Well logging electrode system for well wall coring

Abstract

A well logging electrode system for well wall coring comprises an upper connector, an upper connector connector, a lower connector, a lower connector connector, an outer insulation sleeve, an SP ring, insulation assemblies and an extension barrel, and the upper connector, the upper connector connector, the extension barrel, the lower connector connector, the lower connector and the two sets of insulation assemblies are correspondingly connected to form a structure body. The extension cylinder is electrically insulated from the upper connector, the upper interface connector, the lower connector and the lower interface connector through the insulation assembly, the outer insulation sleeve is arranged on the structure body in a sleeving mode and integrally covers the extension cylinder, the SP rings in the independent circular ring shapes are distributed on the outer insulation sleeve in a sleeving mode and are electrically insulated from the extension cylinder, and a wire connecting hole is formed in the extension cylinder. According to the electrode system, the insulation structure can be obviously simplified, the reliability of the overall insulation performance can be effectively improved, the production, installation, use and maintenance efficiency can be improved in practical application, and the labor intensity of workers can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of oil field well logging, in particular to a logging electrode system for well wall coring. Background Art

[0002] Natural potential logging is an important technical means for obtaining downhole reservoir structure information or geological parameters of oil-producing layers in oilfield production. Its basic method is to use a cable to lower the logging electrode system into the well to perform dynamic potential measurement and read the recorded potential change curve. The utility model patent with authorization announcement number CN214944202U discloses "a logging hard electrode with a detachable outer insulating sleeve". The SP ring joint with a columnar structure is used as the measuring electrode. The electrode has an annular detection surface exposed outside the outer insulating sleeve. Insulation components are respectively provided between the two ends and the upper and lower joints or extended connecting tubes, and insulation sealing is achieved by the structural combination of insulating components. To address issues such as low coring yields or missed cores during drilling, a logging cable is often used to run a coring device down the borehole wall to extract formation samples. Secondary sampling verifies the formation's lithology, oil content, and the relationship between lithology and electrical properties, or to meet other special geological requirements. To ensure sampling quality and calibrate sampling locations, a logging electrode system must be used during sidewall coring. Furthermore, due to the process requirements for sidewall coring, the logging electrode system must be equipped with multiple SP electrodes to ensure accurate sampling positioning. The installation of multiple SP electrodes inevitably requires a greater number of insulating connections. This increased number of insulating connections inevitably reduces the overall insulation reliability of the logging electrode system, increasing the risk of logging accidents and creating safety hazards. Furthermore, due to the complex structure of the insulating components and the precise assembly process requirements, the labor intensity during production, assembly, and maintenance of the logging electrode system increases, leaving work efficiency in need of improvement. Therefore, it is necessary to improve the conventional logging electrode system to address the existing technical issues. Summary of the Invention

[0003] The purpose of the utility model is to provide a logging electrode system for wellbore coring, simplify the insulation structure between the electrodes of the electrode system, improve the reliability of the insulation performance of the electrode system, optimize the wiring method of the electrode system and the connection method between the wiring and the electrodes, and improve the stability of the insulation performance of the electrode system.

[0004] A logging electrode system for coring a wellbore, comprising: an upper joint, an upper interface joint, a lower joint, a lower interface joint, an outer insulating sleeve, an SP ring, an insulating assembly, and an extended barrel. The upper joint, the upper interface joint, the insulating assembly, the extended barrel, the insulating assembly, the lower interface joint, and the lower joint are sequentially connected to form a structural main body. The extended barrel is electrically insulated from the upper joint, the upper interface joint, the lower joint, and the lower interface joint disposed at both ends of the structural main body by two sets of the insulating assemblies. The outer insulating sleeve is fitted onto the outer circumferential surface of the structural main body, entirely covering the extended barrel, thereby further strengthening and protecting the electrical insulation performance between the extended barrel and the upper joint and the lower joint. A core female socket is installed inside the upper joint, and a mechanical connection structure for connecting to a torpedo joint is provided at the upper end. A core male pin is installed inside the lower joint, and a sealing connection structure for connecting to relevant logging instruments is provided at the lower end. Several independent circular SP rings are axially distributed along the main body of the structure and are fixed on the outer circumference of the outer insulating sleeve to maintain electrical insulation from the extension cylinder. At the layout position of the SP ring, the extension cylinder is respectively provided with corresponding connection holes passing through the cylinder wall, and the outer insulating sleeve is provided with threaded mounting holes corresponding to the connection holes, so that the distribution wires in the extension cylinder can respectively pass through the connection holes and the threaded mounting holes to directly connect to each SP ring.

