Hydrofracture roof cutting and roadway protecting method based on directional drilling stopping line

Abstract

The invention relates to a hydraulic fracturing roof cutting roadway protection method based on a directional drilling stopping line, which comprises the following steps of: 1, determining a roadway or a drill site for implementing directional drilling according to the arrangement condition of a roadway at the periphery of the stopping line; 2, determining a target horizon and an area, and judging the position of hard rock of an overlying rock layer of a coal seam based on a working face drilling histogram and a key layer theory; and step 3, designing a directional drilling track route according to the position of the target rock layer, and determining a segmented hydraulic fracturing position and the like. According to the method, firstly, the directional drilling target layer position and the spatial position are determined, the directional drilling construction technology is used, directional long drilling is carried out in the target layer position, one directional long drilling hole is used for replacing a traditional scheme that multiple drilling holes are constructed in the target layer position in a roadway when pre-splitting blasting or hydraulic fracturing is carried out for roof cutting, and the method has the advantages that the drilling work amount is small, and the construction efficiency is high. And the operation is convenient.

Description

Technical Field

[0001] The invention relates to the field of coal seam mining, and in particular to a method for cutting top and protecting lanes based on hydraulic fracturing of a directional drilling stop mining line. Background Art

[0002] With the increase in the scope and depth of coal seam mining, mining engineering problems under complex geological conditions are becoming increasingly prominent. One of them is that when there are thick and hard rock layers in the overburden of the mining area, they can play a bearing role in the overburden. After the coal mining face stops mining, the overburden forms a long cantilever beam with coal pillars as fulcrums. The coal pillars bear a large supporting force. When the roadway is close to the stop line of the coal mining face and the size of the reserved roadway protection coal pillar is insufficient, the advanced support stress and the mining stress generated by the rock fracture will have a stress disturbance effect on the main roadway in front of the working face, which may destroy the stability of the main roadway in the mining area, causing the roadway to deform significantly, making it more difficult to maintain the safety and stability of the roadway, and affecting the normal production of the mine.

[0003] Pre-splitting the roof by using pre-splitting blasting or hydraulic fracturing technology at the stop-mining line position of the working face can advance the treatment of the overlying hard rock layer, cut off the propagation path of the supporting pressure, achieve the purpose of optimizing the stress environment, and realize the top cutting and lane protection. At present, the commonly used methods for top cutting and pressure relief are pre-splitting blasting and hydraulic fracturing, but the implementation of pre-splitting blasting has problems such as arranging many drill holes, cumbersome charging process, and detonation pollution of the underground environment. Traditional hydraulic fracturing construction is generally a joint arrangement of machine lanes and air lanes. During the hydraulic fracturing construction, it is parallel to the coal mining face recovery, which affects production. Based on this, the present invention proposes a method for cutting the top and protecting the lane by hydraulic fracturing of the stop-mining line based on directional drilling. Summary of the invention

[0004] In order to overcome the existing problems, the present invention provides a method for cutting top and protecting lanes based on directional drilling and hydraulic fracturing of a stop-mining line, which solves the problem that the advanced support pressure of the coal mining face affects the stability of the main lane. Based on the directional drilling technology, construction can be carried out in the lanes around the stop-mining line or in the drilling site of the machine and ventilation lane, and the target rock formation can be accurately located. Hydraulic fracturing technology can be used to achieve top cutting and pressure relief to protect the stability of the dynamic pressure lane.

[0005] The technical solution of the present invention is: a method for hydraulic fracturing and cutting tops to protect lanes based on a directional drilling stop production line, comprising the following steps: Step 1, determining a lane or drilling site for implementing directional drilling according to the arrangement of lanes around the stop production line;

[0006] Step 2: Determine the target layer and area, based on the drilling column chart of the working face and the key layer theory, determine the location of the hard rock in the overlying stratum of the coal seam;

[0007] Step 3: Design the directional drilling trajectory and determine the segmented hydraulic fracturing location according to the target rock formation;

[0008] Step 4: Take the starting point of the line as the drilling point, use a directional drill at the implementation site, and use the step-by-step rotary hole expansion technology to construct. After reaching the designed distance, withdraw the drilling tool from the hole;

[0009] Step 5: Prefabricate transverse grooves by using a KZ54 groove drill bit to prefabricate transverse grooves in the hard section at the bottom of the hole;

[0010] Step 6: Connect the thorn-type packer to the high-pressure oil pipe in sequence, and use the high-pressure oil pipe to deliver the thorn-type packer to the drilling groove;

[0011] Step 7: Use a grouting pump to inject high-pressure water into the high-pressure oil pipe to continuously pressurize the packer to achieve the purpose of sealing the transverse groove section;

[0012] Step 8: Connect a high-pressure grouting pump, a water pressure gauge and a high-pressure oil pipe to perform water injection fracturing on the isolation section. During the fracturing process, the water pressure gauge is used to monitor the change of the pump pressure.

[0013] Step 9: When the ultimate strength of the hard rock formation is reached, cracks appear in the rock formation and the pressure is stabilized for 5-10 minutes; stop pressurizing, and after the fluid pressure is completely released, move the thorn-type packer to the second fracturing position through the high-pressure oil pipe, and perform the second segmented hydraulic fracturing work according to steps 6-9; continue in this way until the hydraulic fracturing work at the fracturing position is completed.

