A de-waxing stick

Abstract

The utility model provides a kind of wax removal stick belongs to the technical field of preventing or limiting paraffin or similar substance deposition by chemical method.Wax removal stick includes the stick body for being thrown into gas production well to dissolve paraffin on the inner wall of oil pipe, stick body is cylindrical, through hole is set on stick body along the axial through stick body, through hole constitutes the exhaust passage for natural gas in gas production well to discharge upwards.Wax removal stick is thrown into gas production well to carry out wax removal, and natural gas can discharge upwards by through hole on stick body, does not affect gas production operation, so it is unnecessary to stop production, realizes side gas production, side wax removal, and does not affect production efficiency.

Description

Technical Field

[0001] This utility model relates to a wax removal rod, belonging to the technical field of preventing or limiting the deposition of paraffin or similar substances by chemical methods. Background Technology

[0002] Most condensate gas reservoirs precipitate wax during the extraction process. This wax deposits on the inner wall of the tubing, causing blockage and obstructing the gas well's production, thus affecting the well's productivity and even preventing it from being opened for production.

[0003] Existing wax removal technologies mainly include mechanical wax removal, electric heating technology, hot washing wax removal, and chemical wax removal. Among them, mechanical wax removal relies on wax scrapers or pipe cleaners, and the wax removal devices are prone to wear or jamming, requiring frequent replacement or maintenance, which increases operation time and labor costs. Electric heating (such as skin effect heating rods) wax removal requires continuous power supply, consumes a lot of electricity, and has high initial investment and maintenance costs, limiting its application in low-production wells. Hot washing wax removal relies on boiler trucks to heat steam or hot fluids, which has the problems of large heat loss and high energy consumption. Of the heat conducted longitudinally and laterally in the wellbore by the hot washing fluid, more than 50% is lost to the casing or environment, especially in winter, when the tubing needs to be repeatedly preheated, further increasing fuel consumption.

[0004] Chemical dewaxing is widely used in oilfields due to its ease of operation. There are two forms of chemical dewaxing: liquid dewaxing agents and solid dewaxing rods. Liquid dewaxing agents flow quickly through the wax-collecting area, resulting in a short interaction time with the wax and limited dewaxing effectiveness. Chinese utility model patent CN2921271Y discloses an active metal dewaxing and unblocking rod for oil wells. This rod is made of an active metal with a circular cross-section and at least one end has a guide structure. After being inserted into the well, it guides the rod downwards smoothly. When the rod reaches the wax-collected area in the tubing, it encounters resistance and begins a chemical reaction with the water in the well fluid. The resulting heat melts the paraffin wax, thus clearing the blockage. The rod melts as it descends, achieving the purpose of dewaxing and unblocking. When the well's produced fluid does not contain water, an appropriate amount of water needs to be added through the blowout preventer after inserting the dewaxing rod.

[0005] If the aforementioned wax-removing rods are used in gas production wells, they will melt on their own after being inserted into the well due to the moisture content in the natural gas and the high temperature downhole. However, because the wax-removing rods are solid rods with an outer diameter slightly smaller than the inner diameter of the tubing, they themselves become "blockages" after being inserted into the well, preventing the natural gas from flowing out smoothly. Therefore, production must be stopped for wax removal, and normal production can only resume after the wax removal is completed, which significantly affects production efficiency. Utility Model Content

[0006] The purpose of this utility model is to provide a wax removal rod to solve the problem that when existing wax removal rods are put into gas wells, natural gas cannot be discharged smoothly, and production must be stopped for wax removal operations, which affects production efficiency.

[0007] To achieve the above objectives, the wax removal rod of this utility model adopts the following technical solution:

[0008] A wax removal rod includes a rod body for being inserted into a gas well to dissolve wax deposits on the inner wall of an oil pipe. The rod body is cylindrical and has a through hole running through the rod body along the axial direction. The through hole forms an exhaust channel for natural gas in the gas well to be discharged upwards.

[0009] The beneficial effects of the above technical solution are as follows: This utility model is an improved invention. The improvement is that the rod body is provided with a through hole that runs through the rod body along the axial direction. The through hole forms an exhaust channel for natural gas in the gas well to be discharged upward. In this way, while the wax removal rod is put into the gas well for wax removal, natural gas can be discharged upward through the through hole on the rod body without affecting the gas production operation. Therefore, there is no need to stop production, and gas production and wax removal can be carried out at the same time without affecting production efficiency.

[0010] Furthermore, the through hole is a cylindrical hole.

[0011] Furthermore, there is only one through hole, and the axis of the through hole is coaxial with the axis of the rod.

[0012] Furthermore, if the inner diameter of the through hole is defined as D1, then 15mm≤D1≤0.7D2, where D2 is the outer diameter of the rod.

[0013] Furthermore, 15mm≤D1≤0.45D2.

