Views: 777 Author: pqwt Publish Time: 2022-06-06 Origin: PQWT
The bipolar profiles in the ground water detector developed and produced by PQWT are colorful and colorful maps divided by several contour lines. People often ask, what do the different colors represent? Which color represents water? To answer this question you need to start at the beginning.
1. The right side of the profile has a row of color bars (also called value bars), the top is red, from top to bottom in the order of red, orange, yellow, green, green and blue is divided into 18 blocks of color, in each block of color next to the number marked, the number indicates that this color
On behalf of this interval of the value of the potential difference is how much, the uppermost piece of the number marked on behalf of the maximum value of the potential difference is how much, 18 blocks of color will be divided into 17 copies of this maximum value, according to which you can calculate the upper and lower line of the potential difference represented by each block of color. If the maximum value is 2.30, 2.30/17 = 0.14, then the potential difference represented by the bottom dark blue block is
0.00~0.14, and so on for the penultimate block that is 0.14~0.28, the value of each color block is calculated in this way.
2. From the above, it can be seen that the value represented by each color block is determined by the maximum value in the graph. When the same measurement line is repeated, if the maximum value changes due to changes in the strength of the signal source or interference, the value represented by each color block is also adjusted. When the maximum value increases a lot, the color of the other measurement points will change in the direction of blue and appear more blue, even though their values do not change. When the high value is depressed on the computer these measurement points will again change in the direction of red. This shows that the proposition of what color is proposed to represent water is not valid.
3. In the same graph, the color and value indirectly reflect the size of the resistivity of the rock, that is, the difference in the electrical conductivity of the rock. The closer to red, the worse the conductivity, the closer to blue, the better the conductivity. There are many factors that affect the electrical conductivity of rocks, the closer to red
The closer it is to red, the harder the rock, or the better the water quality, or the less conductive minerals, or the smaller the fracture rate, etc., while the closer it is to blue, the opposite is true. In the following we call the change from small to large values in the direction of redness, and vice versa in the direction of blueness. The more factors affecting the electrical conductivity of rocks, the more there are multiple interpretations, which is the multi-solution and complexity of electrical exploration.
4. The category of rocks and mineral composition is very different, and the lithology is different at different depths, so in the chart is neither the redder the better, nor the bluer the better, the principle of finding water is to find the abrupt change in the lateral, from the unchanged, from the small change to the big change, in the reddish blue, in the reddish blue. This is commonly referred to as anomalies, the anomalies described here include both abnormal changes in color, including abnormal changes in the contour, such as abrupt changes in the density of the contour, or jagged, folded, V-shaped, inverted V-shaped and other forms. Observation of anomalies should be mainly horizontal observation, supplemented by vertical observation, the original map 0 gain measured map is the main, supplemented by the processing of the map (retest map can only look at the contour, the color and value can not pay too much attention).
5. Structure can control water, lithology can also control water, brittle hard rocks than soft rocks into a high rate, some people call it lithology control theory. The larger the range of bluish in the graph (also depends on the value of the color block), the greater the possibility of bad lithology, bad lithology fractures are not developed, the water is not good. If the range of blue bias in the red-dominated map is localized, such as a small group of fast, narrow column, or alternating thin layers, the possibility of sudden changes in lithology is much smaller, and the possibility of increased fracture rate is much larger.
6. It is also common to find reddish areas in the blue-dominated map to set the well location. For example, to find gneiss in schist-based rocks, sand conglomerate in mudstone-based rocks, and marble in hornblende-based rocks, is to find red-leaning areas in bluish diagrams. These reddish areas are lithologically good and the fractures will be more developed. In this case, the positive increment of the lithology on the value greatly overshadows the negative increment of the fracture on the value, so it is better to select the reddish area for drilling in this case.
What is the color of the gravel layer of the Quaternary in the upper part of the graph? It depends on whether the underlying Quaternary formation is high or low value. If it is underlain by a very low value mudstone, the sand and gravel layer is reddish, and the sand layer water should be found in a shallow reddish thickness and dark color to set the well. It should be noted that this situation is due to the downward transmission of the high value layer, reflecting the sand layer under the interface may be much larger than the actual depth. This is similar to the situation in a strongly weathered basalt subducted by a thick layer of mudstone.
