Process pipe column suitable for water injection well of lifting oil layer

Abstract

The invention relates to the technical field of oil field water injection well downhole operation, in particular to a process pipe column suitable for a water injection well of a lifting oil layer. The process pipe column suitable for the water injection well of the lifting oil layer comprises a casing pipe, an oil pipe penetrates through the casing pipe, and a blowout prevention working barrel, a production pipe column and a multifunctional blowout prevention tail pipe are sequentially arranged below the oil pipe. A blowout prevention inner plug is arranged in the blowout prevention working barrel, and the blowout prevention inner plug and the blowout prevention working barrel are matched to open an oil sleeve channel. The production pipe column comprises a plurality of matched packers with midway setting prevention design, the matched packers divide the production pipe column into a plurality of layers, and each layer is provided with an anti-backflow water distributor with a one-way valve function. And meanwhile, the problems of midway setting of the packer, dead water nozzle casting of the water distributor and the like are solved, so that a pipe column can be safely lifted and lowered in the operation process, certain casting and fishing workload can be reduced, and the operation efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of downhole operation of water injection wells in oil fields, and in particular to a process pipe string suitable for water injection wells in Fuyang oil layers. Background Art

[0002] At present, the Fuyang oil layer in the oil field has the special characteristics of deep burial, high pressure and temperature. The burial depth of the oil layer ranges from 1400 to 2000 meters, the temperature of the oil layer ranges from 81 to 88°C, the injection pressure at the wellhead is 17 to 20MPa, and the downhole pressure is above 30MPa. Although it does not meet the definition of a high-temperature and high-pressure well, it also has the characteristics of high bottom hole temperature and high pressure compared to the Sap oil layer. The Sap oil layer injection process string consists of a compression packer, a bridge water distributor, a ball screen pipe guide cone, etc. It is suitable for downhole environments with a working pressure of 15MPa and a working temperature of 70°C, and the technology application is mature.

[0003] There is no special injection string for Fuyang oil layer. The high temperature and high pressure packers on the market are suitable for high temperature and high pressure wells with pressure higher than 70MPa and well temperature higher than 150℃, but they are expensive. At present, there are two main development methods. One is to use the injection string for Sap oil layer, but the original structure of the packer is replaced with high temperature and high pressure resistant rubber elements, which will cause the problem of oil casing imbalance during water injection development; the other is to use the water injection string composed of expansion packer and bridge eccentric water distributor, which will cause the casing packer to be unsealed during application. Summary of the invention

[0004] 1. Technical issues to be solved:

[0005] The present invention provides a process pipe string suitable for water injection wells in Fuyang oil layer, so as to overcome the problems in the prior art that the material used cannot withstand high temperature and high pressure, the oil casing is unbalanced, the casing sealer is not sealed, etc., and at the same time, avoid the phenomenon of the pipe string being easily pushed up and the pipe string being swayed due to the pressure from the bottom during the well running process.

[0006] (II) Technical solution:

[0007] In order to solve the above problems, the present invention provides a process pipe string suitable for water injection wells in Fuyang oil layer, comprising: a casing, an oil pipe is passed through the casing, and a blowout prevention working cylinder, a production pipe string and a multifunctional blowout prevention tail pipe are arranged in sequence below the oil pipe;

[0008] The blowout prevention working cylinder is provided with a blowout prevention inner plug, and the blowout prevention inner plug and the blowout prevention working cylinder cooperate to open the oil casing channel;

[0009] The production string includes a plurality of matching packers to separate the production string into several layers, and each layer is provided with an anti-backflow water distributor.

[0010] Preferably, the blowout prevention working cylinder includes a sliding sleeve, and a sliding sleeve retaining spring seat is provided above the sliding sleeve; the sliding sleeve is installed in the outer sleeve after being connected to the sliding sleeve retaining spring seat; a sliding sleeve upper joint is provided above the sliding sleeve retaining spring seat, the sliding sleeve upper joint is threadedly connected to the upper end of the outer sleeve, and the lower end is threadedly connected to the sliding sleeve lower joint; the sliding sleeve and the outer sleeve are fixed by a fixing pin; a sliding sleeve retaining spring is provided on the outside of the top end of the sliding sleeve; a horse tooth buckle is provided inside the outer sleeve, and a jacket liquid outlet is provided at the corresponding part between the outer sleeve and the sliding sleeve groove.

[0011] Preferably, the blowout-proof inner plugging comprises an expanding sleeve, a blowout-proof inner plugging sealing sleeve is connected below the expanding sleeve, an inner plugging connecting sleeve is connected below the blowout-proof inner plugging sealing sleeve, and a conical head is connected below the inner plugging connecting sleeve; a spring claw is provided on the top of the expanding sleeve; the interior of the inner plugging connecting sleeve is threadedly connected to the blowout-proof valve assembly; a movable ball seat is fixed in the inner plugging connecting sleeve by a ball seat pin, and an inner plugging steel ball is provided above the movable ball seat; an inner plugging liquid outlet is provided on the part of the inner plugging connecting sleeve corresponding to the lower part of the movable ball seat; and a plurality of blowout-proof inner plugging sealing rings are provided on the blowout-proof inner plugging sealing sleeve.

