NO344026B1

NO344026B1 - A protective sleeve arrangement

Info

Publication number: NO344026B1
Application number: NO20170119A
Authority: NO
Inventors: Jens Olav Myklebust
Original assignee: Dwellop As
Priority date: 2017-01-26
Filing date: 2017-01-26
Publication date: 2019-08-19
Also published as: NO20170119A1

Description

Technical Field

[0001] The present invention relates to a device for protecting parts of a riser system from debris, sand, chemicals, impacts or other detrimental elements that could have a negative influence on the part to be protected.

[0002] More specifically the invention relates to a protective sleeve that is to be arranged within drilling, production or injection riser that is coupled to an oil or gas well, and which can be positioned to cover the part to be protected.

Background Art

[0003] It is known to land such a protective sleeve within the riser so that the protective sleeve covers the height of a shear seal, or cutting valve as it is sometimes called, to prevent debris or sand to enter clearances within the seal. Such debris or sand can be detrimental to the functioning of the seal, which has to function properly in the case of an emergency shutdown of the well.

[0004] This known device functions fine as soon as it is installed; that is up to the time when the shear seal has to be tested for integrity.

[0005] When testing the shear seal integrity, inter alia sealing capability, it is not a desire to cut the protective sleeve. That would mean putting unnecessary wear on the shear seal and having to replace the protective sleeve after the testing has been completed.

[0006] Hence, the protective sleeve has to be removed before the testing is performed to save this from being destroyed by the shear seal. To remove the protective seal, the riser has to be disconnected above the sleeve and a retrieving tool has to be lowered through the open top of the riser to lift the sleeve out of the riser. Then the disconnected part of the riser has to be connected again to perform the testing.

[0007] After the testing, the riser has to be opened at the top again and the protective sleeve has to be reinserted before the riser is closed again.

[0008] This operation is time consuming, and the costs have been estimated to about NOK 900 000. Consequently, there is a need for a less time consuming and less costly way of protecting the shear seal or other component prone to deterioration due to debris, sand, wear or other negative influences.

Summary of invention

[0009] The present invention has as its main objective to avoid having to open the riser at the top to facilitate testing of the protected component.

[0010] A further objective is to avoid removal of the protective sleeve from the riser when the protected component is to be teste.

[0011] A still further objective is to provide a protective sleeve that can be easily shifted between a position where it provides protection for the component to be protected, and a position where it is clear from the component to be protected.

[0012] A yet further objective is to provide a sleeve that can be easily displaced within the bore of the riser in the longitudinal direction of the riser.

[0013] There are known slidable sleeves that are capable of acting as valves and opens or closes a port if shifted in one or the other longitudinal direction. These are usually positioned deep in the well.

[0014] One example is known from US 2010/0230109, which shows a surfacecontrolled subsurface safety valve (SCSSV) with a sleeve part that can be shifted downward by applying a hydraulic pressure in a control line. The sleeve, when being displaced downward, will push open a valve. When the hydraulic pressure in the control line is relieved, a spring will force the sleeve part upwards. This known sleeve is not designed to be a protective sleeve, it contains many parts that makes it unsuitable as a protective sleeve, such as the return coil spring.

[0015] The above and other objectives of the invention are achieved by a protective sleeve that interacts with the interior of the riser to form a first hydraulic pressure chamber and a second hydraulic pressure chamber, and that a higher pressure in the first hydraulic pressure chamber than in the second hydraulic pressure chamber will displace the protective sleeve in a first longitudinal direction within the riser and vice versa.

[0016] Other examples of prior art, which do not solve the above problems are:

[0017] US 2006/0219410 A1, which discloses a tool for cleaning of a riser pipe. The tool can be extracted from the pipe while fluid is being pumped down the internal bore. Extraction of the tool and frictional contact of a wiper and internal surface of the riser pipe cause the sleeve to move to a first position. In this position, bypass channels are closed and the fluid pumped down the internal bore and returning in the annulus acts upon a rear portion of the sleeve.

[0018] US 2015/0233196 A1, which discloses a riser displacement and cleaning tool assembly comprising a running tool attachable to a work string, and a fluid displacing body supported upon the running tool. The fluid displacing body has a head portion provided with an opening to accommodate relative movement of the fluid displacing body with respect to the work string, and also has flexible wiper elements providing dynamic sealing contact with adjacent surfaces of the work string and a riser. The fluid displacing body has a skirt depending from the head portion and enclosing a chamber for receiving a fluid. The fluid displacing body is adapted to sealingly engage the riser and the string and is selectively releasable from an initial configuration where the fluid displacing body is supported by the running tool to an operational configuration where the fluid displacing body is axially displaceable from the running tool by introduction of a fluid to the chamber.

[0019] US 7765 632 B2, discloses a tool for cleaning subsea conduits, such as unjacketed risers or risers jacketed with strakes or other vortex induced vibration suppression devices.

Brief description of drawings

[0020]

Figure 1 shows a part of a riser with a shear seal and a protective sleeve within the riser in a retracted position,

Figure 2 shows the same components as in figure 1, but with the protective sleeve in protection position,

Figure 3 shows a detail of the top of the protective sleeve and a section of the riser around an upper hydraulic channel through the riser,

Figure 4 shows a detail of the protective sleeve and a section of the riser around a lower hydraulic channel,

Figure 5 shows a section of the riser containing the protective sleeve,

Figure 6 shows a hydraulic hand pump station for controlling the hydraulic pressure in sleeve displacement chambers, and

Figure 7 shows a schematic hydraulics diagram for the hydraulic control system of the protective sleeve.

