Method for determining critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions

Abstract

The application relates to the field of hydrate flow assurance in a deepwater gas well, in particular to a method and device for judging the critical deposition of hydrate particles under the condition of high gas-liquid ratio vertical pipe flow. The device for judging the critical deposition of hydrate particles under the condition of high gas-liquid ratio vertical pipe flow is suitable for hydrate particles in contact with the inner wall of a pipe, and the device comprises a judging module for judging whether the hydrate particles are in force balance; if yes, the hydrate particles can be stably deposited on the inner wall of the pipe; if no, the hydrate particles cannot be stably deposited on the inner wall of the pipe. The judgment basis of the hydrate particle deposition state in the application is the force condition of the particles, and when the fluid flow parameters in the pipe string are known, the particle deposition state can be conveniently judged, the deposition state of the hydrate particles is mainly judged for annular flow and mist flow in the pipe string, the theoretical help is provided for solving the hydrate flow obstacle problem, the device is suitable for various high gas-liquid ratio flow working conditions, and is widely used in the field.

Description

Technical Field

[0001] This application relates to the field of hydrate flow assurance in deep water gas wells, specifically to a method for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions and a device for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions. Background Technology

[0002] The elucidation of the deposition mechanism of hydrate particles is crucial for solving the problem of hydrate flow assurance, particularly in the field of energy development, such as the deposition and blockage of hydrates in wellbores during the development of deep-water gas reservoirs, and the problem of secondary hydrate formation in wellbores during the development of hydrate reservoirs.

[0003] Due to the harsh operating conditions and fluctuating fluid temperature and pressure in deepwater resource development, the wellbore tubing often meets the conditions for hydrate formation. The tubing diameter reduction caused by hydrate formation and deposition obstructs wellbore flow, creating a hydrate flow barrier. Currently, hydrate flow barriers have become one of the most serious flow assurance problems in deepwater resource development, significantly impacting the process: hydrate formation and tubing wall deposition narrow fluid flow channels, increase pressure drop along the wellbore, affect the accuracy of test results, and render the tests meaningless; hydrate removal undoubtedly increases costs, leading to test termination and extended testing time; when hydrate deposition is rapid and detected late, complete tubing blockage can easily occur, creating pressure buildup within the tubing, inducing formation leakage or tubing rupture, significantly increasing development costs, and even causing construction failure. Therefore, the prevention and control of hydrate flow barriers are crucial issues in risk management during deepwater resource development.

[0004] Existing research lacks a clear understanding of the formation mechanisms of hydrate flow barriers under different flow patterns within a tubing, particularly under high gas-liquid ratio conditions. Annular and mist flows with high gas-liquid ratios are extremely common flow patterns in production processes; however, in the study of hydrate flow barriers, existing research uses "annular mist flow" instead of the concept of annular flow, neglecting the mist flow pattern. Furthermore, the deposition dynamics of hydrates are determined by the stress conditions of hydrate particles and the deposition layer. Based on the principle of mechanical equilibrium, the mechanisms of hydrate deposition and flow barrier formation under high gas-liquid ratio annular / mist flow patterns within a tubing under multiple forces and factors need further clarification. Summary of the Invention

[0005] The purpose of this application is to provide a method and apparatus for determining the critical deposition conditions of hydrate particles under high gas-liquid ratio vertical pipe flow conditions, used to determine the deposition conditions of hydrate particles under annular and mist-like flow patterns with high gas-liquid ratios. This invention can provide theoretical support for solving the problem of hydrate flow obstruction within a pipe column.

[0006] To achieve the above objectives, the first aspect of this application provides a method for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions, characterized in that it is applicable to hydrate particles in contact with the inner wall of the pipe, and the method includes: determining whether the hydrate particles are in force balance.

[0007] If so, the hydrate particles can be stably deposited on the inner wall of the pipe; if not, the hydrate particles cannot be stably deposited on the inner wall of the pipe.

[0008] Based on the first aspect, in some embodiments of the present invention, determining whether the hydrate particles are in force balance includes: if the hydrate particles are in force balance, the following balance conditions must be met: 1) force balance in the horizontal direction; 2) force balance in the vertical direction; 3) total torque balance.

[0009] Based on the first aspect, in some embodiments of the present invention, the method further includes: classifying the contact mode between the hydrate particles and the inner wall of the pipe, specifically including the following three categories: 1) when the hydrate particles are completely in the gas phase and in contact with the inner wall of the pipe, it is direct contact; 2) when the hydrate particles are completely in the liquid phase and in contact with the inner wall of the pipe, it is immersion contact; 3) when the hydrate particles are partially immersed in the liquid phase, and the part immersed in the liquid phase is in contact with the inner wall of the pipe, while the remaining part is in the gas phase, it is semi-immersion contact.

[0010] Based on the first aspect, in some embodiments of the present invention, if the hydrate particles are in equilibrium under forces in the horizontal direction, without considering other horizontal force components acting on the hydrate particles, the hydrate particles must satisfy the following force condition: F S ≤F J In the formula F S F represents the Saffman lift force experienced by the hydrate particles. J This indicates the adhesion force between hydrate particles and the pipe wall.

