Method and device for controlling water addition in an oil gathering pipeline

Abstract

A water mixing amount control method and device for an oilfield gathering pipeline, the method comprising: acquiring crude oil related information of an oilfield region to be controlled; determining a critical wall sticking temperature of a gathering pipeline in the oilfield region to be controlled according to the acquired crude oil related information; and determining a control parameter of a wellhead of the gathering pipeline according to the determined critical wall sticking temperature and a predetermined water mixing amount control model of the gathering pipeline.

Description

Technical Field

[0001] This article relates to the field of oilfield oil and gas gathering and transportation technology, and in particular to a method and device for controlling the amount of water added to oilfield gathering and transportation pipelines. Background Technology

[0002] In oil-water two-phase pipe flow, as the temperature of the oil-water system decreases, the viscosity of the system increases, and the interaction forces between oil droplets and between oil droplets and the wall increase. This cohesion promotes wall adhesion. Under flow conditions, shear stress will hinder the adhesion between oil droplets and the adhesion between oil droplets and the wall, which is unfavorable for wall adhesion.

[0003] The existing methods for testing the wall adhesion temperature of crude oil and the crude oil wall adhesion simulation device (publication number CN112697645A) fully consider the adhesion characteristics of crude oil emulsions with different high water content to the pipe wall surface. The critical wall adhesion temperature under different water content conditions of produced fluids in different oilfield production blocks is measured. Linear or nonlinear regression analysis is used, based on a large amount of experimental data, combined with relevant crude oil physical properties, to establish mathematical models for the critical wall adhesion temperature of different high water content crude oils. However, these existing methods cannot effectively reduce energy consumption. Summary of the Invention

[0004] This application provides a method and apparatus for controlling the water injection volume in an oilfield gathering and transportation pipeline. The method adjusts the control parameters at the wellhead of the gathering and transportation pipeline by determining the critical wall adhesion temperature, so as to reduce energy consumption by adjusting the water injection volume or the water injection temperature.

[0005] This application provides a method for controlling water mixing in oilfield gathering and transportation pipelines, the method comprising:

[0006] Obtain crude oil-related information for the oilfield area to be controlled;

[0007] Determine the critical wall adhesion temperature of the gathering and transportation pipelines in the oilfield area to be controlled based on the obtained crude oil-related information;

[0008] The control parameters for the wellhead of the gathering and transportation pipeline are determined based on the established critical wall adhesion temperature and the predetermined water injection control model for the gathering and transportation pipeline.

[0009] In one exemplary embodiment, determining the critical wall adhesion temperature of the gathering and transportation pipeline in the oilfield area to be controlled based on the acquired crude oil-related information includes:

[0010] Based on the crude oil emulsion pour point temperature, the comprehensive water content in the oil-water suspension, and the shear stress at the pipeline inner wall determined by the crude oil information, the critical wall adhesion temperature of the oilfield gathering and transportation pipeline is determined using the formula for calculating the critical wall adhesion temperature of the pipeline.

[0011] The formula for calculating the critical wall adhesion temperature of the pipeline is as follows:

[0012] T 粘 =T GP -kφ m τ n ;

[0013] Among them, T 粘 T represents the critical wall adhesion temperature of the pipe. GP φ represents the pour point temperature of the crude oil emulsion, φ represents the combined water content in the oil-water suspension, τ represents the shear stress at the inner wall of the pipeline, and k, m, and n represent the fitting parameters of the experimental results.

[0014] In one exemplary embodiment, the shear stress at the inner wall of the pipeline is determined by the following formula:

[0015]

[0016] Where τ represents the shear stress at the inner wall of the pipeline, μ represents the viscosity of crude oil, v represents the average flow velocity of the fluid in the pipeline, and D represents the inner diameter of the pipeline.

[0017] In one exemplary embodiment, the control parameters of the wellhead include:

[0018] The water injection flow rate and / or water injection temperature at the wellhead of the gathering and transportation pipeline.

