Method for detecting source resistance of controlled source electromagnetic exploration transmission field

Abstract

The present invention discloses a method for detecting the source resistance of a controllable source electromagnetic exploration transmission field, comprising the following steps: performing a screening measurement at the transmitting end and measuring the grounding resistance; if the measured grounding resistance is less than a first preset threshold value, performing a separate symmetrical measurement, first performing an electrode arrangement method to measure the grounding resistance of the emitter plate, and if the grounding resistance of the emitter plate reaches a second preset threshold value, determining the site selection area; then performing a dipole superposition measurement of the resistance, that is, continuing to superimpose the emitter plate measurement resistance, if the monopole reaches below the preset resistance, the production needs are met; and finally completing the measurement of the transmission field source resistance by power-on testing of the transmission system. The present invention can solve the problems of difficult measurement of the transmission field source resistance and low accuracy from the source end of the transmission field, improve the practical problem of quickly and accurately determining whether the transmission field source is qualified and available, improve construction efficiency, reduce production costs, and also reduce floor space, reduce carbon emissions, and reduce environmental pollution.

Description

Technical Field

[0001] The invention belongs to the field of resistivity detection, and in particular relates to a method for rapidly detecting source resistance of a controllable source electromagnetic exploration transmission field. Background Art

[0002] The rapid and accurate measurement of the source resistance of the transmitting field directly restricts and affects the signal-to-noise ratio, resolution and construction progress of the controlled source electromagnetic exploration acquisition signal, and has always been a bottleneck in the field construction of controlled source.

[0003] At present, the existing method for detecting the source resistance of the controllable source electromagnetic exploration launch site is: after the construction launch site source is laid out, the AB launch ends are connected with a launch cable, and the launch system is placed, that is, the resistance is measured at the parking position of the loading vehicle. After meeting the technical requirements, wait for the launch to be in place for the final power-on test, and check the launch site source resistance as the final construction resistance completion record.

[0004] However, this method cannot make a quick judgment at the initial stage of site selection. It needs to wait until all the layout is completed before accurate measurement can be made. If the resistance is too large after measurement and cannot be reduced by limited means, new site selection is required, which is a waste of manpower, material resources and time. In particular, the entire transmitting and receiving unit needs to be stopped until the new site selection meets the requirements before construction can continue. This is also a huge waste of construction resources and greatly restricts the construction progress. Summary of the invention

[0005] The purpose of the present invention is to provide a method for detecting the source resistance of a controllable source electromagnetic exploration transmitting field, so as to solve the problem of poor timeliness of the existing method for measuring the source resistance of a controllable source electromagnetic exploration transmitting field.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for detecting source resistance of a controllable source electromagnetic exploration transmission field comprises the following steps:

[0008] Perform screening measurement on the transmitting end and measure the ground resistance;

[0009] If the measured grounding resistance is less than the first preset threshold, a separate symmetrical measurement is performed: first, the electrode arrangement method is used to measure the emitter plate grounding resistance. If the emitter plate grounding resistance reaches the second preset threshold, the site selection area is determined; then the dipole superposition resistance is measured, that is, the emitter plate measurement resistance is continued to be superimposed. If the single pole reaches below the preset resistance, the production needs are met;

[0010] Finally, the transmission field source resistance measurement is completed through the transmission system power-on test.

[0011] Further, the transmitter screening measurement is performed to measure the ground resistance including:

[0012] Use copper electrodes to connect the test meter in MN mode on site and measure the grounding resistance of the A and B terminals respectively.

[0013] Further, the transmission field source resistance measurement is completed by power-on test of the transmission system, including:

[0014] Carry out power-on measurement of the transmitting system, complete the layout of the field source transmitting end, connect the transmitting cable, connect the laid-out AB field source to the transmitter, and convert the actual working field source resistance through the preset current and emitted voltage.

[0015] Furthermore, the first preset threshold is 1 kΩ.

[0016] Further, the second preset threshold is 300Ω.

[0017] Furthermore, the preset resistance is 10Ω.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0019] The present invention can solve the problem of difficult and low accuracy in measuring the ground resistivity of the launch field source at the source end of the early launch field. It is an effective method for quickly evaluating the preset field source, which improves construction efficiency, reduces production costs, reduces floor space, reduces carbon emissions, and reduces environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flow chart of a method for detecting source resistance of a controlled source electromagnetic exploration transmitting field;

[0021] Figure 2 It is a schematic diagram of the screening measurement at the transmitting end;

[0022] Figure 3 It is a schematic diagram of dipole superposition measurement resistance. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] The present invention relates to a method for detecting the ground resistivity of a controllable source electromagnetic exploration transmitting field source, which solves the problems of slow evaluation and large error of the transmitting field source from the construction source. The method completes the transmitting field source resistance measurement through transmitting end screening measurement, separate symmetrical measurement, and finally completes the transmitting field source resistance measurement through the transmitting system power-on test. It can not only evaluate the transmitting field source performance on site, but also complete the transmitting peripherals more standardized and efficient, including the laying of the transmitting electrode and the transmitting cable, and accurately and quickly measure the real ground resistance of the field source.

