Oil-water interface monitoring method for heavy oil working condition

Abstract

The invention discloses a method for monitoring an oil-water interface under a heavy oil working condition, which comprises the following steps of: establishing an oil-water interface calculation model in an oil-water separator on the basis of parameters of the oil-water separator, preset water phase density, oil phase density of each section and a compensation coefficient; according to the parameters of the oil-water separator, the distance between the oil-water interface low alarm point and the 0 liquid level of an oil-water mixing cabin of the oil-water separator is obtained; according to the parameters of the oil-water separator, the distance between the oil-water interface low alarm point and the oil-water interface low alarm point is obtained; obtaining the distance between the oil-water interface low alarm point and the oil-water interface set point; obtaining the distance between the oil-water interface set point and the oil-water interface high alarm point; obtaining the distance between the oil-water interface high alarm point and the oil-water interface high alarm point; based on the gravitational acceleration of the position where the oil-water separation device is located, pressure calculation is conducted, and accurate control and accurate measurement of the oil-water interface of the oil-water separator under the heavy oil working condition are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of offshore oil engineering, and in particular relates to an oil-water interface monitoring method in a heavy oil working condition. Background Art

[0002] The offshore platform oil-water separator consists of two compartments, namely the oil tank and the oil-water mixed tank, which are separated by a weir plate. In the oil-water mixed tank, the principle of gravity sedimentation is used. Oil is light and water is heavy. After sufficient sedimentation, the lower layer of the oil-water mixed tank is water and the upper layer is crude oil. The upper layer of crude oil overflows the weir plate and enters the oil tank. In order to ensure the separation effect, the oil-water interface in the oil-water mixed tank needs to be controlled to be lower than the high alarm point of the oil-water interface, and the oil-water interface in the oil-water mixed tank needs to be controlled to be higher than the low alarm point of the oil-water interface.

[0003] Conventional oil-water interface measurement methods are all direct contact measurements, and all have applicable viscosity ranges. For high-viscosity conditions, sticking and hanging of materials are prone to occur, resulting in inaccurate or impossible measurements. At the same time, it is no longer applicable to conditions with high water content in crude oil.

[0004] Therefore, it is urgent to design an oil-water interface monitoring method for heavy oil conditions to solve the problem of oil-water interface monitoring under the heavy oil conditions mentioned above. Summary of the invention

[0005] In order to solve the technical problem mentioned in the background technology that direct contact measurement is prone to jamming and hanging of materials in high viscosity conditions, resulting in inaccurate measurement or inability to measure, a method for monitoring the oil-water interface in heavy oil conditions is provided to solve the problem of oil-water interface monitoring in heavy oil conditions.

[0006] To achieve the above purpose, the specific technical scheme of the oil-water interface monitoring method of heavy oil working conditions of the present invention is as follows: A method for monitoring an oil-water interface in a heavy oil working condition comprises the following steps: S1. Based on the parameters of the oil-water separator, the preset water phase density, the oil phase density of each section, and the compensation coefficient, a calculation model of the oil-water interface in the oil-water separator is established; S2. According to the oil-water separator parameters, the distance of the low-low alarm point of the oil-water interface relative to the zero liquid level of the oil-water mixing tank of the oil-water separator is obtained; S3. According to the oil-water separator parameters, the distance between the low-low alarm point of the oil-water interface and the low alarm point of the oil-water interface is obtained; S4. According to the oil-water separator parameters, the distance between the low alarm point of the oil-water interface and the set point of the oil-water interface is obtained; S5. According to the oil-water separator parameters, the distance between the oil-water interface set point and the oil-water interface high alarm point is obtained; S6. According to the oil-water separator parameters, the distance between the high alarm point of the oil-water interface and the high-high alarm point of the oil-water interface is obtained; S7. Calculate the pressure based on the gravity acceleration at the location of the oil-water separation device; S8. Calculate the pressure based on the preset water phase density, the oil phase density of each section, and the compensation coefficient.

[0007] Further, in S3, based on the relative position between the low-low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator and the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator and the water phase density value, the set pressure of the first differential pressure measuring device is obtained.

