CN106646624B - Asymmetric electrical method sounding method - Google Patents

Abstract

In the asymmetric electrical sounding method, the present invention designs a series of equidistant power supply points that are only symmetrical to a certain fixed point, and utilizes the electrical survey transmitter to supply power underground through two symmetrical power supply points relative to the fixed point. The electrical prospecting receiver is used to simultaneously receive the electric field signals on all the measuring points of the prospecting line, and obtain the apparent resistivity and induced electrical parameters of each measuring point when each pair of symmetrical power supply points is powered. The present invention greatly reduces the workload of arranging power supply points, and can realize multi-channel electrical instruments or multiple electrical instruments to carry out sounding for multiple sounding points at the same time, thereby improving the exploration efficiency of two-dimensional or three-dimensional electrical sounding . In the 3D asymmetrical electrical sounding mode, due to the use of the 3D electrical sounding mode, both the exploration efficiency and the exploration effect can be improved.

Description

Asymmetric electrical sounding method

technical field

The invention relates to an electrical sounding method in the field of geophysics.

Background technique

At present, there are symmetrical quadrupole sounding, dipole-dipole sounding and middle ladder profile sounding in two-dimensional electrical prospecting.

The symmetrical quadrupole sounding method uses approximately logarithmically equidistant power supply distances at each measurement point to realize two-dimensional electrical survey sounding. The advantage of this method is that each measurement point is arranged with a symmetrical power supply electrode relative to the measurement point. The measurement electrode distance is controlled to be less than 1/3 of the power supply electrode distance, so that the measurement signal at the measurement point presents a horizontal field trend, and the geological interpretation is simple. However, since each measurement point needs to arrange a series of power supply points, each arrangement of a series of power supply points can only measure a single measurement point, so the work efficiency is too low. Assuming that n symmetrical quadrupole measuring points are arranged on a certain exploration line, according to the layout of the supply electrode distance and measuring electrode distance parameter table of a single symmetrical quadrupole measuring point shown in Table 1, in order to complete the sounding work of all measuring points, it is necessary to arrange 16×2×n power supply points, the workload is too large, so in the actual exploration work, the number of symmetrical quadrupole measurement points will be reduced as much as possible to reduce the exploration cost, but it will lead to a decrease in the exploration effect.

Table 1 Parameter table of the distance between the supply electrode and the distance between the measuring electrodes of a single measurement point of symmetrical quadrupole

The dipole-dipole sounding method adopts short power supply electrode distance and measuring pole distance, which can realize high efficiency of electric sounding. In order to achieve deep sounding, the interval coefficient is increased. With the increase of the interval coefficient, the electric field signal attenuates quickly. In order to achieve a greater exploration depth, it can only be realized by increasing the power of the power supply system, which will lead to The power supply system is bulky, which reduces the exploration efficiency.

The middle-ladder section sounding method borrows the middle-ladder profile mode, and achieves the purpose of sounding by changing the size of the middle-ladder power supply electrode distance. However, this method uses a symmetrical quadrupole with a small pole pitch to measure the electrical signal of each measurement point for the sounding work of the power supply point within the range of the measurement point, which results in the need to carry out two measurements for each measurement point. Although this method of electrical prospecting can reduce the workload of sounding with large pole distance, it increases the workload of small pole distance.

Contents of the invention

The purpose of the present invention is to design a series of equally spaced power supply points that are only symmetrical with respect to a certain fixed point, and use the electrical survey transmitter to supply power to the ground through two power supply points that are symmetrical with respect to the fixed point, and use the electrical survey to receive power. The machine simultaneously receives the electric field signals on all the measurement points of the exploration line, obtains the apparent resistivity, induced electricity and other parameters of each measurement point when each pair of symmetrical power supply points supplies power, reduces the number of times of moving the power supply points of the electric sounding method, and realizes the All measurement points carry out asymmetric electrical sounding to improve the efficiency and effect of electrical exploration.

Based on the deficiencies of methods such as symmetrical quadrupole and middle ladder profile sounding, the asymmetric electrical sounding method proposed by the present invention arranges a series of symmetrical The equidistant symmetrical power supply points at the middle position carry out the asymmetric electrical sounding survey for all the measuring points of the survey line at the same time.

