Split resistivity logging button electrode, preparation method and instrument

Abstract

The present invention discloses a split resistivity logging button electrode, a preparation method and an instrument, comprising: an upper housing, an electrode block, a probe, an insulating component, a metal base and a bottom plate. The electrode block is hermetically connected to the upper opening of the upper housing. The electrode block includes a plurality of non-contact electrode components. A plurality of probe holes are formed on the metal base, and probe connection holes are formed on the electrode components. The top end of the probe passes through the probe holes and is connected to the electrode block through the probe connection holes. A wire welding hole is formed at the bottom end of the probe. The bottom plate is hermetically connected to the lower opening of the upper housing. The wire is led out through the wire welding hole and connected to the instrument through the wire passing hole of the bottom plate. The insulating component forms an insulating layer with a certain insulating thickness between each electrode component and between the electrode component and the metal base. Each electrode component is hermetically filled with the insulating layer. The upper housing is hermetically connected to the instrument. The present invention reduces the difficulty of process design and product implementation while not affecting the performance.

Description

Technical Field

[0001] The present invention relates to the technical field of instruments, and more specifically, to a split resistivity logging button electrode, a preparation method and an instrument thereof. Background Art

[0002] In oil and gas exploration, logging-while-drilling (LWD) instruments are used to measure the formation properties around the wellbore. Signals can be transmitted from the instrument into the formation, and some of the signals return to the instrument after passing through the formation. By analyzing the transmitted and received signals, formation properties can be obtained. Electrical signals are one of the commonly used signals, and the instrument transmits and receives the returned electrical signals. The components or assemblies responsible for transmitting and receiving are called electrodes. The electrodes are fixed on the instrument housing. The integrated electrode is called a button electrode because of its shape similar to a button. After the button electrode is installed on the instrument housing, one side contacts the liquid in the wellbore, and the other side is connected to the internal circuit of the instrument. The internal circuit controls each electrode to emit different current signals or receive the returned current from different measurement depths.

[0003] As a component of the LWD instrument, the electrode assembly can work continuously for hundreds of hours in a well several kilometers deep. The working environment temperature can reach above 175 degrees Celsius, and the pressure can reach above 140 megapascals, along with a large amount of intense vibration caused by drilling.

[0004] Currently, the commonly used processing method integrates the electrode part, insulating material and housing of the button electrode as a whole, and combines the three by means of high-pressure PEEK injection molding or high-temperature glass sintering. The manufacturing process is very complex, with a long process flow and a low success rate. For each design, a large amount of process design and debugging work is required, so the cost is expensive. At the same time, the biggest reliability problem faced by the button electrode is that the high-pressure liquid in the wellbore breaks through the bonding between the electrode and the insulating material and enters the instrument internal, which not only causes the failure of the electrode itself, but also causes the failure and scrapping of the internal circuit of the instrument, making the logging work unable to be completed, resulting in huge time and economic losses. Summary of the Invention

[0005] In view of the problems in the related art, the present invention provides a split resistivity logging button electrode, a preparation method and an instrument thereof, so as to overcome the above-mentioned technical problems existing in the prior related art.

[0006] To this end, the specific technical solution adopted by the present invention is as follows: A split resistivity logging button electrode, comprising: an upper housing, an electrode block, a probe, an insulating component, a metal base, and a bottom plate. The upper housing is a hollow structure with openings at both the top and bottom. The electrode block is located within the hollow structure of the upper housing. The top end of the electrode block is exposed outside the upper housing through the upper opening of the upper housing. The electrode block is sealingly connected to the upper opening of the upper housing. The electrode block includes a number of non-touching electrode components. A number of probe holes are provided on the metal base, and probe connection holes are provided corresponding to the probe holes on the electrode components. The top end of the probe passes through the probe hole and is connected to the electrode block through the probe connection hole. A wire hole is provided at the bottom end of the probe. The bottom plate is sealingly connected to the lower opening of the upper housing. A wire passing hole is provided on the bottom plate. The wire is led out through the wire hole and connected to the instrument through the wire passing hole. The insulating component is formed by injecting an insulating material inside the electrode block and between the electrode block and the metal base. The insulating component forms an insulating layer with a certain insulating thickness between each electrode component and between the electrode component and the metal base. Each electrode component is sealed and filled with the insulating layer. The upper housing is sealingly connected to the instrument.

