CN115288666A - Nuclear magnetic logging while drilling instrument probe with separated transmitting and receiving coils - Google Patents
Nuclear magnetic logging while drilling instrument probe with separated transmitting and receiving coils Download PDFInfo
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- 239000000523 sample Substances 0.000 title claims abstract description 65
- 230000005291 magnetic effect Effects 0.000 title claims abstract description 40
- 238000005553 drilling Methods 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 claims description 19
- 230000008569 process Effects 0.000 claims description 18
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 2
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- 238000005481 NMR spectroscopy Methods 0.000 abstract description 41
- 238000005259 measurement Methods 0.000 abstract description 8
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- 230000005415 magnetization Effects 0.000 abstract description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 20
- 229910052739 hydrogen Inorganic materials 0.000 description 20
- 239000001257 hydrogen Substances 0.000 description 20
- 230000005284 excitation Effects 0.000 description 12
- 239000012530 fluid Substances 0.000 description 10
- 230000003068 static effect Effects 0.000 description 8
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- 230000015572 biosynthetic process Effects 0.000 description 6
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- 238000001514 detection method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 239000003129 oil well Substances 0.000 description 3
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- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/09—Locating or determining the position of objects in boreholes or wells, e.g. the position of an extending arm; Identifying the free or blocked portions of pipes
- E21B47/092—Locating or determining the position of objects in boreholes or wells, e.g. the position of an extending arm; Identifying the free or blocked portions of pipes by detecting magnetic anomalies
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
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Abstract
本发明属于核磁共振测井技术领域，提供一种收发线圈分离的随钻核磁测井仪探头，包括：探头骨架、第一永磁体和第二永磁体、发射线圈、第一接收线圈和第二接收线圈。所述探头骨架外形为长圆柱形，在探头骨架中心设有泥浆通孔，在探头骨架的外壁与泥浆通孔之间的空间区域内上下位置对称设置了第一和第二永磁体，第一和第二环形永磁体充磁方向与探头骨架的轴向重合、充磁极性相对；在探头骨架中间位置绕制发射线圈，在发射线圈与第一环形永磁体以及发射线圈与第二环形永磁体之间对称设有第一和第二接收线圈，其匝数相同、极性相反，以串联方式连接并输出。本发明使收发线圈的参数设计具有独立性，无需具有隔离和切换功能的收发复用电路，简化仪器设计、提高可靠性、改善信噪比、提高测量精度。
The invention belongs to the technical field of nuclear magnetic resonance logging, and provides a nuclear magnetic logging tool probe with separate transceiver coils while drilling, comprising: a probe skeleton, a first permanent magnet and a second permanent magnet, a transmitting coil, a first receiving coil and a second receive coil. The probe skeleton has a long cylindrical shape, a mud through hole is arranged in the center of the probe skeleton, and first and second permanent magnets are symmetrically arranged up and down in the space area between the outer wall of the probe skeleton and the mud through hole. The magnetizing direction of the second annular permanent magnet coincides with the axial direction of the probe skeleton, and the magnetization polarity is opposite; the transmitting coil is wound at the middle position of the probe skeleton, and the transmitting coil and the first annular permanent magnet and the transmitting coil and the second annular permanent magnet are The first and second receiving coils are symmetrically arranged between them, and the number of turns is the same and the polarity is opposite, which are connected in series and output. The invention makes the parameter design of the transceiver coil independent, without the transceiver multiplexing circuit with isolation and switching functions, simplifies instrument design, improves reliability, improves signal-to-noise ratio, and improves measurement accuracy.
Description
技术领域technical field
本发明属于核磁共振测井技术领域，尤其涉及一种收发线圈分离的随钻核磁测井仪探头。The invention belongs to the technical field of nuclear magnetic resonance logging, and in particular relates to a probe of a nuclear magnetic logging tool while drilling with separate transceiver coils.
