Non-heating oil gathering and water mixing optimization system and method for heavy oil field

Abstract

The invention provides a non-heating oil gathering and water mixing optimization system and method for a heavy oil field. The non-heating oil gathering and water mixing optimization method for the heavy oil field comprises the following steps: step 1, defining a wall adhesion deposition temperature; step 2, deriving a thick oil wall-adhering deposition temperature calculation formula, and calculating a wall-adhering deposition temperature value T1; 3, calculating the oil temperature T2 of the tail point of the gathering and transportation pipeline; 4, the wall sticking deposition temperature T1 and the tail point oil temperature T2 of the pipeline are judged, and when T1 is larger than or equal to T2, the lowest starting point oil temperature TRmin of the pipeline is inversely calculated; 5, the watering temperature and the watering amount under the TRmin temperature condition are obtained through calculation. According to the non-heating oil gathering and water mixing optimization system and method for the heavy oil field, the problem of high energy consumption of heavy oil gathering and transportation can be well solved, and solid theoretical guidance is provided for heavy oil water mixing gathering and transportation.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield surface gathering and transportation research, and in particular to an unheated oil gathering and water mixing optimization system and method for heavy oil fields. Background Art

[0002] Due to its high viscosity, high density and poor fluidity, heavy oil requires appropriate means of reducing viscosity and drag to maintain safe gathering and transportation. Considering the cost and convenience, the method of mixing with heated produced wastewater is often used on site. At the same time, most of my country's oil fields have entered the middle and late stages of development, and the water content of wellhead produced fluid is constantly increasing. Continuing to use hot water mixing for gathering and transportation greatly increases the energy consumption of gathering and transportation.

[0003] At the same time, high water content also changes the flow characteristics of the oil-water two-phase. Specifically, the heavy oil is mostly suspended or floated in the water phase in the form of gelled oil blocks, which creates conditions for non-heating gathering and transportation. However, in the process of non-heating gathering and transportation, there is a critical temperature for wall adhesion and siltation, and the temperature at the end of the return oil pipeline must be higher than this temperature limit to maintain safe gathering and transportation.

[0004] At present, many scholars have studied the unheated gathering and transportation process and formed a variety of calculation methods for the parameters of the unheated gathering and transportation process. In 2016, Yang Zhengran conducted a study on the gathering and transportation radius of the fire-driven heavy oil block in the article "Research on Critical Conditions for Surface Gathering and Transportation of Heavy Oil in High Water Cut Period of Liaohe Oilfield". The technical route is to use PIPEPHASE software to establish a gathering and transportation model, select the Beggs & Brill-Moody (BBM) model as the pressure drop calculation method in the simulation calculation, and set the black oil model as the fluid in the pipe. The basis for calculating the gathering and transportation radius is stipulated as a pressure drop of less than 0.2MPa, and the gathering and transportation radius under different oil gathering temperature conditions is calculated respectively.

[0005] In 2020, Huang Zuonan calculated the theoretical value of the total heat transfer coefficient in the thermal model of the oil gathering pipeline based on the relevant principles of heat transfer in the article "Research on Thermal-Hydraulic Characteristics of Multiphase Mixed Transportation Pipelines in Oil Fields and Calculation Method of Normal Temperature Gathering and Transportation Radius", and used MATLAB software to correct the total. At the same time, combined with multiphase flow theory, a thermal-hydraulic model of the mixed transportation pipeline was constructed, and its thermal-hydraulic characteristics were analyzed. Finally, the normal temperature gathering and transportation radius was determined through temperature drop and pressure drop coupling calculation.

[0006] Compared with these two documents, this technical patent takes the gathering and transportation temperature higher than the wall adhesion deposition temperature as the restriction condition, and focuses on the optimization and regulation of the water addition amount and water addition temperature.

