A logging while drilling device

Abstract

The present invention belongs to the technical field of well logging instruments, and specifically relates to a logging-while-drilling device. The logging-while-drilling device comprises: a housing, which is detachably mounted on a downhole tool and contains at least one antenna; multiple magnetic rods, each uniformly arranged circumferentially within the housing, with the central axes of the magnetic rods parallel to the central axis of the housing; and a measurement circuit, which is sealed within the downhole tool and connected to the antenna. The present invention reduces the difficulty of antenna operation and maintenance, facilitating installation.

Description

Technical Field

[0001] The present invention belongs to the technical field of well logging instruments, and in particular relates to a logging while drilling device. Background Art

[0002] With the improvement of oilfield exploration and development, the application of while-drilling electromagnetic wave resistivity instruments in formation evaluation and geological guidance is becoming more and more extensive.

[0003] The amplitude and phase resistivity used in formation evaluation are derived by converting the amplitude ratio and phase difference of electromagnetic wave signals from two receiving antennas. Existing LWD electromagnetic wave resistivity instruments typically use multiple transmitters and two receivers for formation resistivity measurement. For example, Schlumberger's MCR tool uses two transmitters and two receivers, while Halliburton's EWR-phase 4 tool uses four transmitters and two receivers. Both the transmitting and receiving antennas are embedded in the drill collar.

[0004] In practice, embedding the antenna into the drill collar improves instrument reliability. However, for field engineers, this leads to high maintenance costs after the instrument is lowered into the well. If the antenna breaks or the sealant is damaged, the instrument must be sent to the manufacturing facility for removal and recalibration, increasing operational costs. Therefore, improvements in antenna design and installation methods are urgently needed. Summary of the Invention

[0005] In response to the above-mentioned technical problems, the present invention aims to provide a logging while drilling device, which can reduce the difficulty of antenna operation and maintenance and facilitate installation.

[0006] According to the present invention, there is provided a logging while drilling device, comprising:

[0007] A housing, wherein the housing is configured in a semicircular shape, and two housings are interlocked so as to be detachably mounted on the downhole tool;

[0008] An antenna is provided in the housing, the antenna comprising an axial antenna and a tilted antenna staggered in the housing, the axial antenna and the tilted antenna being respectively provided with a first circuit and a second circuit adapted thereto, the axial antenna being adapted to the first circuit, the tilted antenna being adapted to the second circuit, the antenna and its adapted circuit being encapsulated together in the housing, requiring no debugging, being connectable and usable immediately, and being easy to use; the axial antenna being used for conventional electromagnetic wave resistivity measurement, and the tilted antenna being used for azimuthal electromagnetic wave resistivity measurement;

[0009] A pin and a socket that adapt to each other are provided between the contact surfaces of the two shells. When the pin and the socket are plugged into each other, the two shells are fixedly connected on the one hand, and the partial axial antenna and the partial tilted antenna in the two shells are electrically connected on the other hand, forming a complete axial antenna and a complete tilted antenna;

[0010] A plurality of magnetic bars are evenly arranged along the circumferential direction in the shell, and the central axes of the magnetic bars are parallel to the central axis of the shell;

[0011] A measuring circuit is sealed and disposed in the downhole tool and is connected to the axial antenna and the tilted antenna in a detachable manner.

[0012] In a preferred embodiment, a detector installation groove is provided on the downhole tool, and the housing is provided in the detector installation groove.

[0013] In a preferred embodiment, a circuit installation groove is provided on the downhole tool, and the measurement circuit is sealed in the circuit installation groove.

[0014] In a preferred embodiment, a connecting wire is provided inside the downhole tool between the detector installation slot and the circuit installation slot, one end of the connecting wire is connected to the measurement circuit, and the other end is connected to the antenna.

[0015] In a preferred embodiment, a protective cover is provided on the outside of the housing.

[0016] In a preferred embodiment, a plurality of gaps are evenly arranged on the protective cover along the circumference.

[0017] In a preferred embodiment, both ends of the antenna extend from axial ends of the housing.

[0018] In a preferred embodiment, the axial antenna is arranged in a ring shape within the housing, and a central axis of the ring formed by the axial antenna is parallel to a central axis of the housing.

[0019] In a preferred embodiment, the tilted antenna is arranged in a ring shape within the housing, and a central axis of the ring formed by the tilted antenna is inclined to a central axis of the housing.

