RU2148839C1 - Device for geoelectric reconnaissance - Google Patents

Abstract

FIELD: automatic ground reconnaissance of forced potentials, which are measured with respect to current drop in grounded feeding line. SUBSTANCE: device has generator of rectangular current pulses. Output of generator is connected through current detector to grounding electrodes. In addition device has meter, which is connected to current detector, computer and satellite receiver. Outputs of meter and satellite receiver are connected to computer. Grounding electrodes may be designed as tractor caterpillars. EFFECT: mobile automatic process with synchronous satellite topological mapping of locations and routes of measurements. 2 dwg

Description

 The invention relates to terrestrial electrical exploration by the method of induced polarization.

 The proposed device for geoelectrical exploration has no foreign analogues. From domestic, the closest analogue of the claimed invention is a device for implementing a method for measuring the parameters of induced polarization by current decay in an earthed supply line, comprising a rectangular current pulse generator connected in series with a current sensor and electrodes; meter connected to a current sensor. Moreover, non-polarizing electrodes and the use of a potential electrical prospecting installation (SU 1104455 A, class G 01 V 3/08. Publish. 07.23.84, bull. N 27) are provided in the device diagram.

 The above characteristics of the analogue, with the exception of the design of the electrodes and electrical installation, coincide with the essential features of the claimed invention. However, they are insufficient to obtain the required technical result — expanding the arsenal of more advanced productive and cost-effective automated technical means for geoelectrical exploration of the ore direction, and in particular, to solve the problem of creating a device that allows for the first time to carry out high-performance, automated ground-based continuous shooting of evoked potentials using pulsed current in motion with simultaneous synchronous satellite topographic location of points and measurement routes. The reasons that impede the receipt of the required technical result with a known device are as follows. The device’s circuit does not contain technical elements with certain connections, without which it is impossible to automate and synchronize continuous processes of measuring geophysical and navigation parameters in motion, and the non-polarizable electrodes provided in the circuit do not provide good motion that does not change much over time with the surface layer of the earth. In addition, the analogue lacks a mechanical draft element (for example, tracked vehicles), which is necessary to increase the measurement performance by increasing the speed of movement of the electrical prospecting installation; also in the analogue circuit, a potential electrical exploration installation is used in which "one grounding of the line moves along the profile ..., the second grounding ... remains stationary". Depending on the speed of movement of one of the electrodes, both the number of turns of the wire of the supply line on the unwinding (reeling) coil and the length of this line vary unevenly. The electrodynamic disturbances arising in this case, which are difficult to take into account (induction, capacitive), distorting the measured VP parameters, limit the use of such an electrical prospecting installation. The proposed device employs an electrical exploration installation in which both electrodes move at a fixed distance from each other, without using a coil, which significantly reduces the influence of electrodynamic effects on the accuracy of measurements of VP parameters in motion.

 The purpose of the invention is to obtain the above technical result by eliminating the reasons that impede its receipt.

 The essence of the proposed device for geoelectrical exploration, which implements a method of measuring induced polarization by a decrease in current in an earthed supply line, passed in the mode of short (tens of milliseconds) unipolar periodic rectangular pulses, is that it includes a combination of the following, in a certain way interconnected technical elements (Fig. 1): a rectangular pulse current generator 1, the output of which is connected via a current sensor 2 to the ground electrodes 3; meter 4 connected to a current sensor; satellite receiver 5 and computer 6, and the outputs of the meter and satellite receiver are connected to the computer, and vehicle tracks were used as ground electrodes.

 Distinctive features from the closest analogue are new technical elements (computers, satellite receiver), their relationship between themselves and the meter, as well as the linear shape and design of the ground electrodes in the form of vehicle tracks.

 Currently, in regional geophysical operations of the ore direction, surface electrical prospecting using the VP method, which is the most effective in assessing the ore content of territories, is practically not used. The main reason limiting the use of the VP method at this stage of work when using traditional devices that do not provide automation and time synchronization of the processes of ground surveying of VP and navigation support is their low productivity and high cost. The most significant positive technical and economic effect is expected to be obtained by using the proposed device for geoelectro-prospecting in regional geophysical ore operations, designed to provide small-, medium-scale state geological surveys (GHS) and geological exploration of areas (GDP). Using the proposed device for geoelectrical exploration is expected to increase productivity and profitability of not only small, medium, but also large-scale ground and water surveys using the VP method.

