Button electrode and drill collar for azimuth resistivity measurement while drilling

Abstract

The invention relates to a button electrode and a drill collar for azimuth resistivity measurement while drilling. The button electrode comprises a measuring electrode, an electrical unit, an insulator, a sealing element, an electrode cover plate, a plurality of conductive columns, a cabin body and an insulating pad, the plurality of conductive columns are arranged at the upper end of the measuring electrode; the measuring electrode, the insulator and the electrode cover plate are fixedly connected with the cabin body; the insulator is arranged between the measuring electrode and the electrode cover plate, the electrode cover plate tightly presses the insulator, and the insulator tightly presses the measuring electrode; sealing elements are arranged at the matching position of the insulator and the measuring electrode and the matching position of the insulator and the electrode cover plate; the electrical unit is arranged in a containing cavity formed by the measuring electrode and the cabin body, and the electrical unit is electrically connected with the measuring electrode; and the accommodating cavity is filled with a fluid medium. Under the conditions of underground high temperature, high pressure, high erosion and vibration, compared with an injection molding integrated button electrode structure in the prior art, the button electrode structure is higher in sealing performance, higher in insulating performance, more reliable in stability and longer in working time.

Description

Technical Field

[0001] The invention relates to a button electrode and a drill collar for azimuthal resistivity measurement while drilling. Background Art

[0002] With the continuous reduction of easily exploitable oil and gas resources, the development of oil and gas resources is becoming more and more difficult. In order to develop oil and gas resources more efficiently, it is necessary to obtain more reservoir geological information so that oil reservoirs can be found more accurately. The geological parameters of the reservoir generally include drill bit resistivity, azimuthal resistivity, gamma, porosity, etc. Among these parameters, azimuthal resistivity is directional and can accurately determine the direction of the oil layer. Geological engineers command the guidance tool to accurately drill into the oil and gas target layer based on the azimuthal resistivity and keep it in the reservoir without leaving the layer. Using azimuthal resistivity to detect the formation while drilling is conducive to accurate geological guidance during the drilling process, and plays an important role in improving oil and gas recovery rates and reducing operating costs and risks. Button electrodes are used to measure azimuthal resistivity and can also realize azimuthal resistivity imaging, providing data for accurate geological guidance. They are important structures of drilling instruments. Summary of the invention

[0003] In order to enrich the types of button electrodes in the prior art and improve the insulation performance of button electrodes, the present invention proposes a button electrode and a drill collar for azimuthal resistivity measurement while drilling. The technical solution proposed by the present invention is as follows:

[0004] In a first aspect, the present invention provides a button electrode for azimuthal resistivity measurement while drilling, which is applied to a drill collar and comprises: a measuring electrode, an electrical unit, a seal, an insulator, an electrode cover plate, a plurality of conductive columns, a cabin and an insulating pad;

[0005] The plurality of conductive posts are disposed at the upper end of the measuring electrode, and at least a portion of the conductive posts extends out of the outer surface of the measuring electrode;

[0006] The measuring electrode, the insulator and the electrode cover are all fixedly connected to the cabin, and the insulating pad is arranged between the measuring electrode and the cabin;

[0007] The insulator is arranged between the measuring electrode and the electrode cover plate, and the electrode cover plate presses the insulator, and the insulator presses the measuring electrode;

[0008] The sealing member is provided at the matching position between the insulator and the measuring electrode, and at the matching position between the insulator and the electrode cover plate;

[0009] The electrical unit is disposed in a receiving cavity formed by the measuring electrode and the cabin, and the electrical unit is electrically connected to the measuring electrode;

[0010] The accommodating cavity is filled with a fluid medium.

[0011] In some embodiments, the outer surface of the insulator is lower than the outer surface of the measuring electrode and the outer surface of the electrode cover plate.

[0012] In some embodiments, the outer surface of the measuring electrode and the outer surface of the electrode cover plate are consistent with the curvature of the outer surface of the cabin.

