On-site water separation and remixing system and method for single well oil extraction system

Abstract

The present invention provides an on-site water separation and back-mixing system and method for a single-well oil extraction system, and belongs to the technical field of single-well crude oil collection. Its technical scheme is as follows: it includes an oil storage tank and a free water tank used in conjunction with the oil storage tank, a connecting pipe is arranged at the bottom of the oil storage tank and the bottom of the free water tank, a drainage valve assembly is arranged on the connecting pipe, and a back-mixing pipe is also arranged between the oil storage tank and the free water tank, and a back-mixing assembly is arranged on the back-mixing pipe. The beneficial effects of the present invention are as follows: the present invention separates a part of free water from the crude oil produced liquid on-site, greatly reducing the water content of the crude oil, and can also reduce the invalid load generated by the crude oil during the heating process, reduce the energy consumption for heating, and alleviate the inventory pressure of the subsequent gathering and transportation station, which can effectively save energy, improve production efficiency, and reduce heating costs.

Description

Technical Field

[0001] The invention relates to the technical field of crude oil single well collection, and in particular to an on-site water separation and remixing system and method for a single well oil extraction system. Background Art

[0002] In recent years, with the rapid growth of crude oil production in my country, the number of oil wells in remote locations has increased. However, due to the lack of a systematic oil pipeline, the produced crude oil cannot be directly transported through the pipeline network. The crude oil produced liquid is usually stored in a pulling oil storage tank first, and then transported by a pulling oil truck after the pulling oil storage tank is full. However, during the transportation process, due to the high viscosity and high wax content of crude oil, heating is generally used to reduce the viscosity of crude oil and enhance its fluidity, thereby reducing the transportation cost and difficulty.

[0003] In addition, most of my country's oil fields have entered the medium-to-high water content period, and the water content in the produced fluid continues to rise. The water content is basically around 70%, and a few high-water-content areas can reach more than 90%. In addition, since the specific heat capacity of water is much greater than that of crude oil, according to the traditional single-well oil tank heating method, a large amount of heat is required to heat the water, resulting in serious waste of heat energy. In addition, the high water content of crude oil also leads to a significant decrease in the effective oil pulling capacity of the oil truck. Summary of the invention

[0004] The purpose of the present invention is to provide an on-site water separation and remixing system for a single well oil extraction system which can not only reduce the water content of crude oil, but also reduce the invalid load generated during the heating process of crude oil and save energy.

[0005] In order to achieve the above-mentioned purpose of the invention, the present invention provides an on-site water distribution and remixing system for a single-well oil pulling system, including an oil storage tank and a free water tank used in conjunction with the oil storage tank, a connecting pipe is arranged between the bottom of the oil storage tank and the bottom of the free water tank, a drain valve assembly is arranged on the connecting pipe, a remixing pipe is also arranged between the oil storage tank and the free water tank, and a remixing assembly is arranged on the remixing pipe.

[0006] From the oil storage tank to the free water tank, the drainage valve assembly includes: manual valve 1, electric valve 1 and manual valve 2 in sequence.

[0007] The back-mixing valve assembly includes an electric valve 2 and a back-mixing pump arranged between the manual valve and the oil storage tank.

[0008] Electric heating pipes evenly distributed in the height direction are transversely arranged on the inner wall of the free water tank.

[0009] A drain valve is arranged at the bottom of the free water tank.

[0010] The oil storage tank is provided with two water content meters, a temperature sensor and a liquid level sensor.

[0011] The free water tank is provided with a plurality of temperature sensors and a liquid level sensor for respectively measuring the highest liquid level and the lowest liquid level of the free water tank.

[0012] A valve operating platform is arranged between the oil storage tank and the free water tank; a sewage valve operating platform is arranged on the side wall of the free water tank; and a guardrail is arranged on the top of the free water tank.

[0013] In order to better achieve the above-mentioned purpose of the invention, the present invention also provides a method for on-site water separation and remixing of a single well oil extraction system, the method comprising:

[0014] Step 1: The crude oil produced from the oil well enters the oil storage tank through the oil inlet hole, and the liquid level of the crude oil in the oil storage tank is measured by the liquid level sensor. When the liquid level reaches the maximum height of the oil storage tank, the high liquid level alarm of the oil storage tank is triggered, and the oil storage of the oil storage tank ends;

[0015] Step 2: The oil storage tank is left to stand to separate oil and water;

[0016] Step 3: Drain the lower layer of the oil storage tank into the free water tank through the connecting pipe. When the liquid level of the free water tank reaches the maximum load height, the high liquid level alarm of the free water tank is triggered, and the valve on the connecting pipe is closed to stop the liquid in the oil storage tank from flowing into the free water tank.

