CN109826618B - Nuclear magnetic resonance radio frequency coil capable of being used under high-salinity mud drilling fluid condition - Google Patents
Nuclear magnetic resonance radio frequency coil capable of being used under high-salinity mud drilling fluid condition Download PDFInfo
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- CN109826618B CN109826618B CN201910023691.XA CN201910023691A CN109826618B CN 109826618 B CN109826618 B CN 109826618B CN 201910023691 A CN201910023691 A CN 201910023691A CN 109826618 B CN109826618 B CN 109826618B
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
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- Y02A90/30—Assessment of water resources
Abstract
The invention discloses a nuclear magnetic resonance radio frequency coil capable of being used under the condition of high-salinity mud drilling fluid, which consists of two flexible PCBs (printed circuit boards), wherein the two flexible PCBs are tightly attached to a base with one arc-shaped surface, and a solenoid structure is integrally formed.
Description
Technical Field
The invention relates to the field of petroleum logging instruments, in particular to a nuclear magnetic resonance radio frequency coil which can be used under the condition of high-salinity mud drilling fluid.
Background
In a nuclear magnetic resonance imaging logging instrument, a nuclear magnetic resonance technology is widely applied to the fields of life medical treatment, geophysical, food analysis, material science and the like as a nondestructive testing means. The rf coil is a dedicated device for transmitting and receiving rf signals, or a source device for providing an nmr frequency, which is critical to the imaging quality and easy to develop and optimize relative to other components, and thus has been a hot issue in the field of MRI research. In nmr logging, the rf coil mainly generates a static rf magnetic field perpendicular to the main magnet field. The existing underground centering nuclear magnetic resonance logging instrument uses a saddle-shaped coil structure, a radio frequency magnetic field generated by the saddle-shaped coil structure has high matching performance with a static magnetic field, and formation rock sample information which is a circle of a certain fixed distance away from the outside of the coil is detected, so that a high signal-to-noise ratio can be obtained. Correspondingly, due to the adoption of a circumferential detection mode, under the condition that the borehole is greatly enlarged, invalid noise information of mud filtrate can be detected, and application limitation is caused.
On the other hand, the saddle coil can reach the stratum only through borehole mud due to the radio frequency magnetic field during measurement, and borehole fluid plays a load role and generates loss on radio frequency energy, so that the signal to noise ratio is reduced. At present, a small-sized well-wall-sticking nuclear magnetic antenna body with high resolution and less influence of the well environment is urgently needed.
Disclosure of Invention
The invention aims to provide a nuclear magnetic resonance radio frequency coil which can be used under the condition of high-salinity slurry drilling fluid, and aims to solve the problem that a nuclear magnetic resonance antenna of a centering instrument cannot be used under the condition of high-salinity shaft solution.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides a nuclear magnetic resonance radio frequency coil that can be used to under high salinity mud drilling fluid condition, includes flexible board, lower flexible board and base, it is the PCB board with lower flexible board to go up the flexible board, the upper surface of base is the arcwall face, goes up the flexible board setting on the upper surface of base, and lower flexible board sets up on the lower surface of base, and has arranged three wires on going up flexible board and the lower flexible board respectively, goes up three wires on the flexible board and the welding of three wires head and the tail on the flexible board down, is solenoid structure winding on the base, forms two circle coils, and the head end of a wire on the last flexible board of last flexible board and the end of a wire on the lower flexible board are as two excitation input points, or go up the end of a wire on the flexible board and the head end of a wire on the flexible board down as two excitation input points.
Furthermore, the whole upper flexible plate is rectangular, the middle part of the lower flexible plate is rectangular, and two ends of the lower flexible plate are fan-shaped.
Furthermore, the upper flexible plate is provided with a plurality of fixing holes for conveniently installing the upper flexible plate on the base, the rectangular structure of the lower flexible plate is provided with a plurality of fixing holes for conveniently installing the lower flexible plate on the base, and the fan-shaped structure of the lower flexible plate is provided with a plurality of positioning holes for enabling the lower flexible plate to tightly adhere to the base.
Furthermore, the base materials of the upper flexible plate and the lower flexible plate are made of polyimide, the conducting wire is made of electrolytic copper, and the base material is made of polytetrafluoroethylene.
Furthermore, the three wires on the upper flexible board are uniformly arranged at equal intervals, and the three wires on the lower flexible board are uniformly arranged at equal intervals.
Furthermore, one end of the lead positioned on one side of the base on the lower flexible board extends out of the lower flexible board, and two ends of the rest two leads on the lower flexible board extend out of the lower flexible board.
