CN116291353A - Method for expanding in-situ leaching solvent sweep range of sandstone uranium ores - Google Patents

Method for expanding in-situ leaching solvent sweep range of sandstone uranium ores Download PDF

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CN116291353A
CN116291353A CN202310219004.8A CN202310219004A CN116291353A CN 116291353 A CN116291353 A CN 116291353A CN 202310219004 A CN202310219004 A CN 202310219004A CN 116291353 A CN116291353 A CN 116291353A
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uranium
ore
permeability
aquifer
bearing
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CN116291353B (en
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苏学斌
赵利信
陈梅芳
阙为民
陈希
程威
王亚奴
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Beijing Research Institute of Chemical Engineering and Metallurgy of CNNC
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Beijing Research Institute of Chemical Engineering and Metallurgy of CNNC
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    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/25Methods for stimulating production
    • E21B43/26Methods for stimulating production by forming crevices or fractures
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B29/00Cutting or destroying pipes, packers, plugs or wire lines, located in boreholes or wells, e.g. cutting of damaged pipes, of windows; Deforming of pipes in boreholes or wells; Reconditioning of well casings while in the ground
    • E21B29/08Cutting or deforming pipes to control fluid flow
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B33/00Sealing or packing boreholes or wells
    • E21B33/10Sealing or packing boreholes or wells in the borehole
    • E21B33/13Methods or devices for cementing, for plugging holes, crevices or the like
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/28Dissolving minerals other than hydrocarbons, e.g. by an alkaline or acid leaching agent
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/34Arrangements for separating materials produced by the well
    • E21B43/38Arrangements for separating materials produced by the well in the well
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00Survey of boreholes or wells
    • E21B47/10Locating fluid leaks, intrusions or movements
    • E21B47/11Locating fluid leaks, intrusions or movements using tracers; using radioactivity
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B49/00Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/20Recycling

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  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
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  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
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  • Manufacture And Refinement Of Metals (AREA)

Abstract

The invention discloses a method for expanding the in-situ leaching solution scope of sandstone uranium ores, which relates to the technical field of sandstone uranium ore in-situ leaching exploitation, wherein the distribution positions of strong permeability surrounding rocks and low permeability ore layers in a uranium-bearing ore water-bearing layer are determined according to a core logging result and a logging curve, then for each strong permeability surrounding rock, a sleeve and a cement ring in a cutting section of the strong permeability surrounding rock are cut, a built-in filter is placed in the cutting section, a temporary plugging agent is injected into the uranium-bearing ore water-bearing layer until the leaching solution only flows in the low permeability ore layer so as to reduce the permeability of the strong permeability surrounding rock, and finally blasting fracturing based on a horizontal well or a vertical well is carried out in the low permeability ore layer so as to improve the permeability of the low permeability ore layer, thereby reducing the overall permeability difference of the uranium-bearing ore water-bearing layer of the sandstone, improving the scope of the leaching solution, and fully leaching the uranium-bearing ore water-bearing layer, and improving the recovery ratio of the sandstone uranium ore.

Description

Method for expanding in-situ leaching solvent sweep range of sandstone uranium ores
Technical Field
The invention relates to the technical field of sandstone uranium ore in-situ leaching exploitation, in particular to a method for expanding the scope of in-situ leaching solvent of sandstone uranium ore.
Background
The sandstone-type uranium deposit resources in the Erdos basin are very rich, and account for 50% of the natural uranium reserves currently ascertained in China. The resources of the sandstone type uranium deposit in North Hudous of the jaw, which are found at present, are mostly provided in midJurass Luo Tongzhi groups, the uranium deposit is distributed in a plate-shaped manner in a uranium-bearing ore water-bearing layer, the plane distribution of ore bodies is stable, the inclination angle is small (1-3 degrees), and the ore body thickness of part of the uranium deposit exceeds 10m. The in-situ leaching uranium extraction is a comprehensive mining method which is characterized in that uranium in sandstone-type uranium ores is dissolved out from natural buried conditions by means of chemical reagents through drilling engineering, and the ore is not displaced, so that the method is a main mining mode of the sandstone-type uranium ores. In actual production, the flow range of the leaching agent is often limited due to the influence of the heterogeneous properties of the permeability of the rock formation, the mineral composition and the like during the transfer of the leaching agent from the injection well to the extraction well. For example, in a uranium-bearing aqueous layer in which a strong permeable zone exists, the leaching agent tends to rapidly migrate from the injection well to the withdrawal well without fully reacting with the ore, which wastes the leaching agent and does not leach uranium effectively, and the resource utilization is extremely low, resulting in an increase in production cost. In other low permeability sandstone uranium deposits (permeability coefficient <0.1 m/d), the ore is compact and hard, and the cementation degree is high, so that the leaching agent cannot effectively enter the ore bed to erode uranium-containing minerals, and sandstone uranium resources cannot be effectively recovered.
