Underwater mud line hanger

Abstract

The utility model discloses an underwater mud line hanger which is provided with an outer layer structure, at least one middle layer structure and an inner layer structure, and each middle layer structure is provided with a middle layer hanger and a middle layer sleeve in threaded connection with the lower end of the middle layer hanger. Internal threads are arranged on the inner circumferential surfaces of the upper ends of the middle-layer hanger and the inner-layer hanger, the internal threads are used for being connected with a hanger sending and taking tool, at least one cleaning hole used for being communicated with the space on the inner side and the space on the outer side of the hanger is formed in the upper end of the middle-layer hanger, and the cleaning hole is formed in the position where the internal threads on the middle-layer hanger are located. The hanger delivering and taking tool can seal and shield the cleaning hole. Space on the inner side and space on the outer side of the hanger are communicated through the cleaning holes, redundant cement is discharged from the cleaning holes through forward washing or reverse washing operation after well cementation, a hanger delivery and taking tool can be taken down conveniently, meanwhile, the sealing face of the hanger can be cleaned preliminarily, and installation and detachment are convenient.

Description

Technical Field

[0001] The utility model relates to the technical field of oil and gas exploitation, in particular to an underwater mud line hanger. Background Art

[0002] In recent years, my country's demand for the use of mineral resources such as oil and natural gas has been increasing. In order to meet the increasing energy demand, it is imperative to vigorously develop the development technology of submarine oil and gas resources. In the process of developing offshore oil platform mining technology, some offshore oil platforms are limited by the huge load given by the weight of the pipe string and cannot support the development of deep oil and gas resources. If the oil well is too deep, the pipe string is too heavy and the platform cannot bear the weight of the pipe string. This is why an underwater mudline hanger technology is often used to assist the seabed in bearing the weight. However, this technology also has some problems that need to be improved.

[0003] After drilling is completed, the underwater wellhead sometimes needs to be temporarily abandoned, so a removable temporary well abandonment cap is needed to seal the pressure in the well during the abandonment period. However, it is difficult to control the cementing height with conventional mudline hangers, which may cause cement to overflow the mudline hanger delivery tool, resulting in the delivery tool being unable to be removed smoothly and the temporary well abandonment cap being unable to be installed. In addition, after cementing, there will be certain debris on the sealing surface between the hanger delivery tool and the hanger, affecting the sealing performance. Utility Model Content

[0004] The utility model aims to solve the above problems and designs an underwater mud line hanger, which can effectively solve the problem that the traditional mud line hanger is difficult to remove the hanger delivery tool, which affects the installation of the abandoned well cap.

[0005] To achieve the above-mentioned purpose, the technical solution of the utility model is as follows: an underwater mudline hanger, comprising an outer layer structure, a middle layer structure and an inner layer structure, wherein the outer layer structure comprises an upper outer conduit, a lower outer conduit and a bearing pipe connecting the upper outer conduit and the lower outer conduit, the middle layer structure comprises at least one layer, each layer of the middle layer structure comprises a middle layer hanger and a middle layer casing threadedly connected to the lower end of the middle layer hanger, the inner layer structure comprises an inner layer hanger and an inner layer casing threadedly connected to the lower end of the inner layer hanger, the middle layer hanger seat is hung on the bearing pipe, and the inner layer hanger seat is hung on the middle layer hanger,

[0006] The inner circumferential surfaces of the middle-layer hanger and the upper ends of the inner-layer hanger are provided with internal threads, and the internal threads are used to connect the hanger delivery and retrieval tool. The upper end of the middle-layer hanger is provided with at least one cleaning hole for connecting the spaces inside and outside the hanger. The cleaning hole is arranged at the position of the internal threads on the middle-layer hanger, and the hanger delivery and retrieval tool can form a sealing cover for the cleaning hole.

[0007] Preferably, the middle layer structure has three layers, including a first middle layer structure, a second middle layer structure and a third middle layer structure from the outside to the inside, wherein the lower end of the middle layer hanger in the third middle layer structure is threadedly connected to a hanger joint, the lower end of the hanger joint is threadedly connected to the middle layer casing, and the inner layer hanger seat is hung on the hanger joint.

[0008] Preferably, a seat for supporting the middle-layer hanger is formed on the inner circumferential surface of the supporting tube, and a circle of steps is formed on the outer circumferential surface of the middle-layer hanger in the first-layer middle-layer structure, and the step seat is hung on the seat.