The concrete steps of this method are:

(1) Analyze the previous geological results of the exploration area in advance, infer the distribution of major geological anomalies in the area, and set the direction of the exploration line for asymmetrical electrical sounding;

(2) According to the exploration requirements, determine the length and number of exploration lines, and determine the exploration area parameters (m, n, t) according to the corresponding spacing, where m is the number of measurement points for each exploration line, and n is the number of power supply points , t is the number of exploration lines;

(3) Based on the characteristics of the exploration target and the topography and relief characteristics of the exploration area, the coordinate arrangement rules of the measurement points and power supply points of the asymmetrical electrical sounding method are adopted to determine the coordinates of all measurement points and power supply points, and arrange the measurement points and power supply point;

(4) Select two power supply points that are symmetrical relative to the origin of the coordinates each time and use the electrical survey transmitter to supply power. All the electrical data measurement points on the survey line use the electrical survey receiver for electrical data collection. Electrical data of all electrical data measurement points during the first power supply;

(5) Then change the positions of the two power supply points that are symmetrical relative to the origin of the coordinates to ensure that the relationship between the two power supply points is still symmetrical relative to the origin of the coordinates, repeat the above tasks of power supply and data collection, and obtain the asymmetric electrical method of the entire exploration area bathymetric data;

(6) Combine the above data into asymmetric electrical sounding data, use electrical exploration data processing and interpretation software for subsequent data processing and interpretation, and obtain asymmetric electrical sounding results of the entire exploration area.

The rules for determining the exploration area parameters (m, n, t) in the step (2) of the asymmetric electrical sounding method proposed by the present invention are divided into two cases: the first case is, two-dimensional asymmetric electrical sounding ; The second case is three-dimensional asymmetric electrical sounding.

A) If two-dimensional asymmetric electrical sounding is carried out, it is assumed that the direction of a certain two-dimensional asymmetric electrical sounding exploration line in the exploration area is the X direction, where the X direction is the horizontal direction; the length of the exploration line is L, and each measurement The distance between points is a, and the maximum exploration depth is h, then the number of measurement points m of this exploration line is

The number of power supply points n is

The number of exploration lines t=1.

B) If three-dimensional asymmetric electrical prospecting is carried out, the direction of the three-dimensional asymmetric electrical prospecting line in the exploration area is the X direction, the length of the X-direction prospecting line is L, and the total distance between the Y-direction prospecting lines is Q, where the X-direction and the Y-direction vertical, and both are horizontal; the interval of each measurement point is a, the interval of exploration lines is b, and the maximum exploration depth is h, then the number of measurement points m of each exploration line is

The number n of power supply points is:

The number t of exploration lines in the entire exploration area is:

In the step (3) of the asymmetric electrical sounding method proposed by the present invention, the measuring point and the power supply point coordinate layout rules of the asymmetric electrical sounding method are also divided into two cases: the first case is that the two-dimensional asymmetric Electric sounding; the second case is three-dimensional asymmetric electric sounding.

A) If the two-dimensional asymmetric electrical sounding method is carried out, the coordinates of the measuring point x _pi , the coordinates of the power supply point of the A pole x _Ai , and the coordinates of the power supply point of the B pole x _Bi are arranged as follows:

Select the middle position of the exploration line as the coordinate origin, then the coordinates x _pi of all electrical data measurement points of the two-dimensional asymmetric electrical sounding are:

The coordinates of all two-dimensional asymmetric electrical sounding power supply points on the survey line are divided into two cases. If the power supply point of pole A is arranged in the negative direction of X, and the power supply point of pole B is arranged in the positive direction of X, then the coordinates of the power supply point of pole A are x _Ai is:

The coordinate x _Bi of the B pole power supply point is:

B) If the three-dimensional asymmetric electrical sounding method is carried out, the coordinates of the measuring point (x _pi , y _pj ), the coordinates of the power supply point of the A pole (x _Ai , y _Ai ), the coordinates of the power supply point of the B pole (x _Bi , y _Bi ) layout rules are as follows:

Select the center point of the exploration rectangular area as the coordinate origin, then the coordinates (x _pi , y _pj ) of all electrical data measurement points of the 3D asymmetric electrical sounding are:

The coordinates of all three-dimensional asymmetric electrical sounding power supply points in this exploration area are divided into two cases. If the negative direction of X is set as the power supply point of pole A, and the positive direction of X is the power supply point of pole B, then the coordinates of the power supply point of pole A (x _Ai ,y _Ai ) is:

Then the coordinates (x _Bi , y _Bi ) of the B pole power supply point are:

The electrical data measuring device in this method can be carried out by using a monopole or a dipole measuring device, so it can be subdivided into: two-dimensional or three-dimensional asymmetrical electrical sounding monopole or dipole measuring device.

