An oil return device

Abstract

This invention discloses an oil return device, belonging to the field of petroleum extraction technology. It includes a base plate and an inner cylinder, a first outer cylinder, and a second outer cylinder sequentially nested from the inside out on the base plate. The base plate is fixedly connected to the wellhead. A first return fluid chamber, a second return fluid chamber, and a third return fluid chamber are sequentially formed between the inner cylinder, the first outer cylinder, and the second outer cylinder. Oil carried out by the tubing through the wellhead enters the first and second return fluid chambers and then flows into the third return fluid chamber through an overflow pipe. An axial spiral guide vane is installed in the second return fluid chamber, and a radial spiral guide vane is installed in the third return fluid chamber. During oil return, the swirling flow direction formed in the second and third return fluid chambers is the same as that formed in the third return fluid chamber. The swirling oil flows back into the wellhead from the first return fluid chamber. This invention can create swirling flow in the second and third return fluid chambers, smoothly returning the oil carried out by the tubing to the wellhead without the need for further processing of the temporarily stored oil, thus achieving convenient operation.

Description

Technical Field

[0001] This invention relates to the field of oil extraction technology, and in particular to an oil reflux device. Background Technology

[0002] During wellhead operations, the pulled-out tubing carries crude oil and wastewater adhering to its surface to the ground, polluting the well site environment and wasting crude oil. To avoid environmental pollution and economic losses from crude oil waste, existing technologies typically employ collection devices to collect the crude oil. Once the collection device is full or no more crude oil is overflowing, the crude oil within is then processed. However, the reprocessing and transportation of crude oil within the collection device is quite difficult.

[0003] Chinese patent CN200943472Y discloses an oil well overflow recovery device, which includes an oil-water receiving tray and an oil-water tank. Crude oil and wastewater from the tubing fall into the oil-water receiving tray and flow into the oil-water tank for recovery. The oil-water tank has an oil-water outlet for exporting and processing the oil and water. This solution only collects the oil and water using the tank; further processing is still required, making its application somewhat inconvenient.

[0004] Chinese patent application CN104632144A discloses a liquid collection device, comprising a distributor fan, collection pool a, collection pool b, a grid, a guide channel, and a U-shaped locking groove. The distributor fan is fixed to the surface casing head via a sealing gasket and a locking ring. Collection pools a and b are connected to the outer end of the surface casing head, and the U-shaped locking groove secures them. The grid covers the corresponding positions of collection pools a and b, and the guide channel is connected and fixed to the drain ports of collection pools a and b. When crude oil overflows during wellhead operations, this liquid collection device can recover the overflowed crude oil, avoiding environmental pollution and economic losses caused by crude oil waste. However, this solution only uses collection pools to collect crude oil and lacks a process for subsequent processing.

[0005] As can be seen from the above, the existing technical solutions basically involve collecting the oil and water first, and then processing the collected oil and water. Currently, there is no suitable device that can more easily recover crude oil. Summary of the Invention

[0006] The purpose of this invention is to provide an oil return device to solve the problems existing in the prior art. By setting an inner cylinder that connects to the wellhead, and installing a first outer cylinder and a second outer cylinder outside the inner cylinder, a first return chamber, a second return chamber, and a third return chamber for oil return can be formed. Under the action of axial spiral guide vanes and radial guide vanes, the oil forms a swirling flow, which can smoothly return the oil carried out by the tubing to the wellhead without the need for reprocessing of the temporarily stored oil, thus improving the convenience of operation.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] This invention provides an oil return device, comprising a base plate and an inner cylinder, a first outer cylinder, and a second outer cylinder sequentially nested from the inside out on the base plate. The base plate is fixedly connected to a wellhead. A first return fluid chamber communicating with the wellhead is formed inside the inner cylinder. A second return fluid chamber communicating with the first return fluid chamber is formed between the inner cylinder and the first outer cylinder. A third return fluid chamber communicating with the second return fluid chamber is formed between the first outer cylinder and the second outer cylinder. Oil carried out by the tubing through the wellhead enters the first and second return fluid chambers and then enters the third return fluid chamber through an overflow pipe. An axial spiral guide vane is provided in the second return fluid chamber, and a radial spiral guide vane is provided in the third return fluid chamber. During oil return, the swirling direction formed in the second and third return fluid chambers is the same as the swirling direction formed in the third return fluid chamber. The oil forming the swirling flow flows back from the first return fluid chamber to the wellhead.

