Transient component tracking method and device applicable to oil and gas field condensate pipeline networks

Abstract

This invention provides a transient component tracking method and apparatus for condensate pipeline networks in oil and gas fields. The method includes: predicting the component change at any location within the condensate pipeline network based on a pre-established pipeline network control model and the initial composition within the condensate pipeline network, wherein the pipeline network control model is used to characterize the component state parameters at any location within the condensate pipeline network; and predicting the phase change at each location within the condensate pipeline network based on the component change. On the one hand, this invention can dynamically track the composition of the fluid within the pipeline; on the other hand, this invention calculates phase variables and related flow parameters in real time based on the fluid composition, pressure, and temperature of each pipeline segment, thus realizing component tracking of natural gas condensate pipeline networks.

Description

Technical Field

[0001] This invention relates to the field of marine oil and gas transportation technology, and particularly to the field of component tracking technology for natural gas condensate pipeline networks, specifically to a transient component tracking method and apparatus suitable for oil and gas field condensate pipeline networks. Background Technology

[0002] Offshore oil and gas resources, as an important component of oil and gas resources, possess enormous development and utilization potential. Driven by increasing energy demand, especially the demand for clean energy such as natural gas, the scale of offshore gas field development is gradually expanding. Offshore pipelines, as the main arteries for transporting offshore oil and gas, are hailed as the lifeline of offshore oil and gas production systems and are a key technological link in offshore oil development.

[0003] In recent years, the operation of offshore oil and gas mixed-transmission pipeline networks has undergone many new changes, mainly in three aspects: (1) The transmission method of gas-liquid multiphase flow has been widely used. In offshore gas field development, gas well products are transported to processing platforms or onshore terminals through multiphase pipelines, often with a length of tens of kilometers. At the same time, it is impossible to set up temperature and pressure monitoring instruments along the line, making operation and management difficult; (2) The mileage of offshore gas transmission pipeline networks has increased rapidly. In offshore gas field production, in order to reduce production costs, production platforms often control multiple wells, and the output of each well is transported to the platform, thus forming a complex subsea pipeline network; (3) Downstream users have put forward stricter requirements for oil and gas transportation. In order to ensure the safety of the production process, customers have put forward higher requirements for the quality of natural gas produced by offshore gas fields. In addition to traditional pressure and flow rate, calorific value, total hydrocarbon content, methane ratio, carbon dioxide content, nitrogen content, etc. are also involved. Therefore, it is urgent to study natural gas condensate oil pipeline networks and develop component tracking technology for oil and gas multiphase transmission pipeline networks to predict the changes in fluid composition in the pipeline network during the pipeline transportation process. Summary of the Invention

[0004] To address the problems in existing technologies, this invention can dynamically track the composition of fluids within pipes, and simultaneously calculate phase variables and related flow parameters in real time based on the fluid composition, pressure, and temperature of each pipe section, thus realizing component tracking of natural gas condensate pipeline networks.

[0005] In a first aspect, the present invention provides a transient component tracking method applicable to oil and gas field condensate pipeline networks, comprising:

[0006] The composition change at any location in the condensate pipeline network is predicted based on the pre-established pipeline network control model and the initial composition in the condensate pipeline network, wherein the pipeline network control model is used to characterize the composition state parameters at any location in the condensate pipeline network.

[0007] Predict the phase change at each location within the condensate pipeline network based on the changes in the composition.

[0008] In one embodiment, predicting the phase change at each location within the condensate pipeline network based on the component changes includes:

[0009] Based on the changes in the composition, a gas-liquid phase state equation is established for the condensate pipeline network. This gas-liquid phase state equation is used to predict the gas-liquid phase distribution of the condensate pipeline network.

[0010] The phase change at each location within the condensate pipeline network is predicted based on the gas-liquid phase state equation.

[0011] In one embodiment, the transient component tracking method applicable to oil and gas field condensate pipeline networks further includes:

[0012] The composition change and the phase change are updated according to the gas-liquid phase equation of state.

[0013] In one embodiment, establishing the pipeline network control model includes the following steps:

[0014] Establish a control model for the pipeline based on the component state parameters at any location within the pipeline;

[0015] Establish a control model for the connection point based on the component state parameters of the connection point between multiple pipelines;

[0016] The pipeline control model is established based on the control models of multiple pipelines and the control models of multiple connection points, wherein the control model of multiple pipelines corresponds to multiple pipelines, and the control model of multiple connection points corresponds to multiple connection points.

[0017] In one embodiment, the component state parameters include temperature, pressure, and flow rate.

[0018] Secondly, the present invention provides a transient component tracking device suitable for oil and gas field condensate pipeline networks, the device comprising:

[0019] The component change prediction module is used to predict the component change at any location in the condensate pipeline network based on a pre-established pipeline network control model and the initial components in the condensate pipeline network, wherein the pipeline network control model is used to characterize the component state parameters at any location in the condensate pipeline network.

[0020] The phase change prediction module is used to predict the phase change at each location in the condensate pipeline network based on the component changes.

