Sand prevention, steam injection and oil extraction integrated pipe column and using method thereof

Abstract

The invention relates to a sand prevention, steam injection and oil extraction integrated pipe column and a using method thereof. In the integrated pipe column, a heat insulation compensator outer pipe is arranged between a sand prevention screen pipe and a sand prevention and steam injection packer in the sand prevention pipe column; a pump seat of a rod type oil well pump at the lower end of the steam injection and oil extraction pipe column is sequentially connected with a steam injection and oil extraction change-over switch and a heat insulation compensator insertion pipe; a liquid flow channel is formed in the steam injection and oil extraction change-over switch, and a change-over valve ball is arranged in the liquid flow channel; the heat insulation compensator insertion pipe can penetrate through an inner channel of the sand prevention steam injection packer to be inserted into the heat insulation compensator outer pipe, and a steam injection oil extraction channel is formed by the heat insulation compensator insertion pipe and a liquid flow channel in the steam injection oil extraction change-over switch. The liquid flow channel can be communicated with the oil sleeve annulus to form a well washing circulation channel, and a change-over valve ball in the liquid flow channel can close the well washing circulation channel and open the steam injection and oil extraction channel at the same time or open the well washing circulation channel and close the steam injection and oil extraction channel at the same time. Casing damage and operation procedures can be reduced, the production cost is reduced, and the exploitation effect of a steam injection oil production well is improved.

Description

Technical Field

[0001] The invention relates to an oil well sand control steam injection oil production pipe string for oil and gas production in the petroleum industry, in particular to a sand control steam injection oil production integrated pipe string and a use method thereof. Background Art

[0002] In the development of heavy oil fields, the use of steam huff-and-puff technology is currently a common method. Steam with a certain dryness and pressure is injected into the well on the ground to achieve the purpose of heating the oil in the formation and reducing the viscosity for easy extraction. The entire process goes through three stages: steam injection, well soaking, and oil production. Before steam injection, it is necessary to replace the steam injection pipe string and wellhead, and then replace the oil production pipe string and wellhead for oil production after well soaking; until the production of the steam-injected oil production well drops to a low point, the next round of steam injection, well soaking and oil production will be carried out. With the extension of mining time and the increase in steam injection and oil production rounds, heavy oil thermal recovery wells generally have the following problems: 1. The number of casing heat damage wells increases year by year: Because the casing between the steam injection pipe string and the sand-proof fish top is in direct contact with high-temperature steam, it is damaged by thermal stress and corrosion, causing casing damage. The casing damage in the exposed well section accounts for about 65%. According to statistics, the casing damage caused by steam injection in heavy oil thermal recovery wells increases year by year, and the recoverable reserves are also affected.

[0003] 2. The use of thermal packers for sealing in steam injection oil production wells poses a hidden danger to well control: The thermal packer is an expandable packer, which expands when pressurized by heat and acts as a seal. During the shutdown and well soaking stages, the thermal packer seal fails. At this time, if the casing is damaged and leaks, it will cause a blowout accident.

[0004] 3. The heat insulation effect during the steam injection stage is not ideal, which affects the steam injection dryness: The lack of heat insulation of the tubing compensator is an important factor affecting the heat insulation effect during the steam injection stage. The test dryness of steam at the wellhead is about 80%. The test result at 1000m underground shows that the average dryness is only about 50%, and the heat insulation effect is 60%-65%, with a large heat loss. At the same time, the "hot fast effect" heats the casing, causing most of the mud circulation holes in the casing to spray mud and emit steam, resulting in a deficit in the surface casing and the cementing slurry section of the oil-casing annulus. Statistics show that most steam injection wells without cement rings in the surface casing and the oil-casing annulus have casing corrosion, which is easy to cause "perforation"; while steam injection wells with cement rings in the oil-casing annulus are conducive to avoiding casing corrosion, but are prone to "cracks" of the cement ring after heating.

[0005] 4. The cold damage of the leaking formation caused by the well washing and pressure operation affects the oil production effect: After the heavy oil thermal production well is injected with steam, it is necessary to wash the well and then pull out the steam injection string, especially when pump leakage occurs during the production process and the well needs to be washed. Due to the high pressure of the oil-thick well washing, the low temperature of the well washing fluid and the low formation pressure, the well washing fluid enters the formation, causing cold damage to the high-temperature formation after steam injection, resulting in a long drainage period of the oil well, reduced production, and even water production without oil.

[0006] 5. Conventional sand control and steam injection thermal recovery procedures are numerous, which affect the timeliness of operations: conventional heavy oil thermal recovery wells are sand controlled and pumped out. The pumping out operation needs to go through the following procedures: well scraper, sand control tool, sand control - sand control string - sand flushing string - sand flushing string - well scraper - well scraper - steam injection string for thermal packer insulation pipe - well washing - thermal packer insulation pipe for steam injection - tubing pump with tubing - sucker rod with piston, etc., more than 10 procedures, which are relatively cumbersome and not conducive to improving operation quality and efficiency.