[0009] Preferably, a collection groove is provided at the top of the first outer cylinder, and the diameter of the collection groove is larger than the diameter of the first outer cylinder.

[0010] Preferably, the inlet of the overflow pipe is installed tangentially on the collection tank, and the swirling flow formed in the second return chamber is directed toward the inlet of the overflow pipe.

[0011] Preferably, the outlet of the overflow pipe is installed tangentially on the second outer cylinder, and the outlet of the overflow pipe faces the swirling direction formed in the third return liquid chamber.

[0012] Preferably, a telescopic corrugated pipe is installed on the top of the collection tank, and the diameter of the telescopic corrugated pipe is the same as the large opening diameter of the collection tank.

[0013] Preferably, the height of the first outer cylinder is greater than the height of the second outer cylinder, the diameter of the second outer cylinder is greater than the diameter of the collection tank, and a perforated plate is installed on the top of the third return chamber.

[0014] Preferably, an oil scraper ring is installed on the top of the inner cylinder. The oil scraper ring is made of flexible material, and its inner diameter in its undeformed state is less than or equal to the outer diameter of the oil pipe.

[0015] Preferably, an oil baffle is installed on the top of the inner cylinder, the outer diameter of the oil baffle is between the diameter of the inner cylinder and the diameter of the first outer cylinder, the oil baffle is installed on the top of the inner cylinder by a support column, a through hole is provided in the middle of the oil baffle to penetrate the oil pipe, and the oil scraper ring is concentric with the through hole and is installed on the oil baffle.

[0016] Preferably, the bottom of the first outer cylinder is provided with a first return port that connects the second return chamber and the third return chamber, an inwardly opening baffle is provided on the inner side of the first return port, and a tangential guide plate is provided on the outer side of the first return port.

[0017] Preferably, the bottom of the inner cylinder is provided with a second return port that connects the first return chamber and the second return chamber, and the second return port is evenly distributed along the circumference.

[0018] The present invention achieves the following technical effects compared to the prior art:

[0019] (1) By setting an inner cylinder that connects to the wellhead and installing a first outer cylinder and a second outer cylinder on the inner cylinder, the present invention can form a first return fluid chamber, a second return fluid chamber and a third return fluid chamber for oil return. Under the action of the axial spiral guide vanes and the radial guide vanes, the oil forms a swirling flow, which can smoothly return the oil carried out by the tubing to the wellhead without having to reprocess the temporarily stored oil, thus improving the convenience of operation.

[0020] (2) The inlet of the overflow pipe of the present invention is installed on the collection tank along the tangential direction of the collection tank, and the outlet of the overflow pipe is installed on the second outer cylinder along the tangential direction of the second outer cylinder. When the oil and water in the collection tank overflow, they can enter the overflow pipe more effectively by means of the swirling flow formed in the second return liquid chamber. At the same time, the liquid flow entering the third return liquid chamber follows the swirling flow formed in the third return liquid chamber, further improving the swirling effect, improving the fluidity of the oil, and facilitating the return of the oil.

[0021] (3) The top of the collection tank of the present invention is equipped with a telescopic corrugated pipe. The diameter of the telescopic corrugated pipe is the same as the large diameter of the collection tank. Since oil may splash when the oil pipe is pulled out, the height of the collection tank can be increased by stretching the corrugated pipe to block the splashed oil, thereby avoiding environmental pollution and waste caused by oil splashing. When the oil stops splashing, the height of the corrugated pipe is compressed to facilitate operation inside the collection tank.