[0007] Further, the upper surface of the upper housing is an arc-shaped structure, and the upper surfaces of the electrode block and the insulating component match the arc-shaped structure of the upper surface of the upper housing. The electrode component is an electrode ring, an electrode sheet, or an electrode needle.

[0008] Further, the insulating component is formed by injection molding of PEEK or rubber. A rubber sealing ring is sleeved on the probe to seal the probe hole.

[0009] Further, the electrode block is sealingly connected to the upper opening of the upper housing through a first sealing ring, and the bottom plate is sealingly connected to the lower opening of the upper housing through a second sealing ring.

[0010] Further, a gasket groove is provided on the upper surface of the bottom plate corresponding to the probe hole. A gasket is placed in the gasket groove. A gasket wire groove is provided on the gasket. A bottom plate wire groove is provided on the bottom plate. The gasket wire groove communicates with the bottom plate wire groove. The bottom plate wire groove communicates with the wire passing hole. The probe is connected to the bottom plate through the gasket. The wire is led out through the wire hole, then through the gasket wire groove and the bottom plate wire groove, and then passes through the wire passing hole to connect to the instrument.

[0011] Further, a step is provided on the upper housing. The upper housing presses the split resistivity logging button electrode onto the instrument through the step.

[0012] Further, the probe connection hole is a threaded hole.

[0013] Furthermore, a limiting block is connected to the side of the upper housing, and a force measuring unit is connected to the lower part of the upper housing. A compensation oil chamber is provided inside the instrument corresponding to the positions of the force measuring unit and the bottom of the split resistivity logging button electrode. The compensation oil chamber reaches pressure equilibrium with the liquid in the wellbore through a piston. The force measuring unit is connected to the upper housing through a push spring and a push piston. The split resistivity logging button electrode contacts the wellbore under the pushing action of the push piston, floats up and down when encountering irregularities in the wellbore wall, and at the same time, the thrust between it and the wellbore wall is controlled by the push spring. The force measuring unit measures and stores the thrust of the push spring.

[0014] The present application also provides a preparation method for a split resistivity logging button electrode, which is used to prepare any of the above-mentioned split resistivity logging button electrodes, and includes:

[0015] S1. According to the shape and size of the split resistivity logging button electrode to be prepared, the electrode components are processed to the same height.

[0016] S2. According to the position arrangement of several electrode components, several electrode components are fixed on the injection molding top plate, and the injection molding top plate is fixed on the upper part of the injection mold.

[0017] S3. The metal base is fixed to the lower part of the injection mold, and a certain insulation space is controlled between the metal base and the electrode components.

[0018] S4. The upper and lower parts of the injection mold are fastened and an insulating material is injected to form an insulating component.

[0019] S5. The metal base and the insulating component are taken out of the injection mold, the electrode components and the insulating component are cut and assembled according to the shape and size of the split resistivity logging button electrode to be prepared, and then the probe is assembled and wired, and finally the upper housing and the bottom plate are connected to obtain the split resistivity logging button electrode.

[0020] The present application also provides an instrument, including any of the above-mentioned split resistivity logging button electrodes or the split resistivity logging button electrodes prepared by the preparation method of the split resistivity logging button electrode as described above.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The present application proposes a split resistivity logging button electrode, which disassembles the traditional integral button electrode into several components and then seals and connects them. Compared with the integral design, the performance is not affected while the process design and product implementation difficulty are reduced.

[0023] 2. The split resistivity logging button electrode of the present application can be disassembled and maintained regularly, and parts such as sealing rings can be replaced, thereby improving the service life.

[0024] 3. The present application uses a sealing rubber ring for sealing, solving the problem of sealing failure between the electrode and the insulating material that is prone to occur in an integrated design under high temperature, high pressure, and high vibration environments.

