Underground one-way flow control device and wax washing pipe column

Abstract

The utility model relates to the field of well washing equipment, in particular to an underground one-way flow control device and a wax washing pipe column. The underground one-way flow control device comprises a check valve, the check valve comprises a valve body, a valve element and a valve seat, the valve element and the valve seat are arranged in the valve body, the valve body is provided with an upper connector used for being connected with a hollow sucker rod and a lower connector connected with a sucker rod below, an inlet of the valve body is located in the upper connector, and a valve body outlet of the valve body is formed below the valve seat. The valve element is arranged below the valve seat and above the outlet of the valve body, and a spring is arranged below the valve element in an abutting mode. Well flushing fluid flows into the outlet from the inlet of the check valve from top to bottom, solid particles in the well flushing fluid can be flushed into the oil pipe by the well flushing fluid and finally discharged out of a wellhead from an annular space between the oil pipe and the sucker rod, and one-way circulation paraffin removal of the well flushing fluid is achieved. Therefore, the problem that solid particles in the flushing fluid are easily adhered to the opening of the check valve, so that the check valve fails is solved.

Description

Technical Field

[0001] The utility model relates to the field of well washing equipment, in particular to a downhole one-way flow control device and a wax washing pipe column. Background Art

[0002] During the oil production process, wax is easily deposited periodically inside the oil pipe and on the sucker rod of the oil well, causing the sucker rod to lag and well stuck, affecting the normal production of the oil well. At present, the main method of on-site well washing and unblocking is to use hot water or hot oil to inject through the casing and return the oil pipe. By melting the wax blocks inside the oil pipe and on the sucker rod at high temperature, the load of the oil well can be reduced to ensure the normal production of the oil well.

[0003] Well flushing and jamming have a great impact on oil wells with low formation energy and water-sensitive formations. This is mainly manifested in that the well flushing medium must be in contact with the oil formation. When the well flushing pressure is higher than the formation pressure, the well flushing fluid is easy to enter the formation and react with the formation medium, which will block the channel and cause formation pollution. The oil well recovery time is long or cannot be recovered, which has a great impact on the oil well production. Some low-energy oil wells have a short well flushing cycle, a large well flushing channel space during the well flushing process, a long well flushing cycle time, a large amount of well flushing fluid, and a high cost of pump trucks and tank trucks for each well flushing, which increases the cost of the oil well and reduces the profit contribution value.

[0004] In order to solve the above problems, a Chinese utility model patent with authorization announcement number CN201507281U and authorization announcement date June 16, 2010 discloses a hollow sucker rod well washing device, which includes a hollow sucker rod, a main valve sleeve, a check valve, a main valve body, a hollow sucker rod connector and a solid sucker rod. When in use, the device is installed inside a downhole oil pipe, and the pipe mouth of the downhole oil pipe is installed on a wellhead device, and an oil outlet pipe is provided on the wellhead device. One end of the hollow sucker rod connector is threadedly connected to the hollow sucker rod, and the other end is threadedly connected to one end of the main valve body. One end of the main valve sleeve is threadedly connected to the solid sucker rod, and the other end is threadedly connected to the step in the middle of the other end of the main valve body. The step at the lower part of the main valve body is threadedly connected to the check valve. Four small holes are arranged around the center line at the end of the main valve body, and the small holes are connected to the inner cavity of the main valve sleeve. A radial waist hole is provided in the middle of the main valve body, and a central through hole is provided in the lower part. The lower port of the central through hole is connected to the check valve, and the upper port is connected to the waist hole. When in use, the heated well-washing fluid enters the main valve sleeve through the hollow polished rod, the hollow sucker rod and the four small holes arranged circumferentially on the main valve body in turn, and then is discharged into the downhole oil pipe from the central through hole and the waist hole of the main valve body through the check valve, thereby achieving the purpose of transferring heat energy, dissolving wax and removing scale. Finally, the hollow sucker rod moves up and down to perform work, and the well-washing fluid is continuously discharged from the oil pump, the downhole oil pipe, the wellhead device and the oil outlet pipe to the ground, and enters the ground oil transportation system, so as to achieve the purpose of not polluting the formation.

