SU1716110A1 - Method of underground gasification of combustible minerals - Google Patents

Abstract

The invention relates to the underground gasification of coal and m. used in the development of coal, oil and shale. The purpose of the invention is to increase reliability and simplify the flow of blowing into the reservoir. The reservoir is opened by a well. The latter is equipped with a casing with an internal stand (BC) pipes. Through the sun into the reservoir serves oxygen-containing blast (D). Periodically move the point of entry D partial extraction of the sun and the reflow of the lower part of the casing. This reflow is effected by changing the direction of movement of the fire intake towards the injected D. To do this, reduce the flow rate D to 50-300 m / h while maintaining the oxygen concentration in it 40-95%. This feed mode is maintained for a time t l / Voa, where I is the partial extraction length of the aircraft, m; V03 the speed of movement of the fiery ambush towards the injected D. v oz 0.2-1 m / h. 2 Il. V / .. 5 y

Description

The invention relates to the underground gasification of coal and can be used in the development of not only coal seams, but also oil, shale.

There is a method of supplying blowing in a coal seam using a movable blowing pipe lowered into an inclined-horizontal1 or directional well. In this case, the well consists of two parts: cased and uncased. The mobile blowing of the water moves only along the length of the open hole part in the coal seam. As the coal seam evaporates, the moving blast pipe is periodically removed, which ensures the transfer of the feed point to the hot coal surface.

The disadvantage of this method is the possibility of pinching the movable blow pipe due to the occurrence of rock pressure in the open hole part.

There is also known a method for supplying blowing, in which the blow hole is cased to its full length, and the supply point is blown into coal and the formation is carried out by sequential installation of sealing plugs and a block of the said string in the well casing relative to each installed plug in the well casing string.

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The disadvantage of this method is the complexity of its practical implementation, which consists in the periodic alternation of operations for installing the plug, shooting through the columns and forcing the blow into the open coal seam.

The closest to the present invention is a method for supplying a blast into a coal seam, in which the internal stand of the pipes ends with a methane-oxygen burner and is removed as the casing well is burned to move the firing hole.

The disadvantage of this method is the complexity of its practical implementation and the unreliability of fixing the rhnevoy downhole along the well length, since, on the one hand, the performance of the burner at a great depth (the length of the internal stand of pipes reaches 1000 m and more) is very problematic, and, on the other hand, On the other hand, with the supply of oxygen blowing into the well, uncontrolled movement of the fireplate (source of combustion) and melting of the casing string in the coal seam in the direction opposite to the movement of the blow are possible.

The goal is achieved by the fact that according to the method of underground gasification of combustible minerals, including the opening of a producing well, its equipment with a casing string and an internal stand of pipes and the supply of oxygen-containing to blow into the formation through the internal set with periodic displacement of the point of entry to blow into the formation partial by extracting the internal stand and melting the casing, the reflow of the column is carried out by changing the direction of movement of the fire head towards the injected air by means of ohm reducing flow blowing to 50-300 m / h and use while blowing with an oxygen concentration of 40-95% of said delayed supply blowing mode within the time defined by the dependence of

t

ta1

where t is the dwell time of the feed blown in the casing reflow mode, h;

I is the length of the partial extraction of the internal rod, m;

Woz - the speed of movement of the fire in the direction towards the injected blast, 2-1, OM / 4.

The purpose of the invention is to increase reliability and simplify the flow of blowing into the reservoir.

The proposed method differs from the known one in that the blast into the well is supplied only through the internal becoming of pipes and

at the same time in two successive stages, in the first of which - in the amount of 50-300 m3 / h for a time equal to 1 / У0з h (I is the length of the extracted internal stand of the pipes, 2-1.0 is the speed of movement of the combustion center along casing length, m / h).

The blast through the inner tube, ending with a special nozzle, is flowed in the plane of the coal seam.

FIG. 1 shows a device for carrying out the proposed method; in fig. 2 - the optimal parameters of the first stage of the method.

A well for supplying a blast into the coal seam contains a casing 1, within which a movable pipe 2 is installed, ending with a guide nozzle 3.

The proposed method for supplying blowing into a coal seam is carried out as follows.

The blast is fed to the inner tube having become 2. In the first stage (shown in FIG.