[0019] In one exemplary embodiment, determining the control parameters at the wellhead of the gathering and transportation pipeline based on the determined critical wall adhesion temperature and a predetermined water injection control model for the gathering and transportation pipeline includes:

[0020] Determine and obtain the relevant parameters for the water mixing flow rate;

[0021] Based on the determined critical wall adhesion temperature and the relevant parameters of the water injection flow rate, the water injection flow rate at the wellhead of the gathering and transportation pipeline is determined using the water injection flow rate calculation formula for the gathering and transportation pipeline.

[0022] The formula for calculating the water mixing flow rate in the gathering and transportation pipeline is as follows:

[0023]

[0024] Among them, T H T represents the temperature of the mixture after water is added to the gathering and transportation pipeline. G Indicates the ambient temperature of the gathering and transportation pipeline installation, T K The inlet temperature of the gathering and transportation pipeline is represented by K, the pipeline number is represented by π, and the outer diameter of the gathering and transportation pipeline is represented by D. i This indicates the total flow rate of the produced fluid at the wellhead. C0 represents the water cut of the produced fluid at the wellhead, C0 represents the specific heat capacity of the crude oil, and G represents the specific heat capacity of the crude oil.w C represents the water mixing flow rate in the gathering and transportation pipeline. w The value represents the specific heat capacity of water, and L represents the length of the gathering and transportation pipeline.

[0025] In one exemplary embodiment, the relevant parameters of the water mixing flow rate include:

[0026] The ambient temperature of the gathering and transportation pipeline, the temperature at the pipeline entrance, the outer diameter of the gathering and transportation pipeline, the total flow rate of the produced fluid at the wellhead, the water content of the produced fluid at the wellhead, the specific heat capacity of crude oil, the specific heat capacity of water, and the length of the gathering and transportation pipeline.

[0027] In one exemplary embodiment, the inlet temperature of the gathering and transportation pipeline is the temperature obtained by adding a preset temperature value to the critical wall adhesion temperature of the pipeline.

[0028] In one exemplary embodiment, determining the wellhead control parameters based on the determined critical wall adhesion temperature of the pipeline and the predetermined water injection control model for the gathering and transportation pipeline includes:

[0029] The relevant parameters for the water mixing temperature were determined and obtained;

[0030] Based on the determined critical wall adhesion temperature and the relevant parameters of the water injection temperature, the water injection temperature at the wellhead of the gathering and transportation pipeline is determined using the calculation formula for the water injection temperature of the gathering and transportation pipeline.

[0031] The formula for calculating the water mixing temperature at the wellhead of the gathering and transportation pipeline is as follows:

[0032]

[0033] Among them, T H G represents the temperature of the mixture after water is added to the gathering and transportation pipeline. i This indicates the total flow rate of the produced fluid at the wellhead. G represents the water content of the produced fluid at the wellhead. w The flow rate of the mixed water in the gathering and transportation pipeline is represented by T0, the initial temperature of the crude oil is represented by C0, and the specific heat capacity of the crude oil is represented by C. w T represents the specific heat capacity of water. w This indicates the water mixing temperature in the gathering and transportation pipeline.

[0034] In one exemplary embodiment, the relevant parameters of the water mixing temperature include: the temperature of the mixed liquid after water mixing in the gathering and transportation pipeline, the total flow rate of the produced fluid at the wellhead, the water content of the produced fluid at the wellhead, the water mixing flow rate in the gathering and transportation pipeline, the initial temperature of the crude oil, the specific heat capacity of the crude oil, and the specific heat capacity of water.

[0035] This application also provides a device for controlling the water mixing volume in an oilfield gathering and transportation pipeline, comprising: a memory and a processor;

[0036] The memory is used to store the program for controlling the water mixing amount in oilfield gathering and transportation pipelines;

[0037] The processor is used to read and execute the program for controlling the water content in oilfield gathering and transportation pipelines, and to perform the method for controlling the water content in oilfield gathering and transportation pipelines as described in any of the above embodiments.