[0005] In the logging electrode system for coring the well wall, the SP ring is preferably an elastic ring body with an axial opening, and the elastic ring body can be elastically expanded at the axial opening. The SP ring can be fitted onto the outer insulating sleeve through the expanded axial opening. At the same time, a locking mechanism is provided on the axial opening, and the SP ring locking hoop can be fitted onto the outer insulating sleeve by locking the axial opening.

[0006] The logging electrode system for coring the well wall is preferably equipped with an inner insulating sleeve on the inner circumferential surface of the connecting hole. The inner insulating sleeve can be used to separate the connection point between the distribution wire and the SP ring relative to the extension cylinder, thereby providing insulation protection for the SP ring relative to the extension cylinder.

[0007] The logging electrode system for coring the well wall, preferably, the insulating component specifically includes: a connecting sleeve and an insulating component, the connecting sleeve is a connecting structural component, and has mechanical connection structures at both ends, which are respectively arranged and connected between the extension cylinder and the upper interface joint and the lower interface joint, and the insulating component is filled and arranged between the mating surfaces and corresponding mating surfaces of the connecting sleeve and the extension cylinder, the upper interface joint and the lower interface joint, and the insulating component is combined with each other to separate the connecting sleeve as a whole, so that the connecting sleeve is electrically insulated from the extension cylinder, the upper interface joint and the lower interface joint.

[0008] The logging electrode system for coring the well wall is preferably equipped with a wiring disk embedded in the upper joint, and a longitudinal through-hole is provided on the body of the wiring disk for guiding the through-wire passing through the extension cylinder. At the same time, a plurality of longitudinally connected terminal posts are distributed, and pluggable line connection mechanisms are respectively installed at both ends of the terminal posts. The universal terminal posts can reasonably distribute the power supply wires in the logging cable, facilitate the line connection of the SP ring and other electrical components, and ensure the safety and reliability of the line connection.

[0009] The beneficial effect of the present invention is that it provides an electrode system for coring from the well wall, which adopts an elastic independent annular split SP ring structure. The SP ring can be installed on the outer insulating sleeve or removed from the outer insulating sleeve by elastically opening the SP ring in the axial direction. The operation is simple and convenient, the labor intensity is low, and the production installation and use and maintenance efficiency are high. In addition, the SP ring is directly insulated from the extension barrel through the outer insulating sleeve, eliminating the structural performance requirements of the prior art that multiple groups of insulating components need to be set in the extension barrel. Only two groups of insulating components need to be set between the extension barrel and the upper interface joint and the lower interface joint, which reduces the insulation level on the extension barrel, significantly simplifies the insulation structure of the electrode system, and can effectively improve the overall insulation reliability of the electrode system. At the same time, on this basis, by optimizing the wiring and the connection method between the wiring and the SP ring, the stability of the insulation performance of the electrode system can be improved. Furthermore, by adding a wiring board to configure the power supply wire and its function, the female wiring pin and the male wiring pin can be plugged and matched to connect the connection line. The line connection is stable and reliable, which can avoid the hidden dangers of false connection accidents and ensure the reliability of the connection and the safety of production. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a diagram of the electrode system structure used for coring the wellbore.

[0011] Figure 2 for Figure 1 Cross-sectional view of the middle AA section.

[0012] Figure 3 for Figure 1Cross-sectional view of the middle BB section.

[0013] Figure 4 This is a structural diagram of the insulation component.

