Thickened oil recovery assisting system and method with dilution and viscosity reduction functions

Abstract

The system comprises a light / mixed hydrocarbon pre-mixing unit, a light / mixed hydrocarbon pre-mixing unit, a light / mixed hydrocarbon pre-mixing unit, a light / mixed hydrocarbon pre-mixing unit and a mixed hydrocarbon pre-mixing unit, the light / mixed hydrocarbon pre-mixing unit is used for receiving light hydrocarbon and mixed hydrocarbon with a certain proportion from a crude oil extraction united station and pre-mixing the light hydrocarbon and the mixed hydrocarbon for later use; the thin oil dosing unit is used for receiving output thin crude oil and adding an asphaltene stabilizer for later use; and the diluted medium mixing unit is used for receiving the premixed light hydrocarbon, the premixed mixed hydrocarbon and the added diluted crude oil, mixing and heating to form a diluted medium, and the diluted medium is transferred to a well mouth through a crude oil exploitation metering station and is used for thickened oil diluted viscosity reduction exploitation. The light hydrocarbon and the mixed hydrocarbon produced by the oil field united station are mixed with the dilute crude oil added with the asphaltene stabilizer according to a certain proportion to form a dilute medium, so that the viscosity of the heavy oil can be effectively reduced, and the consumption of the dilute crude oil is lower.

Description

Technical Field

[0001] The invention relates to the technical field of heavy oil production, and in particular to a system and method for assisting heavy oil production by diluting and reducing viscosity using light hydrocarbons and mixed hydrocarbons produced on-site. Background Art

[0002] After years of development and utilization, the output of conventional crude oil has gradually decreased, and the output of unconventional oil reservoirs such as heavy oil has increased year by year. The development and utilization of heavy oil has also attracted more and more attention. A major problem in the heavy oil production process is the high viscosity of heavy oil. Due to the poor quality of heavy oil, crude oil contains a large amount of colloid asphaltene, which leads to extremely high viscosity and poor fluidity of crude oil, making it difficult to produce from the bottom of the well. Therefore, excessively high crude oil viscosity is the main problem restricting heavy oil production.

[0003] At present, the main methods for reducing the viscosity of heavy oil include chemical viscosity reduction and physical viscosity reduction. Chemical viscosity reduction is a method of reducing the viscosity of heavy oil by changing the molecular structure of heavy oil by adding external chemical agents. Due to the high cost of agents and the certain pollution of chemical agents, the subsequent treatment and utilization of crude oil have caused additional difficulties. In contrast, physical viscosity reduction has less impact on the environment and the properties of crude oil itself.

[0004] There are many existing physical viscosity reduction methods, including ultrasonic viscosity reduction, microwave viscosity reduction, heating viscosity reduction, and dilution viscosity reduction. Heating viscosity reduction and dilution viscosity reduction are widely used in major oil fields to reduce the viscosity of heavy oil. Among them, for conventional oil reservoirs or general heavy oil reservoirs, the viscosity of crude oil is not high, and appropriate heating can meet the process requirements. However, for super-heavy oil and extra-heavy oil reservoirs, if the temperature needs to be raised by dozens of degrees or even hundreds of degrees by heating to reduce viscosity, not only will the industrial energy consumption be large and the cost be high, but there will also be problems with construction and operation safety. Therefore, for super / extra-heavy oil with extremely high viscosity, an appropriate amount of thin oil medium will be added to the crude oil while heating to reduce viscosity, so as to achieve the effect of reducing the viscosity of the crude oil.

[0005] However, diluting and reducing viscosity requires a large amount of rare oil, and the external transmission of rare oil also requires an additional rare oil gathering and transportation system. The cost of relying solely on external rare oil blending and reducing viscosity is relatively high.

[0006] Therefore, there is an urgent need for a system and method for reducing the viscosity of heavy oil by diluting the heavy oil, which can effectively reduce the amount of rare crude oil used and ensure the reduction in crude oil viscosity.