[0038] Compared with related technologies, this application provides a method for controlling the water injection rate in oilfield gathering and transportation pipelines. The method includes: acquiring crude oil-related information about the oilfield area to be controlled; determining the critical wall adhesion temperature of the gathering and transportation pipeline in the oilfield area to be controlled based on the acquired crude oil-related information; and determining the control parameters of the gathering and transportation pipeline wellhead based on the determined critical wall adhesion temperature and a predetermined water injection rate control model. Through the technical solution of this invention, this method further adjusts the control parameters of the gathering and transportation pipeline wellhead by determining the critical wall adhesion temperature, thereby reducing energy consumption by adjusting the water injection rate or the water injection temperature.

[0039] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. Other advantages of this application can be realized and obtained by means of the solutions described in the description and the accompanying drawings. Attached Figure Description

[0040] The accompanying drawings are used to provide an understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0041] Figure 1 This is a flowchart of the water mixing control method for oilfield gathering and transportation pipelines according to an embodiment of this application;

[0042] Figure 2 This is a schematic diagram of a water mixing control device for oilfield gathering and transportation pipelines according to an embodiment of this application;

[0043] Figure 3 This is a flowchart of a water mixing method for oilfield gathering and transportation pipelines in some exemplary embodiments. Detailed Implementation

[0044] This application describes several embodiments, but these descriptions are exemplary and not restrictive, and it will be apparent to those skilled in the art that many more embodiments and implementations are possible within the scope of the embodiments described herein. Although many possible combinations of features are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with, or may replace, any feature or element of any other embodiment.

[0045] This application includes and contemplates combinations of features and elements known to those skilled in the art. The embodiments, features, and elements disclosed in this application may also be combined with any conventional features or elements to form a unique inventive scheme as defined by the claims. Any feature or element of any embodiment may also be combined with features or elements from other inventive schemes to form another unique inventive scheme as defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in this application may be implemented individually or in any suitable combination. Therefore, the embodiments are not limited except by the limitations imposed by the appended claims and their equivalents. Furthermore, various modifications and changes may be made within the scope of the appended claims.

[0046] Furthermore, in describing representative embodiments, the specification may have presented methods and / or processes as a specific sequence of steps. However, the method or process should not be limited to the specific order of steps described herein, to the extent that it does not depend on such a specific order. As will be understood by those skilled in the art, other sequences of steps are also possible. Therefore, the specific order of steps set forth in the specification should not be construed as a limitation of the claims. Moreover, the claims concerning the method and / or process should not be limited to the steps performed in the written order, and those skilled in the art will readily understand that these orders can be varied and still remain within the spirit and scope of the embodiments of this application.

[0047] In oil-water two-phase pipe flow, as the system temperature decreases, the system viscosity increases, leading to increased interaction forces between oil droplets and between droplets and the pipe wall. This cohesion promotes wall adhesion. Under flow conditions, shear stress hinders adhesion between droplets and between droplets and the pipe wall, thus inhibiting wall adhesion. When the resistance and cohesion reach equilibrium, a large number of droplets adhere to the pipe wall; this temperature is the critical wall adhesion temperature. Below the critical wall adhesion temperature, pipe blockage is likely; above it, blockage is generally not a concern. Furthermore, in high water-cut stages, the critical wall adhesion temperature is generally lower than the pour point of crude oil.

[0048] Based on the above theory of freezing point adhesion to the wall, it can be concluded that by using the critical adhesion temperature as the control temperature and amount of water added, the gathering and transportation temperature and energy consumption will be further reduced.

[0049] Based on this theory, this application proposes a method for controlling the water mixing volume in oilfield gathering and transportation pipelines, the details of which are as follows.