[0022] (4) The present invention has an oil baffle plate installed at the top of the inner cylinder. The oil baffle plate can form a support for the oil scraping ring and realize the scraping of oil from the outer wall of the oil pipe. Since the oil baffle plate is installed at the top of the inner cylinder through the support column, it can not only block the oil from spraying from the wellhead to a certain extent, but also guide the blocked part of the oil through the gap between the oil baffle plate and the inner cylinder to the second return fluid chamber, and guide the sprayed oil through the upper surface of the oil baffle plate to the second return fluid chamber. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 for Figure 1 Cross-sectional view;

[0026] Figure 3 The top view of the axial helical guide vane and the radial helical guide vane is shown for the present invention;

[0027] Figure 4 This is a schematic diagram of the internal structure of the second outer cylinder of the present invention;

[0028] Figure 5 This is a schematic diagram of the external structure of the inner cylinder of the present invention;

[0029] Figure 6 This is a schematic diagram of the oil scraper ring structure of the present invention;

[0030] The components are as follows: 1. Second outer cylinder; 2. First outer cylinder; 3. Collection trough; 4. Corrugated pipe; 5. Oil pipe; 6. Oil scraper ring; 7. Oil baffle; 8. Overflow pipe; 9. Hollowed-out plate; 10. Wellhead; 11. Inner cylinder; 12. Bottom plate; 13. Radial spiral guide vane; 14. Axial spiral guide vane; 15. Tangential guide plate; 16. Inwardly open baffle; 17. First return port; 18. Second return port; 19. Support column; 20. Clamp. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The purpose of this invention is to provide an oil return device to solve the problems existing in the prior art. By setting an inner cylinder that connects to the wellhead, and then installing a first outer cylinder and a second outer cylinder around the inner cylinder, a first return chamber, a second return chamber, and a third return chamber for oil return can be formed. Under the action of axial spiral guide vanes and radial guide vanes, the oil forms a swirling flow, which can smoothly return the oil carried out of the tubing to the wellhead without the need for reprocessing of the temporarily stored oil, thus improving the convenience of operation.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] like Figures 1-6As shown, the present invention provides an oil return device, including a base plate 12 and an inner cylinder 11, a first outer cylinder 2, and a second outer cylinder 1 sequentially sleeved from the inside to the outside on the base plate 12. The base plate 12 is fixedly connected to the wellhead 10, and the connection can be made via a flange. A first return fluid chamber is formed inside the inner cylinder 11, communicating with the wellhead 10. An oil pipe 5 can extend from the wellhead 10, pass through the first return fluid chamber, and extend out of the first return fluid chamber. A second return fluid chamber is formed between the inner cylinder 11 and the first outer cylinder 2, communicating with the first return fluid chamber. When the oil pipe 5 carries out oil, the oil can enter the first return fluid chamber or enter the second return fluid chamber from the top of the inner cylinder 11, and can flow through the through-port (second return fluid port 18) between the first and second return fluid chambers. A third return fluid chamber, connected to the second return fluid chamber, is formed between the first outer cylinder 2 and the second outer cylinder 1. This third return fluid chamber primarily receives oil overflowing from the first and second return fluid chambers, thus forming a three-stage oil temporary storage space. Oil carried out by the tubing 5 through the wellhead 10 enters the first and second return fluid chambers and then flows into the third return fluid chamber through the overflow pipe 8. During reflux, it returns to the wellhead 10 through the first return fluid port 17. The second return fluid chamber is equipped with several axial spiral guide vanes 14, which create an axially downward swirling flow during oil reflux. The third return fluid chamber is equipped with several radial spiral guide vanes 13, which create a radially centripetal swirling flow during oil reflux. Furthermore, during oil reflux, the swirling flow direction formed in the second reflux chamber is the same as that formed in the third reflux chamber. The oil forming the swirling flow converges in the second reflux chamber and then enters the first reflux chamber, from which it flows back into the wellhead 10. In summary, by setting an inner cylinder 11 that connects to the wellhead 10, and by installing a first outer cylinder 2 and a second outer cylinder 1 around the inner cylinder 11, the present invention can form a first reflux chamber, a second reflux chamber, and a third reflux chamber for oil reflux. Under the action of the axial spiral guide vane 14 and the radial spiral guide vane 13, the oil forms a swirling flow, thereby smoothly returning the oil carried out by the tubing 5 back into the wellhead 10 without the need for further processing of the temporarily stored oil, thus improving the convenience of operation.