[0021] In one embodiment, the phase change prediction module includes:

[0022] The equation of state establishment unit is used to establish the gas-liquid phase equation of state of the condensate pipeline network based on the component changes. The gas-liquid phase equation of state is the PR equation of state, which is used to predict the gas-liquid phase distribution of the condensate pipeline network.

[0023] A phase change prediction unit is used to predict the phase change at each location in the condensate pipeline network based on the gas-liquid phase state equation.

[0024] In one embodiment, the transient component tracking device suitable for oil and gas field condensate pipeline networks further includes:

[0025] An iterative update module is used to update the component changes and phase changes according to the gas-liquid phase state equation.

[0026] In one embodiment, the transient component tracking device suitable for oil and gas field condensate pipeline networks further includes:

[0027] A pipeline control model establishment module, used to establish the pipeline control model, the pipeline control model establishment module includes:

[0028] The single-pipe control model establishment unit is used to establish the control model of a single pipe based on the component state parameters at any location within the single pipe.

[0029] The connection point control model establishment unit is used to establish the control model of the connection point based on the component state parameters of the connection point between multiple pipelines.

[0030] The pipeline control model establishment unit is used to establish the pipeline control model based on the control models of multiple pipelines and the control models of multiple connection points, wherein the control models of multiple pipelines correspond to multiple pipelines, and the control models of multiple connection points correspond to multiple connection points.

[0031] In one embodiment, the component state parameters include temperature, pressure, and flow rate.

[0032] Thirdly, the present invention provides a computer program product, including a computer program / instruction that, when executed by a processor, implements the steps of an integrated prediction method for conventional and unconventional oil and gas reservoirs.

[0033] Fourthly, the present invention provides an electronic device, including a memory, a processor, and a deterministic program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of a transient component tracking method applicable to oil and gas field condensate pipeline networks.

[0034] Fifthly, the present invention provides a deterministic machine-readable storage medium having a deterministic machine program stored thereon, which, when executed by a processor, implements the steps of a transient component tracking method applicable to oil and gas field condensate pipeline networks.

[0035] As can be seen from the above description, the transient component tracking method and apparatus for oil and gas field condensate pipeline networks provided in the embodiments of the present invention predict the component changes at any location in the condensate pipeline network based on a pre-established pipeline network control model and the initial components in the condensate pipeline network. The pipeline network control model is used to characterize the component state parameters at any location in the condensate pipeline network. Then, the phase change at each location in the condensate pipeline network is predicted based on the component changes.

[0036] Based on the established gas-liquid two-phase flow simulation algorithm, this application establishes component equations considering phase changes for both pipelines and connection points. Next, the gas-phase-based phase change model is extended to each component, forming a phase change model for natural gas condensate based on each component. Then, a fluid state equation is introduced to calculate the equilibrium state of each component in real time. Finally, based on the relationship between flow simulation, component calculation, and phase equilibrium flashing, a component tracking algorithm for natural gas condensate pipeline networks is established. This algorithm can dynamically track the composition of the fluid within the pipe and, based on the fluid composition, pressure, and temperature of each pipe section, calculate phase variables and related flow parameters in real time, thus realizing component and phase change tracking of the natural gas condensate pipeline network. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a flowchart illustrating a transient component tracking method for oil and gas field condensate pipeline networks, as described in an embodiment of the present invention. Figure 1 ;

[0039] Figure 2 This is a flowchart illustrating a transient component tracking method for oil and gas field condensate pipeline networks, as described in an embodiment of the present invention. Figure 2 ;

[0040] Figure 3 This is a flowchart illustrating a transient component tracking method for oil and gas field condensate pipeline networks, as described in an embodiment of the present invention. Figure 3 ;

[0041] Figure 4 This is a schematic diagram illustrating the interaction between the component level, phase level, and equation of state in an embodiment of the present invention;

[0042] Figure 5 This is a flowchart illustrating a transient component tracking method for oil and gas field condensate pipeline networks, as described in an embodiment of the present invention. Figure 4 ;

[0043] Figure 6 This is a flowchart illustrating step 500 in an embodiment of the present invention;

[0044] Figure 7 This is a flowchart illustrating a transient component tracking method applicable to oil and gas field condensate pipeline networks in a specific application example of the present invention.

[0045] Figure 8 This is a schematic diagram of a gathering and transmission pipeline network structure in a specific application example of the present invention;

[0046] Figure 9 This is a schematic diagram of the pressure results along the line in a specific application example of the present invention;

[0047] Figure 10 This is a schematic diagram of the temperature results along the line in a specific application example of the present invention;

[0048] Figure 11 This is a schematic diagram showing the density of C1 in the gas phase along the line in a specific application example of the present invention.

[0049] Figure 12 This is a schematic diagram showing the density of C1 in the liquid phase along the line in a specific application example of the present invention;

[0050] Figure 13 This is a schematic diagram showing the density of H2 in the gas phase along the line in a specific application example of the present invention.