[0050] This disclosure provides a method for controlling the water mixing amount in oilfield gathering and transportation pipelines, such as... Figure 1 As shown, the method includes steps S100-S120, as detailed below:

[0051] S100. Obtain crude oil-related information for the oilfield area to be controlled;

[0052] S110. Determine the critical wall adhesion temperature of the gathering and transportation pipeline in the oilfield area to be controlled based on the obtained crude oil-related information;

[0053] S120. Determine the control parameters of the wellhead of the gathering and transportation pipeline based on the determined critical wall adhesion temperature and the predetermined water injection control model of the gathering and transportation pipeline.

[0054] In this embodiment, crude oil-related information includes: basic physical properties of crude oil, crude oil production volume, crude oil water cut, and crude oil gathering temperature; the meaning of each piece of information is as follows:

[0055] Basic physical properties of crude oil: Since wells in the same block are at roughly the same depth, the water cut of the crude oil emulsion portion in the produced fluid will remain within a relatively stable range. The pour point, viscosity, and composition of the crude oil emulsion affect crude oil adhesion to the well walls; higher pour points, greater viscosity, and higher levels of asphaltenes and gums in the crude oil all contribute to adhesion to the walls. The greater the difference between the gathering and transportation temperature and the pour point of the crude oil emulsion, the more likely adhesion will occur.

[0056] Crude oil production: When the production of the oil well is greater, the flow rate of the production medium in the gathering and transportation pipeline is faster, the shear stress on the pipeline wall is greater, that is, the scouring intensity is stronger, and the crude oil is less likely to stick to the wall; conversely, the crude oil is more likely to stick to the wall.

[0057] Crude oil water content: The higher the water content of the oil well's produced fluid, the better it is for the flow of the produced fluid medium in the pipeline. When the water content is high, a water film will form on the inner wall of the pipeline, thereby reducing the chance of crude oil contacting the inner wall and making it less likely to stick to the wall; conversely, crude oil is more likely to stick to the wall.

[0058] Crude oil gathering temperature: Under conditions where the pipeline is not corroded or exposed, a stable temperature field will form around the pipeline. When the gathering temperature is higher than the pour point of the crude oil emulsion, wall adhesion will not occur; when the gathering temperature drops below the pour point of the crude oil emulsion, the crude oil emulsion droplets in the produced fluid begin to flocculate, making crude oil wall adhesion more likely.

[0059] In one exemplary embodiment, determining the critical wall adhesion temperature of the gathering and transportation pipeline in the oilfield area to be controlled based on the acquired crude oil-related information includes:

[0060] Based on the crude oil emulsion pour point temperature, the comprehensive water content in the oil-water suspension, and the shear stress at the pipeline inner wall determined by the crude oil information, the critical wall adhesion temperature of the oilfield gathering and transportation pipeline is determined using the formula for calculating the critical wall adhesion temperature of the pipeline.

[0061] The formula for calculating the critical wall adhesion temperature of the pipeline is as follows:

[0062] T 粘 =T GP -kφ m τ n ;

[0063] Among them, T 粘 This indicates the critical wall adhesion temperature of the pipeline, measured in °C (°C); T GP The crude oil emulsion pour point temperature is expressed in °C. This parameter can be determined using existing conventional methods and is not specifically limited here. φ represents the overall water content in the oil-water suspension, ranging from 70% to 100%. τ represents the shear stress at the inner wall of the pipeline, expressed in Pa. k, m, and n represent the fitting parameters for the experimental results. In the embodiments of this application, k, m, and n represent the fitting parameters for the experimental results, which can be determined through multiple experiments; the crude oil emulsion pour point temperature and the overall water content in the oil-water suspension are obtained by detection instruments.

[0064] In one exemplary embodiment, the shear stress at the inner wall of the pipeline is determined by the following formula:

[0065]

[0066] Where τ represents the shear stress at the inner wall of the pipeline, μ represents the viscosity of crude oil in mPa·s, which can be measured; v represents the average flow velocity of the fluid in the pipeline in m / s, which can be measured; and D represents the inner diameter of the pipeline in meters, which can be measured.

[0067] In one exemplary embodiment, the control parameters of the wellhead include: the water injection flow rate and / or the water injection temperature at the wellhead of the gathering and transportation pipeline.