[0017] Step 4: Determine the oil content in the free water tank.

[0018] When the oil content measured by the water content meter is greater than 3000mg / L, valley electricity is used to heat the liquid in the free water tank before oil extraction; the heated liquid in the free water tank is mixed back into the oil storage tank until the liquid temperature in the oil storage tank reaches the oil extraction temperature of 50-65 o At C, the back-blending is finished and oil pulling is carried out;

[0019] When the oil content measured by the water content meter is no more than 3000mg / L, the liquid in the free water tank is directly discharged through the water truck; before pulling the oil, the liquid in the oil storage tank is heated until the temperature of the liquid in the oil storage tank reaches the oil pulling temperature of 50-65 o C, oil pulling is performed;

[0020] Repeat the above steps.

[0021] The beneficial effects of the present invention are as follows: the present invention separates a portion of free water from crude oil production liquid on site, greatly reducing the water content of the crude oil, and can also reduce the invalid load generated during the heating process of the crude oil, reduce the energy consumption for heating, and alleviate the inventory pressure of subsequent gathering and transportation stations, which can effectively save energy, improve production efficiency, and reduce heating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of Example 1 of the present invention.

[0023] Figure 2 Schematic diagram of the distribution of electric heating pipes and sensors in the free water tank in Examples 1 and 2 of the present invention Figure 1 .

[0024] Figure 3 Schematic diagram of the distribution of electric heating pipes and sensors in the free water tank in Examples 1 and 2 of the present invention Figure 2 .

[0025] Figure 4 This is a top view of the distribution of electric heating tubes and sensors in the free water tank in Examples 1 and 2 of the present invention.

[0026] Figure 5 Schematic diagram of the distribution of electric heating pipes and sensors of the oil storage tank in Examples 1 and 4 of the present invention.

[0027] Figure 6 This is a control logic diagram in embodiments 1, 2 and 6 of the present invention.

[0028] Figure 7 This is a top view of the free water tank support in Example 3 of the present invention.

[0029] Figure 8 It is a side view of the free water tank support in Example 3 of the present invention.

[0030] Fig. 9 This is a front view of the free water tank drain valve operating platform in Example 3 of the present invention.

[0031] Fig.10 It is a top view of the free water tank drain valve operating platform in Example 3 of the present invention.

[0032] Fig.11 This is a front view of the top guardrail of the free water tank in Example 3 of the present invention.

[0033] Fig.12 This is a top view of the top guardrail of the free water tank in Example 3 of the present invention.

[0034] Fig.13 This is a front view of the valve operating platform in Example 5 of the present invention.

[0035] Fig.14 This is a top view of the valve operating platform in Example 5 of the present invention.

[0036] Among them, the accompanying drawings are marked as follows: 1. Oil storage tank guardrail; 2. Oil storage tank bracket; 3. Oil storage tank; 4. Oil inlet valve; 5. Manual valve one; 6. Connecting pipe; 7. Electric valve one; 8. Electric valve two; 9. Back-mixing pump; 10. Manual valve two; 11. Free water tank; 12. Drain valve; 13. Free water tank bracket; 14. Free water tank top guardrail; 15. Valve operating platform support column; 16. Valve operating platform ladder; 17. Valve operating platform bottom plate; 18. Valve operating platform guardrail; 19. Drain valve operating platform guardrail; 20. Drain valve operating platform bottom plate; 21. Drain valve operating platform Ladder; 22. Free water tank ladder; 23. Instrument reserved hole one; 24. Manhole one; 25. Liquid level sensor; 26. Manhole two; 27. Water content meter one; 28. Water content meter two; 29. ​​Instrument reserved hole two; 30, 32, 34, 37, 38, 39 are all electric heating tubes; 31, 33, 35, 40, 41, 42 are all temperature sensors; 36, water outlet pipe; 43, oil inlet hole; 44, observation hole; 45, liquid level sensor; 46, 47 are all temperature sensors; 48, water content meter three; 49, water content meter four; 50, tank internal reinforcement; 51, electric heating tube; 52, oil outlet pipe. DETAILED DESCRIPTION

[0037] In order to clearly illustrate the technical features of this solution, this solution is described below through a specific implementation method.

