Natural gas hydrate multi-inlet tangential rotational flow in-situ sand removing tool

Abstract

The invention relates to a natural gas hydrate multi-inlet tangential rotational flow in-situ sand removing tool which comprises a hydrate tangential inlet device, a mud and sand rotational flow separation device, a tubular sand discharging device and a tubular separation shell, the hydrate tangential inlet is formed in the top end of the tubular separation shell, and a hydrate circumferential suction inlet is formed in the tubular separation shell; the mud and sand cyclone separation device and the tubular sand discharging device are sequentially arranged in the tubular separation shell from top to bottom, the mud and sand cyclone separation device comprises a cyclone generation platform and a crushing spiral device, and the crushing spiral device is arranged below the cyclone generation platform. According to the invention, in-situ separation and in-situ backfilling of mud and sand are carried out on the seabed natural gas hydrate by utilizing a hydraulic cyclone principle, and the designed device is an in-situ desilting-backfilling module in a tool pipe string matched with hydrate exploitation.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum and natural gas hydrate development, in particular to a natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool. Background Art

[0002] The weakly cemented mixed slurry formed by the solid fluidization mining method of natural gas hydrate (NGH), which is composed of natural gas hydrate, sediment and water, has the characteristics of shallow burial depth, weak cementation, instability and high sand content. The huge reserves of natural gas hydrate and its cleanliness make it increasingly attractive and is expected to become a promising new energy source. Offshore natural gas hydrate resources are a huge source of natural gas. Due to the large amount of sand produced, the continuous production capacity of hydrates is poor, the recovery rate is low, and the equipment is blocked and worn. The hydrate separation and sand removal and sand control technology has become a technical bottleneck in the process of commercial mining. Directly using conventional solid-liquid cyclone structure for underground sand removal cannot achieve good separation effect.

[0003] The current problems faced by hydrate mining are: (1) Large blocks of mud and sand mixed solids may exist during hydrate extraction, and the existing separation device does not consider the secondary crushing of hydrates; (2) The existing seabed hydrate desanding equipment has a complex structure, and has a low fault tolerance and poor reliability during the deep-sea hydrate separation operation; (3) In the actual mining process, after the drill bit or jet breaks the hydrate layer, there are often large pieces of hydrate mud and sand mixture, which can easily block the flow channel.

[0004] Therefore, there is an urgent need for a natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool. Summary of the invention

[0005] The present invention provides a natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool to achieve in-situ real-time separation and backfilling of high-sand mixed fluids in the well during conventional hydrate recovery.

[0006] The present invention provides a natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool, comprising a hydrate tangential inlet device, a mud and sand cyclone separation device, a tubular sand discharge device and a tubular separation shell, wherein the hydrate inlet is arranged at the top of the tubular separation shell, the tubular separation shell is provided with a hydrate circumferential suction port, the mud and sand cyclone separation device and the tubular sand discharge device are arranged in sequence from top to bottom in the tubular separation shell, the mud and sand cyclone separation device comprises a cyclone generating platform and a crushing spiral device, and the crushing spiral device is arranged below the cyclone generating platform.

[0007] The natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool, preferably, the hydrate tangential inlet device includes a tangential separation inlet channel, a drilling fluid oil pipe and an overflow recovery channel, the tangential separation inlet channel is arranged on the outside of the tubular separation shell, the tangential separation inlet channel is circumferentially provided with a rectangular hydrate circumferential suction port, the drilling fluid oil pipe is arranged on the inside of the tubular separation shell, one end of the drilling fluid oil pipe is connected to the tangential separation inlet channel, and the overflow recovery channel is provided on the outside of the drilling fluid oil pipe, and the other end of the drilling fluid oil pipe is connected to the mud and sand cyclone separation device.

[0008] The natural gas hydrate multi-inlet tangential vortex in-situ sand removal tool, preferably, the crushing spiral device includes a central fixed pipe, spiral blades, a drilling fluid channel and a power fluid channel, the central fixed pipe is connected to the drilling fluid oil pipe, the power fluid channel is arranged inside the central fixed pipe and is coaxial, the drilling fluid channel is arranged on the outside of the power fluid channel, the top of the drilling fluid channel is connected to the vortex generating platform, and the outer wall of the drilling fluid channel is provided with the spiral blades.

