Diluting and Viscosity Reduction Assisted Heavy Oil Extraction System and Method

Abstract

This invention discloses a system and method for thickening and viscosity-reducing heavy oil extraction. The system includes: a light / mixed hydrocarbon premixing unit, which receives light hydrocarbons and mixed hydrocarbons in a certain proportion from an oilfield extraction station and premixes them for later use; a thinning agent dosing unit, which receives exported rare crude oil and adds asphaltene stabilizer for later use; and a thinning medium mixing unit, which receives the premixed light hydrocarbons and mixed hydrocarbons and the doped rare crude oil, mixes them, and heats them to form a thinning medium. This thinning medium is transported to the wellhead via an oilfield extraction transfer station for thickening and viscosity-reducing extraction of heavy oil. This invention uses light hydrocarbons and mixed hydrocarbons produced by an oilfield extraction station, mixed with rare crude oil containing asphaltene stabilizer in a certain proportion to form a thinning medium, which not only effectively reduces the viscosity of heavy oil but also requires a lower amount of rare crude oil.

Description

Technical Field

[0001] This invention relates to the field of heavy oil extraction technology, and in particular to a system and method for using light hydrocarbons and mixed hydrocarbons generated during on-site extraction to dilute and reduce viscosity to assist in heavy oil extraction. Background Technology

[0002] After years of development and utilization, the production of conventional crude oil has gradually decreased, while the production share of unconventional oil reservoirs such as heavy oil has been increasing year by year, and the development and utilization of heavy oil has received increasing attention. A major problem in the extraction of heavy oil is its high viscosity. Due to its poor quality, heavy oil contains a large amount of asphaltenes and gums, resulting in extremely high viscosity and poor fluidity, making it difficult to extract from the well bottom. Therefore, excessively high crude oil viscosity is the most significant obstacle to heavy oil extraction.

[0003] Currently, the main methods for reducing the viscosity of heavy crude oil include chemical viscosity reduction and physical viscosity reduction. Chemical viscosity reduction involves adding chemical agents to alter the molecular structure of heavy crude oil, thereby reducing its viscosity. However, due to the high cost of these agents and their potential for pollution, it poses additional challenges to the subsequent processing and utilization of crude oil. In contrast, physical viscosity reduction has a smaller impact on the environment and the properties of the 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 oilfields for heavy oil viscosity reduction. For conventional or general heavy oil reservoirs, the crude oil viscosity is not high, and appropriate heating can meet the process requirements. However, for extra-heavy and extra-heavy oil reservoirs, relying solely on heating viscosity reduction requires raising the temperature by tens of degrees Celsius, or even hundreds of degrees Celsius, which not only consumes a lot of industrial energy and is very costly, but also poses problems for construction and operational safety. Therefore, for extremely viscous extra-heavy / extra-heavy oils, while heating viscosity reduction, an appropriate amount of thinner is added to the crude oil to achieve the effect of reducing crude oil viscosity.

[0005] However, diluting and reducing viscosity requires a large amount of rare crude oil, and transporting rare oil requires an additional rare oil gathering and transportation system. Relying solely on external rare oil for diluting and reducing viscosity is costly.

[0006] Therefore, there is an urgent need for a system and method for thick oil blending and viscosity reduction that can effectively reduce the amount of rare crude oil used while ensuring the reduction in crude oil viscosity.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide a system and method for assisting heavy oil extraction by using light hydrocarbons and mixed hydrocarbons produced in the field to dilute and reduce viscosity. The light hydrocarbons and mixed hydrocarbons produced by the oilfield joint station are mixed with rare crude oil with added asphaltene stabilizer in a certain proportion to form a diluent medium, which can not only effectively reduce the viscosity of heavy oil, but also reduce the amount of rare crude oil used.

[0009] Another objective of this invention is to dynamically monitor changes in the viscosity of the outer tube thin oil and produced oil, as well as the precipitation of asphaltene, and to adjust the dosage of light hydrocarbons, mixed hydrocarbons, and asphaltene stabilizers in real time, thereby achieving the best technical and economic results.