[0007] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0008] The purpose of the present invention is to provide a system and method for assisting heavy oil production by using light hydrocarbons and mixed hydrocarbons produced on-site to dilute and reduce viscosity. The light hydrocarbons and mixed hydrocarbons produced by the oil field joint station are mixed with rare crude oil added with asphaltene stabilizer in a certain proportion to form a diluting medium, which can not only effectively reduce the viscosity of the heavy oil, but also use less rare crude oil.

[0009] Another object of the present invention is to dynamically monitor the viscosity changes of the outer pipe thin oil and produced oil and the precipitation of asphaltene, and adjust the dosage of light, mixed hydrocarbons and asphaltene stabilizer in real time, so as to achieve the best technical and economic effects.

[0010] To achieve the above-mentioned purpose, according to the first aspect of the present invention, there is provided a system for assisting heavy oil production by dilution and viscosity reduction, comprising: a light / mixed hydrocarbon premixing unit, which receives light hydrocarbons and mixed hydrocarbons with a certain proportion from a crude oil production joint station and premixes them for standby; a thin oil dosing unit, which receives external rare crude oil and adds asphaltene stabilizer for standby; a dilution medium mixing unit, which receives the premixed light hydrocarbons and mixed hydrocarbons and the rare crude oil after dosing, mixes and heats them to form a dilution medium, and the dilution medium is transported to the wellhead through a crude oil production transfer station for heavy oil dilution and viscosity reduction production.

[0011] Furthermore, in the above technical solution, the light / mixed hydrocarbon premixing unit may include: a light hydrocarbon tank, which is a liquid insulated storage tank and receives light hydrocarbons from the combined station; a mixed hydrocarbon tank, which is a liquid insulated storage tank and receives mixed hydrocarbons from the combined station; and a premixing tank, which receives the mixed light hydrocarbons and mixed hydrocarbons from the premixer and keeps them in reserve.

[0012] Furthermore, in the above technical solution, a first booster pump may be provided between the hydrocarbon mixing tank and the premixer to mix the boosted mixed hydrocarbon with the light hydrocarbon.

[0013] Furthermore, in the above technical solution, the thin oil dosing unit may include: a thin oil tank connected to an external thin crude oil pipeline; a stabilizer storage tank for storing asphaltene stabilizer; and a dosing tank for receiving the thin crude oil and asphaltene stabilizer mixed from the dosing mixer and keeping them in reserve.

[0014] Furthermore, in the above technical solution, a second booster pump may be provided on the outlet pipeline of the dosing tank.

[0015] Furthermore, in the above technical solution, the dilution medium mixing unit may include: a dilution mixer, which receives the pre-mixed light hydrocarbons and mixed hydrocarbons and the rare crude oil after the addition of drugs, and mixes them; a dilution tank, which receives the mixed liquid from the dilution mixer and stores it for standby use; a heater, which is arranged on the outlet pipeline of the dilution tank, and is used to heat the mixed liquid from the dilution tank and use it as a dilution medium.

[0016] Furthermore, in the above technical solution, the dilution viscosity reduction assisted heavy oil production system may also include a monitoring control unit, which may specifically include: a dynamic viscosity analyzer, which is arranged at the manifold of the meter transfer station and at the inlet of the dilution tank, and is used to monitor the viscosity data of the dilution medium and the wellhead produced fluid in real time; a solid particle detector, which is arranged at the manifold of the meter transfer station and at the inlet of the dilution tank, and is used to monitor the solid phase particle content data in real time; a ratio controller, which adjusts the addition amount of the asphaltene stabilizer, the ratio of light hydrocarbons / mixed hydrocarbons to rare crude oil, and the addition amount of the dilution medium in real time according to the viscosity data and the solid phase particle content data.

[0017] According to a second aspect of the present invention, the present invention provides a method for assisting heavy oil production by dilution and viscosity reduction, comprising the following steps: A. premixing light hydrocarbons and mixed hydrocarbons produced by a crude oil production joint station in a certain proportion for standby use; B. adding an asphaltene stabilizer to the exported rare crude oil for standby use; C. mixing and heating the premixed light hydrocarbons and mixed hydrocarbons and the rare crude oil after adding the drug to form a dilution medium, and transporting the dilution medium to the wellhead through a crude oil production meter station for heavy oil dilution and viscosity reduction production.