[0014] Furthermore, let the outer diameter of the rod be defined as D2, then D2 = (D - 2) mm, where D is the inner diameter of the oil pipe.

[0015] Furthermore, if we define the length of the rod as L, then 35mm ≤ L ≤ 50mm.

[0016] Furthermore, at least one end of the rod is chamfered.

[0017] Furthermore, the through holes include a central through hole coaxial with the axis of the rod body and three or more peripheral through holes arranged at equal intervals around the central through hole.

[0018] Furthermore, there are three or more through holes, which are arranged at equal intervals around the axis of the rod. Attached Figure Description

[0019] Figure 1 This is a perspective view of Embodiment 1 of the wax removal rod of this utility model;

[0020] Figure 2This is a side view of Embodiment 1 of the wax removal rod of this utility model;

[0021] Figure 3 This is a front view of Embodiment 1 of the wax removal rod of this utility model;

[0022] Figure 4 This is a perspective view of Embodiment 2 of the wax removal rod of this utility model;

[0023] Figure 5 This is a perspective view of Embodiment 3 of the wax removal rod of this utility model;

[0024] Figure 6 This is a perspective view of Embodiment 4 of the present invention's wax removal rod;

[0025] Figure 7 This is a perspective view of Embodiment 5 of the present invention's wax removal rod;

[0026] Figure 8 This is a schematic diagram of the existing wellhead gas production tree.

[0027] In the diagram: 1. Rod body; 2. Through hole; 21. Central through hole; 22. Peripheral through hole; 3. Chamfer; 4. First valve; 5. Second valve; 6. Third valve. Detailed Implementation

[0028] To address the technical problems existing in the prior art, the basic concept of this utility model is to set a through hole through the rod body of the wax removal rod. The through hole forms an exhaust channel for natural gas in the gas well to be discharged upwards. In this way, wax removal and gas extraction operations can be carried out at the same time without affecting production.

[0029] The features and performance of this utility model will be further described in detail below with reference to the embodiments.

[0030] The implementation method of the wax rod in this utility model:

[0031] like Figure 1 , Figure 2 and Figure 3 As shown, the wax-removing rod includes a rod body 1 for use in gas wells to dissolve wax deposits on the inner wall of the tubing. The specific composition of the rod body 1 is prior art and can be the same as the composition of the active metal wax-removing and unblocking rod disclosed in CN2921271Y, or the same as the composition of the rod-shaped solid unblocking agent disclosed in CN117126654A, or other wax-removing components in the prior art that can be made into a solid wax-removing rod. This utility model does not impose any restrictions.

[0032] The rod body 1 is cylindrical, allowing it to fit into the inner diameter of the tubing and facilitate its smooth downward movement within the tubing under its own weight. The rod body 1 has an axially penetrating through-hole 2, which forms an exhaust channel for the natural gas in the gas well to be discharged upwards. Thus, while the rod is removing wax, natural gas can be discharged upwards through the through-hole 2 on the rod body 1 without affecting gas production operations. Therefore, production can be carried out simultaneously without stopping production, achieving simultaneous gas production and wax removal without impacting production efficiency.

[0033] As an example 1, the through hole 2 in this embodiment is a cylindrical hole, which is easy to form. The hole wall of through hole 2 has a smooth transition without sharp corners, making it less prone to cracking and resulting in good overall structural strength. Furthermore, there is only one through hole 2, and the axis of this through hole 2 is coaxial with the axis of the rod body 1, meaning the rod body 1 is a hollow cylinder. This not only simplifies the structure and facilitates forming, but also, in practical applications, the melting process of the wax-removing rod itself proceeds from the outside to the inside, meaning the outer diameter of the rod body 1 gradually decreases. If the rod body 1 were a solid cylinder, when the outer diameter is less than a certain level, it would directly fall through the wax layer to the bottom of the well, resulting in wasted wax-removing rods. In practical applications, a relatively large number of wax-removing rods are needed to achieve the desired wax-removing effect, leading to higher wax-removing costs. The hollow rod body 1, however, maximizes utilization, reduces waste of wax-removing rods, and lowers wax-removing costs.

[0034] Furthermore, such as Figure 2 As shown, the inner diameter of the through-hole 2 is defined as D1, and the outer diameter of the rod 1 is defined as D2. Therefore, 15mm ≤ D1 ≤ 0.7D2. In this embodiment, the lower limit of D1 is designed to be 15mm, considering that the maximum adjustment diameter of the current ground-based throttle nozzle (a device used to regulate natural gas flow) is 15mm. Therefore, the inner diameter of the through-hole 2 cannot be less than 15mm; otherwise, the through-hole 2 would become an obstruction, essentially a necking position, affecting the flowing natural gas and thus the flow regulation effect of the ground-based throttle nozzle. Therefore, 15mm ≤ D1 ensures that the inner diameter of the through-hole 2 is larger than the maximum adjustment diameter of the ground-based throttle nozzle, thus avoiding any impact on the flow regulation effect of the ground-based throttle nozzle.