As mentioned above, the reasons for the limited reach of sandstone uranium ores during in-situ leaching are mainly due to the heterogeneity (i.e. strong permeability and low permeability) of the ore-bearing layer. Therefore, the method for researching how to improve the scope of the leaching agent of the uranium in the strong-permeability and low-permeability sandstone uranium deposit has great significance for improving the efficiency and the yield of the uranium in the on-site leaching and reducing the production cost, and is a problem to be solved in the field of the uranium in the on-site leaching at present.
Disclosure of Invention
The invention aims to provide a method for expanding the scope of leaching and leaching agents of sandstone uranium ores in situ, which adopts temporary plugging agents to reduce the permeability of strong permeability surrounding rock, adopts blasting fracturing to improve the permeability of low-permeability ore layers so as to reduce the overall permeability difference of the sandstone uranium ore uranium-bearing ore water layers and improve the scope of leaching agents, and can fully leach the uranium ore water layers, thereby improving the recovery ratio of the sandstone uranium ores.
In order to achieve the above object, the present invention provides the following solutions:
a method of expanding the reach of a leaching solution for sandstone uranium ores in situ, the method comprising:
collecting a core of a uranium-bearing ore aquifer of sandstone uranium ore, and analyzing the core to obtain a core catalogue result; performing geophysical prospecting well logging on the uranium-bearing ore aquifer to obtain a well logging curve; determining distribution positions of high-permeability surrounding rock and low-permeability ore layers in the uranium-bearing ore aquifer according to the core logging result and the logging curve;
cutting a sleeve and a cement sheath in a cutting section of the high-permeability surrounding rock for each high-permeability surrounding rock, and placing a built-in filter in the cutting section; injecting a temporary plugging agent into the uranium-bearing ore aquifer until the leaching agent flows only in the low permeability ore layer;
according to the thickness, shape and length of the uranium-bearing ore aquifer, horizontal well blasting or vertical well blasting is determined; if the horizontal well blasting is adopted, a horizontal well is directionally constructed in the low-permeability ore layer according to the ore body distribution of the low-permeability ore layer, and blasting fracturing of the low-permeability ore layer is carried out in the horizontal well; if the vertical well blasting is adopted, blasting fracturing of the low-permeability ore deposit is carried out in the vertical well.
In some embodiments, prior to the collecting the core of the uranium-bearing aquifer of sandstone uranium ores, the method further includes: and arranging drilling holes and drilling the drilling holes in the uranium-bearing ore aquifer of the sandstone uranium ore according to the on-site leaching uranium extraction requirement, so as to collect the core of the uranium-bearing ore aquifer in the drilling holes with the drilling holes completed and perform geophysical prospecting on the uranium-bearing ore aquifer.
In some embodiments, prior to said resecting casing and cement sheath in the cut section of the strong permeable surrounding rock, the method further comprises determining the cut section of the strong permeable surrounding rock, comprising:
judging whether the thickness of the surrounding rock with strong permeability is larger than or equal to a first set value;
if yes, the cutting length is smaller than or equal to the first set value;
if not, the cutting length is the thickness;
determining a cut segment of the highly permeable surrounding rock based on the cut length.
In some embodiments, the temporary plugging agent is Cr 3+ HPAM gel.
In some embodiments, the injecting the temporary plugging agent into the uranium containing ore aquifer until the leaching agent flows only in the low permeability ore layer specifically comprises:
injecting a tracer and a temporary plugging agent into the uranium-bearing ore aquifer, and simultaneously starting a liquid extraction system to obtain a first extracted liquid of the uranium-bearing ore aquifer;
analyzing the first extract, and drawing a first change curve of the concentration of the tracer in the first extract with time and a second change curve of the concentration of the temporary plugging agent in the first extract with time; determining a first time point when the peak value of the concentration of the tracer appears according to the first change curve, and determining a second time point when the peak value of the concentration of the temporary plugging agent appears according to the second change curve;
stopping the injection of the tracer after reaching the second time point, and continuing to inject the temporary plugging agent until the first time period is reached; stopping the injection of the temporary plugging agent and the liquid extraction system, and enabling the temporary plugging agent to precipitate and solidify in the uranium-bearing ore water-containing layer for a second time period;
injecting the tracer into the uranium-bearing ore aquifer, and simultaneously starting the liquid extraction system to obtain a second extracted liquid of the uranium-bearing ore aquifer;
analyzing the second extract, and drawing a third change curve of the concentration of the tracer in the second extract along with the change of time; determining a third point in time at which a peak in the concentration of the tracer occurs from the third profile; stopping the injection of the tracer and the extraction system after reaching the third point in time;
judging whether the time interval between the first time point and the third time point is larger than a second set value or not; if so, the leaching agent flows only in the low permeability seam; if not, returning to the step of continuously injecting the temporary plugging agent until the first time period is continued.
