Method for determining spatial distribution of seepage dominant channel of halogen storage layer in dry salt lake

Abstract

The application discloses a method for determining the spatial distribution of seepage dominant channels of a dry salt lake halogen storage layer, which comprises the following steps: selecting at least one hydrological observation line between a water supplement channel and a halogen extraction channel, interval arranging a plurality of first-level observation holes penetrating aquifers on the hydrological observation line, collecting halogen water samples in the plurality of first-level observation holes and performing detection to obtain second-level control observation holes, taking the second-level control observation holes as centers, and interval arranging at least three second-level observation holes; collecting halogen water samples in the plurality of second-level observation holes and performing detection to screen out second-level observation holes located on seepage dominant channels, and the screening is continued until a plurality of observation holes located on seepage dominant channels are obtained, and the region where the plurality of observation holes are located is the spatial distribution of the seepage dominant channels. The application can quickly determine the spatial distribution of seepage dominant channels of a dry salt lake halogen storage layer only by means of drilling and halogen water chemical characteristic detection.

Description

Technical Field

[0001] This invention specifically relates to a method for determining the spatial distribution of dominant seepage channels in a dry salt lake brine reservoir, belonging to the field of salt lake development technology. Background Technology

[0002] Modern salt lake brine reservoirs are composed of water-soluble halite and silt, and contain small amounts of other evaporite minerals such as gypsum, mirabilite, carnallite, potassium halite, and other halide.

[0003] Low-grade solid potassium salt deposits such as carnallite and other carnallite in brine reservoirs serve as supplementary potassium salt resources besides brine resources. Extracting these resources using water-soluble methods is technically feasible and cost-effective. Currently, salt lake enterprises in the Qaidam Basin all employ this method to extract low-grade solid potassium salt resources. However, during water-soluble extraction, dominant dissolution channels are commonly found in the brine reservoir due to the seepage and dissolution of low-concentration solutions. These dominant channels significantly reduce the efficiency of potassium salt solid-liquid conversion. Furthermore, due to the high conductivity of the brine reservoir and the contained brine, many geophysical exploration methods struggle to determine the spatial distribution of these dominant channels. Identifying the distribution of these dominant channels and taking timely measures to avoid economic losses from ineffective water replenishment caused by them is a crucial task in the current development of salt lake resources. Summary of the Invention

[0004] The main objective of this invention is to provide a method for determining the spatial distribution of dominant seepage channels in dry salt lake brine reservoirs, thereby overcoming the shortcomings of existing technologies.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0006] This invention provides a method for determining the spatial distribution of dominant seepage channels in a dry brine reservoir, comprising:

[0007] S1) A hydrological observation line is laid between the water replenishment channel and the brine extraction channel. The hydrological observation line is set parallel to the water replenishment channel and / or the brine extraction channel, and has a first distance d1 between it and the water replenishment channel.

[0008] S2) Multiple first-level observation holes that penetrate the desiccation layer are arranged at intervals along the hydrological observation line, with a second spacing d2 between two adjacent first-level observation holes;

[0009] S3) Collect brine samples from multiple first-level observation wells and perform tests to obtain the chemical characteristics of multiple brine samples. Mark the first-level observation wells corresponding to brine samples with selected chemical characteristics, wherein the chemical characteristics include mineralization, conductivity and constant ion content.

[0010] S4) Select at least one of the marked first-level observation holes as a second-level control observation hole, and arrange at least three second-level observation holes at intervals with the second-level control observation hole as the center. There is a third distance d3 between the second-level observation hole and the second-level control observation hole, and the third distance d3 is smaller than the second distance d2.

[0011] Among them, at least two second-level observation holes are arranged at intervals on both sides of the second-level control observation hole in a direction parallel to the water replenishment channel, and at least one second-level observation hole is arranged at intervals on the side of the second-level control observation hole facing the brine extraction channel in a direction perpendicular to the water replenishment channel.

[0012] S5) Collect brine samples from multiple secondary observation wells and perform tests to obtain the chemical characteristics of multiple brine samples, and mark the secondary observation wells corresponding to the brine samples with selected chemical characteristics.

[0013] S6) Repeat S4) and S5) at least once.

[0014] S7) Select at least one of the marked (n-1) level observation wells as the nth level control observation well, and arrange at least three nth level observation wells at intervals with the nth level control observation well as the center.

[0015] Among them, at least two nth-level observation holes are arranged at intervals on both sides of the nth-level control observation hole along a direction parallel to the water replenishment channel, and at least one nth-level observation hole is arranged at intervals on the side of the nth-level control observation hole facing the brine extraction channel along a direction perpendicular to the water replenishment channel. The nth-level observation holes are located between the water replenishment channel and the brine extraction channel. The distance between the nth-level observation hole and the nth-level control observation hole is the third distance d3. The vertical distance between the nth-level observation hole and the brine extraction channel is less than the third distance d3, and n≥3.

