Gathering and transportation method and system for oil field produced liquid with extra-high water content and electronic equipment

Abstract

The invention provides a gathering and transportation method and system for oil field produced liquid with ultra-high water content and electronic equipment. The method comprises the steps that the target gathering and transportation temperature of the oil field produced liquid is set to be larger than the critical gathering and transportation temperature of the oil field produced liquid and smaller than the critical wall sticking temperature of the oil field produced liquid; the critical gathering and transportation temperature of the oil field produced liquid is the gathering and transportation temperature when the adhesion acting force of a wall-adhering oil condensing section formed by accumulating wall-adhering water-containing condensate oil generated in the gathering and transportation process of the oil field produced liquid along the oil gathering pipeline on the pipe wall of the oil gathering pipeline is equal to the jacking and extruding acting force of pressure difference generated by the oil field produced liquid on the wall-adhering oil condensing section. According to the scheme provided by the invention, the critical gathering and transportation temperature at which the ultra-high water content crude oil can be safely gathered and transported under the condition that the temperature is lower than the critical wall sticking temperature can be conveniently and accurately determined. Therefore, the energy consumption of the oil field can be further reduced under the condition of ensuring safe gathering and transportation.

Description

Technical Field

[0001] The present invention relates to, but is not limited to, the field of oilfield gathering and transportation, and in particular to, but is not limited to, a method, system and electronic equipment for gathering and transportation of oilfield produced fluid with extremely high water content. Background Art

[0002] In the process of collecting and transporting oilfield produced fluid, the oil gathering system usually adopts heating or water mixing measures to avoid serious oil condensation and wall adhesion during the collection and transportation of oilfield produced fluid, which will block the oil gathering pipeline. Heating the oilfield produced fluid will greatly increase the energy consumption of the oil gathering system and increase production costs.

[0003] Related research and experiments have shown that the operation conditions of oilfield produced fluids with different water contents in the gathering and transportation pipelines are different, and the resulting condensation and wall sticking phenomenon has different effects on the gathering and transportation process. For oilfield produced fluids with extremely high water content, the oilfield produced fluids can be safely gathered and transported at lower temperatures. For example, for oilfield produced fluids with relatively high water content, the "critical wall sticking temperature" can be used instead of the condensation point of the oilfield produced fluid as the boundary condition for safe gathering and transportation. The critical wall sticking temperature refers to the temperature at which the wall sticking rate of the oilfield produced fluid increases sharply as the oil collection temperature decreases. If the temperature continues to decrease, a large number of oil droplets will adhere to the pipe wall, and the wellhead back pressure will increase significantly. However, in the related technology, there is still a lack of in-depth research on the operation of extremely high water content crude oil in the pipeline at the critical wall sticking temperature.

[0004] Therefore, how to further reduce oil field energy consumption while ensuring safe gathering and transportation is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0006] In order to accurately and reasonably determine the oil gathering temperature boundary below the critical wall sticking temperature of waxy crude oil under extremely high water content conditions, the present invention innovatively proposes a method for calculating the critical gathering temperature boundary by achieving force balance through the pressure difference squeezing force of the oil gathering pipeline and the adhesion force of the condensate section on the pipe wall, so as to quantify the oil gathering temperature. The critical gathering temperature boundary calculation method provided by the present invention has the advantages of being accurate and convenient, and can further reduce the gathering temperature below the wall sticking temperature, thereby achieving further energy saving and consumption reduction in the oil field.

[0007] The oil collection temperature can be further reduced below the wall sticking temperature, thus achieving energy conservation and consumption reduction in the oil field.

[0008] The present disclosure provides a method for collecting and transporting oilfield produced fluid with extremely high water content, the method comprising:

[0009] The target gathering and transportation temperature of the oilfield produced fluid is set to be greater than the critical gathering and transportation temperature of the oilfield produced fluid and less than the critical wall adhesion temperature of the oilfield produced fluid;

[0010] The critical gathering and transportation temperature of the oilfield produced fluid is: the gathering and transportation temperature at which the adhesion force of the sticky wall condensed oil section formed by the accumulation of sticky wall water-containing condensed oil generated in the process of gathering and transportation of the oilfield produced fluid along the oil gathering pipeline to the pipe wall of the oil gathering pipeline is equal to the squeezing force of the pressure difference generated by the oilfield produced fluid on the sticky wall condensed oil section.

[0011] In some embodiments provided in the present disclosure, the method for obtaining the critical gathering and transportation temperature T1 comprises the following steps:

[0012] Get the following parameters:

[0013] The maximum allowable back pressure P0 of the oilfield produced fluid at the starting point of the oil gathering pipeline, the inner radius R of the oil gathering pipeline, the density ρ of the oilfield produced fluid, the dynamic viscosity μ of the oilfield produced fluid, the flow rate v of the oilfield produced fluid in the oil gathering pipeline, the inlet pressure P1 of the oilfield produced fluid at the end of the oil gathering pipeline, the comprehensive water content φ of the oilfield produced fluid, and the emulsified water content of the oilfield produced fluid The length of the oil gathering pipeline from the wellhead to the inlet is L, and the freezing point T of the oil field produced fluid is GP , the wall temperature of the oil gathering pipeline is T w , the temperature of the medium around the oil gathering pipeline T0, the absolute equivalent roughness e, the heat transfer coefficient K of the oil gathering pipeline, the outer diameter D of the oil gathering pipeline, the mass flow rate G of the oil field produced liquid, the specific heat capacity c of the oil field produced liquid at the average oil gathering temperature, the gathering and transportation time t, the initial shear stress τ0 at the wall of the oil gathering pipeline, and the kinematic viscosity ω of the produced liquid;

[0014] The above parameters can be categorized as:

[0015] (1) Physical properties of oilfield produced fluid: density ρ of oilfield produced fluid, dynamic viscosity μ of oilfield produced fluid, flow rate v of oilfield produced fluid in the oil gathering pipeline, comprehensive water content φ of oilfield produced fluid, emulsified water content of oilfield produced fluid The pour point T of oilfield produced fluid GP , the specific heat capacity c of the oilfield produced fluid at the average oil collection temperature, and the kinematic viscosity ω of the oilfield produced fluid.

[0016] (2) Specification parameters of the oil gathering pipeline: inner radius R of the oil gathering pipeline, outer diameter D of the oil gathering pipeline, absolute equivalent roughness e, length L of the oil gathering pipeline from the wellhead to the inlet, and heat transfer coefficient K of the oil gathering pipeline.

[0017] (3) Operation parameters: the maximum allowable back pressure P0 of the oilfield produced fluid at the starting point of the oil gathering pipeline, the inlet pressure P1 of the oilfield produced fluid at the end of the oil gathering pipeline, the mass flow rate G of the oilfield produced fluid, the gathering and transportation time t, the initial shear stress τ0 at the wall of the oil gathering pipeline, the wall temperature T of the oil gathering pipeline w , the temperature T0 of the medium around the oil gathering pipeline.

[0018] The critical gathering temperature T1 is calculated according to formula (1):

[0019]

[0020] In formula (1), P0 is the maximum allowable back pressure of the oilfield produced fluid at the starting point of the oil gathering pipeline, in Pa; λ is the hydraulic friction coefficient, dimensionless; L1 is the distance from the wellhead starting point where the temperature along the way drops to the wall temperature, in m; R is the inner radius of the oil gathering pipeline, in m; ρ is the density of the oilfield produced fluid, in kg / m 3 ; v is the flow rate of the oilfield produced fluid in the oil gathering pipeline, in m / s; P1 is the inlet pressure of the oilfield produced fluid at the end of the oil gathering pipeline, in Pa; δ is the wall thickness of the sticky wall condensation section, in m; φ is the comprehensive water content of the oilfield produced fluid, %; is the emulsified water content of the oilfield produced fluid, %;

[0021] In formula (1), the f -1 (F1) is the inverse function of F1=f(T1), and the original function F1=f(T1) is shown in formula (2):

[0022]

[0023] In formula (2), R is the inner radius of the oil gathering pipeline, in meters; φ is the comprehensive water content of the produced fluid in the oil field, in %; is the emulsified water content of the oilfield produced fluid, %; L1 is the distance from the wellhead starting point where the temperature drops to the wall-adhering temperature, in m; L2 is the distance from the end of the pipeline where the temperature drops to the wall-adhering temperature, in m (L2 = L-L1); L is the length of the oil gathering pipeline from the wellhead to the inlet, in m; T0 is the temperature of the medium surrounding the oil gathering pipeline, in ℃; ψ is the axial heat dissipation parameter of the oil gathering pipeline, in m -1 ; l is the distance between the micro-element segment of the oil-gathering pipeline dl and the starting point of the pipeline, in m; the oil temperature on the micro-element segment of the oil-gathering pipeline dl is T, in °C; a and b are fitting parameters, determined by experiments;

[0024] Formula (2) F1 is a function of T1, and formula (1) is the inverse function of formula (2). When using formula (1), F1 in formula (1) is calculated using formula (1.1);

[0025]

[0026] In formula (1.1), P0 is the maximum allowable back pressure of the oilfield produced fluid at the starting point of the oil gathering pipeline, in Pa; λ is the hydraulic friction coefficient, dimensionless; L1 is the distance from the wellhead starting point where the temperature along the way drops to the wall temperature, in m; R is the inner radius of the oil gathering pipeline, in m; ρ is the density of the oilfield produced fluid, in kg / m 3 ; v is the flow rate of the oilfield produced fluid in the oil gathering pipeline, in m / s; P1 is the inlet pressure of the oilfield produced fluid at the end of the oil gathering pipeline, in Pa; δ is the wall thickness of the sticky wall condensation section, in m; φ is the comprehensive water content of the oilfield produced fluid, %; is the emulsified water content of the oilfield produced fluid, %.

