CN-121976782-A - Drilling water-soluble exploitation method and system for deep novel polyhalite potassium salt mine

CN121976782ACN 121976782 ACN121976782 ACN 121976782ACN-121976782-A

Abstract

The invention discloses a drilling water-soluble mining method and system for deep novel polyhalite potassium salt ores, which are used for obtaining a target soluble mining level of novel polyhalite potassium salt ore bodies in a mining area, constructing a first vertical shaft, a second vertical shaft and a horizontal butt joint well in the mining area, drilling the first vertical shaft and the second vertical shaft to the target soluble mining level, arranging the horizontal butt joint well in the target soluble mining level and communicating the first vertical shaft and the second vertical shaft, carrying out grooving operation after drilling construction is completed to obtain a stable soluble cavity, injecting fresh water from the first vertical shaft, further dissolving the cavity wall of the integral soluble cavity by the injected fresh water, extracting generated potassium-containing brine from the second vertical shaft, conveying the potassium-containing brine to a potassium salt production workshop, and carrying out production monitoring by utilizing a monitoring system in the water injection and brine production process, and dynamically adjusting and optimizing injection and production parameters according to monitoring results. The invention realizes the green and efficient exploitation of deep novel polyhalite potassium salt ores.

Inventors

LIN YONGJIE
ZHENG MIANPING
ZHANG YONGSHENG
GUI BAOLING
SU KUI

Assignees

中国地质科学院矿产资源研究所

Dates

Publication Date: 20260505
Application Date: 20260123

Claims (10)

1. The drilling water-soluble exploitation method of the deep novel polyhalite potassium salt mine is characterized by comprising the following steps of: Step one, obtaining a target solution mining horizon (200) of a novel polyhalite potassium salt ore body in an ore region; Constructing a first vertical shaft (1), a second vertical shaft (2) and a horizontal butt joint well (3) in a mining area, drilling the first vertical shaft (1) and the second vertical shaft (2) to the target solution mining horizon (200), and arranging the horizontal butt joint well (3) in the target solution mining horizon (200) and communicating the first vertical shaft (1) and the second vertical shaft (2); thirdly, after drilling construction is completed, groove construction operation is carried out, and a stable-state solution cavity is obtained; And fourthly, injecting fresh water from the first vertical shaft (1), further dissolving the cavity wall of the integral dissolving cavity by the injected fresh water, extracting generated potassium-containing brine from the second vertical shaft (2), and conveying the potassium-containing brine to a potassium salt production workshop, and meanwhile, carrying out production monitoring by utilizing a monitoring system in the water injection and brine production process, and dynamically adjusting and optimizing injection and production parameters according to a monitoring result.
2. The method for drilling and water-soluble exploitation of deep new polyhalite potassium ore according to claim 1, wherein in the third step, a monitoring system is arranged at the initial stage of the trench construction, and the method specifically comprises the following steps: and a portable lithium potassium analyzer (4) is arranged at the wellhead of the first vertical shaft (1) and the wellhead of the second vertical shaft (2), and a sonar detector (5) is arranged in an initial solution cavity formed by initial water injection in the groove construction operation.
3. The method for mining deep novel polyhalite potassium salt mine by drilling water solution according to claim 2, wherein after the arrangement of a monitoring system is completed, fresh water is continuously injected into a first vertical shaft (1) and a second vertical shaft (2) to expand an initial solution cavity, a sonar detector (5) is used for monitoring the expansion condition of a reaction solution cavity in real time, a solution cavity development three-dimensional dynamic model is built, until a solution cavity stable state is reached, and the groove building operation is completed.
4. The drilling water-soluble exploitation method of deep novel polyhalite potassium salt mine according to claim 3, wherein the state of the solution cavity is dynamically monitored based on sonar data acquired by a sonar detector (5) and potassium ion concentration and flowback brine density data acquired by a portable lithium potassium analyzer (4), and when the state of the solution cavity tends to be stable, groove construction operation meeting the conditions is completed.
5. The method for drilling and water-soluble exploitation of deep novel polyhalite potassium salt mine according to claim 4, wherein the criterion of the stable state of the solution cavity is as follows: The volume increase rate of the whole solution cavity is less than 5%/d; The dumbbell-shaped solution cavity shape tends to be stable; The roof span rate of change is <2%/d; the fluctuation range of the potassium ion concentration is less than 10%; The density of the flowback brine is stabilized within the range of 1.20-1.25 g/cm 3 ; and (3) meeting all the conditions in the above criteria, namely finishing the groove building operation meeting the conditions.
6. The method for drilling and water-soluble exploitation of deep new polyhalite potassium salt mine according to claim 3, wherein the trench-construction operation adopts a double-well parallel operation mode.
7. The method for drilling and water-soluble exploitation of deep novel polyhalite potassium salt ores according to claim 1, wherein in the fourth step, fresh water with the mineralization degree of less than 500mg/L is injected into a solution cavity through a first vertical shaft (1), the fresh water injection amount is 30-40 m 3 /h, after the injection is carried out for a preset time T1, the solution cavity is filled to 50-80% of the whole solution cavity volume, water injection is stopped, and potassium-containing brine is pumped out from a second vertical shaft (2) after a reaction time T2.
8. The drilling water-soluble exploitation method of the deep novel polyhalite potassium salt ore is characterized by setting normal parameter ranges, namely potassium ion concentration k 1 —k 2 , k 1 =270~280g/L,k 2 =300-310 g/L, salinity p 1 —p 2 , p 1 =30~35%,p 2 =40-45%, density p 1 —ρ 2 , p 1 =1.10~1.20g/cm 3 ,ρ 2 =1.15~1.25g/cm 3 , temperature t 1 —t 2 , and t 1 =80~85℃,t 2 =90-95 ℃; when any parameter of the monitored potassium ion concentration, salinity, density and temperature exceeds the normal parameter range continuously for 2 hours or reaches an early warning value instantaneously, the ground data processing platform carries out early warning; Preferably, the early warning value is that the potassium ion concentration is less than 250g/L or more than 330g/L, the salinity is less than 25% or more than 55%, the density is less than 1g/cm 3 or more than 1.4g/cm 3 , and the temperature is more than 95 ℃ or less than 75 ℃.
9. A drilling water-soluble exploitation system of deep novel polyhalite potassium salt mine, which is characterized by being applied to the drilling water-soluble exploitation method of the deep novel polyhalite potassium salt mine according to any one of claims 1-8; the drilling water-soluble exploitation system comprises a first vertical shaft (1), a second vertical shaft (2), a horizontal butt joint well (3), a portable lithium potassium analyzer (4), a sonar detector (5) and a ground data processing platform.
10. The drilling water-soluble exploitation system of the deep novel polyhalite potassium salt mine according to claim 9 is characterized in that a first inner pipe I (1.1) and a first inner pipe II (1.2) are arranged in a shaft I (1), a second inner pipe I (2.1) and a second inner pipe II (2.2) are arranged in a shaft II (2), two inner pipes of each shaft are respectively an injection channel and a production channel, and water injection and drainage functions of the two inner pipes of each shaft are switched through a hydraulic control valve.

