A mobile composite oil displacement injection system for oil fields

Abstract

The utility model relates to an oil field movable composite oil displacement injection system, and relates to the technical field of oil field oil and gas production equipment matching. The switching mechanism includes a cylinder sleeve, a piston is arranged in the cylinder sleeve, the piston is in clearance fit with the cylinder sleeve, the bottom of the cylinder sleeve is connected with an electric push rod through a flange, the telescopic column of the electric push rod is inserted into the cylinder sleeve, and the bottom of the piston is fixedly connected with the telescopic column of the electric push rod. The utility model has the beneficial effects that: the switching mechanism changes the position of the piston through the electric push rod, namely, one of the medicaments can enter the injection wellhead, and the remaining two medicaments can flow back, the switching process does not need to stop the pump and switch the process pipeline, the switching speed is high, the plunger pump without injecting the medicament can flow back the medicament to the medicament tank after switching, the pump outlet pressure is lowered and then the pump is stopped smoothly, or the pump is not stopped according to the length of time, the operation is safe and stable, the switching mechanism adopting the hydraulic cylinder structure is suitable for higher injection pressure, and no leakage is generated.

Description

Technical Field

[0001] This invention relates to the technical field of oilfield oil and gas production equipment, and particularly to a mobile composite oil displacement and injection system for oilfields. Background Technology

[0002] Currently, ternary composite flooding technology is a technique used in oilfield high-efficiency production to improve oil recovery. It mainly involves injecting various multi-stage plugging fluids into the formation during heavy oil production to enhance oil displacement capacity and efficiency, thereby increasing the recovery rate. The current field application process is as follows: Three main agents are injected: a high-temperature foaming agent, a viscosity reducer, and a self-generating heat agent. Fluids are transported by tanker trucks and injected by pump trucks. During injection, the three agents need to be switched back and forth according to design requirements. The main guiding factors for switching are the injection pressure and injection rate. However, in the existing process, the injection pump truck pipeline is directly connected to the tanker truck's connecting pipe. When another agent needs to be injected, the pump needs to be stopped for pipeline switching. Each pipeline switch requires a leak test to ensure normal injection, resulting in a lengthy switching process that affects the oil displacement effect. Summary of the Invention

[0003] To address the problems of long agent switching time and reduced oil displacement efficiency in current ternary composite flooding systems, this invention provides a mobile composite oil displacement injection system for oilfields.

[0004] The technical solution provided by this invention is as follows: it includes a skid, on which injection module A, injection module B and injection module C are installed. Injection module A, injection module B and injection module C have the same structure. Taking injection module A as an example, its structure is described as follows: it includes a reagent tank, which is placed on the skid. A plunger pump is installed on the upper part of the reagent tank. The inlet of the plunger pump is connected to the reagent tank. The outlet of the plunger pump is connected to the reagent input pipeline. A pulse damper and a pressure transmitter are connected to the reagent input pipeline. A flow meter B is installed on the reagent input pipeline.

[0005] It also includes a drug return pipeline connected to the drug tank, and a parallel switching mechanism for the three drug return pipelines and three drug input pipelines of injection module A, injection module B and injection module C; the switching mechanism includes a cylinder liner, a piston is installed inside the cylinder liner, the piston and cylinder liner are clearance fit, the bottom of the cylinder liner is connected to an electric push rod through a flange, the telescopic column of the electric push rod extends into the cylinder liner, and the bottom of the piston is fixedly connected to the telescopic column of the electric push rod;

[0006] The piston has a sliding post at its top, the outer circle of which is smaller than that of the piston. A countersunk hole is formed on the upper end of the sliding post. From top to bottom, the piston's outer circle has annular grooves C, D, E, B, F, G, and A. Annular grooves A, B, and C are interconnected with the countersunk hole via side holes. From top to bottom, the cylinder liner has a drug inlet pipe A, a drug return pipe A, a drug inlet pipe B, a drug return pipe B, a drug return pipe C, and a drug inlet pipe C. Drug inlet pipe A... The drug input line is connected to injection module A; the drug return line A is connected to the drug return line of injection module A; the drug input line B is connected to the drug input line of injection module B; the drug return line B is connected to the drug return line of injection module B; the drug return line C is connected to the drug return line of injection module C; and the drug input line C is connected to the drug input line of injection module C. The piston has sealing rings on both sides of annular grooves A, B, and C.

