A viscosity reduction system, method, device and electronic equipment for oilfield produced fluid

Abstract

The embodiment of the present application provides a kind of oilfield produced liquid viscosity reduction system, method, device, electronic equipment, the oilfield produced liquid viscosity reduction system includes: first oil collecting pipe, water mixing pipeline and second oil collecting pipe;Wherein, the water mixing pipeline is communicated with the first connecting point at the first oil collecting pipe, one end of the second oil collecting pipe is communicated with the first oil collecting pipe between oil well and the first connecting point at the second connecting point, the other end of the second oil collecting pipe is communicated with the first oil collecting pipe at the third connecting point, and the third connecting point is located in the direction of the first connecting point away from oil well.This application provides viscosity reduction system, can use secondary mixing method, can reduce the viscosity of oilfield produced liquid in oil collecting pipeline, reduce the transportation cost of oilfield produced liquid.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to, but is not limited to, the field of oilfield gathering and transportation, and in particular, but not exclusively, to a viscosity reduction system, method, device and electronic device for oilfield produced fluid. BACKGROUND

[0002] In the early stage of crude oil production, the water content of the oilfield produced fluid obtained from the oil well is low (water content of the oilfield produced fluid < 20 vol.%), and as the crude oil production 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 period (20 vol.% ≤ water content of the oilfield produced fluid < 60 vol.%), the oilfield produced fluid is prone to become a water-in-oil emulsion, thus causing the viscosity of the oilfield produced fluid to increase sharply.

[0003] Generally, a large amount of water is mixed into the oil gathering pipeline at one time to convert the oilfield produced fluid from a water-in-oil emulsion (high viscosity) to an oil-in-water emulsion (low viscosity), thereby reducing the frictional resistance of transportation. However, this one-time oil-water mixing method requires a large amount of water resources, thus resulting in high transportation cost of the oilfield produced fluid.

[0004] Therefore, how to reduce the viscosity of the oilfield produced fluid in the oil gathering pipeline while reducing the transportation cost of the oilfield produced fluid is a technical problem to be solved. SUMMARY

[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 disclosure exemplarily provides a viscosity reduction system for oilfield produced fluid, the system comprising: a first oil gathering pipeline, a water mixing pipeline and a second oil gathering pipeline; wherein,

[0007] The water mixing pipeline is in communication with the first oil gathering pipeline at a first connection point, one end of the second oil gathering pipeline is in communication with the first oil gathering pipeline at a second connection point between the oil well and the first connection point, and the other end of the second oil gathering pipeline is in communication with the first oil gathering pipeline at a third connection point, the third connection point being located in the direction away from the oil well of the first connection point;

[0008] The second connection point is configured to divide the oilfield produced fluid into the first oil gathering pipeline and the second oil gathering pipeline; the oilfield produced fluid in the first oil gathering pipeline is referred to as first produced fluid, and the oilfield produced fluid in the second oil gathering pipeline is referred to as second produced fluid;

[0009] The first connection point is configured to mix the first produced fluid and water in the water mixing pipeline uniformly; the mixed liquid after the first connection point is referred to as first mixed liquid;

[0010] The third connection point is configured to mix the first mixture and the second produced fluid evenly, and the liquid after mixing at the third connection point is referred to as the second mixture.

[0011] In one embodiment provided in this application, the first connection point is configured to allow the first mixture to flow along the first oil collection pipe to the third connection point.

[0012] In one embodiment provided in this application, the third connection point is configured such that the second mixture flows out along the first oil collection pipe in a direction away from the first connection point.

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

[0014] In one embodiment provided in this 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 this application, the first oil collecting pipe is made of a hydrophilic material.

[0016] In another aspect, this application provides a method for reducing the viscosity of oilfield produced fluids, using the oilfield produced fluid viscosity reduction system described in any of the above claims, the method comprising:

[0017] Measure or fit the water cut of the oil-water transition of the produced fluid from the oilfield;

[0018] Measure or fit the first viscosity value and the corresponding first water content of the oilfield produced fluid under the oil-in-water condition when the water content gradually increases, measure the second viscosity value and the second water content of the oilfield produced fluid under the water-in-oil condition when the water content gradually decreases, and take 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] Based on the critical water cut and the oil-water transition water cut, the flow rate of the first produced fluid in the first oil gathering pipe, the flow rate of water in the water mixing pipe, and the flow rate of the second produced fluid in the second oil gathering pipe are determined to meet the set conditions. The set conditions include that the water cut of the first mixture is higher than the oil-water transition water cut, and the water cut of the second mixture is higher than the critical water cut and lower than the oil-water transition water cut.

[0020] Based on the flow rate of the first produced fluid in the first oil gathering pipe, the flow rate of water in the water mixing pipe, and the flow rate of the second produced fluid in the second oil gathering pipe, the oilfield produced fluid is subjected to viscosity reduction treatment through the oilfield produced fluid viscosity reduction system.

[0021] In an embodiment provided by the present application, the determining the flow rate value of the first produced fluid in the first gathering pipe, the flow rate value of water in the water mixing pipeline, and the flow rate value of the second produced fluid in the second gathering pipe according to the critical water cut and the oil-water transition water cut comprises:

[0022] The flow rate value of the first produced fluid in the first gathering pipe, the flow rate value of water in the water mixing pipeline, and the flow rate value of the second produced fluid in the second gathering pipe are determined 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 condition, and the target viscosity value to be reached.

[0023] In an embodiment provided by 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 an embodiment provided by the present application, the water cut of the oilfield produced fluid is not more than 75 wt.%.

[0025] In an embodiment provided by the present application, the temperature of the first gathering pipe is set to not affect the water cut of the first mixed fluid being higher than the oil-water transition water cut, and the temperature of the second gathering pipe is set to not affect the water cut of the second mixed fluid being higher than the critical water cut and lower than the oil-water transition water cut.

