Device and method for testing the retention effect of wax removal and prevention agents

Abstract

The present invention provides a device and method for testing the retention effect of a paraffin removal and prevention agent. The device comprises a sand filling device, a first injection mechanism, a second injection mechanism, and a recovery container. The sand filling device comprises a sand filling chamber with openings at both ends, the sand filling chamber containing simulated sand. The first injection mechanism is detachably connected to the inlet end or the outlet end of the sand filling chamber, the second injection mechanism is detachably connected to the inlet end of the sand filling chamber, and the recovery container is detachably connected to the outlet end of the sand filling chamber. The first injection mechanism is used to inject waxy crude oil into the sand filling device to simulate the process of oil reservoir formation or crude oil precipitation. The second injection mechanism is used to inject the paraffin removal and prevention agent into the sand filling device. The recovery container is used to accommodate simulated produced crude oil flowing out of the sand filling device to compare the simulated produced crude oil with the initial crude oil. The present invention can evaluate and confirm the paraffin removal and prevention effect of the paraffin removal and prevention agent on waxy crude oil under formation conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of oil production engineering, and in particular to a device and method for testing the retention effect of a wax removal and prevention agent. Background Art

[0002] During the oil and gas production process, as waxy crude oil flows from the formation into the wellbore and then into the wellbore, it is lifted to the surface, where its pressure and temperature continuously decrease. When the pressure and temperature drop below a certain level, the solubility equilibrium of paraffin in the crude oil is disrupted, exceeding the solubility saturation of paraffin in the crude oil. This causes paraffin to precipitate from the crude oil, a condition known as wax deposition in the well. This paraffin deposition can reduce the oil flow path in the well, increase the resistance to the pump rod, and increase the load. If wax removal is not timely, severe wax deposition can cause the pump rod to become stuck in the tubing, or even break.

[0003] In the existing technology, the use of paraffin removal and prevention agents to remove paraffin from oil wells is a common paraffin removal and prevention technology in oil field applications. That is, the paraffin removal and prevention agent is usually added from the annular space to utilize the chemical reaction between the paraffin removal and prevention agent and wax to achieve paraffin removal and prevention effects.

[0004] However, as the construction work progressed, the wax removal and prevention effect of the paraffin removal and prevention agent on waxy crude oil under formation conditions could not be evaluated and confirmed. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a paraffin removal and prevention agent retention effect testing device and method, which can evaluate and confirm the paraffin removal and prevention effect of the paraffin removal and prevention agent on waxy crude oil under formation conditions during construction operations.

[0006] In order to achieve the above-mentioned technical effects, in the first aspect, the present invention provides a device for testing the retention effect of a wax removal and prevention agent, comprising a sand filling device, a first injection mechanism, a second injection mechanism and a recovery container; the sand filling device has a sand filling cavity with openings at both ends, the sand filling cavity is filled with simulated sand, the first injection mechanism is detachably connected to the inlet end of the sand filling cavity or the outlet end of the sand filling cavity, the second injection mechanism is detachably connected to the inlet end of the sand filling cavity, and the recovery container is detachably connected to the outlet end of the sand filling cavity.

[0007] The first injection mechanism is used to inject waxy crude oil into the sand filling device to simulate the oil reservoir formation process or the crude oil precipitation process; the second injection mechanism is used to inject a wax removal and prevention agent into the sand filling device; the recovery container is used to accommodate the simulated produced crude oil flowing out of the sand filling device to compare the simulated produced crude oil with the initial crude oil.

[0008] In the above-mentioned paraffin removal and preventive agent retention effect test device, optionally, the first injection mechanism includes a first pump body and a first intermediate container filled with waxy crude oil, one end of the first intermediate container is connected to the first pump body, and the other end of the first intermediate container is connected to the sand filling device; and

[0009] The second injection mechanism includes a second pump body and a second intermediate container filled with a wax removal and prevention agent. One end of the second intermediate container is connected to the second pump body, and the other end of the second intermediate container is connected to the sand filling device.

