A device for removing sand from a gas well

Abstract

The application discloses a kind of for gas well ground multistage separation sand removal device, it is related to the technical field of petroleum engineering natural gas exploitation migration technology guarantee, including base, with rear end production pipeline communication's intake pipe section, connect on intake pipe section multistage separation pipe section and bypass pipe, be arranged in multistage separation pipe section below and with it communication's sand storage pipe section, multistage separation pipe section and bypass pipe end and multistage separation pipe section end between connection have elbow pipe nipple, it is provided with flat gate valve three on the elbow pipe nipple, the front end of multistage separation pipe section is provided with flat gate valve two, and flat gate valve one is arranged on the intake pipe section between multistage separation pipe section and bypass pipe;The application adopts cyclone centrifugal section separation and slotted screen pipe section separation two-section type sand removal mode, separation mode is efficient, and separation efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of technology for ensuring the extraction and migration of natural gas in petroleum engineering, and more specifically to the field of technology for multi-stage separation and desanding devices on the surface of gas wells, used in mechanical oil production operations of oil and gas wells in high gas-liquid ratio reservoirs. Background Technology

[0002] The Qinghai gas field in the Qaidam Basin has unique geological conditions for development, mainly characterized by long gas-bearing well sections, numerous but thin gas layers, loose reservoir lithology, and weak edge water drive. Vertically, it features alternating sandstone and mudstone layers, gas-water layers, and high, medium, and low-yield layers, resulting in large differences between layers and easy sand production in the producing layers. This brings many difficulties to the efficient development of the gas field. In particular, sand production is common in high-pressure differential high-yield gas wells and water-producing gas wells. The sand and solid particles carried by natural gas cause significant damage to pipe walls, bends, valves, and other equipment when flowing in pipelines.

[0003] The flow velocity of the medium at the rear end of the throttle nozzle is close to or reaches the speed of sound, but the flow velocity upstream of the nozzle is relatively low. There is a large density difference between the gas-water mixture and the solid particles it contains. Therefore, the method of installing a "wellhead desanding device" in the transportation process is considered to solve this problem.

[0004] Even after passing through the wellhead desanding device, the pipeline still contains some sand. Currently, separators are generally installed at gas gathering stations to remove various solid (liquid) impurities carried in natural gas. Gravity separators and cyclone separators are widely used. For long-distance pipelines, the pipelines between stations are often tens of kilometers or even longer. During this period, solid impurities such as those carried by single-well pipelines and corrosion products generated by the pipeline itself are difficult to treat in a timely manner.

[0005] Chinese patent application number 201410815080.6 discloses a spiral desander, which includes a spiral separation tube, a short outlet section, a displacement sand storage tank, and a spiral separation tube mounting frame. The lower inlet of the spiral separation tube is connected to the bottom return fluid pipeline, and the upper outlet is connected to the surface water collection pipeline. Several blocking sand outlets are opened on the outer circumference of the spiral separation tube, and each sand outlet is connected to a closed displacement sand storage tank through a pipeline. The bottom of the displacement sand storage tank has a sand discharge port. The sand-containing return fluid from the bottom of the well enters from the lower inlet of the spiral separation tube and flows upward at high speed along the spiral separation tube. Under the action of centrifugal force, the sand particles in the return fluid are thrown to the outer circumference of the inner wall of the spiral separation tube and discharged into the displacement sand storage tank from the sand outlet. The spiral separation tube and the displacement sand storage tank are in a closed connection with pressure balance. With the help of centrifugal force, the sand particles are discharged into the displacement sand storage tank to displace the liquid. The liquid part is discharged from the upper outlet of the spiral separation tube into the surface water collection pipeline, thus realizing sand-liquid separation.

[0006] Chinese patent application number 96118733.6 discloses a crude oil wellhead pipe flow desander, which includes a spiral pipeline, a sand outlet at the end of the spiral pipeline, and a wedge at the junction of the pipeline and the sand outlet. It can remove sand directly from the pipeline by using the remaining energy of the oil well without the need for external driving force.

[0007] Chinese Patent Application No. 201810795010.7 discloses a full-bore pipeline sand remover, including an inlet tee, a full-bore pigging valve, a spiral sand removal section, a flow direction adjustment outlet, a bypass pipe, a full-bore ball valve, and a sand storage chamber. Spiral blades are arranged in the annular space between the outer cylinder and the inner cylinder of the cyclone sand removal section. A row of sand discharge ports is arranged at the bottom of the outer cylinder of the cyclone sand removal section below the spiral blades. The sand discharge ports serve as openings for solid and liquid impurities to enter the sand storage chamber.

