CN104047629B - The method that thin coal bed fully-mechanized mining gob side entry retaining directional drilling extraction closes on lower coal-bed gas - Google Patents

Abstract

A method for directional drilling and drainage of gas near the lower coal seam by directional drilling in gob-side entry retention in fully mechanized thin coal seams. Coal seam gas. The method of retaining roadways along the working face can alleviate the situation of large mining ratio and tense excavation replacement in the thin coal seam mining process, shorten the preparation time of the working face, and reduce the amount of driving in half-coal rock roadways. On the other hand, retaining roadways along the gob Drilling into directional boreholes, directional boreholes make the boreholes arranged in the lower coal seam in a large range, greatly increasing the area of coal seam gas extracted by boreholes, and reducing the gas content in the lower adjacent high-gas coal seam through the drainage of directional boreholes. Provide conditions for safe, high-yield and efficient mining of lower coal seams. This method solves the problems of difficulty in gas drainage in low-permeability and high-gas coal seams, large mining ratio in thin coal seam mining, high excavation rate, and tight excavation replacement.

Description

Directional Drilling Method for Drainage of Gas in Adjacent Lower Coal Seams in Gob-side Gob-side Retaining in Fully Mechanized Mining of Thin Coal Seams

technical field

The method for gas drainage by directional drilling in gob-side entry of the present invention is especially suitable for gas drainage in adjacent low-permeability coal seams after directional drilling in gob-side entry entry and pressure relief in the process of fully mechanized mining in thin coal seams.

Background technique

Thin coal seam pressure relief mining and directional gas drainage technology is an important subject of coal mining technology. Many experts and scholars at home and abroad have done a lot of research on this and obtained some research results. The reserves of thin coal seams in my country account for about 20.4% of the total coal reserves, but the current mining of thin coal seams has problems such as large mining ratio, high excavation rate, and tight mining replacement. For high-gas coal seams, the coal seam gas needs to be drained before mining to ensure that there are no potential safety hazards when mining high-gas coal seams. In the drainage roadway, drill holes are arranged in the drainage roadway to extract the gas in the high-gas coal seam. Since this method needs to arrange a separate rock roadway, there are problems such as high cost and complicated process.

Contents of the invention

Technical problem: The purpose of the present invention is to overcome the problems existing in the prior art, and provide a simple, effective, economical and reasonable thin coal seam fully mechanized mining method for directional drilling along gob-side entry and drainage of adjacent coal seam gas.

Technical solution: The method for extracting gas from adjacent coal seams by directional drilling in gob-side entry retention in fully mechanized thin coal seams of the present invention comprises the following steps:

a. In the mining process of thin coal seam working face, through the way of retaining roadway along the goaf, the transportation roadway of this coal seam working face is used as the return air roadway of the working face of the lower section;

b. As the thin coal seam working face continues to be mined under the synergy of the three processes of drum shearer coal cutting, scraper conveyor coal transportation, and hydraulic support roof support, the distance along the gob not less than 20m behind the thin coal seam working face Arrange a drilling field in the roadway, and set up the drilling rig, mud pump, drilling inclinometer and auxiliary equipment in the drilling field;

c. In the drilling field arranged in the gob-side entry retention, use the drilling rig to drill holes inclined to the bottom plate of the entryway, and ensure that the inclination angle of the drilling hole is less than 60°, and use clean water as the flushing medium during the drilling process;

d. When the inclined borehole is drilled to the roof of the lower coal seam, use the forced deflection device to build the deflection drill hole. When the deflection section of the drill hole is drilled to the lower adjacent coal seam and the trajectory changes to horizontal, continue horizontal drilling Drill the hole until the set length and complete the drilling of a hole;

e. After completing the drilling of a borehole, repeat steps c and d multiple times to drill multiple boreholes until completing a group of boreholes in the drill field;

f. Install gas drainage pipelines to drain the gas from the adjacent coal seams in a group of boreholes in the drilling site, and transport the extracted gas to the designated location through the gas pipelines laid in the transportation lanes of the working face;

g. With the continuous advancement of the thin coal seam working face, arrange a drilling site every 15-30m away from the first drilling site along the advancing direction of the thin coal seam working face, and repeat steps c, d, e, f to complete the gas pumping of all lower adjacent coal seams Pick.

Beneficial effects: according to the specific situation that the thin coal seam is close to the lower coal seam, the present invention uses the method of retaining the roadway along the gob during the mining process of the thin coal seam, and reserves the transportation roadway in the section as the return airway of the working face in the lower section. The drilling site is arranged in the gob-side entry of the working face, and the gas drainage boreholes are arranged in the drilling site for directional drilling to extract the gas in the adjacent lower coal seam after pressure relief, and directional drilling to extract the adjacent high-gas lower coal seam Gas in a free state after pressure relief. Through directional drilling, the boreholes are arranged in a large range in the lower coal seam, which greatly increases the gas extraction area of the coal seam. Gas drainage through directional drilling can reduce the gas content of the adjacent lower coal seam, which is more conducive to safe and efficient mining of the lower coal seam. On the one hand, the method of retaining entry along the gob can alleviate the problems of slow excavation of semi-coal and rock entry and tight replacement of the working face in the process of thin coal seam mining; It is necessary to arrange a special gas drainage roadway to complete the drainage work face, thereby avoiding the problems of long construction period and large investment. area. The purpose of "one lane with three uses" can be realized by retaining the roadway along the goaf. Before the roadway is retained, it is used as the transport level roadway of the mining face. After the roadway is retained, the drilling site is arranged in the roadway to drill directional drilling holes, and the mining of the mining face is completed. Afterwards, the gob-side retaining entry can be used as the return air level entry of the working face in the lower section. The method has low comprehensive investment and has wide practicability.