[0010] In the above-mentioned paraffin removal and preventative agent retention effect test device, optionally, the first intermediate container has a first cavity inside, a first reciprocating piston is provided in the first cavity, the first piston separates the first cavity into a first space and a second space, the first space is connected to the first pump body, and the second space is connected to the sand filling device; and / or,

[0011] The second intermediate container has a second cavity inside, and a second reciprocating piston is provided in the second cavity. The second piston divides the second cavity into a third space and a fourth space. The third space is connected to the second pump body, and the fourth space is connected to the sand filling device.

[0012] In the above-mentioned paraffin removal and prevention agent retention effect testing device, optionally, one end of the first pump body facing away from the first intermediate container and one end of the second pump body facing away from the second intermediate container are both in communication with formation water.

[0013] In the above-mentioned paraffin removal and prevention agent retention effect test device, it is optional to further include: a third injection mechanism, the third injection mechanism includes a third pump body, one end of the third pump body is connected to the formation water, and the other end of the third pump body is connected to the sand filling device to inject the formation water into the sand filling device.

[0014] In the above-mentioned paraffin removal and preventive agent retention effect testing device, optionally, the first injection mechanism, the second injection mechanism, and the third injection mechanism are connected to the sand filling device through a multi-way valve.

[0015] In the above-mentioned paraffin removal and preventive agent retention effect test device, optionally, it further includes a pressurizing device, which is connected to the outlet end of the sand filling cavity and is used to apply simulated bottom hole flow pressure to the sand filling cavity.

[0016] In the above-mentioned wax removal and preventative agent retention effect test device, optionally, the pressurizing device includes a back-pressure valve and a hand pump connected to the back-pressure valve, and the hand pump is used to set the pressure for the back-pressure valve.

[0017] In a second aspect, the present invention provides a method for testing the retention effect of a paraffin removal and prevention agent, which is applied to the paraffin removal and prevention agent retention effect testing device as described above, comprising:

[0018] Waxy crude oil is injected into the sand packing device through a first injection mechanism to simulate the oil reservoir formation process.

[0019] The paraffin removal and prevention agent is injected into the sand filling device through the second injection mechanism to simulate the process of the paraffin removal and prevention agent entering the formation.

[0020] The first injection mechanism is connected to the outlet end of the sand filling cavity of the sand filling device, and waxy crude oil is injected into the sand filling device through the first injection mechanism to simulate the process of waxy crude oil precipitation.

[0021] The components of the simulated produced crude oil and the initial crude oil flowing out of the sand packing device are compared to determine the retention degree of the paraffin removal and prevention agent in the formation.

[0022] The present invention provides a device and method for testing the retention effect of a paraffin removal and prevention agent. The device comprises a sand filling device, a first injection mechanism, a second injection mechanism, and a recovery container. The sand filling device comprises a sand filling chamber with two open ends, the chamber containing simulated sand. The first injection mechanism is detachably connected to the inlet or outlet of the sand filling chamber, the second injection mechanism is detachably connected to the inlet of the sand filling chamber, and the recovery container is detachably connected to the outlet of the sand filling chamber. With this arrangement, the first injection mechanism is used to inject waxy crude oil into the sand filling device to simulate the reservoir formation process or crude oil precipitation process; the second injection mechanism is used to inject the paraffin removal and prevention agent into the sand filling device; and the recovery container is used to receive simulated production crude oil flowing out of the sand filling device for comparison with the initial crude oil. Therefore, the present invention can evaluate the paraffin removal and prevention effect of a paraffin removal and prevention agent on waxy crude oil under formation conditions and determine the degree of paraffin removal and prevention agent retention in the formation.

[0023] The construction of the present invention and other objects and advantageous effects thereof will become more apparent through the description of the preferred embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0025] Figure 1This is a structural schematic diagram of a device for testing the retention effect of a wax removal and preventative agent provided in Example 1 of the present invention;

[0026] Figure 2 2 is a schematic structural diagram of a first pump body of a device for testing the retention effect of a paraffin removal and preventative agent provided in Example 1 of the present invention;

[0027] Figure 3 2 is a schematic structural diagram of a first intermediate container of a device for testing the retention effect of a paraffin removal and preventative agent provided in Example 1 of the present invention;

[0028] Figure 4 This is another structural schematic diagram of the device for testing the retention effect of a wax removal and preventative agent provided in the first embodiment of the present invention;

[0029] Figure 5 This is another structural schematic diagram of the device for testing the retention effect of a wax removal and preventative agent provided in the first embodiment of the present invention;