Furthermore, the end parts of the three conducting wires on the upper flexible board and the end parts of the three conducting wires on the lower flexible board are respectively provided with a bonding pad, and the three conducting wires on the upper flexible board and the three conducting wires on the lower flexible board are welded end to end through the bonding pads.
Furthermore, one end of a wire on one side of the base on the lower flexible board, which extends out of the lower flexible board, is welded with one end of a wire on one side of the base on the upper flexible board, the other end of the wire on one side of the base on the upper flexible board is welded with one end of a wire on the middle of the lower flexible board, the other end of the wire on the middle of the lower flexible board is welded with one end of a wire on the middle of the upper flexible board, the other end of the wire on the other side of the base on the upper flexible board is welded with one end of a wire on the other side of the base on the upper flexible board, the other end of the wire on one side of the base on the lower flexible board is welded with one end of a wire on the other side of the base on the upper flexible board, and the other end of the wire on one side of the base on the lower flexible board and the other end of the wire on the other side of the base on the upper flexible board are used as two excitation input points.
Compared with the prior art, the invention has the following beneficial technical effects:
the antenna adopts a winding wire structure, and has higher inductance and emission efficiency compared with a plane antenna, so that higher detection sensitivity can be obtained under the condition of not using a magnetic core. The structure design not only greatly simplifies the structure of the nuclear magnetic antenna, but also avoids additional adverse factors of static magnetic fields caused by using magnetic core materials. The antenna has directivity in emission, so that the antenna can be used under any borehole size as long as the antenna is tightly attached to the borehole wall in the using process, and meanwhile, the antenna is tightly attached to the borehole wall, so that the emitted electromagnetic waves can be prevented from directly entering a stratum without mud, the attenuation of the mud to the electromagnetic waves is avoided, namely, the antenna can be used under any mud drilling fluid conductivity condition; in addition, because the distance between the antenna and the detection area is short, a stronger radio frequency signal can reach a sensitive area, therefore, a narrower radio frequency pulse can cause a wider frequency band to be activated, the nuclear magnetic resonance system can be used for building a nuclear magnetic resonance system to detect formation nuclear magnetic resonance signals, and measured data can be directly used for petrophysical analysis and well logging interpretation to determine parameters such as oil (or water) saturation, total porosity, small porosity, bound content, T2 spectral distribution, permeability and the like.
Further, through setting up the fixed orifices, can adopt the screw to fix earlier during the installation, demolish after accomplishing the installation again, can easy to assemble, through setting up the locating hole, can make down the laminating of flexbile plate and base better.
Drawings
Fig. 1 is a schematic structural diagram of a radio frequency coil according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a radio frequency coil wire connection provided in accordance with an embodiment of the present invention;
FIG. 3 is a schematic diagram of a flexible board on a radio frequency coil according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a lower flexible board of a radio frequency coil according to an embodiment of the present invention;
fig. 5 is a diagram illustrating a magnetic field distribution generated by a radio frequency coil according to an embodiment of the present invention.
In the figure, A1-A6 are pads on the upper flexible board; B1-B6 are pads on the lower flexible board; 21-24 are fixing holes on the upper flexible plate; 16-19 are fixing holes on the lower flexible plate; 1-15 are positioning holes on the lower flexible plate; 25 is a borehole; and 26 is a detection sensitive area.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings:
referring to fig. 1 to 5, a nuclear magnetic resonance radio frequency coil for use in the condition of a highly mineralized mud drilling fluid, the coil structure is composed of two PCB boards (an upper flexible board and a lower flexible board) from which connection terminals are led out, and a base with an arc-shaped surface. The upper flexible board and the lower flexible board are tightly adhered to an antenna base, the two sides of the base are connected by welding wires, the whole solenoid structure is wound on the base, three wires are distributed on the two PCB boards, the two PCB boards are welded on the cambered surface of the base to form a two-turn coil and are provided with two excitation input points, a large alternating current signal is provided for the whole coil from the input points, the two PCB boards are flexible boards, three parallel wires are distributed on the boards, welding spots capable of being welded are arranged at the two ends of each flexible board, the flexible boards are made of polyimide, the wires are made of electrolytic copper and are double-layer boards, the wires are uniformly arranged at equal intervals, connecting terminals are respectively led out from the two ends of the two flexible boards, the connecting terminals led out from the two flexible boards are welded on the end surface of a framework, the connecting terminals led out from the two flexible boards are welded by bonding pads, and tin-permeating holes are reserved on the bonding pads so that the wires are stably connected, and one flexible board is tightly adhered to the cambered surface of the base, one slice hugs closely on the base bottom surface, two are welded at the cambered surface through the pad, one end at the base is each left one and is encouraged the input end down, the binding post that the flexible sheet that is located on the base sector draws needs smooth transition and the flexible sheet of bottom surface to weld, binding post turning radian requires to be 35, the flexible sheet has locating hole and folding line, so that the installation, make the flexible sheet laminate the antenna base better, during the use, radio frequency coil is fixed in the main magnet that has fan-shaped recess through fixing device, the required radio frequency magnetic field of resonance condition is formed in the excitation, carry out nuclear magnetic resonance imaging logging.
