RU2236578C1 - Method for underground dissolution of salt deposits - Google Patents

Abstract

FIELD: mining industry.

SUBSTANCE: method includes drilling of vertical well in massive of extracted chamber, casing of well, equipping it with concentrically placed water-feeding, brine-hoisting and operational pipes, feeding of dissolvent along brine-hoisting pipe, feeding of non-dissolvent along inter-pipe space between water-feeding pipe and operational pipe, forming of preparatory mine, extraction of brine along inter-pipe space between water-feeding pipe and brine-hoisting pipe. Dissolvent is injected with inert relatively to enveloping slats mass increaser for receiving heavy suspension in mass relation of mass increaser to dissolvent from 0.15:1 to 0.24:1. As mass increaser granules of magnetite in glass casing are used.

EFFECT: higher speed of dissolvent saturation, faster washout of preparatory mine of dissolving chamber, lower energy costs due to lesser number of saturation cycles.

2 cl, 1 dwg

Description

The invention relates to the mining industry and can be used in the extraction of fossil salts by underground dissolution through boreholes.

A known method for the extraction of solutions of potassium salts in the underground leaching of salt deposits. The method includes drilling wells, supplying a solvent to a salt deposit, according to the invention, together with chromium salts in a solvent, polypeptides of molecular weight 2000-10000 are supplied in a ratio of 100: (4-7). The disadvantage of this method is the low rate of saturation of the solvent and, as a result, the low productivity of brine extraction. (A.s. 1041676, E 21 B 43/28, 09/15/1983, bull. No. 34).

A known method of underground dissolution of salt deposits, adopted as a prototype. A well is drilled and a preparatory horizontal cut is eroded in the area of its bottom hole. Then erode the vertical output by supplying solvent with in-depth water supply. Submit a non-solvent in the vertical output and support it at the roof of the latter. For erosion of the underground chamber, a solvent is supplied to the bottom of the vertical excavation. At the same time, a solution of sodium chloride with a concentration of 25.5-26% and a hydrogen pH of 6-7 is fed into the upper part of the vertical output. The brine flow rate is maintained within 0.2-0.5 of the brine flow rate. The brine, mixing with the upward flow, forms a mixing zone with a high concentration of brine. The disadvantage of this method is the low rate of saturation of the solvent and, as a result, the low productivity of brine extraction. (A.S. 1488446, Е 21 В 43 / 28.23.06.1989, bull. No. 23).

The technical result of the invention is to increase the productivity of brine extraction by increasing the rate of saturation of the solvent.

The technical result is achieved by the fact that in the method of underground dissolution of salt deposits, including drilling a vertical well into the array of the worked-out chamber, casing the well, equipping it with concentrically arranged water supply, brine lifting and production pipes, feeding through the brine lifting pipe under solvent pressure, feeding through the annulus between the water supply pipe and production pipe under pressure of a non-solvent, the creation of preparatory workings, the selection of brine along the annulus the space between the water supply pipe and the brine lifting pipe, according to the invention, a weighting agent inert with respect to the containing salts is introduced into the solvent to obtain a heavy suspension in a weight ratio of weighting agent to solvent from 0.15: 1 to 0.24: 1.

The method of underground dissolution of salt deposits is also characterized by the fact that magnetite granules in a glass shell are used as a weighting agent.

The application of the proposed method in comparison with the prototype can improve the productivity of brine extraction by increasing the rate of saturation of the solvent.

The method of underground dissolution of salt deposits is illustrated by the scheme, where:

1 - production pipe;

2 - pickling pipe;

3 - water supply pipe;

4 - non-solvent, for example diesel fuel;

5 - design contour of the dissolution chamber;

6 - salt deposit;

7 - preparatory horizontal cut.

The method of underground dissolution of salt deposits is carried out as follows: a vertical well is drilled through the overburden into a salt deposit 6, the well is cased, equipped with concentrically arranged pipes: production pipe 1, water supply pipe 3, brine pipe 2.

To wash the preparatory horizontal cut 7, the shoe of the pick-up pipe 2 is lowered to the lower design position (1-3 m from the bottom of the well), and the difference between the shoes of the supply pipe 3 and pick-up pipe 2 is in the range from 5 to 15 m (depending on the required geometric the dimensions of the preparatory horizontal cut). Then, a solvent (for example, water) with a weighting agent added on the surface is supplied under pressure through the brine lifting pipe 2. The brine is given by the gap between the brine-lifting 2 and the water supply 3 pipes.

After erosion of the preparatory horizontal cut, the water supply pipe 3 is raised so that the difference between the shoes of the water supply pipe 3 and the brine lifting pipe 2 is from 15 to 100 m (depending on the geometric dimensions of the chamber) for erosion of the vertical output. Then, the operation of feeding the solvent with the added weighting agent in a mass ratio of the weighting agent to the solvent from 0.15: 1 to 0.24: 1 is repeated.

After erosion of the vertical output, the chamber is worked out by in-depth water supply, the operation of feeding the solvent with the added weighting agent is repeated. The development of the stock of the camera is carried out until it reaches the design circuit 5.

When weighting agent is added to the solvent, the density of the solvent increases, a heavy suspension is obtained, the density of which is greater than the density of the solvent. When a suspension enters the chamber, suspended solids are concentrated in the lower part of the dissolution chamber due to gravitational forces. Lighter solvent accumulates at the top of the chamber. The active process of dissolution occurs from the bottom up, due to this, the process of dissolution and saturation of the solvent occurs more efficiently. When using magnetite granules in a glass shell as a weighting agent, the process of removing the weighting agent from the brine is greatly simplified due to the fact that the granules can be removed from the brine with a magnet. A glass shell is necessary to protect magnetite from an aggressive environment - brine.

Fluid is introduced into the dissolution chamber through wells, typically equipped with two hanging pipe columns. The cross section of the inner (146 mm) and outer (219 mm) columns, through which water is usually supplied, is very small (area 0.0144 m ² ) in comparison with the section of the chamber (area up to 7-15 thousand m ² ). Therefore, the velocities of the fluid when it enters the chamber are abruptly quenched and become insignificant in comparison with the velocities in the well pipes (at a water delivery capacity of 50 m ³ / h, the velocities in the pipes are close to 1 m / s). In an individual chamber with a diameter of 100 m at a well productivity of 50 m ³ / h at a velocity V of an upward flow of solvent of 2 × 10 ^-3 m / s, it takes about 7 days to renew the fluid in a layer 1 m high.

When magnetite granules are added to the solvent in a glass shell under the same conditions, it will take about 5 days to renew the liquid in a layer 1 m high.

The mass ratio of the weighting agent to the solvent is taken based on the data given in the table.

The use of this method of underground dissolution of salt deposits provides the following advantages:

- increasing the rate of saturation of the solvent;

- acceleration of erosion of the preparatory development of the dissolution chamber;

- reducing energy costs by reducing the number of saturation cycles.

Claims (2)

1. The method of underground dissolution of salt deposits, including drilling a vertical well in the array of the worked-out chamber, casing the well, equipping it with concentrically arranged water supply, brine lifting and production pipes, feeding through the brine lifting pipe under solvent pressure, feeding through the annulus between the water supply pipe and the production pipe under the pressure of the non-solvent, the creation of preparatory workings, the selection of brine along the annulus between the water supply pipe and solopodemnoy tube, characterized in that the inert solvent is introduced with respect to the accommodating salts of heavy weight material for suspension in a weight ratio of weighting agent and solvent from 0.15: 1 to 0.24: 1. 2. The method according to claim 1, characterized in that magnetite granules in a glass shell are used as a weighting agent.