[0010] To achieve the above objectives, according to a first aspect of the present invention, the present invention provides a system for thickening and viscosity-reducing heavy oil extraction, comprising: a light / mixed hydrocarbon premixing unit, which receives light hydrocarbons and mixed hydrocarbons in a certain proportion from an oil extraction joint station and premixes them for later use; a thinning agent dosing unit, which receives exported rare crude oil and adds asphaltene stabilizer for later use; and a thinning medium mixing unit, which receives the premixed light hydrocarbons and mixed hydrocarbons and the doped rare crude oil, mixes them, and heats them to form a thinning medium, which is then transported to the wellhead via an oil extraction transfer station for thick oil thickening and viscosity-reducing extraction.

[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 light hydrocarbons and mixed hydrocarbons mixed from the premixer and keeps them for later use.

[0012] Furthermore, in the above technical solution, a first booster pump can be installed between the mixing tank and the premixer to mix the pressurized mixed hydrocarbons with the light hydrocarbons.

[0013] Furthermore, in the above technical solution, the thin oil dosing unit may include: a thin oil tank, which is connected to an external thin crude oil pipeline; a stabilizer storage tank, which is used to store asphaltene stabilizer; and a dosing tank, which receives and keeps the thin crude oil and asphaltene stabilizer mixed from the dosing mixer.

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

[0015] Furthermore, in the above technical solution, the diluent mixing unit may include: a diluent mixer, which receives and mixes the premixed light hydrocarbons and mixed hydrocarbons as well as the added crude oil; a diluent tank, which receives the mixed liquid from the diluent mixer and stores it for later use; and a heater, which is installed on the outlet pipeline of the diluent tank and is used to heat the mixed liquid from the diluent tank for use as a diluent medium.

[0016] Furthermore, in the above technical solution, the viscosity-reducing auxiliary heavy oil extraction system may also include a monitoring and control unit, which may specifically include: a dynamic viscosity analyzer, which is installed at the metering and transfer station manifold and the inlet of the diluent tank, for real-time monitoring of the viscosity data of the diluent medium and the wellhead produced fluid; a solid particle detector, which is installed at the metering and transfer station manifold and the inlet of the diluent tank, for real-time monitoring of solid particle content data; and a proportioning controller, which adjusts the amount of asphaltene stabilizer added, the proportion of light hydrocarbons / mixed hydrocarbons and rare crude oil, and the amount of diluent medium added in real-time based on the viscosity data and solid particle content data.

[0017] According to a second aspect of the present invention, the present invention provides a method for heavy oil extraction assisted by dilution and viscosity reduction, comprising the following steps: A. Premixing light hydrocarbons and mixed hydrocarbons produced by a crude oil extraction station in a certain proportion for later use; B. Adding asphaltene stabilizer to exported rare crude oil for later use; C. Mixing the premixed light hydrocarbons and mixed hydrocarbons with the rare crude oil after adding the stabilizer and heating to form a dilution medium, and transporting the dilution medium to the wellhead through a crude oil extraction transfer station for heavy oil dilution and viscosity reduction extraction.

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

[0019] Furthermore, in the above technical solution, step B, after the imported rare crude oil is mixed with asphaltene stabilizer and before use, may also include a pressurization treatment step.

[0020] Furthermore, in the above technical solution, the method for assisting heavy oil extraction by dilution and viscosity reduction may also include a monitoring and control step. This monitoring and control step specifically involves: collecting viscosity data and solid particle content data of the diluent and produced fluid at the manifold of the metering station and the inlet of the diluent tank; and adjusting the amount of asphaltene stabilizer, the ratio of light hydrocarbons / mixed hydrocarbons to rare crude oil, and the amount of diluent added in real time based on the viscosity data and 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 the flow regulating valve at the corresponding location.

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

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

[0024] 1) This invention reduces the viscosity of the diluent by adding light hydrocarbons and mixed hydrocarbons to crude oil, thus improving the viscosity reduction effect of heavy oil dilution. By making full use of the light hydrocarbons and mixed hydrocarbons produced on-site in the oil field, the amount of crude oil exported can be effectively reduced, saving the extraction cost of heavy oil dilution and viscosity reduction.

