Viscosity reduction system, method and device for oilfield produced liquid and electronic equipment

Abstract

The embodiment of the invention provides a viscosity reduction system, method and device for oil field produced liquid and electronic equipment. The viscosity reduction system for the oil field produced liquid comprises a first oil collecting pipe, a watering pipeline and a second oil collecting pipe. Wherein the watering pipeline is communicated with the first oil collecting pipe at a first connecting point, one end of the second oil collecting pipe is communicated with the first oil collecting pipe between an oil well and the first connecting point at a second connecting point, and the other end of the second oil collecting pipe is communicated with the first oil collecting pipe at a third connecting point. The third connecting point is located in the direction, away from the oil well, of the first connecting point. According to the viscosity reduction system provided by the invention, a secondary mixing method can be adopted, and the transportation cost of the oil field produced liquid can be reduced while the viscosity of the oil field produced liquid in the oil collection pipeline is reduced.

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 viscosity reduction system, method, device, and electronic equipment for oilfield produced fluid. Background Art

[0002] In the early stage of crude oil extraction, the water content of the oilfield produced fluid obtained from the oil well is relatively low (the water content of the oilfield produced fluid <20vol.%). As the crude oil extraction continues, the water content of the oilfield produced fluid in the oil well gradually increases. When the oilfield produced fluid is in the medium water content stage (20vol.%≤the water content of the oilfield produced fluid <60vol.%), the oilfield produced fluid is easy to become an oil-in-water emulsion, which will cause the viscosity of the oilfield produced fluid to rise sharply.

[0003] Usually, a large amount of water is added to the oil gathering pipeline at one time to make the oil field produced fluid change from oil-in-water emulsion (higher viscosity) to water-in-oil emulsion (lower viscosity), thereby reducing the transportation friction resistance. However, this method of mixing oil and water at one time consumes a large amount of water resources, resulting in higher transportation costs for oil field produced fluid.

[0004] Therefore, how to reduce the transportation cost of oilfield produced fluid while reducing the viscosity of oilfield produced fluid in the oil gathering pipeline 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] The present application exemplarily provides a viscosity reduction system for oilfield produced fluid, the system comprising: a first oil collecting pipe, a water mixing pipe and a second oil collecting pipe; wherein:

[0007] The water injection pipeline is connected to the first oil collecting pipe at a first connection point, one end of the second oil collecting pipe is connected to the first oil collecting pipe between the oil well and the first connection point at a second connection point, and the other end of the second oil collecting pipe is connected to the first oil collecting pipe at a third connection point, and the third connection point is located in the direction of the first connection point away from the oil well;

[0008] The second connection point is configured to split the oilfield produced fluid into the first oil collecting pipe and the second oil collecting pipe; the oilfield produced fluid in the first oil collecting pipe is recorded as the first produced fluid, and the oilfield produced fluid in the second oil collecting pipe is recorded as the second produced fluid;

[0009] The first connection point is configured to evenly mix the first produced liquid and the water in the water-injection pipeline; the liquid mixed at the first connection point is recorded as a first mixed liquid;

[0010] The third connection point is configured to mix the first mixed liquid and the second produced liquid evenly, and the liquid mixed at the third connection point is recorded as the second mixed liquid.

[0011] In one embodiment provided in the present application, the first connection point is configured to allow the first mixed liquid to flow along the first oil collecting pipe to the third connection point.

[0012] In one embodiment provided in the present application, the third connection point is configured so that the second mixed liquid flows out along the first oil collecting pipe in a direction away from the first connection point.

[0013] In one embodiment provided in the present application, the ratio of the length of the pipeline between the first connection point and the second connection point to the length of the pipeline between the first connection point and the third connection point is 1:(1 to 2);

[0014] In one embodiment provided in the present application, the ratio of the diameters of the first oil collecting pipe and the second oil collecting pipe is 1:(2 to 5).

[0015] In one embodiment provided in the present application, the material of the first oil collecting pipe is a hydrophilic material.

[0016] In another aspect, the present application provides a method for reducing the viscosity of oilfield produced fluid, using any of the above-mentioned oilfield produced fluid viscosity reduction systems, the method comprising:

[0017] Measuring or fitting the oil-water transition water content of the oilfield produced fluid;

[0018] Measuring or fitting the first viscosity value and the corresponding first water content of the oilfield produced fluid when the water content gradually increases under the water-in-oil condition, measuring the second viscosity value and the second water content of the oilfield produced fluid when the water content gradually decreases under the oil-in-water condition, and taking the water content when the first water content and the second water content are equal and the first viscosity value and the second viscosity value are equal as the critical water content;

[0019] According to the critical water content and the oil-water transition water content, determine the flow value of the first produced liquid in the first oil collecting pipe, the flow value of the water in the water mixing pipe, and the flow value of the second produced liquid in the second oil collecting pipe to meet the set conditions, wherein the set conditions include that the water content of the first mixed liquid is higher than the oil-water transition water content, and the water content of the second mixed liquid is higher than the critical water content and lower than the oil-water transition water content;

[0020] According to the flow value of the first produced liquid in the first oil collecting pipe, the flow value of water in the water mixing pipe and the flow value of the second produced liquid in the second oil collecting pipe, the viscosity reduction system of the oil field produced liquid is used to reduce the viscosity of the oil field produced liquid.

[0021] In one embodiment provided in the present application, the flow value of the first produced liquid in the first oil collecting pipe, the flow value of the water in the water blending pipeline, and the flow value of the second produced liquid in the second oil collecting pipe are determined according to the critical water cut and the oil-water transition water cut, including:

[0022] Based on the critical water cut, the oil-water transition water cut, the production value and water cut of the oilfield produced fluid in the oil well, the set conditions and the target viscosity value to be achieved, the flow value of the first produced fluid in the first oil collecting pipe, the flow value of the water in the water injection pipe and the flow value of the second produced fluid in the second oil collecting pipe are determined.

[0023] In one embodiment provided in the present application, the viscosity of the oilfield produced fluid in the viscosity reduction method is 10 mPa.s to 2000 mPa.s.

[0024] In one embodiment provided in the present application, the water content of the oilfield produced fluid does not exceed 75wt.%.