[0038] Example 1 System

[0039] See also Figure 1 The present invention is an on-site water distribution and remixing system for a single-well oil extraction system, comprising an oil storage tank 3, and also comprising a free water tank 11 used in conjunction with the oil storage tank 3, a connecting pipe 6 is arranged between the bottom of the oil storage tank 3 and the bottom of the free water tank 11, a drainage valve assembly is arranged on the connecting pipe 6, a remixing pipe is also arranged between the oil storage tank 3 and the free water tank 11, and a remixing assembly is arranged on the remixing pipe.

[0040] From the oil storage tank 3 to the free water tank 11, the drainage valve assembly includes: a manual valve 1 5, an electric valve 1 7 and a manual valve 2 10 in sequence.

[0041] The back-mixing valve assembly includes an electric valve 2 8 and a back-mixing pump 9 which are arranged between the manual valve 2 10 and the oil storage tank 3 .

[0042] Electric heating pipes are evenly distributed in the height direction and are transversely arranged on the inner wall of the free water tank 11 .

[0043] A drain valve is provided at the bottom of the free water tank 11 .

[0044] The oil storage tank 3 is provided with two water content meters, a temperature sensor and a liquid level sensor.

[0045] The free water tank 11 is provided with a plurality of temperature sensors and a liquid level sensor for respectively measuring the highest liquid level and the lowest liquid level of the free water tank 11 .

[0046] A valve operating platform is provided between the oil storage tank 3 and the free water tank 11 ; a drain valve operating platform is provided on the side wall of the free water tank 11 ; and a guardrail is provided on the top of the free water tank 11 .

[0047] Example 2 Free Water Tank

[0048] See also Figure 2-4 , based on Example 1, the free water tank 11 is further described.

[0049] The volume V of the free water tank 11 is determined by the volume V0 of the oil pulling tank and the water content α of the oil well, specifically:

[0050] ; 1.2 is the safety factor.

[0051] A liquid level sensor is installed on the top of the free water tank 11 to measure the liquid level of the liquid in the free water tank 11; the free water tank 11 is installed with two water content meters 27 and 28, which are 500mm and 1000mm from the tank top respectively; three layers of electric heating pipes are installed horizontally along the longitudinal direction inside the free water tank 11, with 2 pipes in each layer, and the height difference between two adjacent layers is 300mm-700mm, preferably 500mm, so as to achieve uniform heating of the liquid inside the free water tank 11; the free tank body 11 Six temperature sensors are also installed, three of which are close to the three-layer electric heating pipes for measuring the local temperature near the electric heating pipes and providing high-temperature protection signals for the electric heating pipes. Another three temperature sensors are installed on the inner wall of the free water tank for measuring the liquid temperature in the tank. An instrument reserved hole 23 and an instrument reserved hole 29 are installed on the top of the free water tank 11 to facilitate the addition of other instruments in the future. A manhole 24 and a manhole 26 are installed on the top of the free water tank 11 for subsequent equipment inspection and maintenance.

[0052] Example 3 Auxiliary structure of free water tank

[0053] See also Figure 7-12 On the basis of embodiments 1 and 2, a free water tank bracket 13 is provided at the bottom of the free water tank 11, and the free water tank bracket 13 is set according to the actual size of the free water tank 11. The structure and size of the free water tank bracket 13 provided in this embodiment are as follows: Figure 8 It can be seen that its horizontal cross section is a regular octagon with a side length of 1569mm and a height of 3000mm.

[0054] An operating platform for operating the drain valve 12 is also provided outside the free water tank 11, and the operating platform includes: a drain valve operating platform guardrail 19, a drain valve operating platform bottom plate 20 and a drain valve operating platform ladder 21, wherein the drain valve operating platform guardrail height is 500-1000mm, preferably 800mm.

[0055] A free water tank top guardrail 14 and a free water tank ladder 22 are also provided on the top of the free water tank 11. Similarly, the height of the free water tank top guardrail 14 is 500-1000mm, preferably 800mm.

[0056] Example 4 Oil storage tank

[0057] See also Figure 5 On the basis of the embodiments 1-3, the top of the oil storage tank 3 is provided with a water content meter 1 48 and a water content meter 2 49, which are 500 mm and 1000 mm above the tank top, respectively, a temperature sensor 46, a temperature sensor 47 and a liquid level sensor 45. In addition, the top of the oil storage tank 3 is also provided with an observation hole 44 for observing the situation inside the tank.