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

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

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

[0029] In another aspect, the present application provides an electronic device, which comprises a memory and a processor, the memory stores a computer program, and the processor executes the above-mentioned viscosity reduction method of the oilfield produced fluid when running the computer program.

[0030] In another aspect, the present application provides a storage device for storing a computer readable program, which is executed to perform the above-mentioned viscosity reduction method of the oilfield produced fluid.

[0031] The viscosity reduction system of the oilfield produced liquid is composed of the first oil collecting pipe, the water mixing pipeline and the second oil collecting pipe, and a secondary mixing method is adopted: the oilfield produced liquid output by the oil well is divided into the first produced liquid in the first oil collecting pipe and the second produced liquid in the second oil collecting pipe at the second connecting point, the first produced liquid and the water in the water mixing pipeline are mixed at the first connecting point to obtain the first mixed liquid, and the first mixed liquid and the second produced liquid are mixed at the third connecting point to obtain the second mixed liquid with lower viscosity and lower water content, so that the transportation cost of the oilfield produced liquid can be reduced while reducing the viscosity of the oilfield produced liquid in the oil collecting pipeline.

[0032] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present application. Other advantages of the present application will be realized and attained by the solution described in the specification. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings are included to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification, and are used together with the embodiments of the present application to explain the technical solutions of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0034] The present application will be further illustrated in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, the same numbers represent the same structures, wherein:

[0035] Figure 1 is a schematic diagram of an application scene of the viscosity reduction method of the oilfield produced liquid according to some embodiments of the present application.

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

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

[0038] Figure 3 is an exemplary flowchart of the viscosity reduction method of the oilfield produced liquid according to some embodiments of the present application;

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

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

[0041] Figure 6 is an example structural schematic diagram of an electronic device according to some embodiments of the present application. DETAILED DESCRIPTION

[0042] In order to make the objects, technical solutions and advantages of the present application clearer, the embodiments of the present application are described in detail below. It should be explained that the embodiments in the present application and the features in the embodiments can be combined with each other in any manner without conflict.

[0043] In order to make the technical solutions of the embodiments of the present application clearer, the drawings needed to be used in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some examples or embodiments of the present application, and for those skilled in the art, the present application can be applied to other similar scenarios without creative labor on the basis of the drawings. Unless it is obvious from the language environment or otherwise stated, the same reference signs in the drawings represent the same structure or operation.

[0044] It should be understood that the "system", "device", "unit" and / or "module" used herein is 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 the present application and claims, unless the context clearly indicates otherwise, "one", "a", "an" and / or "the" do not refer to the singular, but can also include the plural. Generally speaking, the terms "comprise" and "include" only indicate the inclusion of the steps and elements explicitly identified, and these steps and elements do not constitute an exclusive list, and the method or device can 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 subsequent operations are not necessarily performed in sequence. On the contrary, each step can be processed in reverse order or simultaneously. At the same time, other operations can be added to these processes, or one or more steps of the operation can be removed from these processes.

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

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

[0049] In some embodiments, the service end 110 and the terminal 120 can interact data or information through the network 130. For example, the service end 110 can obtain information and / or data in the terminal 120 through the network 130, or can send information and / or data to the terminal 120 through the network 130.

[0050] The terminal 120 is an electronic device for a user to determine the flow value of the first produced fluid in the first gathering pipeline, the flow value of water in the water mixing pipeline, and the flow value of the second produced fluid in the second gathering pipeline. In some embodiments, the terminal 120 can obtain a plurality of groups of first to-be-fitted data, and fit the oil-water content uplink curve of the oilfield produced fluid according to the plurality of groups of first to-be-fitted data. In some embodiments, the terminal 120 can obtain a plurality of groups of second to-be-fitted data, and fit the water-oil content downlink curve of the oilfield produced fluid according to the plurality of groups of second to-be-fitted data. In some embodiments, the terminal 120 can take the water cut corresponding to the intersection of the oil-water content uplink curve and the water-oil content downlink curve as the critical water cut, and determine the flow value of the first produced fluid in the first gathering pipeline, the flow value of water in the water mixing pipeline, and the flow value of the second produced fluid in the second gathering pipeline according to the critical water cut and the oil-water transition water cut. In the case that the computing resources of the terminal 120 are limited, the terminal 120 can send the plurality of groups of first to-be-fitted data and the plurality of groups of second to-be-fitted data to the service end 110, and the service end 110 determines the flow value of the first produced fluid in the first gathering pipeline, the flow value of water in the water mixing pipeline, and the flow value of the oilfield produced fluid in the second gathering pipeline according to the plurality of groups of first to-be-fitted data and the plurality of groups of second to-be-fitted data, and returns the flow value of the oilfield produced fluid in the first gathering pipeline, the flow value of water in the water mixing pipeline, and the flow value of the oilfield produced fluid in the second gathering pipeline to the terminal 120, so that the terminal 120 displays the flow value of the first produced fluid in the first gathering pipeline, the flow value of water in the water mixing pipeline, and the flow value of the second produced fluid in the second gathering pipeline to the user. The terminal 120 can be one or any combination of a mobile device, a tablet computer, and the like, which has input and / or output functions.

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

[0052] In some embodiments, the network 130 can be any one or more of a wired network or a wireless network. For example, the network 130 can 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 the convenience of understanding, the technical solutions of the present application are described below in conjunction with the drawings and embodiments.

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

[0055] As shown in Figure 2A , the viscosity reduction system for oilfield produced fluid provided by the embodiments of the present application includes a first oil collection pipe, a water mixing pipeline, and a second oil collection pipe. The water mixing pipeline is in communication with the first oil collection pipe at a first connection point, one end of the second oil collection pipe is in communication with the first oil collection pipe between the oil well and the first connection point at a second connection point, the other end of the second oil collection pipe is in communication with the first oil collection 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 that the side of the first oil collection pipe away from the oil well, i.e., the downstream of the first oil collection pipe).

