阅读说明：本技术 砂岩型铀矿层的增渗方法 (Permeation increasing method for sandstone-type uranium ore layer ) 是由 王伟 张明涛 苏学斌 王奇智 张思怡 常江芳 周根茂 李召坤 于 2021-01-21 设计创作，主要内容包括：本发明适用于铀矿开采技术领域,公开了一种砂岩型铀矿层的增渗方法。上述砂岩型铀矿层的增渗方法包括：采用爆破增渗的方法,使所述砂岩型铀矿床的赋矿岩层中产生微小裂隙；采用酸化增渗的方法,溶解产生所述微小裂隙的赋矿岩层中的无用矿物。本发明首先通过爆破增渗的方法初次提高赋矿岩层的渗透性,可以在赋矿岩层中产生大量微小裂隙,避免产生大的裂隙,符合地浸开采的要求,能够在砂岩型铀矿层渗透性改造中直接应用,同时为酸化增渗提供必要的空间,进而通过酸化增渗的方法,进一步提高赋矿岩层的渗透性,同时可以提高采铀工艺的开采效率,使低渗透砂岩型铀矿资源得以顺利开采和利用。(The invention is suitable for the technical field of uranium ore mining and discloses a permeability increasing method for a sandstone-type uranium ore layer. The permeability increasing method for the sandstone-type uranium ore layer comprises the following steps: a blasting permeation-increasing method is adopted to generate micro cracks in an orexigenic rock layer of the sandstone-type uranium deposit; and (3) dissolving useless minerals in the orexigenic rock stratum generating the micro fractures by adopting an acidification and infiltration increasing method. The permeability of the orexigenic rock stratum is firstly improved by the blasting permeation-increasing method, a large number of micro cracks can be generated in the orexigenic rock stratum, the generation of large cracks is avoided, the requirement of ground leaching exploitation is met, the method can be directly applied to permeability improvement of the sandstone-type uranium ore stratum, meanwhile, a necessary space is provided for acidification permeation-increasing, further, the permeability of the orexigenic rock stratum is further improved by the acidification permeation-increasing method, meanwhile, the exploitation efficiency of a uranium mining process can be improved, and low-permeability sandstone-type uranium ore resources can be successfully exploited and utilized.)

1. A permeability increasing method for a sandstone-type uranium ore layer is characterized by comprising the following steps:

a blasting permeation-increasing method is adopted to generate micro cracks in an orexigenic rock layer of the sandstone-type uranium deposit;

and (3) dissolving useless minerals in the orexigenic rock stratum generating the micro fractures by adopting an acidification and infiltration increasing method.

2. The method for permeability enhancement of a sandstone-type uranium ore layer according to claim 1, wherein the method for permeability enhancement by blasting is used for creating microfractures in an orexigenic rock layer of the sandstone-type uranium ore deposit, and comprises:

acquiring geological information of an orexigenic rock stratum of a sandstone-type uranium deposit, and determining the position and the direction of a horizontal well according to the geological information of the orexigenic rock stratum;

forming a horizontal well according to the position and the trend of the horizontal well, and arranging an explosive package in the horizontal well;

detonating an explosive charge within the horizontal well to create micro-fractures in the mineralized rock formation.

3. The method for enhancing permeability of a sandstone-type uranium ore layer according to claim 2, wherein a horizontal portion of the horizontal well is provided in a middle portion of the orexigenic rock layer.

4. The method for enhancing infiltration of a sandstone-type uranium ore layer according to claim 2, wherein the placing of an explosive charge within the horizontal well comprises:

and arranging explosive packages in the horizontal well in a structure form of uncoupled charging and indirect charging by adopting a drill rod jacking charging mode, and filling stemming between adjacent explosive packages.

5. The method for enhancing permeability of a sandstone-type uranium ore layer according to claim 4, wherein the structural form of the uncoupled charge has a decoupling coefficient in a range from 1.5 to 3;

the indirect charge being of a construction in which the spacing L between adjacent charges is₂Is 2/3L₁(ii) a Wherein L is₁Is the equivalent thickness of the mineralized formation.

6. The method for enhancing permeability of a sandstone-type uranium ore layer according to claim 2, wherein the initiating of an explosive charge in the horizontal well comprises:

and sequentially detonating explosive charges in the horizontal well according to the sequence from near to far away from the wellhead of the horizontal well by adopting a differential blasting method.

7. The method for permeation enhancement of a sandstone-type uranium ore layer according to claim 6, wherein the differential blasting method has a differential time in a range from 25ms to 50 ms.