[0007] In 2011, Si Minglin determined the safe oil return temperature limit under the corresponding working conditions in the article "Research on Low-temperature Gathering and Transportation Limits and Process Parameter Optimization of Satellite Oilfield" based on the simulation in the low-temperature gathering and transportation room. It was determined that when the water content of the oil return system is 70%, the safe oil return temperature value should be controlled at 1-2°C above the freezing point of crude oil; when the water content is above 90% and the corresponding flow rate is controlled at about 0.25m / s, the safe oil return temperature limit can be reduced to 3-5°C below the freezing point of crude oil. It uses a two-level hierarchical optimization method to optimally determine the low-temperature water-blending gathering and transportation process operating parameters of all oil gathering rings under the jurisdiction of the oilfield based on the safe oil return temperature limit and the production and operation costs of the oil transfer station system. Different from this document, the safe oil return temperature of this patent is the wall sticking siltation temperature, and its value is relatively accurate and can be calculated through the model.

[0008] In the Chinese patent application with application number: CN202010023832.0, a method, device and storage medium for determining water-injection oil-collecting parameters are involved, which belongs to the technical field of oil and gas production. The method includes: determining the temperature drop model of the oil-collecting pipeline between each node according to the node parameters of each node in the oil-collecting pipeline network, wherein each node includes a joint station, a plurality of metering stations and a plurality of single wells corresponding to each metering station in the oil-collecting pipeline network; determining a plurality of water-injection temperatures and a plurality of water-injection amounts according to the temperature drop model and constraints, wherein the constraints are used to constrain the thermal energy consumption, temperature and pressure of the oil-collecting pipeline; determining the optimal water-injection amount and the optimal water-injection temperature from the plurality of water-injection temperatures and the plurality of water-injection amounts through a genetic algorithm. The present application can determine the optimal water-injection temperature and water-injection amount through the temperature drop model and constraints, thereby eliminating the need for frequent adjustments by staff, improving the efficiency of oil and water transportation, and realizing closed-loop regulation of the water-injection amount under low energy consumption conditions.

[0009] In the Chinese patent application with application number: CN201811536185.2, a control method, device and storage medium for water injection parameters of an annular crude oil gathering and transportation system are involved, which belongs to the technical field of water injection and oil gathering in oil fields. The method is applied to the water injection control system, including obtaining the operating parameters of the annular crude oil gathering and transportation system through a data collector at preset time intervals, obtaining the daily energy consumption model of the annular crude oil gathering and transportation system including the water injection temperature variable and the water injection amount variable through a processor according to these parameters, and determining the target water injection parameters that meet the preset constraints and minimize the daily energy consumption of the annular crude oil gathering and transportation system according to the daily energy consumption model and preset constraints, and finally, controlling the adjustment of the water injection parameters of the annular crude oil gathering and transportation system through the heating furnace temperature controller and the water injection pump control inverter. According to this method, the water injection control system can realize the function of automatically and quickly controlling the water injection parameters in the annular crude oil gathering and transportation system, ensuring that the daily energy consumption of the annular crude oil gathering and transportation system is always at the lowest value.

[0010] The above existing technologies are greatly different from the present invention and fail to solve the technical problems we want to solve. Therefore, we have invented a new non-heated oil collection and water mixing optimization system and method for heavy oil fields. Summary of the invention

[0011] The purpose of the present invention is to provide a non-heating oil gathering and water mixing optimization system and method for heavy oil fields that can accurately determine the water mixing parameters in the gathering and transportation process of each heavy oil well, so as to solve the problem that the water mixing parameters are difficult to determine in the current heavy oil gathering and transportation process, resulting in energy waste, and reduce the energy consumption of heavy oil gathering and transportation.

[0012] The object of the present invention can be achieved through the following technical measures: an unheated oil gathering and water doping optimization system for a heavy oil field, the unheated oil gathering and water doping optimization system for a heavy oil field comprising a remote pressure gauge, a remote temperature gauge, a gate valve, a single well oil return pipeline, a transparent glass tube, an oil gathering manifold, a mass flow meter, a water doping manifold and a single well water doping pipeline, the remote pressure gauge, the remote temperature gauge and the gate valve are connected in sequence and connected to the single well oil return pipeline, the single well oil return pipeline is connected to the oil gathering manifold, the mass flow meter is connected to the gate valve through the single well water doping pipeline, and is connected to the water doping manifold, the transparent glass tube is located at the end of the oil gathering manifold and is connected to the oil gathering manifold through a flange.

[0013] The purpose of the present invention can also be achieved by the following technical measures:

[0014] The remote pressure gauge collects wellhead back pressure data in real time and transmits it to the mobile terminal.

