While-drilling transient electromagnetic shielding layer structure based on conductive and magnetic composite material

Abstract

The utility model relates to the technical field of while-drilling electromagnetic detection, in particular to a while-drilling transient electromagnetic shielding layer structure based on a conductive and magnetic composite material, which comprises an annular unit, an elastic connecting piece and a micro sensor. Each annular unit is of a three-layer composite structure, the outer layer is a carbon fiber woven layer, the middle layer is a ferrite particle embedded epoxy resin matrix, and the inner layer is a high-temperature-resistant insulating ceramic coating. The elastic connecting piece realizes flexible connection through a silica gel gasket and keeps electrical communication; the micro sensor is embedded into the middle layer and used for monitoring underground environment parameters. The device also comprises a grounding assembly, a temperature compensation assembly and other preferable designs. The method can adapt to underground dynamic working conditions, the shielding performance is optimized, and the electromagnetic signal shielding effect and reliability are remarkably improved.

Description

Technical Field

[0001] This utility model belongs to the field of measurement while drilling technology in the field of petroleum exploration and development technology, specifically a transient electromagnetic shielding layer structure based on conductive and magnetically conductive composite materials. Background Technology

[0002] Electromagnetic detection while drilling (EMS) systems are used in oil and gas exploration to monitor downhole geological information in real time. Their core function is to detect targets through the transmission and reception of electromagnetic signals. However, the metal components of the drill pipe significantly attenuate electromagnetic signals, affecting detection accuracy and data reliability. To address this issue, existing technologies have proposed various shielding solutions: coating the drill string surface with a single conductive coating (such as copper plating) to suppress some eddy current effects through conductivity; using a metal shielding sleeve of fixed thickness to wrap the drill pipe to reduce electromagnetic leakage; or employing a static electromagnetic shielding design to optimize shielding performance.

[0003] However, the above solutions have certain limitations. A single conductive material cannot simultaneously suppress eddy currents and magnetic losses, resulting in limited shielding efficiency. Fixed shielding structures are prone to detachment or failure when adapting to dynamic conditions such as drill string bending, high temperature, and high pressure. Furthermore, high-salinity drilling fluids alter the electromagnetic field distribution, and traditional shielding layers lack the ability to dynamically match impedance, further affecting the shielding effect. Utility Model Content

[0004] This invention relates to the field of electromagnetic detection while drilling (EMD), and more particularly to an EMD transient shielding layer structure based on a conductive and magnetically permeable composite material. The background art mentions the problem of significant attenuation of electromagnetic signals by the metal components of the drill pipe in existing EMD systems. To solve this problem, this invention proposes an EMD transient shielding layer structure based on a conductive and magnetically permeable composite material.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a transient electromagnetic shielding layer structure for drilling based on conductive and magnetically conductive composite materials, comprising annular units, elastic connectors and micro sensors, wherein the annular units are arranged along the drill pipe axis, each annular unit is 20cm long, and adjacent annular units are connected by elastic connectors.

[0006] The ring unit has a three-layer structure design: the outer layer is a carbon fiber braided layer, the middle layer is ferrite particles embedded in an epoxy resin matrix, and the inner layer is a high-temperature resistant insulating ceramic coating; the total thickness of the ring unit is 5mm, and the thickness ratio of the outer layer to the middle layer is 12.

[0007] The elastic connector is a silicone pad, with both ends of the silicone pad embedded in the end grooves of adjacent annular units, and a conductive path provided in the middle of the silicone pad.

[0008] The microsensor is embedded in the middle layer of the ring unit, with the ferrite particles embedded inside the epoxy resin matrix. The microsensor is connected to an external data acquisition module via wires.

[0009] To further realize this utility model, the following technical solutions may be preferred:

[0010] Preferably, it further includes a grounding component, the grounding component comprising:

[0011] The grounding terminal is fixedly fitted onto the inner high-temperature resistant insulating ceramic coating surface of the ring unit;

[0012] The conductive spring is shaped like a dot, with its two ends connected to the grounding terminal and its middle part resting against the surface of the drill rod.

[0013] Preferably, the elastic connector further includes a buffer mechanism, the buffer mechanism comprising:

[0014] The buffer cavity is located in the middle of the silicone pad and is filled with a polymer energy-absorbing material.

[0015] The conductive bridge is fixedly fitted into the buffer cavity, and its two ends are respectively welded to the outer carbon fiber braided layer of the adjacent annular unit.

