centralizer are respectively arranged at both ends of the first sleeve; the transmitting coil is arranged inside the second sleeve; the second sleeve is arranged inside the first sleeve; the sensor array is evenly arranged around the transmitting coil, and the sensor array is embedded inside the second sleeve; the sensor array and the transmitting coil are electrically connected to the main control chip, and the main control chip is electrically connected to the computer.

[0011] Furthermore, the sensor array is composed of 32 sensors evenly arranged around the transmitting coil.

[0012] Furthermore, the structure of the lower centralizer is the same as that of the upper centralizer.

[0013] Furthermore, the upper centralizer is externally connected to a power device, and the power device drives the downhole detector to move inside the metal sleeve through the upper centralizer.

[0014] A usage method of a continuous detection type optical fiber positioning device outside the casing includes: placing the metal sleeve and the armored optical fiber inside a wellbore filled with cement slurry; slowly raising the downhole detector arranged inside the metal sleeve along the inner wall of the metal sleeve through the power device; the transmitting coil and the sensor array continuously measure the change of the magnetic field intensity within a certain range around the metal sleeve along the inner wall of the metal sleeve; the sensor array sends the measured data to the main control chip, and the main control chip processes the data and sends it to the computer; after measuring the magnetic field distribution of the entire well section, the downhole magnetic detector is lifted out of the wellbore opening.

[0015] Furthermore, the transmitting coil and the sensor array continuously measure the change in the magnetic field intensity within a certain range around the metal casing along the inner wall of the metal casing. Specifically: A periodic broadband pulsed current signal is applied to the transmitting coil, which generates a rapidly decaying pulsed magnetic field, i.e., the primary field, in the surrounding medium; during the intermittent period of the pulsed current, the rapid change in the current signal will induce an induced current around the casing, known as eddy current or secondary current; due to the thermal loss of the conductive medium, the induced current will rapidly decay over time and generate an eddy current magnetic field around it, i.e., the secondary field received by the sensor array.

[0016] Furthermore, the main control chip processes the data, specifically: determining the correspondence between the magnetic field intensity and the casing clamp, fiber optic clamp, and armored optical fiber; the correspondence between the sensor label and the circumferential orientation of the pipeline; inferring the position of the armored optical fiber in the circumferential direction based on the change trend of the magnetic field intensity corresponding to the fiber optic clamp and the casing clamp; analyzing and verifying the detection and identification performance of the downhole magnetic detector for the armored optical fiber based on the acquired array data; and respectively conducting a comparative analysis of the detection effects on the metal casing, casing clamp, fiber optic clamp, and armored optical fiber.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] In the present invention, the armored optical fiber is laid on the metal casing, and the metal casing is wrapped by a cement ring; the downhole detector is externally connected to a power device, and the downhole detector moves inside the metal casing driven by the power device; the downhole detector is electrically connected to a computer and sends the detected data to the computer. The present invention can effectively conduct downhole optical fiber detection and improve the detection efficiency.

[0019] Furthermore, the present invention uses the annular receiving array of the receiving sensor for sector detection, realizes directional detection and area division, provides stable and error-free information for the accurate inversion and interpretation of the medium outside the downhole casing, and can accurately identify and locate the detected media such as the optical fiber outside the casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 (a) is a schematic structural diagram of the continuous detection type optical fiber positioning device outside the casing of the present invention;

[0022] Figure 1 (b) is an enlarged schematic diagram of the continuous detection type casing instrument;

[0023] Figure 2 It is a schematic structural diagram of a transmitting system and a receiving system;

[0024] Figure 3 It is a schematic flow diagram of the usage method of a continuous detection type optical fiber positioning device outside the casing;

[0025] Figure 4 It is a schematic diagram of the optical fiber distribution outside the casing;

[0026] Figure 5 It is a schematic diagram of the instrument movement direction and the corresponding time.

[0027] Among them, 1 - sensor array; 2 - transmitting coil; 3 - metal casing; 4 - second casing; 5 - upper centralizer; 6 - lower centralizer; 7 - optical fiber clamp; 8 - casing clamp; 9 - downhole detector; 10 - first casing. Specific embodiments

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0031] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is usually placed during use, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention. In addition, terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0032] In addition, when the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and it does not mean that the structure must be completely horizontal, but it can be slightly inclined.