[0007] Through patent search, the relevant patent documents detected are as follows: the integrated tubing disclosed by patent number "CN201720763178.0": the utility model provides an integrated tubing, including: an oil pipe, a first packer, a secondary plugging valve, a first screen pipe, a second packer, a second screen pipe and a pump-out plugging valve; wherein the oil pipe includes a first section and a second section connected, the first packer is arranged in the first section of the oil pipe, the secondary plugging valve, the first screen pipe, the second packer, the pump-out plugging valve and the second screen pipe are arranged in sequence in the second section of the oil pipe, and the second screen pipe is arranged at the bottom of the second section of the oil pipe; the secondary plugging valve is used to achieve two-way plugging of the parallel layer to be mined.

[0008] The above-mentioned integrated pipe string can realize the stratified production, plugging and acidizing transformation of oil and gas wells in two production layers without moving the pipe string, thus improving the efficiency of well completion. However, it cannot mix water and inject steam into the oil pipe, which belongs to the field of "stratified production, plugging and acidizing transformation of oil and gas wells in production layers".

[0009] The injection and production string disclosed by patent number "CN201720674972.8": This utility model provides an injection and production string, which includes an oil pipe, a sucker rod, a primary injection and production pump, a screen tube and a plug. The upper end of the primary injection and production pump is connected to the oil pipe, and the lower end of the primary injection and production pump is connected to the upper end of the screen tube. The lower end of the screen tube is provided with a plug for sealing. The sucker rod is inserted into the oil pipe, and the sucker rod is connected to the reducing connecting rod of the primary injection and production pump. The reducing connecting rod is driven to move by the sucker rod, and the primary injection and production pump can be adjusted to inject gas or produce oil through the oil pipe. The primary injection and production pump is used to inject gas through the oil pipe during gas injection, which can reduce the problems of casing corrosion and cracking and casing damage during gas injection and oil replacement.

[0010] The above invention is a conventional tubular pump oil production string, and the defect of the string is that the upper pump barrel will be eroded by steam during the steam injection process, causing destructive damage to the pump.

[0011] Patent No. "CN200520084353.0" discloses a hollow rod oil production multi-purpose liquid injection device: This utility model discloses a hollow rod oil production multi-purpose liquid injection device used in the petroleum industry, in which a liquid injection mechanism is installed below the upper joint, which is suitable for oil production wells produced with hollow rods.

[0012] The above utility model is only a liquid-adding device used in conjunction with a hollow rod.

[0013] Therefore, it is necessary to reduce casing damage and operating procedures, improve thermal insulation effect and steam injection dryness, and prevent well washing fluid from leaking into the formation and causing cold damage, in order to maintain the efficient development of heavy oil fields. Summary of the invention

[0014] The purpose of the present invention is to provide an integrated sand-proof steam injection oil production string and its use method, which can reduce casing damage, reduce operation procedures, improve thermal insulation effect and steam injection dryness, prevent well washing fluid from leaking into the formation and causing cold damage, reduce production costs, and improve the production effect of heavy oil steam injection oil production wells.

[0015] The technical solution of the present invention is: an integrated sand-proof steam-injection oil production string, including a sand-proof string, a steam-injection oil production string and a sucker rod string. The sand-proof string is provided with a screw plug, a sand-proof screen and a sand-proof steam-injection packer. The steam-injection oil production string is formed by connecting a heat-insulating pipe with a pump seat of a rod-type oil pump. The heat-insulating pipe can hang the steam-injection oil production string on the oil pipe hanger in the wellhead big four-way. The piston of the rod-type oil pump is connected to the lower end of the hollow rod to form a sucker rod string. The piston of the rod-type oil pump is mounted together with the pump seat of the rod-type oil pump, wherein: an outer tube of a heat-insulating compensator is installed between the sand-proof screen and the sand-proof steam-injection packer in the sand-proof string; the pump seat of the rod-type oil pump at the lower end of the steam-injection oil production string is connected in sequence. It is connected with the steam injection and oil production conversion switch and the insulation compensator insert tube, and a liquid flow channel is provided in the steam injection and oil production conversion switch and a conversion valve ball is installed in the liquid flow channel; the conversion valve ball comprises an upper valve ball, a valve ball connecting rod and a lower valve ball, and the upper valve ball and the lower valve ball are connected at both ends of the valve ball connecting rod; the insulation compensator insert tube can pass through the inner channel of the anti-sand steam injection sealer and be inserted into the outer tube of the insulation compensator and form a steam injection and oil production channel with the liquid flow channel in the steam injection and oil production conversion switch; the liquid flow channel can be connected with the oil casing annulus to form a well washing circulation channel; the conversion valve ball in the liquid flow channel can simultaneously close the well washing circulation channel and open the steam injection and oil production channel, or simultaneously open the well washing circulation channel and close the steam injection and oil production channel.