[0015] The remote temperature meter collects temperature data in real time and transmits it to the mobile terminal.

[0016] The mass flow meter measures the flow value to adjust the amount of water added.

[0017] The transparent glass tube is used to observe the adhesion of condensed oil to the wall.

[0018] The non-heating oil collection and water mixing optimization system for heavy oil fields also includes a motion camera, which is connected to the transparent glass tube to photograph the oil-water multiphase flow characteristics and the condensed oil wall deposition situation.

[0019] The object of the present invention can also be achieved by the following technical measures: a heavy oil field non-heating oil collection and water mixing optimization method, the heavy oil field non-heating oil collection and water mixing optimization method adopts a heavy oil field non-heating oil collection and water mixing optimization system, comprising:

[0020] Step 1, defining the wall adhesion temperature;

[0021] Step 2, deriving a calculation formula for the thick oil wall deposition temperature, and calculating the wall deposition temperature value T1;

[0022] Step 3, calculating the oil temperature T2 at the end point of the gathering and transportation pipeline;

[0023] Step 4: Determine the size of the wall adhesion temperature T1 and the oil temperature T2 at the end of the pipeline. When T1 is greater than or equal to T2, reversely calculate the lowest starting oil temperature T Rmin ;

[0024] Step 5: Calculate T Rmin Water addition temperature and water addition amount under temperature conditions.

[0025] The purpose of the present invention can also be achieved by the following technical measures:

[0026] In step 1, the heavy oil is collected without heating and cooled naturally, and the point where the wellhead back pressure increases sharply with the oil collection temperature during the oil collection process is found through the remote temperature gauge and the remote pressure gauge, which is defined as the sticky wall accumulation temperature.

[0027] In step 2, the calculation formula for the thick oil wall deposition temperature is derived based on the oil-water two-phase flow characteristics in the unheated gathering and transportation process observed in the transparent glass tube and the pipeline pressure drop variation law obtained from the remote pressure gauge.

[0028] In step 2, the calculation formula for the heavy oil wall deposition temperature is:

[0029]

[0030] Where T1 is the thick oil wall deposition temperature, ℃; T0 is the crude oil solidification point, ℃; φ is the volume water content of crude oil; μ is the mixed viscosity of oil-water two-phase flow, D is the diameter of the pipeline, m; v is the average flow velocity of oil-water two-phase flow, m / s; a, m, n are dimensionless parameters.

[0031] In step 3, the oil temperature T at the starting point of the gathering and transportation pipeline is obtained according to the remote temperature table. R The oil temperature T2 at the end point of the gathering and transportation pipeline is calculated using the Sukhov temperature drop formula based on the parameters of the pipeline length.

[0032] In step 3, the calculation formula for the oil temperature at the end point of the gathering and transportation pipeline is:

[0033]

[0034] Where: T2 is the end temperature of the pipeline, °C; T R is the starting temperature of the pipeline, ℃; K is the total heat transfer coefficient of the pipeline, W / (m 2 ·℃); D is the outer diameter of the pipeline, m; G is the mass flow rate of the oil-water two-phase mixed fluid in the pipe, kg / s; c is the specific heat capacity of the oil-water two-phase mixed fluid in the pipe, J / (kg·℃); T3 is the temperature of the surrounding environment, where the buried pipeline takes the natural ground temperature at the depth of the center of the pipe, ℃.

[0035] In step 4, compare the temperature of sticky-wall sedimentation T1 with the oil temperature T2 at the end of the pipeline. If T1 < T2, a non-heated gathering and transportation pipeline without water injection can be achieved.

[0036] In step 4, when T1 is greater than or equal to T2, use the temperature of sticky-wall sedimentation T1 of heavy oil as the new oil temperature T2' at the end of the pipeline, and inversely calculate the lowest starting oil temperature T of the pipeline using the Sukhov temperature drop formula. Rmin 。

[0037] In step 4, the lowest starting oil temperature T of the pipeline Rmin is calculated by the formula:

[0038]

[0039] In step 5, according to the law of conservation of energy, the energy of the oil-water mixture after water injection should be equal to the sum of the energy of the wellhead produced fluid and the energy of the injected hot water, and calculate the relationship between the water injection temperature and the water injection volume under the condition of temperature T3.