[0033] In the description of the embodiments of the present invention, it should also be noted that unless otherwise clearly specified and limited, when terms such as "set", "installed", "connected", and "connected" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0034] The present invention will be further described in detail below with reference to the accompanying drawings:

[0035] See Figure 1 (a), Figure 1 (b) and Figure 2 , the present invention discloses a continuous detection type optical fiber positioning device outside the casing, including: armored optical fiber, metal casing 3, downhole detector 9, power device and computer; the armored optical fiber is arranged on the metal casing 3, and the metal casing 3 is wrapped by a cement ring; the downhole detector 9 is externally connected to the power device, and the downhole detector 9 moves inside the metal casing 3 driven by the power device; the downhole detector 9 is electrically connected to the computer and sends the detected data to the computer.

[0036] Optical fiber clamps 7 and casing clamps 8 are arranged on the metal casing 3; the casing clamp 8 is arranged inside the optical fiber clamp 7; the optical fiber clamp 7 fixes the armored optical fiber; the metal casing 3 has several sections; the casing clamp 8 is arranged at the connection of adjacent metal casings 3 to fix the adjacent metal casings 3.

[0037] The downhole detector 9 includes an upper centralizer 5, a lower centralizer 6, a first casing 10, a transmitting coil 2, a second casing 4, a sensor array 1 and a main control chip; the upper centralizer 5 and the lower centralizer 6 are respectively arranged at both ends of the first casing 10; the transmitting coil 2 is arranged inside the second casing 4; the second casing 4 is arranged inside the first casing 10; the sensor array 1 is uniformly arranged around the transmitting coil 2, and the sensor array 1 is embedded inside the second casing 4; the sensor array 1 and the transmitting coil 2 are electrically connected to the main control chip, and the main control chip is electrically connected to the computer.

[0038] The sensor array 1 has 32 sensors evenly arranged around the transmitting coil 2. The structure of the lower centralizer 6 is the same as that of the upper centralizer 5. The upper centralizer 5 is externally connected to a power device, and the power device drives the downhole detector 9 to move inside the metal casing 3 through the upper centralizer 5.

[0039] In Figure 1 In the left figure, the cement sheath outside the casing is wrapped outside the casing, and the enlarged view of the instrument inside the casing is shown in the right figure, which is divided into an upper centralizer, a receiving sensor array, and a lower centralizer. Based on the GMR ring array, 32 GMR receiving sensors are evenly distributed around the center of the transient electromagnetic transmitting probe. The annular GMR array receives and converts the secondary field signals on the same horizontal plane. In this way, the receiving sensors closer to the optical fiber will produce a stronger response.

[0040] A method for using a continuous detection type optical fiber positioning device outside the casing includes: placing the metal casing 3 and the armored optical fiber inside a well filled with cement slurry; slowly raising the downhole detector 10 arranged inside the metal casing 3 along the inner wall of the metal casing 3 through a power device; the transmitting coil 2 and the sensor array 1 continuously measure the change in the magnetic field intensity within a certain range around the metal casing 3 along the inner wall of the metal casing 3; the sensor array 1 sends the measured data to the main control chip, and the main control chip processes the data and sends it to a computer; after measuring the magnetic field distribution of the entire well section, the downhole magnetic detector 10 is lifted out of the wellhead.

[0041] The transmitting coil 2 and the sensor array 1 continuously measure the change in the magnetic field intensity within a certain range around the metal casing 3 along the inner wall of the metal casing 3. Specifically: a periodic broadband pulse current signal is applied to the transmitting coil 2, and this signal will generate a rapidly decaying pulse magnetic field in the surrounding medium, that is, the primary field; during the intermittent period of the pulse current, the rapid change in the current signal will induce an electric current around the casing, which is called eddy current or secondary current; due to the thermal loss of the conductive medium, the induced current will rapidly decay with time and generate an eddy current magnetic field around it, that is, the secondary field received by the sensor array 1. The main control chip processes the data. Specifically: determining the correspondence between the magnetic field intensity and the casing clamp 8, the optical fiber clamp 7, and the armored optical fiber; the correspondence between the sensor label and the circumferential azimuth of the pipeline; inferring the position of the armored optical fiber in the circumferential direction based on the change trend of the magnetic field intensity corresponding to the optical fiber clamp 7 and the casing clamp 8; analyzing and verifying the detection and identification performance of the downhole magnetic detector 10 for the armored optical fiber based on the acquired array data; respectively comparing and analyzing the detection effects of the metal casing 3, the casing clamp 8, the optical fiber clamp 7, and the armored optical fiber.