[0018] Furthermore, in the above technical solution, before the light hydrocarbons and the mixed hydrocarbons are premixed in step A, a processing step of increasing the pressure of the mixed hydrocarbons may be included.

[0019] Furthermore, in the above technical solution, in step B, after the asphaltene stabilizer is added to the imported rare crude oil for mixing and before use, a pressure-increasing treatment step may be included.

[0020] Furthermore, in the above technical solution, the dilution viscosity reduction assisted heavy oil production method may also include a monitoring and control step, which specifically includes: collecting viscosity data and solid particle content data of the dilution medium and the wellhead produced fluid at the manifold of the metering station and the inlet of the dilution tank; and adjusting the amount of asphaltene stabilizer added, the ratio of light hydrocarbons / mixed hydrocarbons to rare crude oil, and the amount of dilution medium added in real time according to the viscosity data and the solid particle content data.

[0021] Furthermore, in the above technical solution, the amount of asphaltene stabilizer added, the ratio of light hydrocarbons / mixed hydrocarbons to rare crude oil, and the amount of diluent added can be controlled by flow regulating valves at corresponding positions.

[0022] Furthermore, in the above technical solution, after monitoring and controlling the ratio, the dilution ratio of light / mixed hydrocarbons to exported rare crude oil can be 0.5:1; and the viscosity of the produced oil can be below 1000mPa.s.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) The present invention reduces the viscosity of the diluting medium by adding light hydrocarbons and mixed hydrocarbons to the rare crude oil, thereby achieving a better effect of reducing the viscosity of the heavy oil by diluting; by making full use of the light hydrocarbons and mixed hydrocarbons produced on site in the oil field, the amount of the exported rare crude oil can be effectively reduced, saving the production cost of heavy oil by diluting and reducing the viscosity;

[0025] 2) The present invention prevents the precipitation of crude oil asphaltene due to the change of crude oil components during the dilution of light hydrocarbons by adding a small amount of asphaltene stabilizer, making the dilution and viscosity reduction of heavy oil safer and more stable;

[0026] 3) The present invention dynamically monitors the liquid viscosity and solid particle content at the manifold of the meter transfer station and the inlet of the dilution tank to dynamically control the dilution ratio, that is, the amount of light / mixed hydrocarbons and stabilizer added can be dynamically adjusted according to the dilution medium, produced oil viscosity and solid particle content, thereby saving production costs as much as possible while ensuring the stability of the properties of the produced fluid;

[0027] 4) The process flow of the invention for assisting heavy oil recovery by diluting and reducing viscosity is simple and easy to operate.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a connection schematic diagram of the system for assisting heavy oil production by diluting and reducing viscosity according to the present invention.

[0030] Figure 2 It is a connection diagram of the monitoring and control unit in the dilution viscosity reduction auxiliary heavy oil production system of the present invention.

[0031] Description of main reference numerals:

[0032] 1-light / mixed hydrocarbon premixing unit, 11-light hydrocarbon tank, 12-mixed hydrocarbon tank, 13-first booster pump, 14-premixer, 15-premixing tank, 151-first flow regulating valve, 2-thin oil dosing unit, 21-thin oil tank, 22-stabilizer storage tank, 221-second flow regulating valve, 23-dosing mixer, 24-dosing tank, 25-second booster pump, 3-dilute medium mixing unit, 31-dilute mixer, 32-dilute tank, 321-third flow regulating valve, 33-heater, 4-monitoring control unit, 40-dynamic viscosity analyzer and solid particle detector. DETAILED DESCRIPTION

[0033] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0034] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0035] In this document, for the convenience of description, spatial relative terms such as "below", "below", "down", "above", "above", "upper", etc. may be used to describe the relationship between one element or feature and another element or feature in the accompanying drawings. It should be understood that the spatial relative terms are intended to include different orientations of the object in use or operation in addition to the orientation depicted in the figure. For example, if the object in the figure is turned over, the element described as being "below" or "below" other elements or features will be oriented "above" the element or feature. Therefore, the exemplary term "below" can include both below and above. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatial relative terms used in this document should be interpreted accordingly.

[0036] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit a specific position or relative relationship. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable.