[0011] Based on the first aspect, in some embodiments of the present invention, the Saffman lift force F experienced by the hydrate particles S The Saffman lift force F acting on hydrate particles fully immersed in the liquid phase is obtained from the following formula: S for: In the formula, r h ρ represents the radius of the hydrate particle. l The density of the liquid phase, μ l The viscosity of the liquid phase, v w Let v represent the flow velocity of the liquid phase, v represent the velocity of the hydrate particles, and y represent the distance from a point in the liquid film to the pipe wall; calculate the Saffman lift force F experienced by the hydrate particles partially immersed in the liquid phase. SIn this case, only the portion immersed in the liquid phase is considered. Assuming the volume of the hydrate particles immersed in the liquid phase is V2, then the Saffman lift F S The calculation formula is as follows: In the above formula, r2′ represents the radius of the sphere whose volume is V2, ψ2′ represents the lateral sphericity of the hydrate particles immersed in the liquid phase, and ψ2 represents the sphericity of the hydrate particles immersed in the liquid phase.

[0012] Based on the first aspect, in some embodiments of the present invention, the adhesion force F between the hydrate particles and the pipe wall is... J The calculation formula is as follows: F J =3πr h σ sl In the above formula, σ sl It represents the interfacial tension between solid and liquid.

[0013] Based on the first aspect, in some embodiments of the present invention, if the hydrate particles are in equilibrium under forces in the vertical direction, without considering other vertical force components acting on the hydrate particles, the hydrate particles must satisfy the following force condition: F d -F G ′≤f(F J -F S ), where F d F represents the drag force experienced by the hydrate particles. G ′ represents the net gravitational force acting on the hydrate particles, f(F) J -F S This indicates the sliding friction force exerted on the hydrate particles by the contact surface of the inner wall of the pipe.

[0014] Based on the first aspect, in some embodiments of the present invention, the net gravitational force F experienced by the hydrate particles is... G The calculation method for ′ is as follows: The net gravity F acting on hydrate particles that are entirely in the liquid phase or entirely in the gas phase. G 'for: In the above formula, r h ρ represents the radius of the hydrate particle. h ρ represents the density of hydrate particles. l This represents the density of the gas or liquid phase. For hydrate particles that are not completely immersed in the liquid phase, assuming the volume of the hydrate particles not immersed in the liquid phase is V1, the net gravitational force on the hydrate particles is: In the above formula, ρ g ρ represents the density of the gas phase, g represents the acceleration due to gravity, and ρ represents the acceleration due to gravity. w This indicates the density of the liquid phase.

[0015] Based on the first aspect, in some embodiments of the present invention, the drag force F experienced by the hydrate particles is...d The calculation method is as follows: The drag force F acting on hydrate particles that are entirely in the liquid phase or entirely in the gas phase. d for: C D R represents the drag correction factor. h ρ represents the radius of the hydrate particle. l V represents the density of the gas or liquid phase. c Let v represent the velocity of the fluid at the centroid of the hydrate particle, and v represent the velocity of the hydrate particle. For hydrate particles that are not completely immersed in the liquid phase, the hydrate particle can be divided into two parts based on the liquid surface: a first part located in the gas phase and a second part located in the liquid phase. Assuming the volume of the first part is V1 and the volume of the second part is V2, the drag force on the hydrate particle is the sum of the forces on the two parts:

[0016]

[0017] In the above formula, F d1 F d2 These represent the drag forces acting on the first part and the second part, respectively. r1′ and r2′ represent the radii of the sphere with volume V1 and the sphere with volume V2, respectively. c1 The velocity v of the fluid at the center of mass of the first part represents the flow velocity of the fluid. c2 C represents the flow velocity of the fluid at the center of mass of the second part. D1 C D2 ρ represents the drag correction factor for the first part and the correction factor for the second part, respectively. g ρ w These represent the densities of the gas phase and the liquid phase, respectively.

[0018] Based on the first aspect, in some embodiments of the present invention, if the hydrate particles achieve total torque balance, then, neglecting rolling friction, the partial total torque M acting on the hydrate particles... D The following conditions must be met: M D =M d +(F S -F J )L1+(F d -F′ G L2≤0, in the above formula, F S F represents the Saffman lift force experienced by the hydrate particles. J F represents the adhesion force between hydrate particles and the pipe wall. d F represents the drag force experienced by the hydrate particles. G′ represents the net weight force acting on the hydrate particles, L1 and L2 represent the lever arm lengths of the horizontal and vertical forces, respectively, and M d This represents the additional torque generated by the stress of the fluid on the surface of the hydrate particles on the hydrate particles.

