RU2517728C1 - Hydraulic borehole mining of hard minerals - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention relates to mining and can be used for hydraulic borehole mining of minerals. Proposed method comprises opening of the deposit via central and peripheral wells, placing the equipment therein and opening of adjacent chambers in layers, from bottom to top, starting from peripheral chambers. Prior to opening of the next layer through the entire bed thickness, undercut chamber is formed nearby soil of formed chamber and, parallel with said layer, of artificial ceiling of hardening material with inclination to centre. Shrinkage of fallen rock and filling of opened space with hardening material, opening and backfilling of central chamber at development of every chamber. After making of said artificial ceiling, several hydraulic cuts are made over the height of temporary wells. After formation of undercut space, rocks are hydraulically fractured from lower hydraulic cuts to force fluid into fracture unless rock failure into undercut space. Caved rock is partially flooded by hydraulic fracture fluid and giants to wash out the rock. As rock disintegrates, pulp is fed to the surface. As magazine level drops below design mark, hydraulic fracturing is repeated from hydraulic cut closest to stripped area, shrinkage, wash-out and discharge of pulp. Then, said jobs are repeated unless stripped area reaches aforesaid artificial ceiling. Now, shrunk rock is completely washed put, pulp is discharged and stripped area is filled.

EFFECT: selective extraction, decreased losses of minerals and costs, lower environmental effects.

8 cl, 5 dwg

Description

The invention relates to mining and can be used in mining mineral deposits by the method of downhole hydraulic production. The application of this technical solution is appropriate for mining deposits represented by ore bodies of a stratum, lenticular, etc. forms, including deposits, in which the reservoir is identified by the content of the useful component. Such deposits include, for example, diamondiferous kimberlite pipes of the Arkhangelsk region.

A known method of downhole hydraulic mining of solid minerals, including opening the deposits with central and peripheral technological wells, installing equipment in them and practicing non-adjacent chambers in layers from the bottom up, starting with the peripheral ones, with the formation of a contour gap before the next layer for the entire thickness of the layer, is cut spaces with hydraulic erosion near the soil of the chamber being formed and an artificial ceiling parallel to it made of hardening material, with a slope from the periphery to the center, shops digging the collapsed rock mass and laying the mined-out space with hardening material, mining and laying the remaining peripheral chambers, and, last but not least, mining and laying the central chamber (see RF patent No. 21251601, class E21C 45/00, 1988).

This method allows the selective extraction of minerals, represented by individual nests, lenses, layers, etc. In particular, kimberlite pipes in which the distribution of diamonds is extremely uneven.

However, this method has a number of disadvantages. In the case when the hardness of the enclosing rocks is high enough, the hydraulic erosion of the massif will require significant energy and fluid consumption, and may generally be ineffective. In this case, significant losses of crystalline raw materials are not ruled out. This is due to the fact that part of the crystals may remain in undestroyed "oversized".

A device for downhole hydraulic mining of solid minerals, including movable relative to each other, the external and internal injection pipe string, a central pulp pipe string installed in the cavity of the internal pipe injection string, and an auxiliary pipe with a hydraulic monitor (see AS No. 1700249, C. E21C 45/00, 1989).

This device is the closest to the intended purpose, but it cannot carry out hydraulic fracturing of a rock mass, i.e. cannot implement the proposed method.

The problem to which the present invention is directed is to increase the efficiency of mining mineral deposits.

The technical result of the invention is to ensure the selectivity of production, reducing losses of minerals, reducing the cost of extraction and transportation, and reducing the harmful effects on the environment.

The technical result is achieved by the fact that in the method of downhole hydraulic production of solid minerals, which includes opening the deposits with central and peripheral technological wells, installing equipment in them and practicing non-adjacent chambers in layers from the bottom up, starting from the peripheral ones, with the formation of the next layer of a contour gap for the entire thickness of the layer, the undercutting space near the soil of the chamber formed and the artificial ceiling parallel to it from the hardening material, with an inclination from the periphery to the center, storing collapsed rock mass and laying the mined-out space with hardening material, working out and laying the central chamber, after working out each chamber, after creating an artificial ceiling, several hydraulic pipes are created by the height of the technological wells, after the formation of the cutting space, the rocks are fractured from the lower hydraulic pipe and pumped in the resulting fracture, the liquid until the rock mass collapses into the undercutting space, the collapsed rock mass is partially flooded due to the liquid hydraulic fracturing and from hydraulic monitors used to wash the rock mass, as the latter is disintegrated, pulp is dispensed to the surface when the store level is lower than the design level, hydraulic fracturing from the hydraulic pipe closest to the mined space, storing, erosion and pulp delivery is repeated, then the operations are repeated until the space reached reaches the artificial ceiling, after which a complete erosion of the stained rock mass is carried out, the pulp is dispensed and the worked out space.