[0027] In formula (1), the distance L1 from the wellhead starting point to the position where the temperature along the way drops to the wall sticking temperature is calculated according to formula (3):

[0028]

[0029] In formula (3), L is the length of the oil gathering pipeline from the wellhead to the inlet, in meters; ψ is the axial heat dissipation parameter of the oil gathering pipeline, in meters -1 ; T GP is the freezing point of the oilfield produced fluid, in °C; φ is the comprehensive water content of the oilfield produced fluid, in %; τ is the shear stress at the inner wall of the oil gathering pipeline, in Pa; T0 is the temperature of the medium around the oil gathering pipeline, in °C;

[0030] k, m, and n are fitting parameters, determined experimentally;

[0031] The axial heat dissipation parameter ψ of the oil gathering pipeline in formula (3) is calculated according to formula (4):

[0032]

[0033] In formula (4), K is the heat transfer coefficient of the oil gathering pipeline, and its unit is W / (m 2 ·℃); D is the outer diameter of the oil gathering pipeline, in m; G is the mass flow rate of the oilfield produced fluid, in kg / s; c is the specific heat capacity of the oilfield produced fluid at the average oil gathering temperature, in J / (kg·℃);

[0034] The shear stress τ at the inner wall of the oil gathering pipeline in formula (3) is calculated according to formula (5):

[0035]

[0036] In formula (5), μ is the dynamic viscosity of the oilfield produced fluid, in Pa·s; R is the inner radius of the oil gathering pipeline, in m; v is the flow rate of the oilfield produced fluid in the oil gathering pipeline, in m / s;

[0037] In formula (1), the wall thickness δ of the wall-adherent oil section is calculated according to formula (6):

[0038]

[0039] In formula (6), t is the gathering and transportation time, the unit is d; Δ is the wall adhesion velocity, the unit is mm / d;

[0040] In formula (6), the wall sticking speed Δ is calculated according to formula (7):

[0041]

[0042] In formula (7), τ0 is the initial shear stress at the wall of the oil gathering pipeline, in Pa; φ is the comprehensive water content of the produced fluid in the oil field, in %; τ is the shear stress at the inner wall of the oil gathering pipeline, in Pa; T GP T is the freezing point of the oilfield produced fluid, in °C; w is the wall temperature of the oil gathering pipeline, in °C; d, e, f, g, h, i, j are fitting parameters, determined by experiments;

[0043] In formula (1), the hydraulic friction coefficient λ is calculated according to formula (8), formula (9), formula (10) and formula (11):

[0044] Laminar flow area:

[0045] Hydraulic smooth area:

[0046] Mixed friction zone:

[0047] Rough Area:

[0048] In formula (8), formula (9), formula (10) and formula (11), Re is the Reynolds number, ε is the relative equivalent roughness of the pipe wall, dimensionless; e represents the absolute equivalent roughness, unit is m; the applicable condition of formula (8) is Re<2000, and the applicable condition of formula (9) is The applicable conditions of formula (10) are: The applicable conditions of formula (11) are:

[0049] In formula (8), formula (9), formula (10) and formula (11), the Reynolds number Re is calculated according to formula (12), and the relative equivalent roughness ε of the pipe wall is calculated according to formula (13):

[0050]

[0051]

[0052] In formula (12), ω represents the kinematic viscosity of the produced fluid, m 2 / s; v is the flow rate of oilfield produced fluid in the oil gathering pipeline; R is the inner radius of the oil gathering pipeline, in meters.

[0053] In formula (13), e is the absolute equivalent roughness, in m; R is the inner radius of the oil gathering pipeline, in m.

[0054] In some embodiments provided by the present disclosure, the fitting method of the fitting parameters k, m, and n in the formula (3) is as follows: for multiphase produced fluids from oil fields with different comprehensive water contents, the condensation oil wall adhesion loop test is carried out to test the wall adhesion temperature T s , use the freezing point instrument to test the freezing point T GP , and determine the values ​​of k, m, and n by fitting.

[0055] In some embodiments provided in the present disclosure, k ranges from 5.31°C·Pa -n to 17.94℃·Pa -n ; The value range of m is 1.71 to 5.43; The value range of n is 0.19 to 0.67.

[0056] In some embodiments provided in the present disclosure, the k value increases with the increase of the oil phase wax content of the multiphase produced fluid of the oilfield, and the m and n values ​​decrease with the increase of the oil phase wax content of the multiphase produced fluid of the oilfield.

[0057] In some embodiments provided in the present disclosure, the fitting method of the fitting parameters d, e, f, g, h, i, and j in formula (5) is as follows: for multiphase produced fluids from oil fields with different comprehensive water contents, a condensation oil sticking to the wall loop experiment is conducted to test the sticking to the wall rate Δ, and the values ​​of d, e, f, g, h, i, and j are determined by fitting.

[0058] In some embodiments provided in the present disclosure, the value of d ranges from 0.001 m·s -1 ·Pa -e ℃ -j To 0.03m·s -1 ·Pa -e ℃ -j; e ranges from -1.91 to -0.53; f ranges from 0.37 to 0.99; g ranges from 4.27 to 8.63; h ranges from -0.99 to -0.03; i ranges from -2.14 to -0.99; j ranges from 1.75 to 4.99.

[0059] The values ​​of d, e, h, and i increase with the increase of wax content in the oil phase of multiphase produced fluid from the oil field;

[0060] The f, g, and j values ​​decrease as the wax content in the oil phase of the multiphase produced fluid from the oil field increases.

[0061] In some embodiments provided in the present disclosure, the method for obtaining the critical wall-sticking temperature comprises the following steps:

[0062] Obtain the following parameters: the freezing point T of the oilfield produced fluid GP , the comprehensive water content of the oilfield produced fluid φ, the shear stress τ at the inner wall of the oil gathering pipeline,

[0063] The critical wall sticking temperature T s Calculate according to formula (14):

[0064] T s =T GP -kφ m τ m …………………………(14)

[0065] In formula (14), T GP is the freezing point of the oilfield produced fluid, in °C; φ is the comprehensive water content of the oilfield produced fluid; τ is the shear stress at the inner wall of the oil gathering pipeline, in Pa;

[0066] k, m, n are fitting parameters, which are the same as the fitting parameters k, m, n in formula (3).

[0067] In some embodiments provided in the present disclosure, the emulsified water content of the oilfield produced fluid is 0 to 47%.

[0068] In some embodiments provided by the present disclosure, the water content of the oilfield produced fluid is 70% to 99%.

[0069] In some embodiments provided by the present disclosure, the fitting method of the fitting parameters k, m, n in the formula (3) and the formula (14) and the fitting parameters d, e, f, g, h, i, j in the formula (7) includes:

[0070] For multiphase produced fluids from oilfields with different comprehensive water contents, the condensation oil wall sticking loop test was carried out to test the wall sticking temperature T sand wall adhesion velocity Δ, the material of the ring channel is the same as the material conditions of the pipeline in the gathering and transportation method, and the values ​​of k, m, n and d, e, f, g, h, i, j are determined by fitting:

[0071] Set up different comprehensive moisture content (φ1, φ2, φ3...φ n ) of oil-water mixture, and the freezing point (T GP1 ,T GP2 ,T GP3 ...T GPn ), use a density meter to test the density of the mixed liquid (ρ1, ρ2, ρ3...ρ n );

[0072] The prepared crude oil emulsion is used for loop test to circulate the oil-water mixture in the pipeline and slowly cool the system. The length of the test section is κ. When the test data shows that the pressure difference in the test section continues to increase, the system temperature value at this time is the test wall adhesion temperature (T s1 ,T s2 ,T s3 ...T sn ), according to formula (5), the shear stress at the pipe wall is calculated as (τ1, τ2, τ3...τ n ), the initial shear stress at the tube wall is τ0, and the temperature at the test tube wall is T w ;

[0073] After running for a period of time, record the pipeline pressure difference (ΔP1, ΔP2, ΔP3...ΔP n ), and after a period of Δt, the pressure differences are recorded as (ΔP′1, ΔP′2, ΔP′3...ΔP′ n );

[0074] According to formula (15), the wall adhesion rate of mixed liquids with different water contents is calculated as follows:

[0075]