[0013] In some embodiments, a convex column is provided at the bottom end of the accommodating cavity, and the electrical unit is sleeved on the convex column.

[0014] In some embodiments, it further includes a wire plug;

[0015] The upper end of the measuring electrode is provided with a fluid channel for injecting the fluid medium, and the fluid channel is connected to the accommodating cavity;

[0016] The wire plug blocks one end of the fluid channel away from the accommodating cavity, and the wire plug is in contact with the protruding column.

[0017] In some embodiments, the measuring electrode is in the shape of a rectangular oval.

[0018] In some embodiments, it further includes a sealing pin; a stepped oblique hole is provided in the receiving groove of the cabin body for receiving the electrical unit, and the sealing pin is installed in the stepped oblique hole;

[0019] One end of the sealing pin is connected to the electrical unit, and the other end is used to connect to the circuit board of the cabin.

[0020] In some embodiments, further comprising a screw;

[0021] The electrode cover plate is provided with a plurality of countersunk holes, the screws are provided in the countersunk holes, and the electrode cover plate is fixed to the cabin or the drill collar by the screws.

[0022] In some embodiments, the nut of the screw is lower than the lowest point of the countersunk hole.

[0023] In some embodiments, the measuring electrode is threadably connected to the insulator, and a thread adhesive is disposed between the measuring electrode and the insulator.

[0024] In some embodiments, the conductive column and the measuring electrode are connected by threaded connection or interference fit.

[0025] In some embodiments, the insulator has a predetermined thickness.

[0026] In a second aspect, the present invention provides a drill collar, comprising the button electrode for azimuthal resistivity measurement while drilling as described in the first aspect;

[0027] The curvature of the outer surface of the measuring electrode is consistent with that of the outer surface of the drill collar.

[0028] In a third aspect, the present invention provides a method for measuring azimuthal resistivity while drilling, using the drill collar as described in the second aspect.

[0029] Based on the above technical solution, the beneficial effects of the present invention compared with the prior art are as follows:

[0030] The button electrode for azimuthal resistivity measurement while drilling provided by the present invention has a measuring electrode, an insulator and an electrode cover plate which are all fixedly connected to the cabin; the insulator is arranged between the measuring electrode and the electrode cover plate, and the electrode cover plate presses the insulator, and the insulator presses the measuring electrode; the pressure is transmitted layer by layer, the insulator and the measuring electrode are securely fixed, and the overall structure is compact, so that the button electrode structure is securely fixed on the cabin, ensuring the measurement of azimuthal resistivity while drilling. By filling the accommodating cavity with fluid medium, the high-pressure static sealing level is improved, and high-pressure mud is effectively prevented from invading the joint surface between the measuring electrode and the cabin. The mating position of the insulator and the measuring electrode, as well as the mating position of the insulator and the electrode cover plate are both provided with sealing members, which can prevent high-pressure mud from entering the joint surface between the insulator and the measuring electrode, and prevent high-pressure mud from entering the joint surface between the insulator and the electrode cover plate, thereby ensuring the high sealing of the button electrode, thereby ensuring the insulation performance, and improving the service life of the insulator. Compared with the injection-molded button electrode in the prior art, the button electrode structure of the present invention has stronger sealing, higher insulation, more reliable stability and longer working time under the conditions of high temperature, high pressure, high erosion and vibration underground.

[0031] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 is a three-dimensional structural diagram of a button electrode for azimuthal resistivity measurement while drilling provided by an embodiment of the present invention;

[0035] Figure 2 is a cross-sectional view of a button electrode for azimuthal resistivity measurement while drilling provided by an embodiment of the present invention;

[0036] Figure 3 is a top view of a button electrode for azimuthal resistivity measurement while drilling provided by an embodiment of the present invention;

[0037] Figure 4 is a partial structural diagram of a drill collar provided in an embodiment of the present invention;

[0038] Figure 5 is a cross-sectional view of a drill collar provided in an embodiment of the present invention;

