A compression-type dual independent sealed unit packer

Abstract

The application discloses a compression type double-independent sealing unit packer and relates to the technical field of oil and gas exploitation processes, which solves the technical problem that a conventional packer cannot simultaneously meet the effective sealing of the packer under low-temperature-high-temperature working condition conversion. The packer comprises an upper sealing mechanism, a lower sealing mechanism, a coupling mechanism, an upper locking mechanism, a lower locking mechanism and a releasing mechanism. The upper sealing mechanism comprises an upper sealing unit assembly, an upper sealing unit gasket ring, an upper sealing unit assembly adjusting ring and an upper setting pin, the lower sealing mechanism comprises a lower sealing unit assembly, a lower setting pin and a lower sealing unit gasket ring, the upper setting pin and the lower setting pin are both shear pin structures, and the shear force of the upper setting pin is greater than that of the lower setting pin. Through the sealing, locking, releasing and coupling of the double-independent sealing unit, the problems that the conventional packer cannot simultaneously meet the effective sealing of the packer under low-temperature-high-temperature working condition conversion and cannot simultaneously release under various complex working conditions are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas exploitation, and particularly relates to a compression type double independent sealing unit packer. BACKGROUND

[0002] The packer is a downhole tool used to seal the annulus or isolate the target zone, control the injection or production fluid, and bear the pressure difference, and the sealing mechanism is one of the cores of the design, and the sealing mechanism is used to effectively seal the work string and the casing annulus in different operation / production processes.

[0003] The limitations of the conventional packer are as shown in the following table. Figure 1

[0004] The conventional packer adopts a set of sealing units to meet the sealing needs in a single working condition. Different sealing elements of the packer are replaced in different working conditions to meet the sealing needs. For the gravel packing sand prevention of the heavy oil thermal recovery well, from the construction to the thermal production, two extreme environments are involved: (1) the high-pressure packing working condition in the packing operation stage; and (2) the high-temperature (up to 350 DEG C) working condition in the thermal production. Both working conditions need the packer to realize effective sealing. The packing operation stage needs to bear the pressure of 35 MPa at low temperature, and the thermal production stage needs to bear the pressure (10-15 MPa) at high temperature of 350 DEG C. According to the current research and understanding, there is no high and low temperature independent rubber cylinder in a set of packer to solve the sealing problem in different complex working conditions.

[0005] In the past, the gravel packing sand prevention adopts the packer combination to realize the sealing problem of the packer in the two extreme working conditions, that is, one Y-type high-temperature packer (compression type) + one Z-type packing tool (self-sealing bowl type). Since the Z-type packing tool adopts the bowl sealing, the sealing pressure is low, and in the case of poor scraping pipe or large wellbore inclination, the effective sealing cannot be realized, and the gravel pipe string is stuck. SUMMARY

[0006] The present application provides a compression type double independent sealing unit packer, which solves the technical problem that the conventional packer cannot simultaneously meet the effective sealing of the packer under the low-temperature-high-temperature working condition change.

[0007] ​The application provides a compression type double independent sealing unit packer, which comprises an upper sealing mechanism, a lower sealing mechanism, a coupling mechanism, an upper locking mechanism, a lower locking mechanism and an unsealing mechanism, the upper sealing mechanism comprises an upper sealing unit assembly, an upper sealing unit gasket ring, an upper sealing unit assembly adjusting ring and an upper setting pin, the lower sealing mechanism comprises a lower sealing unit assembly, a lower setting pin and a lower sealing unit gasket ring, the coupling mechanism comprises an intermediate spacer ring assembly, the upper locking mechanism comprises a setting transmission pipe, a lead-in seat, an upper sealing unit locking ring and an upper locking connecting ring, the lower locking mechanism comprises an upper working barrel, a sealing O-shaped ring, a lower working barrel and a lower locking claw spring, and the unsealing mechanism comprises an unsealing pin and an unsealing ring, wherein the upper sealing unit assembly is made of a material suitable for low-temperature working conditions, the lower sealing unit assembly is made of a material suitable for high-temperature working conditions, the upper setting pin and the lower setting pin are both shear pin structures, and the shear force of the upper setting pin is greater than that of the lower setting pin.

[0008] In some embodiments, the upper sealing unit gasket ring is in a circular ring shape, a lower end surface of the upper sealing unit gasket ring is attached to the upper sealing unit assembly, and an upper end surface of the upper sealing unit gasket ring is attached to a lower end surface of the upper sealing unit assembly adjusting ring.

[0009] The upper end of the upper sealing unit assembly adjusting ring is threadedly connected to the upper locking connecting ring, and a side wall of a lower end cylindrical barrel of the upper sealing unit assembly adjusting ring is provided with a plurality of first pin hole uniformly distributed.

[0010] The upper setting pin is a shear pin structure, an upper part of the upper setting pin is a first pin body part in a cylindrical shape, a thread buckle is arranged on an outer wall of the first pin body part, a lower part of the upper setting pin is a first pin head part in a cylindrical shape, the first pin body part is installed and fixed in the first pin hole of the upper sealing unit assembly adjusting ring through thread connection, and the first pin head part is inserted into a first drill counterbore of the upper lead-in seat.

[0011] In some embodiments, the lower sealing unit gasket ring is in a circular tube structure, a side wall of an upper end cylindrical barrel of the lower sealing unit gasket ring is provided with a plurality of second pin holes uniformly distributed.

[0012] The lower setting pin is a shear pin structure, an upper part of the lower setting pin is a second pin body part in a cylindrical shape, a thread buckle is arranged on an outer wall of the second pin body part, a lower part of the lower setting pin is a second pin head part in a cylindrical shape, the second pin body part is installed in the second pin hole of the lower sealing unit gasket ring through thread connection, and the second pin head part is inserted into a second drill counterbore of the upper working barrel.

[0013] In some embodiments, the intermediate spacer ring assembly comprises a half moon ring, a clamp, a lower gasket ring of the upper sealing unit, a coupling pin and a lower sealing unit adjusting ring.

[0014] The half moon ring is two congruent half circular clamps, and the two half circular clamps can form a complete circular ring.