[0051] Figure 14 This is a schematic diagram showing the density of H2 in the liquid phase along the line in a specific application example of the present invention;

[0052] Figure 15 This is a schematic diagram showing the mass flow rate of gas phase C1 along the line in a specific application example of the present invention;

[0053] Figure 16 This is a schematic diagram showing the mass flow rate of liquid phase C1 along the line in a specific application example of the present invention;

[0054] Figure 17 This is a schematic diagram showing the total mass flow rate along line C1 in a specific application example of the present invention;

[0055] Figure 18 This is a schematic diagram showing the mass flow rate of gas phase H2 along the line in a specific application example of the present invention;

[0056] Figure 19 This is a schematic diagram showing the mass flow rate of liquid phase H2 along the line in a specific application example of the present invention;

[0057] Figure 20This is a schematic diagram showing the total mass flow rate along line H2 in a specific application example of the present invention;

[0058] Figure 21 This is a schematic diagram of the transient component tracking device for oil and gas field condensate pipeline networks in an embodiment of the present invention;

[0059] Figure 22 This is a schematic diagram of the structure of an electronic device in an embodiment of the present invention. Detailed Implementation

[0060] 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, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or deterministic program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a deterministic program product implemented on one or more deterministic storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing deterministic program code.

[0062] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product or device.

[0063] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0064] The embodiments of the present invention provide a specific implementation of a transient component tracking method applicable to oil and gas field condensate pipeline networks, see [link to relevant documentation]. Figure 1 The method specifically includes the following:

[0065] Step 100: Predict the composition change at any location in the condensate pipeline network based on the pre-established pipeline network control model and the initial composition in the condensate pipeline network, wherein the pipeline network control model is used to characterize the composition state parameters at any location in the condensate pipeline network.

[0066] Step 200: Predict the phase change at each location in the condensate pipeline network based on the component changes.

[0067] As described above, the transient component tracking method for condensate pipeline networks in oil and gas fields provided in this application involves a combination of flow simulation, component calculation, and phase equilibrium flash evaporation. Specifically, based on the established gas-liquid two-phase flow simulation algorithm, component equations considering phase changes are established for both pipelines and connection points. Next, the gas-phase-based phase change model is extended to each component, forming a phase change model for natural gas condensate based on each component. Then, the fluid state equation is introduced to calculate the equilibrium state of each component in real time. Finally, based on the relationship between flow simulation, component calculation, and phase equilibrium flash evaporation, a component tracking algorithm for natural gas condensate pipeline networks is established. This algorithm can dynamically track the composition of the fluid within the pipe and, based on the fluid composition, pressure, and temperature of each pipe section, calculate the phase variables and related flow parameters in real time, thus realizing component tracking for natural gas condensate pipeline networks.

[0068] In one embodiment, "prediction" in step 100 refers to determining the component change at any time and any location within the condensate pipeline network. Furthermore, the condensate pipeline network consists of multiple individual pipes and intermediate connection points. The connection points connect at least two individual pipes, and the specifications of the individual pipes and connection points can be the same or different.

[0069] In addition, the component change in step 200 refers to the change in the composition content of C1, C2...C10 substances in the condensate pipeline network, and the phase change refers to the change in the gas-liquid ratio and the change in the mass of the gas and liquid phases in the condensate pipeline network.

[0070] Natural gas condensate pipeline networks typically contain multiple fluid sources, each with a generally different composition. Consider how to calculate the phase change in the flow when the fluid composition is constantly changing. The phase change can be calculated from the perspective of a single component as follows:

[0071]

[0072] In the formula, X e,i This parameter represents the proportion of the mass of component i in the gas phase to the total mass of component i under equilibrium conditions. It is related to both the composition of the fluid and its state, and can be expressed as:

[0073] X e,i=F(z,p,T) (2)

[0074] In the formula, z is the total fluid composition expressed as a mole fraction, p is the pressure of the fluid, and T is the temperature of the fluid. Then, a parameter is introduced into formula (2): the total fluid composition z. Since natural gas condensate has both gas and liquid phases during flow, and the flow velocities of the gas and liquid phases are often different, its composition cannot be described by a single phase. In this application, the total fluid composition is determined as follows:

[0075]

[0076]

[0077] In the formula, m i M represents the total molar flow rate of the i-th component at the studied location, in mol / s; i Let be the molar mass of the i-th component, kg / mol. Equations (3) and (4) introduce the gas phase velocity v when calculating the overall fluid composition. g and liquid phase velocity v l Therefore, it fully considers the velocity difference between the gas and liquid phases and can reflect the influence of flow on the overall composition calculation.

[0078] In one embodiment, see Figure 2 The transient component tracking method applicable to oil and gas field condensate pipeline networks also includes:

[0079] Step 300: Determine the component changes based on the gas-liquid phase equation of state of the condensate pipeline network. The gas-liquid phase equation of state is the PR equation of state, which is used to predict the gas-liquid phase distribution of the condensate pipeline network.