[0039] In the figure: 1 is a measuring electrode, 2 is an electrical unit, 3 is a seal, 4 is an insulator, 5 is an electrode cover, 6 is a fluid channel, 7 is a receiving cavity, 8 is a conductive column, 9 is a cabin, 10 is an insulating pad, 11 is a screw plug, 12 is a countersunk hole, 13 is a screw, 14 is a sealing pin, 15 is a drill collar, 16 is a circuit board, and 17 is a protruding column. DETAILED DESCRIPTION

[0040] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0041] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0042] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are 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 understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] Horizontal wells have the characteristic of increasing the oil leakage area. At present, the number of horizontal wells developed is increasing year by year, and the horizontal section is also developing into a large horizontal section. The oil production of large displacement horizontal wells is 5 to 8 times higher than that of ordinary horizontal wells, but there are also many technical difficulties, especially the serious damage to the wellbore of the long horizontal section caused by drilling and even causing underground safety accidents. It is urgent to carry out the technical research of long horizontal section one-trip drilling. The inventor found in his work that the long horizontal section requires button electrodes to measure the azimuth resistivity to provide accurate geological guidance for the near-drill bit drilling instrument. The button electrode contacts the well wall and is eroded by high-pressure mud. The insulation of the button electrode in the prior art quickly decreases, resulting in measurement failure and forced drilling, which cannot meet the inventor's expectations. The button electrode that can work normally underground for a long time is an urgent problem to be solved.

[0045] The current research status of this type of button electrode structure is as follows:

[0046] In the invention patent (authorization announcement number: CN 10781634 B), the main electrode and the shielding electrode are filled with high-temperature and wear-resistant insulating materials such as glass fiber reinforced plastics or rubber. The glass fiber reinforced plastic insulation layer adopts high-temperature and high-pressure resistant epoxy resin, and the rubber insulation layer material adopts fluororubber. The VARTM technology of vacuuming and then injecting resin with an injection machine is adopted to wrap the glass fiber reinforced plastic insulation layer on the polytetrafluoroethylene coating. The rubber insulation layer is filled by uniformly pressing the rubber layer into shape through a special mold and attaching it to the gap between the shielding electrode and the main electrode.

[0047] The invention patent (application announcement number: CN 111810122 A) discloses a button electrode structure for a resistivity imaging logging instrument while drilling, wherein the measuring electrode, insulating layer, electrode support cover, and electrical pin are all injection molded into one piece through a special process.

[0048] The inventors found that the insulation structure of the above measuring electrodes adopts an injection-molded filling integrated structure. Common defects of the injection molding process are shrinkage holes and tiny cracks. In particular, the button electrode is not large in size, and the space required for injection molding is small. The injection molding cavity structure is irregular, which brings difficulties to the injection molding quality. The underground working conditions are harsh and complex, and the erosion is serious, which brings hidden dangers to the insulation. Because there are no sealing structural measures between injection molding materials such as rubber or fiberglass and measuring electrodes and drill collars, the bonding force between rubber or fiberglass and metal mainly depends on the bonding strength between rubber or fiberglass and metal. Once the bonding strength decreases under long-term high-pressure mud erosion, the sealing failure leads to insulation failure, which cannot meet the inventor's expectations. After further research and development, the inventors made the present invention.

[0049] Embodiment 1

[0050] The embodiment of the present invention provides a button electrode for azimuthal resistivity measurement while drilling, which is applied to a drill collar, referring to Figure 1 , Figure 2 and Figure 3 As shown, it includes: a measuring electrode 1, an electrical unit 2, a seal 3, an insulator 4, an electrode cover 5, a plurality of conductive columns 8, a cabin 9 and an insulating pad 10;

[0051] The plurality of conductive posts 8 are arranged at the upper end of the measuring electrode 1, and at least a part of the conductive posts 8 extends out of the outer surface of the measuring electrode 1. The measuring electrode 1 is a conductive metal and directly contacts the well wall. In order to improve the wear resistance of the measuring electrode 1, the present invention designs a wear-resistant conductive post 8 on the surface of the measuring electrode 1. The conductive post 8 uses a wear-resistant conductive material to improve the wear resistance and the conductivity, thereby establishing a wear-resistant conductive protection for the measuring electrode 1 and improving the conductivity and wear resistance of the measuring electrode 1.