[0009] Preferably, the middle-layer hangers in the second-layer middle-layer structure and the third-layer middle-layer structure and the inner-layer hangers are all sleeved with bearing rings, and a plurality of axial vertical grooves are evenly distributed in the circumferential direction of the upper and lower ends of the bearing rings, and the plurality of vertical grooves at the upper end of the bearing rings and the vertical grooves at the lower end are distributed at intervals, a circle of hanging platforms are arranged on the outer circumferential surface of the upper end of the bearing rings, and the middle-layer hangers in the first-layer and second-layer middle-layer structures and the hanger joints in the third-layer middle-layer structure are provided with grooves matching the hanging platforms, and the hanging platform seat is hung in the grooves.

[0010] Preferably, a circle of protrusions cooperating with the bearing ring is arranged on the outer circumference of the middle layer hanger and the inner layer hanger, and the bearing ring is located below the protrusions and can abut against the protrusions.

[0011] Preferably, the middle layer hanger and the inner layer hanger are both connected with retaining rings through threads, the retaining rings are located below the load-bearing rings, the retaining rings and the load-bearing rings are connected through steel belts, and fracture openings are provided on both sides of the steel belts.

[0012] Preferably, the cleaning hole is located at a position higher than the step or the carrying ring.

[0013] Preferably, the upper ends of the upper outer conduit, the middle layer hanger and the inner layer hanger are also threadedly connected with an abandoned well cap, and the abandoned well cap can form a seal on the top of the outer layer structure, the middle layer structure and the inner layer structure.

[0014] Compared with the prior art, the beneficial effects are:

[0015] The utility model connects the spaces on the inner and outer sides of the hanger through the cleaning hole, and discharges excess cement from the cleaning hole through forward or backwashing operation after cementing, so that the cement line is lowered to below the hanger delivery and retrieval tool. After the cleaning is completed, the hanger delivery and retrieval tool will seal the cleaning hole, and wait for the cement to solidify so as to remove the hanger delivery and retrieval tool. At the same time, the sealing surface of the hanger can also be preliminarily cleaned. After temporary abandonment of the well, it is necessary to seal the pressure in the well and facilitate disassembly and assembly. At this time, the hanger delivery and retrieval tool can be removed and a well abandonment cap can be installed, which is relatively convenient for installation and disassembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional structural schematic diagram of the utility model;

[0017] Figure 2 It is a schematic diagram of the explosion structure of the utility model;

[0018] Figure 3 It is a schematic diagram of the structure of the load-bearing ring and the retaining ring in the utility model;

[0019] Figure 4 It is an installation step diagram of the utility model.

[0020] In the figure, 1, 30" guide tube; 2, 30" bearing tube; 21, seat; 3, 20" hanger; 31, step; 4, 20" casing; 5, 20" hanger delivery and retrieval tool; 6, 13-3 / 8" hanger; 7, bearing ring; 701, vertical groove; 8, 13-3 / 8" casing; 9, 13-3 / 8" hanger delivery and retrieval tool; 10, retaining ring; 11, 9-5 / 8" hanger; 12, hanger joint; 13, 9-5 / 8" hanger delivery and retrieval tool; 14, 9-5 / 8" casing; 15, 7" hanger; 16, 7" hanger delivery and retrieval tool; 17, 7" casing; 18, steel belt; 181, fracture opening; 19, abandoned well cap; 101, cleaning hole; 301, groove. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] like Figure 1 As shown, a preferred embodiment of the utility model proposes an underwater mudline hanger, which has at least three stacked structures: an outer layer, a middle layer, and an inner layer, wherein the middle layer structure has at least one layer. In this embodiment, the middle layer structure has three layers, and the overall structure of the mudline hanger has five layers. The following takes the structure of 30″ guide tube 1, 20″ casing 4, 13-3 / 8″ casing 8, 9-5 / 8" casing 14, and 7″ casing 17 as an example. The remaining tubing flow oil and gas wells can also use the mudline hanger structure to suspend the weight of the tubing in the well under the seabed.

[0023] like Figure 2As shown, the outer structure includes a 30" supporting tube 2 and a 30" conduit 1. The upper and lower ends of the 30" supporting tube 2 are respectively welded to the 30" conduit 1. The 30" supporting tube 2 is used to hang the middle structure. A circle of seating platform 21 is formed on the inner circumference of the 30" supporting tube 2, which protrudes inwardly. The upper end surface of the seating platform 21 is a conical surface.

[0024] The middle-layer structure mainly includes three layers, namely the first middle-layer structure, the second middle-layer structure and the third middle-layer structure. The outer structure, the third middle-layer structure and the inner structure are installed step by step.