[0008] Further, in S4, based on the relative position between the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator and the set point of the oil-water interface in the oil-water mixing tank of the oil-water separator and the water phase density value, the set pressure of the second differential pressure measuring device is obtained.

[0009] Further, in S5, based on the relative position between the oil-water interface set point of the oil-water mixing tank of the oil-water separator and the high alarm point of the oil-water interface of the oil-water mixing tank of the oil-water separator and the water phase density value, the set pressure of the third differential pressure measuring device is obtained.

[0010] Further, in S6, based on the relative position between the high alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator and the high-high alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator and the water phase density value, the set pressure of the fourth differential pressure measuring device is obtained.

[0011] Furthermore, the high-pressure side of the first differential pressure measuring device is installed at the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator to perform the first differential pressure measurement.

[0012] Furthermore, the high-pressure side of the second differential pressure measuring device is installed at the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the set point of the oil-water interface in the oil-water mixing tank of the oil-water separator to perform the second differential pressure measurement.

[0013] Furthermore, the high-pressure side of the third differential pressure measuring device is installed at the oil-water interface set point position of the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the oil-water interface high alarm point position of the oil-water mixing tank of the oil-water separator to perform the third differential pressure measurement.

[0014] Furthermore, the high-pressure side of the fourth differential pressure measuring device is installed at the high alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the high alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator to perform the fourth differential pressure measurement.

[0015] Furthermore, the first differential pressure measuring device, the second differential pressure measuring device, the third differential pressure measuring device and the fourth differential pressure measuring device are all double-flange diaphragm differential pressure measuring sensors.

[0016] The oil-water interface monitoring method for heavy oil working conditions of the present invention has the following advantages: By utilizing the inherent structural characteristics of the oil-water separator, the positions of the first differential pressure measuring device, the second differential pressure measuring device, the third differential pressure measuring device, and the fourth differential pressure measuring device are set in the differential pressure measuring system, and the differential pressure measurement values ​​of the four differential pressure measuring points are used as input. In combination with the positions of the low-low alarm point, the low alarm point, the set point, the high alarm point, and the high-high alarm point of the oil-water interface, the position of the oil-water interface can be obtained, thereby achieving accurate control and accurate measurement of the oil-water interface of the oil-water separator under heavy oil conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The process flow chart of the oil-water interface monitoring method for heavy oil working conditions of the present invention is as follows; Figure 2 It is a system schematic diagram of the oil-water interface monitoring method for heavy oil working conditions of the present invention.

[0018] Description of the markings in the figure: 1. First differential pressure measuring device; 2. Second differential pressure measuring device; 3. Third differential pressure measuring device; 4. Fourth differential pressure measuring device; 5. Oil-water separator; 6. Weir plate. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0020] Those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0021] Please refer to the attached Figure 1 To Attachment Figure 2 The oil-water interface monitoring method for heavy oil working conditions of the present invention is described.

[0022] like Figure 2As shown, the oil-water interface monitoring method for heavy oil working conditions in the present invention includes a differential pressure measurement system and an intelligent processing system; the differential pressure measurement system is installed in the oil-water mixing chamber of the oil-water separator 5; the intelligent processing system is installed near the oil-water separator 5; the oil-water separator 5 includes two compartments, namely the oil tank and the oil-water mixing chamber, and the two compartments are separated by a weir plate 6.

[0023] Based on the position parameters of the oil-water separator 5 such as the low-low alarm point, low alarm point, set point, high alarm point, and high-high alarm point, and based on the preset water phase density, the oil phase density of each section, and the compensation coefficient, the oil-water interface position is dynamically simulated.

[0024] Preferably, the differential pressure measurement system comprises a first differential pressure measurement device 1, a second differential pressure measurement device 2, a third differential pressure measurement device 3 and a fourth differential pressure measurement device 4, and all of them are in the form of double flange diaphragms.

