阅读说明：本技术 一种地层出少量天然气条件下的氮气抽吸作业方法 (Nitrogen pumping operation method under condition of low-volume natural gas formation ) 是由 邓柯 徐忠祥 周长虹 刘殿琛 唐贵 李宬晓 李刚 范黎明 董仕明 王虎 于 2019-10-16 设计创作，主要内容包括：本发明公开了一种地层出少量天然气条件下的氮气抽吸作业方法,属于钻井工程领域,包括以下步骤：a、氮气钻进作业时,关闭第一平板阀、第二平板阀、第一抽吸平板阀和第二抽吸平板阀；b、氮气增压后经高压注气管线进入钻机立管；c、氮气钻井期间进行起下钻作业时,向第一抽吸短接注入抽吸用氮气,向第二抽吸短接注入抽吸用氮气,使井口无天然气溢出；d、氮气钻井期间进行更换胶芯作业时,停止向钻机立管注入氮气,将天然气抽吸至井场外排砂管线的出口端燃烧排空。本发明通过向排砂管线内注入氮气,在井口位置产生抽吸力,将地层产出的天然气吸导至排砂管线内,避免天然气溢出井口,有效提升了起下钻、更换胶芯敞井作业的安全性。(The invention discloses a nitrogen pumping operation method under the condition of a small amount of natural gas produced from stratum, which belongs to the field of drilling engineering and comprises the following steps: a. when nitrogen drilling operation is carried out, the first flat plate valve, the second flat plate valve, the first suction flat valve and the second suction flat valve are closed; b. after nitrogen pressurization, the nitrogen enters a vertical pipe of the drilling machine through a high-pressure gas injection pipeline; c. when tripping operation is carried out during nitrogen drilling, nitrogen for suction is injected into the first suction short circuit, nitrogen for suction is injected into the second suction short circuit, and no natural gas overflows from a well mouth; d. and when the rubber core is replaced during nitrogen drilling, stopping injecting nitrogen into the vertical pipe of the drilling machine, pumping natural gas to the outlet end of the sand discharge pipeline outside the well site, and combusting and emptying. According to the invention, nitrogen is injected into the sand discharge pipeline, a suction force is generated at the position of the well mouth, and the natural gas produced by the stratum is sucked and guided into the sand discharge pipeline, so that the natural gas is prevented from overflowing the well mouth, and the safety of the open-hole operation of tripping and replacing the rubber core is effectively improved.)

1. A nitrogen pumping operation method under the condition of forming a small amount of natural gas comprises the following steps:

a. when a small amount of natural gas is formed and nitrogen drilling operation is carried out, a first flat plate valve (25), a second flat plate valve (26), a first suction flat valve (15) and a second suction flat valve (16) in a nitrogen suction system are closed, and a third flat plate valve (27), a fourth flat plate valve (28) and a fifth flat valve (29) are opened;

b. nitrogen produced by the first nitrogen producing unit (2) enters the low-pressure gate valve group (9) through a first low-pressure gas injection pipeline (20), nitrogen produced by the second nitrogen producing unit (3) enters the low-pressure gate valve group (9) through a second low-pressure gas injection pipeline (21), enters the booster set (10) through a low-pressure hose, and enters the drilling machine vertical pipe (1) through a high-pressure gas injection pipeline (19) after being boosted;

c. when a small amount of natural gas is formed and the tripping operation is carried out during nitrogen drilling, opening the first flat plate valve (25), the second flat plate valve (26), the first suction flat valve (15) and the second suction flat valve (16), and closing the third flat plate valve (27), the fourth flat plate valve (28) and the fifth flat valve (29); starting a first nitrogen production unit (2), injecting nitrogen gas for pumping into a first pumping short circuit (4), starting a second nitrogen production unit (3), and injecting nitrogen gas for pumping into a second pumping short circuit (5), so that no natural gas overflows from a well mouth;

d. when a small amount of natural gas is produced in the stratum, and rubber core replacement operation is carried out during nitrogen drilling, nitrogen injection into the drilling machine vertical pipe (1) is stopped, the nitrogen is emptied through the pressure relief pry body (11), the first flat plate valve (25), the second flat plate valve (26), the first suction flat valve (15) and the second suction flat valve (16) are opened, then the third flat plate valve (27), the fourth flat plate valve (28) and the fifth flat valve (29) are closed, and the natural gas in the shaft is sucked to the outlet end of the sand discharge pipeline (7) outside the well site and is emptied through combustion.