[0025] 2) This invention prevents the precipitation of crude oil asphaltenes due to changes in crude oil composition during the blending of light hydrocarbons by adding a small amount of asphaltenes stabilizer, making the blending and viscosity reduction of heavy oil safer and more stable.

[0026] 3) This invention dynamically monitors the liquid phase viscosity and solid particle content at the manifold of the metering station and the inlet of the diluent tank, and dynamically controls the diluent ratio. That is, the amount of light / mixed hydrocarbons and stabilizers added can be dynamically adjusted according to the diluent medium, the viscosity of the produced oil and the solid particle content, so as to save production costs as much as possible while ensuring the stability of the properties of the produced fluid.

[0027] 4) The process flow of the present invention for thick oil extraction by dilution and viscosity reduction is simple and easy to operate.

[0028] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the connection of the viscosity-reducing heavy oil extraction system of the present invention.

[0030] Figure 2 This is a schematic diagram of the connection of the monitoring and control unit in the heavy oil extraction system for dilution and viscosity reduction of the present invention.

[0031] Explanation of key figure labels:

[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-Dilute oil dosing unit, 21-Dilute oil tank, 22-Stabilizer storage tank, 221-Second flow regulating valve, 23-Dosing mixer, 24-Dosing tank, 25-Second booster pump, 3-Diluted medium mixing unit, 31-Diluted mixer, 32-Diluted tank, 321-Third flow regulating valve, 33-Heater, 4-Monitoring and control unit, 40-Dynamic viscosity analyzer and solid particle detector. Detailed Implementation

[0033] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0034] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0035] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein 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 define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0037] like Figure 1 As shown, this invention provides a system for thickening and viscosity-reducing heavy oil extraction, comprising a light / mixed hydrocarbon premixing unit 1, a thin oil dosing unit 2, and a thinning medium mixing unit 3. The light / mixed hydrocarbon premixing unit 1 receives light hydrocarbons and mixed hydrocarbons in a certain proportion from the crude oil extraction station and premixes them for later use. The thin oil dosing unit 2 receives exported rare crude oil and adds asphaltene stabilizer for later use. The thinning medium mixing unit 3 receives the premixed light hydrocarbons and mixed hydrocarbons, as well as the dosed rare crude oil, mixes them, and heats them to form a thinning medium. This thinning medium is then transported to the wellhead via the crude oil extraction transfer station for thick oil thickening and viscosity-reducing extraction. The system of this invention can use light hydrocarbons and mixed hydrocarbons produced on-site in oilfields for the process of thickening and reducing the viscosity of heavy oil. In this process, the light hydrocarbons and mixed hydrocarbons produced by the oilfield joint station are mixed with thin crude oil containing asphaltene stabilizers in a certain proportion. The resulting thinning medium can more effectively reduce the viscosity of heavy oil and improve its fluidity. Moreover, the amount of thin crude oil used is lower, and some of the light hydrocarbons and mixed hydrocarbons can be recycled and reused at the joint station, saving the cost of heavy oil extraction.