[0025] In one embodiment provided in the present application, the temperature of the first oil collecting pipe is set so as not to affect the water content of the first mixed liquid being higher than the oil-water transition water content, and the temperature of the second oil collecting pipe is set so as not to affect the water content of the second mixed liquid being higher than the critical water content and lower than the oil-water transition water content.

[0026] In one embodiment provided in the present application, the flow ratio of the first produced fluid and the second produced fluid is controlled to be 10:(11 to 100).

[0027] In one embodiment provided in the present application, the flow ratio of the first produced fluid and the water is controlled to be 10:(13 to 50).

[0028] In one embodiment provided in the present application, the viscosity reduction method does not use a flow modifier.

[0029] On the other hand, the present application provides an electronic device, which includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the above-mentioned method for reducing the viscosity of oilfield produced fluid when running the computer program.

[0030] On the other hand, the present application provides a storage device for storing a computer-readable program, wherein the computer-readable program executes the above-mentioned method for reducing the viscosity of oilfield produced fluid when executed.

[0031] The embodiment provided in the present application adopts a secondary mixing method through an oilfield produced fluid viscosity reduction system composed of a first oil collecting pipe, a water-doped pipe and a second oil collecting pipe: the oilfield produced fluid produced by the oil well is divided into a first produced fluid in the first oil collecting pipe and a second produced fluid in the second oil collecting pipe at a second connection point; the first produced fluid and the water in the water-doped pipe are mixed at the first connection point to obtain a first mixed fluid; the first mixed fluid and the second produced fluid are mixed at a third connection point to obtain a second mixed fluid with a lower viscosity value and a lower water content, thereby reducing the transportation cost of the oilfield produced fluid while reducing the viscosity of the oilfield produced fluid in the oil collecting pipe.

[0032] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be invented and obtained by the schemes described in the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0034] The present application will be further described in the form of exemplary embodiments, which will be described in detail by way of the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

[0035] Figure 1 It is a schematic diagram of an application scenario of the method for reducing the viscosity of oilfield produced fluid according to some embodiments of the present application.

[0036] Figure 2A is an exemplary schematic diagram of a viscosity reduction system for oilfield produced fluid according to some embodiments of the present application;

[0037] Figure 2B is an exemplary schematic diagram of a viscosity reduction system for oilfield produced fluids of a prior art;

[0038] Figure 3 is an exemplary flow chart of a method for reducing viscosity of oilfield produced fluid according to some embodiments of the present application;

[0039] Figure 4 is an exemplary schematic diagram of an oil-in-water upward curve, a water-in-oil upward curve, and a water-in-water downward curve according to some embodiments of the present application;

[0040] Figure 5 is an exemplary schematic diagram of a viscosity reduction device for oilfield produced fluid according to some embodiments of the present application;

[0041] Figure 6 It is a schematic diagram of an exemplary structure of an electronic device according to some embodiments of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present application more clear, the embodiments of the present application are described in detail below. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, 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 application. For ordinary technicians in this field, the present application 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.

[0044] 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.

[0045] As shown in this application 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 "comprises" and "includes" 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.

[0046] Flowcharts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, 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.

[0047] Figure 1 It is a schematic diagram of an application scenario of the method for reducing the viscosity of oilfield produced fluid according to some embodiments of the present application.

[0048] like Figure 1 As shown, the application scenario may include a server 110 , a terminal 120 and a network 130 .

[0049] In some embodiments, the server 110 and the terminal 120 may exchange data or information through the network 130. For example, the server 110 may obtain information and / or data in the terminal 120 through the network 130, or may send information and / or data to the terminal 120 through the network 130.

[0050] The terminal 120 is an electronic device used by the user to determine the flow value of the first produced liquid in the first oil collecting pipe, the flow value of the water in the water mixing pipe, and the flow value of the second produced liquid in the second oil collecting pipe. In some embodiments, the terminal 120 can obtain multiple sets of first data to be fitted, and fit the oil-in-water water content upward curve of the oilfield produced liquid according to the multiple sets of first data to be fitted. In some embodiments, the terminal 120 can obtain multiple sets of second data to be fitted, and fit the water-in-oil water content downward curve of the oilfield produced liquid according to the multiple sets of second data to be fitted. In some embodiments, the terminal 120 can use the water content corresponding to the intersection of the oil-in-water water content upward curve and the water-in-oil water content downward curve as the critical water content, and determine the flow value of the first produced liquid in the first oil collecting pipe, the flow value of the water in the water mixing pipe, and the flow value of the second produced liquid in the second oil collecting pipe according to the critical water content and the oil-water transition water content. In the case where the computing resources of the terminal 120 are limited, the terminal 120 can send multiple groups of first data to be fitted and multiple groups of second data to be fitted to the server 110, and the server 110 determines the flow value of the first produced liquid in the first oil collecting pipe, the flow value of water in the water mixing pipe, and the flow value of the oilfield produced liquid in the second oil collecting pipe according to the multiple groups of first data to be fitted and the multiple groups of second data to be fitted, and returns the flow value of the oilfield produced liquid in the first oil collecting pipe, the flow value of water in the water mixing pipe, and the flow value of the oilfield produced liquid in the second oil collecting pipe to the terminal 120, so that the terminal 120 displays the flow value of the first produced liquid in the first oil collecting pipe, the flow value of water in the water mixing pipe, and the flow value of the second produced liquid in the second oil collecting pipe to the user. The terminal 120 can be one of or any combination of devices with input and / or output functions such as a mobile device and a tablet computer.

[0051] The server 110 may be a single server or a server group. The server group may be centralized or distributed (for example, the server 110 may be a distributed system), may be dedicated, or may be provided by other devices or systems at the same time. In some embodiments, the server 110 may be regional or remote. In some embodiments, the server 110 may be implemented on a cloud platform or provided in a virtual manner. By way of example only, a cloud platform may include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, an internal cloud, a multi-layer cloud, or the like, or any combination thereof.

[0052] In some embodiments, the network 130 may be any one or more of a wired network or a wireless network. For example, the network 130 may include a local area network (LAN), a wide area network (WAN), a wireless local area network (WLAN), a metropolitan area network (MAN), etc. or any combination thereof.

[0053] For ease of understanding, the technical solution of the present application is introduced below in conjunction with the accompanying drawings and embodiments.