2. The method of claim 1, wherein the nitrogen pumping operation is performed under conditions of low natural gas formation: the nitrogen pumping system comprises a drilling machine vertical pipe (1), a first low-pressure gas injection pipeline (20), a second low-pressure gas injection pipeline (21), a first nitrogen production unit (2), a second nitrogen production unit (3), a first pumping short joint (4), a second pumping short joint (5), an in-well sand discharge pipeline (6), an out-well sand discharge pipeline (7), a well head blowout preventer group (8), a low-pressure gate valve group (9), a booster set (10), a pressure relief pry body (11) and a rotary control head (12) installed at the top of the well head blowout preventer group (8), wherein a hydraulic flat valve (13) is connected onto the rotary control head (12), the well head (13) is connected with the first pumping short joint (4), one end of the in-well sand discharge pipeline (6) is connected with the first pumping short joint (4), the other end of the well head is connected with the second pumping short joint (5), and the inlet end of the outer sand discharge pipeline (7) is connected with the second pumping short joint (5), an automatic igniter (14) is installed at the outlet end of a sand discharge pipeline (7) outside a well site, a first suction short circuit (4) is connected with a low-pressure gate valve group (9) through a first suction pipeline (34), a second suction short circuit (5) is connected with the low-pressure gate valve group (9) through a second suction pipeline (35), a first suction flat valve (15) is installed on the first suction short circuit (4), a second suction flat valve (16) is installed on the second suction short circuit (5), the low-pressure gate valve group (9) is connected with a booster set (10) through an air inlet low-pressure hose (17), the booster set (10) is connected with a pressure relief pry body (11), a vertical pipe flat valve (18) is connected on a vertical pipe (1) of the drilling machine, a high-pressure air injection pipeline (19) is connected on the vertical pipe flat valve (18), the high-pressure air injection pipeline (19) is connected with the pressure relief pry body (11), and the low-pressure gate valve group (9) is connected with a first nitrogen making unit (2) through a first, the low-pressure gate valve group (9) is connected with the second nitrogen-making unit (3) through a second low-pressure gas injection pipeline (21).

3. The method of claim 2, wherein the nitrogen pumping operation is performed under conditions of low natural gas formation: the low-pressure gate valve group (9) comprises a first pipeline (22), a second pipeline (23), a third pipeline (24), a first flat plate valve (25), a second flat plate valve (26), a third flat plate valve (27), a fourth flat plate valve (28) and a fifth flat plate valve (29), the first pipeline (22), the second pipeline (23) and the third pipeline (24) are sequentially connected end to end, a first air inlet port is formed in the first pipeline (22), a second air inlet port is formed in the second pipeline (23), the first flat plate valve (25) is installed on a first suction pipeline (34), the second flat plate valve (26) is installed on a second suction pipeline (35), the third flat plate valve (27) is installed on the third pipeline (24), the fourth flat plate valve (28) is installed on the first pipeline (22), and the fifth flat plate valve (29) is installed on the second pipeline (23).

4. A method of nitrogen pumping operations with low natural gas formation as claimed in claim 3, wherein: first system nitrogen unit (2) include eight air compressors (30) and two membrane nitrogen generator (31), connect four air compressors (30) on arbitrary membrane nitrogen generator (31), membrane nitrogen generator (31) are connected with the first inlet port on first pipeline (22) through first low pressure gas injection pipeline (20).

5. A method of nitrogen pumping operations with low natural gas formation as claimed in claim 3, wherein: the second nitrogen making unit (3) comprises four air compressors (30) and a membrane nitrogen making machine (31), the four air compressors (30) are respectively connected with the membrane nitrogen making machine (31), and the membrane nitrogen making machine (31) is connected with a second air inlet on the second pipeline (23) through a second low-pressure air injection pipeline (21).

6. The method of claim 2, wherein the nitrogen pumping operation is performed under conditions of low natural gas formation: the sand setting tank (32) is further included, and the sand setting tank (32) is connected with the outlet end of the sand discharge pipeline (7) outside the well site.

7. The method of claim 2, wherein the nitrogen pumping operation is performed under conditions of low natural gas formation: the first low-pressure gas injection pipeline (20) and the second low-pressure gas injection pipeline (21) are both hoses, the inner diameters of the first low-pressure gas injection pipeline (20) and the second low-pressure gas injection pipeline (21) are both 76.2mm, and the pressure grades are both 4 Mpa.