[0025] 4. The present application proposes an electrode floating design. The electrode contacts the wellbore under the pushing action and floats up and down when encountering irregularities in the wellbore. At the same time, the thrust between the electrode and the wellbore is controlled by a spring, which can ensure sufficient contact and will not generate excessive friction to affect drilling and wear the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order 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 use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a three-dimensional structural schematic diagram of an instrument according to Embodiment 1 of the present invention;

[0028] Figure 2 It is a three-dimensional structural schematic diagram of a split resistivity logging button electrode from one angle according to Embodiment 1 of the present invention;

[0029] Figure 3 It is a three-dimensional structural schematic diagram of a split resistivity logging button electrode from another angle according to Embodiment 1 of the present invention;

[0030] Figure 4 It is an exploded view of a split resistivity logging button electrode according to Embodiment 1 of the present invention;

[0031] Figure 5 It is a three-dimensional structural schematic diagram of an electrode block in a split resistivity logging button electrode from one angle according to Embodiment 1 of the present invention;

[0032] Figure 6 It is a three-dimensional structural schematic diagram of an electrode block in a split resistivity logging button electrode from another angle according to Embodiment 1 of the present invention;

[0033] Figure 7 It is a three-dimensional structural schematic diagram of a probe in a split resistivity logging button electrode from one angle according to Embodiment 1 of the present invention;

[0034] Figure 8 It is a three-dimensional structural schematic diagram of a probe in a split resistivity logging button electrode from another angle according to Embodiment 1 of the present invention;

[0035] Figure 9It is a three-dimensional structure schematic diagram of a metal base of a split resistivity logging button electrode according to Embodiment 1 of the present invention from a certain angle;

[0036] Figure 10 It is a three-dimensional structure schematic diagram of a bottom plate of a split resistivity logging button electrode according to Embodiment 1 of the present invention from a certain angle;

[0037] Figure 11 It is a three-dimensional structure schematic diagram of the bottom plate of a split resistivity logging button electrode according to Embodiment 1 of the present invention from another angle;

[0038] Figure 12 It is a three-dimensional structure schematic diagram of an insulating component of a split resistivity logging button electrode according to Embodiment 1 of the present invention from a certain angle;

[0039] Figure 13 It is a three-dimensional structure schematic diagram of the insulating component of a split resistivity logging button electrode according to Embodiment 1 of the present invention from another angle;

[0040] Figure 14 It is a partial sectional structure schematic diagram of an instrument according to Embodiment 1 of the present invention;

[0041] Figure 15 It is a three-dimensional structure schematic diagram of an injection molding top plate used in the preparation method of a split resistivity logging button electrode according to Embodiment 2 of the present invention from a certain angle;

[0042] Figure 16 It is a position structure schematic diagram of a metal base and an injection molding top plate during the injection molding process in the preparation method of a split resistivity logging button electrode according to Embodiment 2 of the present invention;

[0043] Figure 17 It is a sectional structure schematic diagram of a mold, a metal base and an electrode assembly during injection molding in the preparation method of a split resistivity logging button electrode according to Embodiment 2 of the present invention. Detailed implementation manners

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Embodiment 1

[0045] Such as Figure 1-14As shown in the figure, a split resistivity logging button electrode. The split resistivity logging button electrode B includes: an upper housing 1, an electrode block 2, a probe 3, an insulating component 7, a metal base 4, and a bottom plate 5. In this embodiment, the upper surface of the upper housing 1 is an arc-shaped structure that is high in the middle and low on both sides. The upper surfaces of the electrode block 2 and the insulating component 7 match the arc-shaped structure of the upper surface of the upper housing 1, as Figure 2-4 shown, the upper housing 1 is a hollow structure with openings at both the top and bottom. The electrode block 2 is located inside the hollow structure of the upper housing 1. The top end of the electrode block 2 is exposed outside the upper housing 1 through the upper opening of the upper housing 1. The electrode block 2 is sealingly connected to the upper opening of the upper housing 1 through a first sealing ring 8. The electrode block 2 includes a number of non-touching electrode components 21. Since sufficient insulation thickness needs to be ensured between adjacent electrode components 21, the electrode components 21 do not touch each other. In this embodiment, the distance between adjacent electrode components 21 is 2 millimeters.