[0012] Preferably, the matching packer comprises a packer center pipe, the upper end of the packer center pipe is connected to the packer upper joint, and the packer upper jacket is provided outside the packer upper joint; the lower end of the packer center pipe is connected to the packer lower joint, and the packer lower jacket is provided outside the packer lower joint;

[0013] An upper well-washing piston is provided between the upper outer sleeve of the packer and the center tube of the packer, and the upper well-washing piston can move up and down, and the lower end of the upper well-washing piston is connected to the well-washing piston; an outer center tube is provided outside the center tube of the packer, and a first side hole of the center tube and a second side hole of the center tube are provided at the upper and lower ends of the outer center tube;

[0014] The inner side of the lower end of the upper outer sleeve of the packer is threadedly connected to the upper stop ring of the rubber cylinder, the lower stop ring of the rubber cylinder is connected below the upper stop ring of the rubber cylinder, and a rubber cylinder assembly is provided between the upper stop ring of the rubber cylinder and the lower stop ring of the rubber cylinder;

[0015] The lower stop ring of the rubber cylinder is fixed on the retaining spring fixing sleeve by a setting pin, and the retaining spring fixing sleeve is threadedly connected to the center tube of the packer; the retaining spring fixing sleeve is fixed on the unsealing sleeve by an unsealing pin, and the unsealing sleeve is threadedly connected to the retaining spring fastening sleeve, and a groove is provided between the retaining spring fixing sleeve and the retaining spring fastening sleeve, and a retaining spring is provided in the groove;

[0016] A circlip hanger is provided below the outer side of the lower stop ring of the rubber cylinder, and a horse tooth buckle is provided inside the circlip hanger; the lower outer sleeve of the packer is connected below the circlip hanger;

[0017] An annular space is provided between the center pipe of the packer, the lower outer sleeve of the packer and the lower joint of the packer, and an upper setting piston, a piston transition and a lower setting piston are provided in the annular space; the upper setting piston is installed on a boss at the lower end of the retaining spring;

[0018] The center tube of the packer is provided with a first through hole corresponding to the position between the upper outer sleeve of the packer and the upper well washing piston, the center tube of the packer is provided with a second through hole corresponding to the position between the upper setting piston and the piston transition, and the center tube of the packer is provided with a third through hole corresponding to the position between the lower setting piston and the lower joint of the packer.

[0019] Preferably, the anti-backflow water distributor comprises an eccentric body, a biased hole is provided in the eccentric body, and a plug is provided in the biased hole; a ceramic ball is provided in the water nozzle of the plug, and the diameter of the ceramic ball matches the inner diameter of the plug to form a one-way valve structure;

[0020] The upper part of the eccentric body is connected to the straightening body, and the upper part of the water distributor is provided on the straightening body; the upper connecting sleeve of the water distributor is provided on the straightening body, the upper end of the upper connecting sleeve of the water distributor is connected to the upper joint of the water distributor, the lower end of the upper connecting sleeve of the water distributor is connected to the eccentric body, the lower end of the eccentric body is connected to the lower connecting sleeve of the water distributor, and the lower part of the lower connecting sleeve of the water distributor is connected to the lower joint of the water distributor;

[0021] A lower guide body is arranged in the lower joint of the water distributor, a guide sleeve is arranged between the upper joint of the water distributor and the straightening body, and an upper guide body is arranged in the guide sleeve.

[0022] Preferably, the multifunctional blowout-preventing tail pipe comprises a sleeve, the upper inner side of the sleeve is threadedly connected to the upper sliding sleeve of the blowout-preventing tail pipe through a connecting piece, the upper sliding sleeve of the blowout-preventing tail pipe is connected to the upper joint of the blowout-preventing tail pipe through a fixing piece, the lower inner side of the sleeve is connected to the lower sliding sleeve of the blowout-preventing tail pipe, and a spring is provided between the connecting piece and the lower sliding sleeve of the blowout-preventing tail pipe; a first side hole of the fixing piece is provided on the fixing piece, and the bottom of the fixing piece is a spring claw structure; a baffle and a steel ball are provided inside the fixing piece, and the baffle is provided with a plurality of liquid holes.

[0023] Preferably, the upper sliding sleeve of the blowout-proof tail pipe is connected to the inner side of the fixing part and is threadedly connected to the baffle; the upper sliding sleeve of the blowout-proof tail pipe moves relative to the fixing part; a limit block is provided on the fixing part, and the upper sliding sleeve of the blowout-proof tail pipe is limited to move downward by the limit block; a conical surface is provided on the surface of the upper sliding sleeve of the blowout-proof tail pipe, and a steel ball is arranged between the baffle and the upper sliding sleeve of the blowout-proof tail pipe, and a second side hole of the fixing part equal to the first side hole of the fixing part on the fixing part is provided on the upper sliding sleeve of the blowout-proof tail pipe;

[0024] The top and bottom of the sleeve are respectively provided with circular grooves to fix the spring claws of the fixing member, the lower end of the lower sleeve of the blowout-proof tail pipe is provided with a liquid inlet hole, and the boss at the bottom end of the outer sleeve limits the downward movement of the lower sleeve of the blowout-proof tail pipe.

[0025] (III) Beneficial effects:

[0026] The present invention provides a process pipe string suitable for a water injection well in the Fuyang oil layer, which realizes the plugging function of the liquid in the pipe string at the lower end of the tool section by cooperating with a blowout prevention working tube and a blowout prevention inner plug; the water injection pipe string is smoothly lowered into the expected position by a matching packer; the backflow prevention water distributor ensures that the discharge balance pressure can be achieved in the entire pipe string without jetting overflow; and a second blowout prevention is realized before the pipe string is lifted by a multifunctional blowout prevention tail pipe.