[0025] By utilizing the inherent structural characteristics of the oil-water separator 5, the positions of the first differential pressure measuring device 1, the second differential pressure measuring device 2, the third differential pressure measuring device 3, and the fourth differential pressure measuring device 4 in the differential pressure measuring system are set, and the differential pressure measurement values ​​of the four differential pressure measuring points are used as input. In combination with the low-low alarm point (LL), the low alarm point (L), the set point, the high alarm point (H), and the high-high alarm point position (HH) of the oil-water interface, the position of the oil-water interface can be obtained, thereby achieving accurate control and accurate measurement of the oil-water interface of the oil-water separator 5 under heavy oil conditions.

[0026] Further, if Figure 1 and Figure 2 As shown, in this embodiment, the high-pressure side of the first differential pressure measuring device 1 is installed at the low alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, and the low-pressure side is installed at the low alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, to measure the differential pressure values ​​at two points; the high-pressure side of the second differential pressure measuring device 2 is installed at the low alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, and the low-pressure side is installed at the set point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, to measure the differential pressure values ​​at two points.

[0027] The high-pressure side of the third differential pressure measuring device 3 is installed at the set point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, and the low-pressure side is installed at the high alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, to measure the differential pressure values ​​at two points; the high-pressure side of the fourth differential pressure measuring device 4 is installed at the high alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, and the low-pressure side is installed at the high-high alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, to measure the differential pressure values ​​at two points.

[0028] Further, if Figure 1 and Figure 2As shown, in this embodiment, the setting pressure of the first differential pressure measuring device 1 is consistent with the pressure when the water phase is between the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator 5 and the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator 5; the setting pressure of the second differential pressure measuring device 2 is consistent with the pressure when the water phase is between the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator 5 and the set point of the oil-water interface in the oil-water mixing tank of the oil-water separator 5.

[0029] The setting pressure of the third differential pressure measuring device 3 is consistent with the pressure when the water phase is between the oil-water interface setting point of the oil-water mixing tank of the oil-water separator 5 and the high alarm point of the oil-water interface of the oil-water mixing tank of the oil-water separator 5; the setting pressure of the fourth differential pressure measuring device 4 is consistent with the pressure when the water phase is between the high alarm point of the oil-water interface of the oil-water mixing tank of the oil-water separator 5 and the high-high alarm point of the oil-water interface of the oil-water mixing tank of the oil-water separator 5.

[0030] Preferably, the oil-water interface position is calculated by the differential pressure value, the set value, the relative position of the low-low alarm point and the low alarm point, the relative position of the low alarm point and the set point, the relative position of the set point and the high alarm point, and the relative position of the high alarm point and the high-high alarm point.

[0031] The present application provides a method for monitoring the oil-water interface in a heavy oil working condition, which mainly comprises the following steps: S1. The high-pressure side of the first differential pressure measuring device 1 is installed at the low alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, and the low-pressure side is installed at the low alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5; the high-pressure side of the second differential pressure measuring device 2 is installed at the low alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, and the low-pressure side is installed at the set point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5; the high-pressure side of the third differential pressure measuring device 3 is installed at the set point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, and the low-pressure side is installed at the high alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5; the high-pressure side of the fourth differential pressure measuring device 4 is installed at the high alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5, and the low-pressure side is installed at the high alarm point position of the oil-water interface in the oil-water mixing tank of the oil-water separator 5.

[0032] Preset water phase density , density of oil phase in each section , , , compensation coefficient , , , .

