Oilfield blending system

Abstract

The present invention relates to the technical field of oil fields, and discloses an oil field blending system, including: a water blending pipeline, an oil return pipeline, and an operation control unit; the water blending pipeline is connected to an oil well; the water blending pipeline is connected with a universal regulating valve for adjusting the water blending flow rate and a multi-parameter detector for detecting the water blending temperature, water blending pressure, and water blending flow rate; the oil return pipeline is connected to the oil well; the oil return pipeline is connected with an oil return temperature sensor; the universal regulating valve, the multi-parameter detector, and the oil return temperature sensor are all connected to the operation control unit; the operation control unit adjusts the universal regulating valve according to the data fed back by the multi-parameter detector and the oil return temperature sensor. The blending system in the present invention can realize precise control of the temperature at the end of the delivery pipeline.

Description

Technical Field

[0001] The present invention relates to the technical field of oil fields, and more particularly to an oil field blending system. Background Art

[0002] Appropriate temperature control is required during the transportation of crude oil, with the focus on controlling the temperature at the end of the pipeline. Otherwise, serious consequences will occur, affecting the transportation of crude oil, thereby significantly increasing the subsequent maintenance and repair costs.

[0003] At present, the operator controls the water flow rate by adjusting the opening of the manual valve of the hot water pipeline, and then indirectly controls the temperature at the end of the pipeline. This manual adjustment method is not accurate in controlling the temperature at the end of the pipeline. When the temperature at the end of the pipeline is too high, it is easy to corrode the pipeline and scale, and cause energy waste; when the temperature at the end of the pipeline is too low, the pipeline will wax, and in severe cases, the pipeline will completely freeze, making it impossible to transport crude oil.

[0004] Experiments to accurately control the terminal temperature have been ongoing so far, but the reason for the failure is that the blending system is a long-delay regulation system. It takes about 2 hours from the action of the regulating valve to the terminal temperature response (related to the length of the oil pipeline and the fluid flow rate). Ordinary PID regulation will cause oscillation.

[0005] Therefore, developing an oilfield blending system that can accurately control the temperature at the end of the delivery pipeline is an urgent problem that those skilled in the art need to solve. Summary of the invention

[0006] In view of this, the present invention provides an oilfield blending system which can accurately control the temperature at the end of a transmission pipeline.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] An oilfield blending system, comprising:

[0009] A water injection pipeline, the water injection pipeline is connected to the oil well; the water injection pipeline is connected with a universal regulating valve for adjusting the water injection flow rate and a multi-parameter detector for detecting the water injection temperature, water injection pressure and water injection flow rate;

[0010] An oil return pipeline, the oil return pipeline is connected to the oil well; the oil return pipeline is connected to an oil return temperature sensor;

[0011] An operation control unit, the universal regulating valve, the multi-parameter detector, and the return oil temperature sensor are all connected to the operation control unit; the operation control unit adjusts the universal regulating valve according to the data fed back by the multi-parameter detector and the return oil temperature sensor.

[0012] The beneficial effect of adopting the above technical solution is that the present invention controls the flow rate of water injection by detecting the return oil temperature close to the wellhead, thereby eliminating the long delay and serious reaction lag problems of the existing injection system, thereby effectively improving the accuracy of temperature control at the end of the oil main pipeline.

[0013] Preferably, at the moment when the hot water in the water mixing pipeline mixes with the crude oil in the oil well, according to the law of conservation of energy, the heat released by the hot water is equal to the heat absorbed by the crude oil, that is, , calculated ;in is the flow rate of hot water in the water mixing pipeline; is the flow rate of crude oil in the oil well; is the specific volume of crude oil in the oil well; is the specific volume of hot water in the water mixing pipeline; is the temperature of hot water in the water mixing pipeline; is the temperature of crude oil in the oil well; is the target temperature after the crude oil and hot water are mixed; through the above conversion, the control of the target temperature after mixing is converted into the control of the hot water flow in the water mixing pipeline.

[0014] Preferably, the flow rate of hot water in the water mixing pipeline is ; is the flow coefficient of the universal control valve; is the pressure difference before and after the universal regulating valve; the characteristic curve of the universal regulating valve is B; x is the opening of the universal regulating valve; B is the adjustable ratio; where = · = B · ;although As the opening increases, it decreases, but due to The increase is much higher than The decrease ensures the accuracy requirements at small openings and the controllable range requirements at large openings.

