Logging-while-drilling optical cable tension buffering device and using method thereof

Abstract

The invention provides a logging-while-drilling optical cable tension buffering device and a using method thereof.The device comprises an outer shell, an inner shell, an end base, a tension measuring mechanism, an elastic piece and an optical cable, the inner shell is arranged in the outer shell, and a cavity is formed between the inner shell and the outer shell; the outer shell and the inner shell are fixed with the end seat through screws, the tension measuring mechanism is arranged on the end seat, the elastic piece sleeves the outer side of the inner shell, and one end of the elastic piece is connected with the tension measuring mechanism; one end of the optical cable penetrates through the cavity, extends into the end base and is coupled with the signal transmission end of the tension measuring mechanism, logging information and tension information are transmitted to a well, the optical cable is wound on the outer side of the elastic piece and stretches out and draws back along with the elastic piece, and the device is compact in structure, small in occupied space and convenient to use. The optical cable can work normally under the conditions of severe underground environment and narrow space, the safety of the optical cable is protected through double vibration reduction, and the accurate transmission stability of logging information and the safety of the optical cable are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of logging optical cables, and particularly to a tension buffer device for logging-while-drilling optical cables and a method for using the same. Background Art

[0002] Logging-while-drilling fiber optic measurement is an innovative logging technology. Optical cable communication has a larger capacity and wider bandwidth than ordinary cable communication, and is suitable for the transmission of high-speed and broadband information; the loss of optical cables is very small, which can greatly increase the transmission distance without repeaters; optical cable communication transmits optical signals, hardly radiates outward, has relatively superior confidentiality performance, and at the same time will not cause crosstalk between the optical fibers in the same optical cable and is not affected by electromagnetic interference; it promotes the development of intelligent drilling and completion technology and provides strong technical support for the safe and efficient development of complex oil and gas resources.

[0003] The wire and cable buffer take-up and stranding equipment with the publication number CN118155942A reveals that the buffer damping device of the cable is located at the pay-off end, has a relatively large structure, and cannot buffer the stress condition of the downhole cable; although the submarine cable center positioning component and the submarine cable protection device in the publication number CN221227093U can move along with the cable, they have a relatively large structure and cannot work properly under the condition of harsh downhole environment and small space, and they can only meet the function of buffering and reducing the tension of the optical cable, and cannot obtain the current tension information. When the tension exceeds a certain value, there is still a crisis of optical cable breakage, making it difficult to guarantee the reliability of the optical cable, thereby reducing the stability of drilling measurement data transmission. Summary of the Invention

[0004] In view of this, the present invention proposes a tension buffer device for logging-while-drilling optical cables and a method for using the same, which has a compact structure and occupies a small space, can work properly under the condition of harsh downhole environment and small space, and moreover, protects the safety of the optical cable through double vibration damping, ensuring the accurate transmission stability of logging information and the safety of the optical cable.

[0005] The technical solution of the present invention is realized as follows: In the first aspect, the present invention provides a tension buffer device for logging-while-drilling optical cables, including an outer housing, an inner housing, end seats, a tensile force measuring mechanism, an elastic member, and an optical cable. Among them,

[0006] The inner housing is arranged inside the outer housing and is spaced from the inner wall of the outer housing, and a cavity is formed between the inner housing and the outer housing; both the outer housing and the inner housing are fixed to the end seats by screws;

[0007] The tensile force measuring mechanism is arranged on the end seat and is located inside the cavity, and the signal transmission end of the tensile force measuring mechanism penetrates and extends into the end seat;

[0008] The elastic member is sleeved outside the inner housing, and one end of the elastic member is connected to the tensile force measuring mechanism;

[0009] One end of the optical cable penetrates through the cavity and extends into the end seat, and is coupled with the signal transmission end of the tensile force measuring mechanism to transmit the logging information and the tensile force information to the wellhead. Moreover, the optical cable is wound around the outside of the elastic member and expands and contracts with the elastic member.

[0010] On the basis of the above technical solution, preferably, the outer housing, the inner housing and the end seat are coaxially arranged, and the end seat is provided with symmetrically arranged mounting holes. The tensile force measuring mechanism is fixed in one mounting hole, and a sealing assembly is arranged in the other mounting hole. One end of the optical cable sequentially penetrates through the cavity and the sealing assembly and extends into the end seat. The sealing assembly is used to seal between the optical cable and the mounting hole.

[0011] On the basis of the above technical solution, preferably, the tensile force measuring mechanism includes a head, a pull rod member, a pull rod seat and a measuring optical fiber. Among them, one end of the head is fixed in the mounting hole, and the other end is fixed to the pull rod member; the pull rod seat is threadedly connected to the end of the pull rod member away from the head, and one end of the elastic member close to the end seat is fixed to the pull rod seat;

[0012] A through hole is opened at the center of one side end face of the head, which penetrates through the pull rod member and extends to the end face of the pull rod seat. One end of the measuring optical fiber sequentially penetrates through the through holes of the head and the pull rod member and is fixed on the surface of the pull rod member, and the other end penetrates through the corresponding mounting hole and extends into the end seat for measuring the tensile force value signal of the optical cable.