[0025] refer to Figure 2 The first middle structure includes a 20″ hanger 3, a 20″ casing 4 and a 20″ hanger delivery tool 5. An internal thread is provided on the inner circumferential surface of the upper end of the 20″ hanger 3, and an external thread matching the internal thread is provided on the outer circumferential surface of the lower end of the 20″ hanger delivery tool 5. The upper end of the 20″ hanger 3 is threadedly connected to the 20″ hanger delivery tool 5, and the lower end is threadedly connected to the 20″ casing 4. The upper end of the 20″ hanger delivery tool 5 is threadedly connected to another 20″ casing 4. A circle of steps 31 is provided on the outer circumferential surface of the 20″ hanger 3, and the lower side surface of the step 31 is an inclined surface, which matches the seat 21 on the inner side of the 30″ load-bearing tube 2. When installed, the step 31 is hung on the seat 21.

[0026] A circle of grooves 301 are arranged on the inner circumference of the 20″ hanger 3. The grooves 301 are in the shape of two steps 31 and are used to hang the second middle structure.

[0027] refer to Figure 2 The second middle layer structure includes a 13-3 / 8″ hanger 6, a 13-3 / 8″ casing 8 and a 13-3 / 8″ hanger delivery and retrieval tool 9. The inner circumferential surface of the upper end of the 13-3 / 8″ hanger 6 is provided with an internal thread, and the outer circumferential surface of the lower end of the 13-3 / 8″ hanger delivery and retrieval tool 9 is provided with an external thread. The upper end of the 13-3 / 8″ hanger 6 is threadedly connected to the 13-3 / 8″ hanger delivery and retrieval tool 9, and the lower end is threadedly connected to the 13-3 / 8″ casing 8. The upper end of the 13-3 / 8″ hanger delivery and retrieval tool 9 is threadedly connected to another 13-3 / 8″ casing 8.

[0028] A load ring 7 is sleeved on the 13-3 / 8″ hanger 6 and is connected with a retaining ring 10 through threads. At the same time, a circle of protrusions is provided on the outer circumference of the 13-3 / 8″ hanger 6. The retaining ring 10 is located below the load ring 7. The load ring 7 and the retaining ring 10 are connected by two steel belts to fix the position of the load ring 7.

[0029] refer to Figure 3A plurality of axial vertical grooves 701 are evenly distributed at the upper and lower ends of the load ring 7, wherein the plurality of vertical grooves 701 at the upper end of the load ring 7 and the plurality of vertical grooves 701 at the lower end are distributed at intervals, so that the plurality of vertical grooves 701 at the upper end of the load ring 7 are distributed in an m-shape, and the plurality of vertical grooves 701 at the lower end are distributed in an inverted m-shape, so that the load ring 7 has a certain tension. A plurality of suspension platforms are arranged on the outer peripheral surface of the upper end of the load ring 7, and the suspension platforms are of a stepped structure, and the suspension platforms can be engaged with the groove 301.

[0030] A steel belt 18 is provided on both sides of the load-bearing ring 7, the upper end of the steel belt 18 is fixedly connected to the load-bearing by screws, and the lower end of the steel belt 18 is fixedly connected to the retaining ring 10 by screws. Under the pulling of the steel belt 18, a part of the suspension platform on both sides of the load-bearing ring 7 will expand outward so that the suspension platform seat can be hung in the groove 301.

[0031] There are breaking openings 181 on both sides of the steel belt 18 near the lower end, and the steel belt 18 will break at the breaking openings 181 under the action of tension. When the 13-3 / 8" casing 8 is lowered into the 20" casing 4, the hanging platform outside the load ring 7 enters the groove 301 inside the 20" hanger 3, and the 13-3 / 8" hanger 6 and the retaining ring 10 continue to move downward, breaking the steel belt 18 until the 13-3 / 8" hanger 6 is hung in place.

[0032] refer to Figure 2 The third middle structure includes a 9-5 / 8" hanger 11, a 9-5 / 8" casing 14, a 9-5 / 8" hanger delivery tool 13 and a 9-5 / 8" hanger 11 joint. The connection method is basically the same as the connection method of the above-mentioned casings and hangers. The difference is that the lower end of the 9-5 / 8" hanger 11 is threadedly connected to the 9-5 / 8" hanger 11 joint, and the lower end of the 9-5 / 8" hanger 11 joint is threadedly connected to the 9-5 / 8" casing 14. The 9-5 / 8" hanger 11 joint is used to hang the inner structure.