[0015] The clamp is a cylindrical structure, the outer cylindrical surface of the clamp is provided with a thread, the inner cylindrical wall surface of the clamp is provided with a cylindrical groove at the upper end, the half moon ring is gap-fitted in the cylindrical groove, the lower end surface of the cylindrical groove is in abutment with the lower end surface of the half moon ring, and the upper end surface of the clamp is flush with the upper end surface of the half moon ring;

[0016] The upper sealing unit lower ring is a circular tube, the upper end cylindrical side wall of the upper sealing unit lower ring is uniformly provided with a plurality of third pin holes, the lower end inner wall surface of the upper sealing unit lower ring is provided with an internal thread to realize threaded connection and fixation with the clamp, and the upper end surface of the upper sealing unit lower ring is in abutment with the lower end surface of the upper sealing unit assembly;

[0017] The coupling pin is a shear pin structure, the upper part of the coupling pin is a cylindrical third pin body part, the outer wall of the third pin body part is provided with a threaded buckle, the lower part of the coupling pin is a cylindrical third pin head part, the third pin body part is installed and fixed in the third pin hole of the upper sealing unit lower ring through threaded connection, and the third pin head part is inserted into the third matching drill counterbore of the upper working barrel;

[0018] The lower sealing unit adjusting ring is a circular tube, the upper end inner wall surface of the lower sealing unit adjusting ring is provided with an internal thread to realize threaded connection and fixation with the clamp, and the lower end surface of the lower sealing unit adjusting ring is in abutment with the upper end surface of the lower sealing unit assembly;

[0019] The upper working barrel is a circular tube, the part of the upper working barrel matched with the intermediate spacer ring assembly is provided with a first annular groove, the axial dimension of the first annular groove is equal to the sum of the axial dimension of the half moon ring and the setting compression distance of the upper sealing unit assembly, the upper end surface of the half moon ring is in abutment with the upper boss surface of the first annular groove, the half moon ring is clamped in the first annular groove, and the clamp can completely cover the first annular groove, so that the lower end surface of the clamp does not scratch the lower boss surface of the annular groove.

[0020] In some embodiments, the setting transmission pipe is a circular tube, the upper end cylinder of the setting transmission pipe is gap-fitted on the outer side surface of the lead-in seat, and the lower end cylinder of the setting transmission pipe is fixedly connected with the upper locking connection ring through a thread;

[0021] The lead-in seat is a circular tube, the outer cylindrical wall surface of the middle cylinder of the lead-in seat is provided with a first reverse tooth type thread buckle, the lower end cylinder of the lead-in seat is threadedly connected with the upper working barrel, and the lower end inner surface of the lead-in seat is flush with the upper end inner surface of the upper working barrel;

[0022] The upper sealing unit lock ring is an open circular ring structure, and the inner wall surface of the upper sealing unit lock ring is provided with a second reverse tooth type thread buckle, and the second reverse tooth type thread buckle and the first reverse tooth type thread buckle are a set of matched thread pairs, which can effectively engage with each other, and under the influence of the reverse tooth structure, under the parallel to the axis thrust, the upper sealing unit lock ring can only move from the upper end to the lower end of the lead-in seat, and cannot move from the lower end to the upper end of the lead-in seat.

[0023] After the setting transmission force pipe and the upper locking connection ring are connected and fixed, a second annular groove is formed on the inner side surface, and the upper sealing unit lock ring gap is arranged in the second annular groove.

[0024] In some embodiments, the upper working barrel is a circular tube, and the lower end cylinder of the upper working barrel is connected to the lower locking claw spring through threads, and the outer circle of the lower end cylinder of the upper working barrel is inserted into the lower working barrel, and the cooperation of the upper working barrel and the lower working barrel is sealed by the sealing O-ring.

[0025] The lower working barrel is a circular tube, and the upper end of the lower working barrel is connected to the lower sealing unit pad ring through threads, and the third annular groove is formed between the lower working barrel and the lower sealing unit pad ring, and the upper working barrel is inserted into the third annular groove, and the inner wall of the lower end cylinder of the lower working barrel is provided with a third reverse tooth type thread buckle, and the inner circle of the lowermost end cylinder of the lower working barrel is flush with the inner circle of the upper end cylinder of the upper working barrel.

[0026] The lower locking claw spring is a circular tube structure, which includes an upper pawl part, a middle connecting part and a lower pawl part from top to bottom.

[0027] The outer circle of the upper pawl part is provided with a thread buckle to connect with the upper working barrel, and the side wall of the cylinder body of the upper pawl part is provided with a through hole groove, and the thread buckle of the upper pawl part is in a split state and uniformly distributed in the circumference, and the inner circle of the upper pawl part is flush with the inner circle of the lower end surface of the upper working barrel.

[0028] The middle connecting part is connected to the upper pawl part at the upper end, and is connected to the lower pawl part at the lower end.

[0029] The lower pawl part is provided with a fourth reverse tooth type thread buckle on the outer circle, and the side wall of the cylinder body of the lower pawl part is provided with a through hole groove, and the fourth reverse tooth type thread buckle is in a split state and uniformly distributed in the circumference.

[0030] The fourth reverse tooth type thread buckle and the third reverse tooth type thread buckle are a set of matched thread pairs, which can effectively engage with each other, and under the influence of the reverse tooth structure, under the parallel to the axis thrust, the lower locking claw spring can only move from the upper end to the lower end of the lower working barrel, and cannot move from the lower end to the upper end of the lower working barrel.

[0031] The upper pawl part exerts pulling force on the upper working cylinder and the lower locking pawl spring without radial support, the threaded connection of the upper working cylinder and the lower locking pawl spring is translated relative to each other due to the radial contraction of the upper pawl part, and finally the threaded connection is disconnected.

[0032] In some embodiments, the unsealing ring is in a circular tube shape, and the unsealing ring is sleeved on the inner side of the upper working cylinder unsealing cylinder and the inner side of the upper pawl part of the lower locking pawl spring in a clearance fit manner.

[0033] The unsealing pin is in a shear pin structure, the upper part of the unsealing pin is a fourth pin body part in a cylindrical shape, a threaded buckle is arranged on the outer wall of the fourth pin body part, the lower part of the unsealing pin is a fourth pin head part in a cylindrical shape, the fourth pin body part is installed in the fourth pin hole of the upper working cylinder in a threaded connection manner, and the fourth pin head part is inserted into the fourth counterbore of the unsealing ring.

[0034] In some embodiments, the shear force of the upper setting pin is 1.2-1.5 times that of the lower setting pin.

[0035] In some embodiments, the upper end of the introduction seat is provided with a tapered chamfer to facilitate guiding other downhole operation tools into the inside of the packer.

[0036] In some embodiments, the outer circle of the middle connecting part of the lower locking pawl spring is lower than the root circle of the fourth reverse tooth type threaded buckle of the lower locking pawl spring, so that the lower locking pawl spring can move smoothly.