In some embodiments, the tracer is an alcohol or salt; the first period of time is 3 days; the second period of time is 7 days.
In some embodiments, the determining to use horizontal well blasting or to use vertical well blasting according to the thickness, morphology and length of the uranium-bearing ore aquifer specifically includes:
if the thickness of the uranium-bearing ore aquifer is larger than a third set value, the morphology is regular, and the length is larger than a fourth set value, horizontal well blasting is determined to be adopted;
and if the thickness of the uranium-containing ore aquifer is smaller than or equal to the third set value, the morphology is irregular, and the length is smaller than or equal to the fourth set value, determining to adopt vertical well blasting.
In some embodiments, the performing blasting fracturing of the low permeability seam in the horizontal well specifically comprises:
spacing fracturing devices in a horizontal section of the horizontal well to perform spaced blasting fracturing in the low permeability ore layer; the horizontal segment penetrates through the low-permeability ore layer along the trend of the ore body, and the projection of the horizontal segment on the horizontal plane is S-shaped.
In some embodiments, the performing the explosive fracturing of the low permeability seam in the vertical well specifically comprises:
determining a vertical section of a vertical well corresponding to the low permeability seam; and arranging fracturing devices at intervals in the vertical section so as to perform interval blasting fracturing in the low-permeability ore layer.
In some embodiments, after performing the explosive fracturing of the low permeability seam, the method further comprises:
injecting the tracer into the uranium-bearing ore aquifer, and simultaneously starting the liquid extraction system to obtain a third extracted liquid of the uranium-bearing ore aquifer;
analyzing the third extract, and drawing a fourth change curve of the concentration of the tracer in the third extract along with the change of time; determining a fourth point in time at which a peak in the concentration of the tracer occurs according to the fourth variation curve; stopping the injection of the tracer and the liquid extraction system after reaching the fourth time point;
determining whether a time interval between the third time point and the fourth time point corresponding to when the leaching agent flows only in the low permeability ore layer is less than a fifth set value; if not, injecting the temporary plugging agent into the uranium-containing ore aquifer, starting the liquid extraction system at the same time until the first time period is continued, stopping the injection of the temporary plugging agent and the liquid extraction system, enabling the temporary plugging agent to precipitate and solidify in the uranium-containing ore aquifer for the second time period, and returning the step of injecting the tracer into the uranium-containing ore aquifer, starting the liquid extraction system at the same time, and obtaining a third extracted liquid of the uranium-containing ore aquifer.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention provides a method for expanding the in-situ leaching solution sweep range of sandstone uranium ores, which comprises the steps of firstly collecting cores of uranium-bearing ore aquifers of the sandstone uranium ores, analyzing the cores, carrying out physical detection on the uranium-bearing ore aquifers, determining distribution positions of strong permeability surrounding rocks and low permeability ore aquifers in the uranium-bearing ore aquifers according to obtained core logging results and logging curves, then cutting sleeves and cement rings in cutting sections of the strong permeability surrounding rocks for each strong permeability surrounding rock, placing built-in filters in the cutting sections, injecting temporary plugging agents into the uranium-bearing ore aquifers until the leaching agents only flow in the low permeability ore aquifers to reduce the permeability of the strong permeability surrounding rocks, finally determining to adopt horizontal well blasting or vertical well blasting according to the thickness, form and length of the uranium-bearing ore aquifers, carrying out directional construction of the horizontal well in the low permeability ore aquifers according to the ore body distribution of the low permeability ore aquifers, carrying out vertical blasting of the low permeability surrounding rocks in the horizontal well, and carrying out vertical blasting of the low permeability ore aquifers in the low permeability ore aquifers, thereby reducing the overall permeability of the low permeability surrounding rock, and increasing the permeability of the low permeability ore aquifers, and improving the permeability of the low permeability surrounding rock, and the permeability of the low permeability ore aquifers by the low permeability blasting.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of the method according to embodiment 1 of the present invention;
FIG. 2 is a schematic diagram of a horizontal well blasting according to embodiment 1 of the present invention;
fig. 3 is a schematic view of a vertical well blast provided in example 1 of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a method for expanding the scope of leaching and leaching agents of sandstone uranium ores in situ, which adopts temporary plugging agents to reduce the permeability of strong permeability surrounding rock, adopts blasting fracturing to improve the permeability of low permeability ore layers, reduces the overall permeability difference of the sandstone uranium ore uranium-bearing ore water layers, improves the scope of leaching agents, can fully leach the uranium ore water layers, and improves the recovery ratio of the sandstone uranium ores.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
Example 1:
in view of the problem of in-situ leaching (in-situ leaching) of sandstone uranium ores, this embodiment is used to provide a method for expanding the scope of in-situ leaching solvent of sandstone uranium ores, as shown in fig. 1, where the method includes:
s1: collecting a core of a uranium-bearing ore aquifer of sandstone uranium ore, and analyzing the core to obtain a core catalogue result; performing geophysical prospecting well logging on the uranium-bearing ore aquifer to obtain a well logging curve; determining distribution positions of high-permeability surrounding rock and low-permeability ore layers in the uranium-bearing ore aquifer according to the core logging result and the logging curve;
before collecting the core of the uranium-bearing uranium deposit aquifer of the sandstone uranium deposit, the method of this embodiment further includes: the construction of the vertical well is carried out by in-situ leaching uranium extraction, firstly, on-site drilling and drilling engineering is arranged according to the conventional uranium leaching requirement, namely, the drilling is carried out in a uranium-bearing water-bearing layer of sandstone uranium deposit, the drilling comprises a horizontal well and a vertical well, the arrangement of the vertical wells on a plane is in a determinant or five-point mode, the spacing between pumping and injecting holes (namely, a liquid pumping hole and an injecting hole, namely, a pumping well and an injecting well) is 25-30m, after the vertical well is drilled and uncovered through the whole uranium-bearing water-bearing layer at the arranged position, the drilling process of the drilling is completed, and the core containing the uranium deposit water-bearing layer is collected in the drilling which completes the drilling, and the physical detection well is carried out on the uranium-bearing water-bearing layer. After drilling is completed, a plastic well pipe with phi of 152 mm is lowered, cement is filled in an annulus between the drilling wall and the plastic well pipe by using a reverse grouting process, and a well cementation process is completed after the cement is solidified. The vertical well after well completion includes an injection well and a withdrawal well.
In this embodiment, the uranium-bearing ore aquifer refers to an aquifer in which a certain uranium ore layer is distributed in a sandy-leachable uranium deposit.
In S1, core collection is carried out on the whole uranium-bearing ore aquifer, and the core is a cylindrical rock sample taken from a drilled hole of a well by using an annular core bit and other coring tools according to geological exploration work or engineering requirements so as to collect and obtain the core of the uranium-bearing ore aquifer of the sandstone uranium deposit. Analysis of the core can be seen to: (1) the age, lithology and sedimentary character of the formation; (2) physical and chemical properties of the seam; (3) underground construction conditions (e.g., faults, joints, dip angles, etc.). And (3) scientifically and objectively recording and arranging original data inherent to the rock core obtained through analysis, and obtaining a rock core recording result.
And S1, performing geophysical prospecting well logging on the uranium-bearing ore aquifer to determine parameters such as density, three-side apparent resistivity, natural potential, natural gamma, current, sound waves and the like, further drawing to obtain a well logging curve, and analyzing and inverting lithology distribution, ore layer distribution and porosity/permeability vertical distribution characteristics of the uranium-bearing ore aquifer from top to bottom according to the well logging curve.
According to the method, distribution positions of the high-permeability surrounding rock and the low-permeability ore layer in the uranium-bearing ore aquifer can be determined according to the core logging result and the logging curve.
S2: cutting a sleeve and a cement sheath in a cutting section of the high-permeability surrounding rock for each high-permeability surrounding rock, and placing a built-in filter in the cutting section; injecting a temporary plugging agent into the uranium-bearing ore aquifer until the leaching agent flows only in the low permeability ore layer;
the present embodiment performs cut-and-fenestration on each highly permeable surrounding rock. For each high permeability surrounding rock, the method of the present embodiment further includes determining the cut segment of the high permeability surrounding rock prior to cutting the casing and cement sheath in the cut segment of the high permeability surrounding rock, which may include: judging whether the thickness of the surrounding rock with strong permeability is larger than or equal to a first set value; if yes, the cutting length is smaller than or equal to a first set value; if not, the cutting length is the thickness; the cutting section of the surrounding rock with strong permeability is determined based on the cutting length, and specifically, a region which is within the range of 5m above and below the low permeability ore layer and has the same length as the cutting length is taken as the cutting section. The first setting value of the present embodiment may be 5m, and at this time, the step of determining the cut segment includes: if the thickness of the high-permeability surrounding rock is greater than or equal to 5m, the cutting length is controlled within 5m, if the thickness of the high-permeability surrounding rock is less than 5m, the cutting length is consistent with the thickness, then the length of the cutting section is enabled to be equal to the cutting length, and the height is enabled to be equal to the range of the low-permeability ore layer and 5m above and below the low-permeability ore layer, so that the cutting section is determined. And cutting the sleeve and the cement sheath of the cutting section completely to expose the rock, and putting a corresponding built-in filter in the cutting section to serve as a flow channel of the solution and the temporary plugging agent.