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

[0057] The first connection point is configured to mix the first produced fluid and the water in the water mixing pipeline uniformly, and the liquid after mixing at the first connection point is referred to as the first mixed liquid;

[0058] The third connection point is configured to mix the first mixed liquid and the second produced fluid uniformly, and the liquid after mixing at the third connection point is referred to as the second mixed liquid.

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

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

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

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

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

[0064] Figure 3 is an exemplary flow chart of the viscosity reduction method of oilfield produced liquid according to some embodiments of the present application. The viscosity reduction method of oilfield produced liquid is applied to a viscosity reduction system of oilfield produced liquid as shown in Figure 2A as shown in Figure 3 The viscosity reduction method of oilfield produced liquid comprises the following steps.

[0065] In step S310, a plurality of groups of first fitting data are obtained, and the oil-water transition water cut of the oilfield produced liquid and the water-in-oil water cut uprun curve of the oilfield produced liquid are obtained according to the plurality of groups of first fitting data.

[0066] The oil-water transition water cut of the oilfield produced liquid and the water-in-oil water cut uprun curve of the oilfield produced liquid can also be directly obtained by measurement.

[0067] The fitting method can be:

[0068] The first fitting data includes different water cuts and corresponding viscosity values of the oilfield produced liquid in the water-in-oil state.

[0069] The oilfield produced liquid belonging to the oil-water mixture includes two states: the water-in-oil state (in the case of low water cut) and the oil-in-water state (in the case of high water cut).

[0070] In some embodiments, the plurality of groups of first fitting data can be obtained by the following method: after gradually adding water with a preset water amount to the first test crude oil, measuring the mixed liquid to obtain each group of first fitting data. The first test crude oil is crude oil with a water cut lower than a first preset threshold value and in the water-in-oil 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, crude oil with less water cut 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 cut of the oilfield produced liquid, for example, if the water cut of the oilfield produced liquid is 55%, the first preset threshold value can be 60%. In the specific implementation process, the water cut of the mixed liquid can be obtained by using various methods, such as distillation method, electric separation method, etc. The viscosity of the crude oil can be a measure of the frictional resistance of one part of the crude oil relative to the flow of another part, and the unit of viscosity is mPa·s. In the specific implementation process, the viscosity value of the crude oil can be measured by using various methods, such as dynamic viscosity measurement, kinematic viscosity measurement, and conditional viscosity measurement.

[0071] In the implementation process, the first test crude oil can be sequentially mixed with water in a preset water mixing amount, so that the water content of the mixed solution after each water mixing increases by 2-5 percentage points compared with that before water mixing. After each water mixing, the first test crude oil and water are uniformly stirred, and then the mixed solution is tested to obtain the water content and viscosity value of the mixed solution as a set of first fitting data.

[0072] In some embodiments, the preset water mixing amount can be obtained by: calculating a first product between a first volume and a first water content difference value; wherein the first volume is the volume of the mixed solution before the i-th water mixing of the first test crude oil, the first water content difference value is the difference between the water content of the mixed solution after the i-th water mixing of the first test crude oil and the water content of the mixed solution after the (i-1)-th water mixing of the first test crude oil, and i is an integer greater than 0; calculating the difference between 1 and the water content of the mixed solution after the i-th water mixing of the first test crude oil as a first difference value; and calculating the ratio between the first product and the first difference value to obtain the preset water mixing amount when the i-th water mixing is performed on the first test crude oil. The calculation formula is as follows:

[0073]

[0074] In formula (1), m i is the preset water mixing amount for the i-th water mixing of the first test crude oil; V i-1 is the first volume, i.e. the volume of the mixed solution before the i-th water mixing of the first test crude oil; and are the water content of the mixed solution after the i-th water mixing of the first test crude oil and the water content of the mixed solution after the (i-1)-th water mixing of the first test crude oil, respectively, can be obtained by summation operation between and the first water content difference value Δφ i The first water content difference value Δφ i can be set by the tester, and Δφ i ∈ [2%, 5%]. In the implementation process, the total number of water mixing of the first test crude oil can be denoted as I, which can be between 29 and 49, and after the last water mixing, can be between 85% and 95%.

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

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

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

[0078] In some embodiments, the water cut of the oilfield produced fluid can be taken as an independent variable, and the viscosity value of the oilfield produced fluid can be taken as a dependent variable to construct a monomial equation, which is as follows:

[0079]

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

[0081] In some embodiments, the fitting parameters of the monomial equation can be determined by solving the monomial equation according to the plurality of groups of first to-be-fitted data. For example, the water cut and the viscosity value data of the plurality of groups of first to-be-fitted data when Φ≤φ * can be substituted into formula (2), and the least square method can be used to solve formula (2) to determine the numerical values of the fitting parameters (a, b, and c).

[0082] In some embodiments, the water-in-oil water cut uplink curve can be drawn in a plane rectangular coordinate system according to the monomial equation with the determined fitting parameters. For example, a plurality of groups of coordinates (including x coordinates and y coordinates) can be obtained according to formula (2), a plurality of scattered points corresponding to the plurality of groups of coordinates can be drawn on the plane rectangular coordinate system, and then a curve can be used to connect the plurality of scattered points to obtain the water-in-oil water cut uplink curve a as shown in Figure 4 .

[0083] In the specific implementation process, after the water cut of the mixture of the first tested crude oil and water is greater than the water cut of the oil-water transition, the mixture is in the water-in-oil state, and water continues to be mixed into the mixture, a plurality of groups of water cut and viscosity value data of the oilfield produced fluid under the water-in-oil state can be obtained. In some embodiments, the following monomial equation can be constructed according to the physical properties of the oilfield produced fluid under the water-in-oil state:

[0084]

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

[0086] In some embodiments, the fitting parameters of the one-order multiple equation can be determined by solving (for example, using least square method) the one-order multiple equation using multiple sets of water cut and viscosity value data of oilfield produced liquid in oil-in-water state.