8. The method for cementation of uranium deposits of the sandstone type according to any of claims 1 to 7, wherein said method for cementation by acidification comprises the steps of:

determining an acidizing and permeability-increasing agent according to the mineral components of the orexigenic rock stratum;

and opening a vertical well, and injecting the acidizing and permeability-increasing agent into the mineral-bearing stratum which generates the micro fractures from the vertical well so as to dissolve useless minerals in the mineral-bearing stratum.

9. The method of permeation enhancement of a sandstone-type uranium ore layer according to claim 8, wherein the vertical wells comprise a liquid injection well and a liquid extraction well; the liquid injection well and the liquid extraction well are both provided with a perforation at the position of the orexigenic rock stratum;

and the acidizing and permeability-increasing agent is injected into the mineral-forming rock stratum generating the micro cracks through the perforation of the liquid injection well, and the mineral-forming rock stratum is extracted through the perforation of the liquid extraction well.

10. The permeability increasing method for a sandstone-type uranium ore layer according to claim 9, wherein the liquid extraction well is provided with a filter screen inside the perforation of the liquid extraction well, and the liquid extraction well is provided with quartz sand outside the perforation of the liquid extraction well.

Technical Field

The invention belongs to the technical field of uranium ore mining, and particularly relates to a permeability increasing method for a sandstone-type uranium ore layer.

Background

Sandstone-type uranium ores are the most important natural uranium resource types in China, and the preferred mining mode is an in-situ leaching process, which is called 'in-situ leaching' for short. The uranium mining method integrating mining and smelting aims at uranium deposits which exist in a pressure-bearing water-containing sandstone layer and have good permeability, dissolves uranium in ores under a natural burial condition through drilling engineering and by means of chemical reagents, and has obvious environmental protection advantages. In actual production, the endowing rock stratum has certain permeability, which is a basic requirement and a key control factor for ground leaching exploitation, so how to effectively improve the permeability of the endowing rock stratum of the low-permeability sandstone uranium ore becomes a key difficult problem facing the exploitation of the resources at present, and a solution is needed urgently.

The main purpose of the methods is to form a plurality of long cracks around a drilling well and form a crack network with the original natural weak surface of the rock stratum, so that the long cracks become a gathering channel of oil and gas, and the oil and gas recovery efficiency is improved by utilizing the high flow conductivity of the long cracks. However, according to the requirements of the ground leaching mining process, a long crack with a remarkable geometric size cannot be generated in the uranium reservoir permeability improvement process, so that the phenomena that the ground leaching mining fails due to the occurrence of the dominant flow of leaching liquid are avoided, and therefore, the physical infiltration increasing technologies cannot be directly applied to permeability transformation of sandstone-type uranium deposit.

Disclosure of Invention

In view of this, the embodiment of the invention provides a permeability increasing method for a sandstone-type uranium ore layer, so as to solve the problem that the prior art cannot be directly applied to permeability improvement of the sandstone-type uranium ore layer.

The embodiment of the invention provides a permeability increasing method for a sandstone-type uranium ore layer, which comprises the following steps:

the method of blasting permeation increase is adopted to generate micro cracks in the ore-bearing rock layer of the sandstone-type uranium deposit;

and (3) dissolving useless minerals in the orexigenic rock stratum generating micro fractures by adopting an acidification and infiltration increasing method.

Optionally, the method for enhancing permeability by blasting is used for generating micro cracks in an orexigenic rock layer of the sandstone-type uranium deposit, and comprises the following steps:

acquiring geological information of an orexigenic rock layer of the sandstone-type uranium deposit, and determining the position and the direction of a horizontal well according to the geological information of the orexigenic rock layer;

arranging a horizontal well according to the position and the trend of the horizontal well, and arranging an explosive package in the horizontal well;

and detonating the explosive charge in the horizontal well to generate micro cracks in the ore-bearing rock layer.

Optionally, the horizontal portion of the horizontal well is disposed in a middle portion of the demineralized rock formation.

Optionally, an explosive charge is disposed within the horizontal well, comprising:

the method is characterized in that explosive charges are arranged in a horizontal well in a structure form of uncoupled charging and indirect charging by adopting a drill rod pushing charging mode, and stemming is filled between adjacent explosive charges.

Optionally, the structural form of the uncoupled charge has a decoupling coefficient in the range of 1.5 to 3;

in indirect-charge constructions, the spacing L between adjacent charges₂Is 2/3L₁(ii) a Wherein L is₁To give the equivalent thickness of the rock formation.