The built-in filter of the embodiment can be a special in-well filter for in-situ leaching uranium, and can be a ring skeleton type PVC filter.
In S2, injecting the temporary plugging agent into the uranium containing ore aquifer until the leaching agent flows only in the low permeability ore layer may include:
(1) And injecting the tracer and the temporary plugging agent into the uranium-bearing ore aquifer, and simultaneously starting a liquid extraction system to obtain a first extracted liquid of the uranium-bearing ore aquifer.
The tracer of this embodiment may be an alcohol or a salt, and the salt may be sodium chloride or the like, so as to perform a tracer-based tracer test. The temporary plugging agent can be Cr 3+ HPAM gel composed of partially hydrolyzed polyacrylamide HPAM and Cr 3+ The gel with a three-dimensional grid structure is formed by the crosslinking reaction of the crosslinking agent.
In this embodiment, the tracer and the temporary plugging agent are synchronously injected into the uranium-bearing ore aquifer from the wellhead of the injection well through the pressurized liquid injection system, so as to accelerate the flow rate of groundwater in the uranium-bearing ore aquifer, and meanwhile, the liquid extraction system of the extraction well is started to obtain a first extraction liquid of the uranium-bearing ore aquifer.
(2) Analyzing the first extracting solution, and drawing a first change curve of the concentration of the tracer in the first extracting solution along with the time change and a second change curve of the concentration of the temporary plugging agent in the first extracting solution along with the time change; and determining a first time point when the peak value of the concentration of the tracer appears according to the first change curve, and determining a second time point when the peak value of the concentration of the temporary plugging agent appears according to the second change curve.
In this embodiment, the first extraction liquid may be sampled and analyzed once every hour, and of course, the first extraction liquid may be sampled and analyzed once at intervals of other durations, where the intervals may be set according to requirements. After each sampling analysis, recording the occurrence time and the concentration of the tracer and the temporary plugging agent in the first extracted liquid so as to facilitate the subsequent drawing of a change trend curve of the concentration of the tracer and the temporary plugging agent along with the time change, recording the occurrence time points of the concentration peak values of the tracer and the temporary plugging agent on the change trend curve, namely drawing to obtain a first change curve and a second change curve, and determining a first time point and a second time point. The peak refers to the peak that appears for the first time.
(3) Stopping the injection of the tracer after reaching the second time point, and continuing to inject the temporary plugging agent until the first time period is continued; stopping the injection and liquid extraction system of the temporary plugging agent, and enabling the temporary plugging agent to precipitate and solidify in the uranium-bearing ore water-containing layer for a second period of time.
In this embodiment, the first period of time may be 3 days, and the second period of time may be 7 days. And stopping the tracer injection after the concentration peak value of the temporary plugging agent appears, namely stopping the tracer test, and continuously maintaining the temporary plugging agent injection for 3 days. After the maintenance for 3 days, the temporary plugging agent is considered to wrap the uranium-containing ore water-bearing layer finally, the injection and pumping of the temporary plugging agent are stopped, and the temporary plugging agent is precipitated and solidified for 7 days under the natural condition in the uranium-containing ore water-bearing layer.
(4) And injecting the tracer into the uranium-bearing ore aquifer, and simultaneously starting the liquid extraction system to obtain a second extracted liquid of the uranium-bearing ore aquifer.
(5) Analyzing the second extraction liquid, and drawing a third change curve of the concentration of the tracer in the second extraction liquid along with the change of time; determining a third point in time at which a peak in the concentration of the tracer occurs from the third profile; after reaching the third point in time, the injection of the tracer and the extraction system is stopped.
(6) Judging whether the time interval between the first time point and the third time point is larger than a second set value or not; if so, the leaching agent only flows in the low permeability seam; if not, returning to the step of continuously injecting the temporary plugging agent until the first time period is continued.
In this embodiment, after the precipitation and solidification are performed for 7 days, a tracing test is performed again, a third time point when the peak value of the concentration of the tracer appears is determined, and the third time point when the peak value of the concentration of the tracer appears, which is determined by the first tracing test, is compared with the first time point when the peak value of the concentration of the tracer appears, so as to verify whether the temporary plugging agent has completed permeability control. If the time interval between the third time point and the first time point is greater than the second set value, the third time point of the tracer concentration peak value determined by carrying out the tracing test again is very late, or the tracer maintains a low concentration level for a long time, the long time can be the sum of the first time point and the second set value, and the time interval between the third time point and the first time point is the sum of the first time point and the second set value, the tracer concentration peak value determined by carrying out the tracing test again is not always present, the permeability of the surrounding rock with strong permeability is controlled, the temporary plugging agent is considered to be fully functional, and the leaching solution only flows in the low-permeability ore layer. Otherwise, the permeability of the surrounding rock with strong permeability is not controlled, and the temporary plugging agent injection needs to be continued.