[0037] The application has the following beneficial effects: a compression type double independent sealing unit packer is provided, the sealing, locking, unsealing and coupling mechanisms of the double independent sealing unit are used, the effective sealing of the packer under the low-temperature-high-temperature working condition change that cannot be met by the conventional packer is solved, the complexity and disadvantages of the original gravel packing sand prevention Y115 type high-temperature packer+Z331 type packing tool are effectively replaced by one set of compression type double independent sealing unit packer, the gravel packing sand prevention construction success rate and sand prevention effect are further improved through 35MPa packing pressure improvement and compression type rubber cylinder instead of self-sealing skin bowl, and the unsealing problem of the conventional packer under various complex working conditions is solved by designing the unsealing reserved area of the upper sealing unit in the spacer ring assembly. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application.

[0039] Figure 1 FIG. 1 is a structural schematic diagram of a conventional packer single sealing unit;

[0040] Figure 2Structure diagram of a conventional packer non-independent high and low temperature unit;

[0041] Figure 3 Structure diagram of a conventional packer non-independent high and low temperature unit; Figure 2 Structure diagram of a conventional packer non-independent high and low temperature unit;

[0042] Figure 4 Structure diagram of a conventional packer non-independent high and low temperature unit; Structure diagram of a conventional packer non-independent high and low temperature unit;

[0043] Structure diagram of a conventional packer non-independent high and low temperature unit; Figure 5 Structure diagram of a conventional packer non-independent high and low temperature unit; Figure 4 Structure diagram of a conventional packer non-independent high and low temperature unit; Structure diagram of a conventional packer non-independent high and low temperature unit;

[0044] Structure diagram of a conventional packer non-independent high and low temperature unit; Figure 6 Structure diagram of a conventional packer non-independent high and low temperature unit; Structure diagram of a conventional packer non-independent high and low temperature unit;

[0045] Structure diagram of a conventional packer non-independent high and low temperature unit; Figure 7 Structure diagram of a conventional packer non-independent high and low temperature unit; Figure 6 Structure diagram of a conventional packer non-independent high and low temperature unit; Structure diagram of a conventional packer non-independent high and low temperature unit;

[0046] Structure diagram of a conventional packer non-independent high and low temperature unit; Figure 8 Structure diagram of a conventional packer non-independent high and low temperature unit; Structure diagram of a conventional packer non-independent high and low temperature unit;

[0047] Structure diagram of a conventional packer non-independent high and low temperature unit; Figure 9 Structure diagram of a conventional packer non-independent high and low temperature unit; Structure diagram of a conventional packer non-independent high and low temperature unit;

[0048] Structure diagram of a conventional packer non-independent high and low temperature unit; Figure 10 Structure diagram of a conventional packer non-independent high and low temperature unit. Structure diagram of a conventional packer non-independent high and low temperature unit.

[0049] DETAILED DESCRIPTION DETAILED DESCRIPTION DETAILED DESCRIPTION

[0050] The embodiment discloses a compression type double independent sealing unit packer, and solves the technical problem that a conventional packer cannot simultaneously meet the effective sealing of the packer under low temperature-high temperature working condition conversion.

[0051] Aiming at a set of packer using high and low temperature independent rubber cylinder to solve the sealing problem of different complex working conditions, first of all, it is not feasible to replace the sealing unit of the conventional packer with two different working condition sealing units, as follows.

[0052] As shown in Figure 2 , the single sealing unit of the conventional packer is replaced by two low temperature and high temperature sealing units, and a set of locking mechanism is used to lock the high and low temperature "rubber cylinder" at the same time, so the pressure stress between the two rubber cylinders is related to each other, not independent double rubber cylinder. First of all, because a set of locking mechanism is used, only free spacer ring can be used between the two sealing units; and because the free spacer ring is directly used between the two sealing units, the free spacer ring bears the pressure of the upper and lower sealing units, the two forces are equal and interact with each other, and when one force does not exist, the other force will also disappear, as shown in Figure 3 .

[0053] Take gravel packing as an example: although the low temperature rubber cylinder can withstand 35MPa sealing pressure during gravel packing sand prevention, but in the later stage of 350℃ high temperature thermal recovery, the low temperature rubber cylinder (hydrogenated nitrile rubber) will be carbonized due to high temperature, at this time the axial pressure stress of high temperature "rubber cylinder" will completely disappear, resulting in a significant reduction of high temperature "rubber cylinder" sealing pressure, and further causing the sealing failure of the packer.

[0054] Thirdly, if the conventional packer is improved to two independent rubber cylinders, there will be a problem of unsealing, as follows.

[0055] As shown in Figure 4 , the free spacer ring is replaced by a fixed spacer ring, realizing the fixed spacer ring and the outer center tube as a whole; a set of "lower locking assembly" is replaced by one set of "locking assembly" for each of the upper and lower. The lower sealing unit (sealing unit 2) adopts high temperature resistant composite material, which is used for high temperature thermal recovery pressure requirement, and is sealed and locked by "lower locking assembly". The upper sealing unit (sealing unit 1) adopts hydrogenated nitrile rubber material, which can meet the sealing pressure requirement of 35MPa at low temperature, and is sealed and locked by "upper locking assembly".

[0056] As shown in Figure 5 , the original free spacer ring is subjected to a group of forces, and the fixed spacer ring becomes two groups of forces. The two sealing units are independent of each other. When the packer changes from one working condition to another, such as from low temperature to high temperature, the low temperature sealing of the packer fails, which will not affect the sealing of the high temperature.

[0057] However, this structure design has a problem, that is, the problem of unsealing. When the packer is unsealed, two sets of locking mechanisms need to be unlocked respectively, otherwise effective unsealing cannot be achieved, resulting in packer sticking accidents. In this case, only when both sets of unlocking mechanisms are unlocked can it be known that the packer is effectively unlocked. When the first set of packer unlocking mechanism is unlocked, it is difficult to determine whether the downhole tool is effectively unlocked on the ground. Therefore, the packer structure is usually designed with only one unlocking structure.

[0058] Embodiment 1

[0059] In order to solve the problem that the conventional packer adopts a single sealing unit and cannot meet the sealing needs of various complex working conditions, the embodiment discloses a compression type double independent sealing unit packer, which relates to a sealing, locking, unsealing and coupling mechanism of double independent sealing units. The mechanism has the advantages of reliable sealing under low temperature and high temperature conditions respectively, and has the advantages of easy unsealing and recovery.

[0060] The compression type double independent sealing unit packer relates to a sealing, locking, unsealing and coupling mechanism of double independent sealing units, which comprises an upper sealing mechanism, a lower sealing mechanism, a coupling mechanism, an upper locking mechanism, a lower locking mechanism and an unsealing mechanism.