[0054] Figure 2A It is an exemplary schematic diagram of a viscosity reduction system for oilfield produced fluid according to some embodiments of the present application.

[0055] like Figure 2A As shown, the viscosity reduction system of oilfield produced fluid provided in the embodiment of the present application includes: a first oil collecting pipe, a water-injection pipe and a second oil collecting pipe. The water-injection pipe is connected to the first oil collecting pipe at a first connection point, one end of the second oil collecting pipe is connected to the first oil collecting pipe between the oil well and the first connection point at a second connection point, and the other end of the second oil collecting pipe is connected to the first oil collecting pipe at a third connection point, and the third connection point is located in the direction of the first connection point away from the oil well (the meaning of away from the oil well is the side of the first oil collecting pipe away from the oil well, that is, the downstream of the first oil collecting pipe).

[0056] The second connection point is configured to split the oilfield produced fluid into the first oil collecting pipe and the second oil collecting pipe; the oilfield produced fluid in the first oil collecting pipe is recorded as the first produced fluid, and the oilfield produced fluid in the second oil collecting pipe is recorded as the second produced fluid;

[0057] The first connection point is configured to evenly mix the first produced liquid and the water in the water-injection pipeline, and the liquid mixed at the first connection point is recorded as a first mixed liquid;

[0058] The third connection point is configured to mix the first mixed liquid and the second produced liquid evenly, and the liquid mixed at the third connection point is recorded as the second mixed liquid.

[0059] Exemplarily, the first connection point is configured to allow the first mixed liquid to flow along the first oil collecting pipe to the third connection point;

[0060] The third connection point is configured to allow the second mixed liquid to flow out along the first oil collecting pipe in a direction away from the first connection point.

[0061] Exemplarily, the ratio of the length of the pipeline between the first connection point and the second connection point to the length of the pipeline between the first connection point and the third connection point is 1:(1 to 2);

[0062] Exemplarily, the ratio of the diameters of the first oil pipe and the second oil collecting pipe is 1:(2 to 5).

[0063] Exemplarily, the first oil collecting pipe is made of a hydrophilic material.

[0064] Figure 3 is an exemplary flow chart of a method for reducing the viscosity of oilfield produced fluid according to some embodiments of the present application. The method for reducing the viscosity of oilfield produced fluid is applied to Figure 2A The viscosity reduction system of oilfield produced fluid shown in FIG. Figure 3 As shown, the method for reducing the viscosity of oilfield produced fluid includes the following steps.

[0065] Step S310, obtaining multiple groups of first data to be fitted, obtaining the oil-water transition water content of the oilfield produced fluid according to the multiple groups of first data to be fitted, and fitting to obtain the water-in-oil upward curve of the oilfield produced fluid.

[0066] The oil-water transition water content of the oilfield produced fluid and the water-in-oil upward curve of the oilfield produced fluid can also be directly obtained by measurement.

[0067] The fitting method may be:

[0068] The first data to be fitted include different water contents and corresponding viscosity values ​​of the oilfield produced fluid when the produced fluid is in a water-in-oil state.

[0069] Oilfield produced fluid, which is an oil-water mixture, includes two states: water-in-oil state (when the water content is low) and oil-in-water state (when the water content is high).

[0070] In some embodiments, multiple groups of first data to be fitted can be obtained by the following method: after successively adding a preset amount of water to the first test crude oil, the mixed liquid is measured to obtain each group of first data to be fitted. The first test crude oil is a crude oil with a water content lower than the first preset threshold value and in an oil-in-water state. For example, a small amount of oilfield produced liquid can be collected from an oil well as the first test crude oil. For another example, a crude oil with a lower water content and the same physical properties as the oilfield produced liquid can be used as the first test crude oil. The first preset threshold value is a value slightly higher than the water content of the oilfield produced liquid. For example, if the water content of the oilfield produced liquid is 55%, the first preset threshold value can be 60%. In the specific implementation process, a variety of methods can be used to obtain the water content of the mixed liquid, such as distillation, electro-desorption, etc. The viscosity of crude oil can be a measure of the friction resistance when a certain part of the crude oil flows relative to another part, and the unit of viscosity is mPa·s. In the specific implementation process, a variety of methods can be used to measure the viscosity value of crude oil, such as dynamic viscosity measurement, kinematic viscosity measurement, and conditional viscosity measurement.

[0071] In the specific implementation process, a preset amount of water can be added to the first test crude oil in succession, so that the water content of the mixed liquid after each water addition increases by 2 to 5 percentage points compared with that before water addition. After each water addition, the first test crude oil and water are stirred evenly, and the mixed liquid is tested to obtain the water content and viscosity value of the mixed liquid as a set of first data to be fitted.

[0072] In some embodiments, the preset water addition amount can be obtained by: calculating the first product between the first volume and the first water content difference; wherein the first volume is the volume of the mixed liquid of the first test crude oil before the i-th water addition, and the first water content difference is the difference between the water content of the mixed liquid of the first test crude oil after the i-th water addition and the water content of the mixed liquid of the first test crude oil after the i-1-th water addition, i is an integer greater than 0; calculating the difference between 1 and the water content of the mixed liquid of the first test crude oil after the i-th water addition as the first difference; calculating the ratio between the first product and the first difference, and obtaining the preset water addition amount when water is added to the first test crude oil for the i-th time. The calculation formula is as follows:

[0073]

[0074] In formula (1), m i V is the preset water content of the first test crude oil added with water for the ith time; i-1 is the first volume, i.e., the volume of the mixed liquid of the first test crude oil before the i-th addition of water; and are the water content of the mixed liquid after the i-th water addition of the first test crude oil and the water content of the mixed liquid after the i-1-th water addition of the first test crude oil, Can be Difference Δφ from the first moisture content i The first moisture content difference Δφ is obtained by summing the values ​​of i Can be set by the tester, Δφ i ∈[2%, 5%]. In the specific implementation process, the total number of times water is added to the first test crude oil can be recorded as I, and I can be between 29 and 49. After the last water addition, It can be between 85% and 95%.

[0075] The above method obtains the preset water amount added to the test crude oil each time by volume percentage. In some embodiments, other methods (for example, by weight percentage) can also be used to obtain the preset water amount added to the first test crude oil each time, which is not limited to the description of this application.