[0019] Based on the first aspect, in some embodiments of the present invention, the additional torque M d The calculation formula is as follows: The additional torque M acting on hydrate particles that are entirely in the liquid phase or entirely in the gas phase. d for: In the above formula, μ l The viscosity r represents the viscosity of the liquid or gas phase. h The radius of the hydrate particle is represented by v. c Let v represent the velocity of the fluid at the centroid of the hydrate particle, and v represent the velocity of the hydrate particle. For hydrate particles that are not completely immersed in the liquid phase, the hydrate particle can be divided into two parts based on the liquid surface: a first part located in the gas phase and a second part located in the liquid phase. Assuming the volume of the first part is V1 and the volume of the second part is V2, the additional torque on the hydrate particle can be calculated by the following formula:

[0020]

[0021] In the above formula, μ g μ w Let r1′ and r2′ represent the viscosities of the gas and liquid phases, respectively, and let v be the radii of the spheres with volumes V1 and V2, respectively. c1 The velocity v of the fluid at the center of mass of the first part represents the flow velocity of the fluid. c2 This indicates the flow velocity of the fluid at the center of mass of the second part.

[0022] The second aspect of this application provides a critical deposition determination device for hydrate particles under high gas-liquid ratio vertical pipe flow conditions, applicable to hydrate particles in contact with the inner wall of the pipe. The device includes: a determination module for determining whether the hydrate particles are in force balance; if so, the hydrate particles can be stably deposited on the inner wall of the pipe; if not, the hydrate particles cannot be stably deposited on the inner wall of the pipe.

[0023] Based on the second aspect, in some embodiments of the present invention, the judgment module includes: a first balance judgment unit, used to determine whether the hydrate particles are in force balance in the horizontal direction; a second balance judgment unit, used to determine whether the hydrate particles are in force balance in the vertical direction; and a third balance judgment unit, used to determine whether the total torque on the hydrate particles is balanced.

[0024] Based on the second aspect, in some embodiments of the present invention, the device further includes: a classification module: used to classify the contact mode between the hydrate particles and the inner wall of the tube, specifically including the following three categories: 1) when the hydrate particles are completely in the gas phase and in contact with the inner wall of the tube, it is direct contact; 2) when the hydrate particles are completely in the liquid phase and in contact with the inner wall of the tube, it is immersion contact; 3) when the hydrate particles are partially immersed in the liquid phase, and the part immersed in the liquid phase is in contact with the inner wall of the tube, while the remaining part is in the gas phase, it is semi-immersion contact.

[0025] The technical solution provided by this invention has the following beneficial effects:

[0026] 1. The embodiments of the present invention are designed for determining the deposition state of hydrate particles in annular and mist-like flow patterns in a tubular column, and are applicable to various high gas-liquid ratio flow conditions, covering a wide range of fields.

[0027] 2. In this embodiment of the invention, the determination of the deposition state of hydrate particles is based on the stress conditions of the particles. When the fluid flow parameters in the tubing are known, the deposition state of the particles can be easily determined.

[0028] 3. The embodiments of the present invention make up for the shortcomings of the previous "only using annular mist flow to replace annular flow and ignoring mist flow".

[0029] 4. The embodiments of the present invention simultaneously consider hydrate particle deposition under both annular and mist-like flow patterns under high gas-liquid ratio conditions, providing a more comprehensive consideration and helping to improve the accuracy of hydrate flow obstacle prediction, thus providing theoretical assistance for solving the problem of hydrate flow obstacle.

[0030] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0031] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings:

[0032] Figure 1 The diagram illustrates the direct contact between hydrate particles and the inner wall of the tube (hereinafter referred to as the tube wall) in the embodiment.

[0033] Figure 2 The illustration shows a schematic diagram of the immersion contact between hydrate particles and the inner wall of the tube (hereinafter referred to as the tube wall) in the embodiment;

[0034] Figure 3 The illustration shows a schematic diagram of the semi-immersion contact between the hydrate particles and the inner wall of the tube (hereinafter referred to as the tube wall) in the embodiment;

[0035] Figure 4 A schematic diagram of hydrate particles in semi-immersion contact is shown in the embodiment;

[0036] Figure 5 This schematic diagram illustrates the forces acting on the hydrate particles in contact with the wall in the embodiment.

[0037] Figure 6 The schematic diagram illustrates the structural block diagram of the critical deposition determination device for hydrate particles under high gas-liquid ratio vertical pipe flow conditions according to the embodiment;

[0038] Figure 7 The diagram schematically illustrates the internal structure of the computer device in the embodiment.

[0039] Explanation of reference numerals in the attached figures

[0040] 1-Judgment module; 11-First balance judgment unit; 12-Second balance judgment unit; 13-Third balance judgment unit; 2-Classification module. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0042] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0043] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0044] Current research uses "annular mist flow" instead of the concept of annular flow, neglecting the mist flow pattern. In fact, mist flow can further evolve from annular flow. When the water film in annular flow detaches from the wall and breaks into small droplets, until the liquid film on the pipe wall is completely atomized into small droplets and evenly distributed across the entire cross-section of the flow channel, and the gas phase is saturated natural gas, the gas and liquid phases have the same velocity, thus forming mist flow. In annular flow, the liquid phase exists in two forms: droplets in the gas phase and a liquid film at the pipe wall. The main difference between annular and mist flow is that there is no continuous liquid film in mist flow.