[0016] Preferably, it further includes a temperature compensation component, the temperature compensation component comprising:

[0017] The thermistor has ferrite particles embedded in the middle layer of the ring unit embedded inside the epoxy resin matrix. The thermistor is connected to the external control module through wires.

[0018] The heat sink is fixedly attached to the surface of the outer carbon fiber braided layer of the ring unit and is made of aluminum alloy.

[0019] Preferably, the annular unit further includes a pressure balancing mechanism, the pressure balancing mechanism comprising:

[0020] The pressure chamber is located between the inner high-temperature resistant insulating ceramic coating and the middle ferrite particles embedded in the epoxy resin matrix of the annular unit, and is filled with inert gas.

[0021] Preferably, it further includes a signal enhancement component, the signal enhancement component comprising:

[0022] The signal amplifier has ferrite particles embedded in the middle layer of the ring unit embedded inside the epoxy resin matrix. The signal amplifier is connected to an external power supply through wires.

[0023] The magnetic core consists of middle-layer ferrite particles embedded within an epoxy resin matrix, which are fixedly fitted into the annular unit.

[0024] The beneficial effects of this utility model are:

[0025] This invention solves the problem that traditional fixed shielding structures are difficult to adapt to dynamic working conditions such as drill bit bending, high temperature and high pressure by dividing the shielding layer into multiple ring units and connecting them with elastic connectors, while improving the reliability and service life of the shielding layer.

[0026] Meanwhile, this utility model adopts a three-layer composite structure design. The outer layer is a carbon fiber braided layer that provides conductivity, the middle layer is a ferrite particle embedded in an epoxy resin matrix that provides magnetic conductivity, and the inner layer is a high-temperature resistant insulating ceramic coating that provides isolation. This optimizes the impedance matching performance of the shielding layer and effectively suppresses eddy currents and magnetic losses.

[0027] In addition, the design of the grounding component and signal enhancement component further improves the stability and reliability of the shielding layer, ensuring that it can maintain efficient electromagnetic shielding performance in complex downhole environments. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of this utility model.

[0029] Figure 2 This is a cross-sectional view of the structure of this utility model.

[0030] Figure 3 For the present utility model Figure 2 Sectional view at point AA.

[0031] The attached figures are labeled as follows:

[0032] 1-Ring unit; 2-Elastic connector; 3-Conductive spring; 4-Buffer cavity; 5-Conductive bridge; 6-Pressure cavity; 101-Carbon fiber braided layer; 102-Ferrite particles embedded in epoxy resin matrix; 103-High temperature resistant insulating ceramic coating; 201-Silicone gasket. Detailed Implementation

[0033] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0035] Example 1

[0036] This utility model relates to a transient electromagnetic shielding layer structure for drilling based on a conductive and magnetically permeable composite material, the specific implementation of which is as follows. Combined with... Figures 1 to 3 As shown, the structure includes annular units 1, elastic connectors 2, and microsensors. The annular units 1 are arranged axially along the drill pipe, with each segment 1 being 20cm long. Adjacent annular units 1 are connected by elastic connectors 2, allowing the drill bit to bend and deform. The annular unit 1 has a three-layer structure: an outer carbon fiber braided layer 101, a middle layer of ferrite particles embedded in an epoxy resin matrix 102, and an inner layer of high-temperature resistant insulating ceramic coating 103. The total thickness of the annular unit 1 does not exceed 5mm, and the thickness ratio of the outer layer to the middle layer is 1:2. The elastic connector 2 uses silicone gaskets 201, with both ends of the silicone gaskets 201 embedded in the end grooves of adjacent annular units 1. A conductive path is provided in the middle of the silicone gasket 201, enabling electrical connection between adjacent annular units 1. The microsensors are embedded in the middle layer of the annular unit 1, with the ferrite particles embedded inside the epoxy resin matrix 102. The microsensors are connected to an external data acquisition module via wires.

[0037] like Figures 1-3 As shown, the annular units 1 are arranged along the drill pipe axis, and adjacent annular units 1 are connected by elastic connectors 2, which are silicone gaskets 201. The silicone gaskets 201 are embedded at both ends into the end grooves of the annular units 1, with a groove depth of 1mm and a width of 2mm, ensuring that the silicone gaskets 201 can tightly fit the end faces of the annular units 1. A conductive bridge 5 is provided in the middle of the silicone gasket 201. The conductive bridge 5 is made of copper foil, with a thickness of 0.2mm and a width of 5mm. The two ends of the conductive bridge 5 are respectively welded to the outer carbon fiber braided layer 101 of the adjacent annular units 1, thereby achieving electrical connection between adjacent annular units 1. A buffer cavity 4 is provided in the middle of the silicone gasket 201, filled with a high-polymer energy-absorbing material, specifically polyurethane foam, which has excellent energy absorption performance. Limiting blocks are embedded at both ends of the buffer cavity 4. The limiting blocks are made of rigid plastic, with a thickness of 1mm and a width of 3mm, used to limit the deformation of the silicone gaskets 201 and prevent excessive stretching or compression of the elastic connectors 2 due to drill bending.