[0080] In the field of phase behavior technology for petroleum fluids, cubic equations of state are typically used for phase equilibrium calculations. This application employs the more adaptable PR equation of state to predict the gas-liquid phase distribution of natural gas condensate. This equation can be expressed as:

[0081]

[0082] In the formula, a and b are two characteristic parameters. For a pure substance composed of a single component, a and b can be directly obtained from relevant literature; for a mixture composed of multiple components, a and b are obtained from the parameters of each component constituting the fluid according to specific mixing rules. This application uses the following mixing rules to determine these two characteristic parameters of natural gas condensate:

[0083]

[0084] Equation (5) is the equation of state expressed in terms of molar volume. This equation can also be converted into the form of compressibility factor Z, as shown below:

[0085]

[0086] Based on equations (5) to (7), the fugacity of a single component in natural gas condensate can be expressed by the following formula:

[0087]

[0088]

[0089] a ij =(a i a j ) 0.5 (1-k ij (10)

[0090] In equations (8) to (10), f g,i f represents the fugacity of the i-th component in the gas phase. l,i y represents the fugacity of the i-th component in the liquid phase. j x represents the mole fraction of each component in the gas phase. j k represents the mole fraction of each component in the liquid phase. ij This represents the interaction parameter between the i-th and j-th components. The purpose of phase equilibrium calculations is to obtain the equilibrium phase fraction X of each component. e,i To satisfy:

[0091] f g,i =f l,i (11)

[0092] The physical properties of the gas and liquid phases during the flow process are also calculated separately using various physical property models (formulas (35), (36) to (39)) based on the local fluid composition, temperature and pressure.

[0093] In one embodiment, see Figure 3 The transient component tracking method applicable to oil and gas field condensate pipeline networks also includes:

[0094] Step 400: Update the component changes and phase changes according to the gas-liquid phase state equation.

[0095] See Figure 4To achieve component tracking in natural gas condensate pipeline networks, this application describes the flow at two levels: at the phase level, mass and momentum equations are provided for the gas and liquid phases respectively, and a mixing energy equation is also given for the gas and liquid phases as a whole; at the component level, for cases where a component may appear in both the gas and liquid phases simultaneously, two component equations are provided for each component to track its movement in the gas and liquid phases respectively. Since phase transitions also occur during the flow, state equations are used to describe these phase transitions at both levels. The relationship between these three is as follows: Figure 4 As shown.

[0096] exist Figure 4 Of the three parts shown, the simulation of the macroscopic fluid phase layer is the foundation of the entire simulation. Flow parameters of the natural gas condensate pipeline network are calculated at this layer, including the volume fraction, density, and velocity of the gas and liquid phases, as well as pressure and temperature data at various locations within the pipeline network. These flow parameters are correlated with the simulation of the microscopic fluid component layer through equations (12) and (13), simultaneously providing the basis for the calculation of the equation of state. At the microscopic fluid component layer, the phase layer simulation provides a new velocity distribution, thus allowing for density updates of each component based on the convection equation. To achieve component-based phase change calculations, the equation of state utilizes the density and flow information of each component provided by the microscopic fluid component layer and the phase layer to calculate the fluid component z of each micro-element pipe segment. Then, the equation of state obtains the equilibrium phase fraction X of each component through phase equilibrium calculations. e,i And the overall equilibrium phase fraction X e This allows for the calculation of phase variables from both the component and phase levels.

[0097]

[0098] In one embodiment, see Figure 5 The transient component tracking method applicable to oil and gas field condensate pipeline networks also includes:

[0099] Step 500: Establish the pipeline network control model. Further, see... Figure 6 Step 500 includes:

[0100] Step 501: Establish a control model for the pipeline based on the component state parameters at any location within the pipeline;

[0101] Under the two-fluid model, the flow equations for the natural gas condensate pipeline include the following five:

[0102]

[0103]

[0104]

[0105]

[0106]

[0107] Equations (14) to (17) are hydraulic equations, and equation (18) is a thermodynamic equation. g α1 and ρ are the phase inclusions of the gas and liquid phases, respectively; g ρ1 and ρ2 are the densities of the gas and liquid phases, respectively, in kg / m³. 3 ;v g v1 and v2 are the flow velocities of the gas and liquid phases, respectively, in m / s; Φ g and Φ l These represent the mass changes of the gas and liquid phases caused by phase change during the flow process, in kg / (m³). 3 ·s); p is the pressure at the location of the pipeline, Pa; θ is the angle between the pipeline axis and the horizontal direction, rad; τ wg and τ wl Here, represents the shear stress between the gas and liquid phases and the pipe wall, respectively, in Pa; A is the cross-sectional area of ​​the pipe, in m. 2 S g and S l τ represents the wetted perimeter length of the gas and liquid phases on the cross-section, in meters; i The shear stress between the gas and liquid phases is expressed in Pa and S. i v is the length of the gas-liquid boundary line on the cross-section, in meters (m); i Let be the flow velocity of the fluid undergoing a phase change before the phase change, in m / s. Let Q be the heat exchanged between the fluid and its surroundings during the flow process, in W / m³. 3 C p is the isobaric specific heat capacity of the fluid, J / (kg·K); T is the temperature of the fluid, K.