[0052] Reference Figure 2 As shown, the measuring electrode 1, the insulator 4 and the electrode cover plate 5 are all fixedly connected to the cabin 9, and an insulating pad 10 is provided between the measuring electrode 1 and the cabin 9. The cabin 9 is a metal rectangular plate structure, and the insulating pad 10 realizes the insulation between the measuring electrode 1 and the cabin 9.

[0053] The insulator 4 is disposed between the measuring electrode 1 and the electrode cover plate 5, and the electrode cover plate 5 presses the insulator 4, and the insulator 4 presses the measuring electrode 1;

[0054] The seal 3 is provided at the matching position of the insulator 4 and the measuring electrode 1, and at the matching position of the insulator 4 and the electrode cover plate 5; the seal 3 provided at the matching position of the insulator 4 and the measuring electrode 1 is used to prevent high-pressure mud from entering the joint surface of the insulator 4 and the measuring electrode 1, the seal 3 provided at the matching position of the insulator 4 and the electrode cover plate 5 is used to prevent high-pressure mud from entering the joint surface of the insulator 4 and the electrode cover plate 5, and the seal 3 provided at the matching position of the insulator 4 and the cabin 9 is used to prevent high-pressure mud from entering the joint surface of the insulator 4 and the cabin 9. A composite sealing process is adopted between the measuring electrode 1, the electrode cover plate 5, the insulator 4, and the cabin 9 to ensure the high sealing of the button electrode, thereby ensuring the insulation performance. The seal 3 in the embodiment of the present invention is used together with a retaining ring and a high-temperature resistant rubber, and the assembly method is installed and used in accordance with the "Mechanical Manual".

[0055] The electrical unit 2 is disposed in the accommodating cavity 7 formed by the measuring electrode 1 and the cabin 9, and the electrical unit 2 is electrically connected to the measuring electrode 1;

[0056] The accommodating cavity 7 is filled with a fluid medium 2. The fluid medium 2 is filled with a flowing pressure-resistant medium to improve the high-pressure static sealing level of the button electrode and effectively prevent high-pressure mud from invading the joint surface. The liquid medium is a pressure-resistant flowing medium, such as hydraulic oil, silicone oil, etc.

[0057] In the embodiment of the present invention, the electrode cover plate 5 is a metal rectangular plate structure, and the outer surface of the electrode cover plate 5 is a cylindrical side surface with the same arc as the drill collar 15 to prevent the drill from tripping against the well wall or getting stuck.

[0058] The present invention relates to the technical field of oil and gas drilling, and specifically to a button electrode for measuring azimuthal resistivity while drilling, which is used to improve the service life and reliability of the button electrode and meet the need for long-term stable operation in the oil and gas well drilling environment. The measuring electrode 1, the insulator 4 and the electrode cover plate 5 are all fixedly connected to the cabin 9; the insulator 4 is arranged between the measuring electrode 1 and the electrode cover plate 5, and the electrode cover plate 5 presses the insulator 4, and the insulator 4 presses the measuring electrode 1; the pressure is transmitted layer by layer, and the insulator 4 and the measuring electrode 1 are securely fixed. The overall structure is compact, so that the button electrode structure is securely fixed on the cabin 9, ensuring the measurement of azimuthal resistivity while drilling. By filling the accommodating cavity 7 with a fluid medium, the high-pressure static sealing level is improved, and high-pressure mud is effectively prevented from invading the joint surface between the measuring electrode 1 and the cabin 9. The insulator 4 and the measuring electrode 1 match position, and the insulator 4 and the electrode cover plate 5 match position are both provided with seals 3, which can prevent high pressure mud from entering the joint surface between the insulator 4 and the measuring electrode 1, and prevent high pressure mud from entering the joint surface between the insulator 4 and the electrode cover plate 5, ensure the high sealing of the button electrode, thereby ensuring the insulation performance, and can improve the service life of the insulator 4. Compared with the injection-molded button electrode in the prior art, there is no sealing structure measure between the injection molding materials such as rubber or fiberglass and the measuring electrode and the drill collar. The bonding force between the injection molding materials such as rubber or fiberglass and the drill collar or electrode mainly depends on the bonding strength between rubber or fiberglass and metal. Once the bonding strength decreases under long-term high pressure mud erosion, the sealing failure leads to insulation failure. The button electrode provided by the present invention can still ensure the sealing of the button electrode structure under the conditions of high temperature, high pressure, high erosion and vibration in the well, with higher insulation, more reliable stability and longer working time.