[0087] In some embodiments, the oil-in-water water cut uprun curve can be plotted in the plane rectangular coordinate system according to the one-order multiple equation with the determined fitting parameters. For example, multiple sets of coordinates (including x coordinate and y coordinate) can be obtained according to formula (3), multiple scattered points corresponding to the multiple sets of coordinates can be plotted on the plane rectangular coordinate system, and then the multiple scattered points can be connected by a curve to obtain the oil-in-water water cut uprun curve b as shown in Figure 4 .

[0088] Step S320, obtaining multiple sets of second fitting data, and fitting to obtain the oil-in-water water cut downrun curve of oilfield produced liquid according to the multiple sets of second fitting data.

[0089] The oil-in-water water cut downrun curve of oilfield produced liquid can also be directly obtained by measurement.

[0090] The second fitting data includes different water cut and corresponding viscosity value when oilfield produced liquid is in oil-in-water state. In some embodiments, the multiple sets of second fitting data can be obtained by the following method: after the second test crude oil is gradually mixed with a preset amount of anhydrous crude oil, the mixed liquid is measured to obtain each set of second fitting data. The second test crude oil is crude oil with water cut higher than the second preset threshold value (which can be a value greater than the oil-water transition water cut) and in oil-in-water state. In the specific implementation process, after the water mixing test on the first test crude oil is completed in step S210, the mixed liquid of the first test crude oil in oil-in-water state and water is used as the second test crude oil, and a preset amount of anhydrous crude oil is gradually mixed to reduce the water cut of the mixed liquid of the second test crude oil and anhydrous crude oil by 2% to 5% after the anhydrous crude oil is mixed. After the anhydrous crude oil is mixed each time, the second test crude oil and the anhydrous crude oil are stirred uniformly, and the water cut and viscosity value of the mixed liquid are tested to obtain a set of second fitting data.

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

[0092] a second product between a second volume and a second water cut difference value is calculated; wherein the second volume is a volume of the mixed fluid before the jth time of adding the water-free crude oil to the second test crude oil, the second water cut difference value is a difference value between a water cut of the mixed fluid after the j-1th time of adding the water-free crude oil and a water cut of the mixed fluid after the jth time of adding the water-free crude oil, and j is an integer greater than 0; a ratio between the second product and the water cut of the mixed fluid after the jth time of adding the water-free crude oil is calculated to obtain the preset oil mixing amount when the jth time of adding the water-free crude oil to the second test crude oil, and the calculation formula is as follows:

[0093]

[0094] In formula (4), n j is the preset oil mixing amount when the jth time of adding the water-free crude oil to the second test crude oil; W j-1 is the second volume, that is, the volume of the mixed fluid before the jth time of adding the water-free crude oil to the second test crude oil; λ j and λ j-1 are respectively the water cut of the mixed fluid after the jth time of adding the water-free crude oil and the water cut of the mixed fluid after the j-1th time of adding the water-free crude oil, and λ j can be obtained by subtraction operation between λ j-1 and the second water cut difference value Δφ i . The second water cut difference value Δλ j can be set by the tester, Δλ j ∈ [2%, 5%], and λ0 is equal to φi when i is equal to I (the total number of times of adding water to the test crude oil) in formula (1).

[0095] The above method obtains the preset oil mixing amount when the jth time of adding the water-free crude oil to the test crude oil by the volume ratio, and in some embodiments, the preset oil mixing amount when the jth time of adding the water-free crude oil to the second test crude oil can also be obtained by other methods (for example, by the weight ratio), which is not limited by the description in the specification.

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

[0097] In some embodiments, the water cut of the oilfield produced fluid can be taken as the independent variable, and the viscosity value of the oilfield produced fluid can be taken as the dependent variable to construct a one-variable multiple equation, and the one-variable multiple equation is as follows:

[0098]

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

[0100] In some embodiments, the above one-order multiple equation can be solved according to a plurality of sets of second to-be-fitted data to determine the fitting parameters of the one-order multiple equation. For example, the water content rate and viscosity value data in the plurality of sets of second to-be-fitted data can be substituted into formula (5), and the least square method can be used to solve formula (5) to determine the numerical values of the fitting parameters (p, q, r, and s).

[0101] In some embodiments, the water-in-oil water content downward curve can be drawn in the plane rectangular coordinate system according to the one-order multiple equation with the determined fitting parameters. For example, a plurality of sets of coordinates (including x coordinates and y coordinates) can be obtained according to formula (5), a plurality of scattered points corresponding to the plurality of sets of coordinates can be drawn on the plane rectangular coordinate system, and then a curve can be used to connect the plurality of scattered points to obtain the water-in-oil water content downward curve c as shown in Figure 4

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

[0103] As shown in Figure 4 When the water content rate of the oilfield produced liquid is between the water content rate corresponding to the intersection of the water-in-oil water content upward curve a and the water-in-oil water content downward curve c and the oil-water transition water content rate, the water-in-oil water content downward curve c is relatively gentle, that is, the water content rate of the oilfield produced liquid is significantly reduced in this interval, and the viscosity value of the oilfield produced liquid changes little, so the water content rate corresponding to the intersection of the water-in-oil water content upward curve and the water-in-oil water content downward curve can be taken as the critical water content rate. For example, as shown in Figure 4 the water content rate of the point D in the water-in-oil water content downward curve c is 71%, and its viscosity value is the same as that of the point B (water content rate 81%), which is 140 mPa·s.

[0104] Step S340, determining the flow value of the first produced liquid in the first oil collecting pipe, the flow value of water in the water mixing pipeline, and the flow value of the second produced liquid in the second oil collecting pipe according to the critical water content rate and the oil-water transition water content rate to meet the set conditions, the set conditions including that the water content rate of the first mixed liquid is higher than the oil-water transition water content rate, the water content rate of the second mixed liquid is higher than the critical water content rate and lower than the oil-water transition water content rate.