Optionally, detonating an explosive charge within a horizontal well, comprising:

and (3) sequentially detonating explosive packages in the horizontal well according to the sequence from near to far away from the well mouth of the horizontal well by adopting a differential blasting method.

Alternatively, the differential time of the differential blasting method ranges from 25ms to 50 ms.

Optionally, the method of acidizing and permeability increasing is used for dissolving useless minerals in the orexigenic rock formation which generates micro fractures, and comprises the following steps:

determining an acidification permeability-increasing agent according to mineral components of the orexification rock stratum;

and (3) opening a vertical well, and injecting an acidizing and permeability-increasing agent into the mineral-bearing stratum which generates micro fractures from the vertical well so as to dissolve useless minerals in the mineral-bearing stratum.

Optionally, the vertical well comprises a fluid injection well and a fluid extraction well; the liquid injection well and the liquid extraction well are provided with perforations at the positions of the orexigenic rock layers;

and the acidizing and permeability-increasing agent is injected into the mineral-bearing rock stratum with tiny cracks through the perforation of the liquid injection well, and the mineral-bearing rock stratum is extracted through the perforation of the liquid extraction well.

Optionally, the liquid extraction well is provided with a filter screen inside the perforation of the liquid extraction well, and the liquid extraction well is provided with quartz sand outside the perforation of the liquid extraction well.

Compared with the prior art, the embodiment of the invention has the following beneficial effects: according to the embodiment of the invention, the permeability of the orexigenic rock stratum is improved by the blasting permeation-increasing method, a large number of micro cracks can be generated in the orexigenic rock stratum, the generation of large cracks is avoided, the requirement of ground leaching exploitation is met, the method can be directly applied to permeability improvement of the sandstone-type uranium ore stratum, meanwhile, a necessary space is provided for acidification permeation-increasing, further, the permeability of the orexigenic rock stratum is further improved by the acidification permeation-increasing method, meanwhile, the exploitation efficiency of a uranium mining process can be improved, and low-permeability sandstone-type uranium ore resources can be successfully exploited and utilized.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic flow chart of an implementation of a permeability increasing method for a sandstone-type uranium deposit according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the overall arrangement of blast infiltration augmentation provided by an embodiment of the present invention;

fig. 3 is a schematic diagram of the overall arrangement of acidification and infiltration promotion provided by an embodiment of the present invention.

In the figure: 1. horizontal wells; 2. a drill stem; 3. a low permeability rock formation; 4. an explosive package; 5. endowing an ore stratum; 6. a liquid pumping well; 7. a filter screen; 8. a liquid injection well; 9. PVC pipes; 10. concrete; 11. quartz sand; 12. and (6) perforating.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

In order to explain the technical means of the present invention, the following description will be given by way of specific examples.

Fig. 1 is a schematic flow chart of an implementation of a permeability increasing method for a sandstone-type uranium deposit according to an embodiment of the present invention, and for convenience of description, only a part related to the embodiment of the present invention is shown.

Referring to fig. 1 and 2, the method may include the steps of:

s101: the method of blasting permeation increase is adopted to generate micro cracks in the ore-bearing rock layer 5 of the sandstone-type uranium deposit.

S102: and (3) dissolving useless minerals in the ore-bearing rock stratum 5 with micro cracks by adopting an acidification and infiltration increasing method.

In an embodiment of the invention, the sandstone-type uranium deposit is a low permeability sandstone-type uranium deposit. Firstly, a blasting permeation-increasing method and a physical permeation-increasing method are adopted, a large number of communicated micro cracks can be generated in the ore-bearing rock layer 5, so that the permeability of a uranium reservoir layer can be improved to a certain degree, the blasting permeation-increasing method can avoid large cracks from being generated in the ore-bearing rock layer 5, and the requirements of in-situ leaching exploitation are met. And then, on the basis of blasting permeation enhancement, chemically increasing the permeation of the orexigenic rock layer 5 through acidification permeation enhancement, so that the exploitation efficiency of the in-situ leaching uranium exploitation process is improved, and low-permeation sandstone type uranium ore resources can be successfully exploited and utilized.

The method for acidification and permeation enhancement is adopted, so that clay, clay cement, mineral particles and powder generated in blasting permeation enhancement and the like in the mineralization of uranium ores, which are useless minerals for uranium ore mining, can be dissolved, and the permeability of the mineralization rock layer 5 can be further improved on the basis of blasting permeation enhancement.