In this example, the permeability of each highly permeable surrounding rock was controlled as described above. If the uranium-bearing aquifer of the embodiment contains two strong permeable surrounding rocks, one located at the upper part of the uranium-bearing aquifer and one located at the lower part of the uranium-bearing aquifer, the permeability control of the strong permeable surrounding rocks located at the lower part of the uranium-bearing aquifer may be performed first, and then the permeability control of the strong permeable surrounding rocks located at the upper part of the uranium-bearing aquifer may be performed.
S3: according to the thickness, shape and length of the uranium-bearing ore aquifer, horizontal well blasting or vertical well blasting is determined; if the horizontal well blasting is adopted, a horizontal well is directionally constructed in the low-permeability ore layer according to the ore body distribution of the low-permeability ore layer, and blasting fracturing of the low-permeability ore layer is carried out in the horizontal well; if the vertical well blasting is adopted, blasting fracturing of the low-permeability ore deposit is carried out in the vertical well.
In S3, determining whether to use horizontal well blasting or vertical well blasting according to the thickness, morphology and length of the uranium-bearing ore aquifer may include: the embodiment determines the spatial distribution characteristics of the uranium-bearing ore aquifer, such as thickness, morphology and occurrence, according to the results of the pre-geophysical well logging analysis. If the thickness of the uranium-containing ore aquifer is larger than a third set value (the third set value can be 10 m), the morphology is regular (such as the morphology is plate-shaped and the inclination angle is smaller (1-3 degrees)), and the length on the trend is larger than a fourth set value (the fourth set value can be 100 m), the horizontal well blasting is determined to be adopted; if the thickness of the uranium-containing ore aquifer is smaller than or equal to the third set value, the morphology is irregular (in other irregular shapes (such as coil head shape)), and the ore forming scale is smaller, namely the length is smaller than or equal to the fourth set value, horizontal well blasting is not adopted for cost reasons, and vertical well blasting is determined to be adopted.
In S3, performing explosive fracturing of the low permeability seam in the horizontal well may include: and (3) directionally constructing a horizontal well in the low-permeability ore layer, namely drilling the horizontal well in the low-permeability ore layer to obtain a horizontal section, wherein the horizontal section penetrates through the whole low-permeability ore layer along the trend of the ore body, and the projection of the horizontal section on the horizontal plane is S-shaped. The fracturing devices are arranged at intervals in the horizontal section so as to perform interval blasting fracturing in the low-permeability ore layer. Specifically, the embodiment develops directional drilling of the horizontal well in the low permeability ore layer, the directional drilling of the horizontal well requires advancing along the advancing direction of the uranium-bearing ore aquifer and penetrating through the whole low permeability ore layer, and the horizontal well advances in an S shape to ensure the maximum blasting effect. In this embodiment, the fracturing devices may be arranged at intervals of 30m, that is, as shown in fig. 2, fig. 2 (a) is a schematic plan view of horizontal well blasting, and fig. 2 (b) is a schematic three-dimensional perspective view of horizontal well blasting. In the horizontal section, the fracturing device is gradually put into a low-permeability ore layer, and the fracturing device is arranged at intervals of 30m, namely, every 30m is subjected to blasting fracturing.
In S3, performing explosive fracturing of the low permeability seam in the vertical well may include: determining a vertical section of the vertical well corresponding to the low permeability seam; the fracturing devices are spaced apart within the vertical section for spaced apart blasting fracturing in the low permeability seam. Specifically, as shown in fig. 3, when a vertical well is used to directly blast a low permeability seam, the fracturing devices are arranged at intervals along the vertical direction of the vertical section so as to perform interval blasting fracturing in the low permeability seam.
Starting from a low permeability seam, intermittent fracturing should produce micro cracks rather than long straight cracks after fracturing. The method of this embodiment therefore further comprises, after performing the interval blast fracturing in the low permeability seam:
(1) And injecting the tracer into the uranium-bearing ore aquifer, and simultaneously starting the liquid extraction system to obtain a third extracted liquid of the uranium-bearing ore aquifer.
(2) Analyzing the third extract, and drawing a fourth change curve of the concentration of the tracer in the third extract along with the change of time; determining a fourth point in time at which a peak in the concentration of the tracer occurs according to the fourth variation curve; after reaching the fourth point in time, the injection of the tracer and the extraction system are stopped.