 In FIG. 1 shows a diagram of a device; in FIG. 2 is a map of induced polarization obtained with a device in one of the ore deposits of East Transbaikalia.

 Information confirming the possibility of implementing a device for geoelectrical exploration.

 The experimental layout of the device for geoelectrical exploration in its design has the following necessary and sufficient technical elements and communications (Fig. 1): a rectangular current pulse generator 1, the output of which is connected through a current sensor 2 to ground electrodes 3; a meter 4 connected to a current sensor, a computer 6 and a satellite receiver 5, and the outputs of the meter and satellite receiver are connected to a computer. To improve the contacts of grounding electrodes with the surface layer of the earth, which is necessary to lower the level and dispersion of transition resistance, increase useful signals and measurement accuracy, tracks of vehicles (all-terrain vehicles, tractors) were used as grounding electrodes.

 The experimental layout of the device for geoelectrical exploration works as follows. From the DC source (from the battery pack), a constant voltage is applied to the input of the generator 1, which is converted by the generator into rectangular signals with a duty cycle of 2 and a pulse duration of 12.8 ms. Such a conversion is carried out by supplying a clock signal generated by the meter 4, on the electronic key of the generator. Polarizing current pulses coming from the output of this generator are supplied to the ground electrodes 3 through a current sensor 2, represented by a low-resistance (several tens of ohms) measuring resistor, from the terminals of which the signals recorded by the meter 4 are removed.

 The meter, represented by a computerized design device ZabNII "Chara-3", allows you to calculate and store in your electronic memory measured in a time interval (from 0.1 to 12.8 ms) from the measured signal accumulated over 1-1.5 s VP parameters (UPR, hk, Sk, R, where UPR is the potential of the current transmitted in the pulse, hk is the apparent polarizability, Sk is the apparent decay rate of the VP, R is the transition resistance of the ground electrodes) and the measurement time. The accumulated data is transmitted to the on-board computer 6. Synchronously with the registration of the parameters of the induced polarization in the automatic mode, satellite topographic locations of the points and routes of these measurements are carried out using a satellite receiver 5. The digital code transmitted by three to six satellites is received by a compact antenna located on the roof of one of the two tracked vehicles, and fed to the input of a satellite receiver, which calculates the coordinates and transmits them to the on-board computer every 2 seconds. Vehicles whose tracks serve as ground electrode 3 are spaced apart from each other, depending on the required depth of study.

 Using the software, the obtained data are processed on the on-board computer, and within 15-30 minutes the resulting documents are obtained in the form of topographically linked contour plans and graphs of the measured airspace parameters.

 As an example, confirming the operability of the inventive device for geoelectrical exploration, in FIG. Figure 2 shows the results of testing a prototype of this device for medium-sized ground-based surveys of induced polarization due to current decay in motion with the simultaneous automated process of topographic location of measurement routes along a network of roads in the area of the Kruchininsky titanium-magnetite deposit in East Transbaikalia. The deposit is represented by a gabbro-pyroxenite complex with abundant impregnation of titanium-magnetite containing massive apatite-titanium-magnetite ores.

 When shooting VP ST, the tracks of two tractors moving one after another at a distance of 30 m at a speed of 5 km / h were used as grounding electrodes. As can be seen from FIG. 2, the explored sections of the concentration of disseminated and massive ores (N 1 and N 2) are recorded by intense (more than 20%) VP anomalies.

Claims (1)

 A device for geoelectrical exploration, which implements a method of measuring the parameters of induced polarization by a decrease in current in a grounded supply line and contains a rectangular current pulse generator, the output of which is connected to ground electrodes through a current sensor, a meter connected to a current sensor, characterized in that the device further comprises A computer and a satellite receiver, and the outputs of the meter and satellite receiver are connected to the computer, and transport medium tracks were used as ground electrodes d STV.

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