[0009] The natural gas hydrate multi-inlet tangential vortex in-situ sand removal tool is preferably provided with an upper fixing clamp, a connecting block, a lower fixing clamp and a spiral fixing sealing plate on the drilling fluid channel; the drilling fluid channel is connected to the vortex generating platform via the connecting block and the upper fixing clamp; the lower fixing clamp is arranged at the bottom of the drilling fluid channel; and the spiral fixing sealing plate is arranged at the bottom of the drilling fluid channel via the lower fixing clamp.

[0010] The natural gas hydrate multi-inlet tangential swirl in-situ sand removal tool, preferably, the tubular sand removal device includes a tubular in-situ mud and sand collection chamber, a tubular sand removal valve and a sand removal pressure-bearing base, the sand removal pressure-bearing base is connected to the tubular separation shell, the tubular in-situ mud and sand collection chamber is provided on the sand removal pressure-bearing base, and the tubular in-situ mud and sand collection chamber is provided on the tubular in-situ mud and sand collection chamber.

[0011] In the natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool, preferably, the cyclone generating platform is a disc structure, and the size of the cyclone generating platform is smaller than the tubular separation shell.

[0012] The beneficial effects are: The invention is provided with a crushing spiral device to realize secondary crushing of large blocks of mud and sand mixed solids.

[0013] The invention is suitable for solid fluidized mining technology, has no complicated mechanical structure, realizes the integration of hydraulic drive and crushing reamer, is suitable for the harsh environment of deep sea, and the separation method is simple and reliable. The spiral-cyclone coupling principle is used to break the "weak cementation bonds" between the solid hydrate particles and the mud and sand particles, thereby achieving hydrate debonding and separation of cross-scale micron-sized particles in the natural gas hydrate mixed slurry, so as to improve the cleanliness of the returned hydrate slurry and achieve the effect of increasing production capacity.

[0014] The present invention utilizes spiral blades for secondary crushing, and discharges mud and sand in situ after sand removal, thereby reducing the vertical pipe conveying volume, reducing the erosion, wear and blockage of the wellbore, equipment, etc. by mud and sand, and timely backfilling the mud and sand separated in situ can prevent the dynamic balance of the hydrate reservoir from being disrupted, and can also prevent collapse accidents during oil production. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2-1 is a schematic diagram of a crushing spiral device of the present invention; Figure 2-2 It is a cross-sectional view in the B-B' direction; Figure 3-1 It is a schematic diagram of the overflow recovery channel of the present invention; Figure 3-2 It is a cross-sectional view along the A-A direction.

[0016] 1. Sand discharge pressure bearing base; 2. Tube type sand discharge valve; 3. Crushing spiral device; 301. Drilling fluid channel; 302. Spiral blades; 303. Power fluid channel; 305, central fixing tube; 306, upper fixing clamp; 307, lower fixing clamp; 308, spirally fixed sealing plate; 309, connecting block; 4. Tubular separation housing; 401. Hydrate circumferential suction port; 5. Overflow recovery channel; 6. Tangential separation inlet channel; 7. Drilling fluid oil pipe; 8. Cyclone generating platform; 9. Tubular in-situ mud and sand collection chamber. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] In the description of the present invention, it should be noted that the terms "upper" and "lower" etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0019] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] The present invention provides a natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool, characterized in that it includes a hydrate tangential inlet device, a mud and sand cyclone separation device, a tubular sand discharge device and a tubular separation shell, wherein the hydrate inlet is arranged at the top of the tubular separation shell, the tubular separation shell is provided with a hydrate circumferential suction port, the mud and sand cyclone separation device and the tubular sand discharge device are arranged in the tubular separation shell from top to bottom in sequence, and the mud and sand cyclone separation device includes a cyclone generating platform and a crushing spiral device, and the crushing spiral device is arranged below the cyclone generating platform. . The present invention adopts the spiral-cyclone coupling principle to break the "weak bonding bond" between hydrate solid particles and mud and sand particles, thereby achieving the debonding of hydrates, and can realize the separation of cross-scale micron-level particles of natural gas hydrate mixed slurry, so as to improve the cleanliness of the returned hydrate slurry and achieve the effect of increasing production capacity.

[0021] The entire technical process is described in detail below using a natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool as an example.

