CN113464092A

CN113464092A - Wax control device and oil recovery wax control tubular column

Info

Publication number: CN113464092A
Application number: CN202010240379.9A
Authority: CN
Inventors: 匡韶华; 王宝权; 张建军; 吕民; 张洪宝; 佟姗姗; 严蕾; 刘天琦; 岳志强; 田富
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2021-10-01

Abstract

The invention relates to a wax-proof device and an oil extraction wax-proof tubular column, wherein the wax-proof device comprises a heat transfer pipe and a circulating pump, the heat transfer pipe comprises a spiral pipe and a heat insulation sleeve wrapped on the outer wall of the middle part of the spiral pipe, the spiral pipe is formed by folding and spirally winding a heat conduction pipe, the two parts of the heat conduction pipe formed after folding are respectively used as a liquid inlet pipe and a liquid outlet pipe, and the inner cavity of the spiral pipe is filled with heat conduction liquid. The open end of the liquid inlet pipe is connected with the liquid outlet end of the circulating pump, and the open end of the liquid outlet pipe is connected with the liquid inlet end of the circulating pump. The invention can utilize terrestrial heat to improve the temperature of the shaft, fundamentally prevent the wax precipitation of the shaft, has low cost, does not pollute an oil layer, can realize continuous wax prevention, does not need to shut down the well and remove the wax regularly, and ensures the normal production of an oil well.

Description

Wax control device and oil recovery wax control tubular column

Technical Field

The invention relates to the technical field of oil extraction, in particular to a wax-proof device and an oil extraction wax-proof tubular column.

Background

The gas lift oil extraction technology is widely applied to various oil fields at home and abroad, and is an oil extraction mode which continuously injects natural gas into an oil pipe through a gas lift valve arranged on the oil pipe, mixes the natural gas with liquid in the oil pipe and reduces the density of a liquid column so as to lift a shaft liquid column to the ground. However, in the case of oil wells with high wax content in crude oil, wax precipitation phenomenon is commonly caused in gas lift wells because injected gas aggravates the reduction of the temperature of a well bore. And the wax precipitation of the oil pipe can cause the yield to drop, the gas lift efficiency is reduced, and the wax blocks the oil pipe in serious conditions, so that the production cannot be carried out.

At present, aiming at the wax deposition phenomenon, the commonly used gas lift well wax removal process mainly comprises mechanical wax scraping, thermal cleaning wax removal, chemical wax removal and electric heating wax removal. However, these wax removal and prevention processes have problems in practical application processes, wherein mechanical wax removal cycle is short and wax removal cost is high; the hot washing, paraffin removal and well washing time is long, and the well washing liquid solution pollutes oil layers; mechanical paraffin removal and thermal wax cleaning require periodic shut-in operations, which affects production; the chemical paraffin removal cost is high, and the chemical paraffin removal has a corrosive effect on a gas lift valve; the electric heating paraffin removal risk is large and the cost is high.

Therefore, the inventor provides a wax-proof device and a gas-lift oil production string by virtue of experience and practice of related industries for many years so as to overcome the defects in the prior art.

Disclosure of Invention

The invention aims to provide a paraffin control device and an oil extraction paraffin control tubular column, which can improve the temperature of a shaft by utilizing terrestrial heat, fundamentally prevent the shaft from generating paraffin precipitation, have low cost, do not pollute an oil layer, can realize continuous paraffin control, do not need to shut down a well regularly to remove paraffin, and ensure the normal production of an oil well.

The purpose of the invention can be realized by adopting the following technical scheme:

the invention provides a wax-proofing device, which comprises a heat transfer pipe and a circulating pump; the heat transfer pipe comprises a spiral pipe and a heat insulation sleeve wrapped on the outer wall of the middle part of the spiral pipe, the spiral pipe is formed by folding and spirally winding a heat conduction pipe, the two parts of the heat conduction pipe formed after folding are respectively used as a liquid inlet pipe and a liquid outlet pipe, and heat conduction liquid is filled in the inner cavity of the spiral pipe; the open end of the liquid inlet pipe is connected with the liquid outlet end of the circulating pump, and the open end of the liquid outlet pipe is connected with the liquid inlet end of the circulating pump.