[0068] In one exemplary embodiment, the control parameters for the wellhead of the gathering and transportation pipeline are determined based on the determined critical wall adhesion temperature and a predetermined water injection control model for the gathering and transportation pipeline, including:

[0069] Determine and obtain the relevant parameters for the water mixing flow rate;

[0070] Based on the determined critical wall adhesion temperature and the relevant parameters of the water injection flow rate, the water injection flow rate at the wellhead of the gathering and transportation pipeline is determined using the water injection flow rate calculation formula for the gathering and transportation pipeline.

[0071] The formula for calculating the water mixing flow rate in the gathering and transportation pipeline is as follows:

[0072]

[0073] Among them, T HThis indicates the temperature of the mixture after water is added to the gathering and transportation pipeline, in °C (°C); T G This indicates the ambient temperature during the laying of the gathering and transportation pipeline, in °C; T K This indicates the inlet temperature of the gathering and transportation pipeline, in °C. K represents the pipeline number; π represents pi; D represents the outer diameter of the gathering and transportation pipeline, in meters (m); G... i This indicates the total flow rate of the produced fluid at the wellhead, expressed in kg / h. The wellhead produced fluid water content is expressed as a percentage (%); C0 represents the specific heat capacity of crude oil, expressed as J / kg·℃; G w The C indicates the water mixing flow rate in the gathering and transportation pipeline, expressed in kg / h. w The value represents the specific heat capacity of water, measured in J / kg·℃; L represents the length of the gathering and transportation pipeline, measured in meters.

[0074] In one exemplary embodiment, the relevant parameters of the water mixing flow rate include:

[0075] The ambient temperature of the gathering and transportation pipeline, the temperature at the pipeline entrance, the outer diameter of the gathering and transportation pipeline, the total flow rate of the produced fluid at the wellhead, the water content of the produced fluid at the wellhead, the specific heat capacity of crude oil, the specific heat capacity of water, and the length of the gathering and transportation pipeline.

[0076] In one exemplary embodiment, the inlet temperature of the gathering and transportation pipeline is the temperature obtained by adding a preset temperature value to the critical wall-adhesion temperature of the pipeline. The inlet / outlet temperature of the gathering and transportation pipeline is taken as the critical wall-adhesion temperature T. 粘 The above 2℃ is in °C.

[0077] In this embodiment of the application, the ambient temperature of the gathering and transportation pipeline, the inlet temperature of the gathering and transportation pipeline, the outer diameter of the gathering and transportation pipeline, the total flow rate of the produced fluid at the wellhead, the water content of the produced fluid at the wellhead, the specific heat capacity of crude oil, the specific heat capacity of water, and the length of the gathering and transportation pipeline are measured by a detection instrument. Based on the above parameters measured, and combined with the calculation formula for the water mixing flow rate of the gathering and transportation pipeline, the water mixing flow rate of the gathering and transportation pipeline is calculated.

[0078] In one exemplary embodiment, determining the wellhead control parameters based on the determined critical wall adhesion temperature of the pipeline and the predetermined water injection control model for the gathering and transportation pipeline includes: determining and obtaining relevant parameters of the water injection temperature; determining the water injection temperature at the wellhead of the gathering and transportation pipeline using the water injection temperature calculation formula for the gathering and transportation pipeline based on the determined critical wall adhesion temperature and the relevant parameters of the water injection temperature; wherein, the water injection temperature calculation formula for the wellhead of the gathering and transportation pipeline is:

[0079]

[0080] Among them, T H G represents the temperature of the mixture after water is added to the gathering and transportation pipeline. i This indicates the total flow rate of the produced fluid at the wellhead. G represents the water content of the produced fluid at the wellhead.w The flow rate of the mixed water in the gathering and transportation pipeline is represented by T0, the initial temperature of the crude oil is represented by C0, and the specific heat capacity of the crude oil is represented by C. w T represents the specific heat capacity of water. w This indicates the water mixing temperature in the gathering and transportation pipeline.