背景技术Background technique
随钻核磁共振测井仪利用核磁共振原理测量油井周围的地层情况，从而探测地层中含氢流体的相关信息。具体来说随钻核磁共振测井仪通过探头来形成测量所需的静磁场和激发场，通过激发油井周围的含氢流体产生核磁共振信号，然后接收和分析核磁共振信号来获得地层中氢核的相关参数，进而测得地层中含氢流体的相关信息，比如含氢流体在地层中的体积百分比含量、含氢流体的流动特性和导电特性等信息。The logging-while-drilling nuclear magnetic resonance tool uses the principle of nuclear magnetic resonance to measure the formation conditions around the oil well, so as to detect the relevant information of the hydrogen-containing fluid in the formation. Specifically, the NMR logging tool while drilling uses a probe to form the static magnetic field and excitation field required for measurement, and generates NMR signals by exciting the hydrogen-containing fluid around the oil well, and then receives and analyzes the NMR signals to obtain the hydrogen nuclei in the formation. The relevant parameters of the formation, and then measure the relevant information of the hydrogen-containing fluid in the formation, such as the volume percentage of the hydrogen-containing fluid in the formation, the flow characteristics and conductivity characteristics of the hydrogen-containing fluid, etc.
其中，探头是随钻核磁共振测井仪在油井周围建立静磁场和产生激发场进而激发层中含氢流体产生核磁共振现象和接收核磁共振信号的关键部件，探头的结构设计决定了探测敏感区的范围、核磁共振测井仪的测量方式、产生核磁共振信号的强度以及接收到的核磁共振信号的原始信噪比等关键性能。Among them, the probe is a key component for the NMR logging tool to establish a static magnetic field around the oil well and generate an excitation field to excite the hydrogen-containing fluid in the layer to generate NMR phenomena and receive NMR signals. The structural design of the probe determines the detection of sensitive areas. The range of the NMR logging tool, the measurement method of the NMR logging tool, the strength of the generated NMR signal, and the original signal-to-noise ratio of the received NMR signal.
现有技术中的随钻核磁共振测井仪探头的结构如图1所示，探头呈长圆柱形，主要包括：探头骨架10、上下对称设置的两个永磁体13和14及中间位置收发复用的线圈15。其中探头骨架10包括居中的泥浆通孔11和探头外壳12；上下对称设置的两个永磁体13和14磁极相对设置，这样的设置会在敏感区M形成较为均匀的静磁场B0。线圈15是收发复用的，发射状态下的收发复用线圈15在随钻核磁共振测井仪发射电路的驱动下产生交变的激发场B1，交变激发场B1的方向与静磁场B0的方向垂直。敏感区M内的流体所含的氢核在激发场B1的作用下吸收能量进入高能态。激发停止后收发复用线圈15切换到接收状态，探测敏感区内的氢核在由高能态逐步恢复热稳态的过程中产生核磁共振现象，核磁共振的过程叫做弛豫过程，所用的时间称为弛豫时间。在此弛豫时间内探测敏感区M内的氢流体的磁共振现象会引发接收线圈周围磁场周期性变化，因而在接收线圈中形成感应电压信号，也就是接收线圈接收到的核磁共振信号。在弛豫时间内接收线圈输出的内核磁共振信号由强变弱，最终消失。The structure of the probe of the NMR logging tool in the prior art is shown in Figure 1. The probe is in the shape of a long cylinder and mainly includes: a
现有技术的随钻核磁共振测井仪探头中的线圈是收发复用的，因此，该线圈需要同时满足发射和接收电路的约束，比如线圈线径、匝数、结构、安装位置等条件。如图1所示，由于这些约束导致了收发复用的线圈15只能安装在探头10的中心位置且线径较粗、匝数较少，这就造成了复用线圈15作为接收线圈时等效接收面积较小、抗干扰能力较差、测量结果的信噪比较低。此外，复用线圈15需要一个收发复用电路，该电路用来实现高压隔离和全速切换功能，收发复用电路增加了随钻核磁共振测井仪的复杂度，降低了随钻核磁共振测井仪的整体可靠性。The coil in the probe of the existing NMR logging tool in the prior art is multiplexed by sending and receiving. Therefore, the coil needs to meet the constraints of the transmitting and receiving circuits at the same time, such as coil diameter, number of turns, structure, installation location and other conditions. As shown in Figure 1, due to these constraints, the
发明内容Contents of the invention
本发明所要解决的技术问题在于提供一种收发线圈分离的随钻核磁测井仪探头，采用了分离的发射线圈和接收线圈，消除了现有技术体系收发复用过程中对线圈的共性约束，使发射线圈线径较粗、匝数较少、居中安装，使接收线圈由两个线径较细、匝数较多的线圈组成，分别位于发射线圈轴向上部和下部对称安装，且两个线圈匝数相同、反极性串联后输出信号。本发明达到了增加接收线圈等效接收面积，提高接收信号幅度；对称结构消除环境干扰影响，改善信噪比；无需收发复用电路，降低系统复杂度，提高可靠性等目的。The technical problem to be solved by the present invention is to provide a probe of a nuclear magnetic logging tool while drilling with separate transmitting and receiving coils, which adopts separate transmitting coils and receiving coils, which eliminates the common constraints on the coils in the process of transmitting and receiving multiplexing in the prior art system, The transmitting coil has a thicker wire diameter, fewer turns, and is installed in the center, and the receiving coil is composed of two coils with thinner wire diameters and more turns, which are respectively installed symmetrically on the upper and lower parts of the transmitting coil axis, and the two The coils have the same number of turns and are connected in series with opposite polarities to output signals. The invention achieves the purposes of increasing the equivalent receiving area of the receiving coil, increasing the received signal amplitude, eliminating the influence of environmental interference by the symmetrical structure, improving the signal-to-noise ratio, eliminating the need for a transceiver multiplexing circuit, reducing system complexity, and improving reliability.