The method proposed by the invention only needs to arrange a series of symmetrical power supply points relative to a fixed point, the distance between the power supply points is equal to the distance between the measurement points, and each time a pair of symmetrical power supply electrodes is supplied with power, while all the measurement points on all the survey lines are collected at the same time Since the electric field signal of the electric field signal is only symmetrical to a certain fixed point, it is not necessarily symmetrical to the measurement point, so this method is named as the asymmetric electric sounding method.

Since the above-mentioned asymmetrical electrical sounding method does not need to arrange a series of power supply points symmetrical to each measurement point like the symmetrical quadrupole sounding method, nor does it need to arrange the middle ladder sounding outside the measuring point like the middle ladder profile sounding method The symmetrical quadrupole sounding with small pole spacing is also arranged within the scope of the measurement points, so the method proposed by the present invention greatly reduces the workload of arranging power supply points, thereby improving the efficiency of two-dimensional or three-dimensional electrical exploration. In the 3D asymmetrical electrical sounding mode, due to the use of the 3D electrical sounding mode, both the exploration efficiency and the exploration effect can be improved.

Description of drawings

Figure 1 is a diagram of a two-dimensional asymmetric electrical prospecting monopole measurement device;

Fig. 2 is a diagram of a three-dimensional asymmetric electrical prospecting monopole measurement device;

Fig. 3 is a diagram of a two-dimensional asymmetric electrical prospecting dipole measurement device;

Fig. 4 is a diagram of a three-dimensional asymmetric electrical prospecting dipole measurement device.

Detailed ways

The present invention will be further described below in conjunction with Fig. 1, Fig. 2 and embodiments.

The power supply system and the electrical data measurement system of the method are fully compatible with existing electrical exploration equipment, and the electrical data measurement system can adopt a multi-channel electrical data measurement system or multiple sets of electrical data measurement systems.

Example 1

1 in the figure is the electrical prospecting transmitter, 2 is the A pole power supply line, 3 is the B pole power supply line, the circular symbol 4 refers to the electric field signal measurement electrode point, and the hollow cross symbol 5 refers to the A pole The power supply point, the solid cross symbol indicated by 6 is the B pole power supply point, 7 is the electric field signal measurement wire, 8 is the electrical prospecting receiver, 9 is the electric field signal infinity measurement wire and electrode, A and the dashed arrow indicate the A pole The direction of the pole running of the power supply point, B and the dotted arrow indicate the direction of the pole running of the power supply point of the B pole.

The specific implementation of the method is divided into two cases of a two-dimensional asymmetric electric sounding monopole measuring device and a three-dimensional asymmetric electric sounding monopole measuring device for description respectively.

1. In the first case, the implementation mode of the two-dimensional asymmetric electrical sounding monopole measurement device

1) Based on the exploration requirements, select the X direction and length L of an exploration line that needs to carry out two-dimensional electrical exploration, the distance between measurement points a, and the maximum exploration depth h, according to the formula (1)

Determine the number m of two-dimensional asymmetric electrical sounding measurement points;

2) According to formula (2)

Determine the number n of all power supply points in the two-dimensional asymmetric electrical prospecting of the prospecting line;

3) According to formula (3)

Determine the coordinates x _pi of all measurement points of the two-dimensional asymmetric electrical prospecting of the prospecting line;

4) According to formulas (4) and (5)

Determine the coordinates x Ai of the coordinates x _Ai of the power supply points of the A pole and the coordinates x _Bi of the power supply point of the B pole of the two-dimensional asymmetric electrical exploration of the survey line;

5) Determine and arrange power supply points and measurement points on the field exploration line according to all the parameters obtained above;