Description of drawings

Fig. 1 is the production of the mining face of the present invention and gob-side retaining and directional drilling plane layout;

Fig. 2 is a sectional view of the present invention perpendicular to the advancing direction of the working face.

In the figure: 1-transportation level roadway at the working face, 2-working face in the lower section, 3-gas pipeline, 4-hydraulic support, 5-roller shearer, 6-scraper conveyor, 7-gobside entry retention, 8-drilling field, 9-inclined drilling, 10-drilling rig, 11-down adjacent coal seam.

detailed description

An embodiment of the present invention will be further described below in conjunction with accompanying drawing:

According to the present invention, the method for extracting gas from adjacent coal seams by directional drilling in gobside entry retention in fully mechanized thin coal seams, the specific steps are as follows:

a. During the mining process of the thin coal seam working face, the transportation level entry 1 of the working face of the coal seam is used as the return air entry level of the working face 2 of the lower section by means of retaining the entry along the gob;

b. With the continuous mining of the thin coal seam working face under the synergy of the three processes of drum shearer 5 cutting coal, scraper conveyor 6 coal transportation, hydraulic support 4 supporting the roof, the distance from the thin coal seam working face is not less than 20m behind A drilling field 8 is arranged in the gob-side entry 7, and a directional drilling rig 10, mud pumps, drilling inclinometers and auxiliary equipment are arranged in the drilling field;

c. In the drilling field 8 arranged in the gob-side entry 7, use the drilling rig to drill holes 9 inclined to the bottom plate of the roadway, and ensure that the inclination angle of the drilling holes is less than 60°, and use clean water as the flushing medium during the drilling process;

d. When the inclined borehole 9 is drilled to the position of the lower adjacent coal seam roof, the forced deflection device is used to carry out the deflection drilling. When the drilling deflection section is drilled to the lower adjacent coal seam 11 and the inner trajectory changes to horizontal, continue horizontal drilling Drill into the hole until the set length and complete the drilling of a hole;

e. After completing the drilling of a borehole, repeat steps c and d multiple times to drill multiple boreholes until completing a group of boreholes in the drill field;

f. Install the gas drainage pipeline to drain the gas from the adjacent coal seam in a group of boreholes in the drilling site, and transport the extracted gas to the designated location through the gas pipeline 3 laid in the transportation lane 1 of the working face;

g. With the continuous advancement of the thin coal seam working face, arrange a drilling site every 15-30m away from the first drilling site along the advancing direction of the thin coal seam working face, and repeat steps c, d, e, f to complete all the gas in the next adjacent coal seam 11 sampling.

Claims (1)

1. the method that thin coal bed fully-mechanized mining gob side entry retaining directional drilling extraction closes on lower coal-bed gas, is characterized in that, comprises the steps:

A. in thin seam working surface recovery process, by the mode of gob side entry retaining, using this working face of coal seam haulage way (1) as lower curtate working face (2) tailgate;

B. along with the continuous exploitation of thin seam working surface under flitting (5) coal cutting, drag conveyor (6) fortune coal, three operation synergies of hydraulic support (4) supporting roof, in the gob side entry retaining (7) that is not less than 20m apart from thin seam working surface rear, arrange a drill site (8), and in drill site, lay directional drilling machine (10), slush pump, drillhole inclination survey instrument and auxiliary equipment;

C., in the drill site (8) of arranging in gob side entry retaining (7), utilize rig to roadway floor inclined drill (9), and ensure that dip angle of hole is less than 60 °, utilizes clear water as scouring media in boring procedure;

D. in the time that inclined drill (9) creeps into lower roof position, utilize and force whipstock to carry out deflecting boring, when drilling kick-off section creep under close on track coal seam (11) in and change into after level, continue horizontal drilling and hole, until preseting length completes creeping into of a boring;

E. complete after the creeping into an of boring, repeating step c, d many times, creep into multiple boring, until complete one group of boring in this drill site;

F., methane gas extraction pipeline is installed, is closed on the extraction of coal-bed gas under one group of boring in this drill site is carried out, the gas of extraction is transported to appointed place by the gas tube (3) being laid in working face haulage way (1);

G. along with thin seam working surface constantly advances, arrange a drill site along the first drill site of thin seam working surface direction of propulsion distance every 15～30m, repeating step c, d, e, f, complete the gas pumping that closes on coal seam under all.