[0020] In a preferred embodiment, the connecting line is connected to the antenna in a detachable manner.

[0021] Compared with the prior art, the advantages of this application are as follows.

[0022] The present invention arranges the antenna in a cylindrical shell, and the shell is installed on the downhole tool in a conveniently disassembled manner. Once a problem occurs with the antenna or the sealant, the shell can be disassembled and replaced nearby, which greatly reduces the operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described below with reference to the accompanying drawings.

[0024] Figure 1 A schematic diagram showing an embodiment of a housing and an antenna therein according to the present invention;

[0025] Figure 2 A schematic diagram showing an embodiment in which the housing is combined into a tubular shape according to the present invention;

[0026] Figure 3 It shows a schematic diagram of the installation structure of the logging while drilling device according to the present invention;

[0027] Figure 4 The figure shows a flow chart of installing the logging while drilling device according to the present invention.

[0028] In the figure: 100, logging while drilling device; 101, axial antenna; 102, tilted antenna; 103, magnetic rod; 104, first circuit; 105, second circuit; 106, housing; 107, first pin; 108, first jack; 109, second pin; 110, second jack; 111, third pin; 112, fourth pin; 113, fifth pin; 114, sixth pin; 115, partition surface; 301, protective cover; 302, gap; 303, non-magnetic drill collar; 304, detector mounting slot; 305, third jack; 306, fourth jack; 307, fifth jack; 308, sixth jack; 309, circuit mounting slot; 310, measuring circuit.

[0029] In this application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn to scale. DETAILED DESCRIPTION

[0030] The present invention will be described below with reference to the accompanying drawings.

[0031] Figures 1 to 3 FIG. 1 shows the structure of a logging while drilling device 100 according to the present invention. Figures 1 to 3 As shown, the logging while drilling device 100 includes a housing 106, a magnetic rod 103, and a measurement circuit 310. The housing 106 can be detachably mounted on a downhole tool. In this embodiment, the downhole tool is a non-magnetic drill collar 303, and the housing 106 can be detachably mounted on the non-magnetic drill collar 303.

[0032] like Figure 1 and Figure 2 As shown, the housing 106 of this embodiment is configured as two semicircular structures, and the two semicircular housings 106 are buckled together to form a circular tube shape, thereby being sleeved on the non-magnetic drill collar 303. Figure 1 The structure in which two semicircular shells 106 are separated from each other is shown. Figure 2The structure is shown in which two semicircular shells 106 are buckled together to form a circular tube.

[0033] In this embodiment, housing 106 is made of epoxy resin, capable of withstanding high temperatures and high pressures. At least one antenna is disposed within housing 106 and connected to measurement circuit 310 to implement measurement-while-drilling (MWD) functionality. The basic operating principles of the antenna and measurement circuit 310 are readily understood and will not be further elaborated here.

[0034] Specifically, if Figure 1 and Figure 2 As shown, two antennas are disposed within the housing 106: an axial antenna 101 and a tilted antenna 102. A first circuit 104 and a second circuit 105 are provided on the axial antenna 101 and the tilted antenna 102, respectively, to match them. The axial antenna 101 can be used to perform conventional electromagnetic wave resistivity measurements, while the tilted antenna 102 can be used to perform azimuthal electromagnetic wave resistivity measurements, providing multi-purpose functionality. Both the axial antenna 101 and the tilted antenna 102 are configured in a circular ring shape and fixed within the housing 106. The central axis of the ring formed by the axial antenna 101 is parallel to the central axis of the housing 106. Furthermore, in this embodiment, the central axis of the ring formed by the axial antenna 101 coincides with the central axis of the housing 106. The central axis of the ring formed by the tilted antenna 102 is inclined relative to the central axis of the housing 106. Furthermore, in this embodiment, the central axis of the ring formed by the tilted antenna 102 intersects with the central axis of the housing 106.

[0035] In this embodiment, the two housings 106 are fastened together to form a complete circular tube. The contact surface of the two housings 106 is a partition surface 115, and the plane on which the partition surface 115 lies passes through the central axis of the housings 106. Because the two housings 106 need to be separated, the axial antenna 101 and the tilted antenna 102 are each divided into two parts, respectively disposed within the two housings 106. When the two housings 106 are fastened together, that is, when the partition surfaces 115 of the two housings 106 contact each other, the two parts of the axial antenna 101 and the tilted antenna 102 are connected to each other, forming the complete axial antenna 101 and the tilted antenna 102, respectively.

