CN103696800A - Drilling, cutting, pressing and pumping method - Google Patents

Abstract

The invention provides a drilling, cutting, pressing and pumping method which is suitable for gas extraction of coal seams which are high in gas and low in gas permeability. The drilling, cutting, pressing and pumping method comprises punching a drill hole according to the design requirements through a drilling machine; replacing a hydraulic seam cutting drill bit after a drill rod is withdrawn, continuing to drill to the bottom of the drill hole and withdrawing the drill rod to perform hydraulic seam cutting; sealing the drill hole and performing gas drainage after the hydraulic seam cutting is achieved; switching a drainage pipeline into a pulse water injection pump station when the gas drainage capacity is in the attenuation trend and fracturing the coal seams in a pulse hydraulic fracturing mode. According to the drilling, cutting, pressing and pumping method, the effective influence range of a single hole of gas extraction drilling of the coal seams can be increased by more than 30%, the gas flow of the single hole can be improved by more than 30%, the gas extraction rate can be improved by more than 20%, the operation is simple, the influence range of drilling pressure relief can be improved, and the concentration and the efficiency of the gas extraction of the drilling can be improved.

Description

A method of drilling, cutting, pressing and pumping

technical field

The invention relates to a method of drilling, cutting and pressure pumping, which is particularly suitable for gas pumping of high-gas and low-permeability coal seams in underground coal mines.

Background technique

The geological conditions of my country's coal mines are complex, high-gas coal seams account for 50-70%, and high-gas low-permeability coal seams account for about 70% of them. The mining of high-gassy and low-permeability coal seams is often accompanied by a large amount of gas gushing, especially with the efficient intensification of coal production and the increase of mining depth, the amount of gas gushing is increasing, and the threat of gas explosion and gas outburst is also increasing. Gas disasters have become the most important factor restricting the development of intensive mining technology and safe production in colleges and universities. Therefore, how to solve the problem of gas gushing in the process of mining high-gas coal seams is of great significance to the safe production of coal mines.

The main measure to solve the problem of gas gushing in the process of mining high gas and low permeability coal seam is gas drainage. Through gas drainage, not only can the gas gushing out during coal seam mining be effectively reduced, ensuring the safety of coal mine production; at the same time, the high-concentration gas extracted can be utilized to realize dual-energy mining. However, high-gassy and low-permeability coal seams have poor permeability, and conventional drainage is difficult and ineffective, so technical measures for pressure relief and permeability enhancement are required. Conventional gas drainage methods are difficult to play a role. The main problems are: the effective range of drilling is small, the workload of drilling construction on the working face is large, and the drainage efficiency is low.

Contents of the invention

Technical problem: The purpose of the present invention is to overcome the deficiencies in the prior art, and provide a simple method, which can improve the influence range of borehole pressure relief, improve the concentration of gas drainage in boreholes and the efficiency of gas drainage. method.

Technical solution: The drilling, cutting, pressing and pumping method of the present invention comprises the following steps:

a. Use a drilling rig to drill a hole in the coal seam in front of the coal mining or excavation face to the design depth;

b. Withdraw the drill pipe, replace the hydraulic slitting drill bit and continue drilling until reaching the bottom of the borehole, then retreat the drill pipe to perform hydraulic slitting at intervals, forming multiple annular main cracks in the borehole; perform hydraulic slitting at intervals The time is 20 minutes;

c. After the hydraulic cutting is completed, send the Y-shaped tee pipe bound with polyurethane sealing tape at the front into the borehole, and then send the grout return pipe and the grouting pipe into the borehole. The pipe, grouting pipe and grouting pipe enter the drilling section and bind the polyurethane sealing tape to block the borehole opening. Set up the pumping pipe ball valve and the fracturing pipe ball valve on the inlet pipe section of the Y-shaped tee pipe respectively. The length of the hole sealing section of the borehole is 25% to 40% of the borehole length;

d. Connect the gas drainage pipe network, open the drainage pipe ball valve on the Y-shaped three-way pipe, and use negative pressure to pump out the gas, and the negative pressure at the hole hole should not be lower than 20KPa;

e. When the pressure gauge shows that the gas drainage volume shows a decreasing trend, close the drainage pipe ball valve on the Y-shaped three-way pipe, open the fracturing pipe ball valve on the Y-shaped three-way pipe, and switch the drainage pipe to pulsating water injection The pump station uses pulsating water to perform hydraulic fracturing on the coal seam. The hydraulic fracturing cracks expand along the main cracks formed by the hydraulic slits to form secondary cracks; after the fracturing is completed, close the fracturing ball valve and connect the pipeline To the drainage pipe network, open the ball valve of the drainage pipe, and use the negative pressure to continue to pump the gas out of the borehole.