[0038] The annular unit 1 features a three-layer composite structure. The outer layer is a 1mm thick carbon fiber braided layer 101, woven from 0.1mm diameter carbon fiber filaments at a density of 50 filaments per square centimeter. This layer provides the main conductive path for the shielding layer. The middle layer is a 2mm thick ferrite particle embedded in an epoxy resin matrix 102, with 0.5mm diameter ferrite particles and a 30% particle filling rate. This layer provides the main magnetic permeability for the shielding layer. The inner layer is a 2mm thick high-temperature resistant insulating ceramic coating 6, sintered from alumina powder at 1200℃. This coating exhibits excellent high-temperature resistance and insulation properties, effectively isolating the shielding layer from the high-pressure environment downhole. The total thickness of the annular unit 1 is 5mm, with an outer layer to middle layer thickness ratio of 1:2. This ratio achieves an optimal balance between conductivity and magnetic permeability in the shielding layer.

[0039] The miniature sensor is embedded in the middle layer of ferrite particles within the epoxy resin matrix 102 of the annular unit 1. The miniature sensor is connected to an external data acquisition module via a shielded cable, which is further encased in a 0.1mm thick nickel alloy shield. This shield effectively prevents external electromagnetic interference from affecting the signal transmission of the miniature sensor. The miniature sensor monitors downhole environmental parameters such as temperature, pressure, and vibration in real time and transmits the data to the external data acquisition module.

[0040] The ring unit 1 also includes a grounding component, which includes a grounding terminal and a conductive spring 3. The grounding terminal is fixedly embedded in the surface of the inner high-temperature resistant insulating ceramic coating 103 of the ring unit 1. The grounding terminal is made of brass with a thickness of 2 mm and a width of 10 mm. The conductive spring 3 is made of beryllium bronze and is shaped like a ﹀. Its two ends are respectively connected to the grounding terminal and its middle part abuts against the drill rod surface. The conductive spring 3 provides stable contact pressure to ensure that the grounding terminal and the drill rod surface always maintain good contact.

[0041] The elastic connector 2 also includes a buffer mechanism, which comprises a buffer cavity 4 and a conductive bridge 5. The buffer cavity 4 is located in the middle of the silicone gasket 201, with a width of 5 mm and a height of 3 mm. The buffer cavity 4 is filled with a high-polymer energy-absorbing material, which is polyurethane foam. The energy-absorbing material can effectively absorb the stress generated when the drill bit bends. The conductive bridge 5 is fixedly embedded in the buffer cavity 4. The two ends of the conductive bridge 5 are respectively welded to the outer carbon fiber braided layer 101 of the adjacent annular unit 1. The conductive bridge 5 is made of copper foil, with a thickness of 0.2 mm and a width of 5 mm. The conductive bridge 5 maintains the electrical connection between the adjacent annular units 1, ensuring that the shielding layer can maintain stable shielding performance when the drill bit bends.

[0042] The ring unit 1 also includes a temperature compensation component, which comprises a thermistor and a heat sink. The thermistor, model NTC 10K, is embedded within the epoxy resin matrix 102 of the middle layer ferrite particles in the ring unit 1. The thermistor is connected to an external control module via a shielded cable, which is covered by a 0.1mm thick nickel alloy shield. This shield effectively prevents external electromagnetic interference from affecting the signal transmission of the thermistor. The heat sink is fixedly attached to the surface of the outer carbon fiber braided layer 101 of the ring unit 1. The heat sink is made of aluminum alloy, with a thickness of 1mm and a width of 10mm. This heat sink effectively reduces the temperature rise of the ring unit 1, improving the stability and reliability of the shielding layer.

[0043] The annular unit 1 also includes a pressure balancing mechanism, which includes a pressure chamber 6. The pressure chamber 6 is located between the inner high-temperature resistant insulating ceramic coating 103 and the middle ferrite particle embedded epoxy resin matrix 102 of the annular unit 1. The pressure chamber 6 has a width of 2 mm and a height of 1 mm. The pressure chamber 6 is filled with an inert gas, namely nitrogen, at a pressure of 0.5 MPa. The pressure chamber 6 can effectively balance the impact of downhole high pressure on the annular unit 1.