[0016] Preferably, the steam injection and oil production conversion switch is also provided with a switch body, a lower ball fitting seat, a connecting sleeve and a switch upper joint, wherein: the liquid flow channel is arranged in the switch upper joint, and the connecting sleeve is threadedly connected to the lower part of the switch upper joint; the lower ball fitting seat is located below the connecting sleeve, and the switch body is threadedly connected to the switch upper joint to fix the connecting sleeve in the switch body; the upper valve ball is installed in the liquid flow channel of the switch upper joint, and the lower valve ball is installed in the lower ball fitting seat below the connecting sleeve.

[0017] Preferably, the upper valve ball installed at the upper end of the valve ball connecting rod is a conical sphere and can cooperate with the upper ball seat in the liquid flow channel; the lower valve ball installed at the lower end of the valve ball connecting rod consists of a lower sphere and a fixing cap, and the lower sphere is inserted under the limit platform at the lower part of the valve ball connecting rod and fixed by a fixing cap threadedly connected to the valve ball connecting rod.

[0018] Preferably, the liquid flow channel and the conversion valve ball arranged in the upper joint of the switch are arranged in more than three sets; the upper end of the liquid flow channel is connected to the outer wall of the upper joint of the switch, the inner side is connected to the center hole of the upper joint of the switch, the lower end is connected to the center hole of the connecting sleeve and the liquid flow hole in the lower ball fitting seat, and is connected to the center hole of the switch body through the liquid flow hole in the lower ball fitting seat.

[0019] Preferably, the lower ball fitting seat is provided with liquid flow holes that match the number and position of the liquid flow channels and the conversion valve balls, a middle partition is provided in the inner cavity of the body of the lower ball fitting seat, and the liquid flow holes are processed on the outer periphery of the middle partition; a tapered hole with a larger upper part and a smaller lower part is processed on the upper part of the liquid flow hole as the lower ball seat, and a sealing member is provided on the outer wall of the lower ball fitting seat.

[0020] Preferably, the lower body of the lower sphere in the lower valve ball is provided with an assembly groove and a center hole and the lower outer wall is in an inverted cone shape, which can be matched with the lower ball seat in the lower ball matching seat; the outer diameter formed by the fixing cap in the lower valve ball is smaller than the inner diameter of the liquid flow hole in the lower ball matching seat that passes through the lower ball seat; the fixing cap in the lower valve ball can be installed in the assembly groove of the lower sphere.

[0021] Preferably, a straightening ring is installed at the bottom of the liquid flow channel in the upper joint of the switch, the center hole of the straightening ring is concentric and has the same diameter as the center hole of the upper joint of the switch, and the body outside the center hole of the straightening ring is provided with valve ball connecting rod passing holes which are the same in number as the conversion valve ball; the outer diameter of the straightening ring is larger than the inner diameter of the center hole of the connecting sleeve, and the inner diameter of the center hole of the connecting sleeve is smaller than the outer diameter formed by the lower sphere in the lower valve ball.

[0022] Preferably, the switch body is a non-uniform-diameter cylindrical body and the upper body cavity is provided with an internal thread that can be threadedly connected to the switch upper joint, and a sealing ring is also installed above the threaded connection section between the switch body and the switch upper joint; the lower inner cavity of the switch body is provided with a lower ball fitting seat assembly step, and the lower ball fitting seat is installed on the lower ball fitting seat assembly step; the external thread at the lower part of the switch body can be threadedly connected to the thermal insulation compensator insert pipe, and the internal thread in the upper inner cavity of the switch upper joint can be threadedly connected to the lower joint of the pump seat of the rod-type oil pump.

[0023] Preferably, the sand control steam injection packer is a 445 type packer.

[0024] A method for using a sand control steam injection oil production integrated pipe string comprises the following steps: A. lowering the sand control pipe string and dropping it into the casing; B. lowering the steam injection oil production pipe string and the sucker rod string; C. injecting steam using the steam injection oil production pipe string; D. producing oil using the steam injection oil production channel; and E. washing the well using the well washing circulation channel.

[0025] Compared with the prior art, the remarkable use effect of the present invention lies in: inserting a set of sand-proof steam injection and oil production integrated pipe string provided by the present invention can achieve the following functions: first, a sand-proof steam injection packer is used instead of a "thermal-sensitive packer", and the thermal insulation compensator insert pipe passes through the sand-proof steam injection packer and is connected to the thermal insulation compensator outer pipe. During the whole process of steam injection, it is sealed and insulated, which solves the casing damage caused by thermal corrosion of the "exposed" section of the casing and the casing leakage well control hidden danger when the expansion type thermal-sensitive packer fails to seal the casing annulus during shutdown and well soaking, and can block heavy oil from entering the casing annulus, causing influence on subsequent operations. Second, the connection between the thermal insulation compensator insert pipe and the thermal insulation compensator outer pipe reduces heat loss and ensures The invention has a heat insulation effect; thirdly, the integrated pipe string of the invention can realize steam injection without moving the pipe string, prevent the cold damage caused by the leakage of well washing fluid into the formation, and "prevent backflow" during oil production, which is beneficial to the production of formation fluid; fourthly, in the subsequent rounds of steam injection, the upper end of the sucker rod string in the well can be replaced with a hanging rod short section that can hang the sucker rod, and then the sucker rod string can be hung in the wellhead big four-way, so that the sucker rod string can be safely hung with a pump for steam injection without having to lift it; at the same time, since a set of pipe strings is used for steam injection and oil production, the process of repeatedly lowering and pulling out the steam injection pipe string in the conventional heavy oil thermal recovery well pumping operation is reduced, and 6-8 processes can be reduced, so as to improve quality and efficiency, reduce production costs, and improve economic benefits.