本发明是这样实现的，The present invention is achieved like this,
一种收发线圈分离的随钻核磁测井仪探头，所述探头包括：探头骨架、设置在探头骨架两端并与探头骨架同轴设置的第一环形永磁体和第二环形永磁体、设置在探头骨架中间位置的发射线圈、以及发射线圈上下两端对称设置的第一接收线圈和第二接收线圈。A probe for nuclear magnetic logging while drilling with separate transceiver coils, the probe comprises: a probe frame, a first annular permanent magnet and a second annular permanent magnet arranged at both ends of the probe frame and coaxially arranged with the probe frame, arranged on The transmitting coil at the middle position of the probe frame, and the first receiving coil and the second receiving coil arranged symmetrically at the upper and lower ends of the transmitting coil.
进一步地：所述探头骨架外形为长圆柱形，在所述探头骨架中心设有泥浆通孔；在所述探头骨架的外壁与所述泥浆通孔之间的空间区域内上下位置对称设置第一环形永磁体和第二环形永磁体，所述第一环形永磁体和第二环形永磁体沿探头骨架轴向充磁、充磁极性相同的一端相对；在第一接收线圈和第二接收线圈分别设置在所述发射线圈与所述第一环形磁体以及所述发射线圈与第二环形磁体之间。Further: the profile of the probe frame is long cylindrical, and a mud through hole is provided in the center of the probe frame; in the space area between the outer wall of the probe frame and the mud through hole, the first vertical position is symmetrically arranged. A ring-shaped permanent magnet and a second ring-shaped permanent magnet, the first ring-shaped permanent magnet and the second ring-shaped permanent magnet are magnetized along the axial direction of the probe frame and opposite to one end with the same magnetization polarity; the first receiving coil and the second receiving coil are respectively disposed between the transmitting coil and the first ring magnet and between the transmitting coil and the second ring magnet.
进一步地：所述第一接收线圈和第二接收线圈匝数相同以及极性相反，并且所述第一接收线圈和第二接收线圈以串联方式连接输出。Further: the number of turns of the first receiving coil and the second receiving coil are the same and the polarity is opposite, and the first receiving coil and the second receiving coil are connected in series for output.
进一步地：所述发射线圈和接收线圈使用铜线缆或银线缆，在所述探头骨架上螺旋缠绕，形成螺旋状的导电线缆。Further: the transmitting coil and the receiving coil use copper cables or silver cables, which are spirally wound on the probe frame to form a helical conductive cable.
进一步地：缠绕发射线圈和接收线圈所使用的导电线缆的截面形状、线缆线径、线圈匝数根据发射和接收的需要分别进行优化设计，所述发射线圈线径大于接收线圈的线径、匝数小于接收线圈的匝数。Further: the cross-sectional shape, cable diameter, and number of coil turns of the conductive cable used to wind the transmitting coil and the receiving coil are optimized and designed respectively according to the needs of transmitting and receiving, and the wire diameter of the transmitting coil is larger than the wire diameter of the receiving coil , The number of turns is less than the number of turns of the receiving coil.
进一步地：所述接收线圈在整个测量过程中始终直接与接收放大电路相连。Further: the receiving coil is always directly connected to the receiving amplifying circuit throughout the measurement process.