[0013] On the basis of the above technical solution, preferably, the pull rod member is provided with a plurality of notches. The plurality of notches are arranged at equal intervals along the axial direction of the pull rod member, and the opening directions of two adjacent notches are opposite, and the plurality of notches are all communicated with the through hole for strengthening the elasticity of the pull rod member.

[0014] On the basis of the above technical solution, preferably, the sealing assembly includes a connecting member, a sealing screw tail, a sealing washer and a sealing sleeve. Among them,

[0015] The connecting member is inserted into the other mounting hole, and the sealing sleeve is sleeved on the outside of the connecting member and abuts against the inner wall of the mounting hole to seal the connection between the connecting member and the mounting hole; the inside of the connecting member is hollow, and a convex platform portion is arranged inside the connecting member;

[0016] The sealing washer abuts against the inside of the convex platform portion. The sealing screw tail is embedded on the side of the connecting member away from the mounting hole, and the sealing screw tail can linearly move along the axial direction of the connecting member and abuts against the surface of the sealing washer;

[0017] One end of the optical cable sequentially penetrates through the sealing screw tail and the sealing washer and extends into the end seat.

[0018] On the basis of the above technical solutions, preferably, the sealed screw tail is provided with an outward convex part, and the inner side of the connecting piece is provided with an inward concave part. The outer contour shape of the outward convex part matches the inner contour shape of the inward concave part, and the surfaces of the outward convex part and the inward concave part are in contact with each other, so that the sealed screw tail slides in the connecting piece to squeeze the sealing gasket and cause deformation.

[0019] On the basis of the above technical solutions, preferably, the elastic member includes a hooked section and a threaded section. Among them, the hooked section is fixedly connected to the threaded end, and the hooked section corresponds to the position of the pull rod seat and is fixed to the pull rod seat; the threaded section is sleeved on the outer side of the inner housing, and the optical cable is wound and bonded on the outer side along the extending direction of the threaded section and expands and contracts with the elastic member.

[0020] On the basis of the above technical solutions, preferably, it further includes an upper cover and a kit. Among them,

[0021] The upper cover is fixedly connected to the kit by bolts, and the other side of the upper cover is threadedly connected to the external wire bin for selectively paying out or taking in the wire according to the measured tensile force value signal;

[0022] The kit is arranged at one end of the outer housing away from the end seat, and the kit is fixedly connected to the outer housing and the inner housing by bolts;

[0023] The kit is provided with a wire hole, and the relative position of the wire hole is between the outer housing and the inner housing. The optical cable passes through the wire hole and extends into the cavity.

[0024] On the basis of the above technical solutions, preferably, it further includes a piston member and a sealing oil pin. Among them, the piston member is slidably arranged in the inner housing, and a threaded hole is opened at the center of the piston member. The sealing oil pin is threadedly connected in the threaded hole to prevent mud from entering the interior of the inner housing.

[0025] In a second aspect, the present invention also provides a usage method of a coiled tubing logging optical cable tension buffer device, which is realized by using the coiled tubing logging optical cable tension buffer device. The method includes the following steps:

[0026] S1. The optical cable passing through the wire hole passes through the upper cover and is connected to the pay-out end of the external wire bin;

[0027] S2. When the optical cable is subjected to a large impact, the elastic member will be stretched and deformed together with the optical cable. The elastic member pulls the pull rod seat connected thereto, and the measuring optical fiber measures the current tensile force value in real time;

[0028] S3. Measure the coupling of the optical fiber and the optical cable within the end socket, transmit the signal to the ground information processing terminal, compare the currently measured tensile force value with a preset tensile force threshold value. If the currently measured tensile force value is greater than the preset tensile force threshold value, the ground information processing terminal sends a wire release control to the external wire bin to increase the released length of the optical cable, so that the currently measured tensile force value gradually decreases until it reaches the preset tensile standard value;

[0029] S4. When the currently measured tensile force value is 0, the elastic member starts to retract under the action of its own elastic force. The retraction of the elastic member drives the optical cable wound around it to perform a wire winding operation until the optical cable and the elastic member are completely restored to the initial state.

[0030] A kind of optical cable tension buffer device for logging while drilling and its usage method according to the present invention have the following beneficial effects compared with the prior art:

[0031] (1) By winding and fixing the optical cable on the outside of the elastic member to achieve a parallel structure, the stretching deformation of the elastic member can effectively reduce the influence of vibration on the overall transmission link, greatly improving the upper limit that the optical cable can withstand. At the same time, the tensile force measuring mechanism will measure the currently measured tensile force value according to the deformation degree of the elastic member, and control the wire bin to release and wind the wire through signal transmission, further reducing the risk of optical cable breakage, achieving double vibration damping to protect the safety of the optical cable and ensuring the accurate transmission of logging information and the safety of the optical cable;