[0016] S8) Collect brine samples from multiple nth-level observation wells and perform tests to obtain the chemical characteristics of multiple brine samples, and mark the nth-level observation wells corresponding to the brine samples with selected chemical characteristics.

[0017] The area where all the marked observation wells are located represents the spatial distribution of the dominant seepage channels.

[0018] Compared with existing technologies, the method for determining the spatial distribution of dominant seepage channels in dry brine reservoirs provided by this invention is simple to operate. It can quickly determine the spatial distribution of dominant seepage channels in dry brine reservoirs by means of drilling and brine chemical characteristic detection, thereby improving the efficiency of determining the spatial distribution of dominant seepage channels in dry brine reservoirs and reducing the cost of confirming the spatial distribution of dominant seepage channels in dry brine reservoirs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating the principle of a method for determining the spatial distribution of dominant seepage channels in a dry salt lake brine reservoir, provided in a typical embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of a salt lake brine reservoir and observation holes provided in a typical embodiment of the present invention. Detailed Implementation

[0021] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0022] This invention provides a method for determining the spatial distribution of dominant seepage channels in a dry brine reservoir, comprising:

[0023] S1) A hydrological observation line is laid between the water replenishment channel and the brine extraction channel. The hydrological observation line is set parallel to the water replenishment channel and / or the brine extraction channel, and has a first distance d1 between it and the water replenishment channel.

[0024] S2) Multiple first-level observation holes that penetrate the desiccation layer are arranged at intervals along the hydrological observation line, with a second spacing d2 between two adjacent first-level observation holes;

[0025] S3) Collect brine samples from multiple first-level observation wells and perform tests to obtain the chemical characteristics of multiple brine samples. Mark the first-level observation wells corresponding to brine samples with selected chemical characteristics, wherein the chemical characteristics include mineralization, conductivity and constant ion content.

[0026] S4) Select at least one of the marked first-level observation holes as a second-level control observation hole, and arrange at least three second-level observation holes at intervals with the second-level control observation hole as the center. There is a third distance d3 between the second-level observation hole and the second-level control observation hole, and the third distance d3 is smaller than the second distance d2.

[0027] Among them, at least two second-level observation holes are arranged at intervals on both sides of the second-level control observation hole in a direction parallel to the water replenishment channel, and at least one second-level observation hole is arranged at intervals on the side of the second-level control observation hole facing the brine extraction channel in a direction perpendicular to the water replenishment channel.

[0028] S5) Collect brine samples from multiple secondary observation wells and perform tests to obtain the chemical characteristics of multiple brine samples, and mark the secondary observation wells corresponding to the brine samples with selected chemical characteristics.

[0029] S6) Repeat S4) and S5) at least once;

[0030] S7) Select at least one of the marked (n-1) level observation wells as the nth level control observation well, and arrange at least three nth level observation wells at intervals with the nth level control observation well as the center.

[0031] Among them, at least two nth-level observation holes are arranged at intervals on both sides of the nth-level control observation hole along a direction parallel to the water replenishment channel, and at least one nth-level observation hole is arranged at intervals on the side of the nth-level control observation hole facing the brine extraction channel along a direction perpendicular to the water replenishment channel. The nth-level observation holes are located between the water replenishment channel and the brine extraction channel. The distance between the nth-level observation hole and the nth-level control observation hole is the third distance d3. The vertical distance between the nth-level observation hole and the brine extraction channel is less than the third distance d3, and n≥3.

[0032] S8) Collect brine samples from multiple nth-level observation wells and perform tests to obtain the chemical characteristics of multiple brine samples. Mark the nth-level observation wells corresponding to the brine samples with selected chemical characteristics. The area where all the marked observation wells are located is the spatial distribution of the dominant seepage channels.

[0033] It should be noted that the observation wells corresponding to brine samples with selected chemical characteristics are located in the region where the seepage is dominant, and the dewatering layer refers to the layer above the aquifer water level.

[0034] In one specific embodiment, the method for determining the spatial distribution of dominant seepage channels in the dry salt lake brine reservoir includes: setting up first-level observation wells according to the requirements for the layout of groundwater monitoring points in the mining area under the condition that the mining area is located in the same hydrogeological unit, as specified in the Technical Specification for Groundwater Environmental Monitoring (HJ164-2020).