6) Arrange the electrical survey transmitter 1 according to Figure 1; arrange the A pole power supply line 2 and connect it with the A pole power supply point 5 (A1 as shown in Figure 1); arrange the B pole power supply line 3 and connect it with The B pole power supply point 6 (B1 as shown in Figure 1) is connected; All measurement electrode points 4 are connected with the electrical method prospecting receiver 8 through the wire 7; Exploration receiver 8 is connected;

7) The electrical survey transmitter 1 is powered by two electrodes of the A pole power supply point 5 (A1 as shown in FIG. 1 ) and the B pole power supply point 6 (B1 as shown in FIG. 1 );

8) The electrical prospecting receiver 8 performs electrical data measurement on all measuring electrode points 4, and obtains corresponding asymmetric two-dimensional electrical prospecting data;

9) Move the A pole power supply line 2 and A pole power supply point 5, B pole power supply line 3 and B pole power supply point 6, and the two power supply points and wires to other positions (A2 and B2 as shown in Figure 1), repeat step 8 Step until the positions of the two power supply points of the A pole power supply point 5 and the B pole power supply point 6 reach the positions of the An/2 and Bn/2 power supply points, so as to obtain the two-dimensional asymmetric electrical sounding data of the entire survey line;

10) Perform data processing and interpretation on all the above two-dimensional asymmetric electrical sounding data, and obtain the two-dimensional asymmetric electrical sounding results of the entire exploration line.

If L=400 meters in the above-mentioned specific embodiment, a=40 meters, h=300 meters, then measuring point m=11, power supply point number n=40, can determine two-dimensional asymmetric electric method sounding A, B The coordinate parameter table of the supply electrode and the coordinate parameter table of the two-dimensional asymmetric electrical bathymetry measurement electrode are shown in Tables 2 and 3 below, respectively. In order to complete the sounding work of the 11 measurement points of the above-mentioned exploration line, 40 (20 pairs) symmetrical power supply points need to be arranged, and the farthest AB length is 1560 meters.

Table 2 Two-dimensional asymmetric electrical sounding A, B supply electrode coordinate parameter table

Table 3. Two-dimensional asymmetric electrical bathymetry electrode coordinate parameter list

serial number Measuring Electrode Coordinates 1 -200 2 -160 3 -120 4 -80 5 -40 6 0 7 40 8 80 9 120 10 160 11 200

2. In the second case, the implementation mode of the three-dimensional asymmetric electrical sounding monopole measurement device:

1) Based on the exploration requirements, select the X and Y directions and the corresponding lengths L and Q of the exploration area that needs to carry out three-dimensional electrical prospecting;

2) Determine the measurement point interval a, the exploration line interval b, and the maximum exploration depth h in the exploration area, according to the formula (6)

Determine the number of measuring points m for each exploration line of the three-dimensional asymmetric electrical sounding;

3) According to formula (7)

Determine the number n of three-dimensional asymmetric electrical sounding power supply points;

4) According to formula (8)

Determine the number t of three-dimensional asymmetric electrical sounding exploration lines;

5) According to formula (9)

Determine the coordinates (x _pi , y _pj ) of all measurement points of the three-dimensional asymmetric electrical sounding in the exploration area;

6) According to formulas (10) and (11)

Determine the coordinates of the A pole power supply point (x _Ai , y _Ai ) and the B pole power supply point (x _Bi , y _Bi ) coordinates of all three-dimensional asymmetric electrical sounding in the exploration area;

7) Determine and arrange power supply points and measurement points in the exploration area according to all the parameters obtained above;

8) Arrange the electrical survey transmitter 1 according to Figure 2; arrange the A pole power supply line 2 and connect it with the A pole power supply point 5 (A1 shown in Figure 2); arrange the B pole power supply line 3 and connect it with The B pole power supply point 6 (B1 as shown in Figure 2) is connected; All measurement electrode points 4 are connected with the electrical method prospecting receiver 8 through the wire 7; Exploration receiver 8 is connected;

9) The electrical survey transmitter 1 is powered by two electrodes of the A pole power supply point 5 (A1 as shown in FIG. 2 ) and the B pole power supply point 6 (B1 as shown in FIG. 2 );

10) The electrical prospecting receiver 8 performs electrical data measurement on all measuring electrode points 4, and obtains corresponding asymmetric three-dimensional electrical prospecting data;