8. The method of claim 2, wherein the nitrogen pumping operation is performed under conditions of low natural gas formation: the high-pressure gas injection pipeline (19) is a steel pipeline, the inner diameter of the high-pressure gas injection pipeline (19) is 76.2mm, the pressure grade is 21Mpa, and a flowmeter (33) is installed on the high-pressure gas injection pipeline (19).

9. The method of claim 2, wherein the nitrogen pumping operation is performed under conditions of low natural gas formation: the inner diameter of the sand discharge pipeline (6) in the well site is 244.5mm, the pressure level is 7MPa, the inner diameter of the sand discharge pipeline (7) outside the well site is 254mm, and the pressure level is 4 MPa.

10. The method of claim 2, wherein the nitrogen pumping operation is performed under conditions of low natural gas formation: the nitrogen injection amount of the first suction short circuit (4) is 60m³Min, the nitrogen injection amount of the second suction short circuit (5) is 30m³/min。

Technical Field

The invention relates to the technical field of drilling engineering, in particular to a nitrogen pumping operation method under the condition of a small amount of natural gas produced from a stratum.

Background

The gas drilling technology has the advantages of accelerating, controlling leakage, protecting a reservoir and the like. The gas-containing layer section with poor drilling performance is accelerated more and more commonly by adopting gas drilling, once a small amount of natural gas is produced in the stratum encountered, the natural gas content is less than or equal to 10000m³And d, the circulating medium is converted into inert gas nitrogen to avoid underground explosion accidents, but the annular blowout preventer is usually lacked, the drilling tool is large in size and cannot rotate the control head assembly, and natural gas possibly overflows a wellhead to bring great potential safety hazards during open-hole operations such as tripping and replacing rubber cores.

At the present stage, no effective measure for solving the difficult problem that natural gas overflows a wellhead when open-hole operations such as tripping and replacing a rubber core are carried out under the condition that a small amount of natural gas is produced from the stratum exists, and the natural gas which possibly overflows is blown away by opening an upper anti-explosion exhaust fan and a lower anti-explosion exhaust fan of a drill floor to prevent the natural gas from gathering. This treatment method has many disadvantages, such as: the natural gas overflow device belongs to a passive control measure, cannot prevent the natural gas from overflowing from a wellhead fundamentally, and can only blow away the natural gas which possibly overflows through the exhaust fan; although the explosion-proof exhaust fan can blow away overflowed natural gas to avoid gathering, operators on a drill floor and a wellhead still need to directly face the overflowed natural gas, so that great potential safety hazards exist, particularly when knocking operation is carried out; because the safety of field operation cannot be ensured, when a small amount of natural gas is produced in a stratum to be met, the gas drilling operation is often forced to be stopped in advance, and the speed-up advantage is not brought into play.

Chinese patent publication No. CN 106014326a, published as 2016, 10, month, and 12, discloses a sand washing system for cleaning sand deposited on a blowout preventer of a nitrogen drilling wellhead, which is characterized in that: the nitrogen injection device and the water injection device are respectively connected to the gas-liquid mixing device, and the gas-liquid mixing device is connected to a wellhead rotation control head shell for nitrogen drilling through a flushing pipeline.

Although the sand washing system for cleaning the sand deposition of the blowout preventer of the nitrogen drilling wellhead disclosed by the patent document adopts the gas-liquid two-phase mixed fluid as the cleaning medium, the sand deposition in the cavity of the blowout preventer can be subjected to turbulent stirring and washing mode, so that the sand can be cleaned more easily and completely, and the oil sludge which is difficult to clean can be cleaned, the natural gas easily overflows from the wellhead during open-hole operations such as tripping and replacing rubber cores, so that the gas drilling open-hole operation has great potential safety hazard.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a nitrogen pumping operation method under the condition that a small amount of natural gas is produced from the stratum.

The invention is realized by the following technical scheme:

a nitrogen pumping operation method under the condition of forming a small amount of natural gas is characterized by comprising the following steps:

a. when a small amount of natural gas is produced from the stratum and nitrogen drilling operation is carried out, closing a first flat plate valve, a second flat plate valve, a first suction flat plate valve and a second suction flat plate valve in a nitrogen suction system, and opening a third flat plate valve, a fourth flat plate valve and a fifth flat plate valve;

b. nitrogen produced by the first nitrogen production unit enters a low-pressure gate valve group through a first low-pressure gas injection pipeline, nitrogen produced by the second nitrogen production unit enters a low-pressure gate valve group through a second low-pressure gas injection pipeline, enters a booster set through a low-pressure hose, and enters a drilling machine vertical pipe through a high-pressure gas injection pipeline after being boosted;