[0076] In the above test process, in addition to obtaining multiple sets of first data to be fitted, the oil-water transition water cut can also be obtained. The oil-water transition water cut is the water cut corresponding to the maximum viscosity value in the multiple sets of first data to be fitted.

[0077] After obtaining multiple sets of first data to be fitted, the water-in-oil upward curve of the oilfield produced fluid can be fitted according to the multiple sets of first data to be fitted. The water-in-oil upward curve of the oilfield produced fluid is a relationship curve between the water content and the viscosity value of the oilfield produced fluid when the water content of the oilfield produced fluid gradually increases in the water-in-oil state.

[0078] In some embodiments, the water content of the oilfield produced fluid can be used as an independent variable, and the viscosity of the oilfield produced fluid can be used as a dependent variable to construct a one-variable multi-time equation. The one-variable multi-time equation is as follows:

[0079]

[0080] In formula (2), is the viscosity value corresponding to different water contents of the produced fluid in the oil-in-water state; Φ is the water content of the produced fluid, φ * is the water content of oil-water transition, when Φ≤φ * When , the oilfield produced fluid is in the water-in-oil state; a, b and c are fitting parameters; η o It is the viscosity value of the crude oil tested without adding water.

[0081] In some embodiments, the above-mentioned one-variable multi-time equation can be solved based on multiple sets of first data to be fitted to determine the fitting parameters of the one-variable multi-time equation. * Substitute the moisture content and viscosity data at 100 °C into formula (2), use the least squares method to solve formula (2), and determine the values ​​of the fitting parameters (a, b, c).

[0082] In some embodiments, the water-in-oil upward curve can be obtained by plotting the univariate multi-order equation with determined fitting parameters in a rectangular coordinate system. For example, multiple sets of coordinates (including x-coordinates and y-coordinates) can be obtained according to formula (2), and multiple scattered points corresponding to the multiple sets of coordinates can be plotted in a rectangular coordinate system, and then the multiple scattered points can be connected by a curve to obtain the following: Figure 4 The water-in-oil upward curve a is shown.

[0083] In the specific implementation process, when the water content of the first test crude oil and water mixture is greater than the oil-water transition water content, the mixture is in the water-in-oil state, and water is continuously added to the mixture, so that multiple sets of water content and viscosity value data of oilfield produced fluid in the water-in-oil state can be obtained. In some embodiments, the following one-variable multi-time equation can be constructed based on the physical properties of the oilfield produced fluid in the water-in-oil state:

[0084]

[0085] In formula (3), is the viscosity value corresponding to different water contents of the oilfield produced fluid in the water-in-oil state; Φ is the water content of the oilfield produced fluid, φ * is the water content of oil-water transition, when Φ>φ * When , the produced fluid of the oil field is in the state of oil in water; d, f, g and h are fitting parameters.

[0086] In some embodiments, multiple sets of water content and viscosity data of oilfield produced fluids in a water-in-oil state can be used to solve (for example, using the least squares method) the above-mentioned one-variable multivariate equation to determine the fitting parameters of the one-variable multivariate equation.

[0087] In some embodiments, the water-in-oil upward curve can be obtained by plotting it in a plane rectangular coordinate system according to a one-variable multi-time equation with determined fitting parameters. For example, according to formula (3), multiple sets of coordinates (including x-coordinates and y-coordinates) can be obtained, and multiple scattered points corresponding to the multiple sets of coordinates can be plotted in a plane rectangular coordinate system, and then the multiple scattered points can be connected with a curve to obtain the following: Figure 4 The oil-in-water upward curve b is shown.

[0088] Step S320, obtaining multiple sets of second data to be fitted, and fitting the water-in-water downward curve of the oilfield produced fluid according to the multiple sets of second data to be fitted.

[0089] The water-in-oil downward curve of the oilfield produced fluid can also be directly obtained through measurement.

[0090] The second data to be fitted include different water contents and corresponding viscosity values ​​when the oilfield produced fluid is in the water-in-oil state. In some embodiments, multiple groups of second data to be fitted can be obtained by the following method: after the water-free crude oil with a preset oil content is successively added to the second test crude oil, each group of second data to be fitted is obtained by measuring the mixed liquid. The second test crude oil is a crude oil in the water-in-oil state with a water content higher than the second preset threshold value (which can be a value greater than the water content of the oil-water transition). In the specific implementation process, after the water-addition test of the first test crude oil in step S210 is completed, the mixed liquid of the first test crude oil and water in the water-in-oil state can be used as the second test crude oil, and the water-free crude oil with a preset oil content is successively added, so that the water content of the mixed liquid of the second test crude oil and water after the water-free crude oil is added is reduced by 2 percentage points to 5 percentage points compared with the water-free crude oil before the water-free crude oil is added. After each addition of water-free crude oil, the second test crude oil and the water-free crude oil are stirred evenly, and the water content and viscosity value of the mixed liquid are tested to obtain a group of second data to be fitted.

[0091] In some embodiments, the preset oil blending amount can be obtained by:

[0092] The second product between the second volume and the second water content difference is calculated; wherein the second volume is the volume of the mixed liquid before the second test crude oil is blended with the water-free crude oil for the jth time, and the second water content difference is the difference between the water content of the mixed liquid after the second test crude oil is blended with the water-free crude oil for the j-1th time and the water content of the mixed liquid after the second test crude oil is blended with the water-free crude oil for the jth time, and j is an integer greater than 0; the ratio between the second product and the water content of the mixed liquid after the jth blending with the water-free crude oil is calculated to obtain the preset blending amount when the water-free crude oil is blended with the second test crude oil for the jth time, and the calculation formula is as follows:

[0093]

[0094] In formula (4), n j W is the preset amount of anhydrous crude oil added to the second test crude oil for the jth time; j-1 is the second volume, i.e., the volume of the mixture of the second test crude oil and the anhydrous crude oil before the jth addition of the anhydrous crude oil; j and λ j-1 are the water content of the mixed liquid after the jth addition of anhydrous crude oil and the water content of the mixed liquid after the j-1th addition of anhydrous crude oil, respectively, j It can be represented by j-1 The difference between the second moisture content and i The second moisture content difference Δλ is obtained by subtracting j Can be set by the tester, Δλ j ∈[2%, 5%], λ0 is equal to the total number of times water is added to the test crude oil in formula (1) when i is equal to I

[0095] The above method obtains the preset amount of anhydrous crude oil blended into the test crude oil each time by volume percentage. In some embodiments, other methods (for example, by weight percentage) may also be used to obtain the preset amount of anhydrous crude oil blended into the second test crude oil each time, which is not limited to the description of this specification.

