EA013446B1 - Method of phosphorite deposit seam development - Google Patents

Abstract

This invention relates to the mining and may be used in the process of phosphorite deposit development, including phosphorites of nodular type and seams of low thickness. An objective of the proposed invention is to increase the effectiveness of phosphorite deposit seam development with the method of leaching. The assigned objective is reached with the fact, that in the method, comprising phosphorite deposit seam exposing with at least two (injection and production) wells, casing them with corrosion-resistant pipe columns, equipping of well bottom part with filters, equipping of well collar with X-mas tree and pumping and compression pipes, well linkage, choice of acid type and concentration, providing the highest selectivity of commercial component extraction, injection of selected solvent to injection well, pump-down of obtained solution from production well, the production well is equipped additionally with wave radiator and packer, the well linkage is carried-out with the help of coiled-tubing installation and flexible seamless pipe, the selected solvent is feed to the productive seam in pumping and compression pipes with simultaneous overlaying of elastic waves, for which it serves as waveguide, the elastic waves are oriented in the required direction by wave reflector and packer, in such manner calculated permeability is pointed on the deposit inter-well area. The use of proposed method will allow increasing the effectiveness of phosphorite deposit development with the method of leaching at the expense of formation of additional permeability of productive seam. In the case of «geochemical barriers» formation this method allows to destroy them and simultaneously to reduce the viscosity of working solutions, to intensify the solution process of nodular phosphorites. The proposed method allows fighting against working solution leakages and water inflows by means of colmatation screens creation with the use of shock-wave intensity and coil tubing, and well linkage by means of flexible pipe and directed wave action makes the process controlled.

Description

The invention relates to mining and can be used in the development of phosphate deposits, including jelly type and formations of low power.

There is a method of phosphate mining, based on the use of borehole hydrotechnology, in which the phosphate rock is opened by means of wells, hydrodynamic equipment is installed in the well, produce hydraulic destruction of the rocks of the reservoir, and the destroyed rocks are delivered in the form of a slurry to the surface of the earth [1].

The disadvantage of this method is its low efficiency, especially in the development of low-thickness formations, as well as the impossibility of its use in the presence of weak rocks in the overlying phosphate reservoir.

A method is known in-situ leaching of phosphates comprising autopsy reservoir injection and production wells, their cased corrosion resistant columns, pipes, equipment downhole portion wells filters sboyka mining and stored pressure wells by fracturing, the choice of type and concentration of the leaching solutions (acid), injecting through a stored pressure wells leach solutions and pumping (extraction) through mining wells of solutions with minerals [prototype 2].

The disadvantage of this method is its low efficiency due to the following conditions: first, the use of concentrated acids to decompose raw phosphate leads to a sharp deterioration in filtration of leach solutions due to clogging of the pores of the reservoir with carbon dioxide and decomposition of carbonates (if present in the reservoir), redeposition salts in front of the leaching front (formation of the so-called "geochemical barriers") and increase the viscosity of the solution;

secondly, this method is not applicable with low permeability of productive formations;

thirdly, the effectiveness of this method is sharply reduced due to the cost of combating water inflows with significant water content of the productive reservoir or due to leakage of working solutions (if there are absorbing layers in the section);

fourth, the hydraulic fracture used in this method for pumping injection and production wells is uncontrolled, in which cracks in the reservoir can be formed in the most undesirable directions.

The task of the invention is to increase the efficiency of development of layers of phosphate rock deposits by leaching.

The task is achieved by the fact that in the method of development of reservoirs of phosphate deposits, including the opening of the phosphate reservoir by at least two (injection and production) wells, their casing with corrosion-resistant pipes, equipment of the bottom hole of the wells with filters, and the mouth of the wellhead, equipment of the wells and compressor wells pipe assembly, well coupling, selection of the type and concentration of the working fluid, ensuring the highest selectivity of extraction of the useful component, injection of the selected working fluid and in the reservoir through the injection well, pumping the resulting solution through the production well, the injection well is additionally equipped with a wave emitter, a wave reflector and a packer, the wells are squeezed using a coiled tubing installation and a flexible seamless pipe, the working fluid is fed through the tubing to the reservoir the simultaneous imposition of elastic waves, for which the working fluid serves as a waveguide, the elastic waves orient the wave reflector and packer mainly in the direction of production wells and thus induce additional permeability at the interwell interval of the reservoir.

The proposed method is as follows.

The reservoir of phosphate rock is opened by at least two (injection and production) wells, surrounded by corrosion-resistant pipe columns, the bottom-hole part of the wells is equipped with filters, and the wellhead is equipped with flowing fittings. In addition, the wells are equipped with tubing. The injection well is additionally equipped with a wave emitter, a wave reflector and a packer, select the type and concentration of the working fluid (for example, sulfuric, hydrochloric or other acid), providing the highest rate and selectivity of leaching of the useful component. The wells are collapsed using a coiled tubing unit and a flexible seamless pipe. Via tubing pipes, a working fluid is selected into the productive formation with simultaneous application of elastic waves, for which the working fluid serves as a waveguide. Elastic waves orient the wave reflector and packer mainly in the direction of the production well.

The impact of elastic waves induces additional permeability at the interwell well site, which is necessary for high-performance well operation, and at the same time destroys geochemical barriers, ensuring a constant renewal of the contact surface of the working fluid and mineral. This increases the rate of leaching and the extraction rate of the useful component. The solution obtained by the interaction of phosphorite and working fluid is taken from the production well for its processing. The work is carried out in such a way that the volume of injected working fluid by 3-5% is lower than the volume of the selected solution.

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Using the proposed method will improve the efficiency of the development of phosphate deposits by leaching due to the controlled coiled tubing sboki wells, the formation of additional permeability of the reservoir, reducing the viscosity of the solution and the destruction of geochemical barriers. In particular, the method allows to intensify the process of dissolution of chelivak phosphate.

With the leakage of working solutions and water inflows, the proposed method allows you to fight by creating clogging screens using the energy of shock waves and coiled tubing, and the bleeding of wells with a flexible pipe and directional wave action is made process controlled.

Information sources

1. Report on contract 4/99: “Develop technology and equipment for downhole hydraulic mining (SRP) of jellyfish phosphates as applied to the mining and geological conditions of the Lobkovichsky field in order to obtain raw materials for the production of phosphate fertilizers and feed phosphates”, the National Academy of Sciences of Belarus, Scientific Belgeo Research Geological Unitary Enterprise, Minsk, 2002, archive of Belgorkhimprom, archive number 789.

2. Arens V.ZH. Physico-chemical geotechnology. M .: Izd-vo MGGU, 2001, pp. 526-540 - prototype.

Claims (1)

CLAIM A method of developing formations of phosphorite deposits, including opening a phosphorite formation of at least one injection and one production well, casing them with corrosion-resistant pipe columns, equipping the bottom-hole part of the wells with filters, and wellheads with flowing fittings, equipping the wells with tubing, disabling the wells, selecting the type and the concentration of the working fluid, providing selectivity for the extraction of the useful component, the injection of the selected working fluid into the reservoir through the injection well, pumping the obtained solution through the production well, characterized in that the injection well is additionally equipped with a wave emitter, a wave reflector and a packer, the wells are disrupted with the help of a coiled tubing installation of a flexible-seamless pipe, the working fluid is fed into the reservoir by the simultaneous application of elastic waves, for which the working fluid serves as a waveguide, and the elastic waves are oriented by the wave reflector and packer mainly in the direction of the production well. 4 ^ 8) Eurasian Patent Organization, EAPO Russia, 109012, Moscow, Maly Cherkassky per., 2