[0040] In step 5, the relationship between the water injection temperature and the water injection volume is:

[0041] cm(T Rmin -T R )=c w m w (T w -T R )+c o m o (T Rmin -T R )

[0042] Where: c is the specific heat capacity of the oil-water mixture after water injection, J / (kg·℃); T R is the starting temperature of the pipeline, ℃; m is the mass of the oil-water mixture after water injection, kg; c w is the specific heat capacity of water, J / (kg·℃); m w is the mass of the injected hot water, kg; T w is the temperature of the injected hot water, ℃; c o is the specific heat capacity of the wellhead produced fluid, J / (kg·℃); m o is the mass of the wellhead produced fluid, kg.

[0043] The system and method for optimizing water addition in non-heated oil gathering in heavy oil fields of the present invention focus on reducing the total amount of water added in heavy oil gathering and transportation and the water addition temperature based on the temperature limit of non-heated gathering and transportation, and solve the problem of high energy consumption in heavy oil gathering and transportation during high water content period. The method for optimizing water addition in non-heated oil gathering in heavy oil fields of the present invention considers the parameter conditions such as sticky wall siltation temperature, ambient temperature, and heavy oil viscosity, and establishes a water addition parameter optimization calculation equation. Compared with the previous adjustment of water addition parameters based on production experience in oil fields, the method provided by the present invention is scientific, can better solve the problem of high energy consumption in heavy oil gathering and transportation, and provides solid theoretical guidance for heavy oil water addition gathering and transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a flow chart of a specific embodiment of the method for optimizing the non-heating oil collection and water mixing in heavy oil fields of the present invention;

[0045] Figure 2 It is a process flow chart of optimizing the non-heating oil collection and water mixing of heavy oil fields in a specific embodiment of the present invention;

[0046] Figure 3 It is a definition diagram of wall sticking accumulation temperature in a specific embodiment of the present invention;

[0047] In the figure, 1-remote pressure gauge 2-remote temperature gauge 3-gate valve 4-mass flow meter 5-end 6-ball valve 7-transparent glass tube 8-motion camera 9-check valve 10-oil collecting manifold 11-water mixing manifold 12-single well water mixing pipeline 13-single well oil return pipeline. DETAILED DESCRIPTION

[0048] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0050] Figure 1 The present invention is a flow chart of the method for optimizing the water-mixing of non-heated oil collecting in heavy oil fields.

[0051] Step 1: Establish an experimental process that can monitor the oil collection pressure and temperature data and observe the wall adhesion and siltation.

[0052] Step 2: Carry out unheated gathering and natural temperature reduction of heavy oil. Due to the increase in crude oil viscosity and other reasons after the temperature decreases, the pressure drop in the gathering pipeline will generally show two stages: slow fluctuating rise and sharp rise. Find the point where the wellhead back pressure changes from fluctuating rise to sharp increase with the change of gathering temperature during the gathering process, and define it as the wall sticking and siltation temperature, as Figure 3 shown.

[0053] Step 3: According to the flow characteristics of oil-water two-phase flow and the variation law of pipeline pressure drop during unheated gathering and transportation, derive the calculation formula for the wall sticking and siltation temperature of heavy oil, and obtain the wall sticking and siltation temperature value T1;

[0054] Step 4: According to parameters such as the starting oil temperature T R and pipe length of the gathering and transportation pipeline, use the Sukhov temperature drop formula to calculate the ending oil temperature T2 of the gathering and transportation pipeline;

[0055] Step 5: Judge the magnitude relationship between the wall sticking and siltation temperature T1 and the ending oil temperature T2 of the pipeline. If T1 < T2, unheated gathering and transportation under the condition of not adding water can be achieved; otherwise, use the wall sticking and siltation temperature T1 of heavy oil as the new ending oil temperature T’2 of the pipeline, and use the Sukhov temperature drop formula to back-calculate the lowest starting oil temperature T Rmin ;

[0056] Step 6: According to the law of conservation of energy, calculate the water injection temperature and water injection volume under the temperature condition of T Rmin to make the heavy oil gathering pipeline meet the safe gathering and transportation under the condition of the best water injection parameters.