[0037] like Figure 1 As shown, the present invention provides a system for assisting heavy oil production by dilution and viscosity reduction, comprising a light / mixed hydrocarbon premixing unit 1, a dilution oil dosing unit 2, and a dilution medium mixing unit 3. The light / mixed hydrocarbon premixing unit 1 receives light hydrocarbons and mixed hydrocarbons with a certain proportion from a crude oil production joint station and premixes them for standby; the dilution oil dosing unit 2 receives the external rare crude oil and adds an asphaltene stabilizer for standby; the dilution medium mixing unit 3 receives the premixed light hydrocarbons and mixed hydrocarbons and the rare crude oil after dosing, mixes and heats them to form a dilution medium, and the dilution medium is transported to the wellhead through the crude oil production meter transfer station for heavy oil dilution and viscosity reduction production. The system of the present invention can use the light hydrocarbons and mixed hydrocarbons produced on site in the oil field for the process of diluting and reducing the viscosity of heavy oil. In this process, the light hydrocarbons and mixed hydrocarbons produced by the oil field joint station are mixed with rare crude oil added with asphaltene stabilizer in a certain proportion. The formed diluting medium can more effectively reduce the viscosity of the heavy oil and improve the fluidity of the heavy oil, and the amount of rare crude oil used is lower. Part of the light hydrocarbons and mixed hydrocarbons can also be recycled and reused at the joint station, saving the cost of heavy oil extraction.

[0038] Further Figure 1As shown, the light / mixed hydrocarbon premixing unit specifically includes a light hydrocarbon tank 11, a mixed hydrocarbon tank 12 and a premixing tank 15. Among them, the light hydrocarbon tank 11 is a liquid insulation storage tank and receives light hydrocarbons from the joint station. Specifically, the light hydrocarbon tank 11 is a liquid storage tank with a certain volume. The input end of the light hydrocarbon tank 11 is connected to the light hydrocarbon pipeline outside the joint station through a pipeline. The light hydrocarbon tank 11 has a certain pressure resistance level and insulation level to ensure that the light hydrocarbons in the tank are always in a liquid state. The light hydrocarbon tank 11 is equipped with conventional storage tank facilities such as a liquid level monitoring device, a safety valve, and a reserved bottom water outlet. The output end of the light hydrocarbon tank 11 is connected to the premixer 14 through a pipeline. The mixed hydrocarbon tank 12 is a liquid insulation storage tank and receives mixed hydrocarbons from the joint station. Specifically, the mixed hydrocarbon tank 12 is also a pressure-resistant and heat-insulated liquid storage tank with a certain volume. The input end of the mixed hydrocarbon tank 12 is connected to the mixed hydrocarbon pipeline outside the joint station through a pipeline, and the output end of the mixed hydrocarbon tank 12 is connected to the first booster pump 13 through a pipeline. The first booster pump can be a conventional liquid booster pump, whose input end is connected to the mixed hydrocarbon tank 12, and whose output end is connected to the premixer 14. The first booster pump 13 can make the mixed hydrocarbon pressure flowing out of the mixed hydrocarbon tank reach a corresponding level, so as to facilitate mixing with light hydrocarbons. The premixer 15 receives the mixed light hydrocarbons and mixed hydrocarbons from the premixer 14 and keeps them in reserve. The premixer 14 can be a static mixer, whose input end is connected to the first booster pump 13 and the light hydrocarbon tank 11 through pipelines respectively. The mixed hydrocarbons delivered by the first booster pump 13 and the light hydrocarbons delivered by the light hydrocarbon tank 11 are mixed in a certain proportion in the premixer 14, and are discharged from the output end of the premixer 14 after complete mixing. The output end of the premixer 14 is connected to the premixer 15 through a pipeline. The premixer 15 is a conventional pressure-resistant heat-insulating storage tank, which is used to store the mixed hydrocarbons after the light hydrocarbons and mixed hydrocarbons are mixed. The input end of the premixer 15 is connected to the premixer 14 through a pipeline, and the output end enters the dilution medium mixing unit 3 through a pipeline.