[0027] The present invention can realize primary and secondary pipe blowout prevention during operation, and solve the problems of mid-course setting of the packer and dead water nozzle of the water distributor. It can not only realize safe lifting and lowering of the pipe during operation, but also reduce a certain amount of lifting and salvaging workload and improve operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the overall structure of a process string for a water injection well in the Fuyang oil layer according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of a blowout prevention working cylinder according to an embodiment of the present invention;

[0030] Figure 3 This is a structural diagram of the blowout prevention inner plugging according to an embodiment of the present invention;

[0031] Figure 4 This is a structural diagram of a packer supporting an embodiment of the present invention;

[0032] Figure 5 This is a structural diagram of an anti-backflow water distributor according to an embodiment of the present invention;

[0033] Figure 6 This is a structural diagram of a multifunctional blowout-preventing tail pipe according to an embodiment of the present invention.

[0034] Among them, 1-casing; 2-oil pipe; 3-blowout prevention working cylinder; 4-matching packer; 5-anti-backflow water distributor; 6-multi-functional blowout prevention tail pipe; 7-sleeve upper joint; 8-outer sleeve; 9-sleeve retaining spring; 10-sleeve retaining spring seat; 11-sleeve; 12-fixing pin; 13-sleeve lower joint; 14-expansion sleeve; 15-blowout prevention inner plugging sealing sleeve; 16-blowout prevention valve assembly; 17-blowout prevention inner plugging sealing ring; 18-inner plugging steel ball; 19-movable ball seat; 20-ball seat pin; 21-inner plugging connecting sleeve; 22-conical head; 23-packer upper joint; 24-packer center pipe; 25-packer upper outer sleeve; 26-upper well washing piston; 27-well washing piston; 28-rubber cylinder upper retaining ring; 29-outer center pipe; 30-rubber cylinder assembly; 31-rubber cylinder lower retaining ring; 32- Setting pin; 33-circlip fixing sleeve; 34-unsealing pin; 35-unsealing sleeve; 36-circlip; 37-circlip fastening sleeve; 38-circlip hanger; 39-upper setting piston; 40-piston transition; 41-lower outer sleeve of packer; 42-lower setting piston; 43-lower joint of packer; 44-upper joint of water distributor; 45-guide sleeve; 46-upper guide body; 47-upper connecting sleeve of water distributor; 48-rightening body; 49-plug; 50-ceramic ball; 51-eccentric body; 52-lower connecting sleeve of water distributor; 53-lower joint of water distributor; 54-lower guide body; 55-upper joint of blowout-proof tail pipe; 56-baffle; 57-fixing piece; 58-steel ball; 59-upper sliding sleeve of blowout-proof tail pipe; 60-connecting piece; 61-sleeve; 62-spring; 63-lower sliding sleeve of blowout-proof tail pipe. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 creative work are within the scope of protection of the present invention.

[0036] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by “upper”, “lower”, “inside”, “outside”, “top”, “bottom”, etc. are all based on the orientations or positional relationships shown in the accompanying drawings. The purpose is only to facilitate the description of the present invention and simplify the description. It does not indicate or imply that the referred parts must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0037] like Figure 1-6 As shown, the present invention provides a process pipe string suitable for the Fuyang oil layer water injection well, specifically comprising: a casing 1, an oil pipe 2 is passed through the casing 1, and a blowout prevention working cylinder 3, a production pipe string and a multifunctional blowout prevention tail pipe 6 are arranged below the oil pipe 2 in sequence.

[0038] Among them, the blowout prevention working cylinder 3 is provided with a blowout prevention inner plug, and the blowout prevention inner plug and the blowout prevention working cylinder 3 cooperate to open the oil casing channel; the production tubing string includes a plurality of matching packers 4 to separate the production tubing string into several layers, and each layer is provided with an anti-backflow water distributor 5.

[0039] like Figure 2 As shown, the blowout prevention working cylinder 3 includes a sleeve 11, and a sleeve retaining spring seat 10 is provided above the sleeve 11; the sleeve 11 is connected to the sleeve retaining spring seat 10 and then installed in the outer sleeve 8; a sleeve upper joint 7 is provided above the sleeve retaining spring seat 10, and the sleeve upper joint 7 is threadedly connected to the upper end of the outer sleeve 8 for connecting the oil pipe 2; the sleeve 11 and the outer sleeve 8 are fixed by a fixing pin 12, and when the downward force applied to the sleeve 11 exceeds the stress limit of the fixing pin 12, the fixing pin 12 is cut off, and the sleeve 11 moves downward; a sleeve lower joint 13 is provided below the sleeve 11 for connecting with the components below.

[0040] Among them, the diameter of the side of the sleeve 11 is smaller than the diameter of the two ends, and a groove is formed on the side of the sleeve 11; the lower end of the outer sleeve 8 is connected to the sleeve lower joint 13, and a cavity is provided between the sleeve lower joint 13 and the sleeve 11 in the outer sleeve 8, and the diameter of the cavity is larger than the diameter of the sleeve 11. When the sleeve 11 moves downward, part of the groove enters the cavity with the sleeve 11 moving downward; the side of the outer sleeve 8 is provided with an outer sleeve liquid outlet hole, and when the groove enters the cavity, the outer sleeve liquid outlet hole coincides with part of the groove, and at the same time, the bottom of the sleeve 11 still does not contact the sleeve lower joint 13, at this time, the inside of the blowout preventer working cylinder 3 is connected with the oil casing annulus to establish a liquid flow channel.