[0030] Figure 6 This is another structural schematic diagram of the device for testing the retention effect of a wax removal and preventative agent provided in the first embodiment of the present invention;

[0031] Figure 7 This is a flow chart of a method for testing the retention effect of a wax removal and preventative agent provided in the second embodiment of the present invention;

[0032] Figure 8 This is another flow chart of a method for testing the retention effect of a wax removal and preventative agent provided in the second embodiment of the present invention;

[0033] Figure 9 This is a comparison chart of the components of the simulated produced crude oil and the initial crude oil when the paraffin removal and prevention agent retention effect testing method provided in Example 2 of the present invention is applied to the paraffin removal and prevention agent retention effect testing device provided in Example 1 of the present invention.

[0034] Description of reference numerals:

[0035] 100-Test device for the retention effect of wax remover and wax inhibitor;

[0036] 10-Sand filling device;

[0037] 101-sand filling cavity;

[0038] 1011-entrance end;

[0039] 1012-exit port;

[0040] 20- first injection mechanism;

[0041] 201-first pump body;

[0042] 2011-First Knob;

[0043] 2012-Second Knob;

[0044] 2013-Display screen;

[0045] 202-first intermediate container;

[0046] 2021-first cavity;

[0047] 20211-First Space;

[0048] 20212-Second Space;

[0049] 2022-First Piston;

[0050] 30- second injection mechanism;

[0051] 301-second pump body;

[0052] 302-second intermediate container;

[0053] 40-Recycling container;

[0054] 50-formation water;

[0055] 60-third pump body;

[0056] 701-first multi-way valve;

[0057] 702 - second multi-way valve;

[0058] 703- one-way valve;

[0059] 704-two-way valve;

[0060] 80- pressurizing device;

[0061] 801-back pressure valve;

[0062] 802-hand pump;

[0063] 90-pressure gauge. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present invention. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and should not be understood as limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The embodiments of the present invention are described in detail below in conjunction with the drawings.

[0065] In the present invention, unless otherwise specified or limited, terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; they may refer to mechanical connections, direct connections, or indirect connections through an intermediate medium; they may refer to internal communication between two components or the interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0066] Example 1

[0067] Figure 1 This is a structural schematic diagram of a device for testing the retention effect of a wax removal and preventative agent provided in Example 1 of the present invention. Figure 2 It is a structural schematic diagram of the first pump body of the paraffin removal and prevention agent retention effect testing device provided in Example 1 of the present invention. Figure 3 It is a structural schematic diagram of the first intermediate container of the paraffin removal and preventative agent retention effect testing device provided in Example 1 of the present invention. Figure 4 This is another structural schematic diagram of the device for testing the retention effect of a wax removal and preventative agent provided in Example 1 of the present invention. Figure 5 This is another structural schematic diagram of the device for testing the retention effect of the wax removal and preventative agent provided in the first embodiment of the present invention. Figure 6 This is another structural schematic diagram of the device for testing the retention effect of a wax removal and preventative agent provided in the first embodiment of the present invention.

[0068] like Figure 1 As shown, the first embodiment of the present invention provides a device 100 for testing the retention effect of a wax removal and preventative agent, comprising a sand filling device 10 , a first injection mechanism 20 , a second injection mechanism 30 and a recovery container 40 .

[0069] The sand filling device 10 has a sand filling chamber 101 with openings at both ends. The sand filling chamber 101 is filled with simulated sand. The first injection mechanism 20 is detachably connected to the inlet end 1011 of the sand filling chamber 101 or the outlet end 1012 of the sand filling chamber 101. The second injection mechanism 30 is detachably connected to the inlet end 1011 of the sand filling chamber 101. The recovery container 40 is detachably connected to the outlet end 1012 of the sand filling chamber 101.

[0070] The simulated sand in the sand-filling cavity 101 may be a gravel-like material, such as ceramsite or quartz sand, etc. In some embodiments of the present application, the simulated sand may be quartz sand.

[0071] In a specific implementation, a formation model can be formed by filling the sand filling chamber 101 of the sand filling device 10 with quartz sand of a certain mesh size. For example, the sand filling chamber 101 of the sand filling device 10 can be filled with quartz sand of 200-400 mesh size. For example, the mesh size of the quartz sand in this embodiment can be 200 mesh, 300 mesh, 400 mesh, etc. The embodiment of the present invention does not limit the mesh size of the quartz sand, nor is it limited to the above example.