[0076] In formula (15), v is the flow rate of the oilfield produced fluid in the oil gathering pipeline (in formula (15), it is the flow rate of the mixed fluid in the loop test), in m / s; κ is the length of the test section, in m; the density of the mixed fluid tested by the densitometer (ρ1, ρ2, ρ3...ρ n ), unit is kg / m 3 ; λ is the hydraulic friction coefficient, dimensionless; Δt is the experimental running time, unit is s; (ΔP1, ΔP2, ΔP3...ΔP n ) is in Pa, (ΔP′1, ΔP′2, ΔP′3...ΔP′ n) is in Pa;

[0077] The calculated wall adhesion rates of oil-water mixtures with different water contents are (Δ1, Δ2, Δ3...Δ n );

[0078] According to the experimental data set (T s1 ,T s2 ,T s3 ...T sn )、(T GP1 ,T GP2 ,T GP3 ...T GPn )、(φ1,φ2,φ3...φ n )、(τ1,τ2,τ3...τ n ), and the wall temperature calculation formula (14) is fitted by the least square method: T s =T GP -kφ m τ n , determine the values ​​of fitting parameters k, m, and n;

[0079] According to the experimental data set (Δ1, Δ2, Δ3...Δ n )、(φ1,φ2,φ3...φ n )、(τ1,τ2,τ3...τ n )、(T GP1 ,T GP2 ,T GP3 ...T GPn ), and τ0, T w , use the least squares method to fit the wall adhesion rate calculation formula (7) and determine the values ​​of the fitting parameters d, e, f, g, h, i, and j.

[0080] In some embodiments provided by the present disclosure, the fitting parameters a and b in formula (2) are fitted using the following experiment:

[0081] The yield stress of waxy crude oil increases exponentially with the decrease of measurement temperature, which conforms to formula (16):

[0082] τ y =exp(a-bT)……………………(16)

[0083] In the formula, τ y is the yield stress of the wall-adherent hydrated oil, Pa; T is the yield stress test temperature, ℃; a and b are experimental fitting parameters.

[0084] The yield stress of oilfield produced fluid is tested by adjusting the temperature, and the fitting parameters a and b in formula (2) are obtained by fitting.

[0085] In some embodiments provided in the present disclosure, a ranges from 5.72 to 43.69; b ranges from 0.01 to 0.97.

[0086] In some embodiments provided in the present disclosure, the a value increases as the oil phase wax content of the oilfield multiphase produced fluid increases, and the b value decreases as the oil phase wax content of the oilfield multiphase produced fluid increases.

[0087] In another aspect, the present disclosure provides a system for gathering and transporting oilfield produced fluid, including the above-mentioned method for gathering and transporting oilfield produced fluid with extremely high water content, the system comprising:

[0088] The first acquisition module is used to obtain parameters: the maximum allowable back pressure P0 of the oilfield produced fluid at the starting point of the oil gathering pipeline, the inner radius R of the oil gathering pipeline, the density ρ of the oilfield produced fluid, the dynamic viscosity μ of the oilfield produced fluid, the flow rate v of the oilfield produced fluid in the oil gathering pipeline, the inlet pressure P1 of the oilfield produced fluid at the end of the oil gathering pipeline, the comprehensive water content φ of the oilfield produced fluid, and the emulsified water content of the oilfield produced fluid The length of the oil gathering pipeline from the wellhead to the inlet is L, and the freezing point T of the oil field produced fluid is GP , the wall temperature of the oil gathering pipeline is T w , the temperature of the medium around the oil gathering pipeline T0, the absolute equivalent roughness e, the heat transfer coefficient K of the oil gathering pipeline, the outer diameter D of the oil gathering pipeline, the mass flow rate G of the oil field produced liquid, the specific heat capacity c of the oil field produced liquid at the average oil gathering temperature, the gathering and transportation time t, the initial shear stress τ0 at the wall of the oil gathering pipeline, and the kinematic viscosity ω of the produced liquid;

[0089] The second acquisition module is used to calculate the critical gathering and transportation temperature of the oilfield produced fluid using the formula (1) to the formula (13) and the formula (15) to the formula (16); and calculate the critical wall sticking temperature of the oilfield produced fluid using the formula (14) and the formula (15);

[0090] A third acquisition module is used to determine the target gathering and transportation temperature of the oilfield produced fluid according to the critical gathering and transportation temperature of the oilfield produced fluid; the target gathering and transportation temperature of the oilfield produced fluid is greater than the critical gathering and transportation temperature of the oilfield produced fluid and less than the critical wall adhesion temperature of the oilfield produced fluid;

[0091] The gathering and transportation module is used to gather and transport the oilfield produced fluid at the target gathering and transportation temperature.

[0092] In yet another aspect, the present disclosure provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the method as claimed in claim 1 when running the computer program.

[0093] In yet another aspect, the present disclosure provides a storage medium for storing a computer-readable program, wherein when the computer-readable program is executed, the above method is executed.

[0094] Compared with the prior art, the above technical solution provided by the embodiments of the present disclosure has at least the following advantages:

[0095] The present invention calculates the critical gathering temperature of the produced fluid from the oil field with extra-high water content to be collected and transported through the calculation function relationship of the critical gathering temperature; determines the target gathering temperature of the produced fluid from the oil field to be collected and transported according to the critical gathering temperature of the produced fluid from the oil field to be collected and transported; wherein the target gathering temperature of the produced fluid from the oil field to be collected and transported is greater than the critical gathering temperature of the produced fluid from the oil field to be collected and transported, and less than the critical wall sticking temperature of the produced fluid from the oil field to be collected and transported; and collects and transports the produced fluid from the oil field to be collected and transported at the target gathering temperature. The critical gathering temperature of the crude oil with extra-high water content that can be safely collected and transported below the critical wall sticking temperature can be conveniently and accurately determined. Thus, the energy consumption of the oil field can be further reduced while ensuring safe collection and transport.

[0096] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or be understood by implementing the present disclosure. Other advantages of the present disclosure can be invented and obtained by the schemes described in the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0097] The accompanying drawings are used to provide an understanding of the technical solution of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solution of the present disclosure and do not constitute a limitation on the technical solution of the present disclosure.

[0098] Figure 1 It is an exemplary schematic diagram of the distribution characteristics of sticky wall condensed oil along the oil gathering pipeline according to some embodiments of the present disclosure.

[0099] Figure 2 It is an exemplary schematic diagram of the wall thickness and the arc length of the adhesion cross section of the wall-adhesive oil-condensing section according to some embodiments of the present disclosure.

[0100] Figure 3 It is an exemplary schematic diagram of a gathering and transportation system for oilfield produced fluid with extremely high water content according to some embodiments of the present disclosure.

[0101] Figure 4 It is a schematic diagram of an exemplary structure of an electronic device according to some embodiments of the present disclosure.

[0102] Figure 5 This is a schematic diagram showing the influence of the critical gathering temperature obtained based on the guidance of Example 1 on the change of the back pressure at the oil gathering wellhead when gathering and transportation are carried out at a gathering temperature of 22°C and a gathering temperature of 20°C below the critical wall sticking temperature. DETAILED DESCRIPTION

[0103] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present disclosure. For ordinary technicians in this field, the present disclosure can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0104] It should be understood that the "system", "device", "unit" and / or "module" used herein are a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

[0105] As shown in the present disclosure and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0106] Flowcharts are used in this disclosure to illustrate the operations performed by the system according to the embodiments of the present disclosure. It should be understood that the preceding or following operations are not necessarily performed precisely in order. Instead, the various steps may be processed in reverse order or simultaneously. At the same time, other operations may also be added to these processes, or one or more operations may be removed from these processes.

[0107] The present disclosure exemplarily provides a method for collecting and transporting oilfield produced fluid with extremely high water content, the method comprising:

[0108] The target gathering and transportation temperature of the oilfield produced fluid is set to be greater than the critical gathering and transportation temperature of the oilfield produced fluid and less than the critical wall adhesion temperature of the oilfield produced fluid;

[0109] The critical gathering and transportation temperature of the oilfield produced fluid is: the gathering and transportation temperature at which the adhesion force of the sticky wall condensed oil section formed by the accumulation of sticky wall water-containing condensed oil generated in the process of gathering and transportation of the oilfield produced fluid along the oil gathering pipeline to the pipe wall of the oil gathering pipeline is equal to the squeezing force of the pressure difference generated by the oilfield produced fluid on the sticky wall condensed oil section.