本发明与现有技术相比，有益效果在于：Compared with the prior art, the present invention has the beneficial effects of:
(1)使收发线圈分离，可以根据发射线圈和接收线圈的需要，分别设计线径、匝数和安装位置等参数，使收发线圈的参数设计具有独立性，从而优化各自的应用效果。推荐发射线圈采用粗线径、少匝数的线圈且中心安装，接收线圈采用较细线径、较多匝数的线圈且与发射线圈同轴对称安装。(1) To separate the transmitting and receiving coils, parameters such as wire diameter, number of turns, and installation position can be designed separately according to the needs of the transmitting and receiving coils, so that the parameter design of the transmitting and receiving coils is independent, thereby optimizing their respective application effects. It is recommended that the transmitting coil adopt a coil with a thick wire diameter and a few turns and install it in the center, and the receiving coil adopt a coil with a thin wire diameter and a large number of turns and install it coaxially and symmetrically with the transmitting coil.
(2)由于两个匝数相同、反极性串联的接收线圈处在发射线圈上下的对称位置，造成在发射线圈产生交变激发场的过程中两个接收线圈产生的感应电动势彼此对消，也就是在发射过程中接收线圈不会感应到发射信号。因此，接收线圈可以在整个测量过程中始终直接与接收放大电路相连，无需具有隔离和切换功能的收发复用电路。取消了收发复用电路会带来两个方面的好处：(2) Since two receiving coils with the same number of turns and opposite polarity connected in series are located at symmetrical positions above and below the transmitting coil, the induced electromotive forces generated by the two receiving coils cancel each other out when the transmitting coil generates an alternating excitation field. That is, the receiving coil will not sense the transmitting signal during the transmitting process. Therefore, the receiving coil can always be directly connected to the receiving amplifier circuit during the whole measurement process, without the need of a transceiver multiplexing circuit with isolation and switching functions. The cancellation of the transceiver multiplexing circuit will bring two benefits:
其一是简化随钻核磁共振测井仪的整机电路，降低系统复杂度，提高可靠性；One is to simplify the whole machine circuit of the NMR logging tool while drilling, reduce the complexity of the system and improve the reliability;
其二是消除了隔离切换过程对接收电路的影响，提高了探测速度、改善了信号质量。The second is to eliminate the influence of the isolation switching process on the receiving circuit, improve the detection speed and improve the signal quality.
(3)探测敏感区为一圆环状，位于探头外部，与发射线圈径向水平(注：原来是共面)，圆环中心与探头中心重合。在激发后，敏感区内流体含有的氢核产生核磁共振现象，也就是在敏感区产生交变的磁场。由于，两个接收线圈的轴心也与探头轴心重合并对称分布于发射线圈的上部和下部，因此，磁共振现象产生的交变磁场在两个接收线圈中的变化的极性正好是相反的，即上部接收线圈的磁通量增强，下部的就减弱，反之亦然。由于两个接收线圈采用的是反极性串联结构，因此敏感区交变磁场在两个接收线圈中产生的感应电动势是叠加的，也就是说两个接收线圈对于核磁共振信号具有叠加增强效果。(3) The detection sensitive area is a circular ring, which is located outside the probe and is radially horizontal to the transmitting coil (note: it was originally coplanar), and the center of the ring coincides with the center of the probe. After excitation, the hydrogen nuclei contained in the fluid in the sensitive area produce nuclear magnetic resonance, that is, an alternating magnetic field is generated in the sensitive area. Since the axes of the two receiving coils also coincide with the axes of the probe and are symmetrically distributed on the upper and lower parts of the transmitting coil, the polarity of the change of the alternating magnetic field generated by the magnetic resonance phenomenon in the two receiving coils is just opposite. , that is, the magnetic flux of the upper receiving coil is enhanced, and the lower one is weakened, and vice versa. Since the two receiving coils adopt a reverse polarity series structure, the induced electromotive force generated by the alternating magnetic field in the sensitive area in the two receiving coils is superimposed, that is to say, the two receiving coils have a superimposed and enhanced effect on the nuclear magnetic resonance signal.