The following is a detailed description of the operation of the present invention:
the invention adopts two flexible PCBs and a polytetrafluoroethylene material base, and the two flexible PCBs form a current path on the end surface of the base through welding. The number of turns of a coil formed by the structure is 2 and a half turns, each turn of the coil is similar to a rectangular structure, the turn-to-turn distance of each turn of the coil is equal, all sides of the coil are mutually parallel, and an excitation input point and an excitation output point are arranged on the upper layer and the lower layer of the base. The excitation source enters from the excitation input point of one layer and flows out from the excitation output point of the other layer, and in order to fix the coil, a 3M adhesive tape is needed to be tightly attached to the base.
As shown in fig. 1, the wall-mounted nuclear magnetic antenna structure is composed of two flexible boards and an antenna base, and two points are ensured during installation: 1. the flexible plate is well attached to the base; 2. the upper and lower flexible boards are welded firmly at the end faces through the welding pads.
The method comprises the following specific implementation steps: the two flexible boards are double-sided PCB boards, the PCB base material is high-temperature resistant polyimide material, and the conducting wire material is electrolytic copper. Wherein, the upper flexible plate is of a rectangular structure, the length is 65cm, the width is 9.5cm, and the upper flexible plate is arranged on the upper cambered surface of the base, as shown in figure 3; the middle of the lower flexible board is of a rectangular structure, the length of the lower flexible board is 80cm, the width of the lower flexible board is 13cm, the two ends of the lower flexible board are of fan-shaped structures, and terminals for wiring protrude out of the fan-shaped structures and are arranged on the lower bottom surface of the base, as shown in fig. 4. The upper flexible board is provided with pads A1, A2, A3, A4, A5, A6 and fixing holes 21,22,23 and 24, so that the upper flexible board is convenient to mount, is fixed by M3 screws during mounting and is dismounted after mounting is finished. The lower flexible board is provided with pads B2, B3, B4, B5 and B6 which are respectively welded with pads A2, A3, A4, A5 and A6, and lead-free high-temperature soldering tin is adopted for welding; in addition, positioning holes 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 are used for better adhering to the base, and fixing holes 16,17,18,19 are also fixed firstly and then removed when being installed.
Fig. 5 shows the distribution of the alternating magnetic field generated by the antenna. When the antenna assembly is used, the antenna assembly needs to be tightly attached to the well wall of the borehole 25, and the underground electronic instrument generates an excitation signal with a certain bandwidth and transmits the excitation signal to the stratum through the antenna, so that an alternating magnetic field is generated. According to the nuclear magnetic resonance principle, the radio frequency pulse with fixed frequency only excites the nuclear magnetic resonance field in the matched magnetic field intensity area (detection sensitive area 26), so that the detection depth of the antenna can be changed by changing the working frequency loaded on the antenna. The deeper the probe depth, the weaker the signal that can be received. In order to achieve both sounding depth and signal strength, it is recommended that the antenna be used in the frequency range of 500K-1 MHz.
Claims (8)
1. The utility model provides a nuclear magnetic resonance radio frequency coil that can be used to under high salinity mud drilling fluid condition, its characterized in that, includes flexible board, lower flexible board and base, it is the PCB board with lower flexible board to go up the flexible board, the upper surface of base is the arcwall face, goes up the flexible board setting on the upper surface of base, and lower flexible board sets up on the lower surface of base, and has arranged three wires on going up flexible board and the lower flexible board respectively, goes up three wires on the flexible board and three wire end to end welding on the lower flexible board, is solenoid structure winding on the base, forms two turns of coil, and the head end of going up a wire on the flexible board and the end of a wire on the lower flexible board as two excitation input points, or the end of a wire on the last flexible board and the head end of a wire on the lower flexible board are as two excitation input points.
2. The NMR RF coil of claim 1, wherein the upper flexplate is rectangular in shape as a whole, and the lower flexplate is rectangular in shape at the middle and has fan-shaped ends.
3. The NMR RF coil of claim 2, wherein the upper flexplate has a plurality of holes for facilitating mounting of the upper flexplate on the base, the lower flexplate has a rectangular structure with a plurality of holes for facilitating mounting of the lower flexplate on the base, and the lower flexplate has a fan-shaped structure with a plurality of holes for securing the lower flexplate to the base.