[0045] Regardless of particle size, hydrate particles in tubular columns under annular and mist-like flow conditions exist in two main states: suspension and wall contact. Suspension conditions determine whether hydrate particles can be carried by the fluid, while wall contact conditions determine whether they can adhere to the tube wall and form stable deposits. Currently, research on the suspension conditions of hydrate particles in tubular columns is relatively mature. Wall contact can be divided into three forms: direct wall contact, submerged wall contact, and semi-submerged wall contact (e.g.,...). Figures 1-3 As shown, since the hydrate particles have a wetted surface, the floating of annularly flowing particles on the liquid film surface can be disregarded. To determine the critical deposition criteria for hydrate particles, this embodiment of the invention provides a detailed analysis of the contact conditions between hydrate particles and the liquid film.

[0046] Example 1

[0047] This embodiment provides a method for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions, applicable to hydrate particles in contact with the inner wall of the pipe (i.e., the inner wall of the wellbore). The method includes:

[0048] Determine whether the hydrate particles are in force balance; if so, the hydrate particles can be stably deposited on the inner wall of the pipe; if not, the hydrate particles cannot be stably deposited on the inner wall of the pipe.

[0049] Furthermore, to improve the accuracy of the force balance analysis, in this embodiment, the force analysis of the hydrate particles is performed based on the contact methods between the hydrate particles and the inner wall of the tube, specifically including the following three types of contact methods:

[0050] 1) Direct contact, such as Figure 1 As shown, at this point, the hydrate particles are completely in the gas phase (gas core) (including the contact points).

[0051] 2) Immersion contact, such as Figure 2 As shown, the hydrate particles are completely in the liquid phase (liquid film).

[0052] 3) Semi-immersion contact, such as Figure 3 As shown, part of the hydrate particles are immersed in the liquid phase, and the part immersed in the liquid phase is in contact with the inner wall of the tube, while the other part is located in the gas phase.

[0053] Specifically, whether hydrate particles are in force equilibrium mainly includes the following three criteria:

[0054] A. Determine whether the hydrate particles are in equilibrium under forces in the horizontal direction;

[0055] If the hydrate particles are in equilibrium under horizontal forces, meaning they do not rise off the inner wall of the pipe, then the hydrate particles must satisfy the following force condition: F S ≤F J In the formula F S F represents the Saffman lift force experienced by the hydrate particles. J This represents the adhesive force between the hydrate particles and the pipe wall. (Of course, when the adhesive force is greater than the lift force, to ensure the hydrate particles are in a horizontal force balance, other force factors such as the reaction force of the pipe wall on the hydrate particles must also be considered. This is common knowledge and will not be elaborated here.)

[0056] A1. Specifically, the Saffman lift force F experienced by the hydrate particles... S It is obtained from the following calculation formula:

[0057] 1) The Saffman lift force F acting on hydrate particles completely immersed in the liquid phase S for:

[0058]

[0059] In the formula, r h The radius of the hydrate particles is expressed in meters (m) and ρ. w Density of the liquid phase, in kg / m³ 3 μ w The viscosity of the liquid phase is expressed in Pa·s; v w The velocity of the liquid phase is expressed in m / s; v represents the velocity of the hydrate particles in m / s; and y represents the distance from a point in the liquid film to the pipe wall in meters.

[0060] 2) Since the radial velocity gradient of the gas phase is negligible, the Saffman lift force on the direct contact hydrate particles that are completely in the gas phase (air) can be ignored.

[0061] 3) Calculate the Saffman lift force F experienced by hydrate particles partially immersed in the liquid phase. S In this case, only the portion immersed in the liquid phase is considered. Assuming the volume of the hydrate particles immersed in the liquid phase is V2, then the Saffman lift F S The calculation formula is as follows:

[0062]

[0063] In the above formula, r2′ represents the radius of a sphere with volume V2, ψ2′ represents the lateral sphericity of the hydrate particles immersed in the liquid phase, and ψ2 represents the sphericity of the hydrate particles immersed in the liquid phase.

[0064] A2. Specifically, the solid-solid adhesion force F between the hydrate particles and the pipe wall. J The calculation formula is as follows:

[0065] F J =3πr h σ sl (3)

[0066] In the above formula, σ sl This represents the interfacial tension between solid and liquid, expressed in N / m.

[0067] B. Determine whether the hydrate particles are in equilibrium under forces in the vertical direction;

[0068] If the hydrate particles are in equilibrium under forces in the vertical direction, meaning they will not slide along the inner wall of the pipe, then the hydrate particles must satisfy the following force condition: F d -F G ′≤f(F J -F S (Other vertical components are not considered here), where F d F represents the drag force experienced by the hydrate particles. G ′ represents the net gravitational force acting on the hydrate particles, f(F) J -F S This indicates the sliding friction force exerted on the hydrate particles by the contact surface of the inner wall of the pipe.