两个匝数相同、反极性串联的接收线圈对于较远的干扰来说，两个线圈到干扰源的距离基本相同，因此，干扰源在两个接收线圈中产生的感应电动势大小基本相同但极性相反，在接收线圈中会相互对消，不产生输出信号，也就是两个匝数相同、反极性串联的接收线圈对较远的干扰具有对消作用，有益效果是能够提高信噪比、改善测量精度。Two receiving coils with the same number of turns and opposite polarity connected in series have basically the same distance from the two coils to the interference source for far interference, so the induced electromotive force generated by the interference source in the two receiving coils is basically the same but If the polarity is opposite, they will cancel each other in the receiving coil, and no output signal will be generated, that is, two receiving coils with the same number of turns and reverse polarity connected in series have a canceling effect on distant interference, and the beneficial effect is that it can improve the signal-to-noise Ratio, improve measurement accuracy.
附图说明Description of drawings
图1为现有技术中随钻核磁测井仪探头的结构示意图；Fig. 1 is the structural representation of the probe of the nuclear magnetic logging tool while drilling in the prior art;
图2为收发线圈分离的随钻核磁共振测井仪探头的结构示意图；Fig. 2 is a structural schematic diagram of the probe of the nuclear magnetic resonance logging tool while drilling with separate transceiver coils;
图3为收发线圈分离的随钻核磁共振测井仪探头信号接收的原理示意图；Fig. 3 is a schematic diagram of the principle of signal reception of the probe of the NMR logging tool while the drilling is separated;
图4为收发线圈分离的随钻核磁共振测井仪探头抗干扰的原理示意图。Fig. 4 is a schematic diagram of the anti-interference principle of the probe of the LWD NMR logging tool with separate transceiver coils.
具体实施方式Detailed ways
为了使本发明的目的、技术方案及优点更加清楚明白，以下结合实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.
随钻核磁共振测井仪可以用于垂直井、倾斜井，甚至水平井中。在不同应用中探头姿态是不相同的，因此，探头的“轴向”并不一定是指垂向；但为了说明方便，本实施例以垂直井为例进行阐述，也就是说，在下述实施例中“轴向”设为垂向，但本条设定只为方便实施例阐述并不形成对本发明的限定。While drilling NMR tools can be used in vertical wells, deviated wells, and even horizontal wells. The posture of the probe is different in different applications, therefore, the "axis" of the probe does not necessarily refer to the vertical direction; but for the convenience of explanation, this embodiment takes a vertical well as an example, that is to say, in the following implementation In the example, the "axial direction" is set as vertical, but this setting is only for the convenience of the description of the embodiment and does not form a limitation to the present invention.
本实施例提供了一种收发线圈分离的随钻核磁共振测井仪探头，如图2所示，包括：长圆柱形的探头骨架20，其中探头骨架20包括垂向居中的泥浆通孔21以及与泥浆通孔21同轴的探头外壳22，通过探头外壳22内套入一个内径与泥浆通孔21一致的圆筒实现通孔结构；上下对称设置的第一永磁体23和第二永磁体24，第一永磁体23和第二永磁体24为环形，套设在圆筒上，其中第一永磁体23和第二永磁体24尺寸相同、磁极相对设置，这样放置的上下两个永磁体(23、24)会在敏感区M形成较为均匀的静磁场B0。位于探头中间位置设置发射线圈25，在随钻核磁共振测井仪发射电路的驱动下产生以拉莫尔频率(fL)交变的激发场B1，交变激发场B1的方向与静磁场B0的方向垂直。敏感区M内的流体所含氢核在激发场B1的作用下会吸收能量并进入高能态。接收线圈是由位于发射线圈上部和下部对称安装的两个匝数相同、极性相反(绕制方向相反)的第一接收线圈26和第二接收线圈27组成，第一接收线圈26和第二接收线圈27均与发射线圈同轴，接收线圈的输出是第一接收线圈26和第二接收线圈27串联后的输出。由于发射线圈25位于第一接收线圈26和第二接收线圈27之间，第一接收线圈26和第二接收线圈27在发射线圈25上下呈对称分布，因此，发射线圈25在随钻核磁共振测井仪发射电路的驱动下产生的交变磁场B1在第一接收线圈26和第二接收线圈27中产生的磁通变化是大小相同、方向也相同的。由于两个接收线圈的匝数相同且反极性串联，因此，在发射线圈25发射信号的过程中，两个接收线圈中的磁通变化所产生的感应电动势是大小相同、极性相反的，感应电动势正好对消，即在发射过程中接收线圈不会感应到发射信号。This embodiment provides a kind of NMR logging instrument probe while the transceiver coil is separated, as shown in FIG. The probe housing 22 coaxial with the mud through
激发核磁共振现象产生特定频率的电磁场，这个频率就是拉莫尔频率fL。拉莫尔频率fL的计算公式如下：Exciting the NMR phenomenon produces an electromagnetic field of a specific frequency, which is the Larmor frequency f L . The formula for calculating the Larmor frequency f L is as follows:
式中γ为旋磁比，对于氢核来说，