In an embodiment of the present invention, referring to fig. 2, the above S101 may include the following steps:

acquiring geological information of an ore-bearing rock layer 5 of a sandstone-type uranium deposit, and determining the position and the direction of a horizontal well according to the geological information of the ore-bearing rock layer 5;

a horizontal well 1 is arranged according to the position and the trend of the horizontal well, and an explosive package 4 is arranged in the horizontal well 1;

the explosive charges 4 in the horizontal well 1 are detonated to create micro-fractures in the oregenic rock formation 5.

In the embodiment of the invention, the geological information of the ore-bearing rock layer 5 of the sandstone-type uranium deposit can be determined by analyzing the stratum distribution, the ore-bearing sand body occurrence, the argillaceous interlayer, the ore body distribution and other basic geological data and combining with the sandstone-type uranium deposit description data to fully master the field engineering geological condition, and the geological information can comprise specific position, trend, thickness and the like, so as to determine the position and trend of the horizontal well 1, wherein the horizontal well 1 is generally arranged at the middle position of the ore-bearing rock layer 5 along the trend of the ore-bearing rock layer. And according to the horizontal well construction technology, completing the construction of the horizontal well 1 according to the horizontal well 1 and the horizontal well trend.

The selection of the explosive, the calculation of the loading amount, the interval of the explosive packages 4 in the horizontal well 1 and the like can be determined according to the geological information of the ore-bearing rock stratum 5.

Explosives with superior resistance to water pressure and moderate detonation velocity are generally chosen, such as: emulsion explosives, colloidal explosives, and the like.

The geological information can also comprise information such as porosity, permeability, tensile strength, uranium content and other mineral components and contents of a sampling measured core, so as to measure the necessity of blasting permeability increase of an ore bed, estimate the charge amount and the like.

In one embodiment of the invention, referring to fig. 2, the horizontal portion of the horizontal well 1 is provided in the middle of the demineralised rock formation 5.

It should be understood here that the oregano layer 5 does not necessarily have only one horizontal well 1, and since the projection range of the oregano layer 5 on the horizontal plane is actually a two-dimensional area, one horizontal well 1 may not satisfy the purpose of permeability enhancement of the oregano layer 5, so that 3 to 6 horizontal well 1 combinations distributed radially with the central position of the oregano layer 5 as the center may be opened in the oregano layer 5.

In one embodiment of the invention, referring to fig. 2, the arrangement of the explosive charge 4 in the horizontal well 1 comprises:

the explosive charges 4 are arranged in the horizontal well 1 in a structure form of uncoupled charge and indirect charge by adopting a drill rod pushing charge mode, and stemming is filled between the adjacent explosive charges 4.

In one embodiment of the invention, the structural form of the uncoupled charge has an uncoupling coefficient in the range of 1.5 to 3;

in the form of indirect-charge construction, the spacing L between adjacent charges 4₂Is 2/3L₁(ii) a Wherein L is₁To give the equivalent thickness of the rock formation 5.

The explosive protecting cylinder is connected with the front end of the drill bit after the drill bit is drilled, the explosive protecting cylinder is required to have good rigidity, and the explosive protecting cylinder is jacked into the appropriate position of the horizontal well 1 again by the drill rod 2 for a plurality of times continuously.

In the embodiment of the invention, when the construction of the horizontal well 1 is completed, the explosive package is filled by L by adopting a drill rod pushing explosive charging method₂The interval is horizontally arranged in the horizontal well 1 along the direction of the horizontal well 1, the structural form of charging adopts uncoupled charging and indirect charging, the uncoupled coefficient k is controlled between 1.5 and 3, and the interval of the indirect charging is L₂And the explosive charges are filled with stemming to increase the transverse propagation strength of the explosion stress wave. In order to avoid the property change of the explosive under high hydrostatic pressure, a medicine package structure of a sealed PVC sleeve or a metal pipe is adopted, and a water pressure sealing test is carried out. Wherein, the stemming is filled by adopting a drill rod 2 pushing method.

According to the test result of the physical model, when L is₂＝2/3L₁Better infiltration increasing effect is obtained. Note that, since the thickness of each site of the demineralization rock layer 5 may be different, the equivalent thickness of the demineralization rock layer 5 is used here.

In an embodiment of the present invention, the above-mentioned detonating explosive package 4 in the horizontal well 1 comprises:

and (3) sequentially detonating the explosive charges 4 in the horizontal well 1 according to the sequence from near to far away from the well mouth of the horizontal well 1 by adopting a differential blasting method.