[0069] B1. Specifically, the net gravity F experienced by the hydrate particles G The calculation method for ′ is as follows:

[0070] The net gravitational force F acting on hydrate particles that are entirely in the liquid phase or entirely in the gas phase. G 'for:

[0071]

[0072] In the above formula, r h ρ represents the radius of the hydrate particle. h ρ represents the density of hydrate particles. l Indicates the density of the gas or liquid phase;

[0073] Please refer to Figure 4 For hydrate particles that are not completely immersed in the liquid phase, assume the volume of the hydrate particles not immersed in the liquid phase is V1 (unit: m³). 3If the net gravitational force on the hydrate particles is:

[0074]

[0075] In equation (5), ρ g ρ represents the density of the gas phase, and g represents the acceleration due to gravity.

[0076] B2. Specifically, the drag force F experienced by the hydrate particles d The calculation method is as follows:

[0077] The drag force F acting on hydrate particles that are entirely in the liquid phase or entirely in the gas phase d for:

[0078]

[0079] In equation (6), C D R represents the drag correction factor. h ρ represents the radius of the hydrate particle. l V represents the density of the gas or liquid phase. c The velocity v represents the flow velocity of the fluid at the center of mass of the hydrate particle, and the velocity v represents the velocity of the hydrate particle.

[0080] For hydrate particles that are not completely immersed in the liquid phase, they can be divided into two parts based on the liquid surface: a first part located in the gas phase and a second part located in the liquid phase, such as... Figure 4 As shown, Figure 4 In the diagram, h' represents the height of the first part, r' represents the radius of the tangent plane, point c1 represents the centroid of the first part, and point c2 represents the centroid of the second part.

[0081] Assuming the volume of the first part is V1 and the volume of the second part is V2, the drag force on the hydrate particles is calculated by adding the forces acting on the two parts:

[0082]

[0083] In equation (7), F d1 F d2 These represent the drag forces acting on the first part and the second part, respectively. r1′ and r2′ represent the radii of the sphere with volume V1 and the sphere with volume V2, respectively. c1 The velocity v of the fluid at the center of mass of the first part represents the flow velocity of the fluid. c2 C represents the flow velocity of the fluid at the center of mass of the second part. D1 C D2 ρ represents the drag correction factor for the first part and the correction factor for the second part, respectively. g ρw These represent the densities of the gas phase and the liquid phase, respectively.

[0084] The final drag force experienced by the particles that are not fully immersed in the liquid phase is:

[0085]

[0086] In equation (8), Ψ1 and Ψ1' represent the sphericity and transverse sphericity of the first part, respectively, which are dimensionless; ψ2 and ψ2′ represent the sphericity and transverse sphericity of the second part, respectively, which are dimensionless.

[0087] B3. The Saffman lift force F acting on the hydrate particles S The calculation method can be found in step A1.

[0088] B4. Solid-to-solid adhesion force between hydrate particles and pipe wall F J The calculation method can be found in step A2.

[0089] B5. The frictional force f(F) exerted on the hydrate particles by sliding at the contact surface of the inner wall of the pipe. J -F S The calculation of ) can refer to the conventional method for calculating sliding friction (i.e., adhesion force F). J With Saffman lift F S The difference is multiplied by the friction factor of the contact surface. Since this calculation is quite common, it will not be explained further here.

[0090] C. Determine whether the total torque on the hydrate particles is balanced.

[0091] If the hydrate particles are made to achieve total torque balance, that is, the hydrate particles will not roll around a point on the inner wall of the tube, then, neglecting rolling friction, the partial total torque M acting on the hydrate particles is... D The following conditions must be met:

[0092] M D =M d +(F S -F J )L1+(F d -F′ G L2≤0 (9)

[0093] In the above formula, F S F represents the Saffman lift force experienced by the hydrate particles. J F represents the adhesion force between hydrate particles and the pipe wall. d F represents the drag force experienced by the hydrate particles. G′ represents the net weight force acting on the hydrate particles, and L1 and L2 represent the lever arm lengths of the horizontal and vertical forces, respectively (specifically, in conjunction with...). Figure 5 Net weight F G Draw a straight line MN along the direction of the adhesion force F. J Draw a straight line PQ in the direction of the rolling point (L1 represents the distance from the rolling point to line PQ, L2 represents the distance from the rolling point to line MN), M d This represents the additional torque generated by the stress of the fluid on the surface of the hydrate particles on the hydrate particles.

