Gas extraction drilling device for upward drilling of downhole drilling site and operation method

Abstract

The application discloses a gas extraction drilling blowout preventer for upward drilling in a downhole drilling site and an operating method thereof. The device comprises an orifice catcher and a drilling machine. The drilling machine drills a borehole in the rock layer and coal seam at the top of the downhole drilling site to extract coal seam gas. A drilling connection pipe is arranged at the front end of the catcher body and is placed in the rock drilling hole upward. A drill rod with a drill bit is inserted into the catcher body through the tail end of the catcher body and is then pulled out from the inner hole of the drilling connection pipe. An adjustable length positioning top rod is arranged between the tail end of the catcher body and the drill rod holder of the drilling machine. The positioning top rod is used to position the orifice catcher by pressing against the catcher body. A water supply interface, a gas output interface and a drilling residue discharge interface are sequentially arranged in the inner cavity of the catcher body from front to tail. The water supply interface is connected with a water supply pipeline to spray water into the inner cavity for dust removal. The gas output interface is connected with an extraction current collector to extract and receive the coal seam gas. The drilling residue discharge interface is connected with a gas-water residue separator to receive the drilled rock residue and coal residue.

Description

TECHNICAL FIELD

[0001] The present application relates to a gas extraction drilling blowout preventer for upward drilling in a downhole drilling field and an operating method. BACKGROUND

[0002] Article 32 of the "Coal and Gas Outburst Prevention Regulations" provides that "areas where the coal seam gas pressure reaches or exceeds 2 MPa, and areas where dynamic phenomena such as jetting and drilling occur during drilling, shall take measures to prevent gas overrun and jetting and drilling injuries, or use remote-controlled drilling machines for construction".

[0003] The existing blowout prevention technology mainly relies on installing a blowout preventer during drilling to prevent drilling jetting and gas overrun. The blowout preventer is mainly composed of a borehole catcher and a coal-water separator. The borehole catcher with a casing is installed after the borehole is opened to a certain depth during cross-layer drilling. A drill tool with a fixed diameter is used during drilling. The borehole catcher is connected to the coal gas separator through a soft tube. The drill cuttings and gas discharged into the separator are separated. The gas is extracted through the extraction pipeline, and the drill cuttings flow out through the discharge port.

[0004] As upward drilling for gas extraction in a downhole, the objective shortcomings of the existing technology are:

[0005] (1) When the drill bit drills into a soft coal seam, the borehole is prone to collapse, causing poor return slag passage. When the drill tool reciprocates, the accumulated gas is suddenly jetted out.

[0006] (2) The borehole catcher of the blowout preventer is not tightly sealed with the drill rod. The conventional blowout preventer drill rod seal often uses materials such as leather pads, which are prone to deformation under the friction of the drill rod, causing the gap to continuously expand and causing gas leakage.

[0007] (3) The volume of the separator is limited. When the amount of gas jetted out is large, it is easy to overflow from the separator or even knock out the borehole catcher, causing abnormal gas around.

[0008] (4) When the amount of gas emitted during drilling is large, it is easy to leak from the tail end of the drill rod.

[0009] (5) Coal dust generated during drilling can pollute the extraction system and even overflow from the borehole catcher and other places, causing environmental pollution. SUMMARY

[0010] The purpose of the present application is to provide a gas extraction drilling blowout preventer for upward drilling in a downhole drilling field and an operating method. By setting an adjustable positioning jack between the borehole catcher and the drill machine hydraulic clamp, the borehole catcher is prevented from being knocked out of the borehole when the jetting is severe.

[0011] In order to achieve the above-mentioned purpose, the scheme of the present application is:

[0012] The gas extraction drilling hole blowout preventer of the upward drilling hole of the downhole drilling site comprises an orifice catcher and a drilling machine, and the drilling machine drills the rock layer and the coal layer at the top of the downhole drilling site to extract the coal seam gas, wherein: the orifice catcher comprises a catcher body, a drilling connection pipe is arranged at the front end of the catcher body, the drilling connection pipe is communicated with the inner cavity of the catcher body, the drilling connection pipe is arranged in the rock layer drilling hole upwardly, the drilling rod with a drill bit of the drilling machine is arranged in the tail end of the catcher body, penetrates through the inner cavity of the catcher body, penetrates out of the inner hole of the drilling connection pipe, and drills into the coal layer, an adjustable length positioning top rod is arranged between the tail end of the catcher body and the drill rod clamp of the drilling machine, the positioning top rod is arranged on the catcher body to position the orifice catcher, a sealing sleeve is arranged between the drill rod and the tail end of the catcher body, the drill rod rotates in the sealing sleeve, the inner cavity of the catcher body is sequentially provided with a water supply interface, a gas output interface and a drilling residue discharge interface from front to tail, the water supply interface is connected with a water supply pipeline to spray water into the inner cavity for dust removal, the gas output interface is connected with an extraction current collector for extracting and receiving the coal seam gas, and the drilling residue discharge interface is connected with a gas-water residue separator for receiving the drilled rock residue and coal residue.

[0013] Further, the positioning top rod is two threaded rods arranged on both sides of the drill rod of the drilling machine, two adjusting nuts are arranged on the drill rod clamp of the drilling machine, the two threaded rods are screwed into the two adjusting nuts respectively, and the length of the threaded rods protruding out is adjusted by rotating the adjusting nuts to adjust the positioning of the catcher body.

[0014] Further, the gas-water residue separator is provided with a gas outlet connected with the extraction current collector through a pipeline to discharge the gas flowing into the extraction current collector with the coal residue.

[0015] Further, the gas-water residue separator is provided with an outer end closed telescopic expander arranged on the side wall opposite to the receiving inlet of the gas-water residue separator to automatically adjust the volume of the cabin of the gas-water residue separator, a filter screen is arranged between the receiving inlet of the gas-water residue separator and the bottom plate, a drainage port is arranged on the bottom plate of the gas-water residue separator, and a residue discharge port is arranged on the side wall of the gas-water residue separator at the inclined lower end of the filter screen.

[0016] Further, the gas-water residue separator is provided with a float ball valve on the drainage port and a control valve on the residue discharge port, when the water level reaches a certain height, the float ball valve opens to drain the accumulated water, and the control valve opens at a certain time to clean the drilling residue.

[0017] Further, the sealing sleeve is a cast iron sealing sleeve embeddedly installed with the tail end of the catcher body.

[0018] Further, the diameter of the rock layer drilling hole is at least 120 mm, and the depth of the rock layer drilling hole is at least 2000 mm.

[0019] The application discloses a gas extraction drilling blowout prevention operation method for upward drilling of a downhole drilling site, and is based on an operation method of a gas extraction drilling blowout prevention device.

[0020] One, a 120mm diameter drill bit is used to drill a hole in a rock layer to a depth of 2m, a drilling connection pipe at the front end of the catcher body is inserted into the rock layer drilling hole, and a drilling machine is arranged at the rear end side of the catcher body;

[0021] Two, a drill rod with a drill bit is inserted into the catcher, and meanwhile, two adjustable length positioning jacks are arranged between the tail end of the catcher body and the drill rod holder of the drilling machine to press against and position the hole catcher;

[0022] Three, the water supply interface, gas output interface and drilling residue discharge interface of the hole catcher are respectively connected with a water supply pipeline, a gas extraction current collector and a gas-water residue separator through pipelines.

[0023] The drilling gas extraction stage operation is: the drilling machine is started to drill into the rock layer and coal seam by using compressed air to discharge powder; when drilling into the coal seam, the water supply interface is opened to spray water into the inner cavity of the catcher body to reduce dust, and meanwhile, the gas extraction current collector is started to extract gas.

[0024] Further, the two adjustable length positioning jacks are two threaded rods, the two threaded rods are arranged on the two sides of the drill rod of the drilling machine, two adjusting nuts are arranged on the drill rod holder of the drilling machine, the two threaded rods are respectively screwed into the two adjusting nuts, and the length of the threaded rods extending out of the adjusting nuts is adjusted by rotating the adjusting nuts to realize the positioning adjustment of the catcher body.