[0008] The three existing patented technologies mentioned above all utilize the swirling flow field of the spiral tube to separate solid impurities. However, the existing structures are too rough, the forms are not reasonable enough, and the installation is too complicated. In particular, the sand separation section adopts the form of opening holes on the spiral tube. First of all, the number of openings in this method is greatly limited. Secondly, the position of the openings also has a great impact on the separation of sand, resulting in poor separation effect. Summary of the Invention

[0009] The purpose of this invention is to solve the above-mentioned technical problems by providing a multi-stage separation and sand removal device for gas wells, which can efficiently separate solid impurities in natural gas while utilizing the gas well's own energy for sand removal without affecting the normal production of the gas well.

[0010] To achieve the above objectives, the present invention specifically adopts the following technical solution:

[0011] A multi-stage separation and desanding device for gas wells includes a base, an intake pipe section connected to a downstream production pipeline, a multi-stage separation pipe section and a bypass pipe connected to the intake pipe section, and a sand storage pipe section located below and connected to the multi-stage separation pipe section. A bent pipe section is connected between the end of the multi-stage separation pipe section and the end of the bypass pipe section and the end of the multi-stage separation pipe section. A flat gate valve three is installed on the bent pipe section. A flat gate valve two is installed at the front end of the multi-stage separation pipe section. A flat gate valve one is installed on the intake pipe section between the multi-stage separation pipe section and the bypass pipe.

[0012] Furthermore, the multi-stage separation pipe section includes an outer sleeve connected to the air inlet pipe section, a reducing joint located at the front end of the outer sleeve, a swirl separation section, a venturi-like pipe section, and a slotted screen pipe section arranged sequentially and at intervals within the outer sleeve according to the airflow direction. The slotted screen pipe section extends out of the outer sleeve and a bent pipe section. A separation pipe connected to the sand storage pipe section is provided on the outer sleeve near the rear end of the venturi-like pipe section. A connecting pipe connected to the sand storage pipe section and used to balance the pressure between the two is provided on the outer sleeve at the slotted screen pipe section.

[0013] Furthermore, both the Venturi-like tube section and the slotted screen tube section are concentric with the outer sleeve.

[0014] Furthermore, the swirl separation section includes a central rod concentric with the outer sleeve, and spiral blades forming a swirl channel are disposed in the annular space between the outer sleeve and the central rod.

[0015] Furthermore, the multi-stage separation pipe section and bypass pipe are arranged in parallel, the connecting pipe and separation pipe are set vertically, and a base is also provided at the bottom to support the multi-stage separation pipe section, bypass pipe and sand storage pipe section, ensuring safe and stable operation.

[0016] Furthermore, a differential pressure gauge is installed on the outer sleeve corresponding to the slotted screen tube section to monitor the overall operating pressure and pressure relief pressure of the device.

[0017] Furthermore, the sand storage pipe section includes a sand storage pipe, reducing joints at the front and rear ends of the sand storage pipe, a purge valve on the front reducing joint, a sewage discharge line on the rear reducing joint, and a sewage discharge valve on the sewage discharge line. A support rod connected to the base is provided below the sand storage pipe.

[0018] Furthermore, a sampling port is provided on the sand storage pipe.

[0019] The beneficial effects of this invention are as follows:

[0020] 1. This invention employs a two-stage sand removal method: a cyclone centrifugal separation section and a slotted screen tube section. This method is highly efficient and efficient. Specifically, after the medium enters the equipment, it utilizes its own kinetic energy to enter the cyclone separation section, where forced cyclone separation generates strong rotational motion. The medium then passes through a Venturi-like tube, first contracting and accelerating, then expanding to expedite the separation of gas and sand. Since sand and other media in natural gas have different densities, under the combined action of centrifugal force, gravity, and fluid drag, the denser sand and water enter the sand storage section radially, removing larger solid impurities from the natural gas. The lighter natural gas and finer sand enter the rear section axially. The gas then enters the slotted screen tube section for secondary filtration, removing smaller solid impurities. Part of the gas enters the sand storage section and returns to the slotted tube section via a connecting pipe, achieving pressure balance by carrying sand into the sand storage tube. The separated sand particles then enter the sand storage section through the connecting pipe. When the amount of sand stored in the sand storage section reaches a certain level by checking the sampling port, the sand is discharged through the drain valve, and then the sand-free natural gas is discharged through the bypass pipe.

[0021] 2. The internal structure of this invention can be efficiently cleaned using pure gas, eliminating the risk of environmental pollution from natural gas leaks.

[0022] 3. The installation method of this invention is the same as that of ordinary valves, and the installation position can be designed according to different gas wellheads; it also takes into account both sand removal and pipeline cleaning conditions, making it convenient to use.