[0032] (2) By opening a number of notches on the pull rod member, the overall elastic deformation amount of the pull rod member is increased, and its sensitivity to tensile force changes is improved, enabling the tensile force measuring mechanism to more accurately reflect the tensile force situation of the optical cable. Moreover, the opening directions of two adjacent notches are opposite, enabling the pull rod member to distribute stress more evenly during elastic deformation, improving the service life and reliability of the pull rod member;

[0033] (3) By setting the sealing component, piston member and sealing oil pin, it can not only prevent the leakage of lubricating oil medium, but also prevent external impurities such as dust, moisture, and mud from entering the inner housing and the end socket, ensuring the accuracy and stability of signal transmission;

[0034] (4) By winding and bonding the optical cable along the extending direction of the threaded section on its outside, it can prevent the optical cable from loosening or falling off during the logging while drilling process; secondly, the threaded structure of the threaded section provides a guide for the winding of the optical cable, enabling the optical cable to be wound neatly and orderly on the outside of the elastic member, avoiding the mess of the optical cable. At the same time, it can automatically wind up the optical cable after the tensile force disappears; ensuring the stability and reliability of the optical cable during the logging while drilling process. Description of the Drawings

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0036] Figure 1 Isometric view of the wireline logging optical cable tension buffer device of the present invention;

[0037] Figure 2 Side view of the wireline logging optical cable tension buffer device of the present invention;

[0038] Figure 3 For the wireline logging optical cable tension buffer device of the present invention Figure 2 Cross-sectional view taken along line A-A;

[0039] Figure 4 For the wireline logging optical cable tension buffer device of the present invention Figure 3 Partial enlarged schematic view at B;

[0040] Figure 5 For the wireline logging optical cable tension buffer device of the present invention Figure 3 Partial enlarged schematic view at C;

[0041] Figure 6 Isometric view of the tension measurement mechanism of the wireline logging optical cable tension buffer device of the present invention;

[0042] Figure 7 Cross-sectional view of the tension measurement mechanism of the wireline logging optical cable tension buffer device of the present invention;

[0043] Figure 8 Structural schematic view of the elastic member of the wireline logging optical cable tension buffer device of the present invention;

[0044] Figure 9 Isometric view of the sealing assembly of the wireline logging optical cable tension buffer device of the present invention;

[0045] Figure 10 Cross-sectional view of the sealing assembly of the wireline logging optical cable tension buffer device of the present invention;

[0046] Figure 11 For the wireline logging optical cable tension buffer device of the present invention Figure 10 Partial enlarged schematic view at D;

[0047] Figure 12 For the wireline logging optical cable tension buffer device of the present invention Figure 2 Partial cross-sectional view. Detailed implementation mode

[0048] Next, in combination with the implementation mode of the present invention, the technical solutions in the implementation mode of the present invention will be clearly and completely described. Obviously, the described implementation mode is only a part of the implementation modes of the present invention, rather than all of the implementation modes. Based on the implementation modes in the present invention, all other implementation modes obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0049] As Figures 1-12 shown, a tension buffering device for a logging-while-drilling optical cable of the present invention includes an outer housing 1, an inner housing 2, an end seat 3, a tensile force measuring mechanism 4, an elastic member 5, and an optical cable 6. Among them, the inner housing 2 is arranged inside the outer housing 1 and is spaced from the inner wall of the outer housing 1, and a cavity 100 is formed between the inner housing 2 and the outer housing 1; both the outer housing 1 and the inner housing 2 are fixed to the end seat 3 by screws; the tensile force measuring mechanism 4 is arranged on the end seat 3 and is located inside the cavity 100, and the signal transmission end of the tensile force measuring mechanism 4 penetrates and extends into the end seat 3; the elastic member 5 is sleeved outside the inner housing 2, and one end of the elastic member 5 is connected to the tensile force measuring mechanism 4; one end of the optical cable 6 penetrates the cavity 100 and extends into the end seat 3, and is coupled with the signal transmission end of the tensile force measuring mechanism 4 to transmit logging information and tensile force information to the wellhead, and the optical cable 6 is wound outside the elastic member 5 and expands and contracts with the elastic member 5.

[0050] It should be noted that when the optical cable 6 is subjected to a large impact force during the logging-while-drilling process, the elastic member 5 will be stretched together with the optical cable 6. The stretching of the elastic member 5 will drive the tensile force measuring mechanism 4 connected thereto to change. The tensile force measuring mechanism 4 will measure the current tensile force value according to the deformation degree of the elastic member 5. The tensile force measuring mechanism 4 transmits the measured tensile force value signal to the optical cable 6 through its signal transmission end, and transmits the logging information and the tensile force information to the ground information processing terminal at the wellhead together. After receiving the tensile force value signal, the ground information processing terminal analyzes and processes the signal; if the measured current tensile force value is greater than the preset tensile force threshold, the ground information processing terminal will send a control instruction to the external wire bin to control the external wire bin to perform a wire release operation to reduce the tensile force on the optical cable 6; when the measured current tensile force value is 0, the elastic member 5 starts to retract under the action of its own elastic force, driving the optical cable 6 wound thereon to perform a wire retraction operation until it returns to the initial state.