In the process of drilling, areas containing a useful component are isolated and only cameras lying in these areas are practiced.

In some cases, after hydraulic fracturing, liquid is supplied to the massif to collapse under the pressure necessary to saturate the rock mass with it, and then collapse, increasing the pressure of the fluid.

In addition, erosion is carried out from two hydromonitors, one of which is located near the soil of the chamber, and the other above the level of the fluidized rock mass flooding.

It is advisable to form a breakdown and an undercutting space with hydraulic fracturing and further hydraulic monitoring erosion from production wells located nearby.

To increase the stability of the walls of the worked out area, the liquid in the store is maintained no higher than the bottom level of the contour wells.

Surfactants are added to the liquid to improve rock disintegration.

With a significant area of the worked out area between the peripheral and central technological wells, intermediate technological wells are drilled, the chambers from these wells are drilled in the same way as the chambers from peripheral wells.

To achieve a technical result, a device for downhole hydraulic mining of solid minerals, including external and internal discharge pipe columns movable relative to each other, a central pulp discharge pipe string installed in the cavity of the internal pipe injection string, and an auxiliary pipe with a hydraulic monitor, is equipped with an additional hydraulic monitor mounted on the internal the discharge pipe string, and a fracturing nozzle located on the external discharge pipe string, while the washing pipe is installed with the possibility of fixed movement relative to the internal discharge pipe string, and the hydraulic fracture nozzle in the initial position closes the additional hydraulic monitor and is made in the form of a housing with a cavity and windows around which hydraulic chambers are installed, the outer walls of which are made elastic, the housing cavity is in communication with the hydraulic cavity chambers by channels, and in hydraulic chambers, spring-loaded pistons are installed, the rods of which are connected with the shutter flaps.

The indicated population includes all essential features necessary and sufficient to achieve a technical result.

The invention is illustrated by drawings, where:

figure 1 shows a General view of the worked out section in section;

figure 2 - mining chamber from a peripheral well;

figure 3 - a device for downhole hydraulic mining of solid minerals;

figure 4 - fracturing nozzle in the initial position.

Field development is as follows. An autopsy of section 1 of the central 2, peripheral 3 and, with a large width of the worked out section, intermediate 4 technological wells is performed. On the contour of the plot, contoured contiguous wells are drilled 5.

As a rule, these wells are drilled with a reduced diameter compared to the technological ones.

Prepare the bottom layer for mining. For this, a contour slit 6 is created to the layer height by any known method, a receiving chamber 7 in the central 2 well, an inclined artificial ceiling made of hardening material 8, and, parallel to it, an undercutting space 9.

The receiving chamber is created by a hydraulic monitor 10 of a device for downhole hydraulic mining of solid minerals 11, which is lowered on a pipe string 12 to a central well 2. Then, on a pipe string 13, a downhole hydraulic production of solid minerals 14 is also lowered into a peripheral well 3.

Due to the joint work of the devices for downhole hydraulic production 11 and 14, the formation of fissures of the slit to create an artificial ceiling 8 and undercutting space 9.

Testing begins with peripheral cameras.

After creating an artificial ceiling 8 in the chamber 15, several hydraulic pipes 16 are created along the height of the technological well 3 16. After the formation of the undercut space 9, hydraulic fracturing is performed from the lower cut and the fluid is injected into the resulting fracture fracture until the rock mass of mass 23 collapses into the undercut space 9. Collapsed rock mass they store and partially floode due to hydraulic fracturing fluid.

After that they turn on water monitors and wash out, as well as partial flooding of the stagnant rock mass (hereinafter referred to as store 17).

Under the action of an additional hydraulic monitor 18, a device for downhole hydraulic mining of solid minerals 14, a preliminary erosion of the magazine 17 above the liquid level 19 and recharge of the waterflood of the magazine occurs. Under the action of water filling the part of the store 17, pieces of rock become soaked, and the hydraulic monitor 20 of the device for downhole hydraulic mining of solid minerals 14, operating in the conditions of flooded bottom, finally transfers them to a pulp-like state and, when directed to the side of failure with the central well 2, pulp release. As the disintegration of the rock mass produce pulp to the surface. When lowering the level of the store 17 below the design level, the hydraulic fracturing operations from the log house 16, closest to the worked-out space 22, are stored, scoured, washed out and pulp delivered. These operations are repeated until the worked-out space 22 reaches the artificial ceiling 8.

After that make a complete washout of the store 17 and the issuance of pulp to the surface. Then lay the mined-out space 22 of the chamber 15 and proceed to the development of the next non-adjacent peripheral chamber. Then, if intermediate technological wells 4 were drilled, chambers from them are similarly worked out. Lastly, the central chamber is worked out from the central well 2 by a device for downhole hydraulic mining of solid minerals 11.