[0039] Further Figure 1As shown, the thin oil dosing unit includes a thin oil tank 21, a stabilizer storage tank 22 and a dosing tank 24. Among them, the thin oil tank 21 is connected to the external rare crude oil pipeline. Specifically, the thin oil tank 21 can adopt a conventional pressure-resistant and heat-insulated crude oil storage tank, the input end of which is connected to the rare crude oil pipeline from the outside, and the output end is connected to the dosing mixer 23 through a pipeline. The stabilizer storage tank 22 is used to store asphaltene stabilizer. Specifically, the stabilizer storage tank can adopt a conventional pressure-resistant and heat-insulated liquid phase storage tank, the finished stabilizer is added to the stabilizer storage tank through the inlet of the stabilizer storage tank 22 for storage, and the outlet of the stabilizer storage tank 22 is connected to the dosing mixer 23 through a pipeline. The dosing tank 24 receives the rare crude oil and asphaltene stabilizer mixed from the dosing mixer 23 and keeps them in reserve. Specifically, the dosing mixer 23 can be a static mixer, whose input end is connected to the thin oil tank 21 and the stabilizer storage tank 22 through pipelines, respectively. The asphaltene stabilizer and the rare crude oil flow into the dosing mixer 23 in a certain proportion and mix, and the fully mixed liquid crude oil is discharged from the output end of the dosing mixer 23, and the output end of the dosing mixer 23 is connected to the dosing tank 24 through a pipeline. Preferably, but not restrictively, a second booster pump 25 is provided on the outlet pipeline of the dosing tank. The second booster pump 25 can also be a conventional liquid booster pump, whose input end is connected to the dosing tank 24. The second booster pump 25 can make the pressure of the rare crude oil flowing out of the dosing tank 24 reach a certain level, so as to facilitate mixing with the liquid flowing out of the light / mixed hydrocarbon premixing unit, and the output end of the second booster pump 25 enters the diluting medium mixing unit 3 through a pipeline.

[0040] Further Figure 1As shown, the dilution medium mixing unit includes a dilution mixer 31, a dilution tank 32 and a heater 33. The dilution mixer 31 receives the pre-mixed light hydrocarbons and mixed hydrocarbons and the rare crude oil after dosing, and mixes them. Specifically, the dilution mixer 31 can adopt a conventional static mixer, and its input end is connected to the light / mixed hydrocarbon pre-mixing unit 1 and the rare crude oil dosing unit 2 through pipelines, respectively. The mixed hydrocarbons and the rare crude oil are fully mixed in the dilution mixer 31 to form a dilution medium. Compared with the rare crude oil, the dilution medium has a lower viscosity and is better for dilution and viscosity reduction of heavy oil. The amount of dilution medium required to reduce the viscosity of the uniform amplitude is less. The output end of the dilution mixer 31 is connected to the dilution tank 32 through a pipeline. The dilution tank 32 receives the mixed liquid from the dilution mixer 31 and stores it for standby. Specifically, the dilution tank 32 can adopt a conventional pressure-resistant and heat-insulating liquid storage tank for storing the mixed dilution medium, and its input end is connected to the dilution mixer 31 through a pipeline, and the output end is connected to the heater 33 through a pipeline. The heater 33 is arranged on the outlet pipeline of the dilution tank 32, and is used to heat the mixed liquid from the dilution tank and then use it as the dilution medium to be transported to the meter transfer station. The heater 33 can be an electric heater, which is used to heat the dilution medium to a certain temperature to prevent the dilution medium from exchanging heat with the bottom of the well due to the low temperature, which affects the viscosity reduction effect of the heavy oil. The input end of the heater 33 is connected to the dilution tank 32 through a pipeline, and the output end enters the meter transfer station through a pipeline and is then transported to each wellhead for dilution and viscosity reduction of heavy oil.

[0041] Further Figure 2 As shown, the system of the present invention also includes a monitoring control unit 4. The monitoring control unit includes a dynamic viscosity analyzer, a solid particle detector 40, and a ratio controller. Among them, the dynamic viscosity analyzer is arranged at the manifold of the meter transfer station and the inlet of the dilution tank 32, and is used to monitor the viscosity data of the dilution medium and the wellhead produced fluid in real time; the solid particle detector is also arranged at the manifold of the meter transfer station and the inlet of the dilution tank, and is used to monitor the solid phase particle content data in real time. The ratio controller is an executive component in the monitoring control unit 4, which can adjust the addition amount of the asphaltene stabilizer, the ratio of light hydrocarbons / mixed hydrocarbons to rare crude oil, and the addition amount of the dilution medium in real time according to the aforementioned viscosity data and solid phase particle content data.