[0035] In this embodiment, the upper limit of D1 is set at 0.7D2. This is because if the inner diameter of the through hole 2 is too large, the wall thickness of the rod 1 will be too thin. On the one hand, this would make it difficult to form and manufacture, and even if it is manufactured, the structural strength would be relatively low, making it easy to break. On the other hand, if the material of the rod 1 is too small, it will melt away quickly, requiring a large number of wax-removing rods to achieve the desired effect, which would be cumbersome. Therefore, considering the structural strength of the wax-removing rod, the number of wax-removing rods required, and the waste of wax-removing rods, a more preferable range is 15mm≤D1≤0.45D2, that is, the upper limit of D1 is set at 0.45D2.

[0036] Of course, in other embodiments, depending on the actual adjustment diameter of the ground throttle nozzle, the lower limit of D1 can also be 16mm, 17mm, 18mm, 19mm, 20mm, or a larger value. Of course, depending on the specific manufacturing process and the specific composition of the dewaxing rod, provided the structural strength is sufficient, the upper limit of D1 can also be greater than 0.7D2, for example, 0.71D2, 0.72D2, 0.73D2, 0.74D2, or 0.75D2. Of course, depending on the specific wax deposition in the tubing, if the wax deposition is large and a heavier dewaxing rod is required, a more favorable upper limit of D1 could be 0.4D2, 0.35D2, or 0.3D2; if the wax deposition is small, to avoid material waste, a more favorable upper limit of D1 could be 0.5D2, 0.55D2, 0.6D2, or 0.65D2.

[0037] In this embodiment, the outer diameter D2 of rod 1 is (D-2) mm, where D is the inner diameter of the tubing. For a conventional 2 3 / 8" gas production tubing string, the outer diameter of the tubing is 60.3 mm and the inner diameter is 50.3 mm. Therefore, the outer diameter D2 of rod 1 is 48.3 mm. This creates a 1 mm gap between rod 1 and the inner wall of the tubing. This facilitates the smooth descent of rod 1, prevents it from getting stuck, and allows it to stop when encountering a wax layer, preventing the rod from passing directly through the wax layer with a small diameter, which would result in a certain thickness of wax layer not being dissolved.

[0038] Of course, in other embodiments, if the surface roughness of the rod 1 is poor and prone to jamming, D2 can be set to (D-2.5) mm, (D-3) mm, or (D-3.5) mm to appropriately increase the gap between the rod 1 and the inner wall of the tubing. In other embodiments, if the surface roughness of the rod 1 is good and the downward movement is smooth, D2 can be set to (D-1.9) mm or (D-1.8) mm to further reduce the gap between the rod 1 and the inner wall of the tubing, thereby improving the effect of removing the wax layer.

[0039] like Figure 3 As shown, the length of rod 1 is defined as L, then 35mm ≤ L ≤ 50mm. The lower limit of L is set to 35mm to take into account... Figure 8 As shown, the existing wellhead gas production tree has a first valve 4, a second valve 5, and a third valve 6 arranged vertically from top to bottom. When inserting the dewaxing rod, open the first valve 4 and the second valve 5, close the third valve 6, insert the dewaxing rod from the top of the gas production tree, close the first valve 4, and open the third valve 6. The dewaxing rod will then fall into the gas production well under its own weight. Repeat the above steps when multiple dewaxing rods need to be inserted.

[0040] The second valve 5 is always open and has two channels (the specific structure of the second valve 5 is prior art and will not be described in this utility model). In order to prevent the wax removal rod from falling into other channels and not being able to fall on the third valve 6, the length of the rod body 1 is designed to be greater than the length of the second valve 5, so as to ensure that the rod body 1 can pass through the second valve 5 in a vertical position.

[0041] The upper limit of L is set at 50mm. Firstly, this takes into account the distance between the first valve 4 and the third valve 6; the length of rod 1 cannot exceed the distance between the two valves, otherwise it cannot be inserted. Secondly, if the length of rod 1 is too large, it will slowly melt after being inserted into the well due to the temperature and moisture carried by the natural gas. If the initial wax layer is small, a large amount of melted wax will be wasted. Furthermore, when it falls to the lower wax layer, the outer diameter of the rod has decreased, and it may directly pass through the wax layer and fall to the bottom of the well, resulting in material waste. Therefore, the length of rod 1 should always be sufficient, and multiple insertions can be used to ensure the wax removal effect.

[0042] The specific length of the rod 1 can be 35mm, 40mm, 45mm or 50mm. In other embodiments, if there is no second valve 5 or the second valve 5 has no other channel, the length of the rod 1 can be reduced, for example to 34mm, 33mm, 32mm, 31mm or 30mm. Of course, if the distance between the first valve 4 and the third valve 6 is large enough, the length of the rod 1 can also be appropriately increased, for example to 55mm or 60mm.