(3) Judging whether the time interval between the third time point and the fourth time point corresponding to the leaching agent only when the low permeability ore layer flows is smaller than a fifth set value or not; if not, injecting the temporary plugging agent into the uranium-bearing ore aquifer, starting the liquid extraction system at the same time until the first time period is continued, stopping the injection of the temporary plugging agent and the liquid extraction system, enabling the temporary plugging agent to precipitate and solidify in the uranium-bearing ore aquifer for a second time period, and returning the step of injecting the tracer into the uranium-bearing ore aquifer, starting the liquid extraction system at the same time, and obtaining a third extracted liquid of the uranium-bearing ore aquifer.
In the embodiment, after the blasting fracturing of the low-permeability ore layer is completed, a tracing test is carried out, and compared with the result of the early tracing test, whether the blasting generates enough cracks in the low-permeability ore layer is verified. If the fourth time point is closer to the third time point of the last time in the early-stage tracing test, that is, the time interval between the fourth time point and the third time point is smaller than the fifth set value, the situation that enough cracks are generated in blasting and the phenomenon that long straight cracks conduct the pumping and injecting liquid well does not exist is indicated, and at the moment, the method of the embodiment is ended, and normal in-situ leaching uranium pumping and injecting exploitation can be carried out. If not, the existence of a long straight crack forms a new strong permeation zone, after the micro-fracturing operation (namely blasting fracturing) of the low-permeability ore layer is finished, the strong permeation zone and other high-permeability channels generated by the fracturing process are required to be plugged, at the moment, the prepared temporary plugging agent is injected into the uranium-bearing ore water-bearing layer from a wellhead through a pressurizing liquid injection system, and meanwhile, a liquid extraction system of a hole is started, so that the temporary plugging agent is precipitated and solidified under natural conditions, the strong permeation zone plugging is realized, until leaching liquid flows only in the low-permeability ore layer, and normal in-situ leaching uranium extraction and injection exploitation can be carried out. At this time, due to the decrease of the permeability of the strong permeable zone and the increase of the permeability of the low permeable zone, the solution is uniformly distributed in the range of the groundwater flow field in the uranium-bearing ore water-bearing layer, and the corresponding uranium concentration of the leaching solution is relatively high.
Aiming at the strong non-uniformity and low permeability sandstone uranium ores with high thickness and stability, the embodiment provides a method for adjusting the flow range of leaching solution for leaching in situ of sandstone uranium ores, so as to improve the non-uniformity and the recovery ratio, adopts a permeation increasing means to improve the permeability of a low permeability zone, adopts a temporary plugging agent to plug the strong permeability zone, reduces the permeability of the strong permeability zone, reduces the overall permeability difference of underground strata, improves the sweep range of underground water in the water-bearing layer of the non-uniformity uranium ores, prevents channeling, enables leaching agents to enter an ore layer to the greatest extent, and further enables the ore layer to be fully leached and improves the recovery ratio of the sandstone uranium ores. According to the embodiment, the mode of fracturing and temporary plugging agent can be used, so that the permeability of a low-permeability zone in the uranium-bearing ore water-bearing layer is improved, the permeability of a strong-permeability zone is reduced, the uniformity of the permeability of the underground uranium-bearing ore water-bearing layer is ensured, the solution is ensured to cover the uranium-bearing ore water-bearing layer to the greatest extent, the leaching solution sweep range and efficiency are improved, and finally the uranium-bearing ore leaching efficiency is improved.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.

Claims (10)

1. A method of expanding the reach of a leaching solution for sandstone uranium ores in situ, the method comprising:
collecting a core of a uranium-bearing ore aquifer of sandstone uranium ore, and analyzing the core to obtain a core catalogue result; performing geophysical prospecting well logging on the uranium-bearing ore aquifer to obtain a well logging curve; determining distribution positions of high-permeability surrounding rock and low-permeability ore layers in the uranium-bearing ore aquifer according to the core logging result and the logging curve;
cutting a sleeve and a cement sheath in a cutting section of the high-permeability surrounding rock for each high-permeability surrounding rock, and placing a built-in filter in the cutting section; injecting a temporary plugging agent into the uranium-bearing ore aquifer until the leaching agent flows only in the low permeability ore layer;
according to the thickness, shape and length of the uranium-bearing ore aquifer, horizontal well blasting or vertical well blasting is determined; if the horizontal well blasting is adopted, a horizontal well is directionally constructed in the low-permeability ore layer according to the ore body distribution of the low-permeability ore layer, and blasting fracturing of the low-permeability ore layer is carried out in the horizontal well; if the vertical well blasting is adopted, blasting fracturing of the low-permeability ore deposit is carried out in the vertical well.
2. The method of claim 1, wherein prior to the collecting the core of the uranium-bearing aquifer of sandstone uranium ores, the method further comprises: and arranging drilling holes and drilling the drilling holes in the uranium-bearing ore aquifer of the sandstone uranium ore according to the on-site leaching uranium extraction requirement, so as to collect the core of the uranium-bearing ore aquifer in the drilling holes with the drilling holes completed and perform geophysical prospecting on the uranium-bearing ore aquifer.