[0033] The outer side of the 9-5 / 8" hanger 11 is also provided with a load ring 7, a retaining ring 10 and a steel belt 18. The structure, connection method and principle are the same as those described above and will not be described in detail here. A two-step stepped groove 301 is formed on the inner circumference of the joint of the 9-5 / 8" hanger 11, which is used to hang the inner layer structure.

[0034] refer to Figure 2 The inner structure includes a 7″ hanger 15, a 7″ casing 17 and a 7″ hanger delivery and retrieval tool 16, wherein the inner circumferential surface of the upper end of the 7″ hanger 15 is provided with an internal thread, and the outer circumferential surface of the lower end of the 7″ hanger delivery and retrieval tool 16 is provided with an external thread, the 7″ hanger 15 is threadedly connected to the 7″ hanger delivery and retrieval tool 16, and the lower end is threadedly connected to the 7″ casing 17.

[0035] The outer side of the 7″ hanger 15 is also provided with a load ring 7, a retaining ring 10 and a steel belt 18. The structure, connection method and principle are the same as those described above, and will not be described in detail here.

[0036] In this example, at least one cleaning hole 101 is provided at the upper end of each layer of the hanger, preferably multiple cleaning holes 101 are evenly distributed around the hanger. The cleaning hole 101 can connect the spaces on the inner and outer sides of the hanger. The location of the cleaning hole 10 should be higher than the location of the seat step or the support ring 7. The relative position of the cleaning hole 101 and the upper internal thread of the hanger need to be preset to ensure that the retracting thread of the hanger delivery tool can expose the cleaning hole 101. In this way, when cleaning is required, it is only necessary to retract the hanger delivery tool upwards for a certain distance to expose the cleaning hole 101, and then start the cleaning work to clean off the excess cement so as to install the abandoned well cap 19. After the cement cleaning is completed, it is necessary to lower the cleaning tool to focus on cleaning the sealing surface of the hanger.

[0037] After cleaning is completed, the hanger delivery tool can be further tightened downwards to tighten the connection thread between the hanger delivery tool and the hanger to the set torque, thereby activating the seal between the hanger delivery tool and the hanger. The outer wall of the hanger delivery tool can cover the cleaning hole 101, so that the inner and outer spaces of the hanger can be isolated.

[0038] After each of the five-layer structures of the mudline hanger is hung to the tail position, it is cleaned once, and then cement needs to be filled in the gaps between each layer of the structure to fix each layer of the structure. When it is necessary to abandon the well, it is only necessary to remove the hanger delivery tool layer by layer from the inside to the outside, and then tighten the abandonment cap 19 layer by layer to seal the upper end of each layer of the structure.

[0039] The 30″ guide tube 1 of the mudline hanger is fixed in the seabed, so the seabed can be used to bear the weight of the wellbore pipe string of the submarine wellhead, share the weight load of the pipe string on the offshore platform, and increase the stability and safety of the offshore oil production platform. In this way, the offshore oil production platform can hang a longer and heavier pipe string, drill deeper oil / gas wells, and develop deeper oil and gas reservoirs.

[0040] refer to Figure 4 The specific installation steps of the mudline hanger are as follows (this step is only the equipment installation step, ignoring the drilling process):

[0041] (1) Lower the 30″ guide tube 1 with the support tube.

[0042] (2) Connect the 20″ casing 4, the 20″ hanger delivery tool 5 and the 20″ hanger 3, lower the 20″ casing 4, and fix the 20″ casing 4 after the hanging is completed.

[0043] (3) Remove excess cement through the cleaning hole 101 on the 20″ hanger 3.

[0044] (4) Connect the 13-3 / 8″ casing 8, the 13-3 / 8″ hanger delivery tool 9 and the 13-3 / 8″ hanger 6, and lower the 13-3 / 8″ casing 8. After the mounting is completed, fix the 13-3 / 8″ casing 8.

[0045] (5) Remove excess cement through the cleaning hole 101 on the 13-3 / 8″ hanger 6.

[0046] (6) Connect the 9-5 / 8″ casing 14, the 9-5 / 8″ hanger delivery tool 13 and the 9-5 / 8″ hanger 11, and lower the 9-5 / 8″ casing 14. After the mounting is completed, fix the 9-5 / 8″ casing 14.

[0047] (7) Remove excess cement through the cleaning hole 101 on the 9-5 / 8″ hanger 11.

[0048] (8) Connect the 7″ casing 17, the 7″ hanger delivery tool 16 and the 7″ hanger 15, lower the 7″ casing 17, and fix the 7″ casing 17 after the mounting is completed.