[0061] Please refer to Figure 6 The upper sealing mechanism comprises an upper sealing unit assembly 7, an upper sealing unit gasket ring 6, an upper sealing unit assembly adjusting ring 5 and an upper setting pin 17. The upper sealing mechanism is closely related to the coupling mechanism, and the upper sealing mechanism is closely related to the upper locking mechanism. The lower sealing mechanism comprises a lower sealing unit assembly 9, a lower setting pin 18 and a lower sealing unit gasket ring 10. The lower sealing mechanism is closely related to the coupling mechanism assembly, and the lower sealing mechanism is closely related to the lower locking mechanism assembly. The coupling mechanism comprises a middle spacer ring assembly 8, and the coupling mechanism is closely related to an upper working barrel 11. The upper locking mechanism comprises a setting transmission pipe 1, an introduction seat 2, an upper sealing unit locking ring 3 and an upper locking connecting ring 4. The lower locking mechanism comprises the upper working barrel 11, a sealing O-ring 12, a lower working barrel 16 and a lower locking claw spring 15, and the lower locking mechanism is closely related to the unsealing mechanism. The unsealing mechanism comprises an unsealing pin 13 and an unsealing ring 14.

[0062] It should be noted that "upper" and "lower" in the embodiment are according to Figure 6 the orientation, that is, described according to the actual use state of the device in the well.

[0063] Regarding the upper sealing mechanism, as Figure 6As shown in the figure, the upper sealing unit assembly 7 is made of a material suitable for low-temperature working conditions. The upper sealing unit gasket ring 6 is circular, the lower end surface of the upper sealing unit gasket ring 6 is attached to the upper sealing unit assembly 7, and the upper end surface of the upper sealing unit gasket ring 6 is attached to the lower end surface of the upper sealing unit assembly adjusting ring 5. The upper end of the upper sealing unit assembly adjusting ring 5 is connected to the upper locking connection ring 4 by threads, and by adjusting the number of threads, the assembly gap between the upper and lower contact surfaces of the upper sealing unit can be eliminated. The lower end of the upper sealing unit assembly adjusting ring 5 is provided with a plurality of first pin holes uniformly distributed on the side wall of the cylindrical barrel.

[0064] Please refer to Figures 6 to 10 The upper setting pin 17 is a shear pin structure, the upper part is a cylindrical first pin body part, the outer wall of the first pin body part is provided with a threaded buckle, and the lower part is a cylindrical first pin head part. Regarding the upper setting pin 17, the first pin body part is installed and fixed in the first pin hole of the upper sealing unit assembly adjusting ring 5 by threads, and the first pin head part is inserted into the first matching drill counterbore of the upper lead-in seat 2.

[0065] Regarding the lower sealing mechanism, please refer to Figure 6 , the lower sealing unit assembly 9 is made of a material suitable for high-temperature working conditions. The lower sealing unit gasket ring 10 is a circular tube structure, and the side wall of the upper end cylindrical barrel of the lower sealing unit gasket ring 10 is provided with a plurality of second pin holes uniformly distributed.

[0066] Please refer to Figures 6 to 10 , the lower setting pin 18 is a shear pin structure, the upper part is a cylindrical second pin body part, the outer wall of the second pin body part is provided with a threaded buckle, and the lower part is a cylindrical second pin head part. Regarding the lower setting pin 18, the second pin body part is installed in the second pin hole of the lower sealing unit gasket ring 10 by threads, and the second pin head part is inserted into the second matching drill counterbore of the upper working barrel 11.

[0067] Regarding the coupling mechanism, the intermediate spacer ring assembly 8 is composed of a half moon ring 81, a clamp 82, a lower gasket ring 83 of the upper sealing unit, a coupling pin 84, and a lower sealing unit adjusting ring 85, and the detailed structure will be explained in combination with the upper working barrel 11.

[0068] Please refer to Figure 6 and Figure 7 , wherein the half moon ring 81 is two congruent semicircular clamps, and please refer to Figure 8 , the two semicircular clamps can form a complete ring. The clamp 82 is a cylindrical structure, the outer circular surface is provided with threads, and the inner circular wall surface is provided with a cylindrical recess, the half moon ring 81 is fitted into the cylindrical recess, the lower end surface of the cylindrical recess is attached to the lower end surface of the half moon ring 81, and the upper end surface of the clamp 82 is flush with the upper end surface of the half moon ring 81.

[0069] The lower gasket 83 of the upper sealing unit is cylindrical. The upper cylindrical side wall of the lower gasket 83 of the upper sealing unit is evenly provided with several third pin holes (i.e. threaded holes). The inner wall of the lower cylindrical side wall of the lower gasket 83 of the upper sealing unit is provided with internal threads, which are used to achieve threaded connection and fixation with the clamp 82. The upper end face of the lower gasket 83 of the upper sealing unit is in contact with the lower end face of the upper sealing unit assembly 7.

[0070] Please refer to the reference. Figures 6 to 10 The coupling pin 84 is a shear pin structure—its upper part is a cylindrical third pin body with threaded threads on its outer wall, and its lower part is a cylindrical third pin head. The coupling pin 84, with its third pin body connected and fixed in the third pin hole of the lower washer ring 83 of the upper sealing unit via a threaded connection, has its third pin head inserted into the third countersunk hole of the upper working cylinder 11.

[0071] The lower sealing unit adjusting ring 85 is cylindrical, and the inner wall of the upper cylindrical part of the lower sealing unit adjusting ring 85 is provided with internal threads, which are threadedly connected and fixed with the clamp 82; the lower end face of the lower sealing unit adjusting ring 85 is in contact with the upper end face of the lower sealing unit assembly 9. By adjusting the number of turns of the threaded connection between the lower sealing unit adjusting ring 85 and the clamp 82, the assembly gap between the upper and lower contact surfaces of the lower sealing unit can be eliminated.

[0072] Regarding the upper working cylinder 11, please refer to the following: Figure 6 and Figure 7 The upper working cylinder 11 is cylindrical, and a first annular groove is provided at the part that mates with the intermediate spacer ring assembly 8. The axial dimension of the first annular groove is equal to "the axial dimension of the crescent ring 81 + the setting compression distance of the upper sealing unit assembly 7". This concept will be combined with... Figure 10 The specific operation process is explained below. The upper end face of the crescent ring 81 is in contact with the upper boss surface of the first annular groove; the crescent ring 81 is engaged within the first annular groove. The clamp 82 can completely cover the first annular groove, including limiting the axial dimension of the clamp 82 to be greater than the axial dimension of the first annular groove, so as to ensure that the lower end face of the clamp 82 does not scrape against the lower boss surface of the annular groove.