[0058] The oil storage tank 3 is provided with internal reinforcement ribs 50 and an electric heating pipe 51 .

[0059] Example 5 Valve operating platform

[0060] See also Figure 13-14 On the basis of Embodiments 1-4, a valve operation platform is provided between the oil storage tank 3 and the free water tank 11, which is convenient for operating the manual valve 1 5 and the manual valve 2 10 to realize the control of the drainage process and the maintenance of the valves. The height of the valve operation platform is equal to the height of the drainage valve operation platform of the free water tank.

[0061] Example 6 Electronic Control

[0062] See also Figure 6 , based on Examples 1-5, all temperature sensors, liquid level sensors, water content meters and electric valves are connected to the PLC ( Figure 6 It is connected to the electronic control cabinet (displayed as "intelligent control cabinet"), controlled by PLC and added with signal remote transmission system; specifically:

[0063] Before the oil pumping system starts, open the oil inlet valve 4, close the manual valve 15, the electric valve 17, the electric valve 28 and the manual valve 210, and pump the crude oil into the oil storage tank 3. The liquid level of the crude oil in the oil storage tank 3 is obtained through the liquid level sensor 45. When the liquid level reaches the maximum height of the oil storage tank 3, the high liquid level alarm of the oil storage tank 3 is triggered, and the PLC controls the pumping unit to stop pumping oil; close the oil inlet valve 4, and let the oil storage tank 3 stand; after standing and stratifying in the oil storage tank 3, first open the manual valve 15 and the manual valve 210, and then open the electric valve 17 to transfer the water at the bottom of the oil storage tank 3 to the free water tank 11. When the liquid level in the free water tank 11 reaches the maximum height measured by the liquid level sensor 25, the high liquid level alarm of the free water tank 11 is triggered, the electric valve 17 is remotely controlled to close, and the manual valve 15 and the manual valve 210 are manually closed to stop the transfer.

[0064] Example 7 Method

[0065] On the basis of Examples 1-6, the present invention further provides a method for in-situ water separation and remixing of a single well oil extraction system, the method comprising:

[0066] Step 1: The crude oil produced from the oil well enters the oil storage tank 3 through the oil inlet hole 43, and the liquid level of the crude oil in the oil storage tank 3 is measured by the liquid level sensor 45. When the liquid level reaches the maximum height that the oil storage tank 3 can bear, the high liquid level alarm of the oil storage tank 3 is triggered, and the oil storage in the oil storage tank 3 ends;

[0067] Step 2: The oil storage tank 3 is left to stand to separate oil and water;

[0068] Step 3: drain the lower layer liquid of the oil storage tank 3 into the free water tank 11 through the connecting pipe 6. When the liquid level of the free water tank 11 reaches the maximum load height, the high liquid level alarm of the free water tank 11 is triggered, and the valve on the connecting pipe is closed to stop the liquid in the oil storage tank 3 from flowing into the free water tank 11.

[0069] Step 4: Determine the oil content in the free water tank 11,

[0070] When the oil content measured by the water content meter is greater than 3000 mg / L, before pulling the oil, the liquid in the free water tank 11 is heated by valley electricity; the heated liquid in the free water tank 11 is mixed back into the oil storage tank 3, and the temperature of the liquid in the oil storage tank 3 reaches the oil pulling temperature of 50-65 o At C, the back-blending is finished and oil pulling is carried out;

[0071] When the oil content measured by the water content meter is not more than 3000 mg / L, the liquid in the free water tank 11 is directly discharged through the water truck; before pulling the oil, the liquid in the oil storage tank 3 is heated until the temperature of the liquid in the oil storage tank 3 reaches the oil pulling temperature of 50-65 o C, oil pulling is carried out.