[0057] In Step 3, the formula for the wall sticking and siltation temperature of heavy oil is:

[0058]

[0059] In the formula, T1 is the wall sticking and siltation temperature of heavy oil, °C; T0 is the pour point of crude oil, °C; φ is the volume water content of crude oil; μ is the mixed viscosity of oil-water two-phase flow, D is the diameter of the pipeline, m; v is the average flow velocity of oil-water two-phase flow, m / s; a, m, n are dimensionless parameters.

[0060] In Step 4, the calculation formula for the ending oil temperature of the gathering and transportation pipeline is:

[0061]

[0062] In the formula: T2 is the pipeline ending temperature, °C; T R is the pipeline starting temperature, °C; K is the total heat transfer coefficient of the pipeline, W / (m 2 ·°C); D is the outer diameter of the pipeline, m; G is the mass flow rate of the oil-water two-phase mixed fluid in the pipeline, kg / s; c is the specific heat capacity of the oil-water two-phase mixed fluid in the pipeline, J / (kg·°C); T3 is the temperature of the surrounding environment, and for buried pipelines, the natural ground temperature at the center of the pipeline burial depth is taken, °C.

[0063] In step 5, the formula for calculating the lowest starting oil temperature of the gathering and transportation pipeline is:

[0064]

[0065] In step 6, the relationship between the water addition temperature and the water addition amount is:

[0066] cm(T Rmin -T R )=c w m w (T w -T R )+c o m o (T Rmin -T R )

[0067] Where: c is the mixed specific heat capacity of the oil-water mixed infusion after adding water, J / (kg·℃); m is the mass of the oil-water mixed infusion after adding water, kg; c w is the specific heat capacity of water, J / (kg·℃); m w is the mass of hot water added, kg; T w is the temperature of the hot water added, ℃; c o is the specific heat capacity of the wellhead produced fluid, J / (kg·℃); m o is the mass of the produced fluid at the wellhead, kg.

[0068] The following are several specific embodiments of the present invention.

[0069] Example 1

[0070] In a specific embodiment 1 of the present invention, Figure 2 As shown, the unheated oil gathering and water blending optimization system for heavy oil fields includes a remote pressure gauge 1, a remote temperature gauge 2, a gate valve 3, a mass flow meter 4, a head 5, a ball valve 6, a transparent glass tube 7, a motion camera 8, a check valve 9, an oil gathering manifold 10, a water blending manifold 11, a single well water blending pipeline 12, and a single well oil return pipeline 13.

[0071] Remote pressure gauge 1: collects wellhead back pressure data in real time and transmits it to the mobile terminal.

[0072] Remote temperature meter 2: collect temperature data in real time and transmit it to the mobile terminal.

[0073] Gate valve 3: Control the opening, closing and smoothness of the process.

[0074] Mass flow meter 4: Adjust the amount of water added by observing the mass flow meter value.

[0075] Header 5: Cut off the process.

[0076] Ball valve 6: controls the opening, closing and smoothness of the process.

[0077] Transparent glass tube 7: observe the condensed oil sticking to the wall.

[0078] Motion camera 8: captures the oil-water multiphase flow characteristics and the accumulation of condensed oil on the wall.

[0079] Check valve 9: Control the opening and closing of the process and prevent fluid backflow.

[0080] Oil gathering manifold 10: collects the fluid from the wellhead and transports it to the next process.

[0081] Water mixing manifold 11: provides water mixing for the metering room.

[0082] Single well water injection pipeline 12: provides single well oil collection water injection.

[0083] Single well oil return pipeline 13: collects single well produced fluid. In this embodiment, the component connection method is:

[0084] 1. The remote pressure gauge 1, the remote temperature gauge 2, the gate valve 3, the mass flow meter 4, the ball valve 6, the check valve 9, and the transparent glass tube 7 are connected to the pipeline at the location through flanges.

[0085] 2. The end cap and the manifold are welded, and the single well oil return pipeline 13 is connected to the remote temperature gauge 2 and the gate valve 3 through flanges, and then connected to the oil collecting manifold 10 through welding. The single well water injection pipeline 12 is connected to the gate valve 3 and the mass flow meter 4 through flanges, and then connected to the water injection manifold 11 through welding.