[0026] The present invention uses a steam injection and oil production conversion switch, and adopts a thermal insulation compensator insert and a thermal insulation compensator outer tube to cooperate with a sand control steam injection packer. The heat loss of steam is small, and a set of pipe strings can be used to complete the functions of sand control, steam injection, and oil production. At the same time, normal sand flushing, viscosity reduction, and well washing and other oil production processes can be carried out.

[0027] The present invention is simple to operate, reliable in operation, and has multiple operational functions, thus simplifying the pumping operation process of the steam-throwing oil well and reducing the production cost and the labor intensity of the workers. Specifically, it is shown in the following aspects: 1. It effectively reduces casing damage, uses a sand-proof steam injection packer to replace the "thermal-sensitive packer", and uses the thermal insulation compensator insert pipe in conjunction with the thermal insulation compensator outer pipe. It is sealed and insulated during the whole process of steam injection, thus avoiding the casing between the steam injection oil production pipe string and the fish top of the sand-proof pipe string directly contacting with the high-temperature steam, and the casing being damaged by thermal stress and aggravated corrosion.

[0028] 2. It eliminates the hidden dangers of well control in casing leakage wells. The sand-proof steam injection packer is used instead of the "thermal packer". The sealing tube in the sand-proof steam injection packer adopts a combination design of soft metal seal and fluororubber seal, which can improve the sealing reliability of multiple rounds of steam injection at high temperature above 300°C. It solves the problems of failure of the expandable thermal-sensitive packer when sealing the casing annulus during shutdown and well soaking, and the well control hidden dangers in casing leakage wells. It can also prevent heavy oil from entering the casing annulus and causing adverse effects on subsequent operations.

[0029] 3. Improve the insulation effect and reduce the loss of steam dryness. The use of the insulation compensator intubation and the insulation compensator outer tube in conjunction with the sand-proof steam injection packer solves the problem that the existing compensator is not insulated during steam injection, the steam dryness is about 80% when tested at the wellhead, and the average steam dryness is about 50% when tested at 1000m underground, the heat loss is large, and the insulation effect is only 60%-65%. It solves the problem of poor insulation effect throughout the steam injection process, significantly improves the insulation effect, and reduces the loss of steam dryness. After field tests, the insulation effect of the present invention reached 70%-75%, effectively improving the steam injection effect.

[0030] 4. During oil production, the casing annulus is sealed and isolated through the steam injection oil production conversion switch, which avoids oil inflow into the casing annulus and the increase in viscosity of heavy oil degassing, and does not cause the problem of increased casing gas pressure affecting the rise of dynamic liquid level, which is beneficial to the production of heavy oil.

[0031] 5. Since the pipe column of the present invention can be safely hung with a rod and pumped for steam injection, multiple operation procedures are reduced in subsequent steam injection rounds, thereby improving construction quality and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0033] Figure 2 It is a schematic diagram of the pipe column structure for sand control construction.

[0034] Figure 3 It is a schematic diagram of the structure of the sand control string dropped into the casing.

[0035] Figure 4 It is a structural diagram of the steam injection and oil production conversion switch.

[0036] Figure 5 yes Figure 4 Schematic diagram of the structure in the AA direction.

[0037] In the figure: a plug 1, a sand control screen 2, an insulating compensator outer tube 3, an anti-sand steam injection seal 4, an insulating compensator insert 5; a steam injection and oil production conversion switch 6, a switch body 60, a lower ball fitting seat 61, a seal 62, a lower valve ball 63, a connecting sleeve 64, a straightening ring 65, a valve ball connecting rod 66, a liquid flow channel 67, an upper valve ball 68, and a switch upper joint 69; a rod-type oil pump 7, a hollow rod 8, an insulating tube 9, and an oil pipe 10. DETAILED DESCRIPTION