[0105] ​In some embodiments, the flow rate value of the first produced fluid in the first gathering pipe, the flow rate value of water in the water mixing pipeline, and the flow rate value of the second produced fluid in the second gathering pipe can be determined 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 condition and the target viscosity value to be reached. The relationship between the flow rate value of the first produced fluid and the flow rate value of the second produced fluid can be expressed by a formula:

[0106] x1+x2=Z (6)

[0107] In formula (6), x1 is a variable corresponding to the flow rate value of the first produced fluid, x2 is a variable corresponding to the flow rate value of the second produced fluid, and Z is the production value of the oil well collecting the oilfield produced fluid. x1 and x2 can have multiple value schemes.

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

[0109]

[0110] In formula (7), x1 is a variable corresponding to the flow rate value of the first produced fluid, x2 is a variable corresponding to the flow rate value of the second produced fluid, and x3 is a variable corresponding to the flow rate value of water in the water mixing pipeline, is the critical water cut, is the oil-water transition water cut, and a is the water cut of the oilfield produced fluid. x1, x2 and x3 can have multiple value schemes.

[0111] In the specific implementation process, according to formulas (6) and (7), a plurality of numerical combinations of the flow rate value of the first produced fluid, the flow rate value of the second produced fluid and the flow rate value of water in the water mixing pipeline can be obtained. According to the target viscosity value to be reached, one of the plurality of numerical combinations can be selected as the actual flow rate value of the first produced fluid, the flow rate value of the second produced fluid and the flow rate value of water in the water mixing pipeline. For example, the flow rate value of the first produced fluid, the flow rate value of the second produced fluid and the flow rate value of water in the water mixing pipeline in the plurality of numerical combinations can be used respectively to calculate a plurality of water cuts of the second mixed fluid in the first gathering pipe according to formula (7), and then the water cut (for example, 71%) corresponding to the target viscosity value (for example, 140 mPa·s) to be reached can be determined from the plurality of water cuts by referring to the oil-in-water water cut downward curve c shown in FIG. 6. Therefore, the flow rate value of the first produced fluid, the flow rate value of the second produced fluid and the flow rate value of water in the water mixing pipeline in the numerical combination corresponding to the calculated water cut are taken as the actual flow rate value of the first produced fluid, the flow rate value of the second produced fluid and the flow rate value of water in the water mixing pipeline. Figure 4

[0112] For example only, the production of an oil well is 40 m 3 ​ / d (cubic meters / day), the water content of the produced fluid currently being extracted from this oil well is 55%, forming a water-in-oil emulsion with a viscosity of 610 mPa·s. Figure 4 Point A is shown in the diagram. To meet the requirements of subsequent gathering and transportation, the viscosity of the produced fluid after water mixing needs to be reduced to 140 mPa·s.

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

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

[0115]

[0116]

[0117] When conducting upward viscosity tests with water content, as shown in Table 1, the maximum viscosity value is 1292 mPa·s when the water content is 74%, i.e., the water content Φ during oil-water transition. * It is 74%.

[0118] Based on the data in Table 1, the following can be obtained through fitting:

[0119] Water-in-oil water upflow curve:

[0120]

[0121] Water-in-oil water content upward curve:

[0122]

[0123] Water-in-oil water cut curve:

[0124]

[0125] Solving equations (8) and (10) simultaneously yields the critical moisture content. It is 51%.

[0126] As an example only, the production of a certain oil well is 40m³. 3 / d (cubic meters / day), the water content of the produced fluid currently being extracted from this oil well is 55%, forming a water-in-oil emulsion with a viscosity of 610 mPa·s. Figure 4 Point A is shown in the diagram.

[0127] Existing processes use a single mixing method, such as... Figure 2B As shown, each oil well is equipped with one oil gathering pipeline and one water injection pipeline. The oil gathering pipeline is used to transport produced fluids from the oil field, and the water injection pipeline is used to inject a large amount of water into the oil gathering pipeline. The flow rate of water injected into the oil gathering pipeline through the water injection pipeline is 54.7 m³ / s. 3The water content per day increased the water cut of the produced fluid in the oil gathering pipeline to 81%, higher than the 74% water cut required for oil-water transition. This transformed the produced fluid in the oil gathering pipeline into an oil-in-water emulsion, reducing its viscosity to 140 mPa·s. Figure 4 Point B is shown in the diagram. Each oil well is equipped with one oil gathering pipeline and one water mixing pipeline. The oil gathering pipeline is used to transport the produced fluid from the oil field in the oil well, and the water mixing pipeline is used to inject a large amount of water into the oil gathering pipeline. Let equation (9) equal 140 mPa·s, and the solution is obtained that the water cut after one mixing is 81%, as shown in the diagram. Figure 4 Point B is shown in the diagram. The current production fluid output from the oil well is 40 m³. 3 If the water content is 55% per day, then the amount of water added using a single-stage mixing method is 40 × (81% - 55%) ÷ (1 - 81%) = 54.7 m³. 3 / d.

[0128] The embodiments provided in this application are applied to, for example... Figure 2A The viscosity reduction system for produced fluids in the oilfield shown has two oil gathering pipes per well: a first oil gathering pipe and a second oil gathering pipe, and a water mixing pipe, employing a two-stage mixing method, such as... Figure 2A As shown.

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

[0130] Using formulas (6) and (7), the flow rate of the first produced fluid, the flow rate of the second produced fluid, and the flow rate of water in the mixing pipeline can be determined as follows: 11m 3 / d、29m 3 / d、22.1m 3 / d.

[0131] Let equation (10) equal 140 mPa·s, and we can solve it to find that the water content of the second mixture is 71%, 51% ≤ 71% ≤ 74%, which satisfies the requirements of equation (7).