[0015] Preferably, the value of the adjustable ratio B is greater than 500.

[0016] Preferably, the water mixing pipeline is connected to the water main. The water main can be connected to multiple water mixing pipelines, which is convenient for connecting multiple oil wells and forming multiple groups of mixing and delivery systems in parallel.

[0017] Preferably, the oil return pipeline is connected to the oil main pipeline.

[0018] Preferably, a terminal temperature sensor is provided at the end of the oil main pipe, and the terminal temperature sensor is connected to the operation control unit to feed back the detected temperature signal to the operation control unit. Since the oil is transmitted from the return oil port to the end of the oil main pipe over a long distance, there are many factors affecting the temperature. In the present invention, the water mixing flow rate is adjusted by detecting the temperature at the return oil port. At the same time, the operation control unit can also appropriately adjust and correct the parameters through the temperature feedback at the end of the oil main pipe.

[0019] Preferably, the oil return pipeline is connected to a three-way valve, one end of the three-way valve is directly connected to the oil main pipe, and the other end is connected to the oil main pipe after passing through a metering hopper.

[0020] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses an oilfield blending system, which has the following beneficial effects:

[0021] (1) The blending system of the present invention realizes precise control of the terminal temperature by controlling the front-end flow ratio and using the terminal temperature feedback as a correction;

[0022] (2) The blending system can achieve precise control of the terminal temperature and unmanned on-site management, greatly reducing safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0024] Figure 1 A schematic diagram of the structure of the doping system provided by the present invention;

[0025] Figure 2 This is a diagram showing the operation principle of the doping system provided by the present invention.

[0026] Among them, in the figure,

[0027] 1-water mixing pipeline; 2-oil well; 3-universal regulating valve; 4-multi-parameter detector; 5-return oil pipeline; 6-return oil temperature sensor; 7-water main pipe; 8-oil main pipe; 9-terminal temperature sensor; 10-three-way valve; 11-metering hopper. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] like Figure 1-2 As shown, an embodiment of the present invention discloses an oilfield blending system, comprising:

[0030] A water injection pipeline 1 is connected to an oil well 2; the water injection pipeline 1 is connected with a universal regulating valve 3 for adjusting the flow rate of water injection and a multi-parameter detector 4 for detecting the temperature, pressure and flow rate of water injection;

[0031] An oil return pipeline 5, the oil return pipeline 5 is connected to the oil well 2; an oil return temperature sensor 6 is connected to the oil return pipeline 5;

[0032] The operation control unit, the universal regulating valve 3, the multi-parameter detector 4, and the return oil temperature sensor 6 are all connected to the operation control unit; the operation control unit adjusts the universal regulating valve 3 after performing operations based on the data fed back by the multi-parameter detector 4 and the return oil temperature sensor 6.

[0033] In order to further optimize the above technical solution, the multi-parameter detector 4 measures the water injection pressure and can monitor the water injection pressure in real time. If the water injection pressure is abnormal, it means that a fault has occurred, which serves as a warning. Similarly, if the actual value of the temperature at the end of the oil main pipe 8 is significantly different from the measured value, it means that there is an oil leak.

[0034] In order to further optimize the above technical solution, since the distance from the oil return port to the end is long, the method of adjusting the universal regulating valve 3 according to the temperature at the end of the oil main pipe 8 will have a long delay and serious reaction lag. In the present invention, the universal regulating valve 3 is adjusted according to the temperature at the front end of the oil return pipeline 5, which can respond quickly and achieve adjustment; in order to accurately control the terminal temperature, it is necessary to estimate the temperature drop caused by the distance from the oil return port to the end. Because the temperature drop of this part is proportional to the length of the pipeline, the diameter of the pipeline, the thermal conductivity of the pipeline insulation material, the temperature difference between the mixed liquid temperature and the ambient temperature, and the flow rate of the mixed liquid. Among the above factors, one and two have been determined when the pipeline is designed, three will deteriorate more and more over time, and four and five are real-time monitoring data.