[0041] It should be noted that a sleeve retaining spring 9 is provided on the outside of the top of the sleeve 11, and a tooth buckle is provided on the inside of the outer sleeve 8. When the sleeve 11 moves downward, the sleeve retaining spring 9 cooperates with the tooth buckle to fix the sleeve 11. At this time, there is still a distance between the bottom of the sleeve 11 and the top of the sleeve upper joint 7, thereby ensuring the stability and normal operation of the liquid flow channel.

[0042] like Figure 3 As shown, the blowout-proof inner plug is arranged in the blowout-proof working cylinder 3, and the blowout-proof inner plug comprises an expansion sleeve 14, and a spring claw is arranged on the top of the expansion sleeve 14, and a blowout-proof inner plug sealing sleeve 15 is connected to the bottom of the expansion sleeve 14, and a plurality of blowout-proof inner plug sealing rings 17 are arranged on the blowout-proof inner plug sealing sleeve 15 to ensure the sealing performance of the device; the blowout-proof inner plug sealing sleeve 15 is connected to the inner plug connecting sleeve 21 below, and the inner plug connecting sleeve 21 is connected to the conical head 22 below, and the inner plug connecting sleeve 21 is threadedly connected to the blowout-proof valve assembly 16 inside; the upper end of the blowout-proof valve assembly 16 is an upward cone, and the lower end surface of the blowout-proof inner plug sealing sleeve 15 cooperates with the top of the blowout-proof valve assembly 16 to form a one-way valve structure, when the liquid flows from top to bottom, it can flow freely, and when the liquid moves from bottom to top, the blowout-proof valve assembly 16 moves upward and cooperates with the inner plug connecting sleeve 21 to prevent the liquid from flowing upward.

[0043] It should be noted that the movable ball seat 19 is fixed in the inner blocking connecting sleeve 21 by a ball seat pin 20, and an inner blocking steel ball 18 is provided above the movable ball seat 19. The upper surface of the movable ball seat 19 cooperates with the inner blocking steel ball 18 to form a single-flow valve structure. When the liquid flows from top to bottom, the inner blocking steel ball 18 prevents the flow of liquid.

[0044] Among them, the inner plugging connecting sleeve 21 is provided with an inner plugging liquid outlet hole corresponding to the part below the movable ball seat 19. After the liquid flow channel is established in the blowout preventer working cylinder 3, the pressurization continues. When the liquid pressure on the inner plugging steel ball 18 is greater than the stress limit of the ball seat pin 20, the ball seat pin 20 is cut off, and the movable ball seat 19 moves downward. At this time, the inner plugging liquid outlet hole on the inner plugging connecting sleeve 21 is connected with the inside of the blowout preventer inner plug to form a liquid channel. When the tubing string is lifted afterwards, the liquid in the oil tubing string enters the oil casing annulus through the blowout preventer inner plug and the blowout preventer working cylinder 3, forming an anti-blocking and anti-splashing structure.

[0045] It should be noted that the blowout preventer inner plug and the blowout preventer working barrel 3 are designed as a separate body. At the beginning of the work, the blowout preventer inner plug is not installed on the blowout preventer working barrel 3. Before the pipe string is to be operated, the valve at the wellhead is opened to drop the blowout preventer inner plug. Under the push of the water injection pressure, the blowout preventer inner plug moves downward, contacts the blowout preventer working barrel 3 and works.

[0046] like Figure 4 As shown, the matching packer 4 includes a packer center tube 24, the upper end of which is connected to the packer upper joint 23, and a packer upper outer sleeve 25 is provided outside the packer upper joint 23; the lower end of the packer center tube 24 is connected to the packer lower joint 43, and a packer lower outer sleeve 41 is provided outside the packer lower joint 43; an upper well washing piston 26 is provided between the packer upper outer sleeve 25 and the packer center tube 24, and the upper well washing piston 26 can move up and down, and the lower end of the upper well washing piston 26 is connected to the well washing piston 27; the packer center tube 24 is provided with an outer center tube 29, and a center tube first side hole and a center tube second side hole are provided at the upper and lower ends of the outer center tube 29.

[0047] Among them, the inner side of the lower end of the upper sleeve 25 of the packer is threadedly connected with the upper stop ring 28 of the rubber cylinder, and the lower stop ring 31 of the rubber cylinder is connected below the upper stop ring 28 of the rubber cylinder, and a rubber cylinder assembly 30 is provided between the upper stop ring 28 of the rubber cylinder and the lower stop ring 31 of the rubber cylinder; the lower stop ring 31 of the rubber cylinder is fixed on the retaining spring fixing sleeve 33 through the setting pin 32, and the retaining spring fixing sleeve 33 is threadedly connected with the center tube 24 of the packer; the retaining spring fixing sleeve 33 is fixed on the unsealing sleeve 35 through the unsealing pin 34, and the unsealing sleeve 35 is threadedly connected with the retaining spring fastening sleeve 37, and a groove is provided between the retaining spring fixing sleeve 33 and the retaining spring fastening sleeve 37, and a retaining spring 36 is provided in the groove; a retaining spring hanger 38 is provided at the lower outer side of the lower stop ring 31 of the rubber cylinder, and a horse tooth buckle is provided on the inner side of the retaining spring hanger 38; the retaining spring hanger 38 is connected to the lower sleeve 41 of the packer below.