[0038] Further as 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. The light hydrocarbon tank 11 is a liquid insulated storage tank that receives light hydrocarbons from the combined 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 combined station's external light hydrocarbon pipeline via a pipeline. The light hydrocarbon tank 11 has a certain pressure resistance and insulation rating to ensure that the light hydrocarbons inside 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 outlet. The output end of the light hydrocarbon tank 11 is connected to the premixer 14 via a pipeline. The mixed hydrocarbon tank 12 is a liquid insulated storage tank that receives mixed hydrocarbons from the combined station. Specifically, the mixed hydrocarbon tank 12 is also a pressure-resistant insulated liquid storage tank with a certain volume. The input end of the mixed hydrocarbon tank 12 is connected to the combined station's external mixed hydrocarbon pipeline via a pipeline, and the output end of the mixed hydrocarbon tank 12 is connected to the first booster pump 13 via a pipeline. The first booster pump can be a conventional liquid booster pump, with its input end connected to the hydrocarbon mixing tank 12 and its output end connected to the premixer 14. The first booster pump 13 can bring the pressure of the hydrocarbons flowing out of the hydrocarbon mixing tank to a corresponding level to facilitate mixing with light hydrocarbons. The premixing tank 15 receives the light hydrocarbons and hydrocarbons mixed from the premixer 14 and keeps them for later use. The premixer 14 can be a static mixer, with its input end connected to the first booster pump 13 and the light hydrocarbon tank 11 respectively through pipelines. The hydrocarbons delivered by the first booster pump 13 and the light hydrocarbons delivered by the light hydrocarbon tank 11 are mixed in the premixer 14 at a certain ratio. After complete mixing, the hydrocarbons are discharged from the output end of the premixer 14, which is connected to the premixing tank 15 through a pipeline. The premixing tank 15 is a conventional pressure-resistant and heat-insulated storage tank used to store the mixed hydrocarbons after the light hydrocarbons and hydrocarbons are mixed. The input end of the premixing tank 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 as Figure 1As shown, the thin oil dosing unit includes a thin oil tank 21, a stabilizer storage tank 22, and a dosing tank 24. The thin oil tank 21 is connected to an external thin crude oil pipeline. Specifically, the thin oil tank 21 can be a conventional pressure-resistant and insulated crude oil storage tank, with its inlet connected to the external thin crude oil pipeline and its outlet connected to the dosing mixer 23 via a pipeline. The stabilizer storage tank 22 is used to store asphaltene stabilizer. Specifically, the stabilizer storage tank can be a conventional pressure-resistant and insulated liquid phase storage tank. The finished stabilizer is added to the stabilizer storage tank 22 through its inlet and stored inside. The stabilizer storage tank 22's outlet is connected to the dosing mixer 23 via a pipeline. The dosing tank 24 receives the mixed thin crude oil and asphaltene stabilizer from the dosing mixer 23 and keeps it ready for use. Specifically, the dosing mixer 23 can be a static mixer, with its input end connected to the thin oil tank 21 and the stabilizer storage tank 22 via pipelines. Asphaltene stabilizer and crude oil of a certain grade flow into the dosing mixer 23 for mixing. The fully mixed liquid crude oil is discharged from the output end of the dosing mixer 23, which is connected to the dosing tank 24 via a pipeline. Preferably, but not limitingly, 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, with its input end connected to the dosing tank 24. This second booster pump 25 can bring the pressure of the crude oil of a certain grade flowing out of the dosing tank 24 to a certain level, so as to facilitate mixing with the liquid flowing out of the light / mixed hydrocarbon premixing unit. The output end of the second booster pump 25 enters the diluent mixing unit 3 via a pipeline.

[0040] Further as Figure 1As shown, the diluent mixing unit includes a diluent mixer 31, a diluent tank 32, and a heater 33. The diluent mixer 31 receives premixed light hydrocarbons and mixed hydrocarbons, as well as chemically treated crude oil, and mixes them. Specifically, the diluent mixer 31 can be a conventional static mixer, with its input end connected to the light / mixed hydrocarbon premixing unit 1 and the crude oil chemical treatment unit 2 via pipelines. The mixed hydrocarbons and crude oil are thoroughly mixed within the diluent mixer 31 to form a diluent medium. This diluent medium has a lower viscosity than the crude oil, resulting in better viscosity reduction for heavy oil and requiring less diluent medium to achieve a uniform viscosity reduction. The output end of the diluent mixer 31 is connected to the diluent tank 32 via a pipeline. The diluent tank 32 receives the mixed liquid from the diluent mixer 31 and stores it for later use. Specifically, the diluent tank 32 can be a conventional pressure-resistant and heat-insulated liquid storage tank used to store the mixed diluent medium. Its input end is connected to the diluent mixer 31 via a pipeline, and its output end is connected to the heater 33 via a pipeline. Heater 33 is installed on the outlet pipeline of diluent tank 32 to heat the mixed liquid from the diluent tank before it is used as a diluent medium to be transported to the metering station. Heater 33 can be an electric heater to heat the diluent medium to a certain temperature to prevent the diluent medium temperature from being too low and affecting the viscosity reduction effect of the heavy oil at the bottom of the well when heat exchange occurs. The input end of heater 33 is connected to diluent tank 32 through a pipeline, and the output end enters the metering station through a pipeline and is then transported to each wellhead for heavy oil diluenting and viscosity reduction production.