[0035] In practice, by feeding back the temperature at the end of the oil main pipe 8 to the calculation control unit, the difference between the temperature of the return oil pipeline 5 and the temperature at the end of the oil main pipe 8 can be obtained. , produced , , The corresponding relationship table, where is the impact of environmental factors on temperature, is the flow rate after the crude oil and hot water are mixed; when making the corresponding relationship table, the effective table length is taken as n, and the corresponding relationship table is as follows:

[0036] ( ; ; ; ; ; ; ;......; )

[0037] ( ; ; ; ; ; ; ;......; ;)

[0038] ( ; ; ; ; ; ; ;......; ;)

[0039] When new data is entered, an existing data is removed; assuming and , All are linear relationships, so the temperature drop equation is obtained: ,in, is the contribution coefficient of ambient temperature to temperature drop, is the contribution coefficient of flow rate to temperature drop after crude oil and hot water are mixed.

[0040] make is the error between the i-th group of data and the temperature drop equation, then ;Pick ;but

[0041] In order to minimize the error between the fitted function and the data in the table, let , , ; then the system of equations:

[0042]

[0043] The above equation can be solved using the array in the corresponding relationship table For these three coefficients, we only need to know the ambient temperature and the mixed flow rate to calculate the pipeline temperature drop. If the return oil temperature is controlled to an ideal state, the sum of the temperature at the end of the oil main pipe 8 and the pipeline temperature drop can achieve the purpose of accurately controlling the temperature at the end of the oil main pipe 8. When environmental factors change, the temperature drop can be quickly obtained by applying the above formula, thereby obtaining the target value of the return oil temperature. According to the feedback of the temperature at the end of the oil main pipe 8, appropriate correction tables are made. The fuller the data, the more accurate the empirical formula. Through the dual feedback of the temperature at the front end of the return oil pipeline 5 and the end of the oil main pipe 8, if the error between the measured terminal temperature and the calculated temperature is too large, and the water mixing pressure drops seriously, it can be judged that there is oil leakage in the pipeline; if the error between the measured terminal temperature and the calculated temperature is too large, but the water mixing pressure does not drop significantly, it can be concluded that the thermal conductivity of the insulation layer has deteriorated.

[0044] In order to further optimize the above technical solution, at the moment when the hot water in the water mixing pipeline 1 mixes with the crude oil in the oil well 2, according to the law of conservation of energy, the heat released by the hot water is equal to the heat absorbed by the crude oil, that is, , calculated ;in is the flow rate of hot water in the water mixing pipeline 1; is the flow rate of crude oil in oil well 2; is the specific volume of crude oil in oil well 2; is the specific volume of hot water in the water mixing pipeline 1; is the temperature of hot water in the water mixing pipeline 1; is the temperature of crude oil in oil well 2; is the target temperature after the crude oil and hot water are mixed; through the above conversion, the control of the target temperature after mixing is converted into the control of the hot water flow in the water mixing pipeline 1. Since the water flow control is faster and more accurate, after the above conversion, the terminal temperature can be controlled by controlling the hot water flow in the water mixing pipeline 1. Since the return oil pipeline 5 is short, the return oil temperature is close to the mixing temperature. The temperature drop can be calculated from the empirical formula, so the control of the terminal temperature is converted into the control of the water mixing flow. Since the liquid is incompressible, the flow response time is in milliseconds, which well solves the problem that the long delay control system is prone to oscillation.

[0045] In order to further optimize the above technical solution, the flow rate of hot water in the water mixing pipeline 1 is ; is the flow coefficient of the universal regulating valve 3; is the pressure difference before and after the universal regulating valve 3; the characteristic curve of the universal regulating valve 3 is B; x is the opening of the universal regulating valve 3; B is the adjustable ratio; where = · = B · ; Through this derivation formula, we can see that although As the opening increases, it decreases, but due to The increase is much higher than The decrease ensures the accuracy requirements at small openings and the controllable range requirements at large openings.

[0046] In order to further optimize the above technical solution, according to the formula get ;in is the Laplace function of setting flow rate; is the Laplace function of the actual flow; is the transfer function (open loop); is the feedback function. The proportional, integral and differential constants can be obtained by the root locus method, thus obtaining a temperature control system with fast convergence and no oscillation.

[0047] In order to further optimize the above technical solution, the value of the adjustable ratio B is greater than 500.

[0048] In order to further optimize the above technical solution, the water mixing pipeline 1 is connected to the water main 7.

[0049] In order to further optimize the above technical solution, the oil return pipeline 5 is connected to the oil main pipeline 8.