[0094] Specifically, the torque acting on hydrate particles determines their rolling motion; the forces acting on hydrate particles are as follows: Figure 3 Taking the example shown below. In addition to the horizontal and vertical forces mentioned above, the stress of the fluid on the particle surface will also generate an additional torque on the hydrate particles, in the same direction as the direction that causes the particles to roll. Assuming that the hydrate particles have a tendency to roll upwards around the rolling point (fulcrum), then:

[0095] 1) The additional torque M acting on hydrate particles that are entirely in the liquid phase or entirely in the gas phase. d for:

[0096]

[0097] In equation (10), μ l The viscosity r represents the viscosity of the liquid or gas phase. h The radius of the hydrate particle is represented by v. c The velocity v represents the flow velocity of the fluid at the centroid of the hydrate particle, and the velocity v represents the velocity of the hydrate particle.

[0098] 2) For hydrate particles that are not completely immersed in the liquid phase, the hydrate particles can be divided into two parts based on the liquid surface: the first part located in the gas phase and the second part located in the liquid phase (see reference). Figure 4 Assuming the volume of the first part is V1 and the volume of the second part is V2, the additional torque on the hydrate particles can be calculated using the following formula:

[0099]

[0100] In equation (12), μ g μ w Let r1′ and r2′ represent the viscosities of the gas and liquid phases, respectively, and let v be the radii of the spheres with volumes V1 and V2, respectively. c1 The velocity v of the fluid at the center of mass of the first part represents the flow velocity of the fluid. c2 This indicates the flow velocity of the fluid at the center of mass of the second part.

[0101] By transforming equation (9), the condition for determining whether hydrate particles achieve total torque balance can be obtained as follows:

[0102] M d -(F J -F S L1≤(F G ′-F d L2

[0103] Based on the above-mentioned horizontal and vertical force balance criteria, in this embodiment, the force balance of hydrate particles must meet the following criteria:

[0104]

[0105] When hydrate particles satisfy all the criteria in equation (12), they will not rise, slip, or roll, and will be stably deposited on the inner wall of the pipe. Therefore, in practical applications, it is necessary to avoid this situation as much as possible to prevent hydrate particles from depositing on the inner wall of the pipe.

[0106] Example 2

[0107] In this embodiment, based on the determination method and parameter calculation method disclosed in Embodiment 1, a 3-inch tubing was used, with a fluid temperature of 20°C, a flow pressure of 15 MPa, and a liquid flow rate of 12 m³ / s. 3 / d, gas phase flow rate 25~50×10 4 m 3 Taking / d as an example, the detailed implementation of the present invention is as follows:

[0108] The particle size of hydrate particles can be calculated based on the droplet size in the gas core under mist / annular flow patterns. Since the droplet size under flow conditions is approximately normally distributed, the particle size of hydrate particles has similar characteristics.

[0109] For hydrate particles with a diameter of 300 μm, the gas phase flow rate is 25 × 10⁻⁶. 4 m 3 / d (annular flow pattern), the forces acting on the hydrate particles were calculated according to the calculation formulas provided in Example 1: Saffman lift, solid-solid adhesion, net weight, drag force, and torque. The calculation results are shown in Table 1.

[0110] Table 1. Stress and deposition state of hydrate particles (particle diameter 300 μm)

[0111]

[0112] Example 3

[0113] like Figure 6As shown, this embodiment provides a critical deposition determination device for hydrate particles under high gas-liquid ratio vertical pipe flow conditions, applicable to hydrate particles in contact with the inner wall of the pipe. The device includes: a determination module: used to determine whether the hydrate particles are in force balance; if so, the hydrate particles can be stably deposited on the inner wall of the pipe; if not, the hydrate particles cannot be stably deposited on the inner wall of the pipe.

[0114] Furthermore, the judgment module includes: a first balance judgment unit, used to judge whether the hydrate particles are in force balance in the horizontal direction; a second balance judgment unit, used to judge whether the hydrate particles are in force balance in the vertical direction; and a third balance judgment unit, used to judge whether the total torque on the hydrate particles is balanced.

[0115] Furthermore, the device also includes:

[0116] The classification module is used to classify the contact methods between the hydrate particles and the inner wall of the pipe, specifically including the following three categories: 1) When the hydrate particles are completely in the gas phase and in contact with the inner wall of the pipe, it is direct contact; 2) When the hydrate particles are completely in the liquid phase and in contact with the inner wall of the pipe, it is immersion contact; 3) When the hydrate particles are partially immersed in the liquid phase, and the part immersed in the liquid phase is in contact with the inner wall of the pipe, while the rest is in the gas phase, it is semi-immersion contact.

[0117] The critical deposition determination device for hydrate particles under high gas-liquid ratio vertical pipe flow conditions includes a processor and a memory. The aforementioned determination module and classification module are all stored as program units in the memory, and the processor executes the aforementioned program modules stored in the memory to realize the corresponding functions.

[0118] The processor contains a kernel, which retrieves the corresponding program unit from memory. One or more kernels can be configured, and adjusting kernel parameters allows for the determination of critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions.

[0119] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0120] This application provides a storage medium storing a program that, when executed by a processor, implements the above-described method for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions.