c. when a small amount of natural gas is produced in the stratum and the tripping operation is carried out during the nitrogen drilling, the first flat plate valve, the second flat plate valve, the first suction flat valve and the second suction flat valve are opened, and the third flat plate valve, the fourth flat plate valve and the fifth flat valve are closed; starting a first nitrogen making unit, injecting nitrogen for pumping into the first pumping short circuit, starting a second nitrogen making unit, and injecting nitrogen for pumping into the second pumping short circuit, so that no natural gas overflows from a well head;

d. when a small amount of natural gas is produced from the stratum, and rubber core replacement operation is carried out during nitrogen drilling, nitrogen injection into the drilling machine vertical pipe is stopped, the nitrogen is emptied through the pressure relief pry body, the first flat plate valve, the second flat plate valve, the first suction flat plate valve and the second suction flat plate valve are opened, the third flat plate valve, the fourth flat plate valve and the fifth flat plate valve are closed, and natural gas in the shaft is sucked to the outlet end of the sand discharge pipeline outside the well site and is emptied through combustion.

The nitrogen pumping system comprises a drilling machine vertical pipe, a first low-pressure gas injection pipeline, a second low-pressure gas injection pipeline, a first nitrogen production unit, a second nitrogen production unit, a first pumping short circuit, a second pumping short circuit, a sand discharge pipeline in a well field, an offsite sand discharge pipeline, a well mouth blowout preventer stack, a low-pressure gate valve group, a booster set, a pressure relief pry body and a rotary control head arranged at the top of the well mouth blowout preventer stack, wherein a hydraulic flat valve is connected to the rotary control head and connected with the first pumping short circuit, one end of the sand discharge pipeline in the well field is connected with the first pumping short circuit, the other end of the sand discharge pipeline in the well field is connected with the second pumping short circuit, the inlet end of the offsite sand discharge pipeline is connected with the second pumping short circuit, an automatic igniter is arranged at the outlet end of the sand discharge pipeline outside the well field, the first pumping short circuit is connected with the low-pressure gate valve group through the first pumping pipeline, install first suction flat valve on the first suction short circuit, install second suction flat valve on the second suction short circuit, low pressure brake valve group is connected with the pressure booster unit through the low pressure hose of admitting air, the pressure booster unit is connected with pressure release sled body, be connected with riser flat valve on the rig riser, be connected with high-pressure gas injection pipeline on the riser flat valve, high-pressure gas injection pipeline and pressure release sled body coupling, low pressure gate valve group is connected with first nitrogen unit through first low-pressure gas injection pipeline, low pressure gate valve group is connected with second nitrogen unit through second low-pressure gas injection pipeline.

The low-pressure gate valve group comprises a first pipeline, a second pipeline, a third pipeline, a first flat plate valve, a second flat plate valve, a third flat plate valve, a fourth flat plate valve and a fifth flat plate valve, wherein the first pipeline, the second pipeline and the third pipeline are sequentially connected end to end, a first air inlet port is formed in the first pipeline, a second air inlet port is formed in the second pipeline, the first flat plate valve is installed on a first suction pipeline, the second flat plate valve is installed on a second suction pipeline, the third flat plate valve is installed on the third pipeline, the fourth flat plate valve is installed on the first pipeline, and the fifth flat plate valve is installed on the second pipeline.

The first nitrogen making unit comprises eight air compressors and two membrane nitrogen making machines, wherein four air compressors are connected to any one membrane nitrogen making machine, and the membrane nitrogen making machine is connected with a first air inlet port on the first pipeline through a first low-pressure air injection pipeline.

The second nitrogen making unit comprises four air compressors and a membrane nitrogen making machine, the four air compressors are respectively connected with the membrane nitrogen making machine, and the membrane nitrogen making machine is connected with a second air inlet port on the second pipeline through a second low-pressure air injection pipeline.

The sand setting tank is connected with the outlet end of the sand discharge pipeline outside the well site.

The first low-pressure gas injection pipeline and the second low-pressure gas injection pipeline are both hoses, the inner diameters of the first low-pressure gas injection pipeline and the second low-pressure gas injection pipeline are both 76.2mm, and the pressure grades are both 4 Mpa.