[0050] In order to further optimize the above technical solution, a terminal temperature sensor 9 is provided at the end of the oil main pipe 8, and the terminal temperature sensor 9 is connected to the operation control unit to feed back the detected temperature signal to the operation control unit.

[0051] In order to further optimize the above technical solution, the return oil pipeline 5 is connected to a three-way valve 10, one end of the three-way valve 10 is directly connected to the oil main pipe 8, and the other end is connected to the oil main pipe 8 through a metering hopper 11. In the working state, the oil enters the oil main pipe 8 after passing through the three-way valve 10. When the oil volume needs to be spot-checked, the oil needs to pass through the metering hopper 11 before entering the oil main pipe 8 after passing through the three-way valve 10.

[0052] In order to further optimize the above technical solution, Figure 2 The crude oil flow is obtained from the work diagram of the oil pump. In order to prevent the work diagram from deviation, a three-way valve 10 is set in the system. Most of the time, the three-way valve is directly connected to the oil main pipe 8. When it is necessary to check the crude oil flow, the three-way valve 10 is switched to pass through the metering hopper 11 and then connected to the oil main pipe 8. The crude oil passes through the metering hopper 11 for crude oil flow spot check, and the work diagram is corrected with the spot check data.

[0053] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0054] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An oilfield blending system, characterized in that: include: A water injection pipeline (1), the water injection pipeline (1) being in communication with an oil well (2); the water injection pipeline (1) being connected with a universal regulating valve (3) for regulating the flow rate of water injection and a multi-parameter detector (4) for detecting the temperature, pressure and flow rate of water injection; the flow rate of hot water in the water injection pipeline (1) K V is the flow coefficient of the universal regulating valve (3); ΔP is the pressure difference before and after the universal regulating valve (3); the characteristic curve of the universal regulating valve (3) is x=[1+ln(K V / K Vmax ) / ln 10] / lgB; x is the opening of the universal regulating valve (3); B is the adjustable ratio; where Although ΔP decreases with increasing opening, due to K V The increase is higher than The decrease ensures the accuracy requirement at small opening and the controllable range requirement at large opening; At the moment when the hot water in the water mixing pipeline (1) mixes with the crude oil in the oil well (2), according to the law of conservation of energy, the heat released by the hot water is equal to the heat absorbed by the crude oil, that is, C 水 q 水 (T 热水 -T 混合 )=C 油 q 油 (T 混合 -T 油 ), calculated where q 水 is the flow rate of hot water in the water mixing pipeline (1); q 油 is the flow rate of crude oil in the oil well (2); C 油 is the specific volume of crude oil in the oil well (2); C 水 is the specific volume of hot water in the water mixing pipeline (1); T 热水 is the temperature of the hot water in the water mixing pipeline (1); T 油 is the temperature of the crude oil in the oil well (2); T 混合 is the target temperature after the crude oil and hot water are mixed; by converting the heat released by the hot water and the heat absorbed by the crude oil according to the law of energy conservation, the control of the target temperature after mixing is converted into the control of the hot water flow rate in the water mixing pipeline (1); An oil return pipeline (5), the oil return pipeline (5) being in communication with the oil well (2); an oil return temperature sensor (6) being connected to the oil return pipeline (5); An operation control unit, the universal regulating valve (3), the multi-parameter detector (4), and the return oil temperature sensor (6) are all connected to the operation control unit; the operation control unit adjusts the universal regulating valve (3) after performing operations based on data fed back by the multi-parameter detector (4) and the return oil temperature sensor (6).

2. The oilfield blending system according to claim 1, characterized in that: The value of the adjustable ratio B is above 500.

3. The oilfield blending system according to claim 1, characterized in that: The water mixing pipeline (1) is connected to the water main (7).

4. The oilfield blending system according to claim 1, characterized in that: The oil return pipeline (5) is connected to the oil delivery main pipeline (8).

5. The oilfield blending system according to claim 4, characterized in that: A terminal temperature sensor (9) is provided at the end of the oil delivery main pipe (8), and the terminal temperature sensor (9) is connected to the operation control unit to feed back the detected temperature signal to the operation control unit.

6. The oilfield blending system according to claim 4, characterized in that: The oil return pipeline (5) is connected to a three-way valve (10), one end of the three-way valve (10) is directly connected to the oil main pipe (8), and the other end is connected to the oil main pipe (8) through a metering hopper (11).

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