[0108] In equations (14) to (17), the phase content α of the gas-liquid phase and the phase variable Φ between the gas and liquid phases also satisfy the following constraints:

[0109] α g +α l =1 (19)

[0110] Φ g +Φ l =0 (20)

[0111] Natural gas condensate pipelines contain both gas and liquid fluids, and each component typically exists in both the gas and liquid phases simultaneously. Therefore, when performing component tracking, two density equations are required for each component: one for the gas phase and another for the liquid phase, as shown below:

[0112]

[0113]

[0114] In the formula, ρ g,i Let be the density of the i-th component in the gas phase, kg / m³ 3 ;ρ l,i Let be the density of the i-th component in the liquid phase, kg / m³ 3 ;φ g,i Let i be the mass of the i-th component that changes from the liquid phase to the gas phase, in kg / (m³). 3 ·s); φ l,i Let be the mass of the i-th component that changes from the gas phase to the liquid phase, in kg / (m³). 3 ·s). If a natural gas condensate contains n components, then there are 2n component equations. For any one of these components, its phase variables satisfy the following constraints:

[0115] φ g,i +φ l,i =0 (23)

[0116] The phase variables of each component and the total phase variable between the gas and liquid phases have the following relationship:

[0117]

[0118]

[0119] At the same time, there is a similar relationship between the density of each phase and the density of each component in that phase:

[0120]

[0121]

[0122] Step 502: Establish a control model for the connection point based on the component state parameters of the connection point between multiple pipelines;

[0123] For the connection point of the natural gas condensate pipeline network, the main control volume is placed at the center of the connection point, while a velocity control volume is placed on each of the surrounding pipelines. The mass equation for the main control volume is as follows:

[0124]

[0125]

[0126] Equations (28) and (29) indicate that mass exchange between phases is not considered at the junction point, and it is assumed that the gas and liquid phases only mix at that point. In the equations, ΔV is the volume at the junction point, m... 3S represents the area of ​​each of its surfaces, in m 2 ; Let be the gas-liquid phase velocity in vector form, in m / s; Let be the direction of the outward normal to each surface.

[0127] Phase-to-phase exchange is not considered in the velocity control volume around the connection point, and the velocity control equations are as follows:

[0128]

[0129]

[0130] The temperature equation at the junction can be expressed as:

[0131]

[0132] Similar to the mass equation, the temperature equation at the junction point has also been simplified, considering only the mixing of the incoming flow and heat exchange with the environment, while ignoring the effects of pressure, friction, and other factors on the work done by the fluid.

[0133] The above are the governing equations for hydrothermal simulation at the junction. To track the mixing process of the various components of the natural gas condensate at the junction, a component equation also needs to be derived for the junction, which can be expressed as:

[0134]

[0135]

[0136] Since the effect of phase transition is ignored in the mass equation at the junction, phase transition terms no longer appear in the equations of each component, and only the mixing of the incoming streams is represented.

[0137] Step 503: Establish the pipeline control model based on the control models of multiple pipelines and the control models of multiple connection points, wherein the control model of multiple pipelines corresponds to multiple pipelines, and the control model of multiple connection points corresponds to multiple connection points.

[0138] In one embodiment, the component state parameters include temperature, pressure, and flow rate.

[0139] To further illustrate this solution, the present invention provides a specific application example of a transient component tracking method suitable for oil and gas field condensate pipeline networks, using a natural gas condensate gathering and transportation pipeline network as an example. Figure 7 This is a schematic diagram illustrating the specific algorithm flow for a transient component tracking method applicable to oil and gas field condensate pipeline networks. Figure 7 In this context, μ represents the viscosity of natural gas, which is calculated using the corresponding state model:

[0140]

[0141] If the pressure p, temperature T, and density ρ of each component of natural gas are... i Given that its molar volume V can be determined, the density of natural gas can also be determined by the following formula:

[0142]

[0143] In equation (36), M is the molar mass of natural gas. The specific heat capacity of natural gas at constant pressure, C... p Determine using the following formula:

[0144]

[0145] Meanwhile, the specific heat capacity of natural gas at constant volume is determined according to the following formula:

[0146]

[0147] Having obtained these two specific heat capacities of natural gas, the speed of sound in natural gas under this condition can be determined by the following formula:

[0148]

[0149] The governing equations used for component tracking in natural gas condensate pipeline networks are still discretized on an interlaced grid. For example... Figure 7 As shown, after the calculation begins, the momentum equation and pressure correction equation are solved first to complete the mutual correction process between velocity and pressure. After this step is completed, the program starts to solve the mass equation to obtain the phase content of each phase. It should be noted that the density of the gas and liquid phases is also corrected according to the pressure correction result during the pressure and velocity correction process. This will lead to the inconsistency between the density described at the phase level and the density described at the component level (i.e., it cannot satisfy equations (26) and (27)). Therefore, a component density correction step is introduced in the simulation: after the velocity and pressure are matched, the density of each component is corrected according to equations (12) and (13), and then the fluid temperature is calculated. Next, the program enters the fluid phase equilibrium calculation part. In this stage, the total composition of the fluid is calculated by summing the gas and liquid phase velocities and phase content obtained at the phase level and the density of each component obtained at the component level, and then the equilibrium separation calculation is performed to obtain X. e,i and X e Then, based on the phase transition model proposed above, the program can calculate the phase variables of each component in the gas phase and the overall phase variable of the gas phase. After obtaining these phase variables, the content of each component is updated using the component equation. Finally, based on the various physical property parameter models, the physical property parameters of the gas and liquid phases are updated to prepare for the calculation of the next time step.