[0022] like Figure 1 As shown, a natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool includes a hydrate tangential inlet device, a mud and sand cyclone separation device, a tubular sand discharge device and a tubular separation shell 4, wherein the hydrate inlet is arranged at the top of the tubular separation shell, the tubular separation shell is provided with a hydrate circumferential suction port, the mud and sand cyclone separation device and the tubular sand discharge device are arranged in the tubular separation shell from top to bottom, the mud and sand cyclone separation device includes a cyclone generation platform and a crushing spiral device, and the crushing spiral device is arranged below the cyclone generation platform. Among them, the cyclone generation platform 9 is a disc structure, and the size of the cyclone generation platform 8 is smaller than the tubular separation shell 4.

[0023] like Figure 3-1 , Figure 3-2 As shown, a hydrate circumferential suction port 401 is provided on the tubular separation shell 4.

[0024] Among them, the tubular sand discharge device includes a tubular in-situ mud and sand collection chamber 9, a tubular sand discharge valve 2 and a sand discharge pressure-bearing base 1. The sand discharge pressure-bearing base 1 is connected to the tubular separation shell 4. The sand discharge pressure-bearing base 1 is provided with a tubular in-situ mud and sand collection chamber 9, and the tubular in-situ mud and sand collection chamber 9 is provided with a tubular sand discharge valve 2.

[0025] The function of the tubular sand discharge valve 2 is to open the valve of the tubular sand discharge valve 2 to discharge the mud and sand when the sand discharge pressure bearing base 1 is overloaded by the pressure of mud and sand accumulation in the tubular mud and sand in-situ collection chamber 9.

[0026] The hydrate tangential inlet device includes a tangential separation inlet channel 6, a drilling fluid oil pipe 7 and an overflow recovery channel 5. The separation inlet channel 6 is arranged outside the tubular separation shell 4. The tangential separation inlet channel 6 is circumferentially provided with a rectangular hydrate circumferential suction port. The drilling fluid oil pipe 7 is arranged inside the tubular separation shell. One end of the drilling fluid oil pipe 7 is connected to the tangential separation inlet channel 6, and the upper end of the drilling fluid oil pipe 7 connected to the tangential separation inlet channel is provided with an overflow recovery channel 5. The upper end of the overflow recovery channel 5 is also connected to the conveying pipeline, and the separated produced fluid is conveyed to the offshore platform through the conveying pipeline. The overflow recovery channel 5 is a channel for the natural gas hydrate after sand removal to return from the upper part of the separator. The lower end of the drilling fluid oil pipe 7 is connected to the mud and sand cyclone separation device in turn.

[0027] like Figure 2-1 and Figure 2-2 As shown, the crushing spiral device 3 includes a central fixed pipe 305, spiral blades 302, a drilling fluid channel 301 and a power fluid channel 303. The central fixed pipe 305 is connected to the drilling fluid oil pipe 7. The central fixed pipe 305 is used to position and fix the power fluid channel 303. The power fluid channel 303 is arranged inside the central fixed pipe 305 and is coaxial. The outer side of the power fluid channel 303 is provided with a drilling fluid channel 301. The upper part of the drilling fluid channel 301 is connected to the cyclone generating platform 8. The outer wall of the drilling fluid channel 301 is provided with spiral blades 302, so that the power fluid provides the mud and sand cyclone separation device with rotational power after passing through the power fluid channel, and the separated produced fluid is discharged from the drilling fluid channel. .

[0028] The drilling fluid channel 301 is also provided with an upper fixing clamp 306, a connecting block 309, a lower fixing clamp 307 and a spiral fixing sealing plate 308. The drilling fluid channel 301 is connected to the swirl generating platform 8 through the connecting block 309 and the upper fixing clamp 306 to limit the installation position and ensure the central symmetry of the installation. The lower fixing clamp 307 is arranged at the bottom of the drilling fluid channel 301, and the spiral fixing sealing plate 308 is arranged at the bottom of the drilling fluid channel 301 through the lower fixing clamp 307.