[0036] That is, the axial antenna 101 is divided into two parts, disposed within two housings 106. Taking the axial antenna 101 within one of the housings 106 as an example, the housing 106 includes two partition surfaces 115. One end of the axial antenna 101 extends circumferentially from one of the partition surfaces 115 of the housing 106. The other end of the axial antenna 101 enters the interior of the housing 106, extending along the circumference of the housing 106 until it reaches the other partition surface 115 of the housing 106. It then extends radially along the housing 106 until it extends from the axial end of the housing 106. Furthermore, the portions of the axial antennas 101 extending from the partition surface 115 of the two housings 106 are detachably connected to each other, thereby forming a complete axial antenna 101. Specifically, a first pin 107 is provided on the axial antenna 101 extending from the partition surface 115 of one shell 106, and a first socket 108 is provided on the axial antenna 101 extending from the partition surface 115 of the other shell 106. When the two shells 106 are buckled together, the first pin 107 is inserted into the first socket 108, which can be electrically connected and withstand high-voltage sealing, thereby connecting the two parts of the axial antenna 101 to each other to form a complete axial antenna 101.

[0037] Similarly, the tilted antenna 102 is divided into two parts, each housed within two housings 106. Taking the tilted antenna 102 within one of the housings 106 as an example, the housing 106 includes two partition surfaces 115. One end of the tilted antenna 102 extends circumferentially from one of the partition surfaces 115 of the housing 106. The other end of the tilted antenna 102 enters the interior of the housing 106, extending along the circumference of the housing 106 at a certain angle until it reaches the other partition surface 115 of the housing 106. It then extends radially along the housing 106 until it protrudes from the axial end of the housing 106. Furthermore, the portions of the tilted antennas 102 extending from the partition surfaces 115 of the two housings 106 are detachably connected to each other, thereby forming a complete tilted antenna 102. Specifically, a second pin 109 is provided on the tilted antenna 102 extending from the partition surface 115 of one of the shells 106, and a second socket 110 is provided on the tilted antenna 102 extending from the partition surface 115 of the other shell 106. When the two shells 106 are buckled together, the second pin 109 is inserted into the second socket 110, which can be electrically connected and withstand high-voltage sealing, so that the two parts of the tilted antenna 102 are connected to each other to form a complete tilted antenna 102.

[0038] The two parts of the axial antenna 101 extending from the axial end of the housing 106 are respectively provided with a third pin 111 and a fourth pin 112. The two parts of the tilted antenna 102 extending from the axial end of the housing 106 are respectively provided with a fifth pin 113 and a sixth pin 114. Figure 2As shown, when the two housings 106 are buckled together, only the third pin 111 , the fourth pin 112 , the fifth pin 113 and the sixth pin 114 are exposed outside the housing 106 .

[0039] In a specific embodiment, the entire axial antenna 101 is a single wire with high conductivity and a small cross-sectional area. It is axially wound around the outer side of the magnetic rod 103, perpendicular to the housing 106. When AC current is applied, it generates a regular magnetic field signal and can also sense changes in the surrounding magnetic field and convert them into electric field signals. Therefore, the axial antenna 101 can function as both a transmitting antenna and a receiving antenna. The first circuit 104, composed of resistors and capacitors, adjusts the impedance of the axial antenna 101. One end is connected to the axial antenna 101, and the other end is connected to the fourth pin 112.

[0040] In one specific embodiment, the entire tilted antenna 102 is a single wire with high conductivity and a small cross-sectional area. It is wound around the outer side of the magnetic rod 103 at an oblique angle to the axis of the housing 106. It can sense changes in the surrounding magnetic field and convert them into electric field signals. Generally, the tilted antenna 102 functions as a receiving antenna. The second circuit 105, composed of resistors and capacitors, adjusts the impedance of the tilted antenna 102. One end is connected to the tilted antenna 102, and the other end is connected to the sixth pin 114.