[0132] The current production of oilfield fluid from the well is 40m³. 3 / d, with a moisture content of 55%, the calculated flow rate of water in the mixing pipe is: 40 × (71% - 55%) ÷ (1 - 71%) = 22.1 m 3 / d;

[0133] Assuming the water content of the first mixed solution is 85%, the flow rate of the first produced solution is: 22.1 × (1 - 85%) ÷ (85% - 55%) = 11 m³ 3 / d, the flow rate of the second produced fluid is: 40-11=29m³ 3 / d.

[0134] The flow rate of the first produced fluid in the first oil gathering pipe is set to 11 m³ / s. 3 / d, the flow rate of water in the mixing pipeline is set to 22.1m³ / d. 3 / d (third flow value), such as Figure 2A As shown, water in the water mixing pipe is injected into the first oil collection pipe at the first connection point, resulting in a flow rate of 33.1 m³ / s. 3 The first mixture in the first oil collection pipe of / d has a water content of 85%, which is higher than the 74% water content of the oil-water transition, and is an oil-in-water emulsion. Figure 4 As shown at point C in the diagram. Compared to the first produced fluid, the viscosity of the first mixed fluid is significantly reduced, resulting in a substantial decrease in frictional resistance between it and the oil gathering pipeline.

[0135] The flow rate of the second produced fluid in the second oil gathering pipe is set to 29m. 3 / d, such as Figure 2A As shown, the second produced fluid in the second oil gathering pipe is injected into the first oil gathering pipe at the third connection point, resulting in a flow rate of 62.1 m³ / s. 3 The second mixture in the first oil collection pipe / d is still an oil-in-water emulsion with a viscosity of 140 mPa·s.

[0136] The second mixture is obtained by treating the first produced fluid in the first oil gathering pipe, the water in the water mixing pipe, and the second produced fluid in the second oil gathering pipe using the secondary mixing method provided in this application embodiment. The viscosity values ​​of the first produced fluid in the first oil gathering pipe and the second produced fluid in the second oil gathering pipe are both 610 mPa·s, while the viscosity value of the second mixture in the first oil gathering pipe is reduced to 140 mPa·s (the same as the viscosity value after treating the oilfield produced fluid in the oil gathering pipe using existing processes). The water mixing amount is reduced from 54.7 m³ / s required by existing processes. 3 / d decreased to 22.1m 3 / d, the reduction rate reached 59.7%; and the flow rate of the second mixture in the first oil collection pipe increased from 94.7m 3 / d decreased to 62.1m 3 / d, the reduction rate reaches 34.5%. If the first oil gathering pipe is in laminar flow, compared with the mixture in the oil gathering pipe obtained by the existing single-mixing method, the frictional resistance between the second mixture in the first oil gathering pipe and the pipe can be reduced by 34.5%. If the first oil gathering pipe is in the hydraulically smooth region, compared with the mixture in the oil gathering pipe obtained by the existing single-mixing method, the frictional resistance between the second mixture in the first oil gathering pipe and the pipe can be reduced by 52.2%.

[0137] In summary, the embodiments provided in this application obtain a second mixture with lower viscosity and lower water content in the first oil gathering pipe through a two-stage mixing method, thereby reducing the viscosity of the oilfield produced fluid in the oil gathering pipe and lowering the transportation cost of the oilfield produced fluid.

[0138] Step S350: Based on the flow rate of the first produced fluid in the first oil gathering pipe, the flow rate of water in the water mixing pipe, and the flow rate of the second produced fluid in the second oil gathering pipe, the oilfield produced fluid is subjected to viscosity reduction treatment through the oilfield produced fluid viscosity reduction system.

[0139] In the specific implementation process, based on the flow rate values ​​of the first produced fluid in the first oil gathering pipe, the water flow rate in the water mixing pipe, and the second produced fluid in the second oil gathering pipe obtained in step S340, the following settings can be made respectively: Figure 2A The values ​​of flow rates for the first oil gathering pipe, the water mixing pipe, and the second oil gathering pipe in the viscosity reduction system of the oilfield produced fluid are shown.

[0140] Figure 5 This is an exemplary schematic diagram of a viscosity-reducing device for oilfield produced fluids according to some embodiments of this 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 cut acquisition module 530, a flow rate determination module 540, and a viscosity reduction module 550.

[0142] The first fitting module 510 is used to acquire multiple sets of first data to be fitted, obtain the water cut of oil-water transition based on the multiple sets of first data to be fitted, and fit the upward curve of the water cut in oil-in-water of the oilfield produced fluid; wherein, the first data to be fitted includes different water cuts and their corresponding viscosity values ​​when the oilfield produced fluid is in the water-in-oil state, and the water cut of oil-water transition is the water cut corresponding to the maximum viscosity value among the multiple sets of first data to be fitted.

[0143] The second fitting module 520 is used to acquire multiple sets of second data to be fitted, and to fit the water-in-oil water content downward curve of the oilfield produced fluid based on the multiple sets of second data to be fitted; wherein, the second data to be fitted includes different water contents and their corresponding viscosity values ​​when the oilfield produced fluid is in the water-in-oil state.

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

[0145] The flow value determination module 540 is configured to determine flow values of the first produced fluid in the first gathering pipe, water in the water mixing pipeline and the second produced fluid in the second gathering pipe according to the critical water cut and the oil-water transition water cut, so as to meet the set condition, and the set condition includes that the water cut of the first mixed fluid is higher than the oil-water transition water cut, and the water cut of the second mixed fluid is higher than the critical water cut and lower than the oil-water transition water cut.

[0146] The flow values can be combined with the above-mentioned flow values, and the temperature of the first gathering pipe is set to not affect the water cut of the first mixed fluid to be higher than the oil-water transition water cut, and the temperature of the second gathering pipe is set to not affect the water cut of the second mixed fluid to be higher than the critical water cut and lower than the oil-water transition water cut.