[0051] In this embodiment, the optical cable 6 is wound and fixed on the outside of the elastic member 5 to achieve a parallel structure. When the optical cable 6 is subjected to a large tensile force, the tensile deformation of the elastic member 5 can absorb part of the energy, effectively reducing the impact of vibration on the overall transmission link, greatly increasing the upper limit of the optical cable 6's bearing capacity, improving the service life and reliability of the optical cable 6. At the same time, the tensile force measuring mechanism 4 measures the current tensile force value according to the deformation degree of the elastic member 5. Through signal transmission, it controls the winding and unwinding of the wire storage bin, further reducing the risk of the optical cable 6 breaking, achieving double vibration damping to protect the safety of the optical cable 6. Even in a harsh drilling environment, it can ensure the accurate transmission of logging information and the safe use of the optical cable, improving the success rate and reliability of the logging-while-drilling operation.

[0052] In this embodiment, the outer housing 1, the inner housing 2, and the end seat 3 are all coaxially arranged. The end seat 3 is provided with symmetrically arranged mounting holes 300. The tensile force measuring mechanism 4 is fixed in one mounting hole 300, and a sealing component 7 is arranged in the other mounting hole 300. One end of the optical cable 6 sequentially passes through the cavity 100 and the sealing component 7 and extends into the end seat 3. The sealing component 7 is used to seal between the optical cable 6 and the mounting hole 300.

[0053] It should be noted that the coaxial arrangement of the outer housing 1, the inner housing 2, and the end seat 3 makes the structure of the entire device more regular, the space utilization more reasonable, helps to reduce the volume of the device, making it easier to install and arrange in the limited space of the drilling equipment, and improving the adaptability of the device to the drilling equipment.

[0054] It can be understood that lubricating oil is injected between the inner housing 2 and the end seat 3 to prevent the lubricating oil from flowing into the end seat 3 from the mounting hole 300. Therefore, a sealing component 7 needs to be arranged between the optical cable 6 and the mounting hole 300 to prevent the leakage of the lubricating oil medium inside the device and maintain the normal working environment inside the device.

[0055] The tensile force measuring mechanism 4 in this embodiment includes a head 41, a pull rod member 42, a pull rod seat 43, and a measuring optical fiber 44. Among them, one end of the head 41 is fixed in the mounting hole 300, and the other end is fixed to the pull rod member 42; the pull rod seat 43 is threadedly connected to the end of the pull rod member 42 away from the head 41, and one end of the elastic member 5 close to the end seat 3 is fixed to the pull rod seat 43; a through hole 410 is opened at the center of one side end face of the head 41, passing through the pull rod member 42 and extending to the end face of the pull rod seat 43. One end of the measuring optical fiber 44 sequentially passes through the through hole 410 of the head 41 and the pull rod member 42 and is fixed on the surface of the pull rod member 42, and the other end passes through the corresponding mounting hole 300 and extends into the end seat 3 for measuring the tensile force value signal of the optical cable 6.

[0056] It should be noted that the head 41 matches the size of the corresponding mounting hole 300, and the two are sealed and connected to prevent lubricating oil from flowing into the end seat 3 through the mounting hole 300. During the logging-while-drilling process, the device will be subjected to various external forces. The tensile force is transmitted to the elastic member 5 through the optical cable 6, then from the elastic member 5 to the pull rod seat 43, and then through the pull rod member 42 to the head 41. This force transmission path enables the tensile force to accurately act on the tensile force measuring mechanism 4. Moreover, one end of the measuring optical fiber 44 sequentially penetrates through the through hole 410 of the head 41 and the pull rod member 42 and is fixed on the surface of the pull rod member 42, so that the measuring optical fiber 44 can directly sense the deformation of the pull rod member 42. The deformation of the pull rod member 42 will cause a change in the optical signal in the measuring optical fiber 44. By detecting the change in the optical signal, the tensile force value received by the optical cable 6 can be accurately calculated, improving the accuracy of tensile force measurement.

[0057] In this embodiment, the pull rod member 42 is provided with a plurality of notches 420. The plurality of notches 420 are arranged at equal intervals along the axial direction of the pull rod member 42, and the opening directions of two adjacent notches 420 are opposite, and the plurality of notches 420 are all communicated with the through hole 410 to strengthen the elasticity of the pull rod member 42.

[0058] It should be noted that the plurality of notches 420 are arranged at equal intervals along the axial direction of the pull rod member 42, so that the pull rod member 42 can more easily undergo elastic deformation when subjected to a tensile force. The design of the notches 420 is equivalent to forming a plurality of weak links on the pull rod member 42. When a tensile force is applied, these weak links will preferentially deform, thereby increasing the overall elastic deformation amount of the pull rod member 42.