[0059] The button electrode for azimuthal resistivity measurement while drilling provided by the embodiment of the present invention is easier to assemble than the prior art, and it is time-saving and labor-saving to disassemble and repair, and improves applicability and reliability. The insulator 4 is an independent part, and there is no injection-molded integral structure with the measuring electrode 1 and the cabin 9, which saves the mold, process equipment and process flow of the injection molding process, reduces the labor intensity of workers, and improves labor efficiency. Moreover, as an independent structure, the button electrode can be arranged on the drilling measurement instrument alone or in multiple buttons, which can realize the azimuthal resistivity imaging logging of the drilling instrument, and fine evaluation and geological guidance of reservoirs such as fracture identification, so as to provide guidance basis for the development of complex oil reservoirs and unconventional oil reservoirs. At present, the structure of the present invention has been applied to the field, and the button electrode is resistant to high temperature, high pressure and erosion, and the measurement data is accurate, the performance is stable and reliable, and the use effect is good. The present invention has realized azimuthal resistivity imaging, and the imaging logging image provided by the button electrode is used to improve the geological guidance and fine evaluation of complex high-point resistance reservoirs such as fractures, layers, low porosity and low permeability, and greatly improve the drilling rate and recovery rate.

[0060] In a specific embodiment, referring to Figure 3 As shown, the insulator 4 is shaped like a stepped cylinder that is small on the top and large on the bottom, and the insulator 4 has a stepped structure;

[0061] The electrode cover plate 5 is disposed on the stepped structure and presses the insulator 4 tightly.

[0062] Reference Figure 2 As shown, the step surface and the side of the step structure are both provided with sealing grooves, and the sealing member 3 is arranged in the sealing grooves. There is a sealing groove on the side of the large cylinder below, and the sealing member 3 is placed in the sealing groove. The sealing member 3 is used to prevent the high-pressure mud from entering from the joint surface of the insulator 4 and the measuring electrode 1.

[0063] In a specific embodiment, referring to Figure 1 and Figure 2 As shown, the outer surface of the insulator 4 is lower than the outer surface of the measuring electrode 1 and the outer surface of the electrode cover plate 5. The insulator 4 is a non-metallic non-conductive material and has no wear resistance compared with metal. The outer surface of the insulator 4 is lower than the outer surface of the measuring electrode 1 and the outer surface of the electrode cover plate 5, which can ensure that the insulator 4 will not be worn by the well wall, ensure the insulation performance of the insulator 4, and at the same time improve the service life of the insulator 4, thereby improving the service life of the entire button electrode.

[0064] In a specific embodiment, referring to Figure 1 As shown, the outer surface of the measuring electrode 1 and the outer surface of the electrode cover plate 5 are consistent with the curvature of the outer surface of the cabin 9. Since the measuring electrode 1 and the electrode cover plate 5 are in direct contact with the well wall during azimuthal resistivity measurement, the outer surfaces of the measuring electrode 1 and the electrode cover plate 5 are designed to be the same arc surface as the cabin 9, which is beneficial to protect the measuring electrode 1 from being bumped by the well wall. The shape of the measuring electrode 1 can be set according to the shape of the electrode cover plate 5 and the cabin 9. For example, the outer surface of the measuring electrode 1 can be a cylindrical side surface consistent with the outer diameter of the cabin 9 or the drill collar 15 to prevent bumping against the well wall and stuck drill, and at the same time, the distance between the measuring electrode 1 and the formation can be minimized.