[0150] Pipeline network example: The structure of a natural gas condensate gathering and transportation pipeline network is as follows. Figure 8As shown, in this pipeline network, natural gas condensate from two gas wells enters from Node 1 and Node 2 respectively, and is transported to Node 3 via Pipe 1 and Pipe 2. After mixing at Node 3, it is then transported to Node 4 via Pipe 3. The composition of the natural gas condensate produced by the two gas wells is shown in Table 1, the parameters of each pipeline are shown in Table 2, and the operating parameters of the pipeline network are shown in Table 3. It is worth noting that the composition, flow rate, and temperature of the natural gas condensate flowing into the pipeline network from the two nodes, Node 1 and Node 2, are different, thus resulting in a complex mixing process at Node 3. This example was simulated using the method provided in this application, and the results are shown in Table 3. Figures 9 to 20 .

[0151] Table 1 Composition of two types of natural gas condensate

[0152]

[0153] Table 2 Parameters of each pipe in the pipeline network

[0154]

[0155] Table 3 Pipeline network operating parameters

[0156]

[0157] Figure 9 as well as Figure 10 The diagram shows the pressure and temperature distribution along the pipeline, including... Figure 9 The voltage drop calculated by the display program is slightly lower than the actual result, with a difference of about 1 bar. Figure 10 The temperature distribution shown indicates that the temperature results given by the program are very close to the actual results, which shows that the pipeline temperature model established in this application has good accuracy.

[0158] To verify the tracking effect of the components, this application selected two typical components, C1 and H2, and showed their distribution along the pipeline. Figure 11 and Figure 12 The program shows that the C1 density of the gas and liquid phases is very close to the actual result, but there is still a certain difference. This difference is likely due to the different phase equilibrium calculations. Figure 13 and Figure 14 The results for H2 further demonstrate the applicability of the method provided in this application.

[0159] Using flow and component data, this application also analyzes the component conservation of three algorithms in pipeline network calculations. Figure 15 , Figure 16 and Figure 17The mass flow rates of gas phase C1, liquid phase C1, and total C1 are shown respectively. The results show that the transient component tracking method for oil and gas field condensate pipeline networks provided in this application can well ensure the conservation of components. However, the equilibrium points determined by the respective phase equilibrium algorithms are inconsistent, resulting in different flow rates of C1 in each phase. Figure 18 , Figure 19 and Figure 20 The results for another component, H2, are similar to those for C1. It is worth noting that the content of H2 is much lower than that of C1, which indicates that the pipeline component tracking algorithm provided in this application has good applicability and can accurately predict the flow of each component.

[0160] Based on the same inventive concept, this application also provides a transient component tracking device suitable for oil and gas field condensate pipeline networks, which can be used to implement the method described in the above embodiments, as shown in the following embodiments. Since the principle of the transient component tracking device for oil and gas field condensate pipeline networks is similar to that of the transient component tracking method for oil and gas field condensate pipeline networks, the implementation of the transient component tracking device for oil and gas field condensate pipeline networks can refer to the implementation of the transient component tracking method for oil and gas field condensate pipeline networks, and repeated details will not be elaborated further. As used below, the term "unit" or "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0161] The present invention provides a specific implementation of a transient component tracking device suitable for oil and gas field condensate pipeline networks, which enables a transient component tracking method applicable to oil and gas field condensate pipeline networks. See [link to specific implementation details]. Figure 21 The transient component tracking device applicable to oil and gas field condensate pipeline networks specifically includes the following components:

[0162] The component change prediction module 10 is used to predict the component change at any location in the condensate pipeline network based on a pre-established pipeline network control model and the initial components in the condensate pipeline network, wherein the pipeline network control model is used to characterize the component state parameters at any location in the condensate pipeline network.

[0163] The phase change prediction module 20 is used to predict the phase change at each location in the condensate pipeline network based on the component changes.

[0164] In one embodiment, the phase change prediction module includes:

[0165] The equation of state establishment unit is used to establish the gas-liquid phase equation of state of the condensate pipeline network based on the component changes. The gas-liquid phase equation of state is the PR equation of state, which is used to predict the gas-liquid phase distribution of the condensate pipeline network.

[0166] A phase change prediction unit is used to predict the phase change at each location in the condensate pipeline network based on the gas-liquid phase state equation.

[0167] In one embodiment, the transient component tracking device suitable for oil and gas field condensate pipeline networks further includes:

[0168] An iterative update module is used to update the component changes and phase changes according to the gas-liquid phase state equation.

[0169] In one embodiment, the transient component tracking device suitable for oil and gas field condensate pipeline networks further includes:

[0170] A pipeline control model establishment module, used to establish the pipeline control model, the pipeline control model establishment module includes:

[0171] The single-pipe control model establishment unit is used to establish the control model of a single pipe based on the component state parameters at any location within the single pipe.

[0172] The connection point control model establishment unit is used to establish the control model of the connection point based on the component state parameters of the connection point between multiple pipelines.

[0173] The pipeline control model establishment unit is used to establish the pipeline control model based on the control models of multiple pipelines and the control models of multiple connection points, wherein the control models of multiple pipelines correspond to multiple pipelines, and the control models of multiple connection points correspond to multiple connection points.