[0072] It should be noted that mesh number refers to the particle size or coarseness of the material. The larger the mesh number, the finer the material particle size; the smaller the mesh number, the larger the material particle size.

[0073] The first injection mechanism 20 is used to inject waxy crude oil into the sand packing device 10 to simulate the reservoir formation process or crude oil precipitation process. The second injection mechanism 30 is used to inject a paraffin removal and prevention agent into the sand packing device 10 to simulate the process of the paraffin removal and prevention agent entering the formation. The recovery container 40 is used to accommodate the simulated produced crude oil flowing out of the sand packing device 10 to compare the composition of the simulated produced crude oil with that of the original crude oil.

[0074] Specifically, the first injection mechanism 20 includes a first pump body 201 and a first intermediate container 202 filled with waxy crude oil. One end of the first intermediate container 202 is connected to the first pump body 201 , and the other end of the first intermediate container 202 is connected to the sand filling device 10 .

[0075] Similarly, the second injection mechanism 30 includes a second pump body 301 and a second intermediate container 302 filled with a wax removal and preventative agent. One end of the second intermediate container 302 is connected to the second pump body 301 , and the other end of the second intermediate container 302 is connected to the sand filling device 10 .

[0076] When the first injection mechanism 20 is detachably connected to the inlet end 1011 of the sand-filling chamber 101, the waxy crude oil in the first intermediate container 202 is injected into the sand-filling model 10 via the first pump body 201, thereby simulating the reservoir formation process. Specifically, the first pump body 201 pumps formation water 50 into the first space 20211 of the first intermediate container 202. The formation water 50 in the first space 20211 pushes the first piston 2022 toward the second space 20212, thereby injecting the waxy crude oil stored in the second space 20212 into the sand-filling chamber 101.

[0077] When the first injection mechanism 20 is detachably connected to the outlet end 1012 of the sand-filling chamber 101, the waxy crude oil in the first intermediate container 202 is injected into the sand-filling model 10 via the first pump body 201, thereby simulating the crude oil precipitation process. Specifically, after the sand-filling device 10 is rotated 180 degrees, the outlet end 1012 of the sand-filling chamber 101 of the sand-filling device 10 is connected to the first injection mechanism 20. The first pump body 201 pumps formation water 50 into the first space 20211 of the first intermediate container 202. The formation water 50 in the first space 20211 pushes the first piston 2022 toward the second space 20212, thereby injecting the waxy crude oil stored in the second space 20212 into the sand-filling chamber 101. The waxy crude oil is then injected from the outlet end 1012 of the sand-filling chamber 10 to the inlet end 1011, simulating the crude oil precipitation process. In other words, the injection direction of the waxy crude oil during the simulated crude oil precipitation process is opposite to the injection direction of the waxy crude oil during the simulated reservoir formation process.

[0078] It should be noted that the present invention does not limit the specific types of the first pump body 201 and the second pump body 301. For example, they can be plunger pumps, etc. Taking the first pump body 201 as an example, Figure 2 As shown, the first pump body 201 can also be provided with a first knob 2011, a second knob 2012 and a display screen 2013. The first knob 2011 and the second knob 2012 are respectively used to adjust parameters such as time and flow rate of the first pump body 201, and the display screen is used to display specific values ​​of parameters such as time and flow rate to present them to the user.

[0079] Therefore, in actual use, the time and flow rate of the first pump body 201 and the second pump body 301 can be flexibly set to inject waxy crude oil or wax removal and prevention agent into the sand filling cavity 101 of the sand filling model 10.

[0080] like Figure 3As shown, the interior of the first intermediate container 202 has a first cavity 2021, and a first piston 2022 that can move back and forth is provided in the first cavity 2021. The first piston 2022 separates the first cavity 2021 into a first space 20211 and a second space 20212. The first space 20211 is connected to the first pump body 201, and the second space 20212 is connected to the sand filling device 10.

[0081] Similarly, the interior of the second intermediate container 302 has a second cavity, and a second piston that can move back and forth is provided in the second cavity. The second piston divides the second cavity into a third space and a fourth space. The third space is connected to the second pump body 301, and the fourth space is connected to the sand filling device 10 (not shown in the figure).