11) Move the A pole power supply line 2 and A pole power supply point 5, B pole power supply line 3 and B pole power supply point 6, two power supply points and wires to other positions (A ₂ and B ₂ as shown in Figure 2), repeat Step 8, until the positions of the two power supply points of A pole power supply point 5 and B pole power supply point 6 reach the positions of A _n/2 and B _n/2 power supply points, so as to obtain the three-dimensional asymmetric electrical sounding data of the entire exploration area ;

12) Perform data processing and interpretation on all the above three-dimensional asymmetric electrical sounding data, and obtain the three-dimensional asymmetric electrical sounding results of the entire exploration area.

Exploration Efficiency Comparison Experiment

In order to compare the exploration efficiency of two-dimensional asymmetrical electrical sounding and symmetrical quadrupole sounding, it is assumed that there is a 400-meter-long exploration line in an exploration area that needs to be carried out by two-dimensional electrical sounding, the distance between measurement points is 40 meters, and the maximum exploration depth is 300 meters. According to the above requirements, a total of 11 measurement points need to carry out two-dimensional electrical sounding.

If symmetric quadrupole sounding is carried out for 11 measurement points, according to the parameter table of the power supply electrode distance and the measurement electrode distance of the symmetrical quadrupole measurement points shown in Table 1, each measurement point needs to arrange 15 pairs of symmetry relative to each measurement point Power supply points, 11 measurement points need to arrange a total of 165 pairs of power supply points.

However, if two-dimensional asymmetric electrical sounding is carried out for the 11 measurement points, according to the two-dimensional asymmetric electrical sounding A and B electrode coordinate parameter tables shown in Table 2 and the two-dimensional asymmetric electrical sounding shown in Table 3 According to the parameters provided in the electrode coordinate parameter table for electrical sounding measurement, only 20 pairs (40) of two-dimensional asymmetric electrical sounding power supply points symmetrical to the middle point of the exploration line are arranged at 11 measurement points, and 11 measurements can be completed Point two-dimensional asymmetric electrical sounding.

Comparing the number of power supply points laid out by the above two methods, it can be found that the workload of laying out power supply points by the two-dimensional asymmetrical electrical sounding method is significantly less than that of the symmetrical quadrupole electrical sounding method, so the exploration efficiency of the former is higher than that of the latter.

Since the two-dimensional asymmetrical electrical sounding conducts electrical data collection on 11 measurement points at the same time, multi-channel or multiple sets of electrical receivers can be used to simultaneously collect data from multiple measurement points in order to improve the overall exploration efficiency . However, the symmetrical quadrupole sounding can only carry out electrical data acquisition for one measurement point at a time, so it cannot use multi-channel or multiple sets of electrical receivers, so its exploration efficiency is low.

If there are multiple parallel exploration lines in the exploration area that need to carry out two-dimensional electric sounding, if three-dimensional asymmetric electric sounding can be carried out, the improvement of exploration efficiency will be more obvious than that of symmetrical quadrupole electric sounding. And because the three-dimensional electrical prospecting is used, its prospecting effect is better than the two-dimensional results of the symmetrical quadrupole electric sounding.

Claims (3)

1. asymmetric electrical method sounding method, it is characterised in that：It is symmetrically a series of etc. only with respect to a certain fixed point by design Spacing supply terminals using electrical prospecting transmitter by powering relative to symmetrical two supply terminals of the fixed point to underground, is adopted The electric field signal in all measurement points of exploration line is received simultaneously with electrical prospecting receiver, asks for every a pair of of symmetrical powering point power supply When each measurement point apparent resistivity and parameters of electrical induction, realize and asymmetric electrical method depth measurement carried out to all measurement points simultaneously；Specifically Step is：

(1) Geological Achievements early period of look-ahead analysis exploration area, infer the distribution situation of main geologic anomalous body in area, and setting is non-right Claim the exploration line direction of electrical method depth measurement；

(2) required according to exploration, determine the length and quantity of exploration line, and according to corresponding spacing, determine exploration area parameter (m, n、t)；Wherein, m is the measurement point quantity of every exploration line, and n is supply terminals quantity, and t is exploration line quantity；