[0007] The upper part of the cylinder liner is equipped with an external delivery pipe, which is connected to the sliding column through a sealing ring clearance fit. The external delivery pipe is connected to the composite injection pipeline, which is connected to the injection wellhead.

[0008] The electric push rod drives the piston to be in three positions: upper, middle, and lower. When the piston is in the upper position, the annular groove A is connected to the drug input pipe C, the drug input pipe A, the drug return pipe A and the annular groove D are connected, and the drug input pipe B and the drug return pipe B are connected to the annular groove F.

[0009] When the piston is in the middle position, the drug inlet pipe B and the annular groove B are connected, the drug inlet pipe A, the drug return pipe A and the annular groove D are connected, and the drug return pipe C, the drug inlet pipe C and the annular groove G are connected; when the piston is in the lower position, the drug inlet pipe A and the annular groove C are connected, the drug inlet pipe B and the drug return pipe B and the annular groove E are connected, and the drug return pipe C, the drug inlet pipe C and the annular groove G are connected.

[0010] A flow meter A is installed on the aforementioned drug return line.

[0011] The aforementioned electric push rod has a built-in telescopic column stroke electrical pulse output signal. The piston is fixedly connected to the positioning column on the lower end face of the sliding column. The positioning column extends upward out of the cylinder sleeve. The diameter of the output pipe is smaller than that of the cylinder sleeve. The position where the positioning column extends out of the cylinder sleeve is outside the output pipe. A column is fixedly connected on the step between the output pipe and the cylinder sleeve. Three contact switches are arranged vertically on the inner side of the column. A roller is provided on the top of the positioning column.

[0012] The beneficial effects of this invention are as follows: The injection modules A, B, and C for the three agents are mounted together on a single skid, facilitating movement between injection wellheads. Injection modules A, B, and C are connected to a switching mechanism. This switching mechanism, via an electric push rod, changes the piston position, allowing one agent to enter the wellhead while the other two flow back. The switching process requires no pump shutdown or process pipeline switching, resulting in a fast switching speed. The plunger pump not injecting agents can be stopped smoothly after switching, as the agent flows back to the agent tank and the pump outlet pressure decreases. Alternatively, it can be stopped continuously depending on the duration of the operation, ensuring safe and stable operation. The hydraulic cylinder structure of the switching mechanism allows for higher injection pressures without leakage. This invention can also be applied to subsea oil and gas production equipment.

[0013] Thanks to the above-mentioned technical solutions, the switching and injection speed of various agents during the injection process is fast, without the need to adjust the process pipeline or pressurize. The entire injection operation has a short construction period and low energy consumption (after the agent is returned, the outlet pressure of the plunger pump can meet the agent return, and even if the pump is not stopped, the power load of the plunger pump is low), thus achieving the goal of low-carbon mining. Attached Figure Description

[0014] Appendix Figure 1 This is a schematic diagram of the structure of the present invention;

[0015] Appendix Figure 2 This is a structural diagram of injection module A;

[0016] Appendix Figure 3 This is a structural diagram of the switching mechanism;

[0017] Appendix Figure 4 This is a schematic diagram of the plunger structure;

[0018] Appendix Figure 5 This is a partial structural schematic diagram of another embodiment of the present invention;

[0019] Appendix Figure 6 This is a working diagram of the switching mechanism;

[0020] Appendix Figure 7 This is another working diagram for the switching mechanism.