[0059] It can be understood that, compared with a solid pull rod member without notches 420, in this embodiment, by designing the pull rod member 42 with notches, a greater deformation can be generated under the same tensile force, improving its sensitivity to tensile force changes, so that the tensile force measuring mechanism 4 can more accurately reflect the tensile force condition of the optical cable 6. Moreover, the opening directions of two adjacent notches 420 are opposite, so that the pull rod member 42 can distribute stress more evenly during elastic deformation. When a tensile force acts on the pull rod member 42, the notches 420 with different opening directions will restrict and coordinate with each other, avoiding the occurrence of stress concentration. Furthermore, the uniform stress distribution not only improves the load-bearing capacity of the pull rod member 42, but also makes its elastic deformation more stable, reducing the problems of local damage or uneven deformation caused by stress concentration, thereby improving the service life and reliability of the pull rod member 42.

[0060] In addition, a plurality of notches 420 are all communicated with the perforations 410. When the tensile force is transmitted to the tension rod member 42 through the optical cable 6, the area around the perforations 410 will preferentially deform, and the presence of the notches 420 will guide this deformation to expand along the axial direction. Furthermore, the elastic deformation of the tension rod member 42 near the perforations 410 is more sensitive, and it can more accurately convert the change in tensile force into a signal change that can be sensed by the measurement optical fiber 44, improving the accuracy of tensile force measurement.

[0061] The sealing assembly 7 in this embodiment includes a connecting member 71, a sealing screw tail 72, a sealing washer 73, and a sealing sleeve 74. Among them, the connecting member 71 is inserted into another mounting hole 300, and the sealing sleeve 74 is sleeved on the outside of the connecting member 71 and abuts against the inner wall of the mounting hole 300, so that the connecting member 71 is hermetically connected to the mounting hole 300; the inside of the connecting member 71 is hollow, and a boss portion 710 is provided inside the connecting member 71; the sealing washer 73 abuts against the inner side of the boss portion 710, the sealing screw tail 72 is embedded on the side of the connecting member 71 away from the mounting hole 300, and the sealing screw tail 72 can linearly move along the axial direction of the connecting member 71, and the sealing screw tail 72 abuts against the surface of the sealing washer 73; one end of the optical cable 6 sequentially passes through the sealing screw tail 72 and the sealing washer 73 and extends into the end seat 3.

[0062] It should be noted that the sealing sleeve 74 is sleeved on the outside of the connecting member 71 and abuts against the inner wall of the mounting hole 300 to form a first seal, which can prevent lubricating oil from entering the end seat 3 through the gap between the connecting member 71 and the mounting hole 300; the sealing screw tail 72 can linearly move along the axial direction of the connecting member 71 and abuts against the surface of the sealing washer 73 to form a second seal. When the sealing screw tail 72 applies pressure to the sealing washer 73, the sealing washer 73 will undergo elastic deformation. The sealing washer 73 is made of an elastic material such as rubber and has good compressibility and recoverability. Under the action of pressure, the diameter of the sealing washer 73 will change, facilitating the optical cable 6 to pass through the sealing washer 73 and enter the end seat 3. After the optical cable 6 is installed in place, the sealing screw tail 72 is loosened, and the sealing washer 73 will elastically reset under the action of its own elastic force; the reset sealing washer 73 will fill the gap between the optical cable 6 and the inner wall of the connecting member 71, enhancing the sealing effect. It can not only prevent the lubricating oil medium from leaking from the inside of the connecting member 71, but also prevent foreign impurities such as dust, moisture, and mud from entering the end seat 3, ensuring the accuracy and stability of signal transmission.

[0063] An outer convex portion 720 is provided on the sealing screw tail 72 in this embodiment, and an inner concave portion 730 is provided on the inner side of the connecting member 71. The outer contour shape of the outer convex portion 720 matches the inner contour shape of the inner concave portion 730, and the surface of the outer convex portion 720 abuts against the surface of the inner concave portion 730, so that the sealing screw tail 72 slides in the connecting member 71 and squeezes the sealing washer 73 to deform.

[0064] It should be noted that when the sealed screw tail 72 slides within the connecting member 71, the surface of the convex portion 720 is in close contact with the concave portion 730, which not only provides guidance for the movement of the sealed screw tail 72, but also can accurately transmit the external force to the sealing gasket 73, improving the stability of the entire device.

[0065] The elastic member 5 in this embodiment includes a hooked section 51 and a threaded section 52. Among them, the hooked section 51 is fixedly connected to the threaded end 52, and the hooked section 51 corresponds to the position of the pull rod seat 43 and is fixed to the pull rod seat 43; the threaded section 52 is sleeved on the outer side of the inner housing 2, and the optical cable 6 is wound and bonded on the outer side along the extending direction of the threaded section 52 and expands and contracts with the elastic member 5.