[0038] The accompanying drawings are for reference and illustration only and are not intended to limit the scope of protection of the present invention. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0041] See also Figure 1 - Figure 5, a sand control steam injection oil production integrated pipe string, including a sand control pipe string, a steam injection oil production pipe string and a sucker rod string, the sand control pipe string is provided with a wire plug 1, a sand control screen 2 and a sand control steam injection packer 4, the steam injection oil production pipe string is composed of a heat insulation pipe 9 connected with a pump seat of a rod-type pump 7, the heat insulation pipe 9 can hang the steam injection oil production pipe string on the oil pipe hanger in the wellhead big four-way, the piston of the rod-type pump 7 is connected to the lower end of the hollow rod 8 to form a sucker rod string, and the piston of the rod-type pump 7 is installed together with the pump seat of the rod-type pump 7, wherein: an insulation compensator outer pipe 3 is installed between the sand control screen 2 and the sand control steam injection packer 4 in the sand control pipe string; the pump seat of the rod-type pump 7 at the lower end of the steam injection oil production pipe string is connected to the steam injection oil production conversion switch 6 and the insulation The compensator insert pipe 5 is connected, a liquid flow channel 67 is provided in the steam injection and oil production conversion switch 6, and a conversion valve ball is installed in the liquid flow channel 67; the conversion valve ball includes an upper valve ball 68, a valve ball connecting rod 66 and a lower valve ball 63, and the upper valve ball 68 and the lower valve ball 63 are connected at both ends of the valve ball connecting rod 66; the thermal insulation compensator insert pipe 5 can pass through the inner channel of the anti-sand steam injection seal 4 and be inserted into the thermal insulation compensator outer tube 3 and form a steam injection and oil production channel with the liquid flow channel 67 in the steam injection and oil production conversion switch 6; the liquid flow channel 67 can be connected with the oil casing annulus to form a well washing circulation channel; the conversion valve ball in the liquid flow channel 67 can simultaneously close the well washing circulation channel and open the steam injection and oil production channel, or simultaneously open the well washing circulation channel and close the steam injection and oil production channel.

[0042] The sand control pipe column in the integrated pipe column of the present invention is mainly connected with a thread plug 1, a sand control screen 2, an insulation compensator outer pipe 3 and a sand control steam injection packer 4 from bottom to top. The thread plug 1 is connected to the lower end of the sand control screen 2, the upper end of the sand control screen 2 is connected to the insulation compensator outer pipe 3, and the upper end of the insulation compensator outer pipe 3 is connected to the lower end of the sand control steam injection packer 4. The insulation compensator insert pipe 5 in the steam injection oil production pipe column passes through the inner channel of the sand control steam injection packer 4 and is inserted into the insulation compensator outer pipe 3 to a certain depth. The upper end of the insulation compensator insert pipe 5 is connected to the lower end of the steam injection oil production conversion switch 6, the upper end of the steam injection oil production conversion switch 6 is connected to the lower end of the pump seat of the rod pump 7, and the upper end of the pump seat of the rod pump 7 is connected to the insulation pipe 9. The entire steam injection oil production pipe column is suspended on the oil pipe hanger in the wellhead big four-way through the insulation pipe 9, which can realize the functions of sand control, steam injection and oil production with one set of pipe columns.

[0043] The integrated pipe column of the present invention is connected and installed with a steam injection and oil production conversion switch 6, and steam can enter the steam injection and oil production channel of the integrated pipe column of the present invention through the insulation pipe 9. Under the action of steam pressure, the conversion valve ball in the steam injection and oil production conversion switch 6 moves upward, which can close the liquid flow channel 67 between the steam injection and oil production channel and the oil casing annulus, so that the steam can only go downward and enter the oil layer from the sand control screen pipe 2, which can significantly improve the insulation effect and steam injection dryness. The sand control steam injection packer 4 is used in the present invention, which can replace the thermal sensitive packer, reduce casing damage, and improve the production effect of heavy oil steam injection wells.

[0044] When oil production is carried out, the formation liquid enters the integrated pipe string of the present invention from the sand control screen 2, and moves upward into the steam injection and oil production channel. Under the action of the well fluid pressure, the conversion valve ball in the steam injection and oil production conversion switch 6 moves upward, closing the liquid flow channel 67 between the steam injection and oil production channel and the casing annulus, so that the formation liquid can only move upward and be lifted to the ground through the rod pump 7.

[0045] When well washing is required during production, liquid is pumped into the casing annulus from the wellhead casing valve. The liquid pushes the conversion valve ball in the liquid flow channel 67 downward, so that the steam injection and oil production channel is connected with the casing annulus. At the same time, the channel below the steam injection and oil production conversion switch 6 is closed. The well washing liquid can only be returned from the steam injection and oil production channel above the steam injection and oil production conversion switch 6, realizing the function of circulating well washing and preventing the well washing liquid from damaging the oil layer. The casing damage and operation procedures are reduced, the heat insulation effect and the steam injection dryness are improved, and the well washing liquid is effectively prevented from leaking into the formation and causing cold damage.

[0046] On the basis of the above-mentioned embodiment 1, the present invention also has the following embodiments: a preferred embodiment: the steam injection and oil production conversion switch 6 is also provided with a switch body 60, a lower ball fitting seat 61, a connecting sleeve 64 and a switch upper joint 69, wherein: the liquid flow channel 67 is arranged in the switch upper joint 69, and the connecting sleeve 64 is threadedly connected to the lower part of the switch upper joint 69; the lower ball fitting seat 61 is located below the connecting sleeve 64, and the switch body 60 is threadedly connected to the switch upper joint 69 to fix the connecting sleeve 64 in the switch body 60; the upper valve ball 68 is installed in the liquid flow channel 67 of the switch upper joint 69, and the lower valve ball 63 is installed in the lower ball fitting seat 61 below the connecting sleeve 64.