If the sand and gravel layer is underlain by a high resistance rock, the sand and gravel layer will often be blueish with the weathering zone of the rock and not easily recognizable due to the high porosity of the sand layer containing much water.
8. What does the size of the value of the reddest color block at the top of the color bar tell us? It is an indirect reflection of the resistivity of the rocks, which is positively correlated with each other. The maximum value also becomes larger when the measurement line is close to the high voltage line. The larger the maximum value, the value of each color block are correspondingly larger, even the value of the blue color block will also become larger, so you can not only look at the color of the graph, but also look at the size of its value. The maximum values of a few flying points are caused by disturbances and must be distinguished. The size of the rock resistivity is mainly determined by two aspects of the graph. One is the size of the resistivity of the rock skeleton, mainly related to the mineral composition. The second is the resistivity of the water contained in the voids or fissures of the skeleton size. The less minerals in the water the greater the resistivity, and truly chemically pure water is not conductive. Mountain spring water resistivity is dozens of times greater than the general tap water, plus the mineral composition of the rock, the degree of weathering, differences in electromagnetic interference, so that the maximum value in the profile can be very large in theory, in the absence of interference to reach dozens are normal, the size of the values measured by different manufacturers of instruments are not the same. In the case of Puch there is a maximum value of 222, the water volume is still good, it is very telling, the value is large and there is no direct relationship with the presence or absence of water. In the chert strata because of the hardness of the water, the values are mostly small, mainly also due to the mineral bias in the water or the high fracture rate or even mud seams. It should also be clarified that the value measured by the tensiometer and the potential difference measured by the man-made field are not a concept and are not comparable.
9. What is the reason for the white color in the graph? The white color indicates that the measured value is 0. The color next to the 0 value is usually the dark blue at the bottom of the color bar, and the numbers marked in this dark blue are 0.00~××. It can be assumed that the white color and the dark blue at the bottom are the same color area, and the presence of 0 value is mostly normal. The presence of the white area does not affect other areas, if after retesting 0 value disappears, but still in the dark blue area, is also normal. It is not uncommon for a graph with a 0 value to hit good water, and the size of the water has nothing to do with the 0 value.
10. How to interpret the black diamond-shaped block in the graph? In the profile you will often see some small rhombus or triangle framed in black, and such points on the curve are undoubtedly discrete points with particularly high values. These points can be called flying points because they fly out of the normal range of the curve. The cause of flying points are the result of unexplained interference, often disappear or shift when retesting. Some of the graphs without retesting to such a flying point as the target to hit the water, this is only a coincidence, in the depth of the flying point near the water is very unlikely.
The black edge of the flying point is because its value is too high, and the contour line along its perimeter is very dense, so it becomes black, just like the case of steep hills when drawing the contour line of the terrain is the same. The black horizontal stripes in the figure are also caused by the sudden change in value.
The values of the flying points framed in black do not affect the values and colors of the points outside the black box, so they can be deleted without affecting the analysis of the drawing. However, the figure with more flying points indicates more interference, and most of the star-shaped points without black borders are also caused by interference, and it is worth considering whether the values are reliable.
11. The distribution of blue and red areas up and down in the diagram is also a common diagram type. The upper part of the figure a blue, the thickness is very large, no obvious information, only in the lower part of the red bias, but the depth is larger. This situation does not mean that the upper part must be free of water, just more difficult to analyze. This type of map can be considered from the following three aspects: First, to see the value of the blue area corresponding to the color block, if the value is very small, and no known well information compared to the best to give up another line of measurement. Second, if the value is not very small, and crystalline rocks, you can find relatively high value points from the processing of the map to determine the location of the well, using the weathering layer in the location of the more brittle and hard lithology drilling. Third, if the lower part of the reddish area has anomalies such as the V shape that can withstand verification of the upper and lower penetration, it can be considered as formed by the upper part of the lower transmission, which can also set the well location. In the upper part of the blue area, although there is no direct display, there is a high possibility of water.
Hunan Puqi geological exploration equipment research institute, is engaged in geological survey ground water detector equipment research professional institutions, and undertake the "national thirteenth five-year water special research project" Puqi new generation of physical exploration ground water detector with portable, easy to operate, automatic The equipment has obtained many invention patents and software copyrights.
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