[0073] For information on the upper locking mechanism, please refer to [link / reference]. Figure 6 It includes a setting force transmission tube 1, an inlet seat 2, an upper sealing unit locking ring 3, and an upper locking connecting ring 4. The setting force transmission tube 1 is cylindrical, and the upper cylindrical end of the setting force transmission tube 1 is fitted onto the outer side of the inlet seat 2 with a clearance fit; the lower cylindrical end of the setting force transmission tube 1 is threadedly connected and fixed to the upper locking connecting ring 4.

[0074] The upper end of the introduction seat 2 is provided with a tapered chamfer, which can conveniently guide other downhole operation tools into the packer; the outer cylindrical wall surface of the middle cylinder of the introduction seat 2 is provided with a first reverse tooth type thread buckle; the lower end cylinder of the introduction seat 2 is threadedly connected with the upper working cylinder 11, and the lower end inner surface of the introduction seat 2 and the upper end inner surface of the upper working cylinder 11 are flush after connection, which means that the inner surface radii are the same to achieve smooth transition. The upper sealing unit lock ring 3 is an open ring structure, and the inner wall surface thereof is provided with a second reverse tooth type thread buckle. The second reverse tooth type thread buckle of the upper sealing unit lock ring 3 and the first reverse tooth type thread buckle of the introduction seat 2 are a set of thread pairs matched with each other, which can effectively engage with each other. Under the action of the parallel thrust, the upper sealing unit lock ring 3 can only move from the upper end to the lower end of the introduction seat 2, but cannot move from the lower end to the upper end of the introduction seat 2, that is, the movement is unidirectional.

[0075] After the setting transmission force pipe 1 is connected and fixed with the upper locking connection ring 4, a second annular groove is formed on the inner side surface, and the upper sealing unit lock ring 3 is gap-set in the second annular groove. The size of the second annular groove cannot be too large, which can ensure that the upper sealing unit lock ring 3 can smoothly move.

[0076] For the lower locking mechanism, please refer to Figure 6 , which involves that the upper working cylinder 11 is a circular tube, and the lower end cylinder of the upper working cylinder 11 is threadedly connected with the lower locking claw spring 15; the outer cylinder of the lower end cylinder of the upper working cylinder 11 is inserted with the lower working cylinder 16, and the sealing O-ring 12 is used to seal the two matched working surfaces.

[0077] The lower working cylinder 16 is a circular tube, the upper end of the lower working cylinder 16 is threadedly connected with the lower sealing unit pad ring 10, and the third annular groove is formed between the two, and the upper working cylinder 11 is inserted in the third annular groove; the inner wall of the lower end cylinder of the lower working cylinder 16 is provided with a third reverse tooth type thread buckle, and the inner circle of the lowermost end cylinder of the lower working cylinder 16 is flush with the upper end cylinder of the upper working cylinder 11. As to the "flush" here, it can also be explained in detail as follows: Figure 6 In the above, the lower working cylinder 16 is divided into upper end, lower end and lowermost end in order according to the radius from large to small, and the upper working cylinder 11 is divided into upper end and lower end according to the radius from small to large, the lowermost end of the lower working cylinder 16 is the main part thereof, and the upper end of the upper working cylinder 11 is the main part thereof, and the inner diameters of the two main parts are limited to be equal to achieve the flush effect.

[0078] The lower locking claw spring 15 is a circular tube structure, as shown in Figure 6As shown, from top to bottom, the upper pawl part, the middle connecting part and the lower pawl part; the outer circle of the upper pawl part is provided with a threaded buckle to connect with the upper working barrel 11, the side wall of the barrel body is provided with a through hole slot, the threaded buckle is in the form of split, and is uniformly distributed in the circumference; the upper end surface of the upper pawl part is in contact with the lower end surface of the upper working barrel unsealing barrel, and the inner circle of the upper pawl part is flush with the inner circle of the upper working barrel unsealing barrel; the upper end of the middle connecting part is connected with the upper pawl part, and the lower end of the middle connecting part is connected with the lower pawl part; the outer circle of the lower pawl part is provided with a fourth reverse tooth type threaded buckle, the side wall of the barrel body is provided with a through hole slot, and the fourth reverse tooth type threaded buckle is in the form of split and is uniformly distributed in the circumference.

[0079] The fourth reverse tooth type threaded buckle of the lower locking pawl spring 15 and the third reverse tooth type threaded buckle of the lower working barrel 16 are a set of matched threaded pairs, which can effectively engage with each other; after the engagement, under the action of the thrust parallel to the axis, the lower locking pawl spring 15 can only move from the upper end to the lower end of the lower working barrel 16, but cannot move from the lower end to the upper end of the lower working barrel 16, that is, the movement is one-way. The outer circle of the middle connecting part of the lower locking pawl spring 15 is lower than the root circle of the fourth reverse tooth type threaded buckle of the lower locking pawl spring 15, which ensures that the lower locking pawl spring 15 can move smoothly.

[0080] The upper pawl part of the lower locking pawl spring 15 exerts a pulling force on the upper working barrel 11 and the lower locking pawl spring 15 respectively without radial support, and the threaded connection between the two will be translated due to the radial contraction of the upper pawl part of the lower locking pawl spring 15, and finally disconnected, that is, the lower locking fails.

[0081] For the unsealing mechanism, please refer to Figure 6 , and for the unsealing mechanism, please refer to Figure 10 , which involves that the unsealing ring 14 is in the form of a circular tube and is set on the inside of the upper working barrel unsealing barrel and the inside of the upper pawl part of the lower locking pawl spring 18 in a clearance fit manner. The unsealing pin 13 is in the form of a shear pin structure - the upper part is a fourth pin body part in the form of a circular cylinder, the outer wall of the fourth pin body part is provided with a threaded buckle, and the lower part is a fourth pin head part in the form of a circular cylinder; for the unsealing pin 13, the fourth pin body part is installed in the fourth pin hole of the upper working barrel 11 through threaded connection, and the fourth pin head part is inserted into the fourth counterbore hole of the unsealing ring 14.

[0082] Especially, the shear force of the upper setting sealing pin is greater than that of the lower setting sealing pin. Through research and limitation, the shear force of the upper setting sealing pin is 1.2-1.5 times that of the lower setting sealing pin, which is the preferred embodiment.