[0086] Experimental system workflow:

[0087] During the normal water-blending and gathering process, the produced fluid from the wellhead is mixed with the water from the water-blending pipeline after passing through the check valve, and then enters the oil gathering manifold through the single well return oil pipeline to complete the entire oil gathering process from the wellhead to the metering room. The heavy oil non-heating gathering and transportation experimental system is modified on the original oil gathering process so that the produced fluid from the wellhead will not be mixed with the hot water in the water-blending pipeline after passing through the check valve, and will return to the oil gathering manifold through a visual pipeline system composed of a transparent glass tube, a ball valve, and a motion camera installed at the end of the oil gathering pipeline. During this period, a motion camera is used to record the oil-water multiphase flow characteristics in the pipeline.

[0088] Example 2

[0089] In a specific embodiment 2 of the present invention, the method for optimizing the non-heated oil collection and water mixing in a heavy oil field comprises the following steps:

[0090] Step 1: Build a heavy oil gathering and transportation experimental system without heating.

[0091] Step 2: Carry out unheated gathering and natural cooling of heavy oil by shutting down the water blending system, and find the point where the wellhead backpressure increases sharply with the change of gathering temperature during the gathering process by combining the remote temperature gauge 2 installed at the front end of the gathering header 10 and the remote pressure gauge 1 installed on the single-well return pipeline 13 for measuring the wellhead backpressure, which is defined as the wall sticking and siltation temperature T1.

[0092] Step 3: According to the change law of the flow characteristics of the oil-water two-phase flow during unheated gathering and transportation observed in the transparent glass tube 7 and the change law of the wellhead backpressure value on the remote pressure gauge 1 installed on the single-well return pipeline 13, derive the calculation formula for the wall sticking and siltation temperature of heavy oil. The calculation formula for the wall sticking and siltation temperature of heavy oil is:

[0093]

[0094] In the formula, T1 is the wall sticking and siltation temperature of heavy oil, °C; T0 is the pour point of crude oil, °C; φ is the volume water content of crude oil; μ is the mixed viscosity of the oil-water two-phase flow, D is the diameter of the pipeline, m; v is the average flow velocity of the oil-water two-phase flow, m / s; a, m, n are dimensionless parameters.

[0095] Step 4: According to the parameters such as the starting oil temperature T R of the gathering pipeline and the pipe length on the remote temperature gauge 2 installed on the single-well return pipeline 13, use the Sukhov temperature drop formula to calculate the ending oil temperature T2 of the gathering pipeline. The calculation formula for the ending oil temperature at the end of the gathering pipeline is:

[0096]

[0097] In the formula: T2 is the pipeline ending temperature, °C; T R is the pipeline starting temperature, °C; K is the total heat transfer coefficient of the pipeline, W / (m 2 · °C); D is the outer diameter of the pipeline, m; G is the mass flow rate of the oil-water two-phase mixed fluid in the pipe, kg / s; c is the specific heat capacity of the oil-water two-phase mixed fluid in the pipe, J / (kg·°C); T3 is the temperature of the surrounding environment, and for buried pipelines, the natural ground temperature at the center of the pipe burial depth is taken, °C.

[0098] Step 5: Judge the magnitude relationship between the wall sticking and siltation temperature T1 and the pipeline ending oil temperature T2. If T1 < T2, unheated gathering and transportation of the gathering pipeline can be realized without water blending. Otherwise, use the wall sticking and siltation temperature T1 of heavy oil as the new pipeline ending oil temperature T2' and inversely calculate the lowest starting oil temperature T Rmin of the pipeline by using the Sukhov temperature drop formula. The calculation formula for the lowest starting oil temperature is:

[0099]

[0100] Step 6: According to the law of conservation of energy, the energy of the oil-water mixed infusion after water addition should be equal to the sum of the energy of the wellhead output fluid and the energy of the hot water. The relationship between the water addition temperature and the water addition amount under the temperature condition of T3 is calculated as follows:

[0101] cm(T Rmin -T R )=c w m w (T w -T R )+c o m o (T Rmin -T R )

[0102] Where: c is the specific heat capacity of the oil-water mixed infusion after adding water, J / (kg·℃); m is the mass of the oil-water mixed infusion after adding water, kg; c w is the specific heat capacity of water, J / (kg·℃); m w is the mass of hot water added, kg; T w is the temperature of the hot water added, ℃; c o is the specific heat capacity of the wellhead produced fluid, J / (kg·℃); m o is the mass of the produced fluid at the wellhead, kg.