[0048] It should be noted that an annular space is provided between the center tube 24 of the packer, the lower outer sleeve 41 of the packer and the lower joint 43 of the packer, and an upper seating piston 39, a piston transition 40 and a lower seating piston 42 are provided in the annular space; the upper seating piston 39 is installed on a boss at the lower end of the retaining spring hanger 38; the center tube 24 of the packer is provided with a first through hole corresponding to a position between the upper outer sleeve 23 of the packer and the upper well washing piston 26, the center tube 24 of the packer is provided with a second through hole corresponding to a position between the upper seating piston 39 and the piston transition 40, and the center tube 24 of the packer is provided with a third through hole corresponding to a position between the lower seating piston 42 and the lower joint 43 of the packer.

[0049] In actual application, high-pressure liquid enters the annulus between the center tube 24 of the packer, the upper outer sleeve 23 of the packer and the upper well washing piston 26 through the first through hole, enters the annulus between the center tube 24 of the packer, the upper sealing piston and the piston transition 40 through the second through hole, and enters the annulus between the center tube 24 of the packer, the lower sealing piston 42 and the lower joint 43 of the packer through the third through hole; at this time, the liquid pressure pushes the piston transition 40 to push the upper sealing piston 39 and the lower sealing piston 42 to move upward, and the upper sealing piston 39 and the lower sealing piston 42 push the retaining spring hanger 38 to move upward, cut off the sealing pin 32, and continue to compress the rubber sleeve assembly 30. When the rubber sleeve assembly 30 reaches the compressed state, the retaining spring 36 enters the tooth buckle of the retaining spring hanger 38 to lock the rubber sleeve assembly 30, and the matching packer 4 is sealed.

[0050] It should be noted that the sealing pin 32 has the function of preventing mid-sealing during the working process. Only when the pressure is greater than its maximum shear stress, the sealing pin 32 is sheared off, and the rubber cylinder assembly 30 can perform normal sealing work, ensuring that mid-sealing will not occur during the lowering of the device, and ensuring that the device can be smoothly lowered to the sealing position.

[0051] like Figure 5As shown, the anti-backflow water distributor 5 includes an eccentric body 51, a biased hole is provided in the eccentric body 51, and a plug 49 is provided in the biased hole; a ceramic ball 50 is provided in the water nozzle of the plug 49, and the diameter of the ceramic ball 50 cooperates with the inner diameter of the plug 49 to form a single-flow valve structure.

[0052] Among them, the eccentric body 52 is connected to the straightening body 48 above, and the water distributor upper joint 44 is provided above the straightening body 48; the water distributor upper connecting sleeve 47 is provided outside the straightening body 48, the upper end of the water distributor upper connecting sleeve 47 is connected to the water distributor upper joint 44, the lower end of the water distributor upper connecting sleeve 47 is connected to the eccentric body 51, the lower end of the eccentric body 51 is connected to the water distributor lower connecting sleeve 52, and the lower end of the water distributor lower connecting sleeve 52 is connected to the water distributor lower joint 53.

[0053] In practical applications, the ceramic ball 50 matches the inner surface of the water inlet of the plug 49. When the device injects water through the plug 49, the liquid enters the surrounding annulus through the water nozzle of the plug 49; at the same time, when the liquid in the annulus flows back, the ceramic ball 50 is pushed by the liquid to block the water inlet of the plug 49, preventing the liquid from flowing back and forming a check valve structure. The above structure allows the anti-backflow water distributor 5 to both inject water normally and prevent liquid from flowing back to play a role in preventing spraying.

[0054] like Figure 6 As shown, the multifunctional blowout-preventing tail pipe 6 includes a sleeve 61, the upper inner side of the sleeve 61 is threadedly connected to the blowout-preventing tail pipe upper sliding sleeve 59 through a connecting piece 60, the upper side of the blowout-preventing tail pipe upper sliding sleeve 59 is connected to the blowout-preventing tail pipe upper joint 55 through a fixing piece 57, the lower inner side of the sleeve 61 is connected to the lower sliding sleeve 63 of the blowout-preventing tail pipe, and a spring 62 is provided between the connecting piece 60 and the lower sliding sleeve 63 of the blowout-preventing tail pipe; a first side hole of the fixing piece 57 is provided on the fixing piece 57, and the bottom of the fixing piece 57 is a spring claw structure; a baffle 56 and a steel ball 58 are provided in the fixing piece 57, and the baffle 56 is provided with a plurality of liquid holes.

[0055] Among them, the upper sliding sleeve 59 of the blowout-proof tail pipe is connected to the inner side of the fixing part 57 and is threadedly connected to the baffle; the upper sliding sleeve 59 of the blowout-proof tail pipe moves relative to the fixing part 57; there is a limit block on the fixing part 57, and the upper sliding sleeve 59 of the blowout-proof tail pipe is limited to move downward by the limit block; the surface of the upper sliding sleeve 59 of the blowout-proof tail pipe is provided with a conical surface, and the steel ball 58 is arranged between the baffle 56 and the upper sliding sleeve 59 of the blowout-proof tail pipe, and the upper sliding sleeve 59 of the blowout-proof tail pipe is provided with a second side hole of the fixing part equal to the first side hole of the fixing part on the fixing part 57.

[0056] It should be noted that circular grooves are provided at the top and bottom of the sleeve 61 to fix the spring claws of the fixing member 57, a liquid inlet hole is provided at the lower end of the lower sleeve 63 of the blowout-proof tail pipe, and a boss at the bottom end of the outer sleeve 61 limits the downward movement of the lower sleeve 63 of the blowout-proof tail pipe.