[0046] As Figure 5 and 6 shown, in this embodiment, the electrode component 21 uses an electrode ring. There are insulating gaps between the four electrode rings, and the insulating gaps are filled with the insulating component 7, as Figure 9 shown, a number of probe holes 41 are opened on the metal base 4. The electrode component 21 is provided with probe connection holes 22 corresponding to the probe holes 41. The top end of the probe 3 passes through the probe holes 41 and is connected to the electrode block 2 through the probe connection holes 22. The probe connection holes 22 are threaded holes, and the probe connection holes 22 are threadedly connected to the probe 3. There are also insulating gaps between the four electrode rings and the metal base 4, and the insulating gaps are also filled with the insulating component 7. A rubber sealing ring 32 is sleeved on the probe 3 to seal with the probe holes 41, as Figure 7 and 8 shown, a wire welding hole 31 is opened at the bottom end of the probe 3. The bottom plate 5 is sealingly connected to the lower opening of the upper housing 1 through a second sealing ring 9.

[0047] As Figure 10 and 11 shown, a wire passing hole 53 is opened on the bottom plate 5. After the wire is led out from the wire welding hole 31, it is connected to the instrument A through the wire passing hole 53. The insulating component 7 is formed by injecting insulating material inside the electrode block 2 and between the electrode block 2 and the metal base 4. In this embodiment, the insulating component 7 is formed by rubber injection molding, as Figure 12 and 13 shown, the insulating component 7 forms an insulating layer with a certain insulating thickness between each electrode component 21 and between the electrode component 21 and the metal base 4. Each electrode component 21 is sealed and filled with the insulating layer. The upper housing 1 is sealingly connected to the instrument A, and the upper housing 1 can be fixed to the instrument A by means of threaded connection or other fixing methods.

[0048] It should be noted that a gasket groove 52 is provided on the upper surface of the bottom plate 5 corresponding to the probe holes 41. A gasket 6 is placed in the gasket groove 52. A gasket wire groove 61 is provided on the gasket 6. A bottom plate wire groove 51 is provided on the bottom plate 5. The gasket wire groove 61 communicates with the bottom plate wire groove 51. The bottom plate wire groove 51 communicates with a wire passing hole 53. The probe 3 is connected to the bottom plate 5 through the gasket 6. After the wire is led out from the wire bonding hole 31, it is led through the gasket wire groove 61 and the bottom plate wire groove 51, and then passes through the wire passing hole 53 to connect to the instrument A.

[0049] In addition, a step is provided on the upper housing 1. The upper housing 1 presses the split resistivity logging button electrode B on the instrument A through the step.

[0050] It should also be noted that a shock-absorbing design such as rubber can be added between the bottom plate 5 and the instrument A, and a pressure-bearing and sealing wire-passing design can also be added in the wire-passing hole of the outer shell of the instrument A to further ensure the safety of the instrument.