As you practice, each camera is laid with a hardening tab. It is possible to simultaneously test several non-adjacent chambers from the same type of technological wells. For example, chambers from peripheral wells 3 and 24 can be tested simultaneously.

To improve the disintegration of the rock mass into the massif to be collapsed, after the formation of a hydraulic fracture, fluid is supplied through it under the pressure necessary to saturate the rock mass, but not sufficient for collapse. This operation can be performed simultaneously with storing, washing out and partial pulp delivery, obtained after the collapse of the previous array.

After working out the layer, they go on to working out the overlying one.

If the mineral is represented by nests, lenses, interlayers, etc., then during the drilling process, areas containing a useful component, for example containing diamonds, are isolated and layers and / or chambers lying only in these areas are worked out.

To facilitate the formation of a pit space 9 and to create an artificial ceiling 8 sequentially between the central 2 and intermediate, intermediate and peripheral 3, 24, etc. failures pass. Failures can be created both due to only hydraulic erosion from the indicated adjacent wells, and in two stages - the first stage of hydraulic fracturing, the second - hydromonitor erosion from wells, between which the failure occurs. The second technology is more appropriate, because after hydraulic fracturing, the resulting pulp will produce pulp obtained during the operation of the hydraulic monitor in the intermediate and / or peripheral production well 3.

To ensure the disintegration of the collapsed rock mass and to preserve the walls of the site from collapse, it is advisable to maintain the liquid in the store no higher than the bottom of the contour wells.

To intensify the process of disintegration, surfactants are used that are added to the liquid.

A device for downhole hydraulic mining of solid minerals includes external 25 and internal 26 movable relative to each other, with an additional hydraulic monitor 27, injection pipe columns, a central pulp delivery pipe pipe 28 installed in the cavity of the internal pipe injection pipe 26, and an auxiliary pipe 29 with a hydraulic monitor 30. The auxiliary pipe 29 is installed with the possibility of a fixed movement relative to the internal discharge pipe string 26 and has a cavity in common with it.

The central pulp delivery pipe string 28 can also be movable relative to the internal pipe delivery string 26. At the end of the external pipe delivery string 25, a hydraulic fracture nozzle 31 is placed in its initial position, which covers the hydraulic monitor 30. The hydraulic fracture nozzle 31 is made in the form of a housing with a cavity 32. Windows 33 are made in the housing around which the hydraulic chambers 34 with elastic outer walls 35 are installed. The cavity 32 of the housing is in communication with the cavity of the hydraulic chambers 34 with channels 36, and in the cavities of the hydraulic chambers p pistons 38, spring-loaded by springs 37, whose rods 39 are connected to the shutter flaps 40, are placed.

The device operates as follows. On the surface, before the device is immersed in the well, the auxiliary pipe 29 is moved relative to the internal injection column 26 and fixed in a position in which the hydraulic monitor 30 is at a predetermined distance from the additional hydraulic monitor 27 and oriented relative to it. The distance between the hydromonitors is selected from the operating condition of the hydromonitor 30 near the soil of the chamber, and the additional hydromonitor 27 is above the level of the fluid store 17 of the liquid 19. Then pipe pipes are lowered into the well, while the fracturing nozzle 31 overlaps the additional hydromonitor 27.

When the fluid is supplied to the inner column of the discharge pipes 26, it enters the hydraulic monitor 30 and erodes the surrounding rocks. Since the additional hydraulic monitor 27 is blocked by the hydraulic fracturing nozzle 31, water does not flow out of it and the additional hydraulic monitor 27 does not work.

In this mode, the device works when creating failures of the undercut space, the cavity for creating an artificial ceiling 8 and cuts 16, i.e. initial cavities. The creation of these cavities can be carried out in several stages, for which the device is moved along the height of the well. Moving can be carried out both from bottom to top, and from top to bottom, which is more appropriate, because after creating a slit space, the hydraulic monitor 30 remains at the soil of the chamber for use in its development.

After creating a slit space, the hydraulic fracture nozzle 31 located on the external pipe injection string 25 is installed against the first from the bottom of the cut. Then, liquid is supplied to the hydraulic fracturing nozzle 31 through an external injection pipe string 25. The fluid enters the cavity of the housing 32, from it through the channels 36, the fluid enters the hydraulic chambers 34, stretches their elastic outer walls 35 and presses them against the walls of the well, isolating its part between the chambers.