[0174] In one embodiment, the component state parameters include temperature, pressure, and flow rate.

[0175] As can be seen from the above description, the transient component tracking device for oil and gas field condensate pipeline networks provided in the embodiments of the present invention predicts the component changes at any location in the condensate pipeline network based on a pre-established pipeline network control model and the initial components in the condensate pipeline network. The pipeline network control model is used to characterize the component state parameters at any location in the condensate pipeline network. Then, the phase change at each location in the condensate pipeline network is predicted based on the component changes.

[0176] Based on the established gas-liquid two-phase flow simulation algorithm, this application establishes component equations considering phase changes for both pipelines and connection points. Next, the gas-phase-based phase change model is extended to each component, forming a phase change model for natural gas condensate based on each component. Then, a fluid state equation is introduced to calculate the equilibrium state of each component in real time. Finally, based on the relationship between flow simulation, component calculation, and phase equilibrium flashing, a component tracking algorithm for natural gas condensate pipeline networks is established. This algorithm can dynamically track the composition of the fluid within the pipe and, based on the fluid composition, pressure, and temperature of each pipe section, calculate phase variables and related flow parameters in real time, thus realizing component and phase change tracking of the natural gas condensate pipeline network.

[0177] The embodiments of this application also provide a specific implementation of an electronic device capable of implementing all steps in the transient component tracking method for oil and gas field condensate pipeline networks described in the above embodiments. See [link to relevant documentation]. Figure 22 The electronic devices specifically include the following:

[0178] Processor 1201, memory 1202, communications interface 1203, and bus 1204;

[0179] The processor 1201, memory 1202, and communication interface 1203 communicate with each other via bus 1204; the communication interface 1203 is used to realize information transmission between server-side devices and client-side devices and other related devices.

[0180] The processor 1201 is used to call the deterministic machine program in the memory 1202. When the processor executes the deterministic machine program, it implements all the steps in the transient component tracking method for oil and gas field condensate pipeline networks in the above embodiments. For example, when the processor executes the deterministic machine program, it implements the following steps:

[0181] Step 100: Predict the composition change at any location in the condensate pipeline network based on the pre-established pipeline network control model and the initial composition in the condensate pipeline network, wherein the pipeline network control model is used to characterize the composition state parameters at any location in the condensate pipeline network.

[0182] Step 200: Predict the phase change at each location in the condensate pipeline network based on the component changes.

[0183] Embodiments of this application also provide a deterministic machine-readable storage medium capable of implementing all steps of the transient component tracking method for oil and gas field condensate pipeline networks described in the above embodiments. The deterministic machine-readable storage medium stores a deterministic machine program, which, when executed by a processor, implements all steps of the transient component tracking method for oil and gas field condensate pipeline networks described in the above embodiments. For example, when the processor executes the deterministic machine program, it implements the following steps:

[0184] Step 100: Predict the composition change at any location in the condensate pipeline network based on the pre-established pipeline network control model and the initial composition in the condensate pipeline network, wherein the pipeline network control model is used to characterize the composition state parameters at any location in the condensate pipeline network.

[0185] Step 200: Predict the phase change at each location in the condensate pipeline network based on the component changes.

[0186] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. In particular, hardware + program embodiments are relatively simple in description because they are fundamentally similar to method embodiments; relevant parts can be referred to the descriptions in the method embodiments.

[0187] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0188] While this application provides method operation steps as shown in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-inventive labor. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only execution order. In actual device or client product execution, the method can be executed sequentially as shown in the embodiments or drawings, or in parallel (e.g., in a parallel processor or multi-threaded processing environment).

[0189] For ease of description, the above devices are described in terms of function, divided into various modules. Of course, in implementing the embodiments of this specification, the functions of each module can be implemented in one or more software and / or hardware components, or a module that performs the same function can be implemented by a combination of multiple sub-modules or sub-units. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between devices or units, and may be electrical, mechanical, or other forms.

[0190] Those skilled in the art will also know that, besides implementing the controller using purely deterministic machine-readable program code, the same functions can be achieved by logically programming the method steps, making the controller function as logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers (PLCs), and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the devices within it used to implement various functions can also be considered structures within that hardware component. Alternatively, the devices used to implement various functions can be considered as both software modules implementing the method and structures within a hardware component.

[0191] In a typical configuration, a device is defined as having one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0192] Memory may include forms such as non-persistent storage in machine-readable media, random access memory (RAM), and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of a machine-readable medium.

[0193] The embodiments described in this specification can be described in the general context of deterministic machine executable instructions, such as program modules, executed by a deterministic machine. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. The embodiments of this specification can also be practiced in distributed deterministic environments, where tasks are performed by remote processing devices connected via a communication network. In distributed deterministic environments, program modules can reside in local and remote deterministic machine storage media, including storage devices.

[0194] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, system embodiments are basically similar to method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. In the description of this specification, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments in this specification. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0195] The above description is merely an embodiment of the present specification and is not intended to limit the embodiments of the present specification. For those skilled in the art, various modifications and variations can be made to the embodiments of the present specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the embodiments of the present specification should be included within the scope of the claims of the embodiments of the present specification.