[0033] S2. According to the oil-water separator parameters, the distance between the low alarm point of the oil-water interface and the liquid level of the oil-water mixing tank 0 of the oil-water separator 5 is obtained. ; S3. According to the oil-water separator parameters, the distance between the low alarm point of the oil-water interface and the low alarm point of the oil-water interface is obtained. ; S4. According to the oil-water separator parameters, the distance between the low alarm point of the oil-water interface and the set point of the oil-water interface is obtained. ; S5. According to the oil-water separator parameters, the distance between the oil-water interface set point and the oil-water interface high alarm point is obtained. ; S6. According to the oil-water separator parameters, the distance between the high alarm point of the oil-water interface and the high alarm point of the oil-water interface is obtained. ; S7, the gravity acceleration g at the location of the oil-water separation device, or the gravity acceleration obtained from the manufacturer, to calculate the pressure; S8. Preset water phase density, oil phase density of each section, and compensation coefficient to calculate pressure; S9, the relative position between the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator 5 and the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator 2 and the water phase density value, and the set pressure of the first differential pressure measuring device 1 is obtained. ; S10, the relative position between the low alarm point of the oil-water interface of the oil-water mixing tank of the oil-water separator 5 and the set point of the oil-water interface of the oil-water mixing tank of the oil-water separator 5 and the water phase density value, and the set pressure of the second differential pressure measuring device 2 is obtained ; S11, the relative position between the oil-water interface setting point of the oil-water mixing tank of the oil-water separator 5 and the high alarm point of the oil-water interface of the oil-water mixing tank of the oil-water separator 5 and the water phase density value, and the setting pressure of the third differential pressure measuring device 3 is obtained. ; S12, the relative position between the high alarm point of the oil-water interface of the oil-water mixing tank of the oil-water separator 5 and the high alarm point of the oil-water interface of the oil-water mixing tank of the oil-water separator 5 and the water phase density value, and the set pressure of the fourth differential pressure measuring device 4 is obtained. ; S13, the high-pressure side is installed at the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator 5 to measure the first differential pressure ∆ Measurement; S14, the high-pressure side is installed at the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the oil-water interface setting point of the oil-water mixing tank of the oil-water separator 5 to measure the second differential pressure ∆ Measurement; S15, the high-pressure side is installed at the oil-water interface setting point position of the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the oil-water interface high alarm point position of the oil-water mixing tank of the oil-water separator 5 to measure the third differential pressure ∆ Measurement; S16, the high-pressure side is installed at the high alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the high alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator 5 to measure the fourth differential pressure ∆ Measurement; S17, comparing the measured differential pressure value with the set value to determine the interval where the oil-water interface is located; S18, the measured differential pressure of the whole water section and the relative position of this section, and the water phase density , while replacing the preset water phase density; In S19 and S17, the interval where the oil-water interface is located is determined, and the density of the oil phase in the previous section is obtained based on the measured differential pressure value and relative position of the previous section; the position of the oil-water interface is obtained based on the differential pressure value of this section and the density of the oil phase in the previous section; at the same time, when the oil-water interface just enters this section, the compensation coefficient of the previous section can be obtained; In S20 and S19, the compensation coefficient of this section is obtained and then assigned to the compensation coefficient of this section; In S21 and S20, the compensation coefficients of this section are obtained, and then the average is assigned to the compensation coefficient of this section. Then the next round of oil-water interface judgment is carried out.

[0034] Furthermore, if the oil-water interface does not reach the first section, the output is normal and the water phase density value is recorded at the same time. ; If the oil-water interface has reached the first section, record the compensation coefficient at the moment of arrival , output and record , output low alarm, and simulate the oil-water interface position and output it.

[0035] If the oil-water interface has not reached the second section, the output is normal; if the oil-water interface has reached the second section, the compensation coefficient at the moment of arrival is recorded. , output and record , and at the same time simulate the oil-water interface position and output it.

[0036] If the oil-water interface has not reached the third section, a high alarm is output; if the oil-water interface has reached the third section, the output is normal and the compensation coefficient at the moment of arrival is recorded. , output and record , and at the same time simulate the oil-water interface position and output it.

[0037] If the oil-water interface has not reached the fourth section, a high-high alarm is output; if the oil-water interface has reached the fourth section, a high alarm is output, and the oil-water interface position is simulated and output.

[0038] The oil-water interface monitoring method based on heavy oil working conditions uses a flange diaphragm pressure sensor for measurement. By adopting an isolation diaphragm, crude oil and dirty media are prevented from entering the instrument for measurement, and direct contact with crude oil is avoided. Even if the isolation diaphragm is stained with crude oil, it will not affect the transmission of pressure, which effectively solves the technical problem of inaccurate or unmeasuring the oil-water interface of the oil-water separator 5 under heavy oil working conditions; crude oil is not used as an accurate measurement input condition, and high-precision measurement is achieved; it is safe, reliable, economical and applicable, and provides a strong guarantee for timely and accurate monitoring of the oil-water interface position in the oil-water separator 5 under super-heavy oil working conditions.