[0147] The viscosity reduction module 550 is configured to perform viscosity reduction processing on the oilfield produced fluid by the viscosity reduction system of the oilfield produced fluid according to the flow values of the first produced fluid in the first gathering pipe, water in the water mixing pipeline and the second produced fluid in the second gathering pipe.

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

[0149] Figure 6 FIG. 1 is a schematic structural diagram of an electronic device according to some embodiments of the present application.

[0150] As shown in FIG. 1, 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. Figure 6 The processor 601 can be a processor CPU, or a specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement embodiments of the present application. The memory 603 can include a high-speed RAM memory, and can also include a non-volatile memory such as at least one disk memory. The memory 603 stores a program, and the processor 601 invokes the program stored in the memory 603 to execute part or all of the above-mentioned method embodiments.

[0151] Having described the basic concepts, it is obvious that the above detailed disclosure is intended to be illustrative only and not restrictive of the present application. Various modifications, improvements, and changes can be made to the present application by those skilled in the art. Such modifications, improvements, and changes are suggested to be within the spirit and scope of the present application, and the examples of the present application are intended to be illustrative only and not restrictive of the present application.

[0152] Also, the present application uses specific terminology in describing the embodiments of the present application. The use of "one embodiment," "an embodiment," and / or "some embodiments" of the present application herein means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Therefore, it is emphasized and should be appreciated that a referenced "embodiment" or "one embodiment" or "an alternative embodiment" of the present application described herein is not necessarily to be construed as applying only to that single embodiment but also to the various embodiments, and that a variety of

[0153] Also, unless explicitly stated otherwise, the order of process elements, the use of the articles "a" and "an," or other ordinal language, are not intended to imply a particular order to the steps in the process and method disclosed herein. Although the above disclosure discusses some presently preferred embodiments of the application, it is to be understood that the details disclosed herein are merely examples of embodiments of the application and that additional modifications and equivalents of the methods and apparatus described herein can be used to practice the application. For example, although the system components described above can be implemented in hardware devices, they can also be implemented in software solutions, such as installing the described system on an existing server or mobile device.

[0154] Similarly, it is to be noticed that the term "comprising", used in the description, is not to be interpreted as being restricted to the means listed thereafter. It is to be understood that other embodiments can be utilized and structural or logical changes can be made without departing from the scope of the present application. Furthermore, structures and functionality presented as separate components in example configurations can be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component can be implemented as separate components. These and other changes can be made to the application in light of the above-detailed description. The detailed description is to be understood as including all technical equivalents of the structures described herein.

[0155] In some embodiments, numbers that describe amounts, dimensions, and so forth, are used in the description of the embodiments. It should be understood that such numbers are used only to illustrate certain embodiments and that the application is not limited to the numbers. In some examples, such numbers are modified by the modifier "about" or "approximately." Unless otherwise specified, "about" or "approximately" means ±20% of the value of the measured quantity that the term describes. Accordingly, in some embodiments, the numerical parameters in the description and claims are approximations that can vary depending upon the desired properties sought to be obtained by the individual embodiments. In some embodiments, numerical parameters are determined by the use of standard techniques. Although the numerical ranges and parameters setting forth the broad scope of the application are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values set forth in the specific examples are provided to be as precise as reasonably possible. However, some variations may occur depending on the choice of input used to develop or derive the numerical values in the examples.

[0156] Each patent, patent application, publication, and other material cited in this application is hereby incorporated by reference in its entirety. In the event of inconsistencies between the disclosure of this application and the materials incorporated by reference, the disclosure of this application is controlling. In the event of inconsistencies between the disclosure of this application and the disclosure of the incorporated application history documents, the disclosure of this application is controlling. It is specifically noted that, if there is a discrepancy between the terminology used in the disclosure of this application and the terminology used in the incorporated materials, the terminology associated with this application is to be controlled.

[0157] Finally, it should be understood that the embodiments described herein are merely exemplary of the application. Other variations of the embodiments can be devised by those skilled in the art without departing from the scope of the present application. Accordingly, the embodiments described herein are intended to be illustrative only and are not limiting of the scope of the present application.

Claims

1. A method of reducing the viscosity of oilfield produced fluids, characterized in that, A viscosity reduction system for oilfield produced fluid, the viscosity reduction system comprising: a first gathering pipeline, a water blending pipeline, and a second gathering pipeline; the water blending pipeline is in communication with the first gathering pipeline at a first connection point, one end of the second gathering pipeline is in communication with the first gathering pipeline at a second connection point between the oil well and the first connection point, the other end of the second gathering pipeline is in communication with the first gathering pipeline at a third connection point, the third connection point is in the direction away from the oil well from the first connection point; the second connection point is configured to split the oilfield produced fluid to the first gathering pipeline and the second gathering pipeline; the oilfield produced fluid in the first gathering pipeline is referred to as first produced fluid, the oilfield produced fluid in the second gathering pipeline is referred to as second produced fluid; the first connection point is configured to mix the first produced fluid and water in the water blending pipeline uniformly; the mixed fluid at the first connection point is referred to as first mixed fluid; the third connection point is configured to mix the first mixed fluid and the second produced fluid uniformly, the mixed fluid at the third connection point is referred to as second mixed fluid; the viscosity reduction method comprising: measuring or fitting the oil-water transition water cut of the oilfield produced fluid; measuring or fitting the first viscosity value and the corresponding first water cut when the water cut of the oilfield produced fluid gradually increases under the water-in-oil condition, and measuring or fitting the second viscosity value and the second water cut when the water cut of the oilfield produced fluid gradually decreases under the oil-in-water condition, taking the water cut when the first water cut and the second water cut are equal and the first viscosity value and the second viscosity value are equal as the critical water cut; determining the flow rate value of the first produced fluid in the first gathering pipeline, the flow rate value of water in the water blending pipeline, and the flow rate value of the second produced fluid in the second gathering pipeline according to the critical water cut and the oil-water transition water cut to meet the set conditions, the set conditions including that the water cut of the first mixed fluid is higher than the oil-water transition water cut, and the water cut of the second mixed fluid is higher than the critical water cut and lower than the oil-water transition water cut; performing viscosity reduction treatment on the oilfield produced fluid through the viscosity reduction system of the oilfield produced fluid according to the flow rate value of the first produced fluid in the first gathering pipeline, the flow rate value of water in the water blending pipeline, and the flow rate value of the second produced fluid in the second gathering pipeline.