[0025] The application has the following beneficial effects: by arranging the adjustable positioning jacks between the hole catcher and the hydraulic clamp of the drilling machine, the hole catcher is prevented from being knocked out of the drilling hole when the blowout is serious. In the process of drilling through the coal seam, the application is used to realize the drilling and extraction simultaneously, the coal seam gas pressure in the drilling construction area is reduced, and the risk of gas blowout is reduced. The effects include:

[0026] (1) The drilling and extraction simultaneously are realized, the gas is directly extracted by using the drilling tool during drilling, the coal seam gas pressure is reduced, and the number of coal seam blowout during drilling is reduced;

[0027] (2) By using the application, most of the gas sprayed out of the drilling hole directly enters the extraction system, the gas overrun can be effectively avoided, the coal dust sprayed out of the drilling hole is reduced by spraying dust, and thus the dust pollution to the environment is avoided;

[0028] (3) The telescopic separator can effectively increase the volume and accommodate more instantaneous gushing gas, the blowout prevention capacity is greatly improved, and the gas overflow caused by the limited volume is avoided.

[0029] The application will be described in detail below with reference to the drawings and embodiments. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0031] Example 1:

[0032] Blowout prevention devices for gas drainage boreholes drilled upwards in downhole drilling sites, such as... Figure 1 As shown, the gas extraction borehole blowout prevention device includes a drilling site 1, a borehole catcher 2, and a drilling rig 3, which are set up in the underground excavation. The drilling rig 3 includes a fixed drilling rig runway 301. A drill rod clamp 302 and a drill rod power head 303 are respectively set on the front and rear of the drilling rig runway 301. The drill rod clamp 302 is used to clamp the drill rod to keep the drill rod 304 stable, and the drill rod power head 303 is used to drive the drill rod to rotate. The drilling rig drills boreholes to the top rock strata 4 and coal seam 5 in the underground drilling site to extract coal seam gas. The drill rod power head 303 is controlled to rotate by the drilling rig control console 307. As a traditional drilling method, the drill rod power head 303 is also connected to a water supply pipeline 305 and an air pressure pipeline 306 to provide cooling water and air pressure to the drill bit of the drill rod. The wellhead catcher 2 includes a catcher body 201. A drilling connection pipe 202, a multi-segment threaded copper pipe with a diameter of 120mm, is located at the front end of the catcher body 201. The drilling connection pipe 202 communicates with the inner cavity of the catcher body and is positioned upwards in a rock borehole 401. The borehole diameter is at least 120mm and the depth is at least 2000mm. The drill rod 304 of the drilling rig 3, equipped with a drill bit, passes through the tail end of the catcher body, exits through the inner cavity of the catcher body, and drills into the coal seam via the inner hole of the drilling connection pipe 202. An adjustable-length positioning rod 6 is provided between the tail end of the catcher body and the drill rod holder 302 of the drilling rig. The positioning rod 6 holds the catcher body 201 in place, preventing the wellhead catcher from being ejected from the borehole in case of severe blowout. A sealing sleeve 7 is provided between the drill rod 304 and the tail end of the catcher body, and the drill rod 304 rotates within the sealing sleeve 7. The capture device is equipped with a water supply interface 203, a gas output interface 204, and a drill cuttings discharge interface 205 arranged sequentially from front to back in its internal cavity. The water supply interface 203 is connected to a water supply pipeline 305 via a valve to spray water into the internal cavity for dust removal. The gas output interface 204 is connected to an extraction manifold 8 via a valve to extract and receive gas from the coal seam. The extraction manifold 8 is connected to a gas treatment station via an extraction pipeline. The drill cuttings discharge interface 205 is connected to a gas-water-slag separator 9 to receive rock cuttings and coal slag from the drill.

[0033] Wherein: the positioning top rod 6 is two threaded rods, two threaded rods 6 are arranged on both sides of the drill rod 304 of the drilling machine, two adjusting nuts 10 are arranged on the drill rod holder 302 of the drilling machine, the two adjusting nuts 10 are rotatably fixed on the drill rod holder 302, the two threaded rods 6 are screwed into the two adjusting nuts 10 respectively, and the length of the threaded rod 6 protruding is adjusted by rotating the adjusting nut 10 to realize the positioning adjustment of the catcher body.

[0034] Since the gas-water residue separator will enter the gas with the drilling residue, an air outlet 901 is arranged on the gas-water residue separator 9, the gas flowing into the coal residue is discharged into the extraction collector 8 through the valve connected by the pipeline.