The Y-shaped tee pipe includes a drainage pipe on the same straight line as the main pipe, a fracturing pipe connected to the main pipe through a curved pipe section and parallel to the drainage pipe, the diameter of the drainage pipe and the fracturing pipe are equal, and the pumping The center distance between the discharge pipe and the fracturing pipe is 1.5 to 3 times the diameter of the pipe. The end of the discharge pipe and the fracturing pipe is sealed, and there are eyes on the pipe wall 1 to 3m away from the end sealing section.

Beneficial effects, due to the adoption of the above scheme, the present invention can increase the effective range of influence of a single hole in coal seam gas drainage drilling by more than 30%, increase the gas flow rate of a single hole by more than 30%, and increase the gas drainage rate by more than 20%. The rapid drainage of gas in front of the front can realize the safe and rapid advancement of the working face. The main advantages are:

(1) The main fractures formed by hydraulic cutting can become the guiding fractures of hydraulic fracturing in the later stage, which is conducive to the formation of fractures;

(2) The synergistic effect of hydraulic cutting and hydraulic fracturing realizes the "secondary increase" of gas and increases the flow and concentration of gas. It can realize the rapid drainage of gas in front of the working face, and at the same time, the stress in front of the working face can also be reduced, forming an effective pressure relief space, so as to realize the rapid advancement of the working face;

(3) The invention is easy to operate, improves the gas drainage rate, realizes safe gas drainage, and improves economic benefits.

Description of drawings

Fig. 1 is a structural diagram of the present invention.

Fig. 2 is a structural diagram of a Y-shaped three-way pipe.

In the figure: 1, Y-type tee pipe; 1-1, drainage pipe; 1-2, fracturing pipe; 1-3, drainage pipe ball valve; 1-4, fracturing pipe ball valve; 2, coal seam; 3 1. Grout return pipe; 4. Front and rear polyurethane sealing sections; 5. Main crack; 6. Secondary crack; 7. Drilling; 8. Grouting section; 9. Grouting tube.

Detailed ways

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

Drilling, cutting, pressing and pumping method of the present invention, concrete steps are as follows:

a. First, use a drilling rig to drill a drill hole 7 to the design depth in the coal seam 2 in front of the coal mining or driving face;

b. Exit the drill pipe, replace the hydraulic slitting drill bit and continue drilling until reaching the bottom of the borehole, and retreat the drill pipe to perform hydraulic slitting at intervals to form multiple annular main cracks 5 in the borehole; perform hydraulic slitting at the intervals The time is 20 minutes; the coal body is artificially disturbed through the slit to form a space for pressure relief and permeability enhancement, and improve the air permeability of the coal seam;

c. After the hydraulic cutting is completed, the opening of the drill hole 7 is blocked. The length of the sealing section is 25-40% of the drilling length. into the borehole 7, then send the grout return pipe 3 and the grout injection pipe 9 into the borehole 7, and at the same time bind the polyurethane sealing hole when the Y-shaped tee pipe 1, the grout injection pipe 9 and the grout return pipe 3 enter the drill hole section belt, respectively set the discharge pipe ball valve 1-3 and the fracturing pipe ball valve 1-4 on the inlet pipe section of the Y-shaped tee pipe, and set the switch valve on the outlet section of the grouting pipe 9 and the grouting pipe 3, Use the grouting pump to connect the grouting pipe 9 to inject the cement slurry into the borehole 8 blocked by the front and rear polyurethane sealing sections 4, and when the grout flows out of the grouting pipe 3, close the valve on the grouting pipe 3 and continue grouting 1 Turn off the grouting pump after ~2 minutes, and complete the plugging of the front and rear polyurethane sealing sections 4 to plug the borehole;