[0103] Example 3

[0104] In a specific embodiment 3 of the present invention, the present invention is used to conduct an optimization research experiment of water mixing without heating oil collection in oil field A to test the feasibility and scientificity of the invention. The experiment selected 24 oil wells for water mixing and gathering in oil field A, and operated them for four days according to the optimal water mixing parameters calculated by the present invention. During the operation, the operating data such as oil return temperature and wellhead back pressure were collected to ensure the safe operation of the oil collection system.

[0105] Table 1 Comparison of water injection volume before and after optimization of water injection parameters in experimental oil wells

[0106]

[0107]

[0108] By comparing the energy consumption of water injection before and after the test, it was found that after the test, 366.24 m^3 / d of water injection could be saved in only 24 heavy oil wells, reducing water injection by 71.1%.

[0109] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0110] Except for the technical features described in the specification, all other technical features are known technologies to those skilled in the art.

Claims

1. Optimization system of non-heating oil collection and water mixing in heavy oil fields, It is characterized in that The non-heating oil gathering and water injection optimization system for heavy oil fields comprises a remote pressure gauge, a remote temperature gauge, a gate valve, a single-well oil return pipeline, a transparent glass tube, an oil gathering manifold, a mass flow meter, a water injection manifold and a single-well water injection pipeline. The remote pressure gauge, the remote temperature gauge and the gate valve are connected in sequence and then connected to the single-well oil return pipeline, the single-well oil return pipeline is connected to the oil gathering manifold, the mass flow meter is connected to the gate valve through the single-well water injection pipeline, and is connected to the water injection manifold, and the transparent glass tube is located at the end of the oil gathering manifold.

2. The non-heating oil collection and water mixing optimization system for heavy oil fields according to claim 1, It is characterized in that The remote pressure gauge collects wellhead back pressure data in real time and transmits it to the mobile terminal.

3. The non-heating oil collection and water mixing optimization system for heavy oil fields according to claim 1, It is characterized in that The remote temperature meter collects temperature data in real time and transmits it to the mobile terminal.

4. The non-heating oil collection and water mixing optimization system for heavy oil fields according to claim 1, It is characterized in that The mass flow meter measures the flow value to adjust the amount of water added.

5. The non-heating oil collection and water mixing optimization system for heavy oil fields according to claim 1, It is characterized in that The transparent glass tube is used to observe the adhesion of condensed oil to the wall.

6. The non-heating oil collection and water mixing optimization system for heavy oil fields according to claim 1, It is characterized in that The non-heating oil collection and water mixing optimization system for heavy oil fields also includes a motion camera, which is connected to the transparent glass tube to photograph the oil-water multiphase flow characteristics and the condensed oil wall deposition situation.

7. Optimization method of water mixing in heavy oil field without heating oil collection. It is characterized in that The method for optimizing the non-heating oil collection and water mixing in heavy oil fields adopts the non-heating oil collection and water mixing optimization system in heavy oil fields according to claim 1, comprising: Step 1, defining the wall adhesion temperature; Step 2: derive the calculation formula for the thick oil wall deposition temperature and calculate the wall deposition temperature value T 1 ; Step 3: Calculate the oil temperature T at the end of the gathering and transportation pipeline 2 ; Step 4: Determine the wall adhesion temperature T 1 The oil temperature at the end of the pipeline is T 2 The size of T 1 Greater than or equal to T 2 When the lowest starting oil temperature T of the pipeline is calculated, Rmin ; Step 5: Calculate T Rmin Water addition temperature and water addition amount under temperature conditions.

8. The method for optimizing the non-heated oil collection and water mixing in heavy oil fields according to claim 7, It is characterized in that In step 1, the heavy oil is collected without heating and cooled naturally, and the point where the wellhead back pressure increases sharply with the oil collection temperature during the oil collection process is found through the remote temperature gauge and the remote pressure gauge, which is defined as the sticky wall accumulation temperature.