[0025] The method for detecting the source resistance of a controllable source electromagnetic exploration transmission field according to an embodiment of the present invention is as follows: Figure 1 As shown, the following steps are included: first, the transmitting end screening measurement is carried out, and the grounding resistance of the A and B ends is measured respectively by using a copper electrode in the MN test meter mode, which is less than 1KΩ; after meeting the requirements, a separate symmetrical measurement is carried out, and the electrode arrangement method is first used to measure the grounding resistance of the emitter plate. If the resistance can reach 300Ω, the site selection area can be basically determined, and then the dipole superposition measurement resistance is carried out, and the emitter plate measurement resistance is continued to be superimposed. When the single pole reaches less than 10Ω, it is determined that it can meet the production needs. Finally, the transmitting system is powered on for measurement. After the field source transmitting end is fully laid out and the transmitting cable is connected, the laid AB field source is connected to the transmitter. Through the preset current and the emitted voltage, the actual working field source resistance is converted to meet the 20Ω or index requirements.

[0026] Specifically:

[0027] (1) Screening measurement of A and B ends

[0028] like Figure 2 As shown, copper electrodes are used to test the meter in MN mode, and the ground resistance of the two transmitting ends is measured respectively, which is less than 1KΩ.

[0029] Connect the MN grounding copper electrode to the test meter and measure the grounding resistance of the A and B terminals respectively. Those less than 1KΩ can generally be used. For 1.1-1.3KΩ, pay attention to the moisture content of the surface soil layer and try to find a surface construction with rich moisture content to increase the suitability of the preset location; for those greater than 2KΩ, basically select another AB position. If there is no suitable A / B position within the 3° angle offset range, you need to contact the designer to adjust the transmitting field source.

[0030] (2) Single symmetric measurement

[0031] ① The electrode arrangement method is used to measure the ground resistance of the emitter plate. If the resistance can reach about 300Ω, the site selection area can be basically determined.

[0032] Drive the P and C grounding nails deep into the ground, and make sure that the grounding nails are driven into the moist soil more than 0.5m below. If the grounding soil is dry, water should be added to moisten it until it is saturated with water. Then, make a straight line with the test emitter plate, and measure the resistance with a resistor. If the resistance reaches 300Ω, the site selection area is determined, and continue to dig a pit to place the aluminum plate.

[0033] ②Dipole superposition measurement resistance

[0034] like Figure 3 As shown, continue to stack the emitter plates to measure the resistance. The single-pole resistance reaches below 10Ω, which is determined to meet production needs.

[0035] (3) Transmitter system power-on measurement

[0036] After the AB field source is fully laid out and the transmitting cable is connected, the laid-out AB field source is connected to the transmitter, and the actual working field source resistance is measured to meet 20Ω or the index requirement.

[0037] In summary, in order to overcome the problems of poor timeliness and low success rate of existing resistance measurement methods, the present invention provides a new multi-field source resistance measurement method for controllable source electromagnetic exploration projects, which can not only quickly determine the approximate layout position of the field source transmitting end, but also more standardized and efficient completion of the transmitting peripherals, including the layout of the emitter and the transmitting cable, and accurately and quickly measure the actual grounding resistance of the field source.

[0038] It will be easily understood by those skilled in the art that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting source resistance of a controllable source electromagnetic exploration transmission field, characterized in that: The following steps are involved: Perform screening measurement on the transmitting end and measure the ground resistance; If the measured grounding resistance is less than the first preset threshold, a separate symmetrical measurement is performed, firstly the emitter plate grounding resistance is measured by the electrode arrangement method, if the emitter plate grounding resistance reaches the second preset threshold, the site selection area is determined; then the dipole superposition resistance is measured, that is, the emitter plate measurement resistance is continued to be superimposed, if the single pole reaches below the preset resistance, the production needs are met; Finally, the transmission field source resistance measurement is completed through the transmission system power-on test; The first preset threshold is 1 kΩ, the second preset threshold is 300 Ω, and the preset resistance is 10 Ω.

2. The method for detecting source resistance of a controllable source electromagnetic exploration transmission field according to claim 1, characterized in that: Perform transmitter screening measurements and measure ground resistance including: Use the MN grounding copper electrode to connect the test meter and measure the grounding resistance of the A and B terminals respectively.

3. The method for detecting source resistance of a controllable source electromagnetic exploration transmission field according to claim 2, characterized in that: The transmitter field source resistance measurement is completed by powering on the transmitter system including: Carry out live measurement of the transmitting system, complete the layout of the transmitting field source, connect the transmitting cable, connect the laid-out AB field source to the transmitter, and convert the actual working field source resistance through the preset current and the emitted voltage.

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