[0096] After obtaining multiple sets of second data to be fitted, the water-in-oil downward curve of the oilfield produced fluid can be fitted according to the multiple sets of second data to be fitted. The water-in-oil downward curve of the oilfield produced fluid is a relationship curve between the water content and the viscosity value of the oilfield produced fluid when the water content of the oilfield produced fluid gradually decreases in the water-in-oil state.

[0097] In some embodiments, the water content of the oilfield produced fluid can be used as an independent variable, and the viscosity of the oilfield produced fluid can be used as a dependent variable to construct a one-variable multi-time equation. The one-variable multi-time equation is as follows:

[0098]

[0099] In formula (5), is the viscosity value corresponding to different water contents of the produced fluid in the water-in-oil state; Φ is the water content of the produced fluid; p, q, r and s are fitting parameters.

[0100] In some embodiments, the above-mentioned one-variable multi-time equation can be solved based on multiple sets of second data to be fitted to determine the fitting parameters of the one-variable multi-time equation. For example, the water content and viscosity value data in the multiple sets of second data to be fitted can be substituted into formula (5), and the least squares method can be used to solve formula (5) to determine the values ​​of the fitting parameters (p, q, r and s).

[0101] In some embodiments, the water-in-oil downward curve can be obtained by plotting it in a plane rectangular coordinate system according to a one-variable multi-time equation with determined fitting parameters. For example, according to formula (5), multiple sets of coordinates (including x-coordinates and y-coordinates) can be obtained, and multiple scattered points corresponding to the multiple sets of coordinates can be plotted in a plane rectangular coordinate system, and then the multiple scattered points can be connected by a curve to obtain the following: Figure 4 The downward curve c of oil-in-water content is shown.

[0102] Step S330: taking the water content corresponding to the intersection of the water-in-oil upward curve and the oil-in-water downward curve as the critical water content.

[0103] like Figure 4 As shown, when the water content of the oilfield produced fluid is between the water content corresponding to the intersection of the oil-in-water water content upward curve a and the water-in-oil water content downward curve c, and the oil-water transition water content, the water-in-oil water content downward curve c is relatively gentle, that is, the water content of the oilfield produced fluid is greatly reduced within this interval, and the viscosity value of the oilfield produced fluid changes little. Therefore, the water content corresponding to the intersection of the oil-in-water water content upward curve and the water-in-oil water content downward curve can be used as the critical water content. Just as an example, Figure 4 In the water-in-oil downward curve c shown, the water content at point D is 71%, and its viscosity value is the same as that at point B (water content 81%), both of which are 140 mPa·s.

[0104] Step S340, based on the critical water cut and the oil-water transition water cut, determine the flow value of the first produced liquid in the first oil collecting pipe, the flow value of the water in the water blending pipeline, and the flow value of the second produced liquid in the second oil collecting pipe to meet the set conditions, the set conditions include that the water content of the first mixed liquid is higher than the oil-water transition water cut, the water content of the second mixed liquid is higher than the critical water cut, and is lower than the oil-water transition water cut.

[0105] In some embodiments, the flow value of the first produced fluid in the first oil collecting pipe, the flow value of the water in the water mixing pipe, and the flow value of the second produced fluid in the second oil collecting pipe can be determined based on the critical water content, the oil-water transition water content, the production value and water content of the oilfield produced fluid in the oil well, the set conditions, and the target viscosity value to be achieved. The relationship between the flow value of the first produced fluid and the flow value of the second produced fluid can be expressed by the formula:

[0106] x1+x2=Z (6)

[0107] In formula (6), x1 is the variable corresponding to the flow value of the first produced fluid, x2 is the variable corresponding to the flow value of the second produced fluid, and Z is the production value of the oil well that collects the produced fluid of the oil field. There are multiple value options for x1 and x2.

[0108] The relationship between the flow rate of the first produced liquid, the flow rate of the second produced liquid and the flow rate of water in the water mixing pipeline can be expressed by the formula:

[0109]

[0110] In formula (7), x1 is the variable corresponding to the flow value of the first produced liquid, x2 is the variable corresponding to the flow value of the second produced liquid, and x3 is the variable corresponding to the flow value of the water in the water injection pipeline. is the critical moisture content, is the water content of oil-water transition, a is the water content of oilfield produced fluid. There are many options for x1, x2 and x3.

[0111] In the specific implementation process, multiple groups of numerical combinations of the flow value of the first produced liquid, the flow value of the second produced liquid, and the flow value of the water in the water-injection pipeline can be obtained according to formulas (6) and (7). According to the target viscosity value to be achieved, one group can be selected from the multiple numerical combinations as the actual flow value of the first produced liquid, the flow value of the second produced liquid, and the flow value of the water in the water-injection pipeline. For example, the values ​​of the first flow produced liquid, the flow value of the second produced liquid, and the flow value of the water in the water-injection pipeline in the multiple numerical combinations can be used respectively to calculate multiple water contents of the second mixed liquid in the first oil collecting pipe according to formula (7), and then refer to Figure 4 The water-in-oil downward curve c shown in FIG. 1 is used to determine the water content (e.g., 71%) corresponding to the target viscosity value to be achieved (e.g., 140 mPa·s) from the multiple water contents, and the flow value of the first produced fluid, the flow value of the second produced fluid, and the flow value of water in the water-injection pipeline in the numerical combination of the water content are calculated as the flow value of the first produced fluid, the flow value of the second produced fluid, and the flow value of water in the water-injection pipeline actually used.

[0112] As an example, the production of a certain oil well is 40m 3 / d (cubic meters / day), the water content of the oil field produced in the oil well is 55%, which is an oil-in-water emulsion with a viscosity of 610mPa·s. Figure 4 In order to meet the subsequent gathering and transportation requirements, the viscosity of the produced fluid after water addition needs to be reduced to 140 mPa·s.