2. The viscosity reduction method of claim 1, wherein The determination of the flow rate value of the first produced fluid in the first gathering pipeline, the flow rate value of water in the water blending pipeline, and the flow rate value of the second produced fluid in the second gathering pipeline according to the critical water cut and the oil-water transition water cut comprises: determining the flow rate value of the first produced fluid in the first gathering pipeline, the flow rate value of water in the water blending pipeline, and the flow rate value of the second produced fluid in the second gathering pipeline 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 reached.

3. The viscosity reduction method of claim 1, wherein The viscosity of the oilfield produced fluid in the viscosity reduction method is 10 mPa.s to 2000 mPa.s; the water cut of the oilfield produced fluid is not more than 75 wt.%.

4. The viscosity reduction method according to any one of claims 1 to 3, characterized by, The temperature of the first oil collecting pipe is set to not affect the water content of the first mixed liquid to be higher than the oil-water transition water content, and the temperature of the second oil collecting pipe is set to not affect the water content of the second mixed liquid to be higher than the critical water content and lower than the oil-water transition water content.

5. The viscosity reduction method of any one of claims 1 to 3, wherein, The flow ratio of the first produced liquid to the second produced liquid is controlled to be 10: (11 to 100), and the flow ratio of the first produced liquid to water is controlled to be 10: (13 to 50).

6. The viscosity reduction method of any one of claims 1 to 3, wherein, The viscosity reduction method does not use a flow modifier.

7. The viscosity reduction method of claim 1, wherein The first connection point is configured to make the first mixed liquid flow along the first oil collecting pipe to the third connection point, and the third connection point is configured to make the second mixed liquid flow along the first oil collecting pipe away from the first connection point.

8. The viscosity reduction method of claim 1, wherein The material of the first oil collecting pipe is hydrophilic material.

9. The viscosity reduction method of claim 1, wherein The ratio of the pipe length between the first connection point and the second connection point to the pipe length between the first connection point and the third connection point is 1: (1 to 2).

10. The viscosity reduction method of claim 1, wherein The ratio of the pipe diameter of the first oil collecting pipe to the pipe diameter of the second oil collecting pipe is 1: (2 to 5).

11. A viscosity reduction device for oilfield produced fluids, comprising: The viscosity reduction device comprises: A first fitting module is configured to obtain a plurality of first fitting data, and obtain an oil-water transition water content and a water-in-oil water content up curve of the oilfield produced liquid by fitting the plurality of first fitting data. The first fitting data includes different water contents and corresponding viscosity values of the oilfield produced liquid in a water-in-oil state, and the oil-water transition water content is the water content corresponding to the maximum viscosity value in the plurality of first fitting data. A second fitting module is configured to obtain a plurality of second fitting data, and obtain a water-in-oil water content down curve of the oilfield produced liquid by fitting the plurality of second fitting data. The second fitting data includes different water contents and corresponding viscosity values of the oilfield produced liquid in a water-in-oil state. A critical water content obtaining module is configured to obtain the intersection point of the water-in-oil water content up curve and the water-in-oil water content down curve as the critical water content. A flow value determining module is configured to determine the flow value of the first produced liquid in the first oil collecting pipe, the flow value of water in the water mixing 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, so as 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 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. A viscosity reduction module is configured to perform viscosity reduction treatment on the oilfield produced liquid by a viscosity reduction system of the oilfield produced liquid 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 pipeline, and the flow value of the second produced liquid in the second oil collecting pipe. The water-mixing pipeline is communicated with the first oil collecting pipeline at a first connection point, one end of the second oil collecting pipeline is communicated with the first oil collecting pipeline at a second connection point between the oil well and the first connection point, and the other end of the second oil collecting pipeline is communicated with the first oil collecting pipeline at a third connection point which is located in a direction away from the oil well from the first connection point; The second connection point is configured to split the oilfield produced liquid to the first oil collecting pipeline and the second oil collecting pipeline; the oilfield produced liquid in the first oil collecting pipeline is recorded as first produced liquid, and the oilfield produced liquid in the second oil collecting pipeline is recorded as second produced liquid; The first connection point is configured to mix the first produced liquid and water in the water-mixing pipeline uniformly; the mixed liquid at the first connection point is recorded as first mixed liquid; The third connection point is configured to mix the first mixed liquid and the second produced liquid uniformly; the mixed liquid at the third connection point is recorded as second mixed liquid.

12. The viscosity reducing device of claim 11, wherein, The first connection point is configured to make the first mixed liquid flow along the first oil collecting pipeline to the third connection point; and the third connection point is configured to make the second mixed liquid flow along the first oil collecting pipeline in a direction away from the first connection point.

13. The viscosity reducing device of claim 11, wherein, The material of the first oil collecting pipeline is hydrophilic material.

14. The viscosity reducing device of claim 11, wherein, The ratio of the pipeline length between the first connection point and the second connection point to the pipeline length between the first connection point and the third connection point is 1:(1-2).

15. The viscosity reducing device of claim 11, wherein, The ratio of the pipe diameter of the first oil collecting pipeline to the pipe diameter of the second oil collecting pipeline is 1:(2-5). 16.An electronic device, comprising a memory and a processor, the memory stores a computer program, and the processor executes the computer program to perform the viscosity reduction method according to any one of claims 1-10. 17.A storage device for storing a computer readable program, the computer readable program, when executed, performs the viscosity reduction method according to any one of claims 1-10.

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