[0121] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 7As shown. The computer device includes a processor A01, a network interface A02, a memory (not shown), and a database (not shown) connected via a system bus. The processor A01 provides computing and control capabilities. The memory includes internal memory A03 and a non-volatile storage medium A04. The non-volatile storage medium A04 stores an operating system B01, a computer program B02, and a database (not shown). The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 stored in the non-volatile storage medium A04. The database stores data on a critical deposition determination method for hydrate particles under high gas-liquid ratio vertical pipe flow conditions. The network interface A02 communicates with external terminals via a network connection. When the processor A01 executes the computer program B02, it implements a critical deposition determination method for hydrate particles under high gas-liquid ratio vertical pipe flow conditions.

[0122] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0123] In one embodiment, the critical deposition determination device for hydrate particles under high gas-liquid ratio vertical pipe flow conditions provided in this application can be implemented as a computer program. The computer program can be implemented in various ways, such as... Figure 7 The computer device shown operates on this device. The computer device's memory can store various program modules that constitute the critical deposition determination device for hydrate particles under high gas-liquid ratio vertical pipe flow conditions. The computer program, composed of these program modules, causes the processor to execute the steps in the critical deposition determination method for hydrate particles under high gas-liquid ratio vertical pipe flow conditions described in the various embodiments of this application.

[0124] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0125] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0126] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0127] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0128] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0129] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, like read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0130] Computer-readable media include both permanent and non-permanent, removable and non-removable media, which can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0131] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0132] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions, characterized in that, The method, applicable to hydrate particles in contact with the inner wall of a pipe, includes: The contact methods between the hydrate particles and the inner wall of the tube can be classified into the following three categories: 1) When the hydrate particles are completely in the gas phase and in contact with the inner wall of the tube, it is considered direct contact; 2) When the hydrate particles are completely in the liquid phase and in contact with the inner wall of the tube, it is an immersion contact; 3) When the hydrate particles are partially immersed in the liquid phase and the part immersed in the liquid phase is in contact with the inner wall of the tube, while the rest is located in the gas phase, it is a semi-immersion contact. Determine whether hydrate particles are in force equilibrium; If so, the hydrate particles can be stably deposited on the inner wall of the pipe; if not, the hydrate particles cannot be stably deposited on the inner wall of the pipe. For hydrate particles to be in equilibrium, the following equilibrium conditions must be met: 1) The forces are in equilibrium in the horizontal direction; 2) The forces are balanced in the vertical direction; 3) The total torque is balanced; If the hydrate particles are in equilibrium under horizontal forces, and disregarding other horizontal forces acting on the hydrate particles, the hydrate particles must satisfy the following force conditions: In the formula This represents the Saffman lift force experienced by the hydrate particles. This represents the adhesion force between the hydrate particles and the pipe wall; the Saffman lift force experienced by the hydrate particles that are directly in contact with the wall and are completely in the gas phase is negligible. If the hydrate particles are in equilibrium under vertical forces, and without considering other vertical force components acting on the hydrate particles, the hydrate particles must satisfy the following force conditions: In the formula, This represents the drag force experienced by the hydrate particles. This represents the net gravitational force acting on the hydrate particles. This indicates the sliding friction force exerted on the hydrate particles by the contact surface of the inner wall of the pipe. If the hydrate particles are made to achieve total torque balance, then, neglecting rolling friction, the portion of the total torque acting on the hydrate particles... M D The following conditions must be met: ≤0； In the above formula, , These represent the lever arm lengths of the horizontal force and the lever arm lengths of the vertical force, respectively. This represents the additional torque generated by the stress of the fluid on the surface of the hydrate particles on the hydrate particles.

2. The method for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions according to claim 1, characterized in that, The hydrate particles are subjected to Saffman lift. It is obtained from the following calculation formula: Saffman lift force on hydrate particles fully immersed in the liquid phase for: In the formula, This represents the radius of the hydrate particles. ρ l This indicates the density of the liquid phase. µ l Indicates the viscosity of the liquid phase. Indicates the flow rate of the liquid phase. Indicates the velocity of hydrate particles. This indicates the distance from a point within the liquid film to the tube wall; Calculate the Saffman lift force on hydrate particles partially immersed in the liquid phase. In this case, only the portion immersed in the liquid phase is considered, assuming the volume of the hydrate particles immersed in the liquid phase is... Then Saffman lift The calculation formula is as follows: In the above formula, The volume is The radius of the sphere, This indicates the lateral sphericity of the hydrate particles immersed in the liquid phase. This indicates the sphericity of the hydrate particles immersed in the liquid phase.

3. The method for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions according to claim 1, characterized in that, The adhesion between the hydrate particles and the pipe wall The calculation formula is as follows: In the above formula, σ sl It represents the interfacial tension between solid and liquid.

4. The method for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions according to claim 1, characterized in that, The net weight force on the hydrate particles The calculation method is as follows: The net gravity acting on hydrate particles that are entirely in the liquid phase or entirely in the gas phase. for: In the above formula, This represents the radius of the hydrate particles. ρ h This indicates the density of the hydrate particles. ρ l Indicates the density of the gas or liquid phase; For hydrate particles that are not completely immersed in the liquid phase, assume the volume of the hydrate particles not immersed in the liquid phase is... Then the net gravitational force on the hydrate particles is: In the above formula, ρ g This represents the density of the gas phase. g Represents gravitational acceleration. ρ w This indicates the density of the liquid phase.