[0081] In one exemplary embodiment, the relevant parameters of the water mixing temperature include: the temperature of the mixed liquid after water mixing in the gathering and transportation pipeline, the total flow rate of the produced fluid at the wellhead, the water content of the produced fluid at the wellhead, the water mixing flow rate in the gathering and transportation pipeline, the initial temperature of the crude oil, the specific heat capacity of the crude oil, and the specific heat capacity of water.

[0082] This disclosure also provides a device for controlling the water mixing volume in oilfield gathering and transportation pipelines, such as... Figure 2 As shown, the device includes: a memory 210 and a processor 220;

[0083] The memory 210 is used to store the program for controlling the water mixing amount in oilfield gathering and transportation pipelines;

[0084] The processor 220 is used to read and execute the program for controlling the water content in oilfield gathering and transportation pipelines, and to perform the method for controlling the water content in oilfield gathering and transportation pipelines as described in any of the above embodiments.

[0085] The following example illustrates the method for controlling water mixing in oilfield gathering and transportation pipelines, such as... Figure 3 As shown:

[0086] Step 301: Obtain crude oil-related information for the oilfield area to be controlled;

[0087] Crude oil-related information includes: basic physical properties of crude oil, crude oil production volume, crude oil water content, and crude oil gathering temperature.

[0088] Step 302: Determine the shear stress at the inner wall of the pipeline based on relevant crude oil information;

[0089] The shear stress at the inner wall of the pipeline is determined by the following formula:

[0090]

[0091] Where τ represents the shear stress at the inner wall of the pipeline, μ represents the viscosity of crude oil, v represents the average flow velocity of the fluid in the pipeline, and D represents the inner diameter of the pipeline.

[0092] Step 303: Based on the crude oil emulsion pour point temperature, the comprehensive water content in the oil-water suspension, and the shear stress at the inner wall of the pipeline determined by the crude oil information, the critical wall adhesion temperature of the oilfield gathering and transportation pipeline is determined using the formula for calculating the critical wall adhesion temperature of the pipeline.

[0093] The formula for calculating the critical wall adhesion temperature of the pipeline is as follows:

[0094] T 粘 =T GP -kφ m τ n ;

[0095] Among them, T 粘 T represents the critical wall adhesion temperature of the pipe. GP φ represents the pour point temperature of the crude oil emulsion, φ represents the combined water content in the oil-water suspension, τ represents the shear stress at the inner wall of the pipeline, and k, m, and n represent the fitting parameters of the experimental results.

[0096] Step 304: Determine the control parameters of the wellhead of the gathering and transportation pipeline based on the determined critical wall adhesion temperature and the predetermined water injection control model of the gathering and transportation pipeline.

[0097] In step 3041, the relevant parameters of the water injection flow rate are determined and obtained; and based on the determined critical wall adhesion temperature and the relevant parameters of the water injection flow rate, the water injection flow rate at the wellhead of the gathering and transportation pipeline is determined using the water injection flow rate calculation formula for the gathering and transportation pipeline.

[0098] The formula for calculating the water mixing flow rate in the gathering and transportation pipeline is as follows:

[0099]

[0100] Among them, T H T represents the temperature of the mixture after water is added to the gathering and transportation pipeline. G Indicates the ambient temperature of the gathering and transportation pipeline laying, T K The inlet temperature of the gathering and transportation pipeline is represented by K, the pipeline number is represented by π, and the outer diameter of the gathering and transportation pipeline is represented by D. i This indicates the total flow rate of the produced fluid at the wellhead. C0 represents the water cut of the produced fluid at the wellhead, C0 represents the specific heat capacity of the crude oil, and G represents the specific heat capacity of the crude oil. w C represents the water mixing flow rate in the gathering and transportation pipeline. w The value represents the specific heat capacity of water, and L represents the length of the gathering and transportation pipeline.