[0066] It should be noted that the elastic member 5 is composed of a hooked section 51 and a threaded section 52, and the two are fixedly connected to form a whole. The position of the hooked section 51 corresponds to that of the pull rod seat 43, and the hooked section 51 is fixed to the pull rod seat 43, enabling the elastic member 5 to be stably connected to the pull rod seat 43 and providing a reliable support point for subsequent expansion and contraction actions; the optical cable 6 is wound and bonded on the outer side along the extending direction of the threaded section 52, which can firmly fix the optical cable 6 on the elastic member 5 and prevent the optical cable 6 from loosening or falling off during the logging-while-drilling process; secondly, the threaded structure of the threaded section 52 provides guidance for the winding of the optical cable 6, enabling the optical cable 6 to be wound neatly and orderly on the outer side of the elastic member 5, avoiding the mess of the optical cable 6 and reducing the possibility of the optical cable 6 rubbing against and winding around each other during the expansion and contraction process. At the same time, when the tensile force is 0, the automatic winding function of the elastic member 5 brings great convenience to the operation and maintenance of the device; since the optical cable 6 is wound neatly and orderly on the outer side of the threaded section 52, under the action of its own elastic force, the elastic member 5 can automatically wind up the optical cable 6; ensuring the stability and reliability of the optical cable 6 during the logging-while-drilling process.

[0067] This embodiment further includes an upper cover 8 and a kit 9. Among them, the upper cover 8 is fixedly connected to the kit 9 by bolts, and the other side of the upper cover 8 is threadedly connected to an external wire bin for selectively paying out or taking in wire according to the measured tensile force value signal; the kit 9 is arranged at one end of the outer housing 1 away from the end seat 3, and the kit 9 is fixedly connected to the outer housing 1 and the inner housing 2 by bolts; a wire hole 900 is provided on the kit 9, and the relative position of the wire hole 900 is located between the outer housing 1 and the inner housing 2, and the optical cable 6 passes through the wire hole 900 and extends into the cavity 100.

[0068] It should be noted that the kit 9 is arranged at one end of the outer housing 1 away from the end seat 3, and is fixedly connected to the outer housing 1 and the inner housing 2 by bolts, so that the kit 9 plays an important supporting and connecting role in the whole device; it firmly connects the outer housing 1 and the inner housing 2 together, enhancing the overall structural stability of the device; at the same time, the kit 9 serves as the connection foundation for the upper cover 8, providing reliable support for the installation of the upper cover 8.

[0069] This embodiment further includes a piston member 10 and an oil sealing pin 11. Among them, the piston member 10 is slidably arranged inside the inner housing 2, and a threaded hole 140 is provided at the center of the piston member 10. The oil sealing pin 11 is threadedly connected to the threaded hole 140 to prevent mud from entering the interior of the inner housing 2.

[0070] It should be noted that the piston member 10 is slidably arranged inside the inner housing 2. During the logging-while-drilling process, the piston member 10 can move accordingly according to the internal pressure. The oil sealing pin 11 is threadedly connected to the threaded hole 140. This sealing structure can effectively prevent external liquids such as mud from entering the interior of the inner housing 2, protecting the interior of the inner housing 2 from being eroded and damaged by mud, and ensuring the stability of the internal environment of the device.

[0071] It can be understood that in different drilling environments and working conditions, the composition and pressure of the mud may vary. The reliable sealing function of the oil sealing pin 11 enables the device to adapt to various complex mud environments, ensuring the normal operation of the device under different conditions. Whether in shallow wells, deep wells or in high-temperature, high-pressure drilling environments, the oil sealing pin 11 can effectively protect the internal components of the inner housing 2.

[0072] The structure of this embodiment is compact. The main components are only the elastic member 5 that plays a buffering role and the tension rod member 42 for measuring tension. It occupies a small space and is easy to install, reducing the risk of failures and damages caused by environmental factors, reducing the maintenance and replacement costs. And during the winding and unwinding process of the wire bin, it will not affect the winding area of the optical cable 6 and the elastic member 5, making the operation of the optical cable more simple and flexible, improving the operation efficiency; moreover, the built-in elastic member 5 and the tension measuring mechanism 4 are not affected by electromagnetic interference, ensuring the stability of the optical cable and the buffering work under working conditions, enabling the device to work stably for a long time in the downhole environment of high temperature and high pressure. The tension measuring mechanism 4 is subsequently coupled to the optical cable 6 to achieve data transmission, and can real-time monitor the stress condition of the optical cable in complex environments, providing more accurate data support for drilling operations, and effectively ensuring the stability of drilling measurement data transmission.

[0073] In the second aspect, the present invention also provides a method for using a logging-while-drilling optical cable tension buffering device, which is implemented by using the logging-while-drilling optical cable tension buffering device. The method includes the following steps:

[0074] S1. The optical cable 6 passing through the wire hole 900 passes through the upper cover 8 and is connected to the wire releasing end of the external wire bin.

[0075] S2. When the optical cable 6 is subjected to a large impact, the elastic member 5 will be stretched and deformed together with the optical cable 6. The elastic member 5 pulls the connecting rod seat 43, and the measuring optical fiber 44 measures the current tensile force value in real time.

[0076] S3. The measuring optical fiber 44 is coupled with the optical cable 6 in the end seat 3, and the signal is transmitted to the ground information processing end. The current measured tensile force value is compared with the preset tensile force threshold. If the current measured tensile force value is greater than the preset tensile force threshold, the ground information processing end sends a wire releasing control to the external wire bin to increase the release length of the optical cable 6, so that the current measured tensile force value gradually decreases until it reaches the preset tensile force standard value.

