A method for detecting the natural potential of well water source for earthquake water level observation

Abstract

The invention relates to a method for detecting the natural potential in a well for detecting the water source of a seismic water level observation well, comprising: S1, collecting the potential value measured by a zero potential electrode; S3, adjusting the spacing between non-polarized electrodes in a measuring cable; S4, gradually lowering the measuring cable from the wellhead of the observation well until the non-polarized electrode at the bottom of the measuring cable is lowered to the bottom of the well, and in the process of lowering the measuring cable, a collector collects the potential value measured by each non-polarized electrode in the measuring cable according to a preset collection interval, and sends the potential value measured by each non-polarized electrode to a notebook terminal; S4, obtaining the natural potential value of each non-polarized electrode according to the potential value measured by each non-polarized electrode and the potential value measured by the zero potential electrode, and drawing the curve of the natural potential values ​​of four non-polarized electrodes in real time; S5, determining the layer that exchanges water with the outside world based on the natural potential value curves of the four non-polarized electrodes.

Description

Technical Field

[0001] The present invention relates to the technical field of seismic activity monitoring, and in particular to a natural potential method in a well for detecting the source of water in a seismic water level observation well. Background Art

[0002] There are some problems in the static water level observation of earthquake monitoring that are difficult to solve, which are reflected in four aspects:

[0003] 1. It is difficult to fully seal the casing of seismic fluid monitoring. Water from the outside can easily seep into the wellbore to form water exchange, causing the static water level to rise or fall or abnormal water temperature changes.

[0004] 2. Seismic fluid observation wells are easily affected by heavy rainfall, but the impact status is difficult to quantify directly using rainfall. It generally shows different degrees of lag effect, and there are cases where rainfall loading is incorrect and untimely.

[0005] 3. Industrial pumping construction near the static water level observation well may cause the water level of the high-pressure aquifer to drop sharply during the water inrush process.

[0006] 4. Various factors such as heavy rainfall, industrial pumping, construction site excavation and drought can cause the static water level to drop or rise. The nature and cause of sudden changes in the static water level are difficult to determine.

[0007] Therefore, how to determine the exchange position of replenishment water after the static water level changes is the key. Summary of the invention

[0008] 1. Technical issues to be resolved

[0009] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for detecting the natural potential in a well for detecting the source of water in a seismic water level observation well, which solves the technical problem that it is difficult to determine the exchange position of replenishment water in the existing seismic fluid observation.

[0010] (II) Technical solution

[0011] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0012] The embodiment of the present invention provides a method for detecting the natural potential in a well of a well for observing the water source of a seismic water level. A monitoring system is used to implement the method for detecting the natural potential in a well of a well for observing the water source of a seismic water level. The monitoring system includes: a notebook terminal and a collector connected thereto; the collector is also connected to a zero potential electrode and a measuring cable respectively; the method includes:

[0013] S1. The collector in the monitoring system collects the potential value measured by the zero potential electrode, and sends the potential value measured by the zero potential electrode to the notebook terminal;

[0014] The zero potential electrode is pre-buried at a designated zero potential point on the ground surface;

[0015] S2. According to the wellbore depth of the observation well, adjust the spacing between the non-polarized electrodes in the measuring cable;

[0016] The measuring cable comprises four measuring wire cores, and the four measuring wire cores are respectively connected to four non-polarizable electrodes one by one;

[0017] S3, gradually lowering the measuring cable from the wellhead of the observation well until the non-polarized electrode at the bottom of the measuring cable is lowered to the bottom of the well. During the lowering of the measuring cable, the collector in the monitoring system collects the potential value measured by each non-polarized electrode in the measuring cable according to a preset collection interval, and sends the potential value measured by each non-polarized electrode in the measuring cable to the notebook terminal;

[0018] S4, the notebook terminal obtains the natural potential value of each non-polarizable electrode according to the potential value measured by each non-polarizable electrode in the measuring cable and the potential value measured by the zero potential electrode, and draws a curve of the natural potential values ​​of the four non-polarizable electrodes in real time;

[0019] S5. The notebook terminal determines the layer for exchanging water with the outside world based on the natural potential value curves of the four non-polarizable electrodes.

[0020] Preferably,

[0021] The distance between the zero potential position on the ground surface and the wellhead of the observation well is greater than or equal to 50 meters.

[0022] Preferably,

[0023] When the zero potential electrode is buried at the zero potential point position on the ground surface, salt water is poured in.