[0041] Further as Figure 2 As shown, the system of the present invention also includes a monitoring and control unit 4. The monitoring and control unit includes a dynamic viscosity analyzer, a solid particle detector 40, and a proportioning controller. The dynamic viscosity analyzer is installed at the manifold of the metering station and at the inlet of the diluent tank 32, and is used to monitor the viscosity data of the diluent and the wellhead produced fluid in real time. The solid particle detector is also installed at the manifold of the metering station and at the inlet of the diluent tank, and is used to monitor the solid particle content data in real time. The proportioning controller is the actuating component in the monitoring and control unit 4, and can adjust the amount of asphaltene stabilizer added, the proportion of light hydrocarbons / mixed hydrocarbons to rare crude oil, and the amount of diluent added in real time according to the aforementioned viscosity data and solid particle content data.

[0042] like Figure 1 , 2 As shown, the present invention also provides a method for heavy oil extraction assisted by dilution and viscosity reduction, comprising the following steps:

[0043] Step S101: Premix the light hydrocarbons and mixed hydrocarbons produced by the crude oil extraction station in a certain proportion for later use; preferably, but not limitingly, before premixing the light hydrocarbons and mixed hydrocarbons, a step of pressurizing the mixed hydrocarbons may also be included.

[0044] Step S102: Add asphaltene stabilizer to the exported rare crude oil for later use; preferably, but not limitingly, a pressurization treatment step may also be included after the exported rare crude oil is mixed with asphaltene stabilizer and before use.

[0045] Step S103: The premixed light hydrocarbons and mixed hydrocarbons, along with the chemically treated crude oil, are mixed and heated to form a diluent. The diluent is then transported to the wellhead via the crude oil extraction transfer station for heavy oil dilution and viscosity reduction extraction.

[0046] Furthermore, this invention includes dynamic viscosity analyzers and solid particle detectors at each metering station manifold and dilution tank. During steps S101 to S103, the viscosity and solid particle content of the dilution medium and produced fluid can be monitored in real time. Light hydrocarbon mixtures are controlled using flow regulating valves (see reference). Figure 2 First flow regulating valve 151), stabilizer (reference) Figure 2 Second flow regulating valve 221), dilute medium (reference) Figure 2 The third flow regulating valve 321) is used to adjust the amount of light hydrocarbon / mixed hydrocarbon and thin oil added, thereby achieving the purpose of adjusting the ratio of light hydrocarbon / mixed hydrocarbon and thin oil, adjusting the addition of thinning medium, and adjusting the amount of asphaltene stabilizer added in real time using the monitoring and control unit 4 of the present invention. The monitoring and control specifically involves: collecting viscosity data and solid particle content data of the thinning medium and wellhead produced fluid at the manifold of the metering station and the inlet of the thinning tank; and adjusting the amount of asphaltene stabilizer added, the ratio of light hydrocarbon / mixed hydrocarbon and thin crude oil, and the amount of thinning medium added in real time based on the viscosity data and solid particle content data.