[0023] 4. This invention does not require well shut-in. Sand removal and cleaning operations can be performed by switching processes, without affecting the normal production of the gas well. Attached Figure Description

[0024] Figure 1 This is a schematic diagram (front view) of the present invention.

[0025] Figure 2 This is a schematic diagram (top view) of the structure of the present invention.

[0026] Figure 3 The diagram shows the installation process of this invention. The air inlet pipe is connected to point A, and the air outlet pipe is connected to point B.

[0027] Attached reference numerals: 1. Flat gate valve one, 2. Flat gate valve two, 3. Reducing joint, 4. Cyclone separator section, 5. Venturi-like tube, 6. Slotted screen tube, 7. Differential pressure gauge, 8. Bend short section, 9. Flat gate valve three, 10. Purge valve, 11. Reducing joint, 12. Sand storage pipe, 13. Connecting pipe, 14. Sampling port, 15. Drain valve, 16. Base, 17. Pipe support, 18. Bypass pipe. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0030] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] In the description of the embodiments of the present invention, it should be noted that the terms "inner", "outer", "upper", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0032] Example 1

[0033] like Figures 1 to 3 As shown, this embodiment provides a multi-stage separation and desanding device for gas wells, including a base 16, an air intake pipe section connected to a downstream production pipeline, a multi-stage separation pipe section and a bypass pipe 18 connected to the air intake pipe section, and a sand storage pipe section located below and connected to the multi-stage separation pipe section. A bent pipe section 8 is connected between the end of the multi-stage separation pipe section and the end of the bypass pipe 18 and the end of the multi-stage separation pipe section. A flat gate valve 9 is provided on the bent pipe section 8. A flat gate valve 2 is provided at the front end of the multi-stage separation pipe section. A flat gate valve 1 is provided on the air intake pipe section between the multi-stage separation pipe section and the bypass pipe 18.

[0034] The multi-stage separation pipe section includes an outer sleeve connected to the air inlet pipe section, a reducing joint 3 located at the front end of the outer sleeve, a swirl separation section 4 arranged sequentially and at intervals in the airflow direction within the outer sleeve, a venturi-like pipe section 5, and a slotted screen pipe section 6. The slotted screen pipe section 6 extends from the outer sleeve and a bent pipe section 8. A separation pipe connected to the sand storage pipe section is provided on the outer sleeve near the rear end of the venturi-like pipe section 5. A connecting pipe 13 connected to the sand storage pipe section and used to balance the pressure between the two is provided on the outer sleeve at the slotted screen pipe section 6.

[0035] Both the Venturi-like tube section 5 and the slotted screen tube section 6 are concentric with the outer sleeve.

[0036] The swirl separation section 4 includes a central rod concentric with the outer sleeve, and spiral blades forming a swirl channel are arranged in the annular space between the outer sleeve and the central rod.

[0037] The multi-stage separation pipe section and bypass pipe 18 are arranged in parallel, and the connecting pipe 13 and separation pipe are set vertically. A base 16 is also provided at the bottom to support the multi-stage separation pipe section, bypass pipe 18 and sand storage pipe section, ensuring safe and stable operation.

[0038] A differential pressure gauge 7 is installed on the outer sleeve corresponding to the slotted screen tube section 6 to monitor the overall operating pressure and pressure relief pressure of the device.

[0039] In this embodiment, the cyclone separation section's sand-discharging outlet is the same as that of a Venturi-like tube, and the cyclone separation section and the Venturi-like tube are arranged coaxially. The Venturi-like tube first contracts and accelerates, then expands, accelerating the separation of gas and sand. The Venturi-like tube outlet is connected to the separation pipe. They are arranged vertically, with the sand discharge port serving as the opening for solid and liquid impurities to enter the sand storage section. Due to the different densities of sand and other media in natural gas, under the combined action of centrifugal force, gravity, and fluid drag, the denser sand and water enter the sand storage section radially, removing solid impurities from the natural gas, while the lighter natural gas and fine sand enter the rear end axially.

[0040] The slotted screen section and the outer casing are nested, with the two arranged concentrically. The slotted screen section is welded and fixed inside the outer casing. Gas enters the slotted screen section for secondary filtration and separation to remove solid impurities from the natural gas. A portion of the gas enters the sand storage section and then returns to the slotted screen section via a connecting pipe, achieving pressure equilibrium by carrying sand and gravel into the sand storage section. The separated sand particles then enter the sand storage section through the connecting pipe.

[0041] Example 2

[0042] This embodiment is an optimization based on Embodiment 1, specifically:

[0043] The sand storage pipe section includes a sand storage pipe 12, reducing joints 11 at the front and rear ends of the sand storage pipe 12, a purge valve 10 on the front reducing joint 11, a sewage discharge line on the rear reducing joint 11, and a sewage discharge valve 15 on the sewage discharge line. A support rod connected to a base 16 is provided below the sand storage pipe 12.