[0043] Given that the length L of rod 1, the outer diameter D2, and the inner diameter D1 of the through hole are fixed, the volume of the wax removal rod is L × {π(D2 / 2)}. 2 -π(D1 / 2) 2 The number of dewaxing rods is mainly calculated based on the effective components of the liquid dewaxing agent. By converting the effective concentration, the required amount of dewaxing agent can be converted into the number of hollow dewaxing rods to be used.

[0044] In addition, in this embodiment, a chamfer 3 is provided at one end of the rod 1. When betting, the chamfer 3 is facing down, which can play a guiding role and make the downward movement of the rod 1 smoother.

[0045] Example 2 of the wax rod in this utility model:

[0046] like Figure 4 As shown, the difference from Embodiment 1 is that in this embodiment, chamfers 3 are provided at both ends of the rod 1. The advantage of this setting is that when casting the wax removal rod, there is no need to distinguish between the upper and lower ends; either end can be facing down.

[0047] Example 3 of the wax rod in this utility model:

[0048] like Figure 5 As shown, the difference from Embodiment 1 is that neither end of the rod 1 in this embodiment is chamfered. In this case, the outer diameter of the dewaxing rod needs to be controlled, and the downward movement of the dewaxing rod can only be achieved by relying on the gap between the dewaxing rod and the inner wall of the oil pipe.

[0049] Example 4 of the present invention: The wax rod is used in this invention.

[0050] like Figure 6 As shown, the difference from Embodiment 1 is that the through hole 2 in this embodiment is a square hole.

[0051] Example 5 of the wax rod in this utility model:

[0052] like Figure 7 As shown, the through hole in this embodiment includes a central through hole 21 coaxial with the axis of the rod 1 and six peripheral through holes 22 arranged at equal intervals around the central through hole 21. At this time, the central through hole 21 and the six peripheral through holes 22 all form exhaust channels.

[0053] In other embodiments of the wax removal rod: Unlike embodiment 5, only three peripheral through holes are provided and are arranged at equal intervals around the central through hole. In this case, the central through hole and the three peripheral through holes form an exhaust channel. In other embodiments, four or five peripheral through holes can also be provided, or more, such as seven or more, depending on the inner diameter of the through hole itself and the outer diameter of the rod.

[0054] In other embodiments of the wax removal rod: there are three or more through holes arranged at equal intervals around the axis of the rod body, specifically three, four, five, six or more, which is equivalent to no longer setting a central through hole, only peripheral through holes, and each peripheral through hole forms an exhaust channel.

[0055] In other embodiments of the wax removal rod: In embodiments with chamfers, the chamfers can also be replaced with rounded corners.

[0056] In other embodiments of the wax removal rod: when the axis of the through hole is coaxial with the axis of the rod body, the through hole can also be a tapered hole.

[0057] In other embodiments of the wax removal rod: when the through hole is not a cylindrical hole, it can be a hexagonal hole, or of course, an elliptical hole.

[0058] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. The patent protection scope of the present utility model shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present utility model shall also be included within the protection scope of the present utility model.

Claims

1. A wax-removing rod, comprising a rod body for insertion into a gas well to dissolve wax deposits on the inner wall of a tubing, the rod body being cylindrical, characterized in that, The rod body is provided with a through hole that runs through the rod body along the axial direction. The through hole forms an exhaust channel for natural gas in the gas well to be discharged upwards.

2. The wax removal rod according to claim 1, characterized in that, The through hole is a cylindrical hole.

3. The wax removal rod according to claim 2, characterized in that, There is only one through hole, and the axis of the through hole is coaxial with the axis of the rod.

4. The wax removal rod according to claim 3, characterized in that, If the inner diameter of the through hole is defined as D1, then 15mm≤D1≤0.7D2, where D2 is the outer diameter of the rod.

5. The wax removal rod according to claim 4, characterized in that, 15mm≤D1≤0.45D2.

6. The wax-removing rod according to any one of claims 1 to 5, characterized in that, Define the outer diameter of the rod as D2, then D2 = (D - 2) mm, where D is the inner diameter of the oil pipe.

7. The wax-removing rod according to any one of claims 1 to 5, characterized in that, If the length of the rod is defined as L, then 35mm ≤ L ≤ 50mm.

8. The wax-removing rod according to any one of claims 1 to 4, characterized in that, At least one end of the rod is chamfered.

9. The wax removal rod according to claim 2, characterized in that, The through holes include a central through hole coaxial with the axis of the rod and three or more peripheral through holes arranged at equal intervals around the central through hole.

10. The wax-removing rod according to claim 2, characterized in that, There are three or more through holes, which are arranged at equal intervals around the axis of the rod.

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