5. The method for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions according to claim 1, characterized in that, The drag force on the hydrate particles The calculation method is as follows: Dragging force on hydrate particles that are entirely in the liquid phase or entirely in the gas phase F d for: C D This represents the drag correction factor. This represents the radius of the hydrate particles. ρ l This indicates the density of the gas or liquid phase. This indicates the flow velocity of the fluid at the center of mass of the hydrate particle. This indicates the velocity of the hydrate particles. For hydrate particles that are not completely immersed in the liquid phase, the particles can be divided into two parts based on the liquid surface: a first part located in the gas phase and a second part located in the liquid phase. Let the volume of the first part be... The volume of the second part is The drag force on the hydrate particles is then summed according to the forces acting on the two parts: In the above formula, F d1 , F d2 These represent the drag forces acting on the first part and the second part, respectively. , They represent volumes respectively. The radius and volume of the sphere are The radius of the sphere, v c1 This indicates the fluid flow velocity at the centroid of the first part. v c2 This indicates the fluid flow velocity at the center of mass of the second part. C D1 , C D2 These represent the drag correction coefficients for the first part and the correction coefficients for the second part, respectively. ρ g , ρ w These represent the densities of the gas phase and the liquid phase, respectively.

6. The method for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions according to claim 1, characterized in that, The additional torque The calculation formula is as follows: Additional torque on hydrate particles that are entirely in the liquid phase or entirely in the gas phase for: In the above formula, µ l Indicates the viscosity of the liquid or gas phase. This represents the radius of the hydrate particles. This indicates the flow velocity of the fluid at the center of mass of the hydrate particle. This indicates the velocity of the hydrate particles. For hydrate particles that are not completely immersed in the liquid phase, the particles can be divided into two parts based on the liquid surface: a first part located in the gas phase and a second part located in the liquid phase. Let the volume of the first part be... The volume of the second part is The additional torque acting on the hydrate particles can be calculated using the following formula: In the above formula, µ g , µ w These represent the viscosity of the gas phase and the viscosity of the liquid phase, respectively. , They represent volumes respectively. The radius and volume of the sphere are The radius of the sphere, v c1 This indicates the fluid flow velocity at the centroid of the first part. v c2 This indicates the flow velocity of the fluid at the center of mass of the second part.

7. A device for determining the critical deposition of hydrate particles under high gas-liquid ratio vertical pipe flow conditions, characterized in that, The device is suitable for hydrate particles in contact with the inner wall of a pipe, and includes: Classification module: used to classify the contact methods between the hydrate particles and the inner wall of the tube, specifically including the following three categories: 1) When the hydrate particles are completely in the gas phase and in contact with the inner wall of the tube, it is considered direct contact; 2) When the hydrate particles are completely in the liquid phase and in contact with the inner wall of the tube, it is an immersion contact; 3) When the hydrate particles are partially immersed in the liquid phase and the part immersed in the liquid phase is in contact with the inner wall of the tube, while the rest is located in the gas phase, it is a semi-immersion contact. Judgment module: Used to determine whether hydrate particles are in force equilibrium; If so, the hydrate particles can be stably deposited on the inner wall of the pipe; if not, the hydrate particles cannot be stably deposited on the inner wall of the pipe. The judgment module includes: The first balance judgment unit is used to determine whether the hydrate particles are in a horizontal force balance. The second balance judgment unit is used to determine whether the hydrate particles are in force balance in the vertical direction; The third balance judgment unit is used to determine whether the total torque on the hydrate particles is balanced; If the hydrate particles are in equilibrium under horizontal forces, and disregarding other horizontal forces acting on the hydrate particles, the hydrate particles must satisfy the following force conditions: In the formula This represents the Saffman lift force experienced by the hydrate particles. This represents the adhesion force between the hydrate particles and the pipe wall; the Saffman lift force experienced by the hydrate particles that are directly in contact with the wall and are completely in the gas phase is negligible. If the hydrate particles are in equilibrium under vertical forces, and without considering other vertical force components acting on the hydrate particles, the hydrate particles must satisfy the following force conditions: In the formula, This represents the drag force experienced by the hydrate particles. This represents the net gravitational force acting on the hydrate particles. This indicates the sliding friction force exerted on the hydrate particles by the contact surface of the inner wall of the pipe. If the hydrate particles are made to achieve total torque balance, then, neglecting rolling friction, the portion of the total torque acting on the hydrate particles... M D The following conditions must be met: ≤0； In the above formula, , These represent the lever arm lengths of the horizontal force and the lever arm lengths of the vertical force, respectively. This represents the additional torque generated by the stress of the fluid on the surface of the hydrate particles on the hydrate particles.

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