[0041] Multiple magnetic bars 103 are evenly arranged along the circumference of the housing 106, with the central axes of the magnetic bars 103 parallel to the central axis of the housing 106. In a specific embodiment, the magnetic bars 103 are cylindrical in shape, with a length less than the length of the housing 106 and a diameter less than the wall thickness of the housing 106. The multiple magnetic bars 103 are evenly spaced around the circumference of the housing 106, thereby increasing the magnetic field strength near the housing 106.

[0042] like Figure 3 As shown, a detector mounting groove 304 is provided on the non-magnetic drill collar 303, and the housing 106 is provided in the detector mounting groove 304. Specifically, the detector mounting groove 304 is provided as an annular groove structure, which is adapted to the shape and size of the housing 106.

[0043] A circuit installation slot 309 is provided on the non-magnetic drill collar 303, and the measuring circuit 310 is sealed and disposed in the circuit installation slot 309. Specifically, the circuit installation slot 309 is provided as a rectangular parallelepiped structure, which can accommodate the measuring circuit 310.

[0044] A connecting wire is installed inside the non-magnetic drill collar 303 between the detector mounting slot 304 and the circuit mounting slot 309. One end of the connecting wire is connected to the measurement circuit 310, and the other end is connected to the antenna. Specifically, this embodiment provides four connecting wires, which are arranged along the axis of the non-magnetic drill collar 303. The ends of the four connecting wires near the detector mounting slot 304 are respectively provided with a third jack 305, a fourth jack 306, a fifth jack 307, and a sixth jack 308. The other ends of the four connecting wires extend into the circuit mounting slot 309 and are connected to the measurement circuit 310.

[0045] Through this arrangement, when the housing 106 is installed in the detector mounting slot 304, the exposed third pin 111, fourth pin 112, fifth pin 113, and sixth pin 114 can be plugged into the third jack 305, fourth jack 306, fifth jack 307, and sixth jack 308, respectively, enabling electrical connection and withstanding high-pressure sealing, thereby achieving the purpose of quickly connecting the antenna in the housing 106 to the measurement circuit 310. The measurement circuit 310 transmits an alternating current signal to the axial antenna 101 and also transmits the electromagnetic wave reception signal from the tilted antenna 102 to the measurement circuit 310 for signal acquisition. At the same time, this arrangement allows the measurement circuit 310 to be separated from the housing 106. The measurement circuit 310 can be sealed within the non-magnetic drill collar 303, while the housing 106 portion is connected to the exterior of the non-magnetic drill collar 303.

[0046] Furthermore, a protective cover 301 is provided on the outside of the shell 106. In this embodiment, the protective cover 301 is also composed of two semicircular parts to form a complete circular tube. After the shell 106 is set in the detector mounting groove 304, the protective cover 301 is then sleeved on the outside of the shell 106, thereby protecting the shell 106.

[0047] Furthermore, a plurality of slits 302 are evenly arranged along the circumference of the protective cover 301. The length direction of each slit 302 is parallel to the axis direction of the protective cover 301. The slits 302 can enhance the transmission intensity of the electromagnetic wave signal.

[0048] The present invention can perform conventional electromagnetic wave resistivity measurement using the axial antenna 101 and can perform azimuthal electromagnetic wave resistivity measurement using the tilted antenna 102, thus having multi-purpose functions.

[0049] It should be noted that, although only one axial antenna 101 and one tilted antenna 102 are provided in this embodiment, the present invention is not limited to this configuration, and the number of axial antennas 101 and tilted antennas 102 can be adjusted according to actual conditions.

[0050] like Figure 4FIG. 1 shows the installation process of the logging while drilling device 100 .

[0051] S401: Detector mounting slots 304 and circuit mounting slots 309 are machined on the outer wall of the non-magnetic drill collar 303. Detector mounting slot 304 does not require sealing and can be exposed to a high-pressure environment. Circuit mounting slot 309 requires sealing and maintains a low-pressure environment. A protective cover 301 is also machined and has a slit 302 formed in it to allow electromagnetic wave signals to pass through.

[0052] S402: The non-magnetic drill collar 303 is provided with a third, fourth, fifth, and sixth jacks 305, 306, 307, and 308, allowing for the threading of wires to electrically connect the detector mounting slot 304 to the circuit mounting slot 309. The measurement circuit 310 is installed in the circuit mounting slot 309 and sealed with high pressure.