[0014] Figure 5 This is a schematic diagram of the wiring circuit of the logging electrode system used for wellbore coring.

[0015] Among them: 1 is the upper connector, 2 is the upper interface connector, 3 is the primary sleeve, 4 is the secondary sleeve, 5 is the tertiary sleeve, 6 is the lower connector, 7 is the lower interface connector, 8 is the outer insulating sleeve, 9 is the distribution board, 10 is the SP ring, 11 is the core female socket, 12 is the core male pin, 13 is the end connector, 14 is the inner insulating sleeve, 15 is the anti-filling, 16 is the connecting sleeve, 17 is the insulating component, 18 is the sealing plug, 19 is the locking sleeve, 20 is the insulating assembly, 21 is the fixing frame, 22 is the wiring screw, 23 is the connecting bolt, and 24 is the wiring male pin. DETAILED DESCRIPTION

[0016] Furthermore, the technical solution for which protection is sought in the present utility model is described in detail in conjunction with specific embodiments and the accompanying drawings.

[0017] A logging electrode system for coring wellbore, such as Figures 1 to 3 As shown, it is composed of an upper connector 1, an upper interface connector 2, an extension cylinder, a lower connector 6, a lower interface connector 7, an outer insulating sleeve 8, a distribution plate 9, an SP ring 10, a core female socket 11, a core male pin 12, an anti-filling 22 and an insulating component 20; wherein: the extension cylinder is composed of a primary sleeve 3, a secondary sleeve 4, a tertiary sleeve 5 and an end connector 13, the primary sleeve 3, the secondary sleeve 4 and the tertiary sleeve 5 are sequentially connected to each other as a whole, and the two end connectors 13 are respectively connected and installed at both ends of the connector. The outer insulating sleeve 8 is composed of a plurality of PEEK sleeves snap-fitted and connected together. The insulating component 20, as shown Figure 4 As shown, it consists of a connecting sleeve 16, an insulating component 17, a sealing plug 18 and a locking sleeve 19.

[0018] The inner part of the upper joint 1 is provided with the core female socket 11 and the wiring disk 9 is embedded therein. The wiring disk 9 is in the shape of a circular disk body and is fixed by a fixing frame 21. There are 10 axially connected terminal posts on the disk body. The two ends of the terminal posts are respectively provided with terminal male pins 24. A screw sleeve connection structure is provided at the upper end of the upper joint 1, and a connecting external thread is provided at the lower end; the upper interface joint 2 is threadedly connected to the lower end of the upper joint 1, and a threaded connection shaft with a reduced diameter is provided at the lower end of the upper interface joint 2 to form an annular connection end face; a connection hole with an aperture corresponding to the diameter of the threaded connection shaft on the upper interface joint 2 is provided on the upper end face of the connecting sleeve 16. The interior has an accommodating cavity with an enlarged aperture relative to the connecting hole, and a connecting internal thread is provided at the lower end. The threaded connecting shaft is fitted in the connecting hole, and the locking sleeve 19 is fitted in the accommodating cavity and threadedly mounted on the threaded connecting shaft inserted into the accommodating cavity. The connecting sleeve 16 is limitedly connected to the upper interface joint 2. After the connecting fitting surfaces between the connecting sleeve 16 and the upper interface joint 2 and the locking sleeve 19 are respectively filled with the insulating member 17, the locking sleeve 19 is tightened and the sealing plug 18 is sealed and embedded in the accommodating cavity. A set of the insulating components 20 can be insulated and sealed and connected to the upper interface joint 2. The core male pin 12 is installed inside the lower joint 7, and an external connecting thread and an internal connecting thread are respectively provided at the upper and lower ends; the lower interface joint 7 is threadedly connected to the upper end of the lower joint 6, and the anti-filling plug 22 is embedded in the inner cavity to seal the inner cavity space of the extended cylinder, and a threaded connection shaft with a reduced diameter is provided at the lower end of the lower interface joint 2 to form an annular connection end face, and another set of the insulating components 20 are installed on the lower interface joint 2 in an insulating and sealing connection. The upper and lower ends of the extension cylinder are respectively connected to the two groups of the insulating components 20 by threaded cooperation using the end connectors 13. The outer insulating sleeve 8 corresponds to the outer circumferential surface structure of the extension cylinder and the insulating component 20. The overall set covers the outer circumferential surface of the extension cylinder and the insulating component 20 and the connection seam area between the insulating component 20 and the upper interface connector 2 and the lower interface connector 7. Three SP rings 10 are arranged in the axial distribution of the extension cylinder, of which one is installed on the secondary sleeve 4 and two are installed on the tertiary sleeve 5. Corresponding to the installation position of the SP ring 10, wiring holes are respectively opened on the secondary sleeve 4 and the tertiary sleeve 5. The wiring holes are inlaid with inner insulating sleeves 14, and threaded mounting holes are correspondingly opened on the outer insulating sleeve 8. The SP ring 10 is a circular ring shape with an axial linear opening, such as Figure 2As shown, the axial straight opening can be connected and locked using three connecting bolts 23. A connecting hole is provided on the radially corresponding side of the axial straight opening. The connecting hole corresponds to the threaded mounting hole provided on the outer insulating sleeve 8. When the SP ring 10 is fitted onto the outer insulating sleeve 8, the SP ring 10 can be connected and mounted on the outer insulating sleeve 8 using the corresponding matching connection screws 22 and the threaded mounting holes. At the same time, the connection screws 22 extend into the wiring holes and are connected to the corresponding distribution wires, so that the SP ring 10 is connected to the working power supply.