[0065] In a specific embodiment, a boss 17 is provided at the bottom end of the accommodating cavity 7, and the electrical unit 2 is sleeved on the boss 17. The accommodating cavity 7 is a large groove formed by combining the measuring electrode 1 and the bottom groove of the cabin 9, and the electrical unit 2 is sleeved on the boss 17 to fix the electrical unit 2. The wire plug 11 is made of a metal conductive material, and the electrical unit 2 is sleeved on the boss 17, and is integrated into a ring-shaped electrical integrated block on the boss 17. The wire plug 11 fits with the boss 17, and can transmit the signal collected by the measuring electrode 1 to the electrical unit 2. All electrical appliances are integrated into the button electrode, which helps to fix the circuit assembly of the button electrode. The circuit assembly has the shortest routing, which greatly reduces the internal consumption of the circuit.

[0066] In a specific embodiment, referring to Figure 2 As shown, it also includes a plug 11. The upper end of the measuring electrode 1 is provided with a fluid channel 6 for injecting the fluid medium, and the fluid channel 6 is connected to the accommodating cavity 7. The plug 11 blocks the end of the fluid channel 6 away from the accommodating cavity 7, and the plug 11 is in contact with the protruding column 17. The fluid channel 6 is tightened with the plug 11 having sealing performance.

[0067] In a specific embodiment, referring to Figure 1 As shown, the measuring electrode 1 is in the shape of a rectangular ellipse. The shape of the measuring electrode 1 is designed to be in the shape of a rectangular ellipse, with semicircular transitions at both ends, which is helpful for assembling the sealing member 3 and improving the sealing reliability.

[0068] In a specific embodiment, referring to Figure 4 and Figure 5 As shown, it also includes a sealing pin 14; a stepped inclined hole (not shown in the figure) is provided in the receiving groove of the cabin 9 for receiving the electrical unit 2, and the sealing pin 14 is installed in the stepped inclined hole;

[0069] One end of the sealing pin 14 is connected to the electrical unit 2 , and the other end is used to connect to the circuit board 16 of the cabin 9 .

[0070] The electrical unit 2 is a mutual inductor that senses the current flowing into the button electrode. The sealing pin 14 is connected to the electrical unit 2 and the circuit board 16 in the cabin 9, respectively, and the azimuth resistivity signal collected by the electrical unit 2 is collected on the circuit board 16, and the azimuth resistivity signal is transmitted to the ground through the circuit board 16. The sealing pin 14 has an isolation effect, preventing the mud from flowing out of the button electrode into the tank of the cabin 9 and the mud in the tank of the cabin 9 from flowing into the inside of the button electrode, and has a dual protection effect. The sealing pin 14 uses a high-pressure sealing pin.

[0071] In a specific embodiment, referring to Figure 1 As shown, it also includes a screw 13;

[0072] The electrode cover plate 5 is provided with a plurality of countersunk holes 12 , and the screws 13 are provided in the countersunk holes 12 . The electrode cover plate 5 is fixed to the cabin 9 or the drill collar 15 by means of the screws 13 .

[0073] The screws 13 are used to fasten the electrode cover plate 5. The screws 13 tightened with a certain torque ensure that the electrode cover plate 5 presses the insulator 4, the electrode cover plate 5 clamps the insulator 4, and the insulator 4 clamps the measuring electrode 1, so that the pressure is transmitted layer by layer, the insulator 4 and the measuring electrode 1 are securely fixed, and the overall structure is compact and ingenious, so that the button electrode structure is securely fixed on the cabin 9, ensuring the safety and sealing of the button electrode structure. The number of the countersunk holes 12 can be set according to actual needs, and the present invention does not make specific limitations. Figure 1 As shown, the electrode cover plate 5 is provided with seven countersunk holes 12, and the screws 13 are arranged in the countersunk holes 12 to be fixed together with the chamber 9 or the drill collar 15. The screws 13 in the present invention are hexagon socket head screws 13, which are easy to disassemble.