[0035] In one specific embodiment, the method for determining the spatial distribution of dominant seepage channels in the dry salt lake reservoir includes: setting up a first-level observation hole from the first end of the hydrological observation line, and setting up a first-level observation hole every second interval, until the last first-level observation hole is located at the second end of the hydrological observation line, or the distance between the last first-level observation hole and the second end of the hydrological observation line is less than the third interval.

[0036] In one specific embodiment, the second spacing d2 is 5-20 times the first spacing d1.

[0037] In one specific embodiment, the ratio of the length of the third spacing d3 to the length of the second spacing d2 is (3-5)∶(50-100).

[0038] In one specific embodiment, the second spacing d2 is 500m-1000m, and the third spacing d3 is 30m-50m.

[0039] In one specific embodiment, the vertical distance d1 between the hydrological observation line and the water replenishment channel is greater than 0 and less than or equal to 1 / 5 of the vertical distance d4 between the water replenishment channel and the brine extraction channel.

[0040] In one specific embodiment, the vertical distance d1 between the hydrological observation line and the water replenishment channel is 1 / 20 to 1 / 5 of the vertical distance d4 between the water replenishment channel and the brine extraction channel.

[0041] In one specific embodiment, the vertical distance d4 between the water replenishment channel and the brine extraction channel is 500-1000m.

[0042] In one specific embodiment, the vertical distance d1 between the hydrological observation line and the water replenishment channel is 50-100m.

[0043] In one specific embodiment, the hydrological observation line is equal in length to the water replenishment canal.

[0044] In one specific embodiment, the first-level control observation well is the brine sample with the lowest values ​​of mineralization, conductivity, and constant ion content among the multiple first-level observation wells.

[0045] In one specific embodiment, the constant ions include sodium ions and / or chloride ions.

[0046] In one specific embodiment, a brine sample with selected chemical characteristics refers to a mineralization degree of less than 315 g / L, a specific gravity of less than 1.21, an electrical conductivity of 130-170 mS / cm, and a Na+ content of [missing information]. + The content is 50-70g / L, Cl - Brine samples with a content of less than 200 g / L.

[0047] In one specific embodiment, the aperture of the first-level observation hole, the second-level observation hole, ..., the nth-level observation hole is 3.5-5.5 cm.

[0048] In one specific embodiment, the first-level observation well, the second-level observation well, ..., the nth-level observation well extend downward to the surface of the aquifer.

[0049] In one specific embodiment, the method for determining the spatial distribution of dominant seepage channels in the dry salt lake brine reservoir further includes: taking multiple control observation holes distributed on the outer boundary of the n control observation holes as the center, extending outward by a selected distance d5 in a direction parallel to the water replenishment channel, and the obtained new boundary is the boundary of the spatial distribution of the dominant seepage channels.

[0050] In one specific embodiment, the ratio of the length of the selected distance d5 to the length of the third distance d3 is (6-10)∶(30-50).

[0051] In one specific embodiment, the selected distance d5 is 6-10m.

[0052] The following will further explain the technical solution, its implementation process and principle in conjunction with the accompanying drawings and specific implementation examples. Unless otherwise specified, the excavation of the observation hole and other specific implementation steps in the embodiments of the present invention are carried out in accordance with the "Technical Specification for Groundwater Environmental Monitoring".

[0053] Example 1

[0054] Please see Figure 1 and Figure 2 In a typical implementation scheme, a method for determining the spatial distribution of dominant seepage channels in a dry brine reservoir may include the following steps:

[0055] 1) Based on the geological and hydrogeological characteristics of the salt lake, the borehole structure downstream of the water replenishment canal in the mining area was investigated to determine the lithology of the brine reservoir, the thickness of the brine reservoir, and the brine water level, and the vertical distance between the water replenishment canal and the brine extraction canal was found to be 1000m.

[0056] 2) A hydrological observation line shall be laid out parallel to the water replenishment channel and the brine extraction channel at a location 100m away from the water replenishment channel. The length of the hydrological observation line shall be the same as the length of the water replenishment channel. Starting from one end of the hydrological observation line, in accordance with the requirements for the layout of groundwater monitoring points in the mining area under the condition of the same hydrogeological unit in the "Technical Specification for Groundwater Environment Monitoring" HJ164-2020, a first-level observation well shall be arranged every 500m. The first-level observation well shall only penetrate to the water level of the shallow aquifer.