[0024] Preferably,

[0025] The distance between any two adjacent non-polarized electrodes in the measuring cable is 10 meters, and the four non-polarized electrodes are arranged vertically at equal intervals.

[0026] Preferably,

[0027] The difference between any two non-polarized electrodes in the measuring cable is less than 0.1mV.

[0028] The outer side of the measuring cable is provided with a water-impermeable protective layer.

[0029] Preferably,

[0030] The preset collection interval is 1 s.

[0031] Preferably,

[0032] During the process of lowering the measuring cable, when the non-polarized electrode at the bottom of the measuring cable is lowered to each type of formation, it stays for a preset measurement time. After the potential value measured by the non-polarized electrode reaches a preset value, the measuring cable is lowered again until the non-polarized electrode at the bottom of the measuring cable is lowered to the bottom of the well.

[0033] Preferably,

[0034] The preset time is 5 minutes;

[0035] The preset value is 300.

[0036] Preferably,

[0037] The natural potential value of the non-polarizable electrode is the difference between the potential value measured by the non-polarizable electrode and the potential value measured by the zero potential electrode.

[0038] Preferably, the S5 specifically includes:

[0039] The notebook terminal determines the layer for exchanging water with the outside world based on the natural potential value curves of the four non-polarizable electrodes;

[0040] The layer that exchanges water with the outside world is a layer where the natural potential value curves of the four non-polarized electrodes show a positive and negative potential transition in the same type of formation or a formation that swings beyond a preset amplitude.

[0041] (III) Beneficial effects

[0042] The beneficial effects of the present invention are as follows: the method for detecting the natural potential in a well of a seismic water level observation well of the present invention adjusts the spacing between the non-polarized electrodes in the measuring cable according to the wellbore depth of the observation well; the measuring cable is gradually lowered from the wellhead of the observation well until the non-polarized electrode at the bottom of the measuring cable is lowered to the bottom of the well. During the lowering of the measuring cable, the monitoring system

[0043] The collector in the system collects the potential value measured by each non-polarized electrode in the measuring cable according to the preset collection interval, and sends the potential value measured by each non-polarized electrode in the measuring cable to the

[0044] to a notebook terminal; the notebook terminal obtains the natural potential value of each non-polarized electrode according to the potential value measured by each non-polarized electrode in the measuring cable and the potential value measured by the zero potential electrode, and draws a curve of the natural potential values ​​of the four non-polarized electrodes in real time; the notebook terminal

[0045] The terminal determines the inflow point of external water based on the natural potential value curve of the four non-polarized electrodes. Compared with the existing technology, the different exchange rates of ions in different layers in the wellbore are used.

[0046] The purpose of detecting the change of natural potential with depth in the well and determining the layer exchanging with external water based on the natural potential value curve of the four non-polarizable electrodes is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A natural potential method in a well for detecting the source of water in a seismic water level observation well according to the present invention;

[0048] Figure 2 A schematic diagram of the structure of a monitoring system for realizing a method of detecting the natural potential in a well of water source for seismic water level observation wells according to the present invention;

[0049] Figure 3 This is a schematic diagram of the arrangement of the four internal measurement wire cores in the measurement cable;

[0050] Figure 4 This is a schematic diagram of the monitoring system in operation;

[0051] Figure 5 It is a schematic diagram of the natural potential value curve of four non-polarizable electrodes;

[0052] Figure 6 This is a connection diagram of the monitoring system.

[0053] [Description of Reference Numerals]

[0054] 101. Impermeable protective layer;

[0055] 102. Non-polarizable electrode;

[0056] 5103, electrode traction wire;

[0057] 104. Measuring wire core;

[0058] 201. Aquiferous strata;

[0059] 202. Impermeable strata;

[0060] 203. Measurement cable;

[0061] 204. Collector;

[0062] 205. Notebook terminal;

[0063] 206. Zero potential electrode;

[0064] 207. Natural potential curve;

[0065] 208. Observation of the well wall;

[0066] 301, the natural potential value curve corresponding to the non-polarized electrode 102 at the shallowest position;

[0067] 302. A natural potential value curve corresponding to the non-polarized electrode 102 at a second shallow position;

[0068] 303. A natural potential value curve corresponding to the non-polarized electrode 102 at the third shallow position;

[0069] 304. The natural potential value curve corresponding to the non-polarizable electrode 102 at the deepest position;

[0070] 401, power cord;

[0071] 402, electrode measurement line;

[0072] 403, zero potential measurement line;

[0073] 404, type_C terminal line. DETAILED DESCRIPTION

[0074] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0075] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0076] See also Figure 1 This embodiment provides a method for detecting the natural potential in a well of the source of water for earthquake water level observation. A monitoring system is used to implement the method for monitoring the natural potential in a well of the source of water for earthquake water level observation. Figure 2 , the monitoring system includes: a notebook terminal and a collector connected thereto; the collector is also connected to a zero potential electrode and a measuring cable respectively; the method includes:

[0077] S1. The collector in the monitoring system collects the potential value measured by the zero potential electrode, and sends the potential value measured by the zero potential electrode to a notebook terminal.