The high-pressure gas injection pipeline is a steel pipeline, the inner diameter of the high-pressure gas injection pipeline is 76.2mm, the pressure level is 21Mpa, and a flowmeter is installed on the high-pressure gas injection pipeline.

The inner diameter of the sand discharge pipeline in the well site is 244.5mm, the pressure level is 7MPa, the inner diameter of the sand discharge pipeline outside the well site is 254mm, and the pressure level is 4 MPa.

The nitrogen injection amount of the first suction short circuit is 60m³Min, the nitrogen injection amount of the second suction short circuit is 30m³/min。

The basic principle of the invention is as follows:

the suction short circuit is additionally arranged at a specific position of the sand discharge pipeline, the two suction pipelines are connected to the suction short circuit from the nitrogen production unit, when open-hole operation of tripping and replacing rubber cores is carried out, nitrogen is injected into the sand discharge pipeline, and a certain suction force is formed at the position of a well mouth due to the fact that the injected nitrogen flows towards the direction of a discharge port in the sand discharge pipeline at a high speed, natural gas in a shaft is sucked and guided to the outlet of the sand discharge pipeline to be combusted and exhausted, so that the phenomenon that the natural gas in the shaft overflows from the well mouth during the open-hole operation is avoided, and the safety requirement of the open-hole operation of gas drilling under the condition that a small.

The beneficial effects of the invention are mainly shown in the following aspects:

1. in the invention, a, when a small amount of natural gas is discharged from a stratum and nitrogen gas is drilled, a first flat plate valve, a second flat plate valve, a first suction flat valve and a second suction flat valve in a nitrogen gas suction system are closed, and a third flat plate valve, a fourth flat plate valve and a fifth flat valve are opened; b. nitrogen produced by the first nitrogen production unit enters a low-pressure gate valve group through a first low-pressure gas injection pipeline, nitrogen produced by the second nitrogen production unit enters a low-pressure gate valve group through a second low-pressure gas injection pipeline, enters a booster set through a low-pressure hose, and enters a drilling machine vertical pipe through a high-pressure gas injection pipeline after being boosted; c. when a small amount of natural gas is produced in the stratum and the tripping operation is carried out during the nitrogen drilling, the first flat plate valve, the second flat plate valve, the first suction flat valve and the second suction flat valve are opened, and the third flat plate valve, the fourth flat plate valve and the fifth flat valve are closed; starting a first nitrogen making unit, injecting nitrogen for pumping into the first pumping short circuit, starting a second nitrogen making unit, and injecting nitrogen for pumping into the second pumping short circuit, so that no natural gas overflows from a well head; d. when a small amount of natural gas is produced in the stratum, when rubber core replacing operation is carried out during nitrogen drilling, nitrogen injection into a drilling machine vertical pipe is stopped, nitrogen is emptied through a pressure relief pry body, a first flat plate valve, a second flat plate valve, a first suction flat plate valve and a second suction flat plate valve are opened, then a third flat plate valve, a fourth flat plate valve and a fifth flat plate valve are closed, natural gas in a shaft is sucked to the outlet end of a sand discharge pipeline outside a well site and is emptied through combustion, as a complete technical scheme, compared with the prior art, a suction short joint is additionally arranged at a specific position of the sand discharge pipeline, two suction pipelines are connected to the suction short joint from a nitrogen production unit, and when open-hole operation of 'tripping and replacing rubber cores' is carried out, nitrogen is injected into the sand discharge pipeline, and a certain suction force is formed at the well head position due to the high-speed flow of the injected nitrogen in the sand discharge pipeline towards the direction, the natural gas of the shaft is sucked and guided to the outlet of the sand discharge pipeline for combustion and evacuation, so that the natural gas of the shaft is prevented from overflowing from the well mouth during open-hole operation, and the safety of the open-hole operation of tripping and replacing the rubber core is effectively improved.