[0113] The viscosity of the produced fluid under different water contents is shown in Table 1.

[0114] Table 1 Viscosity of produced fluid at different water contents

[0115]

[0116]

[0117] When the water content is tested, as shown in Table 1, when the water content is 74%, the maximum viscosity value is 1292mPa·s, that is, the oil-water transition water content Φ * It is 74%.

[0118] According to the data in Table 1, the fitting result is:

[0119] Water-in-oil upward curve:

[0120]

[0121] Oil-in-water upward curve:

[0122]

[0123] Oil-in-water downward curve:

[0124]

[0125] Solving equations (8) and (10) simultaneously, we can obtain the critical moisture content: It is 51%.

[0126] As an example, the production of a certain oil well is 40m 3 / d (cubic meters / day), the water content of the oil field produced in the oil well is 55%, which is an oil-in-water emulsion with a viscosity of 610mPa·s. Figure 4 As shown in point A.

[0127] The existing process adopts a one-time mixing method, such as Figure 2B As shown in the figure, each oil well is equipped with an oil gathering pipeline and a water injection pipeline. The oil gathering pipeline is used to transport the oilfield produced fluid in the oil well, and the water injection pipeline is used to inject a large amount of water into the oil gathering pipeline. The flow rate injected into the oil gathering pipeline through the water injection pipeline is 54.7m 3 / d of water, the water content of the oilfield produced fluid in the oil gathering pipeline increased to 81%, which is higher than the oil-water transformation water content of 74%. The oilfield produced fluid in the oil gathering pipeline is transformed into an oil-in-water emulsion, and its viscosity is reduced to 140mPa·s. Figure 4 As shown by point B in the figure. Each oil well is equipped with an oil gathering pipeline and a water mixing pipeline. The oil gathering pipeline is used to transport the oilfield produced fluid in the oil well, and the water mixing pipeline is used to inject a large amount of water into the oil gathering pipeline. Let (9) be equal to 140mPa·s, and solve it to get the water content after one mixing is 81%, as shown in Figure 4 As shown in point B in the figure. It is known that the current production of oilfield produced fluid in the oil well is 40m 3 / d, the moisture content is 55%, then the amount of water added when using the one-time mixing method is 40×(81%-55%)÷(1-81%)=54.7m 3 / d.

[0128] The embodiments provided in this application are applied to Figure 2A In the oilfield produced fluid viscosity reduction system shown in FIG, each oil well is provided with two oil gathering pipelines: the first oil gathering pipeline, the second oil gathering pipeline, and a water mixing pipeline, and a two-time mixing method is adopted, such as Figure 2A shown.

[0129] The distance between the first connection point and the second connection point is 2m, and the distance between the first connection point and the third connection point is 3m, with a ratio of 2:3. The diameter of the first oil collecting pipe is 50mm, and the diameter of the second oil collecting pipe is 150mm, with a ratio of 1:3.

[0130] By using formula (6) and formula (7), the flow rate of the first produced liquid, the flow rate of the second produced liquid and the flow rate of water in the water injection pipeline can be determined as follows: 11m 3 / d, 29m 3 / d, 22.1m 3 / d.

[0131] Assuming that equation (10) is equal to 140 mPa·s, the solution is that the water content of the second mixed liquid is 71%, and 51%≤71%≤74%, which satisfies the requirement of equation (7).

[0132] The current production of produced fluid from the known oil well is 40m 3 / d, the water content is 55%, the flow rate of water in the water mixing pipeline is calculated as: 40×(71%-55%)÷(1-71%)=22.1m 3 / d;

[0133] Assuming the water content of the first mixed liquid is 85%, the flow rate of the first produced liquid is: 22.1×(1-85%)÷(85%-55%)=11m 3 / d, the flow rate of the second produced liquid is: 40-11=29m 3 / d.

[0134] Set the flow rate of the first produced liquid in the first oil collecting pipe to 11m 3 / d, the flow rate of water in the water mixing pipeline is set to 22.1m 3 / d (third flow value), such as Figure 2A As shown in the figure, the water in the water-injected pipeline is injected into the first oil collecting pipe at the first connection point, and the flow value is 33.1m 3 / d of the first mixed liquid in the first oil collecting pipe, the water content of the first mixed liquid is 85%, which is higher than the water content of the oil-water transition of 74%, and is an oil-in-water emulsion. Figure 4 As shown in point C in FIG. Compared with the first produced fluid, the viscosity of the first mixed fluid is greatly reduced, and the friction resistance between the first mixed fluid and the oil gathering pipeline is greatly reduced.

[0135] Set the flow rate of the second produced fluid in the second oil collecting pipe to 29m 3 / d, such as Figure 2A As shown, the second produced fluid in the second oil collecting pipe is injected into the first oil collecting pipe at the third connection point, and the flow value is 62.1m 3 / d of the second mixed liquid in the first oil collecting pipe, the second mixed liquid is still an oil-in-water emulsion with a viscosity of 140 mPa·s.

[0136] The second mixed liquid is obtained by treating the first produced liquid in the first oil collecting pipe, the water in the water-mixing pipe, and the second produced liquid in the second oil collecting pipe using the secondary mixing method provided in the embodiment of the present application. The viscosity values ​​of the first produced liquid in the first oil collecting pipe and the second produced liquid in the second oil collecting pipe are both 610 mPa·s, and the viscosity value of the second mixed liquid in the first oil collecting pipe is reduced to 140 mPa·s (the same as the viscosity value of the oilfield produced liquid in the oil collecting pipe after being treated by the existing process). The amount of water added is increased from 54.7 mPa·s required by the existing process to 140 mPa·s. 3 / d decreased to 22.1m 3 / d, the reduction ratio reached 59.7%; and the flow value of the second mixed liquid in the first oil collecting pipe was reduced from 94.7m 3 / d decreased to 62.1m 3 / d, the reduction ratio reaches 34.5%. If the first oil collecting pipe is in laminar flow, the friction resistance between the second mixed liquid in the first oil collecting pipe and the pipe can be reduced by 34.5% compared with the mixed liquid in the oil collecting pipe obtained by the one-time mixing method of the existing process. If the first oil collecting pipe is in a hydraulic smooth area, the friction resistance between the second mixed liquid in the first oil collecting pipe and the pipe can be reduced by 52.2% compared with the mixed liquid in the oil collecting pipe obtained by the one-time mixing method of the existing process.