[0021] In the diagram: 1-Bottom skid, 2-Injection module A, 3-Injection module B, 4-Injection module C, 5-Switching mechanism, 6-Composite injection pipeline, 7-Piston, 701-Counterhead, 702-Annular groove A, 703-Side hole, 704-Annular groove B, 705-Annular groove C, 706-Annular groove D, 707-Annular groove E, 708-Annular groove F, 709-Annular groove G, 7010-Sliding column, 8-Cylinder liner, 801-External delivery pipe, 9-Reagent input pipeline, 9a-Reagent input pipe A, 9b-Reagent input pipe B, 9 c-Inlet pipe C, 10-Inlet pipe B, 10a-Inlet pipe A, 10b-Inlet pipe B, 10c-Inlet pipe C, 11-Flow meter A, 12-Flow meter B, 13-Pressure transmitter, 14-Pulse damper, 15-Electric push rod, 151-Telescopic column, 16-Plunger pump, 17-Inlet tank, 18-Positioning column, 19-Roller, 20-Column, 21-Contact switch, 22-Injection wellhead. Detailed Implementation

[0022] like Figures 1-7 As shown, a mobile composite oil displacement injection system for oil fields includes a skid 1. Injection modules A2, B3, and C4 are installed on the skid 1. Injection modules A2, B3, and C4 have the same structure. Taking injection module A2 as an example, its structure is described as follows: It includes a chemical tank 17, which is placed on the skid 1. A plunger pump 16 is installed on the upper part of the chemical tank 17. The inlet of the plunger pump 16 is connected to the chemical tank 17, and the outlet of the plunger pump 16 is connected to the chemical input pipeline 9. A pulse damper 14 and a pressure transmitter 13 are connected to the chemical input pipeline 9. A flow meter B12 is installed on the chemical input pipeline 9.

[0023] It also includes a drug return pipeline 10, which is connected to a drug tank 17, and a parallel switching mechanism 5 for the three drug return pipelines 10 and three drug input pipelines 9 of injection modules A2, B3 and C4.

[0024] The switching mechanism 5 includes a cylinder liner 8, a piston 7 is provided inside the cylinder liner 8, the piston 7 is clearance-fitted with the cylinder liner 8, the bottom of the cylinder liner 8 is connected to an electric push rod 15 through a flange, the telescopic column 151 of the electric push rod 15 extends into the cylinder liner 8, and the bottom of the piston 7 is fixedly connected to the telescopic column 151 of the electric push rod 15.

[0025] The piston 7 has a sliding post 7010 at its top. The outer circle of the sliding post 7010 is smaller than that of the piston 7. A countersunk hole 701 is opened downward on the upper end of the sliding post 7010. The outer circle of the piston 7 has annular grooves C705, D706, E707, B704, F708, G709, and A702 from top to bottom. Among them, annular grooves A702, B704, and C705 are interconnected with the countersunk hole 701 through side holes 703. The cylinder liner 8 is connected to the cylinder liner from top to bottom. The drug input pipe A9a, drug return pipe A10a, drug input pipe B9b, drug return pipe B10b, drug return pipe C10c and drug input pipe C9c are connected. Drug input pipe A9a is connected to the drug input line 9 of injection module A2. Drug return pipe A10a is connected to the drug return line 10 of injection module A2. Drug input pipe B9b is connected to the drug input line 9 of injection module B3. Drug return pipe B10b is connected to the drug return line 10 of injection module B3. Drug return pipe C10c is connected to the drug return line 10 of injection module C4. Drug input pipe C9c is connected to the drug input line 9 of injection module C4.

[0026] Piston 7 is provided with sealing rings on both sides of annular groove A702, annular groove B704 and annular groove C705;

[0027] The cylinder liner 8 is provided with an external delivery pipe 801 on the upper part. The external delivery pipe 801 is connected to the sliding column 7010 through a sealing ring clearance fit. The external delivery pipe 801 is connected to the composite injection pipeline 6, and the composite injection pipeline 6 is connected to the injection wellhead 22.