[0082] It should be noted that the end of the first pump body 201 away from the first intermediate container 202 and the end of the second pump body 301 away from the second intermediate container 302 are both in communication with the formation water 50 .

[0083] Specifically, the first pump body 201 pumps formation water 50 into the first space 20211 of the first intermediate container 202. The formation water 50 in the first space 20211 pushes the first piston 2022 toward the second space 20212, thereby injecting the waxy crude oil stored in the second space 20212 into the sand filling cavity 101. Similarly, the second pump body 301 pumps formation water 50 into the third space 30211 of the second intermediate container 302. The formation water 50 in the third space 30211 pushes the second piston 3022 toward the fourth space 30212, thereby injecting the paraffin removal and preventative agent stored in the fourth space 30212 into the sand filling cavity 101.

[0084] In order to increase the accuracy of simulating the reservoir formation process, such as Figure 4 As shown, the paraffin removal and preventative agent retention effect testing device 100 provided in an embodiment of the present invention further includes a third injection mechanism. The third injection mechanism includes a third pump body 60. One end of the third pump body 60 is connected to the formation water 50, and the other end of the third pump body 60 is connected to the sand filling device 10 to inject the formation water 50 into the sand filling device 10.

[0085] Therefore, the formation water 50 is injected into the sand packing model 10 through the third pump body 60 , and the waxy crude oil in the first intermediate container 202 is injected into the sand packing model 10 through the first pump body 201 , thereby more accurately simulating the reservoir formation process.

[0086] It should be noted that the first injection mechanism 20 , the second injection mechanism 30 , and the third injection mechanism may also be connected to the sand filling device 10 via a multi-way valve.

[0087] The communication relationship between the first injection mechanism 20, the second injection mechanism 30 and the third injection mechanism and the sand filling device 10 includes but is not limited to the following two possible implementations:

[0088] One possible implementation is that the outlet ends of the first injection mechanism 20 , the second injection mechanism 30 and the third injection mechanism are simultaneously connected to the inlet end of the sand filling device 10 through a multi-way valve.

[0089] Another possible implementation is: Figure 5 As shown, the outlet ends of the first injection mechanism 20 and the second injection mechanism 30 are connected through the second multi-way valve 702 , and the outlet end of the second multi-way valve 702 is connected to the inlet end of the sand filling device 10 through the first multi-way valve 701 .

[0090] When the multi-way valve is closed, the first injection mechanism 20 and the sand filling device 10, the third injection mechanism 30 and the sand filling device 10, and the third injection mechanism and the sand filling device 10 are all in a cut-off state; when the multi-way valve is opened, the first injection mechanism 20 and the sand filling device 10, the third injection mechanism 30 and the sand filling device 10, and the third injection mechanism and the sand filling device 10 are all in a flow state.

[0091] As an optional embodiment, the outlet ends of the first injection mechanism 10, the second injection mechanism 20, and the third injection mechanism may also be provided with a one-way valve 703. When the one-way valve 703 is closed, the first injection mechanism 20 and the sand filling device 10, the third injection mechanism 30 and the sand filling device 10, and the third injection mechanism and the sand filling device 10 are all cut off; when the one-way valve 703 is opened, the first injection mechanism 10, the second injection mechanism 20, and the third injection mechanism can flow one-way into the sand filling device 10.

[0092] As an optional embodiment, the paraffin removal and preventative agent retention effect testing device 100 provided in the embodiment of the present invention may further include multiple two-way valves 704. When the two-way valves 704 are closed, both ends of the two-way valves 704 are in a cutoff state; when the two-way valves 704 are open, both ends of the two-way valves 704 allow bidirectional flow.

[0093] like Figure 6 As shown, the paraffin removal and preventive agent retention effect testing device 100 provided in an embodiment of the present invention may further include a pressurizing device 80 , which is connected to the outlet end 1012 of the sand filling cavity 101 and is used to apply simulated bottom hole flow pressure to the sand filling cavity 101 .