[0077] S4. When the current measured tensile force value is 0, the elastic member 5 starts to retract under the action of its own elastic force. The retraction of the elastic member 5 drives the optical cable 6 wound thereon to perform a wire winding operation until the optical cable 6 and the elastic member 5 are completely restored to the initial state.

[0078] It should be noted that the optical cable 6 is slowly passed through the wire hole 900 to avoid excessive bending or pulling of the optical cable 6 and prevent damage to the optical fiber inside the optical cable 6. Then, the end of the passed optical cable 6 is connected to the wire releasing end of the external wire bin; during the logging-while-drilling process, when the optical cable 6 is subjected to a large impact, the elastic member 5 will immediately respond and undergo tensile deformation together with the optical cable 6. The tensile deformation of the elastic member 5 will pull the connecting rod seat 43, and the movement of the connecting rod seat 43 will drive the measurement optical fiber 44 to undergo corresponding deformation. The measurement optical fiber 44 measures the current tensile force value in real time, and its measurement principle is based on the strain effect of the optical fiber, that is, when the optical fiber is subjected to a tensile force, it will deform, resulting in a change in the characteristics of the optical signal. By detecting this change, the tensile force value can be obtained; the measurement optical fiber 44 transmits the measured tensile force signal to the end seat 3, where the signal is processed and coupled, and then the signal is transmitted to the ground information processing end through a dedicated communication line; after receiving the tensile force signal, the ground information processing end will compare the measured current tensile force value with a preset tensile force threshold; if the measured current tensile force value is greater than the preset tensile force threshold, the ground information processing end will immediately send a wire releasing control signal to the external wire bin. After receiving the signal, the external wire bin will increase the release length of the optical cable 6 to gradually reduce the tensile force on the optical cable 6. During the wire releasing process, the ground information processing end will continuously monitor the change in the tensile force value until the measured current tensile force value gradually decreases to the preset tensile force standard value; when the measured current tensile force value is 0, at this time, the elastic member 5 begins to retract under the action of its own elastic force. The retraction of the elastic member 5 will drive the optical cable 6 wound thereon to perform a wire retracting operation. During the wire retracting process, the optical cable 6 will be wound and recovered orderly along the threaded section 52 of the elastic member 5, avoiding the chaos of the optical cable 6; the optical cable 6 and the elastic member 5 are completely restored to the initial state.

[0079] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. 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 tension buffer device for logging-while-drilling optical cable, characterized in that It includes an outer housing (1), an inner housing (2), an end seat (3), a tensile force measuring mechanism (4), an elastic member (5) and an optical cable (6). Among them, the inner housing (2) is arranged inside the outer housing (1) and is spaced from the inner wall of the outer housing (1). A cavity (100) is formed between the inner housing (2) and the outer housing (1); both the outer housing (1) and the inner housing (2) are fixed to the end seat (3) by screws; the tensile force measuring mechanism (4) is arranged on the end seat (3) and is located inside the cavity (100). The signal transmission end of the tensile force measuring mechanism (4) penetrates and extends into the end seat (3); the elastic member (5) is sleeved outside the inner housing (2), and one end of the elastic member (5) is connected to the tensile force measuring mechanism (4); one end of the optical cable (6) penetrates the cavity (100) and extends into the end seat (3), is coupled with the signal transmission end of the tensile force measuring mechanism (4), and transmits well logging information and tensile force information to the wellhead. Moreover, the optical cable (6) is wound outside the elastic member (5) and expands and contracts with the elastic member (5).

2. The logging-while-drilling optical cable tension buffer device according to claim 1, characterized in that: The outer housing (1), the inner housing (2) and the end seat (3) are coaxially arranged. The end seat (3) is provided with symmetrically arranged mounting holes (300). The tensile force measuring mechanism (4) is fixed in one mounting hole (300), and a sealing assembly (7) is arranged in the other mounting hole (300). One end of the optical cable (6) sequentially penetrates the cavity (100) and the sealing assembly (7) and extends into the end seat (3). The sealing assembly (7) is used to seal between the optical cable (6) and the mounting hole (300).

3. The wireline logging optical cable tension buffer device according to claim 2, wherein: The tensile force measuring mechanism (4) includes a head (41), a pull rod member (42), a pull rod seat (43) and a measuring optical fiber (44). Among them, one end of the head (41) is fixed in the mounting hole (300), and the other end is fixed to the pull rod member (42); the pull rod seat (43) is threadedly connected to the end of the pull rod member (42) away from the head (41), and one end of the elastic member (5) close to the end seat (3) is fixed to the pull rod seat (43); a through hole (410) is opened at the center of one side end face of the head (41) and extends through the pull rod member (42) to the end face of the pull rod seat (43). One end of the measuring optical fiber (44) sequentially penetrates the head (41) and the through hole (410) of the pull rod member (42), and is fixed on the surface of the pull rod member (42), and the other end penetrates the corresponding mounting hole (300) and extends into the end seat (3) for measuring the tensile force value signal of the optical cable (6).