[0005] Although the hollow sucker rod well washing device provided by the above utility model solves the problem of formation contamination by the well washing fluid medium, during the long-term use of the device, due to the backflow of the well washing fluid through the one-way valve, the inlet of the one-way valve faces downward and the inner diameter of the opening is small, during the long-term use, solid particles in the well washing fluid will be deposited and adhered to the opening of the one-way valve between the opening of the one-way valve and the bottom surface of the valve body, causing its inlet flow channel to become smaller and smaller, and even blocking the valve port of the one-way valve in the later stage, causing the one-way valve to fail, affecting the normal operation of the sucker rod, thereby affecting the production of the oil well and causing unnecessary losses. Utility Model Content

[0006] The utility model aims to provide a downhole one-way flow control device to solve the problem that the opening of the one-way valve in the prior art is easy to adhere to solid particles in the well washing fluid, causing the one-way valve to fail.

[0007] At the same time, the utility model also aims to provide a wax washing pipe string to solve the problem that the normal operation of the pumping rod and the loss of oil well production are affected by the failure of the check valve in the existing wax washing pipe string.

[0008] In order to achieve the above-mentioned purpose, the downhole one-way flow control device of the utility model adopts the following technical solutions:

[0009] A downhole one-way flow control device includes a one-way valve, which includes a valve body, a valve core and a valve seat arranged in the valve body. The valve body is provided with an upper joint for connecting a hollow sucker rod and a lower joint for connecting a lower sucker rod. The valve body inlet is located on the upper joint, the valve body outlet is arranged below the valve seat, the valve core is arranged below the valve seat and above the valve body outlet, and a spring is installed on the top below the valve core.

[0010] Beneficial effects: The downhole one-way flow control device of the utility model is an improved invention. Specifically, by setting the valve body outlet of the one-way valve below its valve seat, the valve core is set below the valve seat and above the valve body outlet, and a spring is installed on the top of the valve core, the well washing fluid enters from the wellhead hollow sucker rod well washing joint, and flows from the one-way valve inlet to the outlet in a top-down manner. The solid particles in the well washing fluid will also be washed into the oil pipe by the well washing fluid, and then flow into the annular space between the oil pipe and the sucker rod through the outlet through-hole, and finally the sucker rod works up and down, and the well washing fluid and its solid particles are continuously discharged from the wellhead from the annular space between the oil pipe and the sucker rod, so as to realize the one-way circulation of the well washing fluid to remove wax. This solves the problem that the opening of the one-way valve is prone to adhere to the solid particles in the well washing fluid, causing the one-way valve to fail.

[0011] Furthermore, the valve body outlet includes more than two through holes arranged around the axis of the valve body.

[0012] Furthermore, the valve seat is annular in shape.

[0013] Furthermore, the inner side surface of the valve seat that cooperates with the valve core is in a conical shape.

[0014] Furthermore, the valve seat is threadably matched with the valve body.

[0015] Furthermore, the valve core is a spherical valve core.

[0016] Furthermore, the spring is a helical compression spring.

[0017] Furthermore, the valve body includes an upper valve body and a lower valve body, and the upper valve body and the lower valve body are threadedly matched.

[0018] Furthermore, the upper joint and the lower joint are adapted to each other.

[0019] The wax washing column of the utility model adopts the following technical scheme:

[0020] A wax washing tubing string comprises a hollow sucker rod and a solid sucker rod, wherein a downhole one-way flow control device is arranged between the hollow sucker rod and the solid sucker rod, and the downhole one-way flow control device comprises a one-way valve, wherein the one-way valve comprises a valve body, a valve core and a valve seat arranged in the valve body, an upper joint for connecting the hollow sucker rod and a lower joint for connecting the lower sucker rod are arranged on the valve body, the valve body inlet is located on the upper joint, the valve body outlet is arranged below the valve seat, the valve core is arranged below the valve seat and above the valve body outlet, and a spring is installed on the top below the valve core.

[0021] Beneficial effects: The wax washing column of the utility model is an improved invention. Specifically, by setting the valve body outlet of the one-way valve of the downhole one-way flow control device below its valve seat, the valve core is set below the valve seat and above the valve body outlet, and a spring is installed on the top of the valve core, the well washing fluid enters from the wellhead hollow sucker rod well washing joint, and flows from the one-way valve inlet to the outlet in a top-down manner. The solid particles in the well washing fluid will also be washed into the oil pipe by the well washing fluid, and then flow into the annular space between the oil pipe and the sucker rod through the outlet through-hole, and finally the sucker rod works up and down, and the well washing fluid and its solid particles are continuously discharged from the annular space between the oil pipe and the sucker rod to the wellhead, so as to realize the one-way circulation of the well washing fluid to clean wax. It effectively solves the problem that the normal operation of the sucker rod and the loss of oil well production are affected by the failure of the one-way valve in the existing wax washing column.