[0110] Exemplarily, the method for obtaining the critical gathering and transmission temperature T1 comprises the following steps:

[0111] Get the following parameters:

[0112] The maximum allowable back pressure P0 of the oilfield produced fluid at the starting point of the oil gathering pipeline, the inner radius R of the oil gathering pipeline, the density ρ of the oilfield produced fluid, the dynamic viscosity μ of the oilfield produced fluid, the flow rate v of the oilfield produced fluid in the oil gathering pipeline, the inlet pressure P1 of the oilfield produced fluid at the end of the oil gathering pipeline, the comprehensive water content φ of the oilfield produced fluid, and the emulsified water content of the oilfield produced fluid The length of the oil gathering pipeline from the wellhead to the inlet is L, and the freezing point T of the oil field produced fluid is GP , the wall temperature of the oil gathering pipeline is T w , the temperature of the medium around the oil gathering pipeline T0, the absolute equivalent roughness e, the heat transfer coefficient K of the oil gathering pipeline, the outer diameter D of the oil gathering pipeline, the mass flow rate G of the oil field produced fluid, the specific heat capacity c of the oil field produced fluid at the average oil gathering temperature, the gathering and transportation time t, the initial shear stress τ0 at the wall of the oil gathering pipeline, and the kinematic viscosity ω of the oil field produced fluid;

[0113] The above parameters can be categorized as:

[0114] (1) Physical properties of oilfield produced fluid: density ρ of oilfield produced fluid, dynamic viscosity μ of oilfield produced fluid, flow rate v of oilfield produced fluid in the oil gathering pipeline, comprehensive water content φ of oilfield produced fluid, emulsified water content of oilfield produced fluid The pour point T of oilfield produced fluid GP , the specific heat capacity c of the oilfield produced fluid at the average oil collection temperature, and the kinematic viscosity ω of the oilfield produced fluid.

[0115] (2) Specification parameters of the oil gathering pipeline: inner radius R of the oil gathering pipeline, outer diameter D of the oil gathering pipeline, absolute equivalent roughness e, length L of the oil gathering pipeline from the wellhead to the inlet, and heat transfer coefficient K of the oil gathering pipeline.

[0116] (3) Operation parameters: the maximum allowable back pressure P0 of the oilfield produced fluid at the starting point of the oil gathering pipeline, the inlet pressure P1 of the oilfield produced fluid at the end of the oil gathering pipeline, the mass flow rate G of the oilfield produced fluid, the gathering and transportation time t, the initial shear stress τ0 at the wall of the oil gathering pipeline, the wall temperature T of the oil gathering pipeline w , the temperature T0 of the medium around the oil gathering pipeline.

[0117] The critical gathering temperature T1 is calculated according to formula (1):

[0118]

[0119] In formula (1), P0 is the maximum allowable back pressure of the oilfield produced fluid at the starting point of the oil gathering pipeline, in Pa; λ is the hydraulic friction coefficient, dimensionless; L1 is the distance from the wellhead starting point where the temperature along the way drops to the wall temperature, in m; R is the inner radius of the oil gathering pipeline, in m; ρ is the density of the oilfield produced fluid, in kg / m 3; v is the flow rate of the oilfield produced fluid in the oil gathering pipeline, in m / s; P1 is the inlet pressure of the oilfield produced fluid at the end of the oil gathering pipeline, in Pa; δ is the wall thickness of the sticky wall condensation section, in m; φ is the comprehensive water content of the oilfield produced fluid, %; is the emulsified water content of the oilfield produced fluid, %;

[0120] In formula (1), the f -1 (F1) is the inverse function of F1=f(T1), and the original function F1=f(T1) is shown in formula (2):

[0121]

[0122] In formula (2), R is the inner radius of the oil gathering pipeline, in meters; φ is the comprehensive water content of the produced fluid in the oil field, in %; is the emulsified water content of the oilfield produced fluid, %; L1 is the distance from the wellhead starting point where the temperature drops to the wall-adhering temperature, in m; L2 is the distance from the end of the pipeline where the temperature drops to the wall-adhering temperature, in m (L2 = L-L1); L is the length of the oil gathering pipeline from the wellhead to the inlet, in m; T0 is the temperature of the medium surrounding the oil gathering pipeline, in ℃; ψ is the axial heat dissipation parameter of the oil gathering pipeline, in m -1 ; l is the distance between the micro-element segment of the oil-gathering pipeline dl and the starting point of the pipeline, in m; the oil temperature on the micro-element segment of the oil-gathering pipeline dl is T, in °C; a and b are fitting parameters, determined by experiments;

[0123] Formula (2) F1 is a function of T1, and formula (1) is the inverse function of formula (2). When using formula (1), F1 in formula (1) is calculated using formula (1.1);

[0124]

[0125] In formula (1.1), P0 is the maximum allowable back pressure of the oilfield produced fluid at the starting point of the oil gathering pipeline, in Pa; λ is the hydraulic friction coefficient, dimensionless; L1 is the distance from the wellhead starting point where the temperature along the way drops to the wall temperature, in m; R is the inner radius of the oil gathering pipeline, in m; ρ is the density of the oilfield produced fluid, in kg / m 3 ; v is the flow rate of the oilfield produced fluid in the oil gathering pipeline, in m / s; P1 is the inlet pressure of the oilfield produced fluid at the end of the oil gathering pipeline, in Pa; δ is the wall thickness of the sticky wall condensation section, in m; φ is the comprehensive water content of the oilfield produced fluid, %; is the emulsified water content of the oilfield produced fluid, %.

[0126] In formula (1), the distance L1 from the wellhead starting point to the position where the temperature along the way drops to the wall sticking temperature is calculated according to formula (3):

[0127]

[0128] In formula (3), L is the length of the oil gathering pipeline from the wellhead to the inlet, in meters; ψ is the axial heat dissipation parameter of the oil gathering pipeline, in meters -1 ; T GP is the freezing point of the oilfield produced fluid, in °C; φ is the comprehensive water content of the oilfield produced fluid, in %; τ is the shear stress at the inner wall of the oil gathering pipeline, in Pa; T0 is the temperature of the medium around the oil gathering pipeline, in °C;

[0129] k, m, and n are fitting parameters, determined experimentally;

[0130] The axial heat dissipation parameter ψ of the oil gathering pipeline in formula (3) is calculated according to formula (4):

[0131]

[0132] In formula (4), K is the heat transfer coefficient of the oil gathering pipeline, and its unit is W / (m 2 ·℃); D is the outer diameter of the oil gathering pipeline, in m; G is the mass flow rate of the oilfield produced fluid, in kg / s; c is the specific heat capacity of the oilfield produced fluid at the average oil gathering temperature, in J / (kg·℃);

[0133] The shear stress τ at the inner wall of the oil gathering pipeline in formula (3) is calculated according to formula (5):

[0134]

[0135] In formula (5), μ is the dynamic viscosity of the oilfield produced fluid, in Pa·s; R is the inner radius of the oil gathering pipeline, in m; v is the flow rate of the oilfield produced fluid in the oil gathering pipeline, in m / s;

[0136] In formula (1), the wall thickness δ of the wall-adherent oil section is calculated according to formula (6):

[0137]

[0138] In formula (6), t is the gathering and transportation time, in d; Δ is the wall adhesion velocity, in mm / d;

[0139] In formula (6), the wall sticking speed Δ is calculated according to formula (7):

[0140]

[0141] In formula (7), τ0 is the initial shear stress at the wall of the oil gathering pipeline, in Pa; φ is the comprehensive water content of the produced fluid in the oil field, in %; τ is the shear stress at the inner wall of the oil gathering pipeline, in Pa; T GP T is the freezing point of the oilfield produced fluid, in °C; w is the wall temperature of the oil gathering pipeline, in °C; d, e, f, g, h, i, j are fitting parameters, determined by experiments;

[0142] In formula (1), the hydraulic friction coefficient λ is calculated according to formula (8), formula (9), formula (10) and formula (11):

[0143] Laminar flow area:

[0144] Hydraulic smooth area:

[0145] Mixed friction zone:

[0146] Rough Area:

[0147] In formula (8), formula (9), formula (10) and formula (11), Re is the Reynolds number, ε is the relative equivalent roughness of the pipe wall, dimensionless; e represents the absolute equivalent roughness, unit is m; the applicable condition of formula (8) is Re<2000, and the applicable condition of formula (9) is The applicable conditions of formula (10) are: The applicable conditions of formula (11) are:

[0148] In formula (8), formula (9), formula (10) and formula (11), the Reynolds number Re is calculated according to formula (12), and the relative equivalent roughness ε of the pipe wall is calculated according to formula (13):

[0149]

[0150]

[0151] In formula (12), ω represents the kinematic viscosity of the produced fluid, m 2 / s; v is the flow rate of oilfield produced fluid in the oil gathering pipeline, in m / s; R is the inner radius of the oil gathering pipeline, in m.

[0152] In formula (13), e is the absolute equivalent roughness, in m; R is the inner radius of the oil gathering pipeline, in m.

[0153] Exemplarily, the fitting parameters a and b in formula (2) are fitted using the following experiment:

[0154] The yield stress of waxy crude oil increases exponentially with the decrease of measurement temperature, which conforms to formula (16):

[0155] τ y =exp(a-bT)……………………(16)

[0156] In the formula, τ y is the yield stress of the wall-adherent hydrated oil, Pa; T is the yield stress test temperature, ℃; a and b are experimental fitting parameters.

[0157] The yield stress of oilfield produced fluid is tested by adjusting the temperature, and the fitting parameters a and b in formula (2) are obtained by fitting.

[0158] Exemplarily, the value range of a is 5.72 to 43.69; the value range of b is 0.01 to 0.97.