In a preferred embodiment of the present invention, the heat conducting pipe is a seamless steel pipe, the heat conducting liquid is heat conducting oil, and the heat insulating sleeve is made of phenolic foam composite heat insulating material.

In a preferred embodiment of the present invention, the heat transfer tube further includes a protective jacket covering the outside of the spiral tube, and the heat insulating jacket is sandwiched between the spiral tube and the protective jacket.

In a preferred embodiment of the invention, the protective sleeve is formed by winding a flat aluminum strip around the outside of the spiral tube.

In a preferred embodiment of the invention, the device further comprises a hanger which is vertically arranged; the upper end of the hanger is fixed with a mounting plate, two through holes are arranged on the mounting plate, the upper end of the heat transfer pipe is arranged in the inner cavity of the hanger in a penetrating mode, and the open ends of the liquid inlet pipe and the liquid outlet pipe are connected with the circulating pump after penetrating out of the corresponding through holes in the mounting plate respectively.

The invention also provides an oil extraction paraffin prevention pipe column, which comprises: the oil pipe column is vertically arranged; and the heat transfer pipe is inserted in the oil pipe column, and the lower end of the heat transfer pipe penetrates through the oil pipe column and extends downwards.

In a preferred embodiment of the present invention, the tubing string comprises at least one set of gas lift tubing, each set of gas lift tubing comprising an insulated tubing and a gas lift valve arranged one above the other.

In a preferred embodiment of the present invention, the thermal insulation pipe is a vacuum thermal insulation pipe.

In a preferred embodiment of the invention, the tubing string further comprises a packer at the bottom end.

In a preferred embodiment of the invention, a backwash valve is also provided between the gas lift tubing and the packer.

In a preferred embodiment of the invention, a plurality of groups of gas lift oil pipes are arranged, and the opening pressure of each gas lift valve and the opening pressure of each backwashing valve are increased from top to bottom in sequence.

In a preferred embodiment of the invention, the tubing string further comprises a flare disposed at a lower end of the packer.

According to the invention, the heat absorption section of the spiral pipe is arranged corresponding to the position of the production layer when the oil well production layer heat insulation device is used through the matching of the circulating pump and the spiral pipe, so that the heat conduction liquid of the heat absorption section of the spiral pipe can continuously absorb the heat of the production layer, the heat loss of the heat insulation section of the spiral pipe can be prevented by utilizing the heat insulation sleeve, meanwhile, the heat conduction liquid is driven to circularly flow in the spiral pipe through the circulating pump, and further, the heat of the oil well production layer can be continuously transmitted to the upper part of the shaft, so that the temperature of the shaft on the upper part is improved, and the wax precipitation of the shaft is fundamentally prevented.

Compared with the existing wax removal and prevention process, the invention has the advantages of simpler structure, simple and convenient operation, low energy consumption and capability of realizing low-cost wax removal and prevention by utilizing terrestrial heat to improve the temperature of a shaft; and continuous wax control can be realized, the well does not need to be closed regularly to remove wax, the oil layer is not polluted, and the normal production of the oil well is not influenced. In addition, the spiral pipe is processed by adopting a mode of spirally winding a single heat conduction pipe, so that the heat absorption and heat dissipation areas of the heat conduction pipe are increased, the heat conduction effect is improved, and the heat conduction pipe is convenient to pull up and down.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention.

Wherein:

FIG. 1: the invention provides a schematic structural diagram of the oil extraction paraffin prevention pipe column.

FIG. 2: is a structural schematic diagram of the heat transfer pipe provided by the invention.

FIG. 3: the invention provides a structural schematic diagram of a Christmas tree and a hanger.

Wherein the arrows in fig. 1 and 3 represent the flow direction of the heat transfer liquid.

The reference numbers illustrate:

1. a heat transfer tube; 11. a spiral tube; 111. a liquid inlet pipe; 112. a liquid outlet pipe; 12. a heat insulating sleeve; 13. a protective sleeve; 14. a heat absorption section; 15. a heat insulation section; 16. a heat dissipation section;

2. a circulation pump;

3. a hanger; 31. mounting a plate;

4. a Christmas tree;

5. an oil pipe string; 51. a heat insulation oil pipe; 52. a gas lift valve; 53. a backwash valve; 54. a packer; 55. a bell mouth.