[0042] like Figure 1 , 2 As shown, the present invention also provides a method for assisting heavy oil production by diluting and reducing viscosity, comprising the following steps:

[0043] Step S101, premixing the light hydrocarbons and mixed hydrocarbons produced by the crude oil production station in a certain proportion for standby use; preferably, but not limiting, before the light hydrocarbons and mixed hydrocarbons are premixed, a processing step of pressurizing the mixed hydrocarbons may also be included;

[0044] Step S102, adding asphaltene stabilizer to the transported rare crude oil for standby use; preferably, but not limiting, the process may also include a step of increasing pressure after the transported rare crude oil is mixed with the asphaltene stabilizer and before use;

[0045] Step S103, the pre-mixed light hydrocarbons and mixed hydrocarbons and the rare crude oil after drug addition are mixed and heated to form a dilution medium, and the dilution medium is transferred to the wellhead through the crude oil production transfer station for heavy oil dilution and viscosity reduction production.

[0046] Furthermore, the present invention provides a dynamic viscosity analyzer and a solid particle detector at each metering station manifold and dilution tank, and during the execution of step S101 to step S103, the viscosity of the dilution medium and the produced fluid and the solid phase particle content can be monitored in real time. Figure 2 The first flow control valve 151), stabilizer (reference Figure 2 The second flow control valve 221), dilute medium (reference Figure 2 The third flow regulating valve 321 in the middle is used to adjust the amount of asphaltene stabilizer added, thereby achieving the purpose of using the monitoring control unit 4 of the present invention to adjust the ratio of light mixed hydrocarbons to thin oil in real time, adjust the addition of thinning medium in real time, and adjust the amount of asphaltene stabilizer added in real time. The monitoring and control are specifically as follows: collecting the viscosity data and solid phase particle content data of the thinning medium and the wellhead produced fluid at the manifold of the meter transfer station and the inlet of the thinning tank; according to the viscosity data and the solid phase particle content data, adjusting the amount of asphaltene stabilizer added, the ratio of light hydrocarbons / mixed hydrocarbons to thin crude oil, and the amount of thinning medium added in real time.

[0047] The specific monitoring and control process is as follows:

[0048] When the incoming thin oil from the outer pipe is unstable and the viscosity of the thin oil is too high, the system of the present invention monitors that the viscosity of the thin medium in the thinning tank 32 is too large, and the monitoring and control unit 4 feeds back a signal to the outlet flow regulating valve of the premixing tank 15 (i.e., the first flow regulating valve 151) to appropriately increase the amount of light mixed hydrocarbons added; when the system monitors that the viscosity of the thin medium is lower than the designed viscosity, the monitoring and control unit 4 feeds back a signal to the outlet flow regulating valve of the premixing tank to appropriately reduce the amount of light mixed hydrocarbons added to save production costs; when the system monitors that the solid phase particle content in the thinning tank 32 increases, the monitoring and control unit 4 feeds back a signal to the outlet flow regulating valve of the stabilizer storage tank 22 (i.e., the second flow regulating valve 221) to appropriately increase the amount of stabilizer added; when the system monitors that the solid phase particle content in the thinning tank 32 is very low, the monitoring and control unit 4 feeds back a signal to the outlet flow regulating valve of the stabilizer storage tank 22 to appropriately reduce the amount of stabilizer added to save production costs.