[0078] The zero potential electrode is pre-buried at a designated zero potential point on the ground surface.

[0079] In this embodiment, the distance between the zero potential position on the ground surface and the wellhead of the observation well is greater than or equal to 50 meters. When the zero potential electrode is buried at the zero potential point position on the ground surface, salt water is poured.

[0080] Specifically, by setting a zero potential position on the ground surface, which should generally be more than 50m away from the mouth of the observation well, a zero potential electrode is buried in a humid environment. During the burial process, a pit needs to be dug and poured with semi-saturated salt water to increase the good contact performance of the electrode.

[0081] S2. According to the wellbore depth of the observation well, adjust the spacing between the non-polarized electrodes in the measuring cable;

[0082] See also Figure 3 The measuring cable includes four measuring wire cores 104 , and the four measuring wire cores 104 are connected to four non-polarized electrodes 102 one by one respectively; the measuring wire cores 104 in this embodiment are connected to the non-polarized electrodes 102 through electrode pulling wires 103 .

[0083] See also Figure 3 In the practical application of this embodiment, the distance between any two adjacent non-polarized electrodes in the measuring cable is 10 meters, and the four non-polarized electrodes are arranged vertically at equal intervals. The range difference between any two non-polarized electrodes in the measuring cable is less than 0.1 mV. A watertight protective layer 101 is provided on the outer side of the measuring cable.

[0084] S3. The measuring cable is gradually lowered from the wellhead of the observation well until the non-polarized electrode at the bottom of the measuring cable is lowered to the bottom of the well. During the lowering process of the measuring cable, the collector in the monitoring system collects the potential value measured by each non-polarized electrode in the measuring cable according to the pre-set collection interval, and sends the potential value measured by each non-polarized electrode in the measuring cable to the notebook terminal.

[0085] The preset collection interval is 1 s.

[0086] Specifically, during the process of lowering the measuring cable, when the non-polarized electrode at the bottom of the measuring cable is lowered to each type of formation, it stays for a preset measurement time. After the potential value measured by the non-polarized electrode reaches a preset value, the measuring cable is lowered again until the non-polarized electrode at the bottom of the measuring cable is lowered to the bottom of the well.

[0087] See also Figure 4 The wellbore formation is complex, and there are at least two types of formations in the wellbore, such as a water-bearing formation 201 and an impermeable formation 202. There is basically no water exchange between the aquifer and the inside of the wellbore, and external water may enter the wellbore from the water-bearing formation 201 and then undergo ion exchange.

[0088] See also Figure 4The measuring cable 203 is placed in the wellbore and connected to the collector 204 outside the wellhead. The collector 204 is connected to the laptop terminal 205. Meanwhile, the collector 204 outside the wellhead is also connected to the zero potential electrode 206. The laptop terminal 205 displays the measured natural potential value in real time. The laptop terminal 205 also displays the natural potential curve 207. Figure 4 The wellbore of the middle observation well is 208.

[0089] The preset time is 5 minutes.

[0090] The preset value is 300.

[0091] S4. The notebook terminal obtains the natural potential value of each non-polarizable electrode according to the potential value measured by each non-polarizable electrode in the measuring cable and the potential value measured by the zero potential electrode, and draws a curve of the natural potential values ​​of the four non-polarizable electrodes in real time.

[0092] S5. The notebook terminal determines the layer for exchanging water with the outside world based on the natural potential value curves of the four non-polarizable electrodes.

[0093] The natural potential value of the non-polarizable electrode is the difference between the potential value measured by the non-polarizable electrode and the potential value measured by the zero potential electrode. The natural potential measures the difference between the ion potential inside the wellbore and the outside. The reference zero potential electrode is placed tens of meters outside the wellhead, the electrode is buried more than 30 cm deep and poured with semi-saturated brine.

[0094] See also Figure 5 Compared with other hydrogeochemical methods and hydrological gradient methods, the measurement of natural potential can directly reflect the ion distribution state of water at the depth of the wellbore formation. By comparing the gradient distribution of natural potential at different depths, the source and scale of water recharge in the wellbore can be analyzed in combination with the water temperature gradient and the wellbore hydrogeological conditions.