6. Producing a sleeve; 7. and (4) producing a stratum.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings.

As shown in fig. 1 and 2, the present embodiment provides a wax-proofing device including a heat transfer pipe 1 and a circulation pump 2. The heat transfer tube 1 comprises a spiral tube 11 and a heat insulation sleeve 12 wrapped on the outer wall of the middle part of the spiral tube 11, the spiral tube 11 is formed by folding and spirally winding a heat conduction tube, two parts of the heat conduction tube formed after folding are respectively used as a liquid inlet tube 111 and a liquid outlet tube 112, and heat conduction liquid is filled in the inner cavity of the spiral tube 11. The open end of the liquid inlet pipe 111 is connected with the liquid outlet end of the circulating pump 2, and the open end of the liquid outlet pipe 112 is connected with the liquid inlet end of the circulating pump 2.

Wherein, the liquid inlet pipe 111 and the liquid outlet pipe 112 are communicated at the bottom and spirally wound on the upper surface, the upper opening end of the liquid inlet pipe 111 is used as a liquid inlet of the spiral pipe 11, and the upper opening end of the liquid outlet pipe 112 is used as a liquid outlet of the spiral pipe 11. The spiral tube 11 in this embodiment is formed by folding and spirally winding a heat pipe, and is more convenient to process. When the heat transfer pipe is used, the connecting ends of the liquid inlet pipe 111 and the liquid outlet pipe 112 are placed downwards, the whole heat transfer pipe 1 is inserted into the oil pipe string 5 and extends out of the oil pipe string 5, and the circulating pump 2 is placed on the ground. The heat insulation sleeve 12 divides the part of the spiral pipe 11 in the shaft into a heat absorption section 14, a heat insulation section 15 and a heat dissipation section 16 from bottom to top, the length of each section is generally designed according to the temperature gradient of the shaft and the wax deposition position, the length of the heat absorption section 14 is generally equal to the depth from the bottom of the artificial well to the upper boundary of the production layer 7, the depth of the heat insulation section 15 is generally equal to the depth from the upper boundary of the production layer 7 to the wax deposition position, the length of the heat dissipation section 16 is generally equal to the depth from the wax deposition position to the well head, and the length of the heat transfer pipe 1 extending out of the bottom end of the oil pipe column 5 is generally equal to the length of the heat absorption section 14. Taking a certain gas lift well depth of 3500m, a production zone 7 thickness of 500m, a production casing 6 inner diameter of 177.8mm, and a wax deposition depth of 1500m as an example, the length of the heat absorption section 14 is about 500m, the length of the heat insulation section 15 is about 1500m, and the length of the heat dissipation section 16 is about 1500 m.

Because the zone 7 itself has a higher temperature for most wells, there is generally no wax deposition in the lower portion of the wellbore. When the gas lift oil extraction is adopted, the temperature of the upper part of the shaft is reduced due to the temperature reduction of injected gas and the heat dissipation of liquid, so that wax precipitation often occurs on the upper part of the shaft. When the wax-proofing device in the embodiment works, the heat-conducting liquid in the heat absorption section 14 is heated due to the high temperature of the production layer 7, and the heat loss of the heat-transfer pipe 1 in the middle well section can be prevented due to the action of the heat-insulating sleeve 12 in the heat-insulating section 15, so that the heating effect on the upper shaft is improved; when the heat dissipation section 16 is used, the heat of the heat conducting liquid can be released, so that the temperature of the upper shaft is increased, the temperature of the upper shaft is higher than a wax precipitation point, and the wax precipitation phenomenon of the upper shaft is prevented. Meanwhile, the heat-conducting liquid is enabled to flow in a circulating manner in the spiral pipe 11 all the time under the action of the circulating pump 2, and the heat of the stratum is effectively and continuously transferred. Because the temperature of the shaft is reduced as an important reason for wax deposition in the shaft of the gas lift well, the wax deposition in the shaft can be effectively prevented by increasing the temperature of the shaft.

From this, wax control device in this embodiment passes through circulating pump 2 and spiral pipe 11's cooperation, place the position that corresponds stratum basale 7 with spiral pipe 11's heat absorption section 14 when using, make spiral pipe 11 heat absorption section 14's heat-conducting fluid constantly absorb stratum basale 7 self heat, utilize heat-insulating sleeve 12 can prevent the calorific loss of spiral pipe 11 heat-insulating section 15, drive about heat-conducting fluid through circulating pump 2 simultaneously and circulate in spiral pipe 11, and then can constantly transmit pit shaft upper portion with oil well stratum basale 7 self heat, with the temperature that improves upper portion pit shaft, fundamentally prevents the emergence of pit shaft wax deposition.

