SU1610049A1 - Method of methane drainage from coal seam - Google Patents

Abstract

The invention relates to the mining industry. The goal is to increase the efficiency of degassing by intensifying the process of extracting the working fluid from the reservoir. The well is drilled, lined with pipes, the tubing string is separated, the casing and the cementing ring are perforated, the working fluid is injected into the formation in hydraulic fracturing mode and maintained in the formation. Air is injected into the reservoir cyclically through a column with a closed annulus. In each cycle, after supplying air in a volume that is 15–25 times the volume of the fluid in the formation, the annulus is opened, and the injected air is released. Air-lift pumping of the working fluid after each cycle is carried out annularly until it stops its exit from the well. Gas extraction begins after removal of the working fluid from the formation. The advantage of the invention is to achieve a more complete degassing by intensifying the process of extracting the working fluid from the formation through the use of the piston effect of air. 2 Il.

Description

The invention relates to the mining industry and can be used for the degassing of coal seams.

I ...

The invention is to increase the efficiency of degassing by intensifying the process of extracting the working fluid from the reservoir.

FIG. 1 shows a graph of the height of the water column in the well from the time counted from the moment of release of air; Fig. 2 is a diagram explaining the implementation of the method.

The graph shows the approximate numerical values of the increase in the height of the column and the time of stabilization of the level of the working fluid in the well, H p - the water level in the well before the injection of air into the formation. A temporary: increase in the level of water makes it possible to effectively use at this moment methods for removing water from either the surface: air pumping and others.

.The graph shows the values of these

values typical of a hydraulic junction; : D

316

Research Institute of formations with a power of 3–8 m with a working fluid volume of 1000–3000 m and subsequent air injection with a volume of 10–60 thousand nm. Under actual conditions, the bleeding of such volumes of air from the well takes at least 1 hour and therefore an air-lift pumping is necessary to start immediately immediately after the bleeding.

The rise of the working fluid column after injection and air bleeding is explained by the ejector effect, i.e. the air exhausted from the well creates a vacuum zone into which water from the reservoir flows. The water is then picked up by the air flow and transported up the well. Taking into account all the forces acting on the water being raised, namely, the force of gravity, the force of friction against the surface, the buoyancy force acting on the air directly in the reservoir, shows that the volume of air pumped into the formation is long to 15-25 times the volume of working fluid that must be transported from the reservoir to the surface.

The complex effect on the reservoir, B1 stimulating pneumatic depreciation of the working fluid, followed by air-lift pumping, is carried out 1-fold in order to reuse the effect of water inflow into the well after extraction and air release.

The method of degassing a coal seam is carried out as follows (see FIG. 2).

A borehole is drilled, it is lined with pipes 1, a column of pump-compressor pipes 2 is lowered into it, the casing and plugging rings are perforated to form perforations 3 and perforations 4 in the coal seam 5, and the working fluid is injected hydrodislocation with, exceeding p51M natural injectivity of the formation. After the cracks 6 and openings of the working fluid in the reservoir have been opened, they are pneumatically exhausted by injecting air into the reservoir with a pumping volume exceeding 15 to 25 times the volume of the working fluid in the reservoir. After that, the well is opened to inject air from the well and the reservoir, and the airlift pumping of the working fluid from the well begins by injecting air at the level of 049.

The tubing tubing and air and water discharge through the nub 7. After that, as the water flow from the well ceased, air was again forced into the reservoir and the whole cycle of well development work was repeated until the water flow ceased, and then gas was removed from tolchi.

0 Example. After completion of the work on the equipment for the hydraulic dissection wells, the installation of the column of pump-compressor spring pipes, perforation and the formation of the near-well zone is carried out

5 reservoir hydraulic dissection.

The injection pressure of the working fluid into the reservoir in the hydrodissection mode, the volume and rate of injection are determined by the known method. With a depth of 600 m, a reservoir thickness of 8 m, an effective porosity of 3.5%, the radius of the proposed impact zone is 200 m, the pressure of the injected fluid is 12.0-15.0 MPa, the discharge rate is 60-90 l / s, working fluid injection 2000 m. Liquid injection is performed by pumping units 4AN-700. After the cracks detected by the pressure drop of the working fluid injection and the total water volume is pumped up, the well is closed and maintained for 2-4 months. for uniform impregnation of the formation and completion of the process of water methane in the sorption

volume of coal Then, the injection of air through the tubing with the closed annulus — the space between the casing and the column

0 tubing volume of 40 thousand m. After that, the well is opened, the injected air is vented, and the airlift pumping of water begins, i.e. air is pumped through the tubing string with the open pipe, through which air and water are thrown to the surface. Within 14 days, 1000 m of water was extracted from the reservoir, after which the discharge of water stopped. The borehole Q is closed and air is again injected into the formation with a volume of 20 thousand m (since there is 1000 m left in the formation, the volume of air is correspondingly reduced). After that, the well is opened and 800 m of water is extracted by airlift pumping. In the third cycle, 4000 m of air is injected into the formation, the remaining water is removed by airlift pumping, and work is started to extract gas from the bulk. For 6 months, gas is extracted during its expiration, and then a vacuum pumping station is connected to the well and gas is extracted for two years before working out of the well by means of mining operations. The proposed method allows for a more complete degassing of the coal seam due to the quality development of the well and the reservoir. working fluid of the hydraulic dissection and thereby increase the phase permeability of the array for the gas leaving the reservoir, which ultimately leads to an increase in the efficiency of degassing of coal reservoir and mining safety in the zone of influence of the well.

The objects of application of the proposed method can be high-gas-bearing mine floors.

Claims (1)

Invention T is a coal seam degassing tool that includes the drilling of wells with over five ten injecting into the reservoir the working fluid in the hydrodissection mode, holding it in the reservoir and pushing filter pores and cracks out by pumping air into the reservoir and then extracting gas from the formation, which is characterized by the fact that in order to increase the degassing efficiency by intensifying the process removing the working fluid from the reservoir, the injection of air into the reservoir is carried out cyclically through a column with a closed annulus, and in each cycle, J5 can barely deliver air in a volume 15-25 times greater than the volume of the working fluid in the reservoir bone za- otkrshayut pipe, the injected air is vented and making t airlift pumping of the working fluid until no blew her exit from the borehole, wherein the gas extraction is carried out after removing the working fluid from the formation. 20 23 of FIG. one five t, v Editor E. Kopcha Compiled by I. Fed eva Tehred L. Oliynyk Proofreader O. Kravtsova Order 3718 Circulation 370 V1SHIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. D. 4/5 Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 FIG. 2 Subscription