[0053] S403: Snap housing 106 directly into detector mounting slot 304, and insert third pin 111, fourth pin 112, fifth pin 113, and sixth pin 114 into third jack 305, fourth jack 306, fifth jack 307, and sixth jack 308, respectively, to prevent the high voltage from detector mounting slot 304 from being transmitted to circuit mounting slot 309. Wires are soldered to third jack 305, fourth jack 306, fifth jack 307, and sixth jack 308, which are connected to measurement circuit 310 via the wires.

[0054] S404 : Cover the protective cover 301 on the housing 106 , and fix the protective cover 301 on the non-magnetic drill collar 303 with screws, thereby fixing the housing 106 in the detector installation slot 304 .

[0055] S405: According to different source distances and spacings, several detector installation grooves 304 are processed on the non-magnetic drill collar 303, and the housing 106 is installed in the grooves to form a logging while drilling instrument with multiple measurement functions.

[0056] This invention utilizes a modular design approach, constructing the logging-while-drilling device 100 into a circular tube. Multiple antenna structures and antenna impedance matching circuits (such as the axial antenna 101, tilted antenna 102, first circuit 104, and second circuit 105 provided in this embodiment) can be prefabricated within the tube. This solves the challenge of instrument antenna commissioning and facilitates installation, enabling rapid production of the logging-while-drilling instrument. Antenna replacement and instrument repair are possible on-site, significantly contributing to the scaled production of the instrument and reducing instrument operation and maintenance costs.

[0057] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0058] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0059] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0060] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A logging while drilling device, characterized in that: include: A housing (106), wherein the housing (106) is configured in a semicircular shape, and two housings (106) are engaged with each other so as to be detachably mounted on the downhole tool; An antenna is arranged in the housing (106), the antenna comprising an axial antenna (101) and a tilted antenna (102) staggeredly arranged in the housing (106), a first circuit (104) and a second circuit (105) adapted to each other are respectively arranged on the axial antenna (101) and the tilted antenna (102), the axial antenna (101) is used for performing conventional electromagnetic wave resistivity measurement, and the tilted antenna (102) is used for performing azimuthal electromagnetic wave resistivity measurement; A pin and a socket that are adapted to each other are provided between the contact surfaces of the two shells (106). After the pin and the socket are plugged into each other, the two shells (106) are fixedly connected on the one hand, and the partial axial antenna (101) and the partial tilted antenna (102) in the two shells (106) are electrically connected on the other hand, thereby forming a complete axial antenna (101) and a tilted antenna (102); A plurality of magnetic bars (103) are evenly arranged along the circumferential direction in the shell (106), and the central axis of the magnetic bars (103) is parallel to the central axis of the shell (106); A measurement circuit (310) is sealed and disposed in a downhole tool, and is connected to the axial antenna (101) and the tilted antenna (102) in a detachable manner.

2. The logging while drilling device according to claim 1, characterized in that: A detector installation groove (304) is provided on the downhole tool, and the housing (106) is provided in the detector installation groove (304).

3. The logging while drilling device according to claim 2, characterized in that: A circuit installation groove (309) is provided on the downhole tool, and the measurement circuit (310) is sealed and arranged in the circuit installation groove (309).

4. The logging while drilling device according to claim 3, characterized in that: A connecting wire is provided inside the downhole tool between the detector installation slot (304) and the circuit installation slot (309), one end of the connecting wire is connected to the measurement circuit (310), and the other end is connected to the antenna.

5. The logging while drilling device according to any one of claims 2 to 4, characterized in that: A protective cover (301) is provided outside the housing (106).

6. The logging while drilling device according to claim 5, characterized in that: A plurality of gaps (302) are evenly arranged along the circumference of the protective cover (301).

7. The logging while drilling device according to any one of claims 1 to 4, characterized in that: Both ends of the antenna extend from axial ends of the housing (106).

8. The logging while drilling device according to any one of claims 1 to 4, characterized in that: The axial antenna (101) is arranged in a ring shape within the housing (106), and the central axis of the ring formed by the axial antenna (101) is parallel to the central axis of the housing (106).

9. The logging while drilling device according to any one of claims 1 to 4, characterized in that: The tilted antenna (102) is arranged in a ring shape within the housing (106), and the central axis of the ring formed by the tilted antenna (102) and the central axis of the housing (106) are tilted relative to each other.

10. The logging while drilling device according to claim 4, characterized in that: The connecting wire is connected to the antenna in a detachable manner.

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