[0049] (9) Remove excess cement from the well using the cleaning hole 101 on the 7″ hanger 15.

[0050] (10) After cementing is completed, the 7″ hanger delivery tool 16 is removed and the 7″ abandonment cap 19 is installed.

[0051] (11) Remove the 9-5 / 8″ hanger delivery tool 13 and install the 9-5 / 8″ abandoned well cap 19.

[0052] (12) Remove the 13-3 / 8″ hanger delivery tool 9 and install the 13-3 / 8″ abandoned well cap 19.

[0053] (13) Take out the 20″ hanger delivery tool 5 and install the 20″ abandoned well cap 19.

[0054] (14) Install the 30″ abandoned well cap 19.

[0055] The above technical solutions only reflect the preferred technical solutions of the technical solutions of the utility model. Some changes that may be made to certain parts thereof by technicians in this technical field all reflect the principles of the utility model and fall within the protection scope of the utility model.

Claims

1. An underwater mudline hanger, comprising an outer layer structure, a middle layer structure and an inner layer structure, wherein the outer layer structure comprises an upper outer conduit, a lower outer conduit and a supporting tube connecting the upper outer conduit and the lower outer conduit, the middle layer structure comprises at least one layer, each layer of the middle layer structure comprises a middle layer hanger and a middle layer casing threadedly connected to the lower end of the middle layer hanger, the inner layer structure comprises an inner layer hanger and an inner layer casing threadedly connected to the lower end of the inner layer hanger, the middle layer hanger seat is hung on the supporting tube, the inner layer hanger seat is hung on the middle layer hanger, and the characteristic is that The inner circumferential surfaces of the middle-layer hanger and the upper ends of the inner-layer hanger are provided with internal threads, and the internal threads are used to connect the hanger delivery and retrieval tool. The upper end of the middle-layer hanger is provided with at least one cleaning hole for connecting the spaces inside and outside the hanger. The cleaning hole is arranged at the position of the internal threads on the middle-layer hanger, and the hanger delivery and retrieval tool can form a sealing cover for the cleaning hole.

2. An underwater mudline hanger according to claim 1, characterized in that: The middle layer structure has three layers, which include a first middle layer structure, a second middle layer structure and a third middle layer structure from the outside to the inside, wherein the lower end of the middle layer hanger in the third middle layer structure is threadedly connected to a hanger joint, the lower end of the hanger joint is threadedly connected to the middle layer casing, and the inner layer hanger seat is hung on the hanger joint.

3. An underwater mudline hanger according to claim 2, characterized in that: The inner circumferential surface of the supporting tube is protruded inwardly to form a seat for supporting the middle-layer hanger, and the outer circumferential surface of the middle-layer hanger in the first-layer middle-layer structure is formed with a circle of steps, and the step seat is hung on the seat.

4. An underwater mudline hanger according to claim 2, characterized in that: The middle-layer hangers in the second-layer middle-layer structure and the third-layer middle-layer structure and the inner-layer hangers are all sleeved with bearing rings, and a plurality of axial vertical grooves are evenly distributed in the circumferential direction at the upper and lower ends of the bearing rings, and the plurality of vertical grooves at the upper end of the bearing rings and the vertical grooves at the lower end are distributed at intervals, and a circle of hanging platforms are arranged on the outer circumferential surface of the upper end of the bearing rings, and the middle-layer hangers in the first-layer and second-layer middle-layer structures and the hanger joints in the third-layer middle-layer structure are provided with grooves matching with the hanging platforms, and the hanging platform seats are hung in the grooves.

5. An underwater mudline hanger according to claim 4, characterized in that: A circle of protrusions matching with the bearing ring is arranged on the outer peripheral surfaces of the middle layer hanger and the inner layer hanger. The bearing ring is located below the protrusions and can abut against the protrusions.

6. An underwater mudline hanger according to claim 4, characterized in that: The middle layer hanger and the inner layer hanger are both connected with retaining rings through threads. The retaining rings are located below the load-bearing rings. The retaining rings are connected to the load-bearing rings through steel belts. Fracture openings are arranged on both sides of the steel belts.

7. An underwater mudline hanger according to claim 3, characterized in that: The cleaning hole is located at a position higher than the step or the carrying ring.

8. The underwater mudline hanger according to claim 1, characterized in that: The upper ends of the upper outer conduit, the middle layer hanger and the inner layer hanger are also threadedly connected with an abandoned well cap, and the abandoned well cap can form a seal on the top of the outer layer structure, the middle layer structure and the inner layer structure.

Images