(3) the exploration targets body characteristics based on exploration area, topography and geomorphology relief feature, using the measurement point of asymmetric electrical method depth measurement With power supply point coordinates layout rules, the coordinate of all measurement points and supply terminals is determined, and arrange measurement point and supply terminals；

(4) selection is powered relative to symmetrical two supply terminals of coordinate origin using electrical prospecting transmitter every time, is owned Electrical method data measurement points in exploration line carry out electrical method data acquisition using electrical prospecting receiver, when getting each power supply The electrical method data of all electrical method data measurement points；

(5) then change relative to symmetrical two supply terminals of coordinate origin position, ensure two supply terminals still in relation to Coordinate origin is symmetrical, repeats above power supply and data acquisition, gets the asymmetric electrical method depth measurement data of entire exploration area；

(6) above-mentioned data are combined as Asymmetric Electric method depth measurement data, using electrical prospecting data process and interpretation software, carried out Follow-up data processing and analysis obtain the asymmetric electrical method depth measurement achievement of entire exploration area.

2. asymmetric electrical method sounding method as described in claim 1, it is characterised in that：The step of asymmetric electrical method sounding method (2) rule of determining exploration area parameter (m, n, t) is in：

When A) carrying out two-dimentional asymmetric electrical method depth measurement, then the asymmetric electrical method depth measurement exploration line direction of exploration area two dimension is set as X Direction, wherein X-direction are horizontal direction；Exploration line length is L, and each interval of measuring points distance is a, and maximum depth of exploration is h, Then the measurement point quantity m of the exploration line is

Supply terminals quantity n is

Exploration line quantity t=1；

When B) carrying out three-dimensional asymmetric electrical prospecting, then exploration area three-dimensional asymmetric electrical prospecting line direction is set as X-direction, X side It is L to exploration line length, the total spacing of Y-direction exploration line is Q, and wherein X-direction is vertical with Y-direction, and is horizontal direction；Each Interval of measuring points distance is a, and exploration line spacing is b, and maximum depth of exploration is the measurement point quantity of h, then every exploration line of X-direction M is

Supply terminals quantity n is：

Entirely exploration area exploration line quantity t is：

3. asymmetric electrical method sounding method as claimed in claim 2, it is characterised in that：The step of asymmetric electrical method sounding method (3) using the measurement point of asymmetric electrical method depth measurement and power supply point coordinates layout rules in：

When A) carrying out two-dimentional asymmetric electrical method sounding method, then it measures point coordinates x_piWith A poles power supply point coordinates x_Ai, B poles power supply Point coordinates x_BiLayout rules are as follows：The centre position for choosing the exploration line is coordinate origin, then two-dimentional asymmetric electrical method depth measurement institute There is the coordinate x of electrical method data measurement points_piFor：

The wherein integer (6) of i ∈ [1, m]

The coordinate of the asymmetric electrical method depth measurement supply terminals of all two dimensions of the exploration line is divided into two kinds of situations, setting X negative direction arrangement A poles Supply terminals, X positive directions arrange B poles supply terminals, then the coordinate x of A poles supply terminals_AiFor：

The wherein integer (7) of i ∈ [1, n/2]

The coordinate x of B poles supply terminals_BiFor：

The wherein integer (8) of i ∈ [1, n/2]

When B) carrying out three-dimensional asymmetric electrical method sounding method, then it measures point coordinates (x_pi,y_pj) and A poles power supply point coordinates (x_Ai, y_Ai), B poles power supply point coordinates (x_Bi,y_Bi) layout rules are as follows：The center of the exploration rectangle region is chosen as coordinate origin, three Tie up the coordinate (x of all electrical method data measurement points of asymmetric electrical method depth measurement_pi,y_pj) be：

The wherein integer of i ∈ [1, m], the integer (9) of j ∈ [1, t]

The coordinate of all three-dimensional asymmetric electrical method depth measurement supply terminals in the exploration area is divided into two kinds of situations, sets X negative directions and is supplied as A poles Electric, X positive directions are the coordinate (x of B poles supply terminals, then A poles supply terminals_Ai,y_Ai) be：

The wherein integer (10) of i ∈ [1, n/2]

Then coordinate (the x of B poles supply terminals_Bi,y_Bi) be：

The wherein integer (11) of i ∈ [1, n/2].