1) a moderate amount is blown (Oa or Oa + no). The blast moves inside the well along the casing 1 down into the gassed space 4 of the underground gas generator. The hearth of the fire pit moves towards this blast, gradually melt the casing and form an expanded (instead of the original drill) channel 5. Thus, a new reaction surface is formed in the coal seam. As soon as the remaining part of the casing 6 is melted, the firing face will be fixed in the cross section of the guide nozzle 3, the transition to the second stage - coal gasification itself. In the second stage, the blast, preferably oxygen or air enriched with oxygen, in a mixture with superheated steam, is injected into the well in large quantities and carries out intensive extraction of the coal seam. After vygazovy coal seam on both sides of the well to about the state shown in Fig. 1 dotted position of the internal position

2 tubes, the latter is removed to the desired length and the first stage of the process is repeated. Part of the casing is melted and the source of combustion is moved up along it, forming a new reaction surface along the length of the borehole channel, etc.

It was established experimentally that the flow rate of the injected blowing in the first stage should be 50-300 m3 / h (pure oxygen). At the same time, the flow time of the first stage (d) is determined by the length (I) to which it is required to move the burning center towards the injected blast, and the speed 5 of moving the burning center (Vos), accompanied by the fusion of the casing of the well.

The results of experiments on the model are presented in FIG. 2. As the blow 10 use technical oxygen (95% 02).

At the oxygen consumption of 20 and 40 m / h, the metal column did not melt and the center of combustion did not move along the coal towards the blast. This is due to the fact that at this 15 flow rate the heat balance in the zone of the combustion center is such that the heat generated is not enough to heat the coal before the combustion center to the coal ignition temperature. The source of combustion does not move, the 20 column does not melt. At a consumption of oxygen of 50 m3 / h, the combustion center begins to move (, 2 m / h), since the heat released in its zone is not enough not only to melt the column that warms up the coal 25 in front of it to the ignition temperature. With an increase in oxygen consumption up to 300 m3 / h, the speed of movement of the source of combustion increases. However, with oxygen consumption of 310 and 320 m2 / h, the combustion center ceases to move, due to the excess heat carried away from the combustion center (in the direction of blowing) over the heat required for the column to be melted and the underlying coal to heat up. Thus, the movement of the combustion hearth 35 and the reflow of the column are observed in the range of oxygen consumption of 50-300 m3 / h.

On the air blast, it is not possible to melt down the column and to move the burning center 40 towards the blast. With an increase in the oxygen concentration in the blast of up to 40%, countercurrent movement of the source of combustion and reflow of the column begins.

By varying the oxygen concentration in the 45 blast from 40 to 95%, as well as its consumption, it is possible to flush the column (with countercurrent movement of the combustion chamber) and adjust the diameter of the worked up reaction channel. With a 50 increase in the oxygen concentration in the blast and a decrease in the flow rate of exchanger, a decrease in the diameter of the worked reaction / promotional channel was observed.

In the second stage of the process, blast is fed 55 to gasify with a directional (in the plane of the formation) flow, thereby achieving an intensive mass and heat exchange between it and the reaction surface of the coal seam. For such a method of underground gasification, a strict fixation of a fire slab, high efficiency and heat of combustion of the produced gas, as well as high completeness of coal bed gasification are typical.

The use of the proposed method of supplying blow to a coal seam in comparison with the known ones provides the following advantages:

the use of blowing for the supply in both stages of the internal rolling stock of the pipes ensures its reliability;

due to the strict fixation of the hearth of combustion (fire), high rates of underground gasification of coal are provided;

in comparison with the known, the proposed method is substantially simpler in practical implementation.

Claims (1)

The invention method of underground gasification of combustible minerals, including the opening of a producing formation by a well, its equipment with a casing and internal stand of pipes and the supply of oxygen-containing blow into the reservoir along the internal stand with periodic movement of the point of injection blow into the reservoir by partial extraction of the internal stand and melting of the casing, distinguishing In order to increase the reliability and simplify the flow of blowing into the reservoir, the reflow of the column is carried out by changing the direction of movement is injected toward the combustion slaughtering dutyu by reducing the flow rate and blowing 50-300 m / h and use while blowing with an oxygen concentration of 40-95% of said delayed supply blowing mode within the time defined by the dependence of I t where t is the dwell time of the feed blown in the casing reflow mode, h; I is the length of the partial extraction of the internal rod, m; V03 is the speed of movement of the fiery nab towards the injection blast, 2-1.0 m / h. V m / h I.O. 0.75 0.50 0.25 ZVG. m3