[0074] In a specific embodiment, the nut of the screw 13 is lower than the lowest point of the countersunk hole 12. The nut of the screw 13 is lower than the lowest point of the countersunk hole 12, which can solve the problem of the screw 13 being loose or difficult to remove caused by the screw 13 hitting the well wall, and ensure that the nut is not worn.

[0075] In a specific embodiment, the measuring electrode 1 is threadedly connected to the insulator 4, and a thread adhesive is provided between the measuring electrode 1 and the insulator 4. An external thread is provided below the measuring electrode 1, and an internal thread is provided at a corresponding position of the insulator 4. The measuring electrode 1 is connected to the insulator 4 to prevent the thread from loosening due to vibration. The thread adhesive is applied before the connection to further improve the sealing between the measuring electrode 1 and the insulator 4.

[0076] In a specific embodiment, the conductive column 8 and the measuring electrode 1 are connected by threaded connection or interference fit.

[0077] In a specific embodiment, the insulator 4 has a preset thickness. The insulator 4 is a prefabricated part, and based on the design principle of the button electrode, the thickness of the insulator 4 can be set according to actual needs to ensure the insulation performance of the insulator 4.

[0078] The button electrode of the present invention has an azimuth characteristic and must be used in conjunction with a sensor for measuring azimuth, such as an accelerometer, which is also mounted on the cabin 9. The azimuth is determined based on the data signal of the accelerometer, and the azimuth resistivity is determined based on the current signal obtained by the button electrode at the azimuth.

[0079] The material of the insulator 4 in the embodiment of the present invention is selected from special polymer solid insulating materials for aviation, such as PTFE and polyimide. PTFE and polyimide materials have good electrical insulation; mechanical properties, rigidity and toughness, especially outstanding fatigue resistance under alternating stress; corrosion resistance, stable performance under acidic and alkaline conditions; small shrinkage rate, and very stable size.

[0080] Embodiment 2

[0081] Based on the same inventive concept, the embodiment of the present invention further provides a drill collar 15, referring to Figure 4 and Figure 5 As shown, it includes a button electrode for azimuthal resistivity measurement while drilling as described in any of the above embodiments, and the outer surface of the measuring electrode 1 has the same curvature as the outer surface of the drill collar 15.

[0082] The button electrode is arranged on the drill collar 15, and the button electrode on the drill collar 15 is used to realize the azimuthal resistivity measurement while drilling to form an imaging logging image, thereby improving the geological guidance and fine evaluation of complex high-point resistance reservoirs such as fractures, layers, low porosity, and low permeability, and greatly improving the drilling rate and recovery rate.

[0083] Embodiment 3

[0084] The embodiment of the present invention provides a method for measuring azimuthal resistivity while drilling, using the drill collar 15 as described in the above embodiment.

[0085] The drill collar 15 provided in the above embodiment can be used to measure the azimuthal resistivity while drilling. The specific measurement process can refer to the specific description in the prior art, which will not be repeated here.

[0086] In this document, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. The orientation or position relationship indicated by the terms "upper", "lower", etc. is based on the orientation or position relationship shown in the accompanying drawings, and 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 operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0087] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. The present invention is not limited to any single aspect, any single embodiment, or any combination and / or permutation of these aspects and / or embodiments. Each aspect and / or embodiment of the present invention can be used alone, or in combination with one or more other aspects and / or other embodiments.