[0042] Example: See Figure 3 、 Figure 4 and Figure 5, this instrument uses the annular receiving array of the receiving sensor for sector detection to achieve directional detection and area division. At each depth, the direction of the optical fiber relative to these 32 sensors can be measured once. As the instrument moves, the position of the optical fiber can be continuously obtained, thereby realizing the automatic detection and continuous measurement of the position of the optical fiber outside the downhole casing. This device mainly consists of two parts: a transmitting system and a receiving system. Its working process can be divided into two stages. First, a periodic broadband pulsed current signal is applied to the transmitting coil. This signal will generate a rapidly decaying pulsed magnetic field, i.e., the primary field, in the surrounding medium. At this time, no signal is received. During the intermittent period of the pulsed current, the sudden change in the current signal will induce an induced current, called eddy current or secondary current, around the casing. Due to the thermal loss of the conductive medium, this induced current will rapidly decay with time and generate an eddy current magnetic field around it, i.e., the secondary field that can be received by the sensor array. Figure 4 , at each depth, the position of the primary optical fiber relative to 32 sensors can be measured. As the instrument continuously moves upward, the position of the optical fiber outside the casing can be continuously measured.

[0043] Step 1, arrange the annular array receiving probes on the probe head of the in-pipe detector according to the preset spatial positions. First, place the sensors in the corresponding grooves of the bracket, and then press the sensors tightly so that the sensor bases are closely attached to the surface of the grooves. Use melting glue to seal the four sides of the sensor bases for fixation. Complete the loading of the sensors for the four groups of probes in a similar method.

[0044] The transmitting coil uniformly excites the casing medium around the wellbore. Each receiving sensor mainly conducts casing damage detection towards a detection sector. At the same time, this type of receiving probe is only sensitive to a single magnetic field direction, which can reduce the magnetic field interference in other directions. Therefore, by analyzing the magnetic field response of only one of the receiving sensors, the magnetic field response curve around the wellbore can be obtained. By changing the parameter size of the probe, the detection range can be controlled. For the fluctuation of the sector magnetic field, this sensor will become more sensitive and can identify finer damage differences and the detection azimuth of their locations. The transient electromagnetic measurement model under this structure can retain the stable performance of the magnetic core winding probe in emitting the magnetic field, and without significantly changing the instrument structure and increasing the instrument power supply power consumption on the premise of greatly increasing the number of magnetic field detection sensors.

[0045] Step 2: The detector travels along the inner wall of the pipeline under the pulling of the single-core cable. The power device enables the detector to travel smoothly along the inner wall of the pipeline by providing appropriate pulling force, so as to achieve the detection task of the pipeline interior. During the traveling process, the detector can monitor and observe the inner wall of the pipeline in real time, obtain relevant data information through sensors, capture the magnetic field intensity information around the pipe wall in real time, and continuously measure the information around the pipe wall. Determine the one-to-one correspondence between the magnetic field intensity and the outer casing clamp and the optical fiber; the correspondence between the sensor label and the circumferential orientation of the pipeline. Infer the circumferential position of the optical fiber outside the casing based on the change trend of the magnetic field intensity corresponding to the fiber clamp collar. The detection and positioning system of the armored optical fiber outside the casing based on the transient electromagnetic array can achieve fast and high-precision acquisition of multi-sensor arrays. The designed working temperature is 175 °C, which can ensure normal operation under high-temperature and high-pressure gas wells.

[0046] Step 3: After obtaining the array data, appropriate processing is performed on the data of each array element. The detection effects of components such as the casing, collar, and optical fiber are respectively compared and analyzed, and the position offset of the optical fiber is verified. Currently, the speed of this instrument traveling along the inner wall of the pipeline is 300 m / h. It can achieve 240-point measurements within one meter, so as to achieve continuous measurement. Even if the missing measurement rate is 20%, it can still ensure 192-point measurements per meter. The collar of the downhole casing is 220 mm long, and each collar has 52 measurement points. The probability of detecting the collar in the actual well detection is 100%. The actual well detection results show that the detection and positioning system of the armored optical fiber outside the casing can effectively identify the optical fiber outside the casing and realize the positioning of the optical fiber through the circular array, which can provide an important basis for avoiding optical fiber perforation in oil and gas wells.