[0028] The electric push rod 15 drives the piston 7 to be in three positions: upper, middle, and lower. When the piston 7 is in the upper position, the annular groove A702 is connected to the drug input pipe C9c. The drug from the injection module C4 enters the piston 7 and the external delivery pipe 801 and is injected into the formation. The drug input pipe A9a, the drug return pipe A10a and the annular groove D706 are connected. The drug input pipe B9b and the drug return pipe B10b are connected to the annular groove F708. The drugs from the injection modules A2 and B3 flow back to their respective drug tanks 17.

[0029] When piston 7 is in the middle position, drug input pipe B9b and annular groove B704 are connected, drug input pipe A9a, drug return pipe A10a and annular groove D706 are connected, and drug return pipe C10c and drug input pipe C9c and annular groove G709 are connected.

[0030] When piston 7 is in the lower position, the drug input pipe A9a is connected to the annular groove C705, the drug input pipe B9b and the drug return pipe B10b are connected to the annular groove E707, and the drug return pipe C10c, the drug input pipe C9c and the annular groove G709 are connected.

[0031] The injection modules A2, B3, and C4 for the three agents are mounted together on a skid 1. These modules are connected to a switching mechanism 5. The switching mechanism 5 changes the position of the piston 7 via an electric push rod 15, allowing one agent to enter the injection wellhead 22 while the other two agents flow back. During the switching process, there is no need to stop the pump or switch the process pipeline. The switching speed is fast. The plunger pump 16, which does not inject agents, can smoothly stop after the agent flows back to the agent tank 17 and the pump outlet pressure drops, or it can choose not to stop the pump depending on the duration. The operation is safe and stable. The switching mechanism 5, which adopts a hydraulic cylinder structure, can adapt to higher injection pressures without leakage.

[0032] A flow meter A11 is installed on the drug return line 10. The flow rate of each drug during return is included and subtracted from the flow meter A12 on the drug input line 9. This does not affect the metered injection flow rate.

[0033] The electric push rod 15 has a built-in telescopic column 151 that outputs an electrical pulse signal. The piston 7 is fixedly connected to the positioning column 18 on the lower end face of the sliding column 7010. The piston 7 is at constant pressure at this position. The positioning column 18 extends upward out of the cylinder liner 8. The diameter of the output pipe 801 is smaller than that of the cylinder liner 8. The position where the positioning column 18 extends out of the cylinder liner 8 is outside the output pipe 801. The column 20 is fixedly connected on the step between the output pipe 801 and the cylinder liner 8. The inside of the column 20 is provided with three vertically arranged contact switches 21. The top of the positioning column 18 is provided with a roller 19. When the roller 19 passes through the three contact switches 21, it sends a signal, which is mutually verified with the electrical pulse signal of the electric push rod 15 to ensure safe and reliable operation.