[0029] Power fluid driven crushing screw device process: The power fluid is injected from the upper tangential separation inlet channel 6 and the annulus of the swirl generating platform 8. The swirl generating platform 8 is a disc, which is smaller than the tubular separation housing 4. The power fluid passes through the drilling fluid oil pipe 7, the central fixed pipe 305 and the power fluid channel 303, and enters the crushing spiral device 3 to drive the spiral blades 302, and further drives the crushing spiral device 3 to rotate to crush the block mud or hydrate. The power fluid continues to flow downward, flows through the tubular in-situ mud and sand collection chamber 9, the tubular sand discharge valve 2, and the sand discharge pressure base 1 in sequence, and finally flows out of the natural gas hydrate multi-inlet tangential swirl in-situ sand removal tool.

[0030] Gas hydrate separation process: The natural gas hydrate mud-sand mixed liquid (hereinafter referred to as produced liquid) enters from the hydrate circumferential suction port 401 and enters the tubular separation housing 4. The produced liquid is crushed by the crushing spiral device 3, and the large pieces of mud and sand are crushed into fine particles. Due to the centrifugal force, the crushing spiral device 3 also plays a role in breaking the cementation of natural gas hydrate. Since the density of the separated mud and sand is greater than the density of the separated produced liquid, and under the spiral rotation centrifugal action of the crushing spiral device 3, the produced liquid after crushing by the crushing spiral device 3, the separated mud and sand pass through the tubular in-situ mud and sand collection chamber 9 and are directly discharged into the sea. The separated produced liquid continues to flow upward, enters the vortex generating platform 8, and passes upward through the overflow recovery channel 5, and is finally transported to the marine platform.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool, characterized in that: It includes a hydrate tangential inlet device, a mud and sand cyclone separation device, a tubular sand discharge device and a tubular separation shell, the hydrate inlet is arranged at the top of the tubular separation shell, the tubular separation shell is provided with a hydrate circumferential suction port, the mud and sand cyclone separation device and the tubular sand discharge device are arranged in the tubular separation shell from top to bottom in sequence, the mud and sand cyclone separation device includes a cyclone generating platform and a crushing spiral device, and the crushing spiral device is arranged below the cyclone generating platform.

2. The natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool according to claim 1, characterized in that: The hydrate tangential inlet device includes a tangential separation inlet channel, a drilling fluid oil pipe and an overflow recovery channel. The tangential separation inlet channel is arranged outside the tubular separation shell, and a rectangular hydrate circumferential suction port is circumferentially provided on the tangential separation inlet channel. The drilling fluid oil pipe is arranged inside the tubular separation shell, one end of the drilling fluid oil pipe is connected to the tangential separation inlet channel, and the overflow recovery channel is provided outside the drilling fluid oil pipe, and the other end of the drilling fluid oil pipe is connected to the mud and sand cyclone separation device.

3. The natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool according to claim 2, characterized in that: The crushing spiral device includes a central fixed pipe, spiral blades, a drilling fluid channel and a power fluid channel. The central fixed pipe is connected to the drilling fluid oil pipe. The power fluid channel is arranged inside the central fixed pipe and is coaxial. The drilling fluid channel is arranged on the outside of the power fluid channel. The top of the drilling fluid channel is connected to the vortex generating platform, and the spiral blades are arranged on the outer wall of the drilling fluid channel.

4. The natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool according to claim 3, characterized in that: The drilling fluid channel is also provided with an upper fixing clamp, a connecting block, a lower fixing clamp and a spiral fixing sealing plate. The drilling fluid channel is connected to the swirl generating platform through the connecting block and the upper fixing clamp. The lower fixing clamp is arranged at the bottom of the drilling fluid channel. The spiral fixing sealing plate is arranged at the bottom of the drilling fluid channel through the lower fixing clamp.

5. The natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool according to claim 4, characterized in that: The tubular sand discharge device comprises a tubular in-situ mud and sand collection chamber, a tubular sand discharge valve and a sand discharge pressure-bearing base, the sand discharge pressure-bearing base is connected to the tubular separation shell, the tubular in-situ mud and sand collection chamber is arranged on the sand discharge pressure-bearing base, and the tubular in-situ mud and sand collection chamber is provided with the tubular sand discharge valve.

6. The natural gas hydrate multi-inlet tangential cyclone in-situ sand removal tool according to any one of claims 1 to 5, characterized in that: The swirl flow generating platform is a disc structure, and the size of the swirl flow generating platform is smaller than the tubular separation shell.

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