[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 this invention detects that the viscosity of the thinning medium in the thinning tank 32 is too high. The monitoring and control unit 4 sends a feedback signal to the outlet flow regulating valve (i.e., the first flow regulating valve 151) of the premixing tank 15 to appropriately increase the amount of light mixed hydrocarbons added. When the system detects that the viscosity of the thinning medium is lower than the design viscosity, the monitoring and control unit 4 sends a feedback 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 detects that the content of solid particles in the thinning tank 32 is increasing, the monitoring and control unit 4 sends a feedback signal to the outlet flow regulating valve (i.e., the second flow regulating valve 221) of the stabilizer storage tank 22 to appropriately increase the amount of stabilizer added. When the system detects that the content of solid particles in the thinning tank 32 is very low, the monitoring and control unit 4 sends a feedback 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 metering station is too high, exceeding the design value, the monitoring and control unit 4 sends a feedback signal to the outlet flow regulating valve of the diluent tank 32 (i.e., the third flow regulating valve 321) to appropriately increase the amount of diluent added. When the system detects that the viscosity at the manifold of the metering station is lower than the normal viscosity range, the monitoring and control unit 4 sends a feedback signal to the outlet flow regulating valve of the diluent tank 32 to appropriately decrease the amount of diluent added, in order to save production costs. When the system detects that the solid particle content at the manifold has increased significantly, the monitoring and control unit 4 sends a feedback 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 asphalt stabilizer content. When the system detects that the solid particle content at the manifold is very low or non-existent, the monitoring and control unit 4 sends a feedback signal to the outlet flow regulating valve of the stabilizer storage tank 22 to slowly reduce the amount of asphalt stabilizer added, observe the change in solid particles at the manifold, until the solid particle content at the manifold begins to increase, and then stop reducing the amount of asphalt stabilizer added, in order to save production costs.

[0050] Example 1

[0051] The viscosity of heavy oil in a certain oilfield reaches tens of thousands. For many years, thin oil from the oilfield's light oil block has been used for blending to reduce viscosity, lowering the crude oil content to below 1000 mPa·s at a blending ratio of 1.86:1. By mixing light hydrocarbons with exported light oil at a ratio of 0.4:1, the blending ratio can be further reduced to approximately 0.5:1, effectively decreasing the amount of crude oil used for blending. Small-scale indoor tests showed no significant settling of asphaltene or other solid particles during the blending process.

[0052] Example 2

[0053] The viscosity of produced oil at a certain transfer station manifold varies from 500 to 2000 mPa·s, exhibiting instability with a range between 5000 mPa·s and 100000 mPa·s. Under normal conditions, light hydrocarbons are blended with export light oil at a ratio of 0.4:1 to form a diluent. This diluent is then blended with heavy oil with a viscosity of 10000 mPa·s. When the diluent ratio is 0.5:1, the viscosity of the produced oil stabilizes at around 1000 mPa·s.

[0054] When the viscosity of the mixed oil is below 500 mPa·s, the viscosity of the formation oil is expected to decrease. An experiment was conducted using formation oil with a viscosity of 5000 mPa·s. When the dilution ratio was reduced to 0.2:1, the viscosity of the mixed oil rose back to 1000 mPa·s, which can reduce the amount of dilution medium used by 60%.

[0055] When the viscosity of the mixed oil exceeds 2000 mPa·s, an increase in the viscosity of the formation oil is predicted. An experiment was conducted using formation oil with a viscosity of 50000 mPa·s. Maintaining a constant dilution ratio of 0.5:1, the mixing ratio of light hydrocarbons to export thin oil was increased to 1:1, resulting in a decrease in the mixed oil viscosity to 1200 mPa·s. This demonstrates that when on-site conditions are insufficient to increase the export volume of thin oil, the viscosity of the mixed oil can be reduced by increasing the mixing ratio of light hydrocarbons to thin oil.

[0056] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A system for exploiting thickened oil with the aid of dilution and viscosity reduction, characterized in that, The system comprises: a light / hydrocarbon mixture pre-mixing unit receiving light hydrocarbons and mixed hydrocarbons with a certain proportion from a crude oil production joint station and pre-mixing them for standby, wherein the light hydrocarbons and mixed hydrocarbons are produced on site; a thin oil dosing unit receiving thin oil crude oil for external transportation and adding asphaltene stabilizer for standby; a thin oil medium mixing unit receiving the pre-mixed light hydrocarbons and mixed hydrocarbons and the dosed thin oil crude oil, mixing and heating them to form a thin oil medium, and transporting the thin oil medium to a wellhead through a crude oil production metering station for heavy oil thinning and viscosity reduction production; a monitoring and control unit comprising a dynamic viscosity analyzer arranged at a metering station manifold and a thin oil tank inlet for real-time monitoring of viscosity data of the thin oil medium and wellhead produced liquid, and a solid particle detector arranged at the metering station manifold and the thin oil tank inlet for real-time monitoring of solid particle content data; a proportioning controller for real-time adjustment of the amount of asphaltene stabilizer added, the proportion of light hydrocarbons / mixed hydrocarbons and thin oil crude oil, and the amount of thin oil medium added according to the viscosity data and the solid particle content data.