[0159] Exemplarily, the a value increases as the wax content of the oil phase of the multiphase produced fluid of the oilfield increases, and the b value decreases as the wax content of the oil phase of the multiphase produced fluid of the oilfield increases.

[0160] For example, the fitting method of the fitting parameters k, m, and n in the formula (3) is as follows: for multiphase produced fluids from oil fields with different comprehensive water contents, the condensation oil wall adhesion loop test is carried out to test the wall adhesion temperature T s , use the freezing point instrument to test the freezing point T GP , and determine the values ​​of k, m, and n by fitting.

[0161] For example, the value range of k is 5.31°C·Pa -n to 17.94℃·Pa -n ; The value range of m is 1.71 to 5.43; The value range of n is 0.19 to 0.67.

[0162] For example, the k value increases with the increase of the oil phase wax content of the multiphase produced fluid of the oilfield, and the m and n values ​​decrease with the increase of the oil phase wax content of the multiphase produced fluid of the oilfield.

[0163] Exemplarily, the fitting method of the fitting parameters d, e, f, g, h, i, and j in formula (5) is as follows: for multiphase produced fluids from oil fields with different comprehensive water contents, a condensate sticking loop experiment is conducted to test the sticking rate Δ, and the values ​​of d, e, f, g, h, i, and j are determined by fitting.

[0164] For example, the value range of d is 0.001 m·s -1 ·Pa -e ℃ -j To 0.03m·s -1 ·Pa -e ℃ -j; e ranges from -1.91 to -0.53; f ranges from 0.37 to 0.99; g ranges from 4.27 to 8.63; h ranges from -0.99 to -0.03; i ranges from -2.14 to -0.99; j ranges from 1.75 to 4.99.

[0165] The values ​​of d, e, h, and i increase with the increase of wax content in the oil phase of multiphase produced fluid from the oil field;

[0166] The f, g, and j values ​​decrease as the wax content in the oil phase of the multiphase produced fluid from the oil field increases.

[0167] Exemplarily, the method for obtaining the critical wall-adhesion temperature comprises the following steps:

[0168] Obtain the following parameters: the freezing point T of the oilfield produced fluid GP , the comprehensive water content of the oilfield produced fluid φ, the shear stress τ at the inner wall of the oil gathering pipeline,

[0169] The critical wall sticking temperature T s Calculate according to formula (14):

[0170] T s =T GP -kφ m τ n …………………………(14)

[0171] In formula (14), T GP is the freezing point of the oilfield produced fluid, in °C; φ is the comprehensive water content of the oilfield produced fluid; τ is the shear stress at the inner wall of the oil gathering pipeline, in Pa;

[0172] k, m, n are fitting parameters, which are the same as the fitting parameters k, m, n in formula (3).

[0173] For example, the emulsified water content of the oilfield produced fluid is 0 to 47%.

[0174] Exemplarily, the water content of the oilfield produced fluid is 70% to 99%.

[0175] As an example only, Example 1: The material of a certain oil well gathering pipeline is carbon steel, the length from the wellhead to the inlet is L = 1300m, the inner radius of the gathering pipeline is R = 26mm, the maximum allowable wellhead back pressure of the oil field produced fluid at the starting point of the pipeline is P0 = 3.2MPa, the inlet pressure of the oil field produced fluid at the end of the gathering pipeline is P1 = 0.4MPa, the comprehensive water content of the oil field produced fluid is φ = 85.1%, and the emulsified water content of the oil field produced fluid is The density of oilfield produced fluid is ρ = 869 kg / m 3, the dynamic viscosity of the oilfield produced fluid μ = 0.19 Pa·s, the freezing point of the oilfield produced fluid T GP =32°C, the flow rate of oilfield produced fluid in the oil gathering pipeline is v=1.7m / s, and the temperature of the inner wall of the oil gathering pipeline is T w =20℃, the temperature of the medium around the oil collecting pipeline is T0=7℃, and the absolute equivalent roughness is e=0.14mm. The heat transfer coefficient of the oil collecting pipeline is K=1.4W / (m 2 ·℃), the outer diameter of the oil gathering pipeline D = 60mm, the mass flow rate of the oilfield produced fluid G = 3.2kg / s, the specific heat capacity of the oilfield produced fluid at the average oil gathering temperature c = 2900J / (kg·℃), the initial shear stress at the wall of the oil gathering pipeline τ0 = 48.3Pa, the gathering and transportation time t = 2d, and the kinematic viscosity of the produced fluid ω = 2.19×10 -4 m 2 / s.

[0176] Exemplarily, the fitting method of the fitting parameters k, m, n in the formula (3) and the formula (14) and the fitting parameters d, e, f, g, h, i, j in the formula (7) includes:

[0177] For multiphase produced fluids from oilfields with different comprehensive water contents, the condensation oil wall sticking loop test was carried out to test the wall sticking temperature T s and wall adhesion velocity Δ, the material of the ring channel is the same as the material conditions of the pipeline in the gathering and transportation method, and the values ​​of k, m, n and d, e, f, g, h, i, j are determined by fitting:

[0178] Set up different comprehensive moisture content (φ1, φ2, φ3...φ n ) of oil-water mixture, and the freezing point (T GP1 ,T GP2 ,T GP3 ...T GPn ), use a density meter to test the density of the mixed liquid (ρ1, ρ2, ρ3...ρ n );

[0179] The prepared crude oil emulsion was subjected to a loop test. The loop was made of carbon steel. The oil-water mixture was circulated in the pipeline to slowly cool the system. The length of the test section was κ. When the test data showed that the pressure difference in the test section continued to increase, the system temperature value at this time was the wall adhesion temperature (T) of the mixed liquid with different water contents. s1 ,T s2 ,T s3 ...T sn ), according to formula (5), the shear stress at the pipe wall is calculated as (τ1, τ2, τ3...τ n ), the initial shear stress at the tube wall is τ0, and the temperature at the test tube wall is Tw ;

[0180] After running for a period of time, record the pipeline pressure difference (ΔP1, ΔP2, ΔP3...ΔP n ), and after a period of Δt, the pressure differences are recorded as (ΔP′1, ΔP′2, ΔP′3...ΔP′ n );

[0181] According to formula (15), the wall adhesion rate of mixed liquids with different water contents is calculated as follows:

[0182]

[0183] In formula (15), v is the flow rate of the oilfield produced fluid in the oil gathering pipeline (in formula (15), it is the flow rate of the mixed fluid in the loop test), in m / s; κ is the length of the test section, in m; the density of the mixed fluid tested by the densitometer (ρ1, ρ2, ρ3...ρ n ), unit is kg / m 3 ; Δt is the experimental running time, in seconds; (ΔP1, ΔP2, ΔP3...ΔP n ) is in Pa, (ΔP′1, ΔP′2, ΔP′3...ΔP′ n ) is in Pa;

[0184] The calculated wall adhesion rates of oil-water mixtures with different water contents are (Δ1, Δ2, Δ3...Δ n );

[0185] According to the experimental data set (T s1 ,T s2 ,T s3 ...T sn )、(T GP1 ,T GP2 ,T GP3 ...T GPn )、(φ1,φ2,φ3...φ n )、(τ1,τ2,τ3...τ n ), and the wall temperature calculation formula (14) is fitted by the least square method: T s =T GP -kφ m τ n , determine the values ​​of fitting parameters k, m, and n;

[0186] According to the experimental data set (Δ1, Δ2, Δ3...Δ n )、(φ1,φ2,φ3...φ n )、(τ1,τ2,τ3...τ n )、(TGP1 ,T GP2 ,T GP3 ...T GPn ), and τ0, T w , use the least squares method to fit the wall adhesion rate calculation formula (7) and determine the values ​​of the fitting parameters d, e, f, g, h, i, and j.

[0187] The wall sticking temperature was tested by carrying out the condensate oil sticking to the wall loop experiment, and the fitting parameters k, m, and n were determined by fitting as shown in Table 1, all of which were within the aforementioned range.

[0188] Table 1

[0189] Fitting parameters <![CDATA[k(℃·Pa -n )]]> m n Numeric 12.69 2.65 0.21

[0190] The wall sticking rate was tested by carrying out the condensate oil sticking to the wall loop experiment, and the fitting parameters d, e, f, g, h, i, and j were determined by fitting as shown in Table 2, all of which were within the aforementioned range.

[0191] Table 2

[0192] Fitting parameters <![CDATA[d(m·s -1 ·Well -e ·℃ -j )]]> e f g h i j Numeric 0.002 -1.64 0.43 6.19 -0.93 -1.52 3.72

[0193] The fitting parameters a and b in formula (2) are fitted using the following experiment:

[0194] The yield stress of waxy crude oil increases exponentially with the decrease of measurement temperature, which conforms to formula (16):

[0195] τ y =exp(a-bT)……………………(16)

[0196] In the formula, τ y is the yield stress of the wall-adherent hydrated oil, Pa; T is the yield stress test temperature, ℃; a and b are experimental fitting parameters.