[0035] In the embodiment: the gas-water residue separator is provided with an outer end closed telescopic expander 903 on the side wall opposite to the receiving inlet 902 for receiving the drilling rock residue and coal residue, which is used to automatically adjust the cabin volume of the gas-water residue separator 9, a filter screen 904 is arranged between the receiving inlet 902 of the gas-water residue separator 9 and the bottom plate of the gas-water residue separator, a drainage outlet 905 is arranged on the bottom plate of the gas-water residue separator, and a residue discharge outlet 906 is arranged on the side wall of the gas-water residue separator at the inclined lower end of the filter screen. Wherein: the gas-water residue separator is provided with a float ball valve on the drainage outlet, and a control valve is arranged on the residue discharge outlet, when the water level reaches a certain height, the float ball valve opens to discharge the accumulated water, and the control valve opens regularly to clean the drilling residue.

[0036] In the embodiment: the sealing sleeve 7 is a wear-resistant cast iron sealing sleeve, which prevents the sealing damage of the drill rod and the hole capture device caused by long-time drilling, and the cast iron sealing sleeve is embeddedly installed with the tail end of the catcher body.

[0037] Embodiment 2:

[0038] A gas extraction drilling blowout prevention operation method of an upward drilling well site is an operation method based on the gas extraction drilling blowout prevention device of embodiment 1, therefore, the content of the embodiment is applicable to the present embodiment, and the method comprises a preparation stage operation and a drilling gas discharge stage operation, and is characterized in that the preparation stage operation is:

[0039] One, a drill bit with a diameter of 120 mm is used to drill a hole in the rock layer to a depth of 2 m, a drilling hole connecting pipe at the front end of the catcher body is inserted into the rock layer drilling hole, and the drilling machine is placed at the rear end side of the catcher body.

[0040] Two, the drill rod with the drill bit is inserted into the catcher, and at the same time, two adjustable length positioning top rods are placed between the tail end of the catcher body and the drill rod holder of the drilling machine to position the hole capture device.

[0041] Third, the water supply interface, gas output interface and drilling slag discharge interface of the orifice catcher are connected to the water supply pipeline, the gas extraction current collector and the gas-water-slag separator through pipelines respectively;

[0042] The drilling gas discharge stage operation is: starting the drilling machine to drill into the rock and coal seam by using compressed air to discharge powder; when drilling into the coal seam, the water supply interface is opened to spray water into the inner cavity of the catcher body to reduce dust, and the gas extraction current collector is started to extract gas.

[0043] Among them: the two adjustable length positioning jacks are two threaded rods, which are arranged on both sides of the drilling machine drill rod, and two adjusting nuts are arranged on the drill rod clamp of the drilling machine, and the two threaded rods are screwed into the two adjusting nuts respectively, and the length of the threaded rods extending out is adjusted by rotating the adjusting nuts to realize the positioning adjustment of the catcher body.

[0044] The above-mentioned downhole drilling site upward drilling gas extraction drilling hole blowout prevention device and operation method embodiment, the device is an integrated blowout prevention device, the gas sprayed when drilling through coal is mainly extracted through the orifice catcher, the connecting pipe and the extraction pipeline, and the coal dust generated when drilling through coal is sprayed and dusted in the orifice catcher, and the remaining small amount of gas, drilling cuttings and the like are discharged through another connecting pipe into the telescopic separator, the water and drilling cuttings are filtered and discharged into the roadway sedimentation tank, the drilling cuttings in the sedimentation tank are cleaned regularly, the water is discharged through the water ditch, the drilling slag is deposited in the separation barrel, the device realizes drilling and extraction at the same time, reduces the coal seam gas pressure in the drilling construction area, reduces the risk of gas blowout, and when drilling in the rock formation, the water supply pipeline is connected to realize water powder discharge; when drilling in the coal seam, the compressed air pipeline is connected to realize compressed air powder discharge; when drilling in the coal seam with large gas emission, the gas extraction current collector is connected to realize rapid gas extraction.

[0045] The embodiment avoids the orifice catcher from being knocked out of the drilling hole when the blowout is serious by setting an adjustable positioning jack between the orifice catcher and the drilling machine hydraulic clamp. The invention is used during the drilling process through coal to realize drilling and extraction at the same time, reduce the coal seam gas pressure in the drilling construction area, and reduce the risk of gas blowout.