[0051] Since the instrument A is located in the wellbore and the wellbore is filled with liquid, the measurement signal will be affected by the liquid in the well. To improve the measurement quality, the electrode surface should contact the wellbore wall as much as possible. However, the instrument A is involved in drilling and rotates at high speed and rubs against the wellbore wall during use. If the outer diameter of the instrument A contacts the wellbore wall, it will hinder the normal operation of drilling. Moreover, the inner wall of the wellbore is irregular with a large number of unevennesses. Therefore, the present invention proposes an electrode floating design. Since the liquid pressure in the wellbore exceeds 100 MPa, in order to achieve the floating design, a compensation oil chamber must be provided at the bottom of the electrode. The oil chamber reaches pressure balance with the liquid in the wellbore through a piston. The volume of the liquid in the oil chamber changes with temperature and pressure, and the piston can move up and down to adapt to the volume change. A push spring and a push piston must be provided below the electrode, and a limit block is provided above. The electrode contacts the wellbore wall under the push action and floats up and down when encountering irregularities in the wellbore wall. At the same time, the thrust between the electrode and the wellbore wall is controlled by the spring, which can ensure sufficient contact and will not generate excessive friction to affect drilling and wear the electrode. Specifically, as Figure 14 shown, a limit block 12 is connected to the side of the upper housing 1, and a force measuring unit 11 is connected to the lower part of the upper housing 1. A compensation oil chamber A1 is provided inside the instrument A corresponding to the position of the force measuring unit 11 and the bottom of the split resistivity logging button electrode B. The compensation oil chamber A1 reaches pressure balance with the liquid in the wellbore through a piston. The force measuring unit 11 is connected to the upper housing 1 through a push spring and a push piston. The split resistivity logging button electrode B contacts the wellbore wall under the push action of the push piston and floats up and down when encountering irregularities in the wellbore wall. At the same time, the thrust between the electrode and the wellbore wall is controlled by the push spring, and the force measuring unit measures and stores the thrust of the push spring. Embodiment 2

[0052] As Figure 15-17 shown, a preparation method for a split resistivity logging button electrode is used to prepare the split resistivity logging button electrode of Embodiment 1, including:

[0053] S1. According to the shape and size of the split resistivity logging button electrode B with an arc structure prepared according to Embodiment 1, first process the four electrode rings uniformly to the height in the middle of the arc structure.

[0054] S2. According to the position arrangement of the four electrode rings, fix the four electrode rings on the injection molding top plate 10, and fix the injection molding top plate 10 on the upper part of the injection mold.

[0055] S3. Fix the metal base 4 on the lower part of the injection mold, and control a certain insulation space between the metal base 4 and the four electrode rings.

[0056] S4. Fasten the upper and lower parts of the injection mold and inject an insulating material to form the insulating component 7.

[0057] S5. Take out the metal base 4 and the insulating component 7 from the injection mold, cut and assemble the electrode rings and the insulating component 7 according to the shape and size of the split resistivity logging button electrode B to be prepared, then assemble the probe 3 and connect the wires, and then connect the upper shell 1 and the bottom plate 5 to obtain the split resistivity logging button electrode B. Embodiment 3

[0058] An instrument includes a split resistivity logging button electrode as in Embodiment 1 or a split resistivity logging button electrode prepared by the preparation method of the split resistivity logging button electrode as in Embodiment 2.

[0059] 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 split resistivity logging button electrode, characterized in that, The split resistivity logging button electrode (B) includes: an upper housing (1), an electrode block (2), a probe (3), an insulating assembly (7), a metal base (4), and a bottom plate (5). The upper housing (1) is a hollow structure with openings at both the top and bottom. The electrode block (2) is located inside the hollow structure of the upper housing (1). The top end of the electrode block (2) is exposed outside the upper housing (1) through the upper opening of the upper housing (1). The electrode block (2) is hermetically connected to the upper opening of the upper housing (1). The electrode block (2) includes a number of non-touching electrode assemblies (21). A number of probe holes (41) are formed on the metal base (4). Probe connection holes (22) are formed on the electrode assemblies (21) corresponding to the probe holes (41). The top end of the probe (3) passes through the probe holes (41) and is connected to the electrode block (2) through the probe connection holes (22). A wire hole (31) is formed at the bottom end of the probe (3). The bottom plate (5) is hermetically connected to the lower opening of the upper housing (1). A wire passing hole (53) is formed on the bottom plate (5). The wire is led out from the wire hole (31) and connected to the instrument (A) through the wire passing hole (53). The insulating assembly (7) is formed by injecting insulating material inside the electrode block (2) and between the electrode block (2) and the metal base (4). The insulating assembly (7) forms an insulating layer with a certain insulating thickness between each electrode assembly (21) and between the electrode assembly (21) and the metal base (4). Each electrode assembly (21) is hermetically filled with the insulating layer. The upper housing (1) is hermetically connected to the instrument (A). A limit block (12) is connected to the side of the upper housing (1). A force measuring unit (11) is connected to the lower part of the upper housing (1). A compensation oil chamber (A1) is provided inside the instrument (A) corresponding to the position of the force measuring unit (11) and the bottom of the split resistivity logging button electrode (B). The compensation oil chamber (A1) reaches pressure balance with the liquid in the wellbore through a piston. The force measuring unit (11) is connected to the upper housing (1) through a push spring and a push piston. The split resistivity logging button electrode (B) contacts the wellbore under the pushing action of the push piston. When encountering irregularities in the wellbore, it floats up and down. At the same time, the thrust between it and the wellbore is controlled by the push spring. The force measuring unit measures and stores the thrust of the push spring.