[0197] By adjusting the temperature, the yield stress of the oilfield produced fluid is tested, and the fitting parameters a and b in formula (2) are obtained by fitting. By adjusting the temperature, the yield stress of the oilfield produced fluid is tested, and the fitting parameters a and b in formula (2) can be determined by fitting according to formula (16). The values ​​are shown in Table 3, and are all within the above range.

[0198] Table 3

[0199] Fitting parameters a b Numeric 8.19 0.12

[0200] Substitute the above parameters into formula (4) as needed to obtain the axial heat dissipation parameter of the oil collecting pipeline in formula (3): ψ = 2.8 × 10 -5 m -1; Substitute the above parameters into formula (5) as needed to obtain the shear stress τ=49.7Pa at the inner wall of the oil gathering pipeline in formula (3), and calculate that the distance from the wellhead starting point to the position where the temperature along the way drops to the wall sticking temperature is L1=377m;

[0201] Substitute the above parameters into formula (7) as needed, substitute the shear stress τ at the inner wall of the oil gathering pipeline calculated by formula (5) into formula (7), and obtain the wall sticking speed Δ=1.55mm / d;

[0202] Substitute the above parameters into formula (6) as needed, introduce the parameter wall sticking speed Δ into formula (6), and calculate the wall sticking thickness δ of the wall sticking oil section, the wall sticking thickness δ of the wall sticking oil section is 3.1 mm;

[0203] Substitute the above parameters into formula (12) and formula (13) as needed to calculate the Reynolds number Re = 403.7 and the relative equivalent roughness of the pipe wall ε = 0.0054; according to the Reynolds number Re and the relative equivalent roughness of the pipe wall ε and formulas (8) to (11), the hydraulic friction coefficient λ = 0.16 is calculated;

[0204] For example, Figure 2 As shown in the figure, in this embodiment, the arc length of the condensate adhesion section accounts for the proportion of the circumference of the inner section of the pipeline

[0205] Substitute the above parameters into formula (1), formula (2) and formula (1.1) as needed; reduce the temperature along the way obtained by formula (3) to the distance L1=377m from the wellhead starting point at the sticky wall temperature position, and substitute it into formula (1), formula (2) and formula (1.1); substitute the sticky wall thickness δ of the sticky wall condensate section obtained by formula (6) and the hydraulic friction coefficient λ obtained by formulas (8) to (13) into formula (1) and formula (1.1) to calculate the critical gathering and transportation temperature T1=f -1 (F1) = 18°C;

[0206] Substitute the above parameters into formula (14) as needed, and substitute the shear stress τ at the inner wall of the oil gathering pipeline calculated by formula (5) into formula (14) to calculate the critical wall adhesion temperature T s =30℃;

[0207] It can be seen that the critical gathering temperature is nearly 12°C lower than the wall temperature.

[0208] In the field experiment, the well was cooled and oil was collected. First, the valve of the heating pipeline was adjusted to reduce the amount of hot water added to the pipeline, so that the return oil temperature was reduced to 4°C (i.e. 22°C) and 2°C (i.e. 20°C) above the critical gathering temperature. The oil collection experiment was carried out to monitor the changes in the wellhead back pressure. Figure 5 shown.

[0209] For oil collection conditions at 22°C, the effective flow area of ​​the pipeline is reduced due to the adhesion of condensed oil on the pipe wall, and the wellhead back pressure first increases and then stabilizes at around 1.3MPa; for oil collection conditions at 20°C, the wellhead back pressure first increases and then stabilizes at around 2.2MPa.

[0210] Under the above two conditions, the wellhead back pressure did not exceed the maximum allowable wellhead back pressure of 3.2MPa at the starting point of the pipeline, achieving safe oil collection and further reducing the gathering and transportation temperature from the critical wall sticking temperature by nearly 10°C, achieving energy saving and consumption reduction.

[0211] For example, the water content of the single well X4-2-F17 in the fourth oil mine of Daqing Oilfield is 96.1%, which is within the range of ultra-high water content. The wall sticking temperature under the operating water content is measured to be 32°C. Through the cooling test, it is found that the ultra-high water content crude oil of this single well can operate below the critical wall sticking temperature, and the return oil temperature can be reduced to below the critical wall sticking temperature (26°C) and operate normally.

[0212] When the temperature of the produced fluid from the oil field drops below the critical wall-sticking temperature, the yield stress of the wall-sticking hydrous condensate produced by the produced fluid from the oil field increases rapidly, and the shearing effect of the pipe flow is insufficient to peel the wall-sticking hydrous condensate from the pipe wall, resulting in the continuous adhesion of the wall-sticking hydrous condensate in the pipe, and the wall-sticking condensate section gradually thickens, causing the friction along the way to increase. The continuous oil coming from the bottom of the well forms a local blockage in the very narrow effective pipe diameter and continues to accumulate, and the average wellhead back pressure increases accordingly. During the operation of the pipeline, there are continuous block condensate oils and the wall-sticking condensate oil section. There is adhesion. With the increase of wellhead back pressure, when the top squeezing force generated by the pressure increase can just overcome the wall-sticking force generated by the yield stress of the wall-sticking condensate oil section, the block condensate oil on the wall-sticking condensate oil section is washed out of the pipeline, and the wellhead back pressure will decrease again, showing a periodic "restart" change as a whole. It can be seen that when the oilfield produced fluid is transmitted in the oil gathering pipeline, the balance between the pressure difference at both ends of the oil gathering pipeline caused by the condensed oil sticking to the wall phenomenon, which leads to the squeezing force on the condensed oil section sticking to the wall, and the adhesion force of the condensed oil section to the wall of the oil gathering pipeline caused by the yield stress of the condensed oil sticking to the wall is the key to ensuring the safe operation of the oilfield produced fluid in the gathering pipeline below the critical wall sticking temperature.

[0213] On the other hand, Figure 3 As shown, the embodiment of the present disclosure provides a system for collecting and transporting oilfield produced fluid, including the above-mentioned method for collecting and transporting oilfield produced fluid with extremely high water content, and the system includes:

[0214] The first acquisition module 810 is used to acquire parameters: the maximum allowable back pressure P0 of the oilfield produced fluid at the starting point of the oil gathering pipeline, the inner radius R of the oil gathering pipeline, the density ρ of the oilfield produced fluid, the dynamic viscosity μ of the oilfield produced fluid, the flow rate v of the oilfield produced fluid in the oil gathering pipeline, the inlet pressure P1 of the oilfield produced fluid at the end of the oil gathering pipeline, the comprehensive water content φ of the oilfield produced fluid, and the emulsified water content of the oilfield produced fluid. The length of the oil gathering pipeline from the wellhead to the inlet is L, and the freezing point T of the oil field produced fluid is GP , the wall temperature of the oil gathering pipeline is T w , the temperature of the medium around the oil gathering pipeline T0, the absolute equivalent roughness e, the heat transfer coefficient K of the oil gathering pipeline, the outer diameter D of the oil gathering pipeline, the mass flow rate G of the oil field produced liquid, the specific heat capacity c of the oil field produced liquid at the average oil gathering temperature, the gathering and transportation time t, the initial shear stress τ0 at the wall of the oil gathering pipeline, and the kinematic viscosity ω of the produced liquid;

[0215] The second acquisition module 820 is used to calculate the critical gathering and transportation temperature of the oilfield produced fluid using the formula (1) to the formula (13) and the formula (15) to the formula (16); and calculate the critical wall sticking temperature of the oilfield produced fluid using the formula (14) and the formula (15);

[0216] The third acquisition module 830 is used to determine the target gathering and transportation temperature of the oilfield produced fluid according to the critical gathering and transportation temperature of the oilfield produced fluid; the target gathering and transportation temperature of the oilfield produced fluid is greater than the critical gathering and transportation temperature of the oilfield produced fluid and less than the critical wall adhesion temperature of the oilfield produced fluid;

[0217] The gathering and transportation module 840 is used to gather and transport the oilfield produced fluid at the target gathering and transportation temperature. In the above-mentioned embodiment of the gathering and transportation system for oilfield produced fluid with extremely high water content, the specific processing of each module and the technical effects brought by it can be referred to the relevant description in the corresponding method embodiment, and will not be repeated here.

[0218] In yet another aspect, the present disclosure provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the method as claimed in claim 1 when running the computer program.

[0219] In yet another aspect, the present disclosure provides a storage medium for storing a computer-readable program, wherein when the computer-readable program is executed, the above method is executed.

[0220] Figure 4 It is a schematic diagram of an exemplary structure of an electronic device according to some embodiments of the present disclosure.

[0221] like Figure 4As shown, the electronic device includes: at least one processor 901, at least one communication interface 902, at least one memory 903 and at least one communication bus 904; optionally, the communication interface 902 may be an interface of a communication module, such as an interface of a GSM module; the processor 901 may be a processor CPU, or an application-specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present disclosure. The memory 903 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk storage. Among them, the memory 903 stores a program, and the processor 901 calls the program stored in the memory 903 to execute some or all of the above-mentioned method embodiments.

[0222] The present disclosure relates to a storage medium for storing a computer-readable program. When the computer-readable program is executed, part or all of the above method embodiments are executed.