[0047] A preferred embodiment: the upper valve ball 68 installed at the upper end of the valve ball connecting rod 66 is a conical sphere and can cooperate with the upper ball seat in the liquid flow channel 67; the lower valve ball 63 installed at the lower end of the valve ball connecting rod 66 is composed of a lower sphere and a fixing cap, and the lower sphere is inserted under the limit platform at the lower part of the valve ball connecting rod 66 and fixed by a fixing cap threadedly connected to the valve ball connecting rod 66.

[0048] A preferred embodiment: the liquid flow channel 67 and the conversion valve ball arranged in the switch upper joint 69 are arranged in more than three sets; the upper end of the liquid flow channel 67 is connected to the outer wall of the switch upper joint 69, the inner side is connected to the center hole of the switch upper joint 69, the lower end is connected to the center hole of the connecting sleeve 64 and the liquid flow hole in the lower ball fitting seat 61, and is connected to the center hole of the switch body 60 through the liquid flow hole in the lower ball fitting seat 61.

[0049] A preferred embodiment: the lower ball fitting seat 61 is provided with liquid flow holes that match the number and position of the liquid flow channel 67 and the conversion valve ball, and the inner cavity of the main body of the lower ball fitting seat 61 is provided with a middle partition, and the liquid flow holes are processed on the outer periphery of the middle partition; a tapered hole with a larger upper part and a smaller lower part is processed on the upper part of the liquid flow hole as the lower ball seat, and a sealing member 62 is provided on the outer wall of the lower ball fitting seat 61 to ensure the sealing performance between the switch body 60.

[0050] A preferred embodiment: the lower body of the lower sphere in the lower valve ball 63 is provided with an assembly groove and a center hole, and the lower outer wall is in an inverted cone shape, which can be matched with the lower ball seat in the lower ball matching seat 61; the outer diameter formed by the fixing cap in the lower valve ball 63 is smaller than the inner diameter of the liquid flow hole in the lower ball matching seat 61 that passes through the lower ball seat; the fixing cap in the lower valve ball 63 can be installed in the assembly groove of the lower sphere.

[0051] A preferred embodiment: A straightening ring 65 is installed at the bottom of the liquid flow channel 67 in the switch upper joint 69. The center hole of the straightening ring 65 is concentric and has the same diameter as the center hole of the switch upper joint 69, and the body outside the center hole of the straightening ring 65 is provided with the same number of valve ball connecting rod through holes as the conversion valve ball; it can play a straightening role on the valve ball connecting rod 66 in the conversion valve ball 。 The outer diameter of the straightening ring 65 is larger than the inner diameter of the center hole of the connecting sleeve 64 , and the inner diameter of the center hole of the connecting sleeve 64 is smaller than the outer diameter formed by the lower sphere in the lower valve ball 63 , which can limit the upward movement of the lower valve ball 63 .

[0052] A preferred embodiment: the switch body 60 is a non-uniform-diameter cylindrical body and the upper body cavity is provided with an internal thread that can be threadedly connected to the switch upper joint 69, and a sealing ring is also installed above the threaded connection section between the switch body 60 and the switch upper joint 69; the lower inner cavity of the switch body 60 is provided with a lower ball fitting seat assembly step, and the lower ball fitting seat 61 is installed on the lower ball fitting seat assembly step; the external thread at the lower part of the switch body 60 can be threadedly connected to the thermal insulation compensator insert 5, and the internal thread in the upper inner cavity of the switch upper joint 69 can be threadedly connected to the lower joint of the pump seat of the rod-type oil pump 7.

[0053] A preferred embodiment: the sand-proof steam injection packer 4 is a 445-type packer. It can replace the "thermal packer". Its sealing tube adopts a combination design of soft metal seal and fluororubber seal, which can improve the sealing reliability of multiple rounds of steam injection at high temperature above 300°C, solve the well control risks of casing leakage wells during shutdown, well soaking and casing annulus sealing failure of the expandable thermal packer, and can prevent the adverse effects on subsequent operations caused by heavy oil entering the casing annulus.

[0054] A method for using a sand control and steam injection integrated oil production string includes the following steps: A. Lowering the sand control string and dropping it in the casing: First, carry out sand control construction in the oil well. In this step, the sand control string, which is connected by a threaded plug 1, a sand control screen 2, an insulation compensator outer tube 3 and a sand control steam injection packer 4 in sequence, is carried by the oil pipe 10 and lowered into the casing. Pressurization is applied from the oil pipe 10 to seal the sand control steam injection packer 4 and perform the filling and sand control process. After the sand control construction is completed, the upper oil pipe 10 is lifted out by inverting, and the sand control string is placed in the casing in the well as a drop string. Figure 3 .