Claims

1. A mobile composite oil displacement injection system for oilfields, comprising a bottom skid (1), characterized in that: Injection module A (2), injection module B (3) and injection module C (4) are installed on the skid (1). Injection module A (2), injection module B (3) and injection module C (4) have the same structure. Taking injection module A (2) as an example, its structure is explained: It includes a medicine tank (17), which is placed on the skid (1). A plunger pump (16) is installed on the upper part of the medicine tank (17). The inlet of the plunger pump (16) is connected to the medicine tank (17), and the outlet of the plunger pump (16) is connected to the medicine input pipeline (9). A pulse damper (14) and a pressure transmitter (13) are connected to the medicine input pipeline (9). A flow meter B (12) is installed on the medicine input pipeline (9). It also includes a drug return pipeline (10), which is connected to the drug tank (17). The three drug return pipelines (10) and three drug input pipelines (9) of the injection module A (2), injection module B (3) and injection module C (4) are simultaneously connected in parallel and switched by a mechanism (5). The switching mechanism (5) includes a cylinder liner (8), a piston (7) is provided inside the cylinder liner (8), the piston (7) and the cylinder liner (8) are clearance-fitted, the bottom of the cylinder liner (8) is connected to an electric push rod (15) through a flange, the telescopic column (151) of the electric push rod (15) extends into the cylinder liner (8), and the bottom of the piston (7) is fixedly connected to the telescopic column (151) of the electric push rod (15); The piston (7) has a sliding post (7010) at its top. The outer circle of the sliding post (7010) is smaller than that of the piston (7). The upper end of the sliding post (7010) has a countersunk hole (701) facing downwards. The outer circle of the piston (7) has annular grooves C (705), D (706), E (707), B (704), F (708), G (709), and A (702) from top to bottom. In the middle, annular grooves A (702), B (704), and C (705) are interconnected with the countersunk hole (701) through side holes (703). The cylinder liner (8) is connected from top to bottom to a drug inlet pipe A (9a), a drug return pipe A (10a), a drug inlet pipe B (9b), a drug return pipe B (10b), a drug return pipe C (10c), and a drug inlet pipe C (9c). Drug inlet pipe A (9a) The drug input line (9) of the injection module A (2) is connected; the drug return line A (10a) is connected to the drug return line (10) of the injection module A (2); the drug input line B (9b) is connected to the drug input line (9) of the injection module B (3); the drug return line B (10b) is connected to the drug return line (10) of the injection module B (3); the drug return line C (10c) is connected to the drug return line (10) of the injection module C (4); and the drug input line C (9c) is connected to the drug input line (9) of the injection module C (4). The piston (7) is provided with sealing rings on both sides of the annular groove A (702), annular groove B (704) and annular groove C (705); The cylinder liner (8) is provided with an external delivery pipe (801) on the upper part. The external delivery pipe (801) is connected to the sliding column (7010) through a sealing ring gap fit. The external delivery pipe (801) is connected to the composite injection line (6). The composite injection line (6) is connected to the injection wellhead (22). The electric push rod (15) drives the piston (7) to be in three positions: upper, middle and lower. When the piston (7) is in the upper position, the annular groove A (702) is connected to the drug input pipe C (9c), the drug input pipe A (9a), the drug return pipe A (10a) is connected to the annular groove D (706), and the drug input pipe B (9b) and the drug return pipe B (10b) are connected to the annular groove F (708). When the piston (7) is in the middle position, the drug input pipe B (9b) and the annular groove B (704) are connected, the drug input pipe A (9a), the drug return pipe A (10a) and the annular groove D (706) are connected, and the drug return pipe C (10c), the drug input pipe C (9c) and the annular groove G (709) are connected. When the piston (7) is in the lower position, the drug input pipe A (9a) and the annular groove C (705) are connected, the drug input pipe B (9b) and the drug return pipe B (10b) are connected to the annular groove E (707), and the drug return pipe C (10c), the drug input pipe C (9c) and the annular groove G (709) are connected.

2. The mobile composite oil displacement and injection system for oilfields according to claim 1, characterized in that: A flow meter A (11) is installed on the drug return line (10).

3. The mobile composite oil displacement injection system for oilfields according to claim 1, characterized in that: The electric push rod (15) has a telescopic column (151) with a stroke electric pulse output signal. The piston (7) is fixedly connected to the positioning column (18) on the lower end face of the sliding column (7010). The positioning column (18) extends upward out of the cylinder sleeve (8). The diameter of the output pipe (801) is smaller than that of the cylinder sleeve (8). The position where the positioning column (18) extends out of the cylinder sleeve (8) is outside the output pipe (801). The column (20) is fixedly connected on the step between the output pipe (801) and the cylinder sleeve (8). The inside of the column (20) is provided with three contact switches (21) arranged vertically. The top of the positioning column (18) is provided with a roller (19).

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