[0094] Specifically, the pressurizing device 80 may include a back-pressure valve 801 and a hand pump 802 connected to the back-pressure valve 801. The hand pump 802 is used to set the pressure of the back-pressure valve 801. The pressure of the back-pressure valve 801 can be set as the bottom hole flow pressure. For example, the pressure of the back-pressure valve can be set to 15 MPa as the bottom hole flow pressure.

[0095] It should be noted that the pressurizing device 80 can be an electronic pressurizing device or the manual pressurizing device described above, as long as it can simulate the bottom hole flow pressure. The embodiment of the present invention does not limit the specific type of the pressurizing device 80, nor is it limited to the above example.

[0096] In addition, the outlet and inlet of the sand filling model 10 can also be provided with pressure gauges 90 respectively. Figure 6 As shown, the pressure gauge 90 near the pressurizing device 80 can be used to detect the pressure setting of the pressurizing device 80 on one end of the sand-filled model 10 , and the pressure gauge 90 near the pressurizing device 80 can be used to monitor the pressure at the other end of the sand-filled model 10 .

[0097] It should be noted that the particle size of the simulated sand filled in the sand filling cavity 101 can match the particle size of the stratum where the simulated oil reservoir is located, so as to further improve the accuracy of the simulation test.

[0098] A first embodiment of the present invention provides a device for testing the retention effect of a paraffin removal and prevention agent. The device comprises a sand filling device, a first injection mechanism, a second injection mechanism, and a recovery container. The sand filling device comprises a sand filling chamber with two open ends, the chamber containing simulated sand. The first injection mechanism is detachably connected to the inlet or outlet of the sand filling chamber, the second injection mechanism is detachably connected to the inlet of the sand filling chamber, and the recovery container is detachably connected to the outlet of the sand filling chamber. With this arrangement, the first injection mechanism is used to inject waxy crude oil into the sand filling device to simulate the reservoir formation process or crude oil precipitation process; the second injection mechanism is used to inject the paraffin removal and prevention agent into the sand filling device; and the recovery container is used to receive simulated produced crude oil flowing out of the sand filling device for comparison of the composition of the simulated produced crude oil with that of the initial crude oil. Therefore, the embodiment of the present invention can evaluate the paraffin removal and prevention effect of a paraffin removal and prevention agent on waxy crude oil under formation conditions and determine the degree of paraffin removal and prevention agent retention in the formation.

[0099] Example 2

[0100] Figure 7 This is a flow chart of a method for testing the retention effect of a wax removal and preventative agent provided in the second embodiment of the present invention. Figure 8 This is another flow chart of the method for testing the retention effect of a wax removal and preventative agent provided in the second embodiment of the present invention. Figure 9This is a comparison chart of the components of the simulated produced crude oil and the initial crude oil when the paraffin removal and prevention agent retention effect testing method provided in Example 2 of the present invention is applied to the paraffin removal and prevention agent retention effect testing device provided in Example 1 of the present invention.

[0101] like Figure 7 As shown, based on the above embodiment 1, embodiment 2 of the present invention further provides a method for testing the retention effect of a wax removal and prevention agent, which can be applied to the device for testing the retention effect of a wax removal and prevention agent of embodiment 1. The method may specifically include:

[0102] S101: Injecting waxy crude oil into the sand filling device through a first injection mechanism to simulate the oil reservoir formation process.

[0103] The paraffin removal and preventative agent retention test device 100 includes a sand filling device 10 having a sand filling chamber 101 filled with simulated sand. A first injection mechanism 20 is detachably connected to an inlet end 1011 of the sand filling chamber 101. A second injection mechanism 30 is detachably connected to the inlet end 1011 of the sand filling chamber 101. A recovery container 40 is detachably connected to an outlet end 1012 of the sand filling chamber 101.

[0104] The simulated sand in the sand filling cavity 101 can be ceramsite or quartz sand. As an optional embodiment, the simulated sand is quartz sand.

[0105] In a specific implementation, a formation model can be formed by filling the sand filling chamber 101 of the sand filling device 10 with quartz sand of a certain mesh size. For example, the sand filling chamber 101 of the sand filling device 10 can be filled with quartz sand of 200-400 mesh size. For example, the mesh size of the quartz sand in this embodiment can be 200 mesh, 300 mesh, 400 mesh, etc. The embodiment of the present invention does not limit the mesh size of the quartz sand, nor is it limited to the above example.