[0083] The above, the compression type double independent sealing unit packer disclosed in the embodiment, constitutes an interaction method for realizing the downhole setting, coupling sealing and unsealing of the compression type double independent sealing unit packer, which will be explained in detail below in combination with Figures 8 to 10 the process schematic diagram.

[0084] The downhole setting method of the compression type double independent sealing unit packer is as follows:

[0085] In combination with the graphic annotations in Figure 6 , please refer to Figure 8 , the setting load is applied to the setting force transmission pipe 1, and the setting load is transmitted in sequence through the upper locking connecting ring 4, the upper sealing unit assembly adjusting ring 5, the upper setting pin 17, the lead-in seat 2 and the upper working barrel 11, and is further transmitted to the intermediate spacer ring assembly 8 by the upper working barrel 11, and is further transmitted to the lower setting pin 18 by the upper working barrel 11. The lower working barrel 16 is shown as a rack. The lower setting pin 18 is first sheared under the mutual shearing action of the setting load and the reaction force of the lower working barrel 16; the setting load is transmitted to the intermediate spacer ring assembly 8 through the upper working barrel 11, and is transmitted to the lower sealing unit assembly 9 through the intermediate spacer ring assembly 8. The lower sealing unit assembly 9 is expanded under the extrusion action of the setting load and the reaction force of the lower working barrel 16; at the same time, the upper working barrel 11 pushes the lower locking claw spring 15 downward, the lower locking claw spring 15 climbs the teeth of the lower working barrel 16 to lock, until the lower sealing unit 9 is tightly attached to the inner wall of the casing and a seal is formed, and the setting and locking of the lower sealing unit assembly 9 are completed.

[0086] In combination with the graphic annotations in Figure 6 , please refer to Figure 9 , continue to increase the setting load, the extrusion force on the lower sealing unit assembly 9 increases, the internal stress increases, when the setting load increases to a certain extent, the upper setting pin 17 is sheared under the mutual shearing action of the setting load and the reaction force of the lead-in seat 2; at this time, the setting load is transmitted to the upper sealing unit gasket ring 6 through the upper sealing unit assembly adjusting ring 5; the upper sealing unit assembly 7 is expanded under the extrusion action of the setting load and the reaction force of the intermediate spacer ring assembly 8; at the same time, the setting force transmission pipe 1 pushes the upper sealing unit locking ring 3 downward, the upper sealing unit locking ring 3 climbs the teeth of the lead-in seat 2 to lock, until the upper sealing unit is tightly attached to the inner wall of the casing and a seal is formed, and the setting and locking of the upper sealing unit 8 are completed.

[0087] Further illustrate, the compression type double independent sealing unit packer disclosed in the embodiment is in the aspect of realizing the coupling sealing of the packer double independent rubber coupling downhole, and specifically, after the upper and lower sealing unit assemblies are sequentially set and seated under the action of the coupling mechanism, the coupling mechanism does not have mechanism action, but the setting and seating force borne by the upper sealing unit assembly 7 is transmitted to the lower sealing unit assembly 9 through the intermediate spacer ring assembly 8, so that the compression type double independent sealing unit packer can simultaneously meet the sealing needs in low-temperature working conditions. When the compression type double independent sealing unit packer enters high-temperature working conditions, after the upper sealing unit assembly 7 fails to seal, under the support of the intermediate spacer ring assembly 8, the coupling mechanism bears the stress reaction of the lower sealing unit assembly 9, so that the internal stress of the upper sealing unit assembly 7 does not change greatly, thereby ensuring the high-temperature sealing of the compression type double independent sealing unit packer.

[0088] As to the downhole unsealing implementation method of the compression type double independent sealing unit packer, the details are as follows:

[0089] In combination with the graphic annotations in Figure 6 , please refer to Figure 10 The fishing tool is lowered down to act on the unsealing ring 14 to exert an upward unsealing load, the unsealing pin 13 is sheared under the mutual shearing action of the unsealing load and the reaction force of the lower locking mechanism, the unsealing ring 14 moves upward and is attached to the upper convex boss surface of the upper working barrel unsealing barrel to transmit the unsealing load to the upper working barrel 11, at the same time, the upper pawl part of the lower locking claw spring 15 loses the radial support action of the unsealing ring 14, under the action of the unsealing load, the sheared pin 84 (shown in Figure 7 ) of the coupling mechanism is sheared, the upper working barrel 11 translates upward, and the upper sealing unit assembly 7 realizes unsealing; when the intermediate spacer ring assembly 8 translates downward to the lower limit point, the upper working barrel drives the intermediate spacer ring assembly 8 to synchronously translate upward, and the lower sealing unit assembly 9 realizes unsealing.

[0090] In summary, the compression type double independent sealing unit packer provided in the embodiment has at least the following beneficial effects:

[0091] (1) The compression type double independent sealing unit packer solves the problem that the conventional packer cannot simultaneously meet the effective sealing of the packer under the low-temperature-high-temperature working condition change through the sealing, locking, unsealing and coupling mechanism of the double independent sealing unit.

[0092] (2) The compression type double independent sealing unit packer effectively replaces the complexity and disadvantages of the original gravel packing sand prevention Y115 type high-temperature packer + Z331 type filling tool through 35MPa filling pressure improvement and compression type rubber instead of self-sealing bowl, which can further improve the construction success rate and sand prevention effect of gravel packing sand prevention.

[0093] (3) The invented compression type double independent sealing unit packer, wherein the intermediate spacer ring assembly is designed with a reserved area for unsealing of the upper sealing unit, solving the problem that the conventional packer cannot be unsealed simultaneously under various complex working conditions.

[0094] Example 2

[0095] Based on Example 1, the process shown in Figure 8 , Figure 9 and Figure 10 is further described as follows.

[0096] The process of the mechanism to achieve setting in the well is shown in Figures 8-9 .

[0097] Step 1: Lower sealing unit setting, lower locking mechanism synchronous locking. When the liquid cylinder pushes the transmission pipe 1, it pushes the upper sealing unit lock ring 3 to be in threaded contact with the upper locking connection ring 4, and pushes the upper working barrel 11 to set down, as the maximum shear stress borne by the lower setting pin 18 is smaller than that of the upper setting pin 17, the lower setting pin 18 is cut off first, the lower sealing unit assembly 9 is set down, and the stress is transmitted to the lower locking claw spring 15, which is provided with a sawtooth buckle to engage with the cylinder to keep it from moving, fixing the upper working barrel 11 and the lower working barrel 16 to prevent them from moving relative to each other, ensuring that the lower sealing unit can be locked and fixed.