2. The split resistivity logging button electrode according to claim 1, characterized in that, The upper surface of the upper housing (1) is an arc structure. The upper surfaces of the electrode block (2) and the insulating assembly (7) match the arc structure of the upper surface of the upper housing (1). The electrode assemblies (21) are electrode rings, electrode plates, or electrode needles.

3. A split resistivity logging button electrode according to claim 1 or 2, characterized in that, The insulating assembly (7) is formed by injecting PEEK or rubber. A rubber sealing ring (32) is sleeved on the probe (3) to seal with the probe hole (41).

4. A split resistivity logging button electrode according to claim 1 or 2, characterized in that, The electrode block (2) is hermetically connected to the upper opening of the upper housing (1) through a first sealing ring (8). The bottom plate (5) is hermetically connected to the lower opening of the upper housing (1) through a second sealing ring (9).

5. A split resistivity logging button electrode according to claim 1 or 2, characterized in that, On the upper surface of the bottom plate (5), a gasket groove (52) is provided corresponding to the probe hole (41). A gasket (6) is placed inside the gasket groove (52). A gasket wire groove (61) is provided on the gasket (6). A bottom plate wire groove (51) is provided on the bottom plate (5). The gasket wire groove (61) communicates with the bottom plate wire groove (51). The bottom plate wire groove (51) communicates with a wire passing hole (53). The probe (3) is connected to the bottom plate (5) through the gasket (6). After the wire is led out from the wire bonding hole (31), it is led through the gasket wire groove (61) and the bottom plate wire groove (51), and then passes through the wire passing hole (53) to connect to the instrument (A).

6. A split resistivity logging button electrode according to claim 1 or 2, characterized in that, The upper shell (1) is provided with a step. The upper shell (1) presses the split resistivity logging button electrode (B) on the instrument (A) through the step.

7. A split resistivity logging button electrode according to claim 1 or 2, characterized in that, The probe connection hole (22) is a threaded hole.

8. A preparation method of a split resistivity logging button electrode for preparing the split resistivity logging button electrode according to any one of claims 1-7 above, characterized in that, Comprising: S1. According to the shape and size of the split resistivity logging button electrode (B) to be prepared, the electrode assemblies (21) are processed to the same height respectively; S2. According to the positional arrangement of a plurality of electrode assemblies (21), the plurality of electrode assemblies (21) are fixed on the injection molding top plate (10), and the injection molding top plate (10) is fixed on the upper part of the injection mold; S3. The metal base (4) is fixed on the lower part of the injection mold, and a certain insulation space is controlled between the metal base (4) and the electrode assemblies (21); S4. The upper and lower parts of the injection mold are fastened and an insulating material is injected to form an insulating assembly (7); S5. The metal base (4) and the insulating assembly (7) are taken out of the injection mold. According to the shape and size of the split resistivity logging button electrode (B) to be prepared, the electrode assemblies (21) and the insulating assembly (7) are cut and assembled. Then the probe (3) is assembled and wired, and then the upper shell (1) and the bottom plate (5) are connected to obtain the split resistivity logging button electrode (B).

9. An instrument, characterized in that, Comprising the split resistivity logging button electrode as described in any one of claims 1-7 or the split resistivity logging button electrode prepared by the preparation method of the split resistivity logging button electrode as described in claim 8.

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