Compared with the existing wax removal and prevention process, the structure of the embodiment is simpler, the operation is simple and convenient, the temperature of the shaft can be increased by utilizing terrestrial heat, the energy consumption is low, and the wax removal and prevention with low cost can be realized; and continuous wax control can be realized, the well does not need to be closed regularly to remove wax, the oil layer is not polluted, and the normal production of the oil well is not influenced. In addition, adopt single heat pipe spiral winding's mode processing spiral pipe 11 in this embodiment, not only increased the heat absorption and the heat radiating area of heat-transfer pipe 1, improved the heat conduction effect, be convenient for the operation of getting off of heat-transfer pipe 1 moreover.

It should be noted that the paraffin control device in this embodiment can be applied to not only paraffin control for gas lift wells, but also paraffin control for any flowing well, and can perform a better paraffin control function.

In a specific embodiment, the heat transfer pipe is preferably a seamless steel pipe for ease of processing and heat transfer effect. In order to ensure the heat conduction effect, the heat conduction liquid is preferably heat conduction oil. In order to ensure the heat insulation effect, the heat insulation sleeve 12 is preferably made of phenolic foam composite heat insulation material. Of course, according to actual needs, the heat conduction pipe can also be made of other materials which have good heat conduction effects and meet the technological properties of high temperature resistance, corrosion resistance and the like; the heat-conducting liquid can also adopt other liquids with better heat conductivity coefficient and capable of rapidly heating; the heat insulation sleeve 12 may be made of other heat insulation materials as long as it can perform a better heat insulation function, and this embodiment is only an example.

In order to protect the spiral tube 11, as shown in fig. 2, the heat transfer tube 1 further includes a protective jacket 13 wrapped around the spiral tube 11, and the heat insulating jacket 12 is sandwiched between the spiral tube 11 and the protective jacket 13.

In practical applications, since the heat transfer tube 1 has a long length, the protective sleeve 13 is formed by winding a flat aluminum strip around the outside of the spiral tube 11 in order to facilitate storage of the heat transfer tube 1 when the heat transfer tube 1 is not in use.

The dimensions of the flat aluminum strip are selected as required, and for example, the thickness of the flat aluminum sheet in this embodiment is 1.5mm, and the width is 3 mm. Like this, convolute winding on spiral pipe 11 with flat aluminum sheet round of round for whole protective sheath 13 has certain pliability, and seamless steel pipe also has certain pliability, consequently, whole heat-transfer pipe 1 alright roll up when not using, both saved space and conveniently deposited. Of course, the protective sheath 13 may also be made of other metal materials having flexibility and satisfying the processing performances such as high temperature resistance and corrosion resistance, and the embodiment is only an example.

In order to facilitate the process of putting the oil pipe column 5 into the heat transfer pipe 1, the upper part of the heat transfer pipe 1 is hung at a wellhead, as shown in fig. 1 and 3, the whole paraffin control device further comprises a hanger 3 which is vertically arranged, a mounting plate 31 is fixed at the upper end of the hanger 3, two through holes are formed in the mounting plate 31, the upper end of the heat transfer pipe 1 is arranged in an inner cavity of the hanger 3 in a penetrating manner, and the open ends of a liquid inlet pipe 111 and a liquid outlet pipe 112 are respectively connected with a circulating pump 2 after penetrating out through corresponding through holes in the mounting plate 31.

Specifically, hanger 3 adopts slips to hang, packing element is sealed, mainly is used for hanging spiral pipe 11, and its slips hangs on the protective sheath 13 outer wall of heat-transfer pipe 1 when using, and the packing element is sat and is sealed on protective sheath 13 outer wall, and the sealing action of packing element can prevent that oil gas from spilling over. The specific structure of the hanger 3 is the prior art and will not be described in detail herein. Because the Christmas tree 4 at the wellhead is internally provided with the paraffin removal valve, the upper end of the paraffin removal valve is provided with the flange, and when the paraffin removal valve is installed, the lower end of the hanger 3 is fixedly connected with the flange at the upper end of the paraffin removal valve.