3. The method according to claim 1, characterized in that before said cutting of casing and cement sheath in the cut section of the high permeability surrounding rock, the method further comprises determining the cut section of the high permeability surrounding rock, in particular comprising:
judging whether the thickness of the surrounding rock with strong permeability is larger than or equal to a first set value;
if yes, the cutting length is smaller than or equal to the first set value;
if not, the cutting length is the thickness;
determining a cut segment of the highly permeable surrounding rock based on the cut length.
4. The method according to claim 1, wherein the temporary plugging agent is Cr 3+ HPAM gel.
5. The method according to claim 1, characterized in that said injecting a temporary plugging agent into said uranium containing ore aquifer until the leaching agent flows only in said low permeability ore layer comprises in particular:
injecting a tracer and a temporary plugging agent into the uranium-bearing ore aquifer, and simultaneously starting a liquid extraction system to obtain a first extracted liquid of the uranium-bearing ore aquifer;
analyzing the first extract, and drawing a first change curve of the concentration of the tracer in the first extract with time and a second change curve of the concentration of the temporary plugging agent in the first extract with time; determining a first time point when the peak value of the concentration of the tracer appears according to the first change curve, and determining a second time point when the peak value of the concentration of the temporary plugging agent appears according to the second change curve;
stopping the injection of the tracer after reaching the second time point, and continuing to inject the temporary plugging agent until the first time period is reached; stopping the injection of the temporary plugging agent and the liquid extraction system, and enabling the temporary plugging agent to precipitate and solidify in the uranium-bearing ore water-containing layer for a second time period;
injecting the tracer into the uranium-bearing ore aquifer, and simultaneously starting the liquid extraction system to obtain a second extracted liquid of the uranium-bearing ore aquifer;
analyzing the second extract, and drawing a third change curve of the concentration of the tracer in the second extract along with the change of time; determining a third point in time at which a peak in the concentration of the tracer occurs from the third profile; stopping the injection of the tracer and the extraction system after reaching the third point in time;
judging whether the time interval between the first time point and the third time point is larger than a second set value or not; if so, the leaching agent flows only in the low permeability seam; if not, returning to the step of continuously injecting the temporary plugging agent until the first time period is continued.
6. The method of claim 5, wherein the tracer is an alcohol or salt; the first period of time is 3 days; the second period of time is 7 days.
7. The method according to claim 1, characterized in that said determining, according to the thickness, morphology and length of the uranium-containing ore aquifer, whether to use horizontal well blasting or vertical well blasting comprises in particular:
if the thickness of the uranium-bearing ore aquifer is larger than a third set value, the morphology is regular, and the length is larger than a fourth set value, horizontal well blasting is determined to be adopted;
and if the thickness of the uranium-containing ore aquifer is smaller than or equal to the third set value, the morphology is irregular, and the length is smaller than or equal to the fourth set value, determining to adopt vertical well blasting.
8. The method of claim 1, wherein the performing blast fracturing of the low permeability seam in the horizontal well specifically comprises:
spacing fracturing devices in a horizontal section of the horizontal well to perform spaced blasting fracturing in the low permeability ore layer; the horizontal segment penetrates through the low-permeability ore layer along the trend of the ore body, and the projection of the horizontal segment on the horizontal plane is S-shaped.
9. The method according to claim 1, wherein said performing blasting fracturing of said low permeability seam in a vertical well comprises:
determining a vertical section of a vertical well corresponding to the low permeability seam; and arranging fracturing devices at intervals in the vertical section so as to perform interval blasting fracturing in the low-permeability ore layer.
10. The method of claim 5, wherein after performing blast fracturing of the low permeability seam, the method further comprises:
injecting the tracer into the uranium-bearing ore aquifer, and simultaneously starting the liquid extraction system to obtain a third extracted liquid of the uranium-bearing ore aquifer;
analyzing the third extract, and drawing a fourth change curve of the concentration of the tracer in the third extract along with the change of time; determining a fourth point in time at which a peak in the concentration of the tracer occurs according to the fourth variation curve; stopping the injection of the tracer and the liquid extraction system after reaching the fourth time point;
determining whether a time interval between the third time point and the fourth time point corresponding to when the leaching agent flows only in the low permeability ore layer is less than a fifth set value; if not, injecting the temporary plugging agent into the uranium-containing ore aquifer, starting the liquid extraction system at the same time until the first time period is continued, stopping the injection of the temporary plugging agent and the liquid extraction system, enabling the temporary plugging agent to precipitate and solidify in the uranium-containing ore aquifer for the second time period, and returning the step of injecting the tracer into the uranium-containing ore aquifer, starting the liquid extraction system at the same time, and obtaining a third extracted liquid of the uranium-containing ore aquifer.
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