2. The system according to claim 1, wherein, The light / hydrocarbon mixture pre-mixing unit comprises: a light hydrocarbon tank which is a liquid heat preservation storage tank and receives light hydrocarbons from the joint station; a mixed hydrocarbon tank which is a liquid heat preservation storage tank and receives mixed hydrocarbons from the joint station; a pre-mixing tank which receives mixed light hydrocarbons and mixed hydrocarbons from a pre-mixer for standby.

3. The system according to claim 2, wherein, A first booster pump is arranged between the mixed hydrocarbon tank and the pre-mixer to mix the boosted mixed hydrocarbons with the light hydrocarbons.

4. The system according to claim 1, wherein, The thin oil dosing unit comprises: a thin oil tank connected with an external thin oil pipeline; a stabilizer storage tank for storing asphaltene stabilizer; a dosing tank receiving the mixed thin oil crude oil and asphaltene stabilizer from a dosing mixer for standby.

5. The system according to claim 4, wherein the system further comprises a pump for pumping the dilute solution into the well. A second booster pump is arranged on the dosing tank outlet pipeline.

6. The system according to claim 1, wherein, The thin oil medium mixing unit comprises: a thin oil mixer receiving the pre-mixed light hydrocarbons and mixed hydrocarbons and the dosed thin oil crude oil and mixing them; a thin oil tank receiving mixed liquid from the thin oil mixer for standby; a heater arranged on the outlet pipeline of the thin oil tank for heating the mixed liquid from the thin oil tank to be used as a thin oil medium.

7. A method for exploiting thickened oil with the aid of dilution and viscosity reduction, characterized by, The system according to any one of claims 1 to 6 comprises the following steps: A. Pre-mixing light hydrocarbons and mixed hydrocarbons produced by a crude oil production joint station in a certain proportion for standby; B. Adding asphaltene stabilizer to thin oil crude oil for external transportation for standby; C. Mixing and heating the pre-mixed light hydrocarbons and mixed hydrocarbons and the dosed thin oil crude oil to form a thin oil medium, and transporting the thin oil medium to a wellhead through a crude oil production metering station for heavy oil thinning and viscosity reduction production.

8. The method according to claim 7, wherein the method is characterized by, The light hydrocarbons and mixed hydrocarbons in step A are pre-mixed, and the mixed hydrocarbons are boosted before pre-mixing.

9. The method according to claim 7, wherein the method is characterized by, The thin oil crude oil for external transportation in step B is mixed with asphaltene stabilizer, and the mixed thin oil crude oil is boosted before use.

10. The method according to claim 7, wherein the method is characterized by, The method further comprises a monitoring and control step, which is specifically: collecting viscosity data and solid particle content data of the thin oil medium and wellhead produced liquid at the metering station manifold and the thin oil tank inlet; According to the viscosity data and the solid phase particle content data, the addition amount of asphaltene stabilizer, the ratio of light hydrocarbon / mixed hydrocarbon to thin crude oil and the addition amount of thinning medium are adjusted in real time.

11. The method according to claim 10, wherein the method is characterized by, The addition amount of asphaltene stabilizer, the ratio of light hydrocarbon / mixed hydrocarbon to thin crude oil and the addition amount of thinning medium are controlled by flow regulating valves at corresponding positions.

12. The method according to claim 11, wherein the method is characterized by, After monitoring and controlling the ratio, the mixing ratio of light / mixed hydrocarbon to thin crude oil for external transportation is 0.5:1, and the viscosity of produced oil is below 1000 mPa.s.

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