[0044] The ring unit 1 also includes a signal enhancement component, which comprises a signal amplifier and a magnetic core. The signal amplifier, model OPA2134, is embedded within the epoxy resin matrix 102 of the ring unit 1, with the middle layer of ferrite particles embedded within it. The signal amplifier is connected to an external power supply via a shielded cable, which is covered by a 0.1mm thick nickel alloy shield. This shield effectively prevents external electromagnetic interference from affecting the signal transmission of the signal amplifier. The magnetic core, made of a high-permeability material, has a diameter of 5mm and a length of 10mm. The magnetic core concentrates the magnetic field distribution, improving the shielding effect of the shielding layer.

[0045] The above are merely preferred embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this utility model, based on the technical solution and inventive concept of this utility model, should be included within the scope of protection of this utility model.

Claims

1. A transient electromagnetic shielding layer structure for drilling based on conductive and magnetically permeable composite materials, comprising a ring unit (1), an elastic connector (2), and a micro-sensor, characterized in that: The annular units (1) are arranged along the drill rod axis, and each annular unit (1) is 20cm long. Adjacent annular units (1) are connected by elastic connectors (2). The annular unit (1) has a three-layer structure design. The outer layer is a carbon fiber braided layer (101), the middle layer is ferrite particles embedded in an epoxy resin matrix (102), and the inner layer is a high-temperature resistant insulating ceramic coating (103). The total thickness of the annular unit (1) is 5mm, and the thickness ratio of the outer layer to the middle layer is 1:

2. The elastic connector (2) is a silicone pad (201). The two ends of the silicone pad (201) are respectively embedded in the end grooves of the adjacent annular unit (1), and a conductive path is provided in the middle of the silicone pad (201). The microsensor is embedded in the middle layer of the ring unit (1), where the ferrite particles are embedded inside the epoxy resin matrix (102). The microsensor is connected to an external data acquisition module via wires.

2. The drilling transient electromagnetic shielding layer structure based on conductive and magnetically permeable composite materials according to claim 1, characterized in that: It also includes a grounding component, the grounding component comprising: The grounding terminal is fixedly fitted onto the surface of the inner high-temperature resistant insulating ceramic coating (103) of the ring unit (1); The conductive spring (3) is ﹀-shaped, with its two ends connected to the grounding terminal and its middle part abutting against the surface of the drill rod.

3. The transient electromagnetic shielding layer structure based on conductive and magnetically permeable composite materials during drilling as described in claim 1, characterized in that: The elastic connector (2) further includes a buffer mechanism, which comprises: The buffer cavity (4) is located in the middle of the silicone pad (201), and the buffer cavity (4) is filled with a polymer energy-absorbing material. The conductive bridge (5) is fixedly fitted into the buffer cavity (4), and the two ends of the conductive bridge (5) are respectively welded to the outer carbon fiber braided layer (101) of the adjacent annular unit (1).

4. The transient electromagnetic shielding layer structure based on conductive and magnetically permeable composite materials during drilling according to claim 1, characterized in that: It also includes a temperature compensation component, which comprises: The thermistor has its middle layer ferrite particles embedded in the ring unit (1) embedded inside the epoxy resin matrix (102), and the thermistor is connected to the external control module through wires. The heat sink is fixedly attached to the surface of the outer carbon fiber braided layer (101) of the annular unit (1), and the heat sink is made of aluminum alloy.

5. The transient electromagnetic shielding layer structure based on conductive and magnetically permeable composite materials during drilling according to claim 1, characterized in that: The annular unit (1) further includes a pressure balancing mechanism, which comprises: The pressure chamber (6) is located between the inner high-temperature resistant insulating ceramic coating (103) and the middle ferrite particles embedded in the epoxy resin matrix (102) of the annular unit (1), and is filled with inert gas.

6. The transient electromagnetic shielding layer structure based on conductive and magnetically permeable composite materials during drilling as described in claim 1, characterized in that: It also includes a signal enhancement component, which includes: The signal amplifier has its middle layer ferrite particles embedded in the epoxy resin matrix (102) of the embedded ring unit (1), and the signal amplifier is connected to an external power supply through wires. The magnetic core is fixedly fitted with the middle layer of ferrite particles embedded in the epoxy resin matrix (102) of the annular unit (1).

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