[0055] B. Lowering the steam injection and oil production pipe string and the sucker rod string: After the sand control construction is completed, the steam injection and oil production pipe string consisting of the insulation pipe 9, the pump seat of the rod-type oil pump 7, the steam injection and oil production conversion switch 6 and the insulation compensator insert 5 is carried by the insulation pipe 9 and lowered into the casing, so that the insulation compensator insert 5 passes through the inner channel of the sand control steam injection packer 4 and is inserted into the insulation compensator outer pipe 3. The sucker rod string consisting of the hollow rod 8 and the rod-type oil pump 7 is lowered into the pump seat of the rod-type oil pump 7 by carrying the piston of the rod-type oil pump 7 through the hollow rod 8, realizing the composition of the integrated pipe string for sand control, steam injection and oil production.

[0056] C. Steam injection using the steam injection production pipe string: When injecting steam directly through the steam injection production channel in the steam injection production pipe string, it is necessary to lift the entire sucker rod string so that the piston of the rod-type oil pump 7 is lifted out of the pump seat of the rod-type oil pump 7, and after replacing the hollow sucker rod 8 on the upper part of the rod-type oil pump 7 with a hanging rod short joint that can hang the sucker rod, the entire sucker rod string is seated on the tubing hanger in the large four-way of the thermal recovery wellhead through the hanging rod short joint, so as to achieve steam injection with the pump without lifting the sucker rod string and safely hanging the rod.

[0057] Steam enters the steam injection and oil production channel in the integrated pipe column of the present invention through the insulation pipe 9. Under the action of steam pressure, the conversion valve ball of the steam injection and oil production conversion switch 6 moves upward, and its upper valve ball 68 closes the liquid flow channel 67 between the steam injection and oil production channel and the casing annulus. The steam can only move downward and enter the oil layer from the sand control screen pipe 2.

[0058] D. Use the steam injection oil production channel to produce oil: When oil production is carried out, the formation liquid enters the sand control pipe string dropped in the casing from the sand control screen 2, and goes up into the steam injection oil production channel in the integrated pipe string. Under the action of the well fluid pressure, the conversion valve ball in the steam injection oil production conversion switch 6 goes up, and the upper valve ball 68 closes the liquid flow channel 67 between the steam injection oil production channel and the casing annulus. The formation liquid can only go up and is lifted to the ground by the rod pump 7.

[0059] E. Use the well-washing circulation channel to wash the well: When well-washing construction is required during the production process, liquid is pumped into the casing annulus from the wellhead casing valve. The downward movement of the liquid pushes the conversion valve ball in the steam injection and oil production conversion switch 6 downward, and the upper valve ball 68 is separated from the upper ball seat in the liquid flow channel 67, so that the liquid flow channel 67 between the steam injection and oil production channel and the casing annulus is connected; at the same time, the lower valve ball 63 closes the channel below the lower ball matching seat 61 in the steam injection and oil production conversion switch 6, and the well-washing liquid can only be returned from the steam injection and oil production channel above the steam injection and oil production conversion switch 6, thereby realizing the circulation well-washing function and the function of preventing the downward movement of the well-washing liquid from causing damage to the oil layer.

[0060] The embodiments described above are only typical embodiments, but the present invention is not limited to these embodiments, and those skilled in the art can make modifications without departing from the spirit and enlightenment of the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. Any modifications, equivalent replacements, improvements, etc. made within the creative spirit and creative concept of the present invention should be included in the protection scope of the present invention. Therefore, the protection scope is not limited to the above description.

Claims

1. An integrated sand control and steam injection oil production string, comprising a sand control string, a steam injection oil production string and a sucker rod string, wherein the sand control string is provided with a threaded plug (1), a sand control screen (2) and a sand control steam injection packer (4), the steam injection oil production string is formed by connecting a heat insulating pipe (9) with a pump seat of a rod-type oil pump (7), the heat insulating pipe (9) can hang the steam injection oil production string on the oil pipe hanger in the wellhead big four-way, the piston of the rod-type oil pump (7) is connected to the lower end of the hollow rod (8) to form the sucker rod string, the piston of the rod-type oil pump (7) is mounted together with the pump seat of the rod-type oil pump (7), and the characteristics are: An insulating compensator outer tube (3) is installed between the sand control screen tube (2) and the sand control steam injection packer (4) in the sand control pipe string; the pump seat of the rod-type oil pump (7) at the lower end of the steam injection oil production pipe string is connected to the steam injection oil production conversion switch (6) and the insulating compensator plug pipe (5) in sequence; the steam injection oil production conversion switch (6) is provided with a liquid flow channel (67) and a conversion valve ball is installed in the liquid flow channel (67); the conversion valve ball includes an upper valve ball (68), a valve ball connecting rod (66) and a lower valve ball (63), and the upper valve ball (68) and the lower valve ball (63) are connected to each other. connected to both ends of the valve ball connecting rod (66); the thermal insulation compensator insert (5) can pass through the inner channel of the anti-sand steam injection seal (4) and be inserted into the outer tube (3) of the thermal insulation compensator to form a steam injection and oil production channel with the liquid flow channel (67) in the steam injection and oil production conversion switch (6); the liquid flow channel (67) can be connected to the oil casing annulus to form a well washing circulation channel; the conversion valve ball in the liquid flow channel (67) can simultaneously close the well washing circulation channel and open the steam injection and oil production channel, or simultaneously open the well washing circulation channel and close the steam injection and oil production channel.