Further, as shown in fig. 1, the present embodiment also provides a production wax-prevention pipe string, which includes a vertically arranged oil pipe string 5 and the wax-prevention device, the heat transfer pipe 1 is inserted in the oil pipe string 5, and the lower end of the heat transfer pipe 1 penetrates through the oil pipe string 5 and extends downward.

Wherein, the two ends of the oil pipe column 5 are opened, and the oil well is a self-blowing well. When the oil pipe string is used, the oil pipe string 5 is firstly put into the production casing 6, so that the bottom end of the oil pipe string 5 is positioned at the upper boundary position of the production layer 7, and then the upper end of the oil pipe string 5 is connected with the Christmas tree 4 at the wellhead. After the tubing string 5 is completely put in, the heat transfer pipe 1 is inserted into the tubing string 5 from the upper end of the paraffin removal valve of the Christmas tree 4 and extends out of the bottom end of the tubing string 5 to enter a production zone 7 and approach the position of an artificial well bottom. And then fixing the lower end of the hanger 3 at the upper end of the paraffin removal valve, enabling the liquid inlet pipe 111 and the liquid outlet pipe 112 to penetrate out of the hanger 3, and then hanging the slips of the hanger 3 and setting the rubber cylinder to realize the hanging of the heat transfer pipe 1. Then, the wax control operation of the wax control device and the oil extraction operation of the oil pipe column 5 can be simultaneously carried out, so that the normal oil extraction is ensured, and the wax control effect can be effectively realized. When well repair is needed, the heat transfer pipe 1 can be directly taken out, the construction operation is simple, and the risk is low.

In the specific implementation process, when the pipe string 5 is applied to a gas lift well, the pipe string comprises at least one group of gas lift oil pipes, and each group of gas lift oil pipes comprises an up-and-down thermal insulation oil pipe 51 and a gas lift valve 52.

The number of the groups of the gas lift oil pipes is determined according to the actual well depth, 4-6 groups are generally arranged, and when a plurality of groups of gas lift oil pipes are arranged, the gas lift oil pipes are sequentially connected in series from top to bottom. The gas lift valve 52 is essentially a one-way valve, and the specific structure is prior art, and the invention is not limited thereto. Thus, in operation, natural gas is injected into the oil jacket annulus, and the natural gas enters the tubing string 5 mainly through the gas lift valves 52, thereby lifting the wellbore fluid column to the surface. And the wax deposition on the upper part of the shaft can be prevented when the wax control device is arranged for gas lift oil extraction, and the heat insulation oil pipe 51 and the heat transfer pipe 1 are matched for use, so that the formation heat can be utilized to the maximum extent from the aspects of heat preservation and heating, the heat loss can be reduced, the temperature of the shaft can be further improved, and the wax deposition on the shaft can be effectively prevented.

In practical applications, the thermal insulation oil pipe 51 is a vacuum thermal insulation pipe in order to ensure the thermal insulation effect of the thermal insulation oil pipe 51. The vacuum heat insulation oil pipe 51 generally comprises double oil pipes, and the gap between the double oil pipes is vacuumized to achieve the purpose of heat insulation. The specific structure of the vacuum insulation oil pipe 51 is the prior art and will not be described in detail herein.

To avoid the risk of high pressure blow-by conditions in the oil jacket annulus during gas lift production, the tubing string 5 also includes a packer 54 at the bottom end, as shown in FIG. 1.

Like this, after going into tubing string 5, through lifting and putting down and setting packer 54, just can separate the oil jacket annular space, when avoiding appearing the steam channeling in the oil jacket annular space, cause the blowout and take place danger, also can play certain guard action to upper portion production casing 6 simultaneously, prevent that it from being corroded by gas.

The general packer 54 is set at a position 20-50 m above the production zone 7, and in order to facilitate the heat transfer pipe 1 to smoothly pass through the packer 54, the packer 54 is a large-drift-diameter packer 54, and the inner drift diameter of the packer 54 is larger than the outer diameter of the heat transfer pipe 1 by more than 6 mm.