[0057] 3) Collect surface brine samples from each of the first-stage observation wells and measure and analyze the chemical characteristics of each brine sample. The chemical characteristics include total salinity (TDS), conductivity, specific gravity, and Na+. + Cl - Content; compare the chemical characteristics of brine samples in each first-stage observation well, and mark at least one first-stage observation well A0 corresponding to the brine sample with selected chemical characteristics. The marked first-stage observation well A0 is located on the seepage-dominant channel. The brine sample with selected chemical characteristics is defined as having a mineralization of less than 315 g / L, a specific gravity of less than 1.21, an electrical conductivity of 130-170 mS / cm, and Na+ content. + The content is 50-70g / L, Cl - Brine samples with a content of less than 200 g / L;

[0058] 4) Use the marked first-level observation well A0 as the second-level control observation well. With the second-level control observation well as the center, set up two second-level observation wells A1 at intervals of 50m along the direction parallel to the water replenishment channel, and set up one second-level observation well A1 along the side of the second-level control observation well facing the brine extraction channel along the direction perpendicular to the water replenishment channel. The three second-level observation wells A1 only need to penetrate to the water level of the shallow aquifer.

[0059] 5) Collect brine samples from the three secondary observation wells A1 and test them to obtain the chemical characteristics of the three brine samples. Select a secondary observation well A1 that has the same or similar chemical characteristics as the brine sample in the secondary control observation well and mark it. The marked secondary observation well A1 is located on the seepage dominant channel.

[0060] 6) Using the marked second-level observation hole A1 as the next-level control observation hole, refer to and repeat steps 4) and 5) once or more, drill to form the next-level observation hole and analyze the chemical characteristics of the brine sample. Find new observation holes located on the dominant seepage channel and use them as the next-level control observation holes. In this way, the new observation holes located on the dominant channel gradually approach the brine extraction channel in a direction perpendicular to the hydrological observation line. The drilling ends when the vertical distance between the position of the last formed observation hole and the brine extraction channel is less than 50m.

[0061] 7) Screen all the marked observation wells, extend the boundary of the area where the selected observation wells are located outward (which can be understood as parallel to the direction of the hydrological observation line) by 6m, and use the new boundary as the spatial distribution boundary of the seepage dominance channel. Then the area covered by these selected observation wells is the precise location of the spatial distribution of the seepage dominance channel.

[0062] In this embodiment, the depth of the observation hole formed by drilling is approximately 1m.

[0063] In this embodiment, the chemical characteristics of the brine sample in the hydrological observation well can be detected by a portable multi-parameter water quality analyzer.

[0064] The present invention provides a method for determining the spatial distribution of dominant seepage channels in a dry brine reservoir. The method is simple to operate and can quickly determine the spatial distribution of dominant seepage channels in a dry brine reservoir by means of drilling and brine chemical characteristic detection, thereby improving the efficiency of determining the spatial distribution of dominant seepage channels in a dry brine reservoir and reducing the cost of confirming the spatial distribution of dominant seepage channels in a dry brine reservoir.

[0065] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for determining the spatial distribution of seepage preferential channels in a halogen storage layer of a dry salt lake, characterized in that, Comprising: S1) arranging a hydrological observation line between the replenishment channel and the brine extraction channel, the hydrological observation line being arranged parallel to the replenishment channel and / or the brine extraction channel, and having a first spacing d1 with the replenishment channel; S2) arranging a plurality of first-level observation holes penetrating the desiccation layer at intervals on the hydrological observation line, adjacent two first-level observation holes having a second spacing d2 therebetween; S3) collecting brine samples in the plurality of first-level observation holes and detecting the same to obtain chemical characteristics of the plurality of brine samples, and marking the first-level observation holes corresponding to the brine samples having selected chemical characteristics, wherein the chemical characteristics include salinity, conductivity and constant ion content; S4) selecting at least one of the marked first-level observation holes as a second-level control observation hole, and arranging at least three second-level observation holes at intervals with the second-level control observation hole as the center, the second-level observation holes having a third spacing d3 with the second-level control observation hole, and the third spacing d3 being smaller than the second spacing d2; wherein at least two second-level observation holes are arranged at intervals on both sides of the second-level control observation hole in a direction parallel to the replenishment channel, and at least one second-level observation hole is arranged at intervals on one side of the second-level control observation hole facing the brine extraction channel in a direction perpendicular to the replenishment channel; S5) collecting brine samples in the plurality of second-level observation holes and detecting the same to obtain chemical characteristics of the plurality of brine samples, and marking the second-level observation holes corresponding to the brine samples having selected chemical characteristics; S6) repeating S4) and S5) for more than once, S7) selecting at least one of the marked (n-1)th-level observation holes as an nth-level control observation hole, and arranging at least three nth-level observation holes with the nth-level control observation hole as the center; wherein at least two nth-level observation holes are arranged at intervals on both sides of the nth-level control observation hole in a direction parallel to the replenishment channel, and at least one nth-level observation hole is arranged at intervals on one side of the nth-level control observation hole facing the brine extraction channel in a direction perpendicular to the replenishment channel, and the nth-level observation hole is located between the replenishment channel and the brine extraction channel, the spacing between the nth-level observation hole and the nth-level control observation hole being the third spacing d3, and the vertical distance between the nth-level observation hole and the brine extraction channel being smaller than the third spacing d3, n≥3; S8) collecting brine samples in the plurality of nth-level observation holes and detecting the same to obtain chemical characteristics of the plurality of brine samples, and marking the nth-level observation holes corresponding to the brine samples having selected chemical characteristics; The region where all the marked observation holes are located is the spatial distribution of the percolation dominant channel.