[0022] Furthermore, the valve body outlet includes more than two through holes arranged around the axis of the valve body.

[0023] Furthermore, the valve seat is annular in shape.

[0024] Furthermore, the inner side surface of the valve seat that cooperates with the valve core is in a conical shape.

[0025] Furthermore, the valve seat is threadably matched with the valve body.

[0026] Furthermore, the valve core is a spherical valve core.

[0027] Furthermore, the spring is a helical compression spring.

[0028] Furthermore, the valve body includes an upper valve body and a lower valve body, and the upper valve body and the lower valve body are threadedly matched.

[0029] Furthermore, the upper joint and the lower joint are adapted to each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the check valve of the utility model;

[0031] Figure 2 yes Figure 1 A schematic diagram of the structure of the upper valve body;

[0032] Figure 3 yes Figure 1 A schematic diagram of the structure of the lower valve body;

[0033] Figure 4 It is a schematic diagram of the valve core and valve seat spring connection.

[0034] In the figure: 1, check valve; 101, valve body inlet; 102, valve body outlet; 103, valve body; 104, valve core; 105, valve seat; 106, upper joint; 107, lower joint; 108, cylindrical hole; 109, spring; 110, through hole; 31, upper valve body; 32, lower valve body; 302, upper end of upper valve body; 303, lower end of upper valve body; 202, upper end of lower valve body; 203, lower end of lower valve body. DETAILED DESCRIPTION

[0035] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0036] A hollow sucker rod well washing device with backflow of well washing fluid (flowing from bottom to top) disclosed in the prior art solves the problem of formation contamination by the well washing fluid medium. However, during long-term use of the device, since the well washing fluid flows back through the one-way valve, the inlet of the one-way valve faces downward and the inner diameter of the opening is small, solid particles in the well washing fluid will be deposited and adhered to the opening of the one-way valve between the opening of the one-way valve and the bottom surface of the valve body during long-term use, causing the inlet flow channel to become smaller and smaller, and even blocking the valve port of the one-way valve in the later stage, causing the one-way valve to fail and affecting the normal operation of the sucker rod. In view of the above problems, the utility model designs a downhole one-way flow control device. The core concept of the scheme is to set the valve body outlet of the one-way valve below its valve seat, the valve core below the valve seat and above the valve body outlet, and a spring is installed on the top of the valve core. The well-washing fluid enters from the wellhead hollow sucker rod well-washing joint and flows from the one-way valve inlet to the outlet in a top-down manner. The solid particles in the well-washing fluid will also be flushed into the oil pipe by the well-washing fluid, and then flow into the annular space between the oil pipe and the sucker rod through the outlet through-hole. Finally, the sucker rod works up and down to continuously discharge the well-washing fluid and its solid particles from the annular space between the oil pipe and the sucker rod to the wellhead, so as to realize one-way circulation and wax removal of the well-washing fluid. It can effectively avoid the problem that the one-way valve opening is easy to adhere to the solid particles in the well-washing fluid, causing the one-way valve to fail.

[0037] Based on the above invention concept, Figure 1 As shown, a downhole one-way flow control device of the utility model comprises a one-way valve 1, wherein the one-way valve 1 comprises a valve body 103, a valve core 104 and a valve seat 105 arranged in the valve body 103, the valve body 103 is provided with an upper joint 106 for connecting a hollow sucker rod and a lower joint 107 for connecting a sucker rod below, the valve body inlet 101 is located on the upper joint 106, the valve body outlet 102 of the valve body 103 is arranged below the valve seat 105, the valve core 104 is arranged below the valve seat 105 and above the valve body outlet 102, and a spring 109 is installed on the top below the valve core 104.