[0019] The logging electrode system for coring the well wall described in this embodiment adopts a split-type SP ring 10 independently installed on the outside of the outer insulating sleeve 8, which can make the SP ring 10 directly insulated from the extension cylinder through the outer insulating sleeve 8 and directly connected to the cable conductor inside the extension cylinder. At the connection point, only an inner insulating sleeve 14 with a simple structure is required to effectively implement insulation protection for the connection point relative to the extension cylinder. Compared with the existing technology, the number of insulating components 20 with complex structures and cumbersome assembly on the extension cylinder is reduced to the maximum extent, which can reduce the number of insulation levels of the extension cylinder, improve the overall insulation reliability, and ensure production and application safety. Moreover, the SP ring 10 can be directly fitted onto the outer insulating sleeve 8 from the outside by utilizing the elastic expansion of its own ring body, and then the SP ring 10 is connected using the wiring screw 22 and locked using the connecting bolt 23. It is easy to disassemble and install, and is also conducive to improving the work efficiency of the production, installation, use and maintenance of the SP ring 10, and reducing the labor intensity of workers. At the same time, a wiring tray 9 is added, such as Figure 3 and Figure 5 As shown, the power supply cable bundle conductors in the logging cable are configured with lines and functions, and conductor No. 10 is preset as the grounding wire. One branch line conductor is branched from conductors No. 1 to 7, and three branch line conductors are branched from conductors No. 10. The 10 branch conductors are respectively equipped with female wiring pins. By utilizing the structure of the female wiring pins and the male wiring pins 24, the 10 branch conductors are respectively connected to the 10 terminal posts on the distribution board 9 in a pluggable manner. At the same time, the main line conductors No. 1 to 10 in the cable bundle conductors are bundled as through wires from the wire holes opened on the distribution board 9 and pass through the inner cavity of the logging electrode system for well wall coring and are led out from the lower joint 7 for connection with other instruments and devices connected to the lower part of the logging electrode system for well wall coring; wherein: the 10 branch conductors configured on the distribution board 9, as Figure 5As shown, one of the three No. 10 tap conductors is connected to the upper connector 1 and the lower connector 6 respectively, and the other two No. 10 tap conductors are used as grounding backup lines. Once the original tap conductor fails to ground or is disconnected, they can be replaced at any time to ensure normal power operation and avoid production accidents. Three tap conductors No. 3, 4, and 5 are randomly selected from the No. 1 to 7 tap conductors and connected to the three SP rings 10 respectively, and the remaining four tap conductors are used as power supply backup lines. When the original connection line fails, the power supply is continued at any time to ensure the normal power supply and operation of each SP ring 10 during production use; the connection ends of the power supply connection conductors of the three SP rings 10, the upper connector 1, and the lower connector 6 and the distribution board 9 are also respectively installed with the female terminal pins, so that the SP ring 10, the upper connector 1, and the lower connector 6 are all connected to the terminal post in a pluggable manner, which is convenient for connection and disconnection and improves the reliability and stability of the connection.

