SU1364702A1 - Method of leaching minerals from low-permeability formations - Google Patents

Abstract

The invention relates to geotechnology and provides effective leaching of a mineral from layers when high-permeable rocks are present in the roof between the layer and the aquitard while reducing the loss of mineral and non-production costs of the leach. sieve solution. The reservoir is opened by injection and pumping wells, in which the production casing is placed. Then, perforation of injection columns (NC) is carried out in the zone of highly permeable rocks at the level of the seam roof and perforation of the pumping columns (OK) in the same interval directly below the aquifer. A coagulating fluid, such as a soda solution, is supplied to the NC. It is retracted through the perforation QA, when the mudding reaches the maximum coverage ratio for the power of high-permeability rocks. Then, the perforations in NC and OK are blocked (collimated). The clogging is performed using, for example, a bituminous mixture pumped into the holes through a special column, and the perforation interval is isolated from the well by packers. The NCs are again perforated with the formation of a perforation interval under the reservoir, and the PCs are perforated directly above the reservoir. Then leach solution is injected into NK. Productive solution is pumped out of OK. 2 Il. (/

Description

The invention relates to geotechnology and can be used in the leaching of minerals from weakly permeable formations whose host rocks are characterized by increased permeability.

The purpose of the invention is to improve the leaching efficiency of a mineral from layers when high-permeable rocks are present in the roof between the layer and the aquacorum, while reducing the loss of mineral and unproductive leaching solution.

FIG. 1 and 2 are diagrams illustrating the sequence of operations of the method.

Example. Leaching of a mineral from a low-permeable reservoir 1 in the presence of 2 highly permeable rocks between the reservoir and the upper aquitard 2.

The reservoir 1 is opened by injecting 4 and 5 wells, while the casting wells 4 are re-drilling the reservoir 1 into the soil of the latter, 0-well wells 5 are drilled to the top of reservoir 1, then in wells 4 and 5. the production columns are placed, respectively, 6 and 7, and the annulus is plugged with a cement mortar. After that, perforation of 8. injection columns 6 in the range of highly permeable rocks 3 directly above formation 1 and perforation 9 of exhaust columns 7 in the same interval are performed directly below the aquitard 2. A clogging fluid, for example, a synthetic resin solution, soda solution, air and t, d, from its temporal drain through perforation of 9 pumping columns 1 until the colmatation reaches the maximum power coverage ratio of highly permeable rocks 3, Cross filtering of the clogging agent by poro Ze ie from injection wells 4 directly from reservoir 1 to pumping wells 5 directly below the aquitard 2, provides the maximum coverage of the entire reservoir of the high-permeable rocks 3 and the uniform distribution of this plug in the rocks 3, while left above the reservoir I of the pumped wells 5 there remains a zone 10, not covered by mudding. In this way.

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The proposed clogging technology provides the best conditions for subsequent leaching.

After clogging of highly permeable rocks 3, using known devices, perforations 8 and 9, previously formed in pumping 6 and pumping 7 columns, are clogged. Colmating perforation can be accomplished using a bituminous mixture injected into the perforation holes through a special column, and the perforation interval during the injection of the bituminous mixture is isolated from the well by packers located above and below the perforation interval.

Following this, the injection columns 6 are re-perforated with the formation of a perforation interval 11 under the reservoir 1. Perforation can be carried out using known means — hydrojet, bullet or cumulative perforators. The perforation interval 12 is also formed in the pumping column 7 directly above the reservoir 1 in zone 0 of highly permeable rock 3, which is not covered by clogging. Then the leaching solution is pumped into the pumping columns 6, and the productive solution is pumped out of the pumped columns 7, while the leaching solution is filtered through the reservoir, the solution is a useful component, and due to the fact that the rocks 3 are kolmatized, the solution that leaves the reservoir 1 moves into zone 10, which is the filter zone of the pump down column 7 ,. those. the entire productive solution is pumped out through the pumping well 5. All this allows for optimal filtration of the solution through the reservoir 1 and, accordingly, to reduce the loss of the useful component, as well as drastically reduce the non-productive leaching solution costs, since the permeable rocks 3 blocked by zones of clogging.

Claims (1)

Invention Formula The method of leaching of minerals from weakly permeable formations, including the drilling of injection and pumping wells, the placement of production columns in them, the supply of leach solution through injection wells under the formation with a branch productive solutions above the reservoir through pumping wells, characterized in that, in order to increase the leaching efficiency of the mineral from the reservoirs in the presence of highly permeable rocks between the roof of the reservoir and the overlying aquitard, prior to the beginning of the extrusion, perforating production columns in the zone of highly permeable rocks at the level of the roof of the reservoir, pump down perforation carried out directly under the aqueduct, the clogging fluid with its outlet through perforation of the pumping well columns is fed into the injection wells until it has fully worked out highly permeable rocks, then the previously formed drill holes of the injection wells and the pumping wells are blocked and the injection columns are perforated below the formation . eight. V j77, - and P L, -,. . -. L a c.  Et q. . 0 0 R . . la la, n a. .7 BUT J 8 f / vtf / 77