[0223] Alternatively, the storage medium may be a non-transitory computer-readable storage medium, for example, the non-transitory computer-readable storage medium may be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like.

[0224] Based on the same inventive concept, an embodiment of the present disclosure further provides a computer program product, including a computer program, which implements part or all of the above method embodiments when executed by a processor.

[0225] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present disclosure. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and corrections to the present disclosure. Such modifications, improvements and corrections are suggested in the present disclosure, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of the present disclosure.

[0226] At the same time, the present disclosure uses specific words to describe the embodiments of the present disclosure. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present disclosure. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in the present disclosure does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present disclosure may be appropriately combined.

[0227] In addition, unless explicitly stated in the claims, the order of the processing elements and sequences described in the present disclosure, the use of alphanumeric characters, or the use of other names are not intended to limit the order of the processes and methods of the present disclosure. Although the above disclosure discusses some invention embodiments that are currently considered useful through various examples, it should be understood that such details are only for illustrative purposes, and the attached claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of the present disclosure. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on an existing server or mobile device.

[0228] Similarly, it should be noted that in order to simplify the description of the disclosure and thus help understand one or more embodiments of the invention, in the above description of the embodiments of the disclosure, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of the disclosure are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0229] In some embodiments, numbers are used to describe the number of components and attributes. It should be understood that such numbers used to describe the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of the range in some embodiments of the present disclosure are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0230] Each patent, patent application, patent application publication, and other materials, such as articles, books, instructions, publications, documents, etc., cited in this disclosure are hereby incorporated by reference in their entirety. Except for application history documents that are inconsistent with or conflicting with the content of this disclosure, documents that limit the broadest scope of the claims of this disclosure (currently or later attached to this disclosure) are also excluded. It should be noted that if the descriptions, definitions, and / or use of terms in the accompanying materials of this disclosure are inconsistent or conflicting with the content of this disclosure, the descriptions, definitions, and / or use of terms in this disclosure shall prevail.

[0231] Finally, it should be understood that the embodiments described in this disclosure are only used to illustrate the principles of the embodiments of the present disclosure. Other variations may also fall within the scope of the present disclosure. Therefore, as examples and not limitations, alternative configurations of the embodiments of the present disclosure may be considered consistent with the teachings of the present disclosure. Accordingly, the embodiments of the present disclosure are not limited to the embodiments explicitly introduced and described in the present disclosure.

Claims

1. A method for collecting and transporting oilfield produced fluid with extremely high water content, characterized in that: The method comprises: The target gathering and transportation temperature of the oilfield produced fluid is set to be greater than the critical gathering and transportation temperature of the oilfield produced fluid and less than the critical wall adhesion temperature of the oilfield produced fluid; The critical gathering and transportation temperature of the oilfield produced fluid is: the gathering and transportation temperature at which the adhesion force of the sticky wall condensed oil section formed by the accumulation of sticky wall water-containing condensed oil generated in the process of gathering and transportation of the oilfield produced fluid along the oil gathering pipeline to the pipe wall of the oil gathering pipeline is equal to the squeezing force of the pressure difference generated by the oilfield produced fluid on the sticky wall condensed oil section.

2. The method according to claim 1, characterized in that The method for obtaining the critical gathering and transmission temperature T1 comprises the following steps: Get the following parameters: The maximum allowable back pressure P0 of the oilfield produced fluid at the starting point of the oil gathering pipeline, the inner radius R of the oil gathering pipeline, the density ρ of the oilfield produced fluid, the dynamic viscosity μ of the oilfield produced fluid, the flow rate v of the oilfield produced fluid in the oil gathering pipeline, the inlet pressure P1 of the oilfield produced fluid at the end of the oil gathering pipeline, the comprehensive water content φ of the oilfield produced fluid, and the emulsified water content of the oilfield produced fluid The length of the oil gathering pipeline from the wellhead to the inlet is L, and the freezing point T of the oil field produced fluid is GP , the wall temperature of the oil gathering pipeline is T w , the temperature of the medium around the oil gathering pipeline T0, the absolute equivalent roughness e, the heat transfer coefficient K of the oil gathering pipeline, the outer diameter D of the oil gathering pipeline, the mass flow rate G of the oil field produced fluid, the specific heat capacity c of the oil field produced fluid at the average oil gathering temperature, the gathering and transportation time t, the initial shear stress τ0 at the wall of the oil gathering pipeline, and the kinematic viscosity ω of the oil field produced fluid; The critical gathering temperature T1 is calculated according to formula (1): In formula (1), P0 is the maximum allowable back pressure of the oilfield produced fluid at the starting point of the oil gathering pipeline, in Pa; λ is the hydraulic friction coefficient, dimensionless; L1 is the distance from the wellhead starting point where the temperature along the way drops to the wall temperature, in m; R is the inner radius of the oil gathering pipeline, in m; ρ is the density of the oilfield produced fluid, in kg / m 3 ; v is the flow rate of the oilfield produced fluid in the oil gathering pipeline, in m / s; P1 is the inlet pressure of the oilfield produced fluid at the end of the oil gathering pipeline, in Pa; δ is the wall thickness of the sticky wall condensation section, in m; φ is the comprehensive water content of the oilfield produced fluid, %; is the emulsified water content of the oilfield produced fluid, %; In formula (1), the f -1 (F1) is the inverse function of F1=f(T1), and the original function F1=f(T1) is shown in formula (2): In formula (2), R is the inner radius of the oil gathering pipeline, in meters; φ is the comprehensive water content of the produced fluid in the oil field, in %; is the emulsified water content of the oilfield produced fluid, %; L1 is the distance from the wellhead starting point where the temperature drops to the wall-adhering temperature, in m; L2 is the distance from the end of the pipeline where the temperature drops to the wall-adhering temperature, in m (L2 = L-L1); L is the length of the oil gathering pipeline from the wellhead to the inlet, in m; T0 is the temperature of the medium surrounding the oil gathering pipeline, in ℃; ψ is the axial heat dissipation parameter of the oil gathering pipeline, in m -1 ; l is the distance between the micro-element segment of the oil-gathering pipeline dl and the starting point of the pipeline, in m; the oil temperature on the micro-element segment of the oil-gathering pipeline dl is T, in °C; a and b are fitting parameters, determined by experiments; In formula (1), the distance L1 from the wellhead starting point to the position where the temperature along the way drops to the wall sticking temperature is calculated according to formula (3): In formula (3), L is the length of the oil gathering pipeline from the wellhead to the inlet, in meters; ψ is the axial heat dissipation parameter of the oil gathering pipeline, in meters -1 ; T GP is the freezing point of the oilfield produced fluid, in °C; φ is the comprehensive water content of the oilfield produced fluid, in %; τ is the shear stress at the inner wall of the oil gathering pipeline, in Pa; T0 is the temperature of the medium around the oil gathering pipeline, in °C; k, m, and n are fitting parameters, determined experimentally; The axial heat dissipation parameter ψ of the oil gathering pipeline in formula (3) is calculated according to formula (4): In formula (4), K is the heat transfer coefficient of the oil gathering pipeline, and its unit is W / (m 2 ·℃); D is the outer diameter of the oil gathering pipeline, in m; G is the mass flow rate of the oilfield produced fluid, in kg / s; c is the specific heat capacity of the oilfield produced fluid at the average oil gathering temperature, in J / (kg·℃); The shear stress τ at the inner wall of the oil gathering pipeline in formula (3) is calculated according to formula (5): In formula (5), μ is the dynamic viscosity of the oilfield produced fluid, in Pa·s; R is the inner radius of the oil gathering pipeline, in m; v is the flow rate of the oilfield produced fluid in the oil gathering pipeline, in m / s; In formula (1), the wall thickness δ of the wall-adherent oil section is calculated according to formula (6): In formula (6), t is the gathering and transportation time, the unit is d; Δ is the wall adhesion velocity, the unit is mm / d; In formula (6), the wall sticking speed Δ is calculated according to formula (7): In formula (7), τ0 is the initial shear stress at the wall of the oil gathering pipeline, in Pa; φ is the comprehensive water content of the produced fluid in the oil field, in %; τ is the shear stress at the inner wall of the oil gathering pipeline, in Pa; T GP T is the freezing point of the oilfield produced fluid, in °C; w is the wall temperature of the oil gathering pipeline, in °C; d, e, f, g, h, i, j are fitting parameters, determined by experiments; In formula (1), the hydraulic friction coefficient λ is calculated according to formula (8), formula (9), formula (10) and formula (11): Laminar flow area: Hydraulic smooth area: Mixed friction zone: Rough Area: In formula (8), formula (9), formula (10) and formula (11), Re is the Reynolds number, ε is the relative equivalent roughness of the pipe wall, dimensionless; e represents the absolute equivalent roughness, unit is m; the applicable condition of formula (8) is Re<2000, and the applicable condition of formula (9) is The applicable conditions of formula (10) are The applicable conditions of formula (11) are: In formula (8), formula (9), formula (10) and formula (11), the Reynolds number Re is calculated according to formula (12), and the relative equivalent roughness ε of the pipe wall is calculated according to formula (13): In formula (12), ω represents the kinematic viscosity of the produced fluid, m 2 / s; v is the flow rate of oilfield produced fluid in the oil gathering pipeline; R is the inner radius of the oil gathering pipeline, in meters; In formula (13), e is the absolute equivalent roughness, in m; R is the inner radius of the oil gathering pipeline, in m.