[0106] The first injection mechanism 20 includes a first pump body 201 and a first intermediate container 202 filled with waxy crude oil. One end of the first intermediate container 202 is connected to the first pump body 201 , and the other end of the first intermediate container 202 is connected to the sand filling device 10 .

[0107] For example, the flow rate of the first pump body 201 can be set to 2 mL / min and the injection time can be set to 10 h. The waxy crude oil in the first intermediate container 202 can be injected into the sand filling device 10 through the first pump body 201 to simulate the oil reservoir formation process.

[0108] S102: injecting a paraffin removal and prevention agent into the sand filling device through a second injection mechanism to simulate a process in which the paraffin removal and prevention agent enters the formation.

[0109] The second injection mechanism 30 includes a second pump body 301 and a second intermediate container 302 filled with a wax removal and preventative agent. One end of the second intermediate container 302 is connected to the second pump body 301 , and the other end of the second intermediate container 302 is connected to the sand filling device 10 .

[0110] Specifically, the flow rate of the second pump body 301 can be set to 2 mL / min and the injection time can be set to 5 hours. The paraffin removal and prevention agent in the second intermediate container 302 can be injected into the sand filling device 10 through the second pump body 301 to simulate the process of the paraffin removal and prevention agent entering the formation.

[0111] S103: Connecting the first injection mechanism to the outlet of the sand filling chamber of the sand filling device, and injecting waxy crude oil into the sand filling device through the first injection mechanism to simulate the waxy crude oil precipitation process.

[0112] After the sand-filling device is rotated 180°, the outlet end 1012 of the sand-filling chamber 101 of the sand-filling device 10 is connected to the first injection mechanism 20. The flow rate of the first pump body 201 can be set to 0.5 mL / min and the injection time can be set to 40 hours. The waxy crude oil in the first intermediate container 202 is injected into the sand-filling device 10 through the first pump body 201 to simulate the crude oil precipitation process.

[0113] S104: Compare the components of the simulated produced crude oil flowing out of the sand packing device and the initial crude oil to determine the retention degree of the paraffin removal and prevention agent in the formation.

[0114] For example, Figure 9 This is a comparison chart of the composition of the simulated crude oil produced and the initial crude oil at step S103, using the first pump 201 at a flow rate of 0.5 mL / min and an injection time of 30 minutes. By comparing the composition of the simulated crude oil produced by the sand packing device with the initial crude oil, the retention level of the paraffin remover and preventer in the formation can be determined.

[0115] In order to increase the accuracy of simulating the reservoir formation process, such as Figure 8 As shown, before step 101, the method for testing the retention effect of the paraffin removal and preventative agent provided by the embodiment of the present invention may further include:

[0116] S100: Injecting formation water into the sand filling device through the third injection mechanism.

[0117] The third injection mechanism includes a third pump body 60 , one end of the third pump body 60 is connected to the formation water 50 , and the other end of the third pump body 60 is connected to the sand filling device 10 to inject the formation water 50 into the sand filling device 10 .

[0118] Specifically, the formation water 50 is injected into the sand packing model 10 through the third pump body 60 , and the waxy crude oil in the first intermediate container 202 is injected into the sand packing model 10 through the first pump body 201 , thereby more accurately simulating the reservoir formation process.

[0119] In addition, when simulating the reservoir formation process and the crude oil precipitation process, pressure can be applied to the outlet end 1012 of the sand packing device 10 by the pressure device 80 to simulate the bottom hole flow pressure. For example, the pressure of the back pressure valve 801 can be set to 15 MPa as the bottom hole flow pressure.

[0120] The method for testing the retention effect of a paraffin removal and prevention agent provided in the second embodiment of the present invention comprises injecting waxy crude oil into the sand filling device through a first injection mechanism to simulate the oil reservoir formation process; injecting a paraffin removal and prevention agent into the sand filling device through a second injection mechanism to simulate the process of the paraffin removal and prevention agent entering the formation; connecting the first injection mechanism to the outlet end of the sand filling cavity of the sand filling device, and injecting waxy crude oil into the sand filling device through the first injection mechanism to simulate the process of waxy crude oil precipitation; comparing the components of the simulated output crude oil and the initial crude oil flowing out of the sand filling device to determine the retention degree of the paraffin removal and prevention agent in the formation. Therefore, the embodiment of the present invention can evaluate the paraffin removal and prevention effect of the paraffin removal and prevention agent on waxy crude oil under formation conditions and determine the retention degree of the paraffin removal and prevention agent in the formation.

[0121] In the description of the above embodiments, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the scope of protection of this embodiment.

[0122] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0123] In the description of the present invention specification, it should be understood that the description of the term "some embodiments" or the like means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for testing the retention effect of a wax removal and prevention agent, characterized in that: The sand filling device comprises a sand filling device, a first injection mechanism, a second injection mechanism and a recovery container; the sand filling device has a sand filling chamber with openings at both ends, the sand filling chamber is filled with simulated sand, the first injection mechanism is detachably connected to the inlet end or the outlet end of the sand filling chamber, the second injection mechanism is detachably connected to the inlet end of the sand filling chamber, and the recovery container is detachably connected to the outlet end of the sand filling chamber; The first injection mechanism is used to inject waxy crude oil into the sand filling device to simulate the oil reservoir formation process or crude oil precipitation process; the second injection mechanism is used to inject a wax removal and prevention agent into the sand filling device; the recovery container is used to accommodate simulated produced crude oil flowing out of the sand filling device to compare the simulated produced crude oil with the initial crude oil; The first injection mechanism includes a first pump body and a first intermediate container filled with waxy crude oil, one end of the first intermediate container is connected to the first pump body, and the other end of the first intermediate container is connected to the sand filling device; and The second injection mechanism includes a second pump body and a second intermediate container filled with a wax removal and preventative agent, one end of the second intermediate container is connected to the second pump body, and the other end of the second intermediate container is connected to the sand filling device; The first intermediate container has a first cavity inside, and a first piston that can reciprocate is disposed in the first cavity. The first piston divides the first cavity into a first space and a second space. The first space is connected to the first pump body, and the second space is connected to the sand filling device. The second intermediate container has a second cavity inside, and a second piston that can reciprocate is disposed in the second cavity. The second piston divides the second cavity into a third space and a fourth space. The third space is connected to the second pump body, and the fourth space is connected to the sand filling device. The particle size of the simulated sand filled in the sand filling cavity matches the particle size of the stratum where the simulated oil reservoir is located.

2. The paraffin removal and prevention agent retention effect testing device according to claim 1, characterized in that: An end of the first pump body facing away from the first intermediate container and an end of the second pump body facing away from the second intermediate container are both in communication with formation water.

3. The paraffin removal and prevention agent retention effect testing device according to claim 2, characterized in that: Also includes: The third injection mechanism includes a third pump body, one end of the third pump body is connected to the formation water, and the other end of the third pump body is connected to the sand filling device to inject the formation water into the sand filling device.

4. The paraffin removal and prevention agent retention effect testing device according to claim 3, characterized in that: The first injection mechanism, the second injection mechanism and the third injection mechanism are connected to the sand filling device through a multi-way valve.

5. The wax removal and preventative agent retention effect testing device according to any one of claims 1 to 4, characterized in that: The device further comprises a pressurizing device, which is communicated with the outlet end of the sand filling cavity and is used to apply simulated bottom hole flow pressure to the sand filling cavity.

6. The wax removal and prevention agent retention effect testing device according to claim 5, characterized in that: The pressurizing device includes a back-pressure valve and a hand pump connected to the back-pressure valve, and the hand pump is used to set the pressure for the back-pressure valve.

7. A method for testing the retention effect of a wax removal and prevention agent, applied to the device for testing the retention effect of a wax removal and prevention agent as claimed in any one of claims 1 to 6, characterized in that: include: injecting waxy crude oil into the sand packing device through a first injection mechanism to simulate the oil reservoir formation process; injecting a paraffin remover and preventer into the sand filling device through a second injection mechanism to simulate a process in which the paraffin remover and preventer enters the formation; Connecting the first injection mechanism to the outlet of the sand filling chamber of the sand filling device, and injecting waxy crude oil into the sand filling device through the first injection mechanism to simulate the waxy crude oil precipitation process; The components of the simulated produced crude oil and the initial crude oil flowing out of the sand packing device are compared to determine the retention degree of the paraffin removal and prevention agent in the formation.

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