4. The wireline logging optical cable tension buffer device according to claim 3, characterized in that: The pull rod member (42) is provided with a plurality of notches (420). The plurality of notches (420) are arranged at equal intervals along the axial direction of the pull rod member (42), and the opening directions of two adjacent notches (420) are opposite, and the plurality of notches (420) are all communicated with the through hole (410) to strengthen the elasticity of the pull rod member (42).

5. The logging-while-drilling optical cable tension buffer device according to claim 2, wherein: The sealing assembly (7) includes a connecting member (71), a sealing screw tail (72), a sealing washer (73) and a sealing sleeve (74). Among them, The connecting piece (71) is inserted into another mounting hole (300), and the sealing sleeve (74) is sleeved on the outside of the connecting piece (71) and abuts against the inner wall of the mounting hole (300), so that the connecting piece (71) is hermetically connected to the mounting hole (300); the inside of the connecting piece (71) is hollow, and a boss portion (710) is provided inside the connecting piece (71); The sealing washer (73) abuts against the inner side of the boss portion (710), the sealing screw tail (72) is embedded on the side of the connecting piece (71) away from the mounting hole (300), and the sealing screw tail (72) can linearly move along the axial direction of the connecting piece (71), and the sealing screw tail (72) abuts against the surface of the sealing washer (73); One end of the optical cable (6) sequentially passes through the sealing screw tail (72) and the sealing washer (73) and extends into the end seat (3).

6. The logging-while-drilling optical cable tension buffer device according to claim 5, characterized in that: An outward convex portion (720) is provided on the sealing screw tail (72), and an inward concave portion (730) is provided on the inner side of the connecting piece (71). The outer contour shape of the outward convex portion (720) matches the inner contour shape of the inward concave portion (730), and the surface of the outward convex portion (720) abuts against the surface of the inward concave portion (730), so that the sealing screw tail (72) slides in the connecting piece (71) to squeeze the sealing washer (73) to deform.

7. The wireline logging optical cable tension buffer device according to claim 1, wherein: The elastic member (5) includes a hook section (51) and a threaded section (52). Among them, the hook section (51) is fixedly connected to the threaded end (52), and the hook section (51) corresponds to the position of the pull rod seat (43), and the hook section (51) is fixed to the pull rod seat (43); the threaded section (52) is sleeved on the outside of the inner housing (2), and the optical cable (6) is wound and bonded on the outside along the extending direction of the threaded section (52) and expands and contracts with the elastic member (5).

8. The logging-while-drilling optical cable tension buffer device according to claim 1, wherein: It further includes an upper cover (8) and a kit (9), where, The upper cover (8) is fixedly connected to the kit (9) by bolts, and the other side of the upper cover (8) is threadedly connected to the external wire bin, and is used for selectively paying out or taking in the wire according to the measured tension value signal; The kit (9) is arranged at one end of the outer housing (1) away from the end seat (3), and the kit (9) is fixedly connected to the outer housing (1) and the inner housing (2) by bolts; A wire hole (900) is provided on the kit (9), and the relative position of the wire hole (900) is located between the outer housing (1) and the inner housing (2), and the optical cable (6) passes through the wire hole (900) and extends into the cavity (100).

9. The wireline logging optical cable tension buffer device according to claim 1, wherein: It further includes a piston member (10) and an oil sealing pin (11). Among them, the piston member (10) is slidably arranged inside the inner housing (2), and a threaded hole (140) is provided at the center of the piston member (10), and the oil sealing pin (11) is threadedly connected to the threaded hole (140) to prevent mud from entering the inside of the inner housing (2).

10. A method for using an optical cable tension buffer device for logging while drilling, implemented by using the optical cable tension buffer device for logging while drilling according to any one of claims 1-9, characterized in that: The method includes the following steps: S1, the optical cable (6) passing out of the wire hole (900) passes through the upper cover (8) and is connected to the pay-out end of the external wire bin; S2. When the optical cable (6) is subjected to a large impact, the elastic member (5) will be stretched and deformed together with the optical cable (6). The elastic member (5) pulls the pull rod seat (43) connected thereto, and the measuring optical fiber (44) measures the current tensile force value in real time; S3. The measuring optical fiber (44) is coupled with the optical cable (6) in the end seat (3), and the signal is transmitted to the ground information processing terminal. The current measured tensile force value is compared with a preset tensile force threshold. If the current measured tensile force value is greater than the preset tensile force threshold, the ground information processing terminal sends a wire release control to the external wire bin to increase the release length of the optical cable (6), so that the current measured tensile force value gradually decreases until it reaches the preset tensile force standard value; S4. When the current measured tensile force value is 0, the elastic member (5) begins to retract under the action of its own elastic force. The retraction of the elastic member (5) drives the optical cable (6) wound thereon to perform a wire retraction operation until the optical cable (6) and the elastic member (5) are completely restored to the initial state.

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