[0098] Step 2: Upper sealing unit setting, upper locking mechanism synchronous locking. After the lower sealing unit assembly 9 is set down, the lower sealing unit assembly 9 generates swelling stress to press the intermediate spacer ring assembly 8, and the coupling pin 84 in the intermediate spacer ring assembly 8 is designed with a step with the upper working barrel 11 to ensure that the stress transmitted to the intermediate spacer ring assembly 8 always exists, which generates coupling effect to ensure that the two sealing assemblies are subjected to two independent forces, and the sealing is not affected. When the pushing force of the liquid cylinder reaches the maximum shear stress of the upper setting pin 17, the upper setting pin 17 is cut off, and the upper sealing unit assembly 8 is set down. After the upper sealing unit assembly 8 is set down, the force of the liquid cylinder acting on the setting transmission pipe 1 is removed, and the force on the upper locking connection ring 4 is bounced to the upper sealing unit lock ring 3 due to the setting of the rebound device on the upper locking connection ring 4. At this time, the upper sealing unit lock ring 3 is tightly engaged with the lead-in seat 2 through the sawtooth buckle, so there is a continuous force on the lead-in seat 2 and acting on the upper sealing unit assembly 7 through the upper sealing unit pad ring 6, and at this time, the intermediate spacer ring assembly 8 always has a force as described above, which ensures that the upper sealing unit assembly 7 always bears forces in both directions, and is independently sealed.

[0099] The process of the mechanism to achieve unsealing in the well is shown in Figure 10 .

[0100] The fishing spear is lowered to the unblocking ring 14, causing the unblocking ring 14 to be pulled up to the inner ledge of the upper working barrel 11, and the upper working barrel 11 is pushed to move forward, when the stress of moving forward reaches the maximum shear stress of the coupling pin 84 in the intermediate spacer ring assembly 8, the coupling pin 84 is sheared, and the upper sealing unit assembly 7 is unblocked. At this time, although the expansion stress of the upper sealing unit assembly 7 to the intermediate assembly spacer ring 8 disappears, because the lower sealing unit assembly 9 has transmitted the expansion stress to the step in the intermediate spacer ring assembly 8 when it is set, the stress on the step always exists, and the coupling effect is generated, so even if the upper sealing unit assembly 7 has completed unblocking, the lower sealing unit assembly 9 is not affected. When the upper working barrel 11 drives the intermediate spacer ring assembly 8 to continue to move forward, when the displacement is the movable space (the unblocking reserved area of the upper sealing unit, as shown in the middle schematic) in the intermediate spacer ring assembly 8, the lower sealing unit assembly 9 is unblocked. Figure 7

[0101] In the embodiments of the present application, the first, second, third, etc. are described in many places, which are only used for mutual distinction, and do not represent the importance and other meanings, such as the first pin hole, the second pin hole, the third pin hole and the fourth pin hole, which are distinguished to make the description more perfect.

[0102] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all the preferred embodiments and all the changes and modifications falling within the scope of the present application.

[0103] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.​

Claims

1. A compression-type double independent sealing unit packer, characterized in that, include: The upper sealing mechanism includes an upper sealing unit assembly, an upper sealing unit gasket ring, an upper sealing unit assembly adjusting ring, and an upper setting pin; The lower sealing mechanism includes a lower sealing unit assembly, a lower setting pin, and a lower sealing unit gasket ring; The coupling mechanism includes an intermediate spacer ring assembly; The upper locking mechanism includes a setting force transmission tube, an inlet seat, an upper sealing unit locking ring, and an upper locking connecting ring; The lower locking mechanism includes an upper working cylinder, a sealing O-ring, a lower working cylinder, and a lower locking claw spring; Unsealing mechanism, including unsealing pin and unsealing ring; The upper sealing unit assembly is made of a material suitable for low-temperature conditions, and the lower sealing unit assembly is made of a material suitable for high-temperature conditions. Both the upper and lower setting pins are shear pin structures, and the shearing force of the upper setting pin is greater than that of the lower setting pin. The intermediate spacer ring assembly includes a crescent ring, a clamp, a lower gasket ring of the upper sealing unit, a coupling pin, and an adjusting ring of the lower sealing unit. The crescent ring consists of two congruent semi-circular clamps. The clamp has a cylindrical structure with a cylindrical groove at the upper end of its inner circular wall. The crescent ring is fitted into the cylindrical groove with a clearance fit. The lower cylindrical inner wall of the lower gasket ring of the upper sealing unit is connected and fixed to the clamp. The upper cylindrical inner wall of the adjusting ring of the lower sealing unit is connected and fixed to the clamp. The upper working cylinder is cylindrical, and a first annular groove is provided at the part of the upper working cylinder that mates with the intermediate spacer assembly. The axial dimension of the first annular groove is equal to the sum of the axial dimension of the crescent ring and the setting compression distance of the upper sealing unit assembly. The upper end face of the crescent ring is in contact with the upper boss surface of the first annular groove, and the crescent ring is engaged in the first annular groove.

2. The compression-type dual independent sealing unit packer as described in claim 1, characterized in that, The upper sealing unit gasket is circular, and the lower end face of the upper sealing unit gasket is in contact with the upper sealing unit assembly. The upper end face of the upper sealing unit gasket is in contact with the lower end face of the upper sealing unit assembly adjustment ring. The upper end of the upper sealing unit assembly adjustment ring is threadedly connected to the upper locking connection ring, and the lower end of the cylindrical side wall of the upper sealing unit assembly adjustment ring is provided with several evenly distributed first pin holes. The upper setting pin is a shear pin structure. The upper part of the upper setting pin is a cylindrical first pin body with a threaded thread on the outer wall of the first pin body. The lower part of the upper setting pin is a cylindrical first pin head. The first pin body is installed and fixed in the first pin hole of the upper sealing unit assembly adjustment ring by threaded connection. The first pin head is inserted into the first countersunk hole of the upper guide seat.

3. The compression-type dual independent sealing unit packer as described in claim 1, characterized in that, The lower sealing unit gasket is a circular tube structure, and the side wall of the upper cylindrical tube of the lower sealing unit gasket has several evenly distributed second pin holes. The lower setting pin is a shear pin structure. The upper part of the lower setting pin is a cylindrical second pin body, and the outer wall of the second pin body is provided with a thread. The lower part of the lower setting pin is a cylindrical second pin head. The second pin body is installed in the second pin hole of the lower sealing unit gasket through a threaded connection, and the second pin head is inserted into the second countersunk hole of the upper working cylinder.