[0049] When the system detects that the viscosity at the manifold of the meter transfer station is too high and exceeds the design value, the monitoring and control unit 4 feeds back a signal to the flow regulating valve at the outlet of the dilution tank 32 (i.e., the third flow regulating valve 321), and appropriately increases the amount of dilution medium added; when the system detects that the viscosity at the manifold of the meter transfer station is lower than the conventional viscosity range, the monitoring and control unit 4 feeds back a signal to the flow regulating valve at the outlet of the dilution tank 32, and appropriately reduces the amount of dilution medium added to save production costs. When the system detects that the solid phase particle content at the manifold has increased significantly, the monitoring and control unit 4 feeds back a signal to the flow regulating valve at the outlet of the stabilizer storage tank 22 (i.e., the second flow regulating valve 221), and appropriately increases the asphaltene stabilizer content; when the system detects that the solid phase particle content at the manifold is very low or absent, the monitoring and control unit 4 feeds back a signal to the flow regulating valve at the outlet of the stabilizer storage tank 22, and can slowly reduce the amount of asphaltene stabilizer added, observe the changes in the solid phase particles at the manifold, until the solid phase particle content at the manifold begins to rise, and stop reducing the amount of asphaltene stabilizer added to save production costs.

[0050] Example 1

[0051] The viscosity of underground heavy oil in a certain oil field is as high as tens of thousands. The thin oil from the thin oil block of this oil field is used for dilution and viscosity reduction treatment all year round. After viscosity reduction, the crude oil content can be reduced to below 1000mPa.s, and the dilution ratio is 1.86:1. The dilution ratio can be reduced to about 0.5:1 by mixing light mixed hydrocarbons and external thin oil at a ratio of 0.4:1, which effectively reduces the amount of crude oil used for dilution. After a small-scale indoor test, no obvious sedimentation of solid particles such as asphaltene was found during the dilution process.

[0052] Example 2

[0053] The viscosity of produced oil at a certain metering station manifold varies from 500-2000mPa.s, and the viscosity is unstable, with a range of 5000mPa.s-100000mPa.s. Under normal conditions, the light mixed hydrocarbons and the external thin oil are mixed at a ratio of 0.4:1 to form a dilution medium, and the dilution medium is diluted with heavy oil with a viscosity of 10000mPa.s. When the dilution ratio is 0.5:1, the viscosity of produced oil is stable at about 1000mPa.s.

[0054] When the mixed oil viscosity is lower than 500mPa.s, the viscosity of the monitored formation oil is estimated to decrease. The experiment is carried out using formation oil with a viscosity of 5000mPa.s. The dilution ratio is reduced to 0.2:1, and the mixed oil viscosity rises back to 1000mPa.s, which can reduce the amount of dilution medium by 60%.

[0055] When the mixed oil viscosity is higher than 2000mPa.s, the viscosity of the monitored formation oil is estimated to increase. The formation oil with a viscosity of 50000mPa.s is used for the experiment. The dilution ratio of 0.5:1 is kept unchanged. The mixing ratio of light mixed hydrocarbons and external thin oil is increased to 1:1, and the mixed oil viscosity is reduced to 1200mPa.s. It can be seen that when the field conditions are not enough to increase the amount of external thin oil, the mixed oil viscosity can be reduced by increasing the mixing ratio of light mixed hydrocarbons and thin oil.

[0056] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. Any simple modifications, equivalent changes and modifications made to the above exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A system for assisting heavy oil production by diluting and reducing viscosity, characterized in that: include: A light / mixed hydrocarbon premixing unit, which receives light hydrocarbons and mixed hydrocarbons with a certain ratio from a crude oil production joint station and premixes them for standby use; A thin oil dosing unit, which receives the external thin crude oil and adds asphaltene stabilizer for standby use; The diluting medium mixing unit receives the pre-mixed light hydrocarbons and mixed hydrocarbons and the rare crude oil after adding drugs, mixes and heats them to form a diluting medium, and the diluting medium is transported to the wellhead through the crude oil production transfer station for heavy oil dilution and viscosity reduction production.

2. The system for assisting heavy oil production by dilution and viscosity reduction according to claim 1, characterized in that: The light / mixed hydrocarbon premixing unit comprises: a light hydrocarbon tank, which is a liquid insulation storage tank and receives light hydrocarbons from the joint station; A mixed hydrocarbon tank, which is a liquid insulation storage tank and receives mixed hydrocarbons from the joint station; The premixing tank receives the mixed light hydrocarbons and mixed hydrocarbons from the premixer for standby use.