2. The method of claim 1, wherein, Comprising: arranging a first first-level observation hole from the first end of the hydrological observation line, and arranging a first-level observation hole at intervals of the second spacing until the last first-level observation hole is located at the second end of the hydrological observation line, or the distance between the last first-level observation hole and the second end of the hydrological observation line is smaller than the third spacing.

3. The method of claim 1 or 2, wherein the method further comprises: determining the spatial distribution of the flow channels in the salt lake. The second spacing d2 is 5-20 times the first spacing d1.

4. The method of claim 1 or 2, wherein the method further comprises: determining the spatial distribution of the flow channels in the salt lake. The ratio of the length of the third spacing d3 to the second spacing d2 is (3-5):(50-100).

5. The method of determining the spatial distribution of the seepage channel of the halogen storage layer of the salt lake according to claim 1 or 2, characterized in that: The second distance d2 is 500-1000 m, and the third distance d3 is 30-50 m.

6. The method of claim 1, wherein the method further comprises: determining the spatial distribution of the preferential flow paths in the salt lake reservoir. The vertical distance d1 between the hydrological observation line and the water replenishing channel is greater than 0 and less than or equal to 1 / 5 of the vertical distance d4 between the water replenishing channel and the brine collecting channel.

7. The method of claim 1, wherein the method further comprises: determining the spatial distribution of the preferential flow paths in the salt lake reservoir. The vertical distance d1 between the hydrological observation line and the water replenishing channel is 1 / 20-1 / 5 of the vertical distance d4 between the water replenishing channel and the brine collecting channel.

8. The method of determining the spatial distribution of the seepage dominant channel of the halogen storage layer of a salt lake according to claim 6 or 7, characterized in that: The vertical distance d4 between the water replenishing channel and the brine collecting channel is 500-1000 m.

9. The method of determining the spatial distribution of the seepage channel of the halogen storage layer of the salt lake according to claim 6 or 7, characterized in that: The vertical distance d1 between the hydrological observation line and the water replenishing channel is 50-100 m.

10. The method of claim 1, wherein the method further comprises: determining the spatial distribution of the preferential flow paths in the salt lake reservoir. The length of the hydrological observation line is equal to that of the water replenishing channel.

11. The method of claim 2, wherein the method further comprises: determining the spatial distribution of the preferential flow paths in the salt lake reservoir. The first-stage control observation hole is one with the smallest value of the salinity, the conductivity and the content of the constant ions of the brine sample among the multiple first-stage observation holes.

12. The method of determining the spatial distribution of the seepage channel of the halogen storage layer of the salt lake according to claim 1 or 11, characterized in that: Brine samples with selected chemical characteristics mean brines with a salinity of less than 315 g / L, a specific gravity of less than 1.21, an electrical conductivity of 130-170 mS / cm, a Na + content of 50-70 g / L, a Cl - content of less than 200 g / L.

13. The method of claim 1, wherein the method further comprises: determining the spatial distribution of the flow channels in the salt lake reservoir. The diameters of the first-stage observation hole, the second-stage observation hole, …, and the nth-stage observation hole are 3.5-5.5 cm.

14. The method of claim 1, wherein: The first-stage observation hole, the second-stage observation hole, …, and the nth-stage observation hole extend downward to the surface layer of the aquifer.

15. The method of claim 1, wherein, Further comprising: A new boundary is obtained by extending a selected distance d5 outward from each of the multiple control observation holes distributed on the peripheral boundary in a direction parallel to the water replenishing channel, and the new boundary is the boundary of the spatial distribution of the seepage dominant channel.

16. The method of claim 15, wherein the step of determining the spatial distribution of the preferential flow paths in the salt-lake reservoir is characterized by, The ratio of the length of the selected distance d5 to the length of the third distance d3 is (6-10):(30-50).

17. The method of claim 15, wherein the step of determining the spatial distribution of the preferential flow paths in the salt-lake reservoir is characterized by, The selected distance d5 is 6-10 m.

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