2. The sand control steam injection and oil production integrated pipe string as claimed in claim 1, characterized in that: The steam injection and oil production conversion switch (6) is further provided with a switch body (60), a lower ball fitting seat (61), a connecting sleeve (64) and a switch upper joint (69), wherein: the liquid flow passage (67) is arranged in the switch upper joint (69), and the connecting sleeve (64) is threadedly connected to the lower part of the switch upper joint (69); the lower ball fitting seat (61) is located below the connecting sleeve (64), and the switch body (60) and the switch upper joint (69) are threadedly connected to fix the connecting sleeve (64) in the switch body (60); the upper valve ball (68) is installed in the liquid flow passage (67) of the switch upper joint (69), and the lower valve ball (63) is installed in the lower ball fitting seat (61) below the connecting sleeve (64).

3. The sand control steam injection and oil production integrated pipe string as claimed in claim 2, characterized in that: The upper valve ball (68) mounted on the upper end of the valve ball connecting rod (66) is a conical sphere and can cooperate with the upper ball seat in the liquid flow channel (67); the lower valve ball (63) mounted on the lower end of the valve ball connecting rod (66) is composed of a lower sphere and a fixing cap, and the lower sphere is inserted under the limit platform at the lower part of the valve ball connecting rod (66) and fixed by the fixing cap threadedly connected to the valve ball connecting rod (66).

4. The sand control steam injection and oil production integrated pipe string as claimed in claim 3, characterized in that: The liquid flow channel (67) and the conversion valve ball arranged in the switch upper joint (69) are arranged in more than three sets; the upper end of the liquid flow channel (67) is connected to the outer wall of the switch upper joint (69), the inner side is connected to the central hole of the switch upper joint (69), the lower end is connected to the central hole of the connecting sleeve (64) and the liquid flow hole in the lower ball matching seat (61), and is connected to the central hole of the switch body (60) through the liquid flow hole in the lower ball matching seat (61).

5. The sand control steam injection and oil production integrated pipe string as claimed in claim 4, characterized in that: The lower ball fitting seat (61) is provided with liquid flow holes corresponding to the number and position of the liquid flow channel (67) and the conversion valve ball, and a middle partition is provided in the inner cavity of the body of the lower ball fitting seat (61), and the liquid flow holes are processed on the outer periphery of the middle partition; a tapered hole with a larger top and a smaller bottom is processed on the upper part of the liquid flow hole to serve as the lower ball seat, and a sealing member (62) is provided on the outer wall of the lower ball fitting seat (61).

6. The sand control steam injection and oil production integrated pipe string as claimed in claim 5, characterized in that: The lower body of the lower sphere in the lower valve ball (63) is provided with an assembly groove and a center hole, and the lower outer wall is in an inverted cone shape, which can be matched with the lower ball seat in the lower ball matching seat (61); the outer diameter formed by the fixing cap in the lower valve ball (63) is smaller than the inner diameter of the liquid flow hole in the lower ball matching seat (61) that passes through the lower ball seat; the fixing cap in the lower valve ball (63) can be installed in the assembly groove of the lower sphere.

7. The sand control, steam injection and oil production integrated pipe string as claimed in claim 6, characterized in that A straightening ring (65) is installed at the bottom of the liquid flow channel (67) in the upper switch connector (69). The center hole of the straightening ring (65) is concentric and has the same diameter as the center hole of the upper switch connector (69), and a body outside the center hole of the straightening ring (65) is provided with valve ball connecting rod passing holes, the same number as the conversion valve ball; the outer diameter of the straightening ring (65) is larger than the inner diameter of the center hole of the connecting sleeve (64), and the inner diameter of the center hole of the connecting sleeve (64) is smaller than the outer diameter formed by the lower sphere in the lower valve ball (63).

8. The sand control steam injection and oil production integrated pipe string as claimed in claim 7, characterized in that: The switch body (60) is a non-uniform cylindrical body and the upper body cavity is provided with an internal thread that can be threadedly connected to the switch upper joint (69), and a sealing ring is also installed above the threaded connection section between the switch body (60) and the switch upper joint (69); the lower inner cavity of the switch body (60) is provided with a lower ball fitting seat assembly step, and the lower ball fitting seat (61) is installed on the lower ball fitting seat assembly step; the external thread at the lower part of the switch body (60) can be threadedly connected to the insulation compensator plug (5), and the internal thread in the upper inner cavity of the switch upper joint (69) can be threadedly connected to the pump seat lower joint of the rod-type oil pump (7).

9. The sand control steam injection and oil production integrated pipe string as claimed in claim 1, characterized in that: The sand control steam injection packer is a 445 type packer.

10. A method for using a sand control, steam injection and oil production integrated pipe string as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: A. Run the sand control string and drop the hands into the casing; B. Lower the steam injection production tubing string and the sucker rod string; C. Use the steam injection production tubing string to inject steam; D. Use the steam injection production channel to produce oil; E. Use the well washing circulation channel to wash the well.

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