3. The system for assisting heavy oil production by dilution and viscosity reduction according to claim 2 is characterized in that: A first booster pump is arranged between the hydrocarbon mixing tank and the premixer for mixing the boosted mixed hydrocarbon with the light hydrocarbon.

4. The system for assisting heavy oil production by dilution and viscosity reduction according to claim 1, characterized in that: The thin oil dosing unit comprises: A thin oil tank connected to an external thin crude oil pipeline; A stabilizer storage tank, which is used to store asphaltene stabilizer; The dosing tank receives the mixed rare crude oil and asphaltene stabilizer from the dosing mixer and keeps them ready for use.

5. The system for assisting heavy oil production by dilution and viscosity reduction according to claim 4 is characterized in that: A second booster pump is provided on the outlet pipeline of the dosing tank.

6. The system for assisting heavy oil production by dilution and viscosity reduction according to claim 1, characterized in that: The dilute medium mixing unit comprises: A dilution mixer receives the pre-mixed light hydrocarbons and mixed hydrocarbons and the rare crude oil after dosing, and mixes them; A dilution tank, which receives the mixed liquid from the dilution mixer and stores it for standby use; The heater is arranged on the outlet pipeline of the dilution tank and is used to heat the mixed liquid from the dilution tank and then use it as the dilution medium.

7. The system for assisting heavy oil production by dilution and viscosity reduction according to claim 1, characterized in that: The system further comprises a monitoring control unit, which comprises: Dynamic viscosity analyzer, which is installed at the manifold of the metering station and the inlet of the dilution tank, is used to monitor the viscosity data of the dilution medium and the wellhead produced fluid in real time; Solid particle detector, which is installed at the manifold of the metering station and the entrance of the dilution tank, is used to monitor the solid phase particle content data in real time; A ratio controller adjusts the amount of asphaltene stabilizer added, the ratio of light hydrocarbons / mixed hydrocarbons to rare crude oil, and the amount of diluent added in real time according to the viscosity data and the solid phase particle content data.

8. A method for assisting heavy oil production by diluting and reducing viscosity, characterized in that: The steps include: A. Premix the light hydrocarbons and mixed hydrocarbons produced by the crude oil production joint station in a certain proportion for standby use; B. Add asphaltene stabilizer to the exported rare crude oil for later use; C. The pre-mixed light hydrocarbons and mixed hydrocarbons and the rare crude oil after drug addition are mixed and heated to form a dilution medium, and the dilution medium is transferred to the wellhead through the crude oil production transfer station for heavy oil dilution and viscosity reduction production.

9. The method for assisting heavy oil production by dilution and viscosity reduction according to claim 8, characterized in that: Before the light hydrocarbons and the mixed hydrocarbons are premixed in step A, a processing step of pressurizing the mixed hydrocarbons is also included.

10. The method for assisting heavy oil production by dilution and viscosity reduction according to claim 8, characterized in that: In the step B, after the asphaltene stabilizer is added to the imported rare crude oil for mixing and before use, a pressure-raising treatment step is also included.

11. The method for assisting heavy oil production by dilution and viscosity reduction according to claim 8, characterized in that: The method further comprises a monitoring and control step, which specifically comprises: Collect the viscosity data and solid particle content data of the dilution medium at the manifold of the meter transfer station and the inlet of the dilution tank and the produced fluid at the wellhead; According to the viscosity data and the solid phase particle content data, the addition amount of the asphaltene stabilizer, the ratio of light hydrocarbons / mixed hydrocarbons to rare crude oil, and the addition amount of the diluent medium are adjusted in real time.

12. The method for assisting heavy oil production by dilution and viscosity reduction according to claim 11, characterized in that: The amount of asphaltene stabilizer added, the ratio of light hydrocarbons / mixed hydrocarbons to rare crude oil, and the amount of diluent added are controlled by flow regulating valves at corresponding positions.

13. The method for assisting heavy oil production by dilution and viscosity reduction according to claim 12, characterized in that: After monitoring and controlling the ratio, the dilution ratio of light / mixed hydrocarbons to exported rare crude oil is 0.5:1; the viscosity of produced oil is below 1000mPa.s.

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