[0038] Among the above-mentioned components, the valve body inlet 101 of the one-way valve 1 is arranged to face upward, so that the well-washing fluid can flow through the one-way valve 1 in the downstream direction, and solid particles carried in the well-washing fluid can be prevented from being deposited on the valve body inlet 101. The valve body outlet 102 includes more than two through holes 110 arranged around the axis of the valve body, which can facilitate the well-washing fluid to flow into the oil pipe quickly without depositing solid particles carried in the well-washing fluid there. The number of through holes 110 is not specifically limited, and it is sufficient to ensure that the well-washing fluid passes quickly.

[0039] like Figure 1 In the embodiment shown, the valve body 103 is provided with Figure 2 The upper valve body 31 shown, Figure 3The lower valve body 32 shown, the upper valve body 31 and the lower valve body 32 are preferably connected by threaded connection, which can ensure that the valve body 103 is connected tightly and can also facilitate the disassembly and replacement of its internal components. In some embodiments, the connection method can also be welding or the like.

[0040] like Figure 2 In the embodiment shown, the upper valve body 31 is a hollow cylinder. To connect with the matching hollow sucker rod, the upper end 302 of the upper valve body is provided with an upper joint 106, and the upper joint 106 is provided with an internal thread. The diameter of the upper end 302 of the upper valve body is relatively large. During specific on-site use, the diameter of the hollow cylinder can be determined according to the diameter of the sucker rod to ensure smooth connection. The lower end 303 of the upper valve body is provided with an external thread, and its diameter is smaller than the upper end diameter, which is convenient for the connection of the lower valve body 32. During actual use, the diameter of the lower end 303 of the upper valve body can be adjusted according to the diameter of the valve core 104 without special restrictions. The opening of the lower end 303 of the upper valve body is set to a cone, which can support the lower valve seat 105 to prevent it from loosening. The opening can also be set to other shapes as needed, without special restrictions.

[0041] like Figure 3 In the embodiment shown, the lower end 203 of the lower valve body is provided with a lower joint 107, which is a solid cylinder. The upper end 202 of the lower valve body is provided with a hollow cylinder, which is provided with an internal thread for convenient cooperation with the upper valve body 31, and the lower joint 107 is provided with an external thread. The diameter of the upper end 202 of the lower valve body is larger than the diameter of the lower joint 107. In actual use, the diameter can be flexibly adjusted according to the size of the sucker rod, and no specific limitation is made.

[0042] Since the upper joint 106 and the lower joint 107 are connected to the hollow sucker rod and the solid sucker rod respectively, the upper joint 106 and the lower joint 107 are adapted to each other.

[0043] like Figure 1 and Figure 4 The example shown:

[0044] The valve seat 105 is arranged at the outlet side of the check valve 1. The outer diameter of the valve seat 105 is not larger than the inner diameter of the cylindrical hole 108, which can ensure that it can be smoothly installed in the cylindrical hole 108 provided in the middle of the valve body 31. Its shape is set to an annular shape, which can facilitate the fixing of the position of the valve core 104. In some other embodiments, the shape of the valve seat 105 can also be set to a conical shape. Its inner side surface is preferably conical, which can fit tightly with the valve core 104 and prevent oil from entering and blocking the cylindrical hole 108. In some other embodiments, its inner side surface can also be set to a cylindrical or cube shape. The valve seat 105 is provided with an external thread, which can be matched with the thread of the valve body 103 and will not fall off. In some other embodiments, the valve seat 105 can also be welded to the valve body 31. Since the well washing fluid contains more chemical substances, the valve seat 105 is preferably made of a corrosion-resistant steel ring. In some embodiments, the material of the valve seat 105 can also be selected from other corrosion-resistant materials.

[0045] The valve core 104 is arranged below the outlet of the valve seat 105 and above the outlet 102 of the valve body. To better cooperate with the cylindrical hole 108, the shape of the valve core 104 is preferably spherical. In some embodiments, it can also be set to a conical shape. The valve core 104 is preferably made of a corrosion-resistant carbon steel material. In some embodiments, the material of the valve core 104 can also be selected from other corrosion-resistant materials. In order to smoothly install the valve core 104 in the cylindrical hole 108, the diameter of the valve core 104 must be smaller than the inner diameter of the cylindrical hole 108.