The springs 37 are designed so that the pistons 38 begin to move after isolating part of the well and increasing the pressure in the hydraulic chambers 34. When moving, the pistons 38 carry the stems 39 along, which in turn move the shutters 41 and 42 of the shutters 40 and open the windows 33. The fluid from the cavity of the housing 32 enters the window 33, then into the isolated part of the well and cut. The fluid can be supplied both in the hydraulic fracturing mode (in this case, a crack 43 develops from the cut 23) and in the water saturation mode of the massif.

When opening the windows 33, the pressure in the hydraulic chambers 34 may drop somewhat, but the springs 27 will return the rods 39 to some distance and partially block the windows 36, the fluid supply to the isolated part of the well will decrease, and the pressure in the hydraulic chambers 34 will increase. Thus, the pressure ratios in the hydraulic chambers 34 and the isolated part of the well are self-regulated, and under any conditions, part of the well will be reliably insulated by pressing the elastic outer walls 35 of the hydraulic chambers 34 against the walls of the well.

After the collapse of the array 23, the inner column of the discharge pipes 26 is moved until the nozzle of the additional hydraulic monitor 27 is released from the hydraulic fracture nozzle 31. The liquid begins to flow into both hydraulic monitors 30 and 27, washing the magazine 17, the first under the conditions of flooded bottom, the second drained.

Fracturing nozzle 31 can be used only as a packer. For example, when creating a hydraulic fracture by injecting water through a hydraulic monitor 30 into the cut (the cut may be inclined) when creating a slit space, the bottomhole part of the well is isolated by supplying fluid to the hydraulic fracture nozzle 31 under pressure, which compresses the elastic outer walls 35 of the hydraulic chambers 34 to the walls of the well and insufficient for hydraulic fracturing from windows 33.

The application of this technical solution will significantly reduce development costs. Moreover, due to the fact that the method provides selective excavation of individual nests and interlayers and leaving the host nests of rocks in the array without destruction, which were also destroyed and delivered to the surface using known technologies, it becomes profitable to develop deposits with a low but compact concentration of useful component. Such deposits include many diamondiferous kimberlite pipes of the Arkhangelsk region, in which nests with a high diamond content are located in the mass of “empty” kimberlite.

In addition, the harmful effect on the environment will be significantly reduced, since the selective method requires significantly less water consumption, a significant amount of rock will not rise to the surface, which entails a reduction in the area of sedimentation tanks and tailings.

Claims (8)

1. A method of downhole hydraulic mining of solid minerals, including opening a deposit with central and peripheral technological wells, installing equipment in them and practicing non-adjacent chambers in layers from the bottom up, starting from the peripheral ones, with the formation of a next layer of a contour gap for the entire thickness of the layer, undercutting space near the soil of the chamber formed and an artificial ceiling parallel to it made of hardening material, with an inclination from the periphery to the center, storing collapsed mining masses and laying of the worked-out space with hardening material, working out and laying of the central chamber, when each chamber is worked out, after creating an artificial ceiling, several hydraulic pipes are created by the height of the technological wells, after formation of a cutting space, hydraulic fracturing is performed from the lower hydraulic pipe and the liquid is pumped into the resulting crack until collapse rock mass into the undercutting space, the collapsed rock mass is partially flooded due to hydraulic fracturing fluid and from hydraulic monitors, which erosion of the rock mass, as the latter is disintegrated, the pulp is dispensed to the surface, when the store level drops below the design level, the hydraulic fracturing operations from the hydraulic pipe are repeated, the closure, erosion and pulp delivery are repeated, then the operations are repeated until the artificial ceiling reaches the artificial ceiling and then produce a complete erosion of the stained rock mass, the issuance of pulp and the laying of the worked out space. 2. The method of downhole hydraulic mining of solid minerals according to claim 1, in the process of drilling, sections containing a useful component are isolated and only cameras lying in these sections are worked out. 3. The method of downhole hydraulic mining of solid minerals 1 and 2, after hydraulic fracturing, the liquid to be caved in is fed to the array under the pressure necessary to saturate the rock mass, after which caving occurs, increasing the pressure of the liquid. 4. The method of downhole hydraulic mining of solid minerals according to claim 1, the erosion is carried out from two hydraulic monitors, one of which is located near the soil of the chamber, and the other above the level of the flooded mineralized rock mass. 5. The method of borehole hydraulic mining of solid minerals according to claim 1, the breakdown and undercutting space is formed by hydraulic fracturing and further hydraulic monitoring erosion from adjacent production wells. 6. The method of downhole hydraulic mining of solid minerals according to claim 1, the liquid in the store is maintained no higher than the bottom level of the contour wells. 7. The method of downhole hydraulic mining of solid minerals according to claim 1, surfactants are added to the liquid. 8. The method of borehole hydraulic mining of solid minerals according to claim 1, intermediate technological wells are drilled between peripheral and central technological wells, chambers from these wells are mined in the same way as chambers from peripheral wells.

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