Claims

1. A logging electrode system for coring a wellbore, characterized in that: include: An upper joint (1), an upper interface joint (2), a lower joint (6), a lower interface joint (7), an outer insulating sleeve (8), an SP ring (10), an insulating component (20) and an extended cylinder. The upper joint (1), the upper interface joint (2), the insulating component (20), the extended cylinder, the insulating component (20), the lower interface joint (7) and the lower joint (6) are sequentially connected to form a structural main body. The extended cylinder is electrically insulated from the upper joint (1), the upper interface joint (2), the lower joint (6) and the lower interface joint (7) respectively arranged at two ends of the structural main body through two groups of the insulating components (20). The outer insulating sleeve (8) is fitted on the outer circumference of the structural main body and covers the extended cylinder as a whole. A core female socket (11) is installed inside the upper joint (1), and a mechanical connection structure is provided at the upper end; a core male pin (12) is installed inside the lower joint (6), and a sealing connection structure is provided at the lower end; a plurality of independent annular SP rings (10) are axially distributed along the main body of the structure and fixed on the outer circumferential surface of the outer insulating sleeve (8), and are electrically insulated from the extended cylinder; at the arrangement position of the SP ring (10), the extended cylinder is provided with corresponding connection holes penetrating the cylinder wall, and the outer insulating sleeve (8) is provided with threaded mounting holes corresponding to the connection holes, so that the distribution wires in the extended cylinder can pass through the connection holes and the threaded mounting holes respectively and directly connect to the SP ring (10).

2. A logging electrode system for coring a wellbore according to claim 1, characterized in that: The SP ring (10) is an elastic ring body with an axial opening. The elastic ring body can be elastically expanded at the axial opening. The SP ring (10) can be sleeved onto the outer insulating sleeve (8) through the expanded axial opening. At the same time, a locking mechanism is provided on the axial opening. By locking the axial opening, the SP ring (10) can be locked onto the outer insulating sleeve (8).

3. A logging electrode system for coring a wellbore according to claim 2, characterized in that: An inner insulating sleeve (14) is embedded on the inner circumferential surface of the connection hole, and the inner insulating sleeve (14) can be used to separate the connection point between the distribution wire and the SP ring (10) relative to the extension cylinder.

4. A logging electrode system for coring a wellbore according to claim 3, characterized in that: The insulating assembly (20) specifically comprises: a connecting sleeve (16) and an insulating member (17), wherein the connecting sleeve (16) is a connecting structural member, and has mechanical connection structures at both ends, which are respectively arranged and connected between the extension cylinder and the upper interface joint (2) and the lower interface joint (7), and the insulating member (17) is filled and arranged between the mating surfaces and mating corresponding surfaces of the connecting sleeve (16) and the extension cylinder, the upper interface joint (2) and the lower interface joint (7). The insulating members (17) are combined with each other to separate the connecting sleeve (16) as a whole, so that the connecting sleeve (16) is electrically insulated from the extension cylinder, the upper interface joint (2) and the lower interface joint (7).

5. The logging electrode system for coring a wellbore according to any one of claims 1 to 4, characterized in that: A wiring tray (9) is embedded in the upper connector (1), and a longitudinal through-hole is provided on the body of the wiring tray (9). At the same time, longitudinally connected binding posts are distributed and arranged, and pluggable line connection mechanisms are respectively installed at both ends of the binding posts.

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