[0095] like Figure 5 As shown in the figure, the natural potential shows a trend of positive and negative potential transition in the permeable layer in the wellbore.

[0096] However, other observations such as water temperature gradient observations did not show a direct response, indicating that natural potential measurements are more sensitive and direct to water-rock reactions and heavy metal ion exchange in external sewage.

[0097] The natural potential measurement array gradually descends to the bottom of the well, and the data is transmitted to a laptop computer to draw a curve of the natural potential measurement in real time. The natural potential value curves of the four non-polarized electrodes are compared. When the four curves show a positive and negative potential transition or a large swing at the same layer, it indicates that the water-rock reaction is strong at that location. The infiltration layer of water from outside the wellbore can be determined based on this, which serves as the basic criterion for determining the source of the water flow.

[0098] 0See Figure 5 The natural potential value curves of the four non-polarized electrodes are respectively

[0099] The natural potential value curve 301 corresponding to the electrode 102, the natural potential value curve 302 corresponding to the non-polarized electrode 102 at the second shallow position, the natural potential value curve 303 corresponding to the non-polarized electrode 102 at the third shallow position, and the natural potential value curve 304 corresponding to the non-polarized electrode 102 at the deepest position.

[0100] The S5 specifically includes: the notebook terminal determines the layer for exchanging with external water based on the natural potential value curve of the four non-polarizable electrodes;

[0101] The layer that exchanges water with the outside world is a layer where the natural potential value curves of the four non-polarized electrodes show a positive and negative potential transition in the same type of formation or a formation that swings beyond a preset amplitude.

[0102] Near the wellbore, the water temperature at the wellhead is higher than that below due to the heating of the ground temperature, and the measured value of the 0 natural potential may also be unstable. In addition, the metal ion content is also affected by the casing.

[0103] Higher than the deep part without casing.

[0104] The measurement of natural potential by gradient electrode method can, on the one hand, repeat the test result of the previous electrode, and on the other hand, realize the observation of vertical geoelectric field, that is, taking the tail electrode as the zero potential electrode can obtain the measured value of vertical geoelectric field.

[0105] 5. Figure 6 As shown, the terminals of the observation system are collectors and ordinary notebook terminals, which are easy to carry and highly stable. The line connection is also simple and easy to operate, and does not require a lot of preparation before observation. This is very important for the requirement to quickly test and give judgment opinions after abnormalities occur in static water level observations.

[0106] In this embodiment, the collector is connected to the power supply through the power line 401, the collector is connected to the zero potential electrode through the zero potential measurement line 403, the collector is connected to the measurement cable through the electrode measurement line 402, and the collector is connected to the notebook terminal through the type_C terminal line 404.

[0107] The natural potential measurements during observation can be read in real time, and the curves of the measurements can be drawn in real time, which is very timely for judging abnormal conditions in the wellbore. Preliminary opinions can be given in real time based on the surrounding hydrogeological environment and rainfall response, which is critical for judging whether water level and water temperature anomalies are related to earthquake incubation.

[0108] The natural potential detection method directly detects the ion potential in the water body, reflecting the differences in ion content in various strata of the seismic water level observation well. It can more sensitively detect the source of active water supply around the wellbore. When these supply sources are excluded and do not cause abnormalities in the observation parameters of the seismic fluid well, it can be transformed into considering the adjustment of regional stress and strain over a wide range.

[0109] Seismic fluid observation is extremely important for earthquake precursor judgment and is the basis for timely and effective judgment of earthquake danger. The gradient natural potential measurement in the present invention can provide more accurate data for abnormal verification of seismic fluid observation to ensure the accuracy of judgment of earthquake danger and urgency of earthquake occurrence.

[0110] The invention discloses a method for detecting the natural potential in a well for detecting the water source of a seismic water level observation well. The method comprises the following steps: adjusting the spacing between non-polarized electrodes in a measuring cable according to the wellbore depth of the observation well; gradually lowering the measuring cable from the wellhead of the observation well until the non-polarized electrode at the bottom of the measuring cable is lowered to the bottom of the well. During the lowering of the measuring cable, a collector in a monitoring system collects the potential value measured by each non-polarized electrode in the measuring cable according to a preset collection interval, and sends the potential value measured by each non-polarized electrode in the measuring cable to a notebook terminal. The notebook terminal obtains the natural potential value of each non-polarized electrode according to the potential value measured by each non-polarized electrode in the measuring cable and the potential value measured by the zero potential electrode, and draws a curve of the natural potential values ​​of four non-polarized electrodes in real time. The notebook terminal determines the inflow location of external water based on the natural potential value curves of the four non-polarized electrodes. Compared with the existing technology, the different exchange degrees of ion contents in different layers in the wellbore are utilized to achieve the purpose of monitoring the change of natural potential in the well with depth and determining the layer that exchanges water with the outside world based on the natural potential value curve of the four non-polarized electrodes.