[0137] In summary, the embodiment provided in the present application obtains a second mixed liquid with lower viscosity and lower water content in the first oil collecting pipe through a secondary mixing method, thereby reducing the transportation cost of the oil field produced liquid while reducing the viscosity of the oil field produced liquid in the oil collecting pipeline.

[0138] Step S350, according to the flow value of the first produced liquid in the first oil collecting pipe, the flow value of water in the water blending pipe and the flow value of the second produced liquid in the second oil collecting pipe, the viscosity reduction system of the oil field produced liquid is used to reduce the viscosity of the oil field produced liquid.

[0139] In the specific implementation process, according to the flow value of the first produced liquid in the first oil collecting pipe, the flow value of the water in the water blending pipeline, and the flow value of the second produced liquid in the second oil collecting pipe obtained in step S340, the following settings can be respectively made: Figure 2A The flow rates of the first oil collecting pipe, the water blending pipe and the second oil collecting pipe in the viscosity reduction system of the oilfield produced fluid are shown.

[0140] Figure 5 It is an exemplary schematic diagram of a viscosity reduction device for oilfield produced fluid according to some embodiments of the present application.

[0141] like Figure 5 As shown, the viscosity reduction device for oilfield produced fluid includes: a first fitting module 510 , a second fitting module 520 , a critical water content obtaining module 530 , a flow value determining module 540 and a viscosity reduction module 550 .

[0142] The first fitting module 510 is used to obtain multiple groups of first data to be fitted, obtain the oil-water transition water cut according to the multiple groups of the first data to be fitted, and fit the water-in-oil upward curve of the oilfield produced fluid; wherein the first data to be fitted include different water cuts and corresponding viscosity values ​​of the oilfield produced fluid when it is in an oil-in-water state, and the oil-water transition water cut is the water cut corresponding to the maximum viscosity value in the multiple groups of the first data to be fitted.

[0143] The second fitting module 520 is used to obtain multiple groups of second data to be fitted, and fit the water-in-oil downward curve of the oilfield produced fluid according to the multiple groups of the second data to be fitted; wherein the second data to be fitted include different water contents and corresponding viscosity values ​​of the oilfield produced fluid when it is in a water-in-oil state.

[0144] The critical water content obtaining module 530 is used to take the water content corresponding to the intersection of the water-in-oil upward curve and the oil-in-water downward curve as the critical water content.

[0145] The flow value determination module 540 is used to determine the flow value of the first produced liquid in the first oil collecting pipe, the flow value of the water in the water blending pipeline, and the flow value of the second produced liquid in the second oil collecting pipe according to the critical water cut and the oil-water transition water cut, so as to meet the set conditions, wherein the set conditions include that the water content of the first mixed liquid is higher than the oil-water transition water cut, and the water content of the second mixed liquid is higher than the critical water cut and lower than the oil-water transition water cut.

[0146] It is also possible to combine the above flow values ​​and set the temperature of the first oil collecting pipe so as not to affect the water content of the first mixed liquid being higher than the oil-water transition water content, and set the temperature of the second oil collecting pipe so as not to affect the water content of the second mixed liquid being higher than the critical water content and lower than the oil-water transition water content.

[0147] The viscosity reduction module 550 is used to reduce the viscosity of the oilfield produced fluid through the oilfield produced fluid viscosity reduction system according to the flow value of the first produced fluid in the first oil collecting pipe, the flow value of water in the water mixing pipeline and the flow value of the second produced fluid in the second oil collecting pipe.

[0148] In the above-mentioned embodiment of the viscosity reduction device for oilfield produced fluid, the specific processing of each module and the technical effects brought about by it can be referred to the relevant description in the corresponding method embodiment, which will not be repeated here.

[0149] Figure 6 It is a schematic diagram of an exemplary structure of an electronic device according to some embodiments of the present application.

[0150] like Figure 6 As shown, the electronic device includes: at least one processor 601, at least one communication interface 602, at least one memory 603 and at least one communication bus 604; optionally, the communication interface 602 can be an interface of a communication module, such as an interface of a GSM module; the processor 601 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 invention. The memory 603 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 603 stores a program, and the processor 601 calls the program stored in the memory 603 to execute part or all of the above-mentioned method embodiments.

[0151] 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 application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0152] At the same time, the present application uses specific words to describe the embodiments of the present application. 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 application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or multiple times in different positions in the present application does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0153] In addition, unless explicitly stated in the claims, the order of the processing elements and sequences described in this application, the use of alphanumeric characters, or the use of other names are not intended to limit the order of the processes and methods of this application. 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 this application. 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.

[0154] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this application, 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 this application 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.

[0155] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of 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 their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0156] Each patent, patent application, patent application disclosure, and other materials, such as articles, books, instructions, publications, documents, etc., cited in this application are hereby incorporated by reference in their entirety. Except for application history documents that are inconsistent with or conflicting with the content of this application, documents that limit the broadest scope of the claims of this application (currently or later attached to this application) are also excluded. It should be noted that if the descriptions, definitions, and / or use of terms in the attached materials of this application are inconsistent or conflicting with the content described in this application, the descriptions, definitions, and / or use of terms in this application shall prevail.

[0157] Finally, it should be understood that the embodiments described in this application are only used to illustrate the principles of the embodiments of the present application. Other variations may also fall within the scope of the present application. Therefore, as an example and not a limitation, the alternative configurations of the embodiments of the present application may be considered to be consistent with the teachings of the present application. Accordingly, the embodiments of the present application are not limited to the embodiments explicitly introduced and described in the present application.