[0047] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A continuous detection type optical fiber positioning device outside the casing, characterized in that, Comprising: Armored optical fiber, metal casing (3), downhole detector (9), power unit, and computer; The armored optical fiber is disposed on the metal casing (3), and the metal casing (3) is wrapped by a cement sheath; the downhole detector (9) is externally connected to the power unit, and the downhole detector (9) moves inside the metal casing (3) driven by the power unit; the downhole detector (9) is electrically connected to the computer and transmits the detected data to the computer.

2. The continuous detection type optical fiber positioning device outside the casing according to claim 1, wherein The metal casing (3) is provided with an optical fiber clamp (7) and a casing clamp (8); the casing clamp (8) is disposed inside the optical fiber clamp (7); the optical fiber clamp (7) fixes the armored optical fiber; the metal casing (3) has several sections; the casing clamp (8) is disposed at the connection of adjacent metal casings (3) to fix the adjacent metal casings (3).

3. The continuous detection type optical fiber positioning device outside the casing according to claim 2, characterized in that The downhole detector (9) includes an upper centralizer (5), a lower centralizer (6), a first casing (10), a transmitting coil (2), a second casing (4), a sensor array (1), and a main control chip; the upper centralizer (5) and the lower centralizer (6) are respectively disposed at both ends of the first casing (10); the transmitting coil (2) is disposed inside the second casing (4); the second casing (4) is disposed inside the first casing (10); the sensor array (1) is uniformly disposed around the transmitting coil (2), and the sensor array (1) is embedded inside the second casing (4); the sensor array (1) and the transmitting coil (2) are electrically connected to the main control chip, and the main control chip is electrically connected to the computer.

4. The continuous detection type optical fiber positioning device outside the casing according to claim 3, characterized in that, The sensor array (1) is 32 sensors uniformly disposed around the transmitting coil (2).

5. The continuous detection type optical fiber positioning device outside the casing according to claim 4, wherein The structure of the lower centralizer (6) is the same as that of the upper centralizer (5).

6. The continuous detection type optical fiber positioning device outside the casing according to claim 5, wherein The upper centralizer (5) is externally connected to the power unit, and the power unit drives the downhole detector (9) to move inside the metal casing (3) through the upper centralizer (5).

7. A method for using the continuous detection type optical fiber positioning device outside the casing according to claim 6, characterized in that, Comprising: The metal casing (3) and the armored optical fiber are placed inside a wellbore filled with cement slurry; the downhole detector (10) disposed inside the metal casing (3) is slowly lifted along the inner wall of the metal casing (3) by the power unit; the transmitting coil (2) and the sensor array (1) continuously measure the change in the magnetic field strength within a certain range around the metal casing (3) along the inner wall of the metal casing (3); the sensor array (1) transmits the measured data to the main control chip, and the main control chip processes the data and transmits it to the computer; after measuring the magnetic field distribution of the entire well section, the downhole magnetic detector (10) is lifted out of the wellbore.

8. The method of using the continuous detection type optical fiber positioning device outside the casing according to claim 7, characterized in that, The transmitting coil (2) and the sensor array (1) continuously measure the change in the magnetic field intensity within a certain range around the inner wall of the metal casing (3). Specifically: A periodic broadband pulse current signal is applied to the transmitting coil (2), and this signal generates a rapidly decaying pulsed magnetic field in the surrounding medium, which is the primary field; during the intermittent period of the pulsed current, the rapid change in the current signal will induce an induced current around the casing, which is called eddy current or secondary current; due to the thermal loss of the conductive medium, the induced current will rapidly decay over time and generate an eddy current magnetic field around it, which is the secondary field received by the sensor array (1).

9. The method for using the continuous detection type optical fiber positioning device outside the casing according to claim 8, characterized in that, The main control chip processes the data. Specifically: Determine the correspondence between the magnetic field intensity and the casing clamp (8), the fiber optic clamp (7), and the armored optical fiber; the correspondence between the sensor label and the circumferential orientation of the pipeline; Based on the change trend of the magnetic field intensity corresponding to the fiber optic clamp (7) and the casing clamp (8), infer the position of the armored optical fiber in the circumferential direction; based on the acquired array data, analyze and verify the detection and identification performance of the downhole magnetic detector (10) for the armored optical fiber; conduct a comparative analysis of the detection effects of the metal casing (3), the casing clamp (8), the fiber optic clamp (7), and the armored optical fiber respectively.

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