Claims

1. A method for preventing blowout in a gas drainage borehole drilled upwards in an underground drilling site, comprising a blowout prevention device for a gas drainage borehole drilled upwards in an underground drilling site, the device having a borehole catcher and a drilling rig, the drilling rig drilling into the top rock strata or coal seam in the underground drilling site to extract coal seam gas, characterized in that, The orifice catcher includes a catcher body with a drilling connection pipe at its front end, which communicates with the inner cavity of the catcher body. The drilling connection pipe is positioned upwards in the rock borehole. A drill rod with a drill bit is inserted into the tail end of the catcher body, passes through the inner cavity of the catcher body, and exits through the inner hole of the drilling connection pipe to drill into the coal seam. An adjustable-length positioning rod is positioned between the tail end of the catcher body and the drill rod holder of the drilling rig. The positioning rod holds the catcher body in place, thus positioning the orifice catcher. A sealing sleeve is provided between the drill rod and the tail end of the capture device body. The drill rod rotates in the sealing sleeve. The inner cavity of the capture device body is provided with a water supply interface, a gas output interface, and a drill cuttings discharge interface in sequence from front to back. The water supply interface is connected to a water supply pipeline to spray water into the inner cavity for dust removal. The gas output interface is connected to an extraction manifold to extract and receive gas from the coal seam. The drill cuttings discharge interface is connected to a gas-water-slag separator to receive rock cuttings and coal cuttings drilled down. The method includes a preparation stage operation and a borehole gas drainage stage operation. The preparation phase operations are as follows: First, use a 120mm diameter drill bit to drill a hole in the rock layer to a depth of 2m. Insert the drill connection pipe at the front end of the capture device into the rock layer borehole and place the drill rig at the rear end of the capture device. Second, while inserting the drill rod with the drill bit into the catcher, place two adjustable-length positioning rods between the tail end of the catcher body and the drill rod holder of the drilling machine to hold the catcher in place. Third, connect the water supply interface, gas output interface and drill cuttings discharge interface of the orifice catcher to the water supply pipeline, the extraction manifold and the gas-water-slag separator respectively through pipelines. The drilling and gas removal stage operation is as follows: start the drilling rig and use compressed air to remove dust and drill into the rock strata and coal seam; after drilling into the coal seam, open the water supply interface to spray water into the internal cavity of the capture device to reduce dust, and at the same time start the extraction manifold to extract gas. The positioning top rod prevents the borehole catcher from being ejected from the borehole when the blowout is severe, allowing the drilling rig to drill and extract simultaneously during the coal penetration process.

2. The method for preventing blowouts in gas drainage boreholes according to claim 1, characterized in that, The positioning rod consists of two threaded rods, which are located on both sides of the drill rod of the drilling rig. Two adjusting nuts are provided on the drill rod holder of the drilling rig. The two threaded rods are screwed into the two adjusting nuts respectively. The positioning adjustment of the capture device body is achieved by rotating the adjusting nuts to adjust the length of the threaded rod extension.

3. The method for preventing blowouts in gas drainage boreholes according to claim 1, characterized in that, The gas-water-slag separator is equipped with a gas outlet, which is connected to an extraction manifold via a pipeline to discharge the gas flowing in with the coal slag into the extraction manifold.

4. The method for preventing blowouts in gas drainage boreholes according to claim 1, characterized in that, The gas-water-slag separator has an externally closed telescopic expansion device on the side wall opposite the receiving inlet for receiving rock cuttings and coal slag from the drill bit, which is used to automatically adjust the volume of the gas-water-slag separator chamber. A filter screen is inclinedly installed between the receiving inlet of the gas-water-slag separator and the bottom plate. A drain outlet is installed on the side of the bottom plate of the gas-water-slag separator. A slag discharge outlet is installed on the side wall of the gas-water-slag separator at the lower end of the inclined filter screen.

5. The method for preventing blowouts in gas drainage boreholes according to claim 4, characterized in that, The gas-water-slag separator is equipped with a float valve at the drain outlet and a control valve at the slag discharge outlet. When the water level reaches a certain height, the float valve opens to discharge the accumulated water, and the control valve opens periodically to clean the drilling slag.

6. The method for preventing blowouts in gas drainage boreholes according to claim 1, characterized in that, The sealing sleeve is a cast iron sealing sleeve, which is fitted into the tail end of the catcher body.

7. The method for preventing blowouts in gas drainage boreholes according to claim 1, characterized in that, The borehole diameter of the rock strata must be at least 120 mm, and the depth must be at least 2000 mm.

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