基于收发线圈分离的随钻核磁测井仪探头进行核磁共振信号接收的过程如图3所示，敏感区M内受到激发的氢核吸收特定频率的电磁能量进入高能态。低能态的氢核就是顺磁状态的氢核、高能态的氢核就是逆磁状态的氢核，顺磁状态的氢核磁极与静磁场B0同向，逆磁状态的氢核磁极与静磁场B0反向。从宏观层面来说激发过程就是产生高能态氢核的过程，由于高能态氢核的出现就形成了一个与静磁场B0反向的磁场B2，B2在弛豫时间内按照特定频率做有规律的上下摆动并逐步衰减变化。这一上下摆动并逐步衰减变化包括两个方面，其一是B2的强度逐渐减小到零，其二是B2的指向与B0的夹角按照一定频率做上下摆动变化，图3中曲线G反应了这一上下摆动并逐步衰减的过程，这一过程也被称为“旋进”。由于B2的旋进在两个接收线圈(26、27)中引起的磁通量变化的极性正好是相反的，也就是说一个接收线圈的磁通量增强，另一个的就减弱，反之亦然。由于两个接收线圈(26、27)采用的是反极性串联结构，所以B2的旋进在两个接收线圈(26、27)中产生的感应电动势是叠加的，也就是说接收线圈输出的电压是两个串联线圈感应电动势求和叠加后的结果。The process of receiving NMR signals by the LWD NMR probe based on the separation of transceiver coils is shown in Figure 3. The excited hydrogen nuclei in the sensitive area M absorb electromagnetic energy of a specific frequency and enter a high-energy state. The hydrogen nuclei in the low-energy state are the hydrogen nuclei in the paramagnetic state, and the hydrogen nuclei in the high-energy state are the hydrogen nuclei in the diamagnetic state. The magnetic field B 0 is reversed. From a macro level, the excitation process is the process of generating high-energy hydrogen nuclei. Due to the appearance of high-energy hydrogen nuclei, a magnetic field B 2 opposite to the static magnetic field B 0 is formed. B 2 acts according to a specific frequency during the relaxation time. Oscillates up and down regularly and gradually decays the change. This swing up and down and gradually attenuation change includes two aspects, one is that the intensity of B 2 gradually decreases to zero, and the other is that the angle between the direction of B 2 and B 0 swings up and down according to a certain frequency, as shown in Figure 3 Curve G reflects this process of swinging up and down and gradually decaying, which is also called "precession". Due to the precession of B2, the polarity of the magnetic flux variation caused in the two receiving coils (26, 27) is just opposite, that is to say, the magnetic flux of one receiving coil increases while that of the other weakens, and vice versa. Since the two receiving coils (26, 27) adopt a reverse polarity series structure, the induced electromotive force generated by the precession of B2 in the two receiving coils (26, 27) is superimposed, that is to say, the output of the receiving coil The voltage is the result of summing the induced electromotive force of two series coils.
收发线圈分离的随钻核磁测井仪探头的远端抗干扰原理如图4所示，设较远距离(一般不低于数米)的干扰源产生的交变的干扰磁场为B3，B3在两个接收线圈(26、27)中引起的磁通量变化的极性是相同的。由于收发线圈分离的随钻核磁测井仪探头的长度在1米左右，两个接收线圈(26、27)的距离很近(一般为分米级)，因此B3到接收线圈(26、27)的距离基本相同，因此可以认为，B3在两个接收线圈(26、27)中引起的磁通量变化的大小基本相同。又因为接收线圈(26、27)反极性串联，所以，B3在两个接收线圈中产生的感应电动势大小基本相同且方向相反，串联后的输出基本相互抵消。The remote anti-jamming principle of the LWD NMR probe with separate transceiver coils is shown in Fig. 4, and the alternating interference magnetic field generated by the interference source at a relatively long distance (generally not less than several meters) is assumed to be B 3 , B 3 The polarity of the magnetic flux change induced in the two receiving coils (26, 27) is the same. Because the length of the probe of the NMR logging tool while the transceiver coil is separated is about 1 meter, the distance between the two receiving coils (26, 27) is very close (generally decimeter level), so B 3 to the receiving coil (26, 27) ) are basically the same distance, so it can be considered that the magnitude of the magnetic flux change caused by B 3 in the two receiving coils (26, 27) is basically the same. And because the receiving coils (26, 27) are connected in series with opposite polarities, the induced electromotive force generated by B 3 in the two receiving coils is basically the same in magnitude and opposite in direction, and the outputs after series connection basically cancel each other out.