[0111] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0112] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions.

[0113] It should be noted that in the claims, any reference numerals placed between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In the claims enumerating several means, several of these means may be embodied by the same hardware. The use of the words first, second, third, etc., is for convenience of expression only and does not indicate any order. These words may be understood as part of the component name.

[0114] In addition, it should be noted that, in the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0115] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments after knowing the basic creative concept. Therefore, the claims should be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0116] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention should also include these modifications and variations.

Claims

1. A method for detecting the natural potential in a well for detecting the source of water in a seismic water level observation well, characterized in that: The method for detecting the natural potential in the well of the seismic water level observation well is implemented by using a monitoring system, the monitoring system includes: a notebook terminal and a collector connected thereto; the collector is also connected to a zero potential electrode and a measuring cable respectively; the method includes: S1. The collector in the monitoring system collects the potential value measured by the zero potential electrode, and sends the potential value measured by the zero potential electrode to the notebook terminal; The zero potential electrode is pre-buried at a designated zero potential point on the ground surface; S2. According to the wellbore depth of the observation well, adjust the spacing between the non-polarized electrodes in the measuring cable; The measuring cable comprises four measuring wire cores, and the four measuring wire cores are respectively connected to four non-polarizable electrodes one by one; S3, gradually lowering the measuring cable from the wellhead of the observation well until the non-polarized electrode at the bottom of the measuring cable is lowered to the bottom of the well. During the lowering of the measuring cable, the collector in the monitoring system collects the potential value measured by each non-polarized electrode in the measuring cable according to a preset collection interval, and sends the potential value measured by each non-polarized electrode in the measuring cable to the notebook terminal; S4, the notebook terminal obtains the natural potential value of each non-polarizable electrode according to the potential value measured by each non-polarizable electrode in the measuring cable and the potential value measured by the zero potential electrode, and draws a curve of the natural potential values ​​of the four non-polarizable electrodes in real time; S5. The notebook terminal determines the layer for exchanging water with the outside world based on the natural potential value curves of the four non-polarizable electrodes.

2. The natural potential method in a well according to claim 1, characterized in that: The distance between the zero potential position on the ground surface and the wellhead of the observation well is greater than or equal to 50 meters.

3. The natural potential method in a well according to claim 2, characterized in that: When the zero potential electrode is buried at the zero potential point position on the ground surface, salt water is poured in.

4. The natural potential method in a well according to claim 3, characterized in that: The distance between any two adjacent non-polarized electrodes in the measuring cable is 10 meters, and the four non-polarized electrodes are arranged vertically at equal intervals.

5. The natural potential method in a well according to claim 4, characterized in that: The range between any two non-polarized electrodes in the measuring cable is less than 0.1mV; The outer side of the measuring cable is provided with a water-impermeable protective layer.

6. The natural potential method in a well according to claim 5, characterized in that: The preset collection interval is 1 s.

7. The natural potential method in a well according to claim 6, characterized in that: During the process of lowering the measuring cable, when the non-polarized electrode at the bottom of the measuring cable is lowered to each type of formation, it stays for a preset measurement time. After the potential value measured by the non-polarized electrode reaches a preset value, the measuring cable is lowered again until the non-polarized electrode at the bottom of the measuring cable is lowered to the bottom of the well.

8. The natural potential method in a well according to claim 7, characterized in that: The preset time is 5 minutes; The preset value is 300.

9. The natural potential method in a well according to claim 8, characterized in that: The natural potential value of the non-polarizable electrode is the difference between the potential value measured by the non-polarizable electrode and the potential value measured by the zero potential electrode.

10. The natural potential method in a well according to claim 9, characterized in that: The S5 specifically includes: The notebook terminal determines the inflow location of the external water based on the natural potential value curve of the four non-polarizable electrodes; The inflow location of the external water is a formation where the natural potential value curves of the four non-polarized electrodes show a positive-negative potential transition in the same type of formation or a formation where the swing exceeds a preset amplitude.

Images