3. The method according to claim 2, characterized in that The fitting method of the fitting parameters k, m, and n in the formula (3) is as follows: for multiphase produced fluids from oil fields with different comprehensive water contents, the condensation oil wall adhesion loop test is carried out to test the wall adhesion temperature T s , use the freezing point instrument to test the freezing point T GP , fit to determine the values ​​of k, m, and n; Optionally, the value range of k is 5.31℃·Pa -n to 17.94℃·Pa -n ; m ranges from 1.71 to 5.43; n ranges from 0.19 to 0.67; Optionally, the k value increases with the increase of the oil phase wax content of the oilfield multiphase produced fluid, and the m and n values ​​decrease with the increase of the oil phase wax content of the oilfield multiphase produced fluid.

4. The method according to claim 2, characterized in that: The fitting method of the fitting parameters d, e, f, g, h, i, j in the formula (5) is as follows: for multiphase produced fluids from oil fields with different comprehensive water contents, a condensation oil wall sticking loop experiment is conducted to test the wall sticking rate Δ, and the values ​​of d, e, f, g, h, i, j are determined by fitting; Optionally, the value range of d is 0.001 m·s -1 ·Pa -e ℃ -j To 0.03m·s -1 ·Pa -e ℃ -j ; e ranges from -1.91 to -0.53; f ranges from 0.37 to 0.99; g ranges from 4.27 to 8.63; h ranges from -0.99 to -0.03; i ranges from -2.14 to -0.99; j ranges from 1.75 to 4.99; The values ​​of d, e, h, and i increase with the increase of wax content in the oil phase of multiphase produced fluid from the oil field; The f, g, and j values ​​decrease as the wax content in the oil phase of the multiphase produced fluid from the oil field increases.

5. The method according to any one of claims 1 to 4, characterized in that The method for obtaining the critical wall-sticking temperature comprises the following steps: Obtain the following parameters: the freezing point T of the oilfield produced fluid GP , the comprehensive water content of the oilfield produced fluid φ, the shear stress τ at the inner wall of the oil gathering pipeline, The critical wall sticking temperature T s Calculate according to formula (14): T s =T GP -kφ m τ n …………………………(14) In formula (14), Y GP is the freezing point of the oilfield produced fluid, in °C; φ is the comprehensive water content of the oilfield produced fluid; τ is the shear stress at the inner wall of the oil gathering pipeline, in Pa; k, m, n are fitting parameters, which are the same as the fitting parameters k, m, n in formula (2).

6. The method according to any one of claims 5, characterized in that The fitting method of the fitting parameters k, m, n in the formula (3) and the formula (14) and the fitting parameters d, e, f, g, h, i, j in the formula (7) includes: For multiphase produced fluids from oilfields with different comprehensive water contents, the condensation oil wall sticking loop test was carried out to test the wall sticking temperature T s and the wall adhesion velocity Δ, and the values ​​of k, m, n and d, e, f, g, h, i, j are determined by fitting: Set up different comprehensive moisture content (φ1, φ2, φ3...φ n ) of oil-water mixture, and the freezing point (T GP1 ,T GP2 ,T GP3 ...T GPn ), use a density meter to test the density of the mixed liquid (ρ1, ρ2, ρ3...ρ n ); The prepared crude oil emulsion is used for loop test to circulate the oil-water mixture in the pipeline and slowly cool the system. The length of the test section is κ. When the test data shows that the pressure difference in the test section continues to increase, the system temperature value at this time is the test wall adhesion temperature (T s1 ,T s2 ,T s3 ...T sn ), according to formula (5), the shear stress at the pipe wall is calculated as (τ1, τ2, τ3...τ n ), the initial shear stress at the tube wall is τ0, and the temperature at the test tube wall is T w ; After running for a period of time, record the pipeline pressure difference (ΔP1, ΔP2, ΔP3...ΔP n ), and after a period of Δt, the pressure differences are recorded as (ΔP′1, ΔP′2, ΔP′3...ΔP′ n ); According to formula (15), the wall adhesion rate of mixed liquids with different water contents is calculated as follows: In formula (15), v is the flow rate of the oilfield produced fluid in the oil gathering pipeline (in formula (15), it is the flow rate of the mixed fluid in the loop test), in m / s; κ is the length of the test section, in m; the density of the mixed fluid tested by the densitometer (ρ1, ρ2, ρ3...ρ n ), unit is kg / m 3 ; λ is the hydraulic friction coefficient, dimensionless; Δt is the experimental running time, unit is s; (ΔP1, ΔP2, ΔP3...ΔP n ) is in Pa, (ΔP′1, ΔP′2, ΔP′3...ΔP′ n ) is in Pa; The calculated wall adhesion rates of oil-water mixtures with different water contents are (Δ1, Δ2, Δ3...Δ n ); According to the experimental data set (T s1 ,T s2 ,T s3 ...T sn )、(T GP1 ,T GP2 ,T GP3 ...T GPn )、(φ1,φ2,φ3...φ n )、(τ1,τ2,τ3...τ n ), and the wall temperature calculation formula (14) is fitted by the least square method: T s =T GP -kφ m τ n , determine the values ​​of fitting parameters k, m, and n; According to the experimental data set (Δ1, Δ2, Δ3...Δ n )、(φ1,φ2,φ3...φ n )、(τ1,τ2,τ3...τ n )、(T GP1 ,T GP2 ,T GP3 ...T GPn ), and τ0, T w , use the least square method to fit the wall adhesion rate calculation formula (7) to determine the values ​​of fitting parameters d, e, f, g, h, i, j; Optionally, the fitting parameters a and b in formula (2) are fitted according to formula (16): τ y =exp(a-bT)……………………………(16) In the formula, τ y is the yield stress of the hydrated oil on the wall, Pa; T is the yield stress test temperature, °C; a and b are experimental fitting parameters; The yield stress of oilfield produced fluid is tested by adjusting the temperature, and the fitting parameters a and b in formula (2) are obtained by fitting; Optionally, a ranges from 5.72 to 43.69; b ranges from 0.01 to 0.97; Optionally, the a value increases as the oil phase wax content of the oilfield multiphase produced fluid increases, and the b value decreases as the oil phase wax content of the oilfield multiphase produced fluid increases.

7. The method according to any one of claims 1 to 4, characterized in that The water content of the produced fluid from the ultra-high water content oil field is 70% to 99%.

8. A system for collecting and transporting oilfield produced fluid, comprising the method for collecting and transporting oilfield produced fluid with a very high water content according to any one of claims 1 to 7, characterized in that: The system comprises: The first acquisition module is used to obtain parameters: the maximum allowable back pressure P0 of the oilfield produced fluid at the starting point of the oil gathering pipeline, the inner radius R of the oil gathering pipeline, the density ρ of the oilfield produced fluid, the dynamic viscosity μ of the oilfield produced fluid, the flow rate v of the oilfield produced fluid in the oil gathering pipeline, the inlet pressure P1 of the oilfield produced fluid at the end of the oil gathering pipeline, the comprehensive water content φ of the oilfield produced fluid, and the emulsified water content of the oilfield produced fluid The length of the oil gathering pipeline from the wellhead to the inlet is L, and the freezing point T of the oil field produced fluid is GP , the wall temperature of the oil gathering pipeline is T w , the temperature of the medium around the oil gathering pipeline T0, the absolute equivalent roughness e, the heat transfer coefficient K of the oil gathering pipeline, the outer diameter D of the oil gathering pipeline, the mass flow rate G of the oil field produced liquid, the specific heat capacity c of the oil field produced liquid at the average oil gathering temperature, the gathering and transportation time t, the initial shear stress τ0 at the wall of the oil gathering pipeline, and the kinematic viscosity ω of the produced liquid; The second acquisition module is used to calculate the critical gathering and transportation temperature of the oilfield produced fluid using the formula (1) to the formula (13) and the formula (15) to the formula (16); and calculate the critical wall sticking temperature of the oilfield produced fluid using the formula (14) and the formula (15); A third acquisition module is used to determine the target gathering and transportation temperature of the oilfield produced fluid according to the critical gathering and transportation temperature of the oilfield produced fluid; the target gathering and transportation temperature of the oilfield produced fluid is greater than the critical gathering and transportation temperature of the oilfield produced fluid and less than the critical wall adhesion temperature of the oilfield produced fluid; The gathering and transportation module is used to gather and transport the oilfield produced fluid at the target gathering and transportation temperature.

9. An electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the method according to any one of claims 1 to 7 when running the computer program.

10. A storage medium for storing a computer-readable program, wherein when the computer-readable program is executed, the method according to any one of claims 1 to 7 is executed.

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