Detailed description of the invention

[0021] Figure 1 shows a part of a riser 1, which is connected to the top of a shear seal 2. The riser continues from the bottom of the shear seal 2, but this part is not shown.

[0022] The riser 1 also continues from the upper end of the shown riser part 1. At the upper end various tools can be connected, such as well intervention tools with a lubricator coupled to the riser and a wireline tool extending through the lubricator and down the riser.

[0023] A protective sleeve 3 is arranged within the riser. In the view of figure 1, the sleeve is in the upper position, which means that the lower end 3a is not interfering with the path of the shear seal 2 cutting and closing element.

[0024] In figure 2, the protective sleeve 3 is in the lower position, with a stinger section 4 extending through the bore of the shear seal 2. The stinger section 4 prevents debris, sand or other detrimental components from entering into clearances or collect on surfaces of the shear seal 2.

[0025] The protective sleeve 3 is displaced between the upper and lower positions by hydraulic pressure. To this end first and second hydraulic pressure chambers are defined between the sleeve 3 and the inner surface of the riser 1. The first hydraulic pressure chamber 5 is extends between a lower seal 6 mounted on the inside of the riser 1 and a sleeve seal 7 mounted on the outside of the sleeve 3. The second hydraulic pressure chamber 8 extends between an upper seal 9 mounted on the inside of the riser 1 and the sleeve seal 7.

[0026] The seals are shown in greater detail in the detailed drawings of figures 3 and 4, which show a detail A and B of figure 1.

[0027] Figures 3 and 4 also show a first hydraulic port 10 that supplies hydraulic pressure to the first hydraulic pressure chamber 5, and a second hydraulic port 11 that supplies hydraulic pressure to the second pressure chamber 8. In figure 4, the first hydraulic pressure chamber 5 is very short, as the sleeve 3 is in its lowermost position.

[0028] Also shown in figure 3 is a scraping seal 12 mounted on the sleeve 3 near the upper end 3b of the sleeve 3. This scraping seal 12 acts to remove debris from the inside of the riser 1 when the sleeve 3 is moved upwards. This reduces greatly the risk of debris finding its way across the upper seal 9.

[0029] The sleeve seal 7 thus acts as a piston, which can move between the lower seal 6 and the upper seal 9. If hydraulic fluid is supplied under pressure through the first port 10, the sleeve seal 7 and hence the protective sleeve 3, will be moved upwards.

[0030] If hydraulic fluid is supplied under pressure through the second port 11, the sleeve seal 7 and hence the protective sleeve 3, will be moved downwards.

[0031] The seals 6, 7, 9 and 12 may conveniently be mounted in grooves formed on the inside of the riser 1 or on the outside of the sleeve 3.

[0032] Figure 5 shows a riser part 1 containing the protective sleeve 3. As can be seen in the figure, the stinger section 4 of the protective sleeve 3, which is to cover the length of the shear seal, protrudes from the riser section 1.

[0033] The riser part 1 comprises a lower riser section 1a and an upper riser section 1b. The two sections 1a, 1b are connected by a pair of flanges 13a, 13b. As also can be seen in figures 1 and 2, the upper seal 9 is situated in the upper riser section 1b. By disconnecting the riser part 1 at the flanges 13a and 13b, it is possible to insert the protective sleeve 3 so that the sleeve seal 7 becomes situated between the upper seal 9 and the lower seal 6, and hence can move between these.

[0034] A set of lower control valves 14a is arranged on the outside of the lower section 13a and a set of upper valves 14b are arranged on the outside of the upper section 13b. The valves are coupled to the ports 10, 11. A protective cover 15 is arranged outside of the valves and attached to the riser part 1.

[0035] Figure 6 shows a control module in the form of a hand pump station 16. It comprises two hand pumps 17a and 17b, which are hydraulically coupled to a respective valve set 14a and 14b. When the first hand pump 14a is used, hydraulic fluid is pumped through valves in the first valve set 14a and into the lower chamber 5 to increase the pressure in this chamber. At the same time, pressure is relieved from the upper chamber 8 to be drained to an hydraulic reservoir (se figure 7). As a result, the protective sleeve 3 is shifted upwardly within the riser part 1.

[0036] If the second hand pump 14b is operated hydraulic fluid will in an equivalent manner be pumped into the upper chamber 8. At the same time the lower chamber 5 will be drained.

[0037] Figure 7 shows a schematic hydraulic diagram of the hydraulic system for controlling the protective sleeve 3.

[0038] The protective sleeve is shown schematically as piston rod 3 in a double acting piston. The sleeve seal 7 is shown as the double acting piston 7. The riser part is shown as a cylinder 1, and the upper and lower seals are shown as end caps 6 and 8. These define the upper and lower chambers 5 and 8.

[0039] The hand pumps 17a and 17b are shown. These are coupled to a respective chamber 5, 8 through a valves. The valves comprise two-way twoposition needle valves 18a, 18b, which are opened to let hydraulic pressure into the chambers 5, 8. The valves 18a, 18b are controlled by a control valve 19, which when opened will set both valves 18a and 18b to open position. The hydraulic pressure also goes through one of two piloted check valves 20a, 20b. If the check valve 20a is subjected to pump pressure from the hand pump 17a, it will open, but at the same time force the check valve 20b into a closed position. Return hydraulic fluid from the upper chamber 8 will therefore be returned through a relief valve 21b. Equivalent to this hydraulic fluid from the lower chamber 5 will be returned through a relief valve 21a.

[0040] When the protective sleeve 3 is not to be shifted, the pump station may be disconnected