[0101] In step 3042, the relevant parameters of the water mixing temperature are determined and obtained; and based on the determined critical wall adhesion temperature and the relevant parameters of the water mixing temperature, the water mixing temperature at the wellhead of the gathering and transportation pipeline is determined using the water mixing temperature calculation formula for the gathering and transportation pipeline.

[0102] The formula for calculating the water mixing temperature at the wellhead of the gathering and transportation pipeline is as follows:

[0103]

[0104] Among them, T H G represents the temperature of the mixture after water is added to the gathering and transportation pipeline. iThis indicates the total flow rate of the produced fluid at the wellhead. G represents the water content of the produced fluid at the wellhead. w The flow rate of the mixed water in the gathering and transportation pipeline is represented by T0, the initial temperature of the crude oil is represented by C0, and the specific heat capacity of the crude oil is represented by C. w T represents the specific heat capacity of water. w This indicates the water mixing temperature in the gathering and transportation pipeline.

[0105] Step 305: The PLC control system controls the electric regulating valve based on the calculated water mixing flow rate and / or water mixing temperature.

[0106] In step 305, the water mixing flow rate and water mixing temperature of the gathering and transportation pipeline are input into the PLC control system. The PLC control system controls the electric regulating valve according to the calculated water mixing flow rate and / or water mixing temperature to achieve the purpose of real-time control and optimization of water mixing.

[0107] The specific implementation includes the following three cases:

[0108] When the control system in the oilfield area to be controlled can only adjust the water injection flow rate and the water injection temperature is fixed, the water injection flow rate of the gathering and transportation pipeline is calculated in step 3041.

[0109] When the control system in the oilfield area to be controlled can only adjust the water injection temperature and the water injection flow rate is fixed, the water injection temperature of the gathering and transportation pipeline calculated in step 3042 is used.

[0110] When the control system in the oilfield area to be controlled can adjust not only the water injection flow rate but also the water injection temperature, the water injection flow rate and water injection temperature of the gathering and transportation pipeline are calculated according to steps 3041 and 3042.

[0111] Meanwhile, this invention provides a method for controlling the amount of water added. A PLC control system collects data on flow rate, temperature, pressure, and water content of the wellhead gathering and transportation pipeline. Based on the oil-water specific heat, water addition temperature, and the mathematical model of the critical wall adhesion temperature provided by this method, the electric regulating control valve of the water addition pipeline leading to the wellhead is controlled to ensure that the temperature of the oil-water mixture entering the station after water addition is maintained at 2°C above the critical wall adhesion temperature.

[0112] The embodiments of this application, through the above-described method for controlling the water mixing volume in oilfield gathering and transportation pipelines, can achieve the following technical effects:

[0113] First, by determining the critical wall-sticking temperature, and based on this, determining the water mixing temperature and flow rate for gathering and transportation, energy consumption can be reduced.

[0114] Secondly, high-precision, high-response, and multi-parameter control can be achieved by adjusting the water temperature and / or water flow rate in the control system.

[0115] It will be understood by those skilled in the art that all or some of the steps, systems, or apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