[0044] The sand storage pipe 12 is equipped with a sampling port 14.

[0045] Work process:

[0046] Sand removal steps: such as Figure 2As described, natural gas from the wellhead enters the device from point A, passes through the flat gate valve 2 into the cyclone separation section 4, generating strong rotational motion. It then passes through a Venturi-like tube 5, first contracting and accelerating, then expanding to expedite the separation of gas and gravel. Due to the different densities of sand and other media in the natural gas, under the combined action of centrifugal force, gravity, and fluid drag, the denser sand and water enter the sand storage pipe 12 radially, removing larger sand particles from the natural gas. The lighter natural gas and finer sand enter the slotted screen section 6 axially for secondary filtration, removing smaller sand particles. Some gas enters the sand storage pipe 12 and returns to the slotted screen section 6 via the connecting pipe 13, achieving pressure balance by carrying gravel into the sand storage pipe 12. The separated sand particles then enter the sand storage pipe 12 uniformly through the connecting pipe 13. The amount of sand stored in the sand storage pipe is monitored by checking the sand collection at the sampling port 14, and sand removal is performed periodically.

[0047] Sand removal steps: Open plate gate valve 1, close plate gate valve 2 and plate gate valve 3, open differential pressure gauge 7 pressure relief valve to release pressure, wait for the pressure to return to zero, open drain valve 15, introduce high-pressure water or nitrogen through purge valve 10 to clean or purge the accumulated sand in sand storage pipe 12, drain valve 15 removes sand and gravel, open purge port valve 10, introduce nitrogen through differential pressure gauge 7 pressure relief valve for replacement and pressure test (6.4MPa), install differential pressure gauge 7, open desander plate gate valve 2 and plate gate valve 3, close plate gate valve 1, and resume normal sand output production.

Claims

1. A multi-stage separation and desanding device for gas well surface, comprising a base (16), characterized in that, An air intake pipe section connected to the downstream production pipeline, a multi-stage separation pipe section and a bypass pipe (18) connected to the air intake pipe section, and a sand storage pipe section located below and connected to the multi-stage separation pipe section. A bent pipe section (8) is connected between the end of the multi-stage separation pipe section and the end of the multi-stage separation pipe section. A flat gate valve three (9) is installed on the bent pipe section (8). A flat gate valve two (2) is installed at the front end of the multi-stage separation pipe section. A flat gate valve one (1) is installed on the air intake pipe section between the multi-stage separation pipe section and the bypass pipe (18). The multi-stage separation pipe section includes an outer sleeve connected to the inlet pipe section, a reducing joint (3) located at the front end of the outer sleeve, a swirl separation section (4) arranged sequentially and at intervals in the outer sleeve according to the airflow direction, a venturi-like pipe section (5), and a slotted screen pipe section (6). The slotted screen pipe section (6) extends out of the outer sleeve and a bent pipe section (8). A separation pipe connected to the sand storage pipe section is provided on the outer sleeve near the rear end of the venturi-like pipe section (5). A connecting pipe (13) connected to the sand storage pipe section and used to balance the pressure between the two is provided on the outer sleeve at the slotted screen pipe section (6). The venturi-like pipe section (5) and the slotted screen pipe section (6) are both concentric with the outer sleeve. The swirl separation section (4) includes a central rod concentric with the outer sleeve. Spiral blades forming a swirl channel are provided in the annular space between the outer sleeve and the central rod. A differential pressure gauge (7) is installed on the outer sleeve corresponding to the slotted screen pipe section (6). The cyclone separation section (4) and the slotted screen section (6) are arranged horizontally.

2. The multi-stage separation and desanding device for gas wells as described in claim 1, characterized in that, The multi-stage separation pipe section and bypass pipe (18) are arranged in parallel, the connecting pipe (13) and the separation pipe are set vertically, and a base (16) is also provided at the bottom to support the multi-stage separation pipe section, bypass pipe (18) and sand storage pipe section.

3. A multi-stage separation and desanding device for gas wells on the surface according to claim 1, characterized in that, The sand storage pipe section includes a sand storage pipe (12), a reducing joint (11) set at the front end and the rear end of the sand storage pipe (12), a purge valve (10) set on the front reducing joint (11), a sewage pipeline set on the rear reducing joint (11), and a sewage valve (15) set on the sewage pipeline. A support rod connected to the base (16) is set below the sand storage pipe (12).

4. A multi-stage separation and desanding device for gas wells on the surface according to claim 3, characterized in that, The sand storage pipe (12) is equipped with a sampling port (14).

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