本实施例提供的收发线圈分离的随钻核磁测井仪探头，实现收发线圈分离，工程上可以根据发射线圈和接收线圈的需要，分别设计线径、匝数和安装位置等参数，从而优化各自的应用效果；两个匝数相同、反极性串联的接收线圈处在发射线圈轴向的对称位置，在发射过程中接收线圈不会感应到发射信号，使得接收线圈可以在整个测量过程中始终直接与接收放大电路相连，无需具有隔离和切换功能的收发复用电路，不仅简化随钻核磁共振测井仪的整机电路，降低系统复杂度，提高可靠性，而且消除了隔离切换过程对接收电路的影响，提高了探测速度、改善了信号质量；由于两个接收线圈采用的是反极性串联结构，因此敏感区核磁共振现象产生的交变磁场在两个接收线圈中感应出的电动势是叠加的，增强核磁共振信号的接收效果；两个匝数相同、反极性串联的接收线圈对较远的干扰具有对消作用，能够提高信噪比、改善测量精度。The probe of the nuclear magnetic logging tool while drilling with separate transceiver coils provided in this embodiment realizes the separation of transceiver coils. In engineering, parameters such as wire diameter, number of turns, and installation position can be designed separately according to the needs of the transmitter coil and the receiver coil, so as to optimize their respective parameters. The application effect; two receiving coils with the same number of turns and opposite polarity in series are located in the symmetrical position of the transmitting coil axis, and the receiving coil will not sense the transmitting signal during the transmitting process, so that the receiving coil can always be used during the entire measurement process. It is directly connected to the receiving amplifying circuit, without the need for a transceiver multiplexing circuit with isolation and switching functions, which not only simplifies the overall circuit of the NMR logging tool while drilling, reduces system complexity, improves reliability, but also eliminates the impact of the isolation switching process on the receiver. The impact of the circuit improves the detection speed and improves the signal quality; because the two receiving coils adopt a reverse polarity series structure, the electromotive force induced in the two receiving coils by the alternating magnetic field generated by the nuclear magnetic resonance phenomenon in the sensitive area is Superimposed to enhance the receiving effect of nuclear magnetic resonance signals; two receiving coils with the same number of turns and opposite polarity in series have a canceling effect on distant interference, which can increase the signal-to-noise ratio and improve measurement accuracy.
以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.
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Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4785247A (en) * | 1983-06-27 | 1988-11-15 | Nl Industries, Inc. | Drill stem logging with electromagnetic waves and electrostatically-shielded and inductively-coupled transmitter and receiver elements |
| CN1253296A (en) * | 1998-11-05 | 2000-05-17 | 施卢默格控股有限公司 | Equipment and method for obtaining nuclear magnetic resonance measured data during drilling process |
| US6459262B1 (en) * | 2000-04-25 | 2002-10-01 | Baker Hughes Incorporated | Toroidal receiver for NMR MWD |
| US20050030021A1 (en) * | 2003-05-02 | 2005-02-10 | Prammer Manfred G. | Systems and methods for NMR logging |
| CN201671625U (en) * | 2010-05-12 | 2010-12-15 | 中国石油天然气集团公司 | Inductive probe with inductive coil array structure |
| CN103885090A (en) * | 2014-03-28 | 2014-06-25 | 电子科技大学 | Automatic adjusting device and adjusting method for eliminating induction log direct coupling signals |
| WO2016123803A1 (en) * | 2015-02-06 | 2016-08-11 | 美国德州Lh科技有限责任公司 | Antenna circuit for logging, antenna system and corresponding logging method |
| US20160238720A1 (en) * | 2013-12-17 | 2016-08-18 | Halliburton Energy Services, Inc. | Tunable Acoustic Transmitter for Downhole Use |
| CN108474756A (en) * | 2015-12-18 | 2018-08-31 | 斯伦贝谢技术有限公司 | Imaging subsurface formations and features using multi-coil NMR measurements |