4. The NMR RF coil of claim 1, wherein the upper and lower flexible plates are made of polyimide, the conductive wire is made of electrolytic copper, and the base is made of PTFE.
5. The RF coil of claim 1, wherein the three wires of the upper flexible plate are uniformly spaced and the three wires of the lower flexible plate are uniformly spaced and can be used in a highly mineralized mud drilling fluid.
6. The NMR RF coil of claim 1, wherein the end of the lead on the lower flexplate on the base side extends beyond the lower flexplate, and both ends of the remaining two leads on the lower flexplate extend beyond the lower flexplate.
7. The NMR RF coil of claim 6, wherein the three wires on the upper flexible board and the three wires on the lower flexible board are provided with bonding pads at their ends, and the three wires on the upper flexible board and the three wires on the lower flexible board are welded end to end via the bonding pads.
8. The nuclear magnetic resonance radio frequency coil used under the condition of the high salinity mud drilling fluid according to the claim 7, the flexible circuit board is characterized in that one end, extending out of one side of a base, of a lead on one side of the base, of a lower flexible board is welded with one end, located on one side of the base, of the lead on the upper flexible board, the other end, located on one side of the base, of the lead on the lower flexible board is welded with one end, located in the middle, of the lead on the upper flexible board, the other end, located in the middle, of the lead on the upper flexible board is welded with one end, located on the other side of the base, of the lead on the lower flexible board, the other end, located on the other side of the base, of the lead on the upper flexible board is welded with one end, located on the other side of the base, of the lead on one side of the base on the lower flexible board and the other end, located on the other side of the base, of the lead on the upper flexible board are used as two excitation input points.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910023691.XA CN109826618B (en) | 2019-01-10 | 2019-01-10 | Nuclear magnetic resonance radio frequency coil capable of being used under high-salinity mud drilling fluid condition |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910023691.XA CN109826618B (en) | 2019-01-10 | 2019-01-10 | Nuclear magnetic resonance radio frequency coil capable of being used under high-salinity mud drilling fluid condition |
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| CN109826618A CN109826618A (en) | 2019-05-31 |
| CN109826618B true CN109826618B (en) | 2022-06-03 |
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| CN113266342B (en) * | 2021-06-22 | 2022-05-17 | 华中科技大学 | Signal wireless transmitting device |
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| CN102444400A (en) * | 2011-11-15 | 2012-05-09 | 中国石油大学(北京) | Nuclear magnetic resonance fluid analyzer probe and nuclear magnetic resonance fluid analyzer |
| CN103645451A (en) * | 2013-12-06 | 2014-03-19 | 东南大学 | Low field nuclear magnetic resonance probe based on printed circuit board helmholtz coil |
| CN103674997A (en) * | 2013-12-06 | 2014-03-26 | 东南大学 | Low-field nuclear magnetic resonance probe based on solenoid coils of printed circuit board |
| CN205193258U (en) * | 2015-11-30 | 2016-04-27 | 上海联影医疗科技有限公司 | A RF coil array for magnetic resonance system |
| CN205609751U (en) * | 2016-05-12 | 2016-09-28 | 北京森馥科技股份有限公司 | Magnetic field antenna panel , three -dimensional magnetic field antenna and magnetic field probe |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US9519037B2 (en) * | 2011-11-10 | 2016-12-13 | Mayo Foundation For Medical Education And Research | Spatially coincident MRI receiver coils and method for manufacturing |
| AU2013327016A1 (en) * | 2012-10-04 | 2015-04-30 | Niitek, Inc. | Shieldings for metal detector heads and manufacturing methods thereof |
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| CN102444400A (en) * | 2011-11-15 | 2012-05-09 | 中国石油大学(北京) | Nuclear magnetic resonance fluid analyzer probe and nuclear magnetic resonance fluid analyzer |
| CN103645451A (en) * | 2013-12-06 | 2014-03-19 | 东南大学 | Low field nuclear magnetic resonance probe based on printed circuit board helmholtz coil |
| CN103674997A (en) * | 2013-12-06 | 2014-03-26 | 东南大学 | Low-field nuclear magnetic resonance probe based on solenoid coils of printed circuit board |
| CN205193258U (en) * | 2015-11-30 | 2016-04-27 | 上海联影医疗科技有限公司 | A RF coil array for magnetic resonance system |
| CN205609751U (en) * | 2016-05-12 | 2016-09-28 | 北京森馥科技股份有限公司 | Magnetic field antenna panel , three -dimensional magnetic field antenna and magnetic field probe |
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