[0035] If the oil carried out by the oil pipe 5 is viscous, or if there is still residual oil after the return flow is completed, water can be injected to flush it out. This allows the axial spiral guide vanes 14 and / or the radial spiral guide vanes 13 to form a swirling flow that drives the oil back. Alternatively, the inner cylinder 11 can be rotated. Specifically, the axial spiral guide vanes 14 are mounted on the inner cylinder 11, and the radial spiral guide vanes 13 are mounted on the inner cylinder 11 via the base plate 12. As long as a drive structure is provided to rotate the inner cylinder 11, the axial spiral guide vanes 14 and the radial spiral guide vanes 13 can be rotated, thereby actively driving the oil flow to assist the oil backflow.

[0036] like Figure 1 and Figure 2 As shown, a collection groove 3 is provided on the top of the first outer cylinder 2. The diameter of the collection groove 3 is larger than the diameter of the first outer cylinder 2. The collection groove 3 forms an flared structure of the first outer cylinder 2, which can conveniently collect the splashed oil and increase the internal capacity of the first outer cylinder 2, thereby increasing the temporary storage capacity of the oil.

[0037] Overflow pipe 8 is connected between collection tank 3 and second outer cylinder 1, wherein, as Figure 1 As shown, the inlet of the overflow pipe 8 is installed tangentially on the collecting tank 3. The swirling flow formed in the second return chamber faces the inlet of the overflow pipe 8. The presence of swirling flow in the second return chamber facilitates the entry of oil into the overflow pipe 8. Figure 4 As shown, the outlet of the overflow pipe 8 is installed tangentially to the second outer cylinder 1, and the outlet of the overflow pipe 8 faces the direction of the swirling flow formed in the third return liquid chamber. This allows the oil flowing out of the overflow pipe 8 to better achieve the swirling flow formation within the third return liquid chamber. Therefore, when the oil and water in the collection tank 3 overflow, they can more effectively enter the overflow pipe 8 with the help of the swirling flow formed in the second return liquid chamber. Simultaneously, the liquid flow entering the third return liquid chamber follows the swirling flow formed in the third return liquid chamber, further improving the swirling effect, increasing the fluidity of the oil, and facilitating oil return.

[0038] like Figure 1 and Figure 2 As shown, a telescopic bellows 4 is installed on the top of the collection tank 3. The diameter of the telescopic bellows 4 is the same as the large opening diameter of the collection tank 3. Since oil may splash when the oil pipe 5 is pulled out, the height of the collection tank 3 can be increased by stretching the bellows 4 to shield the splashed oil, thereby avoiding environmental pollution and waste caused by oil splashing. When the oil stops splashing, the height of the bellows 4 is compressed to facilitate operation inside the collection tank 3.

[0039] like Figure 1 and Figure 2 As shown, the height of the first outer cylinder 2 is greater than the height of the second outer cylinder 1. The first outer cylinder 2 is mainly used to form axial swirling flow, while the second outer cylinder 1 can be used to form radial swirling flow (the bottom plate 12 can be set in a form that is lower in the middle and higher around the edges, which makes it easier for the oil to flow towards the center). The diameter of the second outer cylinder 1 is greater than the diameter of the collecting tank 3. A perforated plate 9 is installed on the top of the third return fluid chamber. When some oil overflows or splashes out from the collecting tank 3, it can fall onto the perforated plate 9 and then enter the third return fluid chamber through the perforated plate 9, and then flow back to the wellhead 10. Therefore, the third return fluid chamber can not only receive the oil overflowing from the collecting tank 3 through the overflow pipe 8, but also receive the oil splashed / overflowing from the collecting tank 3 or the corrugated pipe 4 under special circumstances, thereby further improving the oil collection and return effect.