4. The compression-type dual independent sealing unit packer as described in claim 1, characterized in that, Two semi-circular retaining rings can be combined to form a complete circle; The outer circular surface of the clamp is threaded, the lower end face of the cylindrical groove is in contact with the lower end face of the crescent ring, and the upper end face of the clamp is flush with the upper end face of the crescent ring. The lower gasket of the upper sealing unit is cylindrical. The upper cylindrical sidewall of the lower gasket of the upper sealing unit is evenly provided with a plurality of third pin holes. The inner wall of the lower cylindrical sidewall of the lower gasket of the upper sealing unit is provided with internal threads to achieve threaded connection and fixation with the clamp. The upper end face of the lower gasket of the upper sealing unit is in contact with the lower end face of the upper sealing unit assembly. The coupling pin is a shear pin structure. The upper part of the coupling pin is a cylindrical third pin body, and the outer wall of the third pin body is provided with a thread. The lower part of the coupling pin is a cylindrical third pin head. The third pin body is installed and fixed in the third pin hole of the lower gasket ring of the upper sealing unit by threaded connection. The third pin head is inserted into the third countersunk hole of the upper working cylinder. The lower sealing unit adjusting ring is cylindrical, and the inner wall of the upper cylindrical part of the lower sealing unit adjusting ring is provided with internal threads to achieve threaded connection and fixation with the clamp. The lower end face of the lower sealing unit adjusting ring is in contact with the upper end face of the lower sealing unit assembly. The clamp can completely cover the first annular groove to ensure that the lower end face of the clamp does not scrape against the lower boss surface of the annular groove.

5. The compression-type dual independent sealing unit packer as described in claim 1, characterized in that, The setting force transmission tube is cylindrical, and the upper cylindrical end of the setting force transmission tube is fitted with the outer side of the inlet seat with a clearance fit. The lower cylindrical end of the setting force transmission tube is threadedly connected and fixed to the upper locking connecting ring. The inlet seat is cylindrical, and the outer wall of the middle cylinder of the inlet seat is provided with a first reverse tooth type thread. The lower cylinder of the inlet seat is threadedly connected to the upper working cylinder, and the lower inner surface of the inlet seat is flush with the upper inner surface of the upper working cylinder. The upper sealing unit locking ring is an open circular ring structure. The inner wall surface of the upper sealing unit locking ring is provided with a second reverse tooth type thread. The second reverse tooth type thread and the first reverse tooth type thread are a set of mutually cooperating thread pairs, which can effectively mesh with each other. Due to the influence of the reverse tooth structure, under the action of thrust parallel to the axis, the upper sealing unit locking ring can only move from the upper end of the guide seat to the lower end, and cannot move from the lower end of the guide seat to the upper end. After the seated force transmission tube is connected and fixed to the upper locking connecting ring, a second annular groove is formed on the inner side, and the upper sealing unit locking ring gap is engaged in the second annular groove.

6. The compression-type dual independent sealing unit packer as described in claim 1, characterized in that, The upper working cylinder is cylindrical, and the lower end of the upper working cylinder is connected to the lower locking claw spring by a thread. The outer circle of the lower end of the upper working cylinder is inserted into the lower working cylinder. The mating working surfaces of the upper working cylinder and the lower working cylinder are sealed by a sealing O-ring. The lower working cylinder is cylindrical, and the upper end of the lower working cylinder is threadedly connected to the lower sealing unit gasket. A third annular groove is formed between the lower working cylinder and the lower sealing unit gasket. The upper working cylinder is inserted into the third annular groove. The lower end of the lower working cylinder has a third reverse tooth type thread on its inner wall. The inner circle of the lowermost end of the lower working cylinder is flush with the inner circle of the upper end of the upper working cylinder. The lower locking pawl spring has a cylindrical structure, including an upper pawl portion, a middle connecting portion, and a lower pawl portion from top to bottom; The outer circle of the upper pawl is provided with a threaded thread to connect with the upper working cylinder. The cylinder side wall of the upper pawl is provided with a through hole groove. The threaded thread of the upper pawl is segmented and evenly distributed around the circumference. The upper end face of the upper pawl is in contact with the lower end face of the upper working cylinder unsealing cylinder to which the upper working cylinder belongs. The inner circle of the upper pawl is flush with the inner circle of the upper working cylinder unsealing cylinder. The upper end of the intermediate connecting part is connected to the upper ratchet part, and the lower end of the intermediate connecting part is connected to the lower ratchet part; The lower pawl part is provided with a fourth reverse tooth type thread on the outer circle, and the cylindrical side wall of the lower pawl part is provided with a through hole groove. The fourth reverse tooth type thread is in the shape of segments and is evenly distributed around the circumference. The fourth reverse tooth type threaded thread and the third reverse tooth type threaded thread are a set of mutually cooperating thread pairs, which can effectively mesh with each other. Due to the influence of the reverse tooth structure, under the action of thrust parallel to the axis, the lower locking claw spring can only move from the upper end to the lower end of the lower working cylinder, and cannot move from the lower end to the upper end of the lower working cylinder. Without radial support, the upper pawl applies tension to the upper working cylinder and the lower locking pawl spring respectively. The threaded connection between the upper working cylinder and the lower locking pawl spring will shift relative to each other due to the radial contraction of the upper pawl, and eventually disengage.

7. The compression-type dual independent sealing unit packer as described in claim 1, characterized in that, The unsealing ring is cylindrical and is fitted with a clearance fit on the inner side of the unsealing cylinder of the upper working cylinder and the inner side of the upper pawl of the lower locking claw spring. The unsealing pin is a shear pin structure. The upper part of the unsealing pin is a cylindrical fourth pin body with a threaded thread on the outer wall. The lower part of the unsealing pin is a cylindrical fourth pin head. The fourth pin body is installed in the fourth pin hole of the upper working cylinder by a threaded connection, and the fourth pin head is inserted into the fourth countersunk hole of the unsealing ring.

8. The compression-type dual independent sealing unit packer as described in any one of claims 1-7, characterized in that, The shearing force of the upper setting pin is 1.2-1.5 times that of the lower setting pin.

9. The compression-type dual independent sealing unit packer as described in claim 5, characterized in that, The upper end of the inlet seat is provided with a tapered chamfer to facilitate the guidance of other downhole tools into the packer.

10. The compression-type dual independent sealing unit packer as described in claim 6, characterized in that, The outer circle of the middle connecting part of the lower locking claw spring is lower than the root circle of the fourth reverse tooth type thread of the lower locking claw spring, so as to ensure that the lower locking claw spring can move smoothly through the teeth.

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