[0057] In actual application, during the process of lowering the tubing string, the downhole pressure pushes the lower sleeve 63 of the blowout preventer tail pipe to move upward, and the liquid in the liquid inlet hole of the lower sleeve 63 of the blowout preventer tail pipe is transmitted to the pipe. The liquid pressure pushes the steel ball 58 to float up, and the liquid enters the tubing string. Due to the reaction force of the spring 62 and the aperture of the liquid inlet hole of the lower sleeve 63 of the blowout preventer tail pipe, the amount of liquid entering the tubing string is in a slow-moving state, and the tubing string always keeps the liquid in and does not overflow.

[0058] When the pipe string continues to go down to the predetermined position, the oil pipe is pressurized. At this time, the steel ball 58 fits on the conical surface of the sliding sleeve 59 on the blowout tail pipe to form a plug, which is convenient for building pressure in the pipe string to seal the packer. All parts except the joint 55 and the fixing member 57 on the blowout tail pipe move downward. The limit block of the fixing member 57 limits the sliding sleeve 59 on the blowout tail pipe to continue to move downward. The spring claw of the fixing member 3 and the upper groove and lower groove of the sleeve 8 are switched to realize the switch between the blowout prevention and the one-way valve and the one-way valve and the blowout prevention; the first side hole on the fixing member 57 coincides with the second side hole on the sliding sleeve 59 on the blowout tail pipe. At this time, the oil casing is connected, and the injection well is injected and backwashed normally.

[0059] Before the pipe string is raised again, the secondary blowout prevention function of the present invention is triggered by deepening the well and touching the bottom of the artificial well. The spring claw of the fixing member 57 disengages from the upper groove of the sleeve 61, and all parts except the upper joint 55 and the fixing member 57 of the blowout prevention tail pipe move upward until the spring claw of the fixing member 57 is stuck in the lower groove of the sleeve 8. At this time, the first side hole on the fixing member 57 is staggered with the second side hole on the sliding sleeve 59 on the blowout prevention tail pipe. Therefore, during the pipe string raising process, the injection pipe string can still have the blowout prevention function, which can enhance the overall safety of the pressure operation during the construction process.

[0060] It should be noted that the contacting parts between the components in the present invention are provided with a plurality of sealing rings to ensure the sealing of the device during use, ensure the normal operation of the device, and improve the practicality of the device.

[0061] The following is a detailed description of the working principle of this process string suitable for water injection wells in the Fuyang oil layer:

[0062] In actual application, the device is connected to the oil pipe and various components from bottom to top in sequence, and the assembled pipe string is lowered into the well. During the process of lowering the pipe string, the multifunctional blowout preventer tail pipe 6 is initially in a non-fully sealed state, and the liquid in the wellbore can slowly enter the pipe string. The downhole pressure pushes the lower sleeve 63 of the blowout preventer tail pipe to move upward, and the well fluid is transmitted to the pipe through the liquid inlet hole of the lower sleeve 63 of the blowout preventer tail pipe. The liquid pressure pushes the steel ball 58 to float up, and the liquid enters the pipe string. Limited by the reaction force of the spring 62 and the aperture of the liquid inlet hole of the lower sleeve 63 of the blowout preventer tail pipe, the amount of liquid entering the pipe string is in a slow-advancing state, and the pipe string always keeps the liquid filling and non-overflowing state.

[0063] At this time, the ceramic ball 50 in the plug 49 in the anti-backflow water distributor 5 is sealed on the conical surface in the sealing section by the pressure of the well fluid outside the pipe column, blocking the well fluid from entering the pipe column through the plug 49 and preventing the liquid in the pipe column from overflowing.

[0064] It should be noted that when the pipe string is lowered to the predetermined position, the oil pipe is pressurized, and the steel ball 58 is attached to the conical surface of the sliding sleeve 59 on the blowout tail pipe to form a plug, which is convenient for building pressure in the pipe string to seal the packer. All parts except the joint 55 and the fixing member 57 on the blowout tail pipe move downward, and the limit block of the fixing member 57 limits the sliding sleeve 59 on the blowout tail pipe to continue to move downward. The spring claw of the fixing member 3 and the upper groove and lower groove of the sleeve 8 are switched to realize the switch between the blowout prevention and the one-way valve and the one-way valve and the blowout prevention; the first side hole on the fixing member 57 coincides with the second side hole on the sliding sleeve 59 on the blowout tail pipe, and the oil casing is connected, and the injection well is injected and backwashed normally.

[0065] At this time, liquid enters the center tube 24 of the packer in the matching packer 4, and the high-pressure liquid enters the annulus between the center tube 24 of the packer, the upper outer sleeve 23 of the packer and the upper well washing piston 26 through the first through hole, enters the annulus between the center tube 24 of the packer, the upper sealing piston 39 and the piston transition 40 through the second through hole, and enters the annulus between the center tube 24 of the packer, the lower sealing piston 42 and the lower joint 43 of the packer through the third through hole; the high-pressure liquid pushes the piston transition 40, thereby pushing the upper sealing piston 39 and the lower sealing piston 42 upward, and the upper sealing piston 39 and the lower sealing piston 42 push the retaining spring hanger 38 upward, shearing off the sealing pin 32, and continuing to compress the rubber sleeve assembly 30. When the rubber sleeve assembly 30 reaches the compressed state, the retaining spring 36 enters the tooth buckle of the retaining spring hanger 38 to lock the rubber sleeve assembly 30, and the matching packer 4 is sealed.