| CN110058320A (en) * | 2019-04-28 | 2019-07-26 | 吉林大学 | A kind of adjustable active field nuclear magnetic resonance log probe of detecting area and its detection method |
| CN110199087A (en) * | 2017-03-09 | 2019-09-03 | 哈利伯顿能源服务公司 | With the downhole NMR tool to the dynamic Active Compensation answered that comes into force |
| CN110644970A (en) * | 2019-10-08 | 2020-01-03 | 浙江大学 | A Through-casing Induction Logging Method Based on Lateral Wave Detection |
| CN111796331A (en) * | 2020-08-24 | 2020-10-20 | 吉林大学 | Ground magnetic resonance detection device and method for shallow groundwater and hydrocarbon substances |
| CN112922584A (en) * | 2021-01-21 | 2021-06-08 | 中海油田服务股份有限公司 | Adjacent well detection device, method and system |
| CN113216948A (en) * | 2021-05-19 | 2021-08-06 | 中国石油大学(北京) | Multi-coil-structure while-drilling nuclear magnetic resonance logging device and method |
| CN113655533A (en) * | 2021-08-13 | 2021-11-16 | 核工业二0三研究所 | A sandstone type uranium mine borehole transient electromagnetic logging device and logging method |
Patent Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4785247A (en) * | 1983-06-27 | 1988-11-15 | Nl Industries, Inc. | Drill stem logging with electromagnetic waves and electrostatically-shielded and inductively-coupled transmitter and receiver elements |
| CN1253296A (en) * | 1998-11-05 | 2000-05-17 | 施卢默格控股有限公司 | Equipment and method for obtaining nuclear magnetic resonance measured data during drilling process |
| US6459262B1 (en) * | 2000-04-25 | 2002-10-01 | Baker Hughes Incorporated | Toroidal receiver for NMR MWD |
| US20050030021A1 (en) * | 2003-05-02 | 2005-02-10 | Prammer Manfred G. | Systems and methods for NMR logging |
| CN201671625U (en) * | 2010-05-12 | 2010-12-15 | 中国石油天然气集团公司 | Inductive probe with inductive coil array structure |
| US20160238720A1 (en) * | 2013-12-17 | 2016-08-18 | Halliburton Energy Services, Inc. | Tunable Acoustic Transmitter for Downhole Use |
| CN103885090A (en) * | 2014-03-28 | 2014-06-25 | 电子科技大学 | Automatic adjusting device and adjusting method for eliminating induction log direct coupling signals |
| WO2016123803A1 (en) * | 2015-02-06 | 2016-08-11 | 美国德州Lh科技有限责任公司 | Antenna circuit for logging, antenna system and corresponding logging method |
| CN108474756A (en) * | 2015-12-18 | 2018-08-31 | 斯伦贝谢技术有限公司 | Imaging subsurface formations and features using multi-coil NMR measurements |
| CN110199087A (en) * | 2017-03-09 | 2019-09-03 | 哈利伯顿能源服务公司 | With the downhole NMR tool to the dynamic Active Compensation answered that comes into force |
| CN110058320A (en) * | 2019-04-28 | 2019-07-26 | 吉林大学 | A kind of adjustable active field nuclear magnetic resonance log probe of detecting area and its detection method |
| CN110644970A (en) * | 2019-10-08 | 2020-01-03 | 浙江大学 | A Through-casing Induction Logging Method Based on Lateral Wave Detection |
| CN111796331A (en) * | 2020-08-24 | 2020-10-20 | 吉林大学 | Ground magnetic resonance detection device and method for shallow groundwater and hydrocarbon substances |
| CN112922584A (en) * | 2021-01-21 | 2021-06-08 | 中海油田服务股份有限公司 | Adjacent well detection device, method and system |
| CN113216948A (en) * | 2021-05-19 | 2021-08-06 | 中国石油大学(北京) | Multi-coil-structure while-drilling nuclear magnetic resonance logging device and method |
| CN113655533A (en) * | 2021-08-13 | 2021-11-16 | 核工业二0三研究所 | A sandstone type uranium mine borehole transient electromagnetic logging device and logging method |
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