In one embodiment of the present invention, the differential blasting method has a differential time ranging from 25ms to 50 ms.

And (3) blasting and hole sealing, specifically, sequentially blasting explosive bags 4 in the horizontal well 1 by a differential blasting method, wherein the blasting direction is from near to far away from the well mouth of the horizontal well 1, and the differential time is controlled within the range of 25-50 milliseconds. The sectional blasting infiltration increasing method for the horizontal well 1 enables the energy of explosion to be fully utilized, a large number of communicated micro fracture networks can be generated in the orexigenic rock stratum 5, the generation of the dominant flow of the grown fractures is avoided, and the permeability of the orexigenic rock stratum 5 can be improved to a certain extent. The blasting hole sealing can ensure that the explosive gas does not escape, increase the effective action time and fully utilize the 'air wedge' action to penetrate through the crack net.

In an embodiment of the present invention, referring to fig. 3, the above S102 may include the following steps:

determining an acidification permeability-increasing agent according to mineral components of the orexification rock stratum 5;

and (3) opening a vertical well, and injecting an acidizing and permeability-increasing agent into the ore-bearing rock layer 5 which generates micro cracks from the vertical well so as to dissolve useless minerals in the ore-bearing rock layer 5.

Illustratively, when the main components of the clay, clay cement and mineral particles and powders produced in blasting infiltration are calcite and montmorillonite, hydrochloric acid is selected as the main acid, and a pad surfactant and required additives are provided as the acidizing infiltration agent. The main permeation mechanism is as follows:

CaCO₃+2HCl→CaCl₂+H₂O+CO₂↑

Fe(OH)₃+3HCl→FeCl₃+3H₂O

Al₂Si₂H₄O₉+18H⁺+18RF→2H₂SiF₆+2AlF₃+9H₂O+18R⁺

alternatively, the vertical well may extend through the mineralized rock formation 5.

In one embodiment of the invention, referring to fig. 3, the vertical well comprises a fluid injection well 8 and a fluid extraction well 6; the liquid injection well 8 and the liquid pumping well 6 are both provided with a perforation 12 at the position of the ore-bearing rock layer 5;

the acidizing and permeability-increasing agent is injected into the mineral-bearing rock layer 5 which generates tiny cracks through the perforation holes 12 of the liquid injection well 8, and the mineral-bearing rock layer 5 is extracted through the perforation holes 12 of the liquid extraction well 6.

Referring to fig. 3, the liquid injection well 8 and the liquid extraction well 6 are partially positioned in the mineral-bearing stratum 5, and the part positioned in the mineral-bearing stratum 5 is provided with a perforation 12, so that acidizing and permeability-increasing agents can be injected into the mineral-bearing stratum 5, and the solution after chemical reaction is extracted through the liquid extraction well 6.

In an embodiment of the present invention, an acidizing fluid enhancing agent may be injected into the injection well 8 from the injection well, i.e., the beginning of the injection well 8, such that the acidizing fluid enhancing agent is injected into the fractured mineral formation 5 from the perforations 12 of the injection well 8, wherein the fractures provide the necessary permeability and interpore connectivity for acidizing fluid enhancement

The acidizing permeation enhancer can dissolve clay, clay cement, mineral particles, powder and other minerals in the oregano rock layer 5, so that the permeability of the uranium ore layer is further improved on the basis of blasting permeation enhancement.

In one embodiment of the invention, referring to fig. 3, the extraction well 6 is provided with a screen 7 inside its perforations 12 and the extraction well 6 is provided with quartz sand 11 outside its perforations 12.

Wherein, the filter screen 7 and the quartz sand 11 can both play a role in filtering impurities and prevent from blocking cracks.

Alternatively, referring to fig. 3, concrete 10 and quartz sand 11 are respectively arranged outside the liquid injection well 8 at the joint position of the low-permeability rock layer 3 and the mineral-bearing rock layer 5 of the liquid injection well 8, wherein the concrete 10 is arranged in the low-permeability rock layer 3 for reinforcement, and the quartz sand 11 is arranged in the mineral-bearing rock layer 5 for impurity purification. Wherein, the liquid injection well can be made of PVC pipes 9.

And concrete 10 is arranged outside the liquid pumping well 6 at the joint position of the low-permeability rock stratum 3 and the upper layer of the liquid pumping well 6, so that the reinforcing effect is achieved.

It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiments provided in the present application, it should be understood that the disclosed method can be implemented in other ways.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.