[0088] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A button electrode for azimuthal resistivity measurement while drilling, applied to a drill collar, characterized in that: include: Measuring electrode (1), electrical unit (2), sealing member (3), insulator (4), electrode cover plate (5), multiple conductive columns (8), cabin (9) and insulating pad (10); The plurality of conductive columns (8) are arranged at the upper end of the measuring electrode (1), and at least a portion of the conductive columns (8) protrudes from the outer surface of the measuring electrode (1); The measuring electrode (1), the insulator (4) and the electrode cover plate (5) are all fixedly connected to the cabin (9), and the insulating pad (10) is provided between the measuring electrode (1) and the cabin (9); The insulator (4) is arranged between the measuring electrode (1) and the electrode cover plate (5), and the electrode cover plate (5) presses the insulator (4), and the insulator (4) presses the measuring electrode (1); The sealing member (3) is provided at the matching position between the insulator (4) and the measuring electrode (1), and at the matching position between the insulator (4) and the electrode cover plate (5); The electrical unit (2) is arranged in a receiving cavity (7) formed by the measuring electrode (1) and the cabin (9), and the electrical unit (2) is electrically connected to the measuring electrode (1); The accommodating cavity (7) is filled with a fluid medium.

2. The button electrode for azimuthal resistivity measurement while drilling according to claim 1, characterized in that: The outer surface of the insulator (4) is lower than the outer surface of the measuring electrode (1) and the outer surface of the electrode cover plate (5).

3. The button electrode for azimuthal resistivity measurement while drilling according to claim 1, characterized in that: The outer surface of the measuring electrode (1) and the outer surface of the electrode cover plate (5) are both consistent with the curvature of the outer surface of the cabin (9).

4. The button electrode for azimuthal resistivity measurement while drilling according to claim 1, characterized in that: A convex column (17) is provided at the bottom end of the accommodating cavity (7), and the electrical unit (2) is sleeved on the convex column (17).

5. The button electrode for azimuthal resistivity measurement while drilling according to claim 4, characterized in that: Also includes a wire plug (11); The upper end of the measuring electrode (1) is provided with a fluid channel (6) for injecting the fluid medium, and the fluid channel (6) is connected to the accommodating cavity (7); The wire plug (11) blocks one end of the fluid channel (6) away from the accommodating chamber (7), and the wire plug (11) is in contact with the protruding column (17).

6. The button electrode for azimuthal resistivity measurement while drilling according to claim 1, characterized in that: The measuring electrode (1) is in the shape of a rectangular ellipse.

7. The button electrode for azimuthal resistivity measurement while drilling according to claim 1, characterized in that: It also includes a sealing pin (14); a stepped inclined hole is provided in the receiving groove of the cabin (9) receiving the electrical unit (2), and the sealing pin (14) is installed in the stepped inclined hole; One end of the sealing pin (14) is connected to the electrical unit (2), and the other end is used to connect to the circuit board (16) of the cabin (9).

8. The button electrode for azimuthal resistivity measurement while drilling according to claim 1, characterized in that: Also includes a screw (13); The electrode cover plate (5) is provided with a plurality of countersunk holes (12), the screws (13) are arranged in the countersunk holes (12), and the electrode cover plate (5) is fixed to the cabin (9) or the drill collar via the screws (13).

9. The button electrode for azimuthal resistivity measurement while drilling according to claim 8, characterized in that: The nut of the screw (13) is lower than the lowest point of the countersunk hole (12).

10. The button electrode for azimuthal resistivity measurement while drilling according to claim 1, characterized in that: The measuring electrode (1) is threadably connected to the insulator (4), and a thread adhesive is provided between the measuring electrode (1) and the insulator (4).

11. The button electrode for azimuthal resistivity measurement while drilling according to claim 1, characterized in that: The conductive column (8) and the measuring electrode (1) are connected by threaded connection or interference fit.

12. The button electrode for azimuthal resistivity measurement while drilling according to claim 1, characterized in that: The insulator (4) has a preset thickness.

13. A drill collar, characterized in that: A button electrode for azimuthal resistivity measurement while drilling as claimed in any one of claims 1 to 12; The curvature of the outer surface of the measuring electrode (1) is consistent with that of the outer surface of the drill collar.

14. A method for measuring azimuthal resistivity while drilling, characterized in that: Use of a drill collar as claimed in claim 13.

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