9. The method for optimizing the non-heated oil collection and water mixing in heavy oil fields according to claim 7, It is characterized in that In step 2, the calculation formula for the thick oil wall deposition temperature is derived based on the oil-water two-phase flow characteristics in the unheated gathering and transportation process observed in the transparent glass tube and the pipeline pressure drop variation law obtained from the remote pressure gauge.

10. The method for optimizing the non-heated oil collection and water mixing in heavy oil fields according to claim 9, It is characterized in that In step 2, the calculation formula for the heavy oil wall deposition temperature is: Where T 1 T is the thick oil wall deposition temperature, °C; 0 is the freezing point of crude oil, ℃; φ is the volumetric water content of crude oil; μ is the mixed viscosity of oil-water two-phase flow, D is the diameter of the pipeline, m; v is the average flow velocity of the oil-water two-phase flow, m / s; a, m, n—dimensionless parameters.

11. The method for optimizing the non-heated oil collection and water mixing in heavy oil fields according to claim 7, It is characterized in that In step 3, the oil temperature T at the starting point of the gathering and transportation pipeline is obtained according to the remote temperature table. R , pipe length, and other parameters, and use the Sukhov temperature drop formula to calculate the oil temperature T at the end of the gathering and transportation pipeline. 2 .

12. The method for optimizing the non-heated oil collection and water mixing in heavy oil fields according to claim 11, It is characterized in that In step 3, the calculation formula for the oil temperature at the end point of the gathering and transportation pipeline is: Where: T 2 is the terminal temperature of the pipeline, °C; T R is the starting temperature of the pipeline, ℃; K is the total heat transfer coefficient of the pipeline, W / (m 2 ·℃); D is the outer diameter of the pipe, m; G is the mass flow rate of the oil-water two-phase mixed fluid in the pipe, kg / s; c is the specific heat capacity of the oil-water two-phase mixed fluid in the pipe, J / (kg·℃); T 3 is the temperature of the surrounding environment, where the buried pipeline takes the natural ground temperature at the depth of the center of the pipe, ℃.

13. The method for optimizing the non-heated oil collection and water mixing in heavy oil fields according to claim 7, It is characterized in that In step 4, determine the wall adhesion temperature T 1 The oil temperature at the end of the pipeline is T 2 The size of T 1 <T 2 , it is possible to realize the non-heating gathering and transportation pipeline without water addition.

14. The method for optimizing the non-heated oil collection and water mixing in heavy oil fields according to claim 13, It is characterized in that In step 4, when T 1 Greater than or equal to T 2 When the heavy oil wall deposition temperature T 1 As the new pipeline end point oil temperature T 2 'Use Sukhov temperature drop formula to calculate the lowest starting oil temperature T of the pipeline Rmin .

15. The method for optimizing the non-heated oil collection and water mixing in heavy oil fields according to claim 14, It is characterized in that In step 4, the lowest starting oil temperature of the pipeline is T Rmin The calculation formula is:

16. The method for optimizing the non-heated oil collection and water mixing in heavy oil fields according to claim 7, It is characterized in that In step 5, according to the law of conservation of energy, the energy of the oil-water mixed infusion after adding water should be equal to the sum of the energy of the wellhead output fluid and the energy of the hot water added, and T is calculated. 3 The relationship between water mixing temperature and water mixing amount under temperature conditions.

17. The method for optimizing the non-heated oil collection and water mixing in heavy oil fields according to claim 16, It is characterized in that In step 5, the relationship between the water addition temperature and the water addition amount is: cm(T Rmin -T R )=c w m w (T w -T R )+c o m o (T Rmin -T R ) Where: c is the specific heat capacity of the oil-water mixed infusion after adding water, J / (kg·℃); T R is the starting temperature of the pipeline, ℃; m is the mass of the oil-water mixed liquid after adding water, kg; c w is the specific heat capacity of water, J / (kg·℃); m w is the mass of hot water added, kg; T w is the temperature of the hot water added, ℃; c o is the specific heat capacity of the wellhead produced fluid, J / (kg·℃); m o is the mass of the produced fluid at the wellhead, kg.

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