[0039] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for monitoring the oil-water interface in heavy oil working conditions, characterized in that: The following steps are involved: S1. Based on the parameters of the oil-water separator, the preset water phase density, the oil phase density of each section, and the compensation coefficient, a calculation model of the oil-water interface in the oil-water separator is established; S2. According to the oil-water separator parameters, the distance of the low-low alarm point of the oil-water interface relative to the zero liquid level of the oil-water mixing tank of the oil-water separator is obtained; S3. According to the oil-water separator parameters, the distance between the low-low alarm point of the oil-water interface and the low alarm point of the oil-water interface is obtained; S4. According to the oil-water separator parameters, the distance between the low alarm point of the oil-water interface and the set point of the oil-water interface is obtained; S5. According to the oil-water separator parameters, the distance between the oil-water interface set point and the oil-water interface high alarm point is obtained; S6. According to the oil-water separator parameters, the distance between the oil-water interface high alarm point and the oil-water interface high-high alarm point is obtained; S7. Calculate the pressure based on the gravity acceleration at the location of the oil-water separation device; S8. Calculate the pressure based on the preset water phase density, the density of each oil phase, and the compensation coefficient.

2. The oil-water interface monitoring method for heavy oil working conditions according to claim 1, characterized in that: In S3, based on the relative position between the low-low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator and the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator and the water phase density value, the set pressure of the first differential pressure measuring device is obtained.

3. The oil-water interface monitoring method for heavy oil working conditions according to claim 1, characterized in that: In S4, based on the relative position between the low alarm point of the oil-water interface of the oil-water mixing tank of the oil-water separator and the set point of the oil-water interface of the oil-water mixing tank of the oil-water separator and the water phase density value, the set pressure of the second differential pressure measuring device is obtained.

4. The oil-water interface monitoring method for heavy oil working conditions according to claim 1, characterized in that: In S5, based on the relative position between the oil-water interface set point of the oil-water mixing tank of the oil-water separator and the high alarm point of the oil-water interface of the oil-water mixing tank of the oil-water separator and the water phase density value, the set pressure of the third differential pressure measuring device is obtained.

5. The oil-water interface monitoring method for heavy oil working conditions according to claim 1, characterized in that: In S6, based on the relative position between the high alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator and the high-high alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator and the water phase density value, the set pressure of the fourth differential pressure measuring device is obtained.

6. The oil-water interface monitoring method for heavy oil working conditions according to claim 2, characterized in that: The high-pressure side of the first differential pressure measuring device is installed at the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator to perform the first differential pressure measurement.

7. The oil-water interface monitoring method for heavy oil working conditions according to claim 3 is characterized in that: The high-pressure side of the second differential pressure measuring device is installed at the low alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the set point of the oil-water interface in the oil-water mixing tank of the oil-water separator to perform the second differential pressure measurement.

8. The oil-water interface monitoring method for heavy oil working conditions according to claim 4, characterized in that: The high-pressure side of the third differential pressure measuring device is installed at the oil-water interface set point position of the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the oil-water interface high alarm point position of the oil-water mixing tank of the oil-water separator to perform the third differential pressure measurement.

9. The oil-water interface monitoring method for heavy oil working conditions according to claim 5, characterized in that: The high-pressure side of the fourth differential pressure measuring device is installed at the high alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator, and the low-pressure side is installed at the high-high alarm point of the oil-water interface in the oil-water mixing tank of the oil-water separator to perform the fourth differential pressure measurement.

10. The oil-water interface monitoring method for heavy oil working conditions according to claims 1-5, characterized in that: The first differential pressure measuring device, the second differential pressure measuring device, the third differential pressure measuring device and the fourth differential pressure measuring device are all double-flange diaphragm differential pressure measuring sensors.

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