The Y-shaped tee pipe includes a drainage pipe 1-1 on the same straight line as the main pipe, a fracturing pipe 1-2 connected to the main pipe through a curved pipe section and parallel to the drainage pipe, and the drainage pipe 1- 1 is equal to the diameter of the fracturing pipe 1-2, the center distance between the drainage pipe 1-1 and the fracturing pipe 1-2 is 1.5 to 3 times the pipe diameter, and the drainage pipe 1-1 and the fracturing pipe 1-2 2. The end of the seal is sealed, and there are eyes on the pipe wall 1-3m away from the end seal;

d. Connect the gas drainage pipe network, open the drainage pipe ball valve 1-3 on the Y-shaped three-way pipe 1, and use negative pressure to pump out the gas, and the negative pressure at the bore hole should not be lower than 20KPa;

e. When the pressure gauge shows that the gas drainage volume shows a decreasing trend, close the drainage pipe ball valve on the Y-shaped three-way pipe, open the fracturing pipe ball valve on the Y-shaped three-way pipe, and switch the drainage pipe to pulsating water injection The pumping station uses pulsating water to perform hydraulic fracturing on the coal seam, and the hydraulic fracturing cracks expand along the main cracks formed by the hydraulic slits to form secondary cracks 6; after the fracturing is completed, close the fracturing ball valves 1-4, Connect the pipeline to the drainage pipe network, then open the drainage pipe ball valve 1-3, and continue to extract the gas from the borehole 7 by using negative pressure. In this way, the "secondary increase" of gas is realized, and the gas flow and concentration are improved.

Claims (2)

1. brill cuts to press and takes out a method, it is characterized in that, comprises the steps:

A, utilize rig to mining or the coal seam in driving face the place ahead is made a call to one and holed to projected depth;

B, exit drilling rod, change hydraulic slotted liner technique drill bit and continue to creep into, until arrive foot of hole, retreat drilling rod interval and carry out hydraulic slotted liner technique, in boring, form the main crack of a plurality of annulars; The time that hydraulic slotted liner technique is carried out at described interval is 20min;

After c, hydraulic slotted liner technique finish, the Y-shaped three-way pipe that front portion is banded with to polyurethane sealing pore area is sent in boring, again return pipe and Grouting Pipe are veered away in boring, at Y-shaped three-way pipe, Grouting Pipe and return pipe, enter boring section colligation polyurethane sealing pore area simultaneously, drilling orifice is blocked, releasing pipe ball valve and pressure break pipe ball valve are set respectively on the entrance pipeline section of Y-shaped three-way pipe, and the length of described drilling orifice sealing of hole section is 25～40% of boring length;

D, connection gas drainage under suction pipe network, open the releasing pipe ball valve on Y-shaped three-way pipe, utilizes negative pressure that gas is extracted out, and drilling orifice negative pressure is not less than 20KPa;

E, when pressure meter shows that gas drainage amount is attenuation trend, close the releasing pipe ball valve on Y-shaped three-way pipe, open the pressure break pipe ball valve on Y-shaped three-way pipe, extraction pipeline is switched to pulsed infusion pumping plant, by pulsation water, fracturing is carried out in coal seam, fracturing crack is expanded along the formed main crack of hydraulic slotted liner technique, forms secondary interstice; After pressure break finishes, close pressure break ball valve, pipeline is connected to extraction pipe network, then opens releasing pipe ball valve, utilize negative pressure to continue gas from the interior extraction of holing.

2. a kind of brill according to claim 1 cuts the method for taking out of pressing, it is characterized in that: described Y-shaped three-way pipe comprises with main body tube the releasing pipe on same straight line, the pressure break pipe that is communicated with main body tube and parallels with releasing pipe through a bending tube section, releasing pipe and pressure break pipe equal diameter, centre distance between releasing pipe and pressure break pipe is caliber 1.5～3 times, the end sealing of releasing pipe and pressure break pipe, has presbyopia on the tube wall apart from end sealing section 1～3m.

Images