Claims

1. A method for controlling water mixing in oilfield gathering and transportation pipelines, characterized in that, The method includes: Obtain crude oil-related information for the oilfield area to be controlled; Based on the crude oil emulsion pour point temperature, the comprehensive water content in the oil-water suspension, and the shear stress at the pipeline inner wall determined by the crude oil information, the critical wall adhesion temperature of the oilfield gathering and transportation pipeline is determined using the formula for calculating the critical wall adhesion temperature of the pipeline. The formula for calculating the critical wall adhesion temperature of the pipeline is as follows: ； in, This indicates the critical wall adhesion temperature of the pipe. This indicates the pour point temperature of the crude oil emulsion. Indicates the overall water content in an oil-water suspension. This represents the shear stress at the inner wall of the pipeline. Indicates the fitting parameters of the experimental results; Based on the determined critical wall adhesion temperature and the predetermined water injection control model for the gathering and transportation pipeline, the water injection flow rate and water injection temperature at the wellhead of the gathering and transportation pipeline are determined, including: Determine and obtain the relevant parameters for the water mixing flow rate; Based on the determined critical wall adhesion temperature and the relevant parameters of the water injection flow rate, the water injection flow rate at the wellhead of the gathering and transportation pipeline is determined using the water injection flow rate calculation formula for the gathering and transportation pipeline. The formula for calculating the water mixing flow rate in the gathering and transportation pipeline is as follows: ； in, This indicates the temperature of the mixture after water is added to the gathering and transportation pipeline. This indicates the ambient temperature at which the gathering and transportation pipeline is laid. Indicates the inlet temperature of the gathering and transportation pipeline. Indicates the number of the gathering and transportation pipeline. Represents pi (π). Indicates the outer diameter of the gathering and transportation pipeline. This indicates the total flow rate of the produced fluid at the wellhead. Indicates the water content of the produced fluid at the wellhead. Indicates the specific heat capacity of crude oil. This indicates the water mixing flow rate in the gathering and transportation pipeline. This indicates the specific heat capacity of water. Indicates the length of the gathering and transportation pipeline; The relevant parameters for the water mixing temperature were determined and obtained; Based on the determined critical wall adhesion temperature and the relevant parameters of the water injection temperature, the water injection temperature at the wellhead of the gathering and transportation pipeline is determined using the calculation formula for the water injection temperature of the gathering and transportation pipeline. The formula for calculating the water mixing temperature at the wellhead of the gathering and transportation pipeline is as follows: ； in, This indicates the temperature of the mixture after water is added to the gathering and transportation pipeline. This indicates the total flow rate of the produced fluid at the wellhead. Indicates the water content of the produced fluid at the wellhead. This indicates the water mixing flow rate in the gathering and transportation pipeline. Indicates the initial temperature of the crude oil. Indicates the specific heat capacity of crude oil. This indicates the specific heat capacity of water. This indicates the water mixing temperature in the gathering and transportation pipeline.

2. The method for controlling water mixing in oilfield gathering and transportation pipelines according to claim 1, characterized in that, The shear stress at the inner wall of the pipeline is determined by the following formula: in, This represents the shear stress at the inner wall of the pipeline. Indicates crude oil viscosity. This indicates the average flow velocity of the fluid within the pipe. Indicates the inner diameter of the pipe.

3. The method for controlling water mixing in oilfield gathering and transportation pipelines according to claim 1, characterized in that, The relevant parameters for the water mixing flow rate include: The ambient temperature of the gathering and transportation pipeline, the temperature at the pipeline entrance, the outer diameter of the gathering and transportation pipeline, the total flow rate of the produced fluid at the wellhead, the water content of the produced fluid at the wellhead, the specific heat capacity of crude oil, the specific heat capacity of water, and the length of the gathering and transportation pipeline.

4. The method for controlling water mixing in oilfield gathering and transportation pipelines according to claim 3, characterized in that, The inlet temperature of the gathering and transportation pipeline is the temperature obtained by adding a preset temperature value to the critical wall adhesion temperature of the pipeline.

5. The method for controlling water mixing in oilfield gathering and transportation pipelines according to claim 1, characterized in that, The relevant parameters for the water mixing temperature include: the temperature of the mixed liquid after water mixing in the gathering and transportation pipeline, the total flow rate of the produced fluid at the wellhead, the water content of the produced fluid at the wellhead, the water mixing flow rate in the gathering and transportation pipeline, the initial temperature of the crude oil, the specific heat capacity of the crude oil, and the specific heat capacity of water.

6. A device for controlling the amount of water added to an oilfield gathering and transportation pipeline, characterized in that, include: Memory and processor; The memory is used to store the program for controlling the water mixing amount in oilfield gathering and transportation pipelines; The processor is used to read and execute the program for controlling the water content in oilfield gathering and transportation pipelines, and to perform the method for controlling the water content in oilfield gathering and transportation pipelines as described in any one of claims 1-5.

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