[0040] like Figure 1 , Figure 2 and Figure 6 As shown, an oil scraper ring 6 is installed on the top of the inner cylinder 11. The oil scraper ring 6 is made of flexible material and can be set in a whole circle or in segments. It is set in a whole ring around the outer diameter side of the oil pipe 5 and fixed by a clamp 20. The clamp 20 can be fixed on the oil baffle 7. The inner diameter of the oil scraper ring 6 in its undeformed state is less than or equal to the outer diameter of the oil pipe 5, so that it can better fit the outer diameter of the oil pipe 5 and remove the oil adhering to the outer wall of the oil pipe 5. The segmented oil scraper ring 6 can achieve a better deformation effect.

[0041] like Figure 1 , Figure 2 , Figure 3 and Figure 5 As shown, an oil baffle 7 is installed on the top of the inner cylinder 11. The outer diameter of the oil baffle 7 is between the diameter of the inner cylinder 11 and the diameter of the first outer cylinder 2. The oil baffle 7 is installed on the top of the inner cylinder 11 via a support column 19. A through hole for the oil pipe 5 is provided in the middle of the oil baffle 7. The oil scraper ring 6 is concentric with the through hole and is installed on the oil baffle 7. The oil baffle 7 forms a support for the oil scraper ring 6, thereby scraping off the oil from the outer wall of the oil pipe 5. Since the oil baffle 7 is installed on the top of the inner cylinder 11 via the support column 19, it can not only block the oil from spraying from the wellhead 10 to a certain extent, but also guide part of the blocked oil through the gap between the oil baffle 7 and the inner cylinder 11 to the second return fluid chamber, and guide the sprayed oil through the upper surface of the oil baffle 7 to the second return fluid chamber, which facilitates the distribution and flow of the oil.

[0042] like Figure 4 As shown, the bottom of the first outer cylinder 2 is provided with a first return port 17 connecting the second and third return ports. An inwardly opening baffle 16 is provided on the inner side of the first return port 17. Under the action of the internal oil, the inwardly opening baffle 16 can adhere to the inner wall of the first outer cylinder 2, thereby preventing oil from flowing from the second return port into the third return port and backflowing upwards from the perforated plate 9. Simultaneously, the inwardly opening baffle 16 can be smoothly opened under the action of the oil in the third return port, allowing the oil to smoothly enter the second return port from the third return port. Furthermore, a tangential guide plate 15 is provided on the outer side of the first return port 17, which can guide the oil and better direct the oil flow through the first return port 17.

[0043] like Figure 4 and Figure 5 As shown, the bottom of the inner cylinder 11 is provided with a second return port 18 that connects the first return fluid chamber and the second return fluid chamber. The second return port 18 is evenly distributed along the circumference. The oil in the second return fluid chamber can smoothly pass through the second return port 18 and flow back into the first return fluid chamber and then back into the wellhead 10.

[0044] The working principle of this invention is as follows:

[0045] The corrugated pipe 4 is extended upwards to raise the height of the collection tank 3. The tubing 5 is pulled out from the wellhead 10, and the oil in the wellhead 10 sprays upwards, with the corrugated pipe 4 preventing oil splashing. Under the oil pressure at the wellhead 10, the oil gradually fills the first and second return chambers. Because the upward oil pressure at the wellhead 10 is relatively high at this time, the oil does not flow back temporarily. When there is a large amount of oil, the oil enters the third return chamber through the overflow pipe 8. After the pressure at the wellhead 10 gradually decreases, the oil in the first, second, and third return chambers begins to flow back. Among them, the oil in the second return chamber forms an axial downward swirling flow under the action of the axial spiral guide vane 14, and the oil in the third return chamber forms a radial inward swirling flow under the action of the radial spiral guide vane 13. The two sets of swirling flows intersect and merge, forming a better flowing oil and promoting the return of the oil. Finally, the oil flows back into the wellhead 10 through the first return chamber.