[0014] Beneficial effects: 1. The method of the present invention first determines the target layer and spatial position of the directional drilling, uses the directional drilling construction technology, implements directional long drilling in the target layer, and uses one directional long drilling hole to replace the traditional pre-splitting blasting or hydraulic fracturing to implement the top cutting, which is a scheme of constructing multiple boreholes in the tunnel to the target layer. It has the advantages of small drilling workload and convenient operation.

[0015] 2. The device of the present invention uses a thorn-type packer to replace the traditional packer and cutter to complete the process of staged and sequential fracturing in the same borehole. In the implementation process, the process of positioning and installing the packer is eliminated, simplifying the operation.

[0016] 3. The present invention is based on directional drilling technology and can be constructed in tunnels around the stop-production line or in the drilling site of the machine-ventilation tunnel. It can accurately locate the target rock layer and use hydraulic fracturing technology to achieve top cutting and pressure relief to protect the stability of the dynamic pressure tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flow chart of the present invention;

[0018] Figure 2 It is a schematic diagram of the thorn type packer in the present invention;

[0019] Figure 3It is a schematic diagram of the downhole directional drilling staged hydraulic fracturing process in the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, but the protection scope and application scope of the present invention are not limited.

[0021] like Figure 1-3 As shown, a method for cutting top and protecting lanes based on hydraulic fracturing of a directional drilling stop production line mainly includes the following steps:

[0022] Step 1: Determine the tunnel or drilling site for directional drilling based on the layout of the tunnels around the stop-mining line;

[0023] Step 2: Determine the target layer and area, based on the drilling column chart of the working face and the key layer theory, determine the location of the hard rock in the overlying stratum of the coal seam;

[0024] Step 3: Design the directional drilling trajectory and determine the segmented hydraulic fracturing location according to the target rock formation;

[0025] Step 4: Take the starting point of the line as the drilling point, use a directional drill at the implementation site, and use the step-by-step rotary hole expansion technology to construct. After reaching the designed distance, withdraw the drilling tool from the hole;

[0026] Step 5: Prefabricate transverse grooves by using a KZ54 groove drill bit to prefabricate transverse grooves in the hard section at the bottom of the hole;

[0027] Step 6: Connect the thorn-type packer to the high-pressure oil pipe in sequence, and use the high-pressure oil pipe to deliver the thorn-type packer to the drilling groove;

[0028] Step 7: Use a grouting pump to inject high-pressure water into the high-pressure oil pipe to continuously pressurize the packer to achieve the purpose of sealing the transverse groove section;

[0029] Step 8: Connect a high-pressure grouting pump, a water pressure gauge and a high-pressure oil pipe to perform water injection fracturing on the isolation section. During the fracturing process, the water pressure gauge is used to monitor the change of the pump pressure.

[0030] Step 9: When the ultimate strength of the hard rock formation is reached, cracks appear in the rock formation and the pressure is stabilized for 5-10 minutes; stop pressurizing, and after the fluid pressure is completely released, move the thorn-type packer to the second fracturing position through the high-pressure oil pipe, and perform the second segmented hydraulic fracturing work according to steps 6-9; continue in this way until the hydraulic fracturing work at the fracturing position is completed.

[0031] The above description of the disclosed embodiments enables those skilled in the art to implement and use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit and scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A method for cutting top and protecting lanes based on hydraulic fracturing of directional drilling stop production line, characterized in that: The following steps are involved: Step 1: Determine the tunnel or drilling site for directional drilling based on the layout of the tunnels around the stop-mining line; Step 2: Determine the target layer and area, based on the drilling column chart of the working face and the key layer theory, determine the location of the hard rock in the overlying stratum of the coal seam; Step 3: Design the directional drilling trajectory and determine the segmented hydraulic fracturing location according to the target rock formation; Step 4: Take the starting point of the line as the drilling point, use a directional drill at the implementation site, and use the step-by-step rotary hole expansion technology to construct. After reaching the designed distance, withdraw the drilling tool from the hole; Step 5: Prefabricate transverse grooves by using a KZ54 groove drill bit to prefabricate transverse grooves in the hard section at the bottom of the hole; Step 6: Connect the thorn-type packer to the high-pressure oil pipe in sequence, and use the high-pressure oil pipe to deliver the thorn-type packer to the drilling groove; Step 7: Use a grouting pump to inject high-pressure water into the high-pressure oil pipe to continuously pressurize the packer to achieve the purpose of sealing the transverse groove section; Step 8: Connect a high-pressure grouting pump, a water pressure gauge and a high-pressure oil pipe to perform water injection fracturing on the isolation section. During the fracturing process, the water pressure gauge is used to monitor the change of the pump pressure. Step 9: When the ultimate strength of the hard rock formation is reached, cracks appear in the rock formation and the pressure is stabilized for 5-10 minutes; stop pressurizing, and after the fluid pressure is completely released, move the thorn-type packer to the second fracturing position through the high-pressure oil pipe, and perform the second segmented hydraulic fracturing work according to steps 6-9; continue in this way until the hydraulic fracturing work at the fracturing position is completed.

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