[0066] Before dismantling the wellhead again, open the wellhead test valve and put in the blowout preventer inner plug. Under the push of the injection pressure, the blowout preventer inner plug moves downward to the blowout preventer working cylinder 3, and then continues to move downward into the blowout preventer working cylinder 3. The expansion sleeve 14 is combined with the sleeve retaining spring seat 10 to fix the blowout preventer inner plug to the blowout preventer working cylinder 3. The high-pressure liquid pushes the inner plugging steel ball 18 and the movable ball seat 19 to push the blowout preventer inner plug to drive the sleeve 11 downward. The fixing pin 20 is cut off, and the sleeve 11 continues to move downward. The sleeve retaining spring 9 is in contact with the horse in the outer sleeve 8. The threaded buckle fits to fix the sliding sleeve 11. At this time, the internal cavity of the outer sleeve 8 is connected with the groove on the side of the sliding sleeve 11 to form a liquid channel. The pressurization continues, and the movable ball seat 19 shears off the ball seat pin 20 and continues to move downward. The liquid outlet of the blowout preventer inner plug is opened and connected with the liquid channel of the blowout preventer working cylinder 3. At this time, the pipe string operation is carried out, and the liquid in the oil tubing string is diverted to the oil casing annulus through the liquid outlet of the blowout preventer inner plug and the liquid pipeline of the blowout preventer working cylinder 3, and will not flow out of the wellhead from the oil pipe, thereby realizing the sealing function of the liquid in the pipe string at the lower end of the blowout preventer and the tool section.

[0067] When dismantling the wellhead again, the tubing is lifted up to unseal the matching packer 4. At this time, the packer 23 moves upward to drive the rubber sleeve assembly 30 to move upward, thereby restoring the rubber sleeve assembly 30 to its original position and unsealing the packer. Then, the artificial well bottom is explored downward. After the tubing hits the bottom of the well, the sleeve 61 rebounds against the bottom to restore the tool to the state when it entered the well. The multifunctional blowout-preventing tail pipe 6 realizes the function of leakage and blowout prevention at the bottom of the tubing again; the anti-backflow water distributor 5 in the middle tool section prevents the liquid outside the tubing from entering the tubing; the blowout-preventing working tube 3 plays the function of leakage and blowout prevention of the liquid in the tubing above the tool section, realizing blowout prevention during the entire operation process.

[0068] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be determined by the claims.

Claims

1. A process string suitable for water injection wells in Fuyang oil layer, characterized in that: include: A casing (1), an oil pipe (2) is inserted into the casing (1), and a blowout prevention working cylinder (3), a production pipe string and a multifunctional blowout prevention tail pipe (6) are arranged in sequence below the oil pipe (2); The blowout prevention working cylinder (3) is provided with an anti-blowout inner plug, and the anti-blowout inner plug and the blowout prevention working cylinder (3) cooperate to open the oil casing channel; The production tubing string comprises a plurality of matching packers (4) which divide the production tubing string into a plurality of layers, and each layer is provided with an anti-backflow water distributor (5).

2. The process pipe string adapted to the water injection well of the Fuyang oil layer according to claim 1 is characterized in that: The anti-blowout working cylinder (3) comprises a sliding sleeve (11), a sliding sleeve retaining spring seat (10) is arranged above the sliding sleeve (11); the sliding sleeve (11) is installed in the outer sleeve (8) after being connected to the sliding sleeve retaining spring seat (10); a sliding sleeve upper joint (7) is arranged above the sliding sleeve retaining spring seat (10), the sliding sleeve upper joint (7) is threadedly connected to the upper end of the outer sleeve (8), and the lower end is threadedly connected to the sliding sleeve lower joint (13); the sliding sleeve (11) and the outer sleeve (8) are fixed by a fixing pin (12); a sliding sleeve retaining spring (9) is arranged on the outside of the top end of the sliding sleeve (11); a horse tooth buckle is arranged inside the outer sleeve (8), and a outer sleeve liquid outlet hole is arranged at the corresponding part of the groove of the outer sleeve (8) and the sliding sleeve (11).

3. The process pipe string adapted to the Fuyang oil layer water injection well according to claim 1 is characterized in that: The anti-blowout internal plug includes an expansion sleeve (14), the expansion sleeve (14) is connected to an anti-blowout internal plug sealing sleeve (15) at the bottom, the anti-blowout internal plug sealing sleeve (15) is connected to an internal plug connecting sleeve (21) at the bottom, and the internal plug connecting sleeve (21) is connected to a conical head (22) at the bottom; a spring claw is provided at the top of the expansion sleeve (14); the interior of the internal plug connecting sleeve (21) is threadedly connected to the anti-blowout valve assembly (16); a movable ball seat (19) is fixed in the internal plug connecting sleeve (21) by a ball seat pin (20), and an internal plug steel ball (18) is provided above the movable ball seat (19); an internal plug liquid outlet is provided in the portion of the internal plug connecting sleeve (21) corresponding to the bottom of the movable ball seat (19); and a plurality of anti-blowout internal plug sealing rings (17) are provided on the anti-blowout internal plug sealing sleeve (15).