[0046] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An oil return device characterized by comprising: The system includes a base plate and an inner cylinder, a first outer cylinder, and a second outer cylinder, which are sequentially nested from the inside out on the base plate. The base plate is fixedly connected to the wellhead. A first return fluid chamber is formed inside the inner cylinder and communicates with the wellhead. A second return fluid chamber is formed between the inner cylinder and the first outer cylinder and communicates with the first return fluid chamber. A third return fluid chamber is formed between the first outer cylinder and the second outer cylinder and communicates with the second return fluid chamber. Oil carried out by the tubing through the wellhead enters the first return fluid chamber and the second return fluid chamber, and then enters the third return fluid chamber through the overflow pipe. The second return fluid chamber is equipped with axial spiral guide vanes, and the third return fluid chamber is equipped with radial spiral guide vanes. When the oil flows back, the swirling direction formed in the second return fluid chamber is the same as the swirling direction formed in the third return fluid chamber. The oil forming the swirling flow flows back into the wellhead from the first return fluid chamber. A collection groove is provided at the top of the first outer cylinder, and the diameter of the collection groove is larger than the diameter of the first outer cylinder; Axial spiral guide vanes are installed on the inner cylinder, and radial spiral guide vanes are installed on the inner cylinder through the base plate. A drive structure is set to drive the inner cylinder to rotate. The rotation of the axial spiral guide vanes and radial spiral guide vanes actively drives the oil flow to assist the oil backflow.

2. The oil return device according to claim 1, characterized by: The inlet of the overflow pipe is installed tangentially on the collection tank, and the swirling flow formed in the second return chamber is directed toward the inlet of the overflow pipe.

3. The oil return device according to claim 2, characterized by: The outlet of the overflow pipe is installed tangentially on the second outer cylinder, and the outlet of the overflow pipe faces the swirling direction formed in the third return liquid chamber.

4. The oil reflux device according to claim 1, characterized in that: A telescopic corrugated pipe is installed on the top of the collection tank, and the diameter of the telescopic corrugated pipe is the same as the large opening diameter of the collection tank.

5. The oil reflux device according to claim 1, characterized in that: The height of the first outer cylinder is greater than the height of the second outer cylinder, the diameter of the second outer cylinder is greater than the diameter of the collection tank, and a perforated plate is installed on the top of the third return chamber.

6. The oil reflux device according to claim 1, characterized in that: An oil scraper ring is installed at the top of the inner cylinder. The oil scraper ring is made of flexible material, and its inner diameter in its undeformed state is less than or equal to the outer diameter of the oil pipe.

7. The oil reflux device according to claim 6, characterized in that: An oil baffle is installed on the top of the inner cylinder. The outer diameter of the oil baffle is between the diameter of the inner cylinder and the diameter of the first outer cylinder. The oil baffle is installed on the top of the inner cylinder by a support column. A through hole is provided in the middle of the oil baffle to penetrate the oil pipe. The oil scraper ring is concentric with the through hole and is installed on the oil baffle.

8. The oil reflux device according to claim 1, characterized in that: The bottom of the first outer cylinder is provided with a first return port that connects the second return chamber and the third return chamber. An inwardly opening baffle is provided on the inner side of the first return port, and a tangential guide plate is provided on the outer side of the first return port.

9. The oil reflux device according to claim 1, characterized in that: The bottom of the inner cylinder is provided with a second return port that connects the first return liquid chamber and the second return liquid chamber, and the second return liquid port is evenly distributed along the circumference.

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