Claims

1. A viscosity reduction system for oilfield produced fluid, characterized in that: The system comprises: a first oil collecting pipe, a water mixing pipe and a second oil collecting pipe; wherein, The water injection pipeline is connected to the first oil collecting pipe at a first connection point, one end of the second oil collecting pipe is connected to the first oil collecting pipe between the oil well and the first connection point at a second connection point, and the other end of the second oil collecting pipe is connected to the first oil collecting pipe at a third connection point, and the third connection point is located in the direction of the first connection point away from the oil well; The second connection point is configured to split the oilfield produced fluid into the first oil collecting pipe and the second oil collecting pipe; the oilfield produced fluid in the first oil collecting pipe is recorded as the first produced fluid, and the oilfield produced fluid in the second oil collecting pipe is recorded as the second produced fluid; The first connection point is configured to evenly mix the first produced liquid and the water in the water-injection pipeline; the liquid mixed at the first connection point is recorded as a first mixed liquid; The third connection point is configured to mix the first mixed liquid and the second produced liquid evenly, and the liquid mixed at the third connection point is recorded as the second mixed liquid.

2. The viscosity reduction system according to claim 1, characterized in that: The first connection point is configured to allow the first mixed liquid to flow along the first oil collecting pipe to the third connection point; The third connection point is configured to allow the second mixed liquid to flow out along the first oil collecting pipe in a direction away from the first connection point.

3. The viscosity reduction system according to claim 1 or 2, characterized in that: The first oil collecting pipe is made of hydrophilic material.

4. The viscosity reduction system according to claim 1 or 2, characterized in that: The ratio of the length of the pipeline between the first connection point and the second connection point to the length of the pipeline between the first connection point and the third connection point is 1:(1 to 2); Optionally, the ratio of the diameters of the first oil collecting pipe and the second oil collecting pipe is 1:(2 to 5).

5. A method for reducing the viscosity of oilfield produced fluid, characterized in that: The viscosity reduction system for oilfield produced fluid according to any one of claims 1 to 4 is used, and the method comprises: Measuring or fitting the oil-water transition water content of the oilfield produced fluid; Measuring or fitting the first viscosity value and the corresponding first water content of the oilfield produced fluid when the water content gradually increases under the water-in-oil condition, measuring the second viscosity value and the second water content of the oilfield produced fluid when the water content gradually decreases under the oil-in-water condition, and taking the water content when the first water content and the second water content are equal and the first viscosity value and the second viscosity value are equal as the critical water content; According to the critical water content and the oil-water transition water content, determine the flow value of the first produced liquid in the first oil collecting pipe, the flow value of the water in the water mixing pipe, and the flow value of the second produced liquid in the second oil collecting pipe to meet the set conditions, wherein the set conditions include that the water content of the first mixed liquid is higher than the oil-water transition water content, and the water content of the second mixed liquid is higher than the critical water content and lower than the oil-water transition water content; According to the flow value of the first produced liquid in the first oil collecting pipe, the flow value of water in the water mixing pipe and the flow value of the second produced liquid in the second oil collecting pipe, the viscosity reduction system of the oil field produced liquid is used to reduce the viscosity of the oil field produced liquid.

6. The method according to claim 5, characterized in that The method of determining the flow value of the first produced liquid in the first oil collecting pipe, the flow value of the water in the water blending pipeline, and the flow value of the second produced liquid in the second oil collecting pipe according to the critical water content and the oil-water transition water content includes: Based on the critical water cut, the oil-water transition water cut, the production value and water cut of the oilfield produced fluid in the oil well, the set conditions and the target viscosity value to be achieved, the flow value of the first produced fluid in the first oil collecting pipe, the flow value of the water in the water injection pipe and the flow value of the second produced fluid in the second oil collecting pipe are determined.

7. The method according to claim 5, characterized in that The viscosity of the oilfield produced fluid in the viscosity reduction method is 10mPa.s to 2000mPa.s; Optionally, the water content of the oilfield produced fluid does not exceed 75wt.%.

8. The method according to any one of claims 5 to 7, characterized in that The temperature of the first oil collecting pipe is set so as not to affect the water content of the first mixed liquid being higher than the oil-water transition water content, and the temperature of the second oil collecting pipe is set so as not to affect the water content of the second mixed liquid being higher than the critical water content and lower than the oil-water transition water content.

9. The method according to any one of claims 5 to 7, characterized in that Controlling the flow ratio of the first produced liquid to the second produced liquid to be 10:(11 to 100); The flow ratio of the first produced fluid to the water is controlled to be 10:(13 to 50).

10. The method according to any one of claims 5 to 7, characterized in that The viscosity reduction method does not use a flow modifier.

11. A viscosity reducing device for oilfield produced fluid, characterized in that: The device comprises: A first fitting module is used to obtain multiple groups of first data to be fitted, obtain the oil-water transition water cut according to the multiple groups of the first data to be fitted, and fit the water-in-oil upward curve of the oilfield produced fluid; wherein the first data to be fitted include different water cuts and corresponding viscosity values ​​of the oilfield produced fluid when it is in the water-in-oil state, and the oil-water transition water cut is the water cut corresponding to the maximum viscosity value among the multiple groups of the first data to be fitted; A second fitting module is used to obtain multiple groups of second data to be fitted, and to fit the water-in-oil downward curve of the oilfield produced fluid according to the multiple groups of the second data to be fitted; wherein the second data to be fitted include different water contents and corresponding viscosity values ​​of the oilfield produced fluid when it is in the water-in-oil state; A critical water content obtaining module, used to take the water content corresponding to the intersection of the water-in-oil upward curve and the oil-in-water downward curve as the critical water content; a flow value determination module, for determining the flow value of the first produced liquid in the first oil collecting pipe, the flow value of the water in the water blending pipeline, and the flow value of the second produced liquid in the second oil collecting pipe according to the critical water cut and the oil-water transition water cut, so as to meet the set conditions, wherein the set conditions include that the water cut of the first mixed liquid is higher than the oil-water transition water cut, and the water cut of the second mixed liquid is higher than the critical water cut and lower than the oil-water transition water cut; The viscosity reduction module is used to reduce the viscosity of the oilfield produced liquid through the oilfield produced liquid viscosity reduction system according to the flow value of the first produced liquid in the first oil collecting pipe, the flow value of the water in the water mixing pipeline and the flow value of the second produced liquid in the second oil collecting pipe.

12. 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 5 to 10 when running the computer program.

13. A storage device for storing a computer-readable program, wherein when the computer-readable program is executed, the method according to any one of claims 5 to 10 is executed.

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