2. The invention relates to a nitrogen pumping system, which comprises a drilling machine vertical pipe, a first low-pressure gas injection pipeline, a second low-pressure gas injection pipeline, a first nitrogen production unit, a second nitrogen production unit, a first pumping short joint, a second pumping short joint, a sand discharge pipeline in a well field, a sand discharge pipeline outside the well field, a well mouth blowout preventer stack, a low-pressure gate valve group, a booster set, a pressure relief pry body and a rotary control head arranged at the top of the well mouth blowout preventer stack, wherein a hydraulic flat valve is connected to the rotary control head and connected with the first pumping short joint, one end of the sand discharge pipeline in the well field is connected with the first pumping short joint, the other end of the sand discharge pipeline in the well field is connected with the second pumping short joint, the inlet end of the sand discharge pipeline outside the well field is connected with the second pumping short joint, the outlet end of the sand discharge pipeline outside the well field is provided with an automatic igniter, the first pumping short joint is connected with the low-pressure, the first suction short connector is provided with a first suction flat valve, the second suction short connector is provided with a second suction flat valve, the low-pressure gate valve group is connected with the booster set through an air inlet low-pressure hose, the booster set is connected with the pressure relief prying body, the drilling machine vertical pipe is connected with the vertical pipe flat valve, the vertical pipe flat valve is connected with a high-pressure air injection pipeline, the high-pressure air injection pipeline is connected with the pressure relief prying body, the low-pressure gate valve group is connected with the first nitrogen making unit through a first low-pressure air injection pipeline, the low-pressure gate valve group is connected with the second nitrogen making unit through a second low-pressure air injection pipeline, and the suction effect can be ensured by installing the two suction short connectors; the rotary control head is connected with a hydraulic flat valve, the hydraulic flat valve is connected with a first suction short circuit, one end of a sand discharge pipeline in a well field is connected with the first suction short circuit, the other end of the sand discharge pipeline is connected with a second suction short circuit, the inlet end of the sand discharge pipeline outside the well field is connected with the second suction short circuit, the specific positions of the first suction short circuit and the second suction short circuit are arranged, the suction force can be greatly improved, and the outlet end of the sand discharge pipeline outside the well field is ensured to be burnt and emptied by sucking and guiding natural gas in a shaft.

3. The invention adopts the structural design of a split type gas injection manifold, introduces the low-pressure gate valve group, and meets the requirements of nitrogen injection modes under different working conditions and the regulation and control of nitrogen injection amount at different suction short-circuit positions by switching the channels of the low-pressure gate valve group. Decomposing nitrogen making equipment into two nitrogen making units, connecting nitrogen produced by the two nitrogen making units in parallel to a low-pressure gate valve group, connecting one port of the low-pressure gate valve group with an air inlet low-pressure hose and feeding the inlet low-pressure hose into a booster set, and respectively connecting the other two ports of the low-pressure gate valve group with a first suction short circuit and a second suction short circuit through two suction pipelines; can provide the required nitrogen gas volume of nitrogen gas well drilling when switching low pressure floodgate valves passageway and realizing the well drilling according to different work condition, provide during the suction and inhale with required nitrogen gas volume, and can regulate and control the nitrogen gas volume of pouring into of first suction short circuit and second suction short circuit respectively, the flexible operation.

4. According to the invention, the automatic igniter is arranged at the outlet end of the well site external sand discharge pipeline, and during the nitrogen pumping operation, the natural gas pumped to the outlet end of the well site external sand discharge pipeline is ignited and combusted through the automatic igniter, so that safe and clean discharge is realized.

Drawings

The invention will be further described in detail with reference to the drawings and the detailed description, wherein:

FIG. 1 is a schematic block diagram of the wellhead operation of the nitrogen pumping system of the present invention;

FIG. 2 is a schematic structural diagram of a low-pressure gate valve set according to the present invention;

FIG. 3 is a schematic structural view of a first nitrogen-generating unit according to the present invention;

FIG. 4 is a schematic structural view of a second nitrogen-generating unit according to the present invention;

the labels in the figure are: 1. a drilling machine riser, 2, a first nitrogen production unit, 3, a second nitrogen production unit, 4, a first suction short joint, 5, a second suction short joint, 6, a sand discharge pipeline in a well field, 7, a sand discharge pipeline outside the well field, 8, a wellhead blowout preventer stack, 9, a low-pressure gate valve group, 10, a booster set, 11, a pressure relief pry body, 12, a rotary control head, 13, a hydraulic flat valve, 14, an automatic igniter, 15, a first suction flat valve, 16, a second suction flat valve, 17, an air inlet low-pressure hose, 18, a riser flat valve, 19, a high-pressure air injection pipeline, 20, a first low-pressure air injection pipeline, 21, a second low-pressure air injection pipeline, 22, a first pipeline, 23, a second pipeline, 24, a third pipeline, 25, a first flat valve, 26, a second flat valve, 27, a third flat valve, 28, a fourth flat valve, 29, a fifth flat valve, 30, an air compressor, 31 and a membrane nitrogen generator, 32. grit chamber, 33, flowmeter, 34, first suction line, 35, second suction line.

Detailed Description