Claims

1. A transient component tracking method applicable to oil and gas field condensate pipeline networks, characterized in that, include: Based on a pre-established pipeline control model and the initial composition within the condensate pipeline network, the composition change at any location within the condensate pipeline network is predicted. The pipeline control model is used to characterize the composition state parameters at any location within the condensate pipeline network. The composition state parameters include the density of each component in the gas phase, the density in the liquid phase, the gas phase flow rate, and the liquid phase flow rate. The phase change at each location in the condensate pipeline is predicted based on the component changes, wherein the phase change includes the mass change of each component from liquid phase to gas phase and the mass change from gas phase to liquid phase. Establishing the pipeline network control model includes the following steps: A gas-liquid two-phase control model for a single pipeline is established based on the component state parameters at any location within the pipeline. A gas-liquid two-phase control model for the connection point is established based on the component state parameters of the connection point between multiple pipelines. The pipeline control model is established based on the control models of multiple pipelines and the control models of multiple connection points, wherein the control model of multiple pipelines corresponds to multiple pipelines and the control model of multiple connection points corresponds to multiple connection points. The process of predicting the component changes and the phase changes also includes: Based on the gas-liquid phase flow rate and phase content obtained at the phase level and the density of each component obtained at the component level, the total composition of the fluid is calculated by summing and equilibrium separation calculation is performed to obtain the equilibrium phase fraction of each component and the overall equilibrium phase fraction. The phase variables of each component in the gas phase and the overall phase variables of the gas phase are calculated based on the equilibrium phase fractions of each component and the overall equilibrium phase fraction. The content of each component is updated using the component equation, and the physical properties of the gas and liquid phases are updated based on the physical property parameter model.

2. The transient component tracking method according to claim 1, characterized in that, Also includes: The component changes are determined based on the gas-liquid phase state equation of the condensate pipeline network, which is used to predict the gas-liquid phase content and physical properties of the condensate pipeline network.

3. The transient component tracking method according to claim 2, characterized in that, Also includes: The composition change and the phase change are updated according to the gas-liquid phase equation of state.

4. The transient component tracking method according to claim 1, characterized in that, The component state parameters include temperature and pressure.

5. A transient component tracking device suitable for oil and gas field condensate pipeline networks, characterized in that, include: The component change prediction module is used to predict the component change at any location in the condensate pipeline network based on a pre-established pipeline network control model and the initial components in the condensate pipeline network. The pipeline network control model is used to characterize the component state parameters at any location in the condensate pipeline network. The component state parameters include the density of each component in the gas phase, the density in the liquid phase, the gas phase flow rate, and the liquid phase flow rate. A phase change prediction module is used to predict the phase change at each location in the condensate pipeline network based on the component changes, wherein the phase change includes the mass change of each component from the liquid phase to the gas phase and the mass change from the gas phase to the liquid phase. A pipeline control model establishment module, used to establish the pipeline control model, the pipeline control model establishment module includes: The single-pipe control model establishment unit is used to establish the control model of a single pipe based on the component state parameters at any location within the single pipe. The connection point control model establishment unit is used to establish the control model of the connection point based on the component state parameters of the connection point between multiple pipelines. The pipeline control model establishment unit is used to establish the pipeline control model based on the control models of multiple pipelines and the control models of multiple connection points, wherein the control models of multiple pipelines correspond to multiple pipelines and the control models of multiple connection points correspond to multiple connection points. The process of predicting the component changes and the phase changes also includes: Based on the gas-liquid phase flow rate and phase content obtained at the phase level and the density of each component obtained at the component level, the total composition of the fluid is calculated by summing and equilibrium separation calculation is performed to obtain the equilibrium phase fraction of each component and the overall equilibrium phase fraction. The phase variables of each component in the gas phase and the overall phase variables of the gas phase are calculated based on the equilibrium phase fractions of each component and the overall equilibrium phase fraction. The content of each component is updated using the component equation, and the physical properties of the gas and liquid phases are updated based on the physical property parameter model.

6. The transient component tracking device according to claim 5, characterized in that, Also includes: The component change determination module is used to determine the component change based on the gas-liquid phase state equation of the condensate pipeline network, which is used to predict the gas-liquid phase distribution of the condensate pipeline network.

7. The transient component tracking device according to claim 6, characterized in that, Also includes: An iterative update module is used to update the component changes and phase changes according to the gas-liquid phase state equation.

8. The transient component tracking device according to claim 5, characterized in that, The component state parameters include temperature and pressure.

9. A computer program product comprising a computer program / instructions, characterized in that, When executed by a processor, the computer program / instruction implements the steps of the transient component tracking method for oil and gas field condensate pipeline networks as described in any one of claims 1 to 4.

10. An electronic device, comprising a memory, a processor, and a deterministic machine program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the transient component tracking method for oil and gas field condensate pipeline networks as described in any one of claims 1 to 4.

11. A deterministic machine-readable storage medium having a deterministic machine program stored thereon, characterized in that, When the determination program is executed by the processor, it implements the steps of the transient component tracking method for oil and gas field condensate pipeline networks as described in any one of claims 1 to 4.

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