Description

Drilling water-soluble exploitation method and system for deep novel polyhalite potassium salt mine Technical Field The invention belongs to the technical field of deep sylvite mining, and particularly relates to a drilling water-soluble mining method and system for deep novel polyhalite sylvite. Background Polyhalite (chemical formula K 2SO4·MgSO4·2CaSO4·2H2 O) is used as a poorly soluble potassium salt mineral, the theoretical potassium oxide content can reach 28%, and the method has wide development and application prospects. The large-scale polyhalite layer is found in the early-middle triad stratum of the Sichuan basin, and the K 2 O distant resource quantity exceeds one hundred billion tons. However, most of them are often co-associated or inter-layered with anhydrite to form "gypsum-type polyhalite", which is hard in texture and poorly soluble in water. Aiming at the indissolvable ores, the prior development technology is mainly based on the premise of mining the ores to the ground surface, and then preparing potassium salt through the processes of crushing, calcining, water leaching, acidolysis or salt reaction and the like. The method usually needs to use chemical reagents such as strong acid, strong alkali and the like, and has high cost and environmental protection. Therefore, under the prior art conditions, the economic and effective development and utilization of insoluble polyhalite still face great difficulties. In recent years, the first world sea-phase-soluble novel polyhalite potassium salt ore found in Xuanhan areas in northeast China thoroughly changes the situation that the traditional polyhalite is difficult to use. The polyhalite in the ore deposit is in the form of chips and particles and is stored in a rock salt matrix, and the structure is loose and soluble in water, so that the polyhalite is named as 'novel polyhalite potassium salt ore', and the method has wide development and utilization prospects. However, the mineral deposit is currently ascertained that the burial depth of the mineral body is generally more than 3000 m, the occurrence condition is complex, and the mineral deposit is characterized by high temperature (the ground temperature is close to 100 ℃), high pressure, multilayer distribution, plastic deformation of salt rock and the like, and the mining difficulty is extremely high. For the exploitation of the soluble novel polyhalite, drilling water-soluble exploitation methods (such as China patent CN103321615A, CN102251759A, CN112253117A, CN105178963A and the like) are developed in the prior art, but the technologies are mainly designed for shallow sylvite ore deposits and are difficult to be suitable for deep exploitation. Especially in northeast areas of Sichuan, the depth of burial of ore body is big (more than 3000 m), the number of layers is many, the temperature is high, the salt rock plastic rheological property is strong, in deep water solution exploitation process, underground temperature is high, combines the extrusion of novel polyhalite sylvite ore, the mineralization process of deformation, and the plastic deformation of underground rock is strong, and formation pressure is big, dissolves and adopts back stratum to the corrosion cavity shape reaction sensitivity, leads to the cavity after the corrosion to take place easily showing deformation after the water injection. If the monitoring and control of the corrosion cavity are lacking, stratum collapse is easy to occur, and mining safety and efficiency are seriously affected. However, the existing drilling water-soluble exploitation technology shows obvious technical limitations when dealing with deep novel polyhalite potash salt ores, and cannot meet the actual exploitation requirements of the deep novel polyhalite potash salt ores. For example, the in-situ leaching method proposed in the patent with publication number CN103321615A is used for carrying out in-situ leaching on polyhalite deposit by preparing reaction liquid, but the method lacks effective monitoring on formation and evolution of underground solution cavities with burial depth exceeding 3000m, is difficult to cope with solution cavity instability caused by strong plastic rheological property of salt rock under high temperature and high pressure conditions, and new ions introduced into the prepared solution are easy to cause groundwater pollution and increase the difficulty of later potassium extraction. The method for collecting the polyhalite in the patent with the publication number of CN102251759A comprises the steps of determining a collecting well in a mining area, sequentially increasing well depths according to depths on a connecting line of the collecting well, digging a plurality of well lines to form a well pattern, wherein the well pattern is too high in drilling cost, low in utilization rate of the actual collecting well, and also lack of monitoring on underground cavity dissolving conditions, carrying out solution collec