4. The process pipe string adapted to the Fuyang oil layer water injection well according to claim 1 is characterized in that: The matching packer (4) comprises a packer center tube (24), the upper end of the packer center tube (24) is connected to the packer upper joint (23), and the packer upper outer sleeve (25) is arranged outside the packer upper joint (23); the lower end of the packer center tube (24) is connected to the packer lower joint (43), and the packer lower outer sleeve (41) is arranged outside the packer lower joint (43); An upper well-washing piston (26) is provided between the upper outer sleeve (25) of the packer and the center tube (24) of the packer. The upper well-washing piston (26) can move up and down, and the lower end of the upper well-washing piston (26) is connected to the well-washing piston (27); an outer center tube (29) is provided outside the center tube (24) of the packer, and a first center tube side hole and a second center tube side hole are provided at upper and lower ends of the outer center tube (29); The inner side of the lower end of the packer upper outer sleeve (25) is threadedly connected to the upper stop ring (28) of the rubber cylinder, the lower stop ring (31) of the rubber cylinder is connected below the upper stop ring (28), and a rubber cylinder assembly (30) is provided between the upper stop ring (28) of the rubber cylinder and the lower stop ring (31); The lower stop ring (31) of the rubber cylinder is fixed on the retaining spring fixing sleeve (33) through a setting pin (32), and the retaining spring fixing sleeve (33) is threadedly connected to the center tube (24) of the packer; the retaining spring fixing sleeve (33) is fixed on the unsealing sleeve (35) through an unsealing pin (34), and the unsealing sleeve (35) is threadedly connected to the retaining spring fastening sleeve (37), and a groove is provided between the retaining spring fixing sleeve (33) and the retaining spring fastening sleeve (37), and a retaining spring (36) is provided in the groove; A retaining spring hanger (38) is provided below the outer side of the lower stop ring (31) of the rubber cylinder, and a horse tooth buckle is provided inside the retaining spring hanger (38); the lower side of the retaining spring hanger (38) is connected to the lower outer sleeve (41) of the packer; An annular space is provided between the packer center tube (24), the packer lower outer sleeve (41) and the packer lower joint (43), and an upper setting piston (39), a piston transition (40) and a lower setting piston (42) are provided in the annular space; the upper setting piston (39) is mounted on a boss at the lower end of a retaining spring hanger (38); The packer center tube (24) is provided with a first through hole at a position corresponding to between the packer upper outer sleeve (23) and the upper well washing piston (26), the packer center tube (24) is provided with a second through hole at a position corresponding to between the upper setting piston (39) and the piston transition (40), and the packer center tube (24) is provided with a third through hole at a position corresponding to between the lower setting piston (42) and the packer lower joint (43).

5. The process pipe string adapted to the water injection well of Fuyang oil layer according to claim 1 is characterized in that: The anti-backflow water distributor (5) comprises an eccentric body (51), a biased hole is provided in the eccentric body (51), and a plug (49) is provided in the biased hole; a ceramic ball (50) is provided in the water nozzle of the plug (49), and the diameter of the ceramic ball (50) matches the inner diameter of the plug (49) to form a one-way valve structure; The upper part of the eccentric body (51) is connected to the straightening body (48), and the upper part of the water distributor (44) is provided on the upper part of the straightening body (48); the outer part of the straightening body (48) is provided with an upper connecting sleeve (47) of the water distributor, the upper end of the upper connecting sleeve (47) of the water distributor is connected to the upper connecting sleeve (44) of the water distributor, the lower end of the upper connecting sleeve (47) of the water distributor is connected to the eccentric body (51), the lower end of the eccentric body (51) is connected to the lower connecting sleeve (52) of the water distributor, and the lower part of the lower connecting sleeve (52) of the water distributor is connected to the lower connecting sleeve (53) of the water distributor; A lower guide body (54) is arranged in the lower joint (53) of the water distributor, a guide sleeve (45) is arranged between the upper joint (44) of the water distributor and the straightening body (48), and an upper guide body (46) is arranged in the guide sleeve (45).

6. The process pipe string adapted to the water injection well of Fuyang oil layer according to claim 1 is characterized in that: The multifunctional blowout-proof tail pipe (6) comprises a sleeve (61), the upper inner side of the sleeve (61) is threadedly connected to the blowout-proof tail pipe upper sliding sleeve (59) through a connecting piece (60), the upper side of the blowout-proof tail pipe upper sliding sleeve (59) is connected to the blowout-proof tail pipe upper joint (55) through a fixing piece (57), the lower inner side of the sleeve (61) is connected to the blowout-proof tail pipe lower sliding sleeve (63), and a spring (62) is provided between the connecting piece (60) and the blowout-proof tail pipe lower sliding sleeve (63); the fixing piece (57) is provided with a first side hole of the fixing piece, and the bottom of the fixing piece (57) is a spring claw structure; the fixing piece (57) is provided with a baffle plate (56) and a steel ball (58), and the baffle plate (56) is provided with a plurality of liquid holes.

7. The process pipe string adapted to the water injection well of the Fuyang oil layer according to claim 6 is characterized in that: The blowout-proof tail pipe upper sliding sleeve (59) is connected to the inner side of the fixing member (57) and is threadedly connected to the baffle plate; the blowout-proof tail pipe upper sliding sleeve (59) and the fixing member (57) move relative to each other; a limit block is provided on the fixing member (57), and the limit block is used to limit the downward movement of the blowout-proof tail pipe upper sliding sleeve (59); a conical surface is provided on the surface of the blowout-proof tail pipe upper sliding sleeve (59); a steel ball (58) is arranged between the baffle plate (56) and the blowout-proof tail pipe upper sliding sleeve (59); and a second side hole of the fixing member equal to the first side hole of the fixing member on the fixing member (57) is provided on the blowout-proof tail pipe upper sliding sleeve (59); The top and bottom of the sleeve (61) are respectively provided with circular grooves capable of fixing the spring claws of the fixing member (57); the lower end of the lower sleeve (63) of the blowout-proof tail pipe is provided with a liquid inlet hole; and the boss at the bottom end of the outer sleeve (61) limits the downward movement of the lower sleeve (63) of the blowout-proof tail pipe.

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