[0072] Example 8 Method

[0073] On the basis of Examples 1-7, the present invention further provides a method for on-site water separation and remixing in a single well oil extraction system, the method comprising:

[0074] Step 1: before the oil pumping system starts, open the oil inlet valve 4, close the manual valve 1 5, the electric valve 1 7, the electric valve 2 8 and the manual valve 2 10, and the crude oil produced from the oil well enters the oil storage tank 3 through the oil inlet hole 43. The liquid level of the crude oil in the oil storage tank 3 is measured by the liquid level sensor 45. When the liquid level reaches the maximum height of the oil storage tank 3 measured by the liquid level sensor 45, the high liquid level alarm of the oil storage tank 3 is triggered, and the oil inlet valve 4 is closed, and the oil storage of the oil storage tank 3 ends;

[0075] Step 2: The oil storage tank 3 is left to stand to separate oil and water;

[0076] Step 3: Open the manual valve 15, the electric valve 17 and the manual valve 210, and discharge the lower layer liquid of the oil storage tank 3 into the free water tank 11 through the connecting pipe 6. When the liquid level of the free water tank 11 measured by the liquid level sensor 25 reaches the maximum load height, the high liquid level alarm of the free water tank 11 is triggered, and the manual valve 15, the electric valve 17 and the manual valve 210 are closed to stop the liquid in the oil storage tank 3 from flowing into the free water tank 11.

[0077] Step 4: Determine the oil content in the free water tank 11,

[0078] When the oil content measured by the water content meter is greater than 3000 mg / L, before pulling the oil, the liquid in the free water tank 11 is heated by valley electricity; the electric valve 2 8 is opened, and the heated liquid in the free water tank 11 is mixed back into the oil storage tank 3 through the mixing pump 9, and the temperature of the liquid in the oil storage tank 3 reaches the oil pulling temperature of 50-65 o At C, the back-blending is finished and oil pulling is carried out;

[0079] When the oil content measured by the water content meter is not more than 3000 mg / L, open the drain valve 12 to discharge the liquid in the free water tank 11 directly to the water truck through the outlet pipe 36; before pulling the oil, heat the liquid in the oil storage tank 3 until the temperature of the liquid in the oil storage tank 3 reaches the oil pulling temperature of 50-65 o At C, the oil inlet valve 4 is opened, and the crude oil flows into the oil pulling vehicle through the oil outlet pipe 52 for oil pulling.

[0080] Example 9 Additional Features

[0081] On the basis of Examples 1-8, the connecting pipe 6 between the oil storage tank 3 and the free water tank 11 is insulated to reduce heat loss.

[0082] In addition, the valve operating platform and the free water tank 11 sewage valve operating platform are both constructed with DN32 steel pipes, with 100 channel steel welded main frames, anti-slip steel plates on the surface, 40×4 flat steel welded ladders and guardrails.

[0083] The free water tank 11 is also equipped with a lightning protection grounding system. A lightning rod is installed on the top and a galvanized flat steel is used to introduce the grounding grid. The ground is provided with a galvanized grounding electrode and a galvanized flat steel preset grounding grid.

[0084] Technical features not described in the present invention can be achieved through or by adopting existing technologies and will not be described in detail here. Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A method for on-site water separation and remixing in a single well oil extraction system, characterized in that: The method is: Step 1: Crude oil extracted from the oil well enters the oil storage tank (3) through the oil inlet hole (43), and the liquid level of the crude oil in the oil storage tank (3) is measured by the liquid level sensor (45). When the liquid level reaches the maximum height that the oil storage tank (3) can bear, the high liquid level alarm of the oil storage tank (3) is triggered, and the oil storage in the oil storage tank (3) ends; Step 2: The oil storage tank (3) is left to stand to separate oil and water; Step 3: draining the lower layer of liquid in the oil storage tank (3) into the free water tank (11) through the connecting pipe. When the liquid level in the free water tank (11) reaches the maximum load height, the high liquid level alarm of the free water tank (11) is triggered, and the valve on the connecting pipe is closed to stop the liquid in the oil storage tank (3) from flowing into the free water tank (11); Step 4: Determine the oil content in the free water tank (11). When the oil content is greater than 3000 mg / L, before oil extraction, the liquid in the free water tank (11) is heated by valley electricity; the heated liquid in the free water tank (11) is mixed back into the oil storage tank (3); when the temperature of the liquid in the oil storage tank (3) reaches the oil extraction temperature of 50-65°C, the mixing is terminated and oil extraction is performed; When the oil content is not greater than 3000 mg / L, the liquid in the free water tank (11) is directly discharged through a water truck; before oil extraction, the liquid in the oil storage tank (3) is heated, and when the temperature of the liquid in the oil storage tank (3) reaches the oil extraction temperature of 50-65° C., the oil extraction is carried out; Repeat the above steps.

Images