Further, a backwash valve 53 is provided between the gas lift tubing and the packer 54 to facilitate killing or flushing operations. Wherein, the back washing valve 53 is also a one-way valve, and the specific structure is the prior art. When the well is washed circularly, liquid is pumped from the hollow part of the oil ring and is pressed on the ground, and at the moment, the liquid flows into the oil pipe column 5 from each gas lift valve 52 and each backwashing valve 53, so that the effect of reverse circulation well washing is realized.

In practical application, in order to facilitate the control of oil production according to process requirements and simultaneously reduce the opening pressure of each gas lift valve 52 and the backwashing valve 53, a plurality of groups of gas lift oil pipes are arranged, and the opening pressure of each gas lift valve 52 and the backwashing valve 53 is sequentially increased from top to bottom. Thus, during normal oil production, the backwash valve 53 is closed all the time, and each gas lift valve 52 is opened partially or fully as required for production. When the well is washed in a circulating manner and is pressed, the gas lift valves 52 are sequentially opened step by step from top to bottom, and finally the backwashing valve 53 is opened to realize reverse circulation well washing.

Further, in order to facilitate the smooth running and pulling of the heat transfer tube 1, the tubing string 5 further includes a bell 55 disposed at the lower end of the packer 54, and the bell 55 is typically located at the upper boundary of the production zone 7 when the tubing string 5 is run.

In summary, the wax control device and the oil extraction wax control tubular column in the embodiment can continuously transfer the heat at the bottom of the well to the upper part of the well, reduce the heat loss through the heat preservation effect of the heat insulation oil pipe 51, and effectively prevent the wax deposition of the well.

The above are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent changes and modifications that can be made by one skilled in the art without departing from the spirit and principles of the invention should fall within the protection scope of the invention.

Claims

1. The wax control device is characterized by comprising a heat transfer pipe and a circulating pump;

the heat transfer pipe comprises a spiral pipe and a heat insulation sleeve wrapped on the outer wall of the middle part of the spiral pipe, the spiral pipe is formed by folding and spirally winding a heat conduction pipe, two parts of the heat conduction pipe formed after folding are respectively used as a liquid inlet pipe and a liquid outlet pipe, and heat conduction liquid is filled in the inner cavity of the spiral pipe;

the opening end of the liquid inlet pipe is connected with the liquid outlet end of the circulating pump, and the opening end of the liquid outlet pipe is connected with the liquid inlet end of the circulating pump.

2. The wax control device of claim 1,

the heat conduction pipe is a seamless steel pipe, the heat conduction liquid is heat conduction oil, and the heat insulation sleeve is made of phenolic foam composite heat insulation materials.

3. The wax control device of claim 1,

the heat transfer pipe also comprises a protective sleeve wrapped on the outer side of the spiral pipe, and the heat insulation sleeve is clamped between the spiral pipe and the protective sleeve.

4. The wax control device of claim 3,

the protective sleeve is formed by winding a flat aluminum strip outside the spiral tube in a spiral mode.

5. The wax control device of claim 1, further comprising a vertically disposed hanger;

the upper end of hanger is fixed with the mounting panel, two through-holes have been seted up on the mounting panel, wear to establish in the inner chamber of hanger the upper end of heat-transfer pipe, just the open end of feed liquor pipe and drain pipe respectively by the through-hole that corresponds on the mounting panel is worn out the back and is connected with the circulating pump.

6. An oil recovery paraffin control string, comprising:

the oil pipe column is vertically arranged;

and the paraffin control device according to any one of claims 1 to 5, the heat transfer pipe being inserted in the tubing string with a lower end of the heat transfer pipe penetrating the tubing string and extending downward.

7. The production wax control string of claim 6,

the oil pipe string comprises at least one group of gas lift oil pipes, and each group of gas lift oil pipes comprises a heat insulation oil pipe and a gas lift valve which are arranged from top to bottom.

8. The production wax control string of claim 7,

the heat insulation oil pipe is a vacuum heat insulation pipe.

9. The production wax control string of claim 7,

the tubing string further comprises a packer at the bottom end.

10. The production wax control string of claim 9,

and a backwashing valve is also arranged between the gas lift oil pipe and the packer.

11. The production wax control string of claim 10,

and a plurality of groups of gas lift oil pipes are arranged, and the opening pressure of each gas lift valve and the opening pressure of the backwashing valve are sequentially increased from top to bottom.

12. The production wax control string of claim 9,

the oil pipe column further comprises a bell mouth arranged at the lower end of the packer.