[0046] A spring 109 is installed at the top of the valve core 104, which is a spiral compression spring. Figure 3 In the embodiment shown, a rectangular cross-section compression spring is preferred. In some embodiments, a circular cross-section compression spring or a tower-shaped compression spring may also be selected. The spring 109 can help maintain the switching state of the check valve 1. The well washing fluid will push open the valve core 104 under a certain pressure, allowing the well washing fluid to enter the annular space between the oil pipe and the sucker rod from the hollow sucker rod. If the annular space channel pressure is higher than the hollow sucker rod pressure, the valve core 104 returns to its original position, the check valve 1 is closed, and the mixed medium cannot enter the hollow sucker rod, thereby ensuring that the well washing channel is unobstructed.

[0047] All joints of the device should be sealed and tightened according to operating specifications. In specific use, sealing devices such as sealing rings can be used.

[0048] When using the device, first assemble it on the ground, install the spring 109 and the valve core 104 in the cylindrical hole 108 in sequence, then thread the valve seat 105 with the valve body 103, then thread the upper valve body 31 with the lower valve body 32, and then connect the assembled check valve 1 during the operation of lowering the pipe string. Figure 2 The upper joint 106 at one end of the middle upper valve body 31 is threadedly connected to the hollow sucker rod. Figure 3The thread of the lower joint 107 at the lower end of the middle and lower valve body 203 is connected to the thread of the solid sucker rod, and its sealing and tightening requirements are guaranteed according to the operating specifications. After the installation is completed, water is introduced into the oil pipe for pressure testing. The hollow sucker rod inlet is leak-free and qualified. After the installation is completed, a new well-washing channel is established. The well-washing fluid enters from the well-washing joint of the hollow sucker rod at the wellhead, and flows into the annular space between the oil pipe and the sucker rod through the hollow sucker rod, the check valve 1, and the solid sucker rod. During the well-washing process, the control device controls the flow direction of the well-washing medium through the valve core 104. The well-washing fluid pushes open the valve core 104 under a certain pressure, so that the well-washing medium enters the annular space between the oil pipe and the sucker rod from the hollow sucker rod. If the pressure of the annular space channel is higher than the pressure of the hollow sucker rod, the valve core 104 returns to its position, the control device is closed, and the mixed medium cannot enter the hollow sucker rod, thereby ensuring that the well-washing channel is unobstructed. Finally, the sucker rod works up and down to continuously discharge the well-washing fluid from the annular space between the oil pipe and the sucker rod to the wellhead, thereby realizing the one-way circulation of the well-washing fluid to remove wax.

[0049] The specific implementation of the wax washing column of the utility model is as follows:

[0050] The innovation of the wax washing pipe column of the utility model lies in the adoption of the downhole one-way flow control device of the utility model, and the other structures are all existing technologies. The structure of the downhole one-way flow control device can refer to the specific implementation method of the downhole one-way flow control device mentioned above, which will not be repeated here.

Claims

1. A downhole one-way flow control device, comprising a one-way valve, the one-way valve comprising a valve body, a valve core and a valve seat arranged in the valve body, the valve body is provided with an upper joint for connecting a hollow sucker rod and a lower joint for connecting a lower sucker rod, the valve body inlet is located on the upper joint, and is characterized in that: The valve body outlet of the valve body is arranged below the valve seat, the valve core is arranged below the valve seat and above the valve body outlet, and a spring is installed on the top of the valve core below.

2. The downhole one-way flow control device according to claim 1, characterized in that: The valve body outlet includes two or more through holes arranged around the axis of the valve body.

3. The downhole one-way flow control device according to claim 1, characterized in that: The valve seat is annular in shape.

4. The downhole one-way flow control device according to claim 3, characterized in that: The inner side surface of the valve seat matched with the valve core is in a conical shape.

5. The downhole one-way flow control device according to any one of claims 1 to 4, characterized in that: The valve seat is threadably matched with the valve body.

6. The downhole one-way flow control device according to any one of claims 1 to 4, characterized in that: The valve core is a spherical valve core.

7. The downhole one-way flow control device according to any one of claims 1 to 4, characterized in that: The spring is a helical compression spring.

8. The downhole one-way flow control device according to claim 1, characterized in that: The valve body comprises an upper valve body and a lower valve body, and the upper valve body and the lower valve body are threadedly matched.

9. The downhole one-way flow control device according to claim 1, characterized in that: The upper joint and the lower joint are adapted to each other.

10. A wax washing pipe string, including a hollow sucker rod and a solid sucker rod, characterized in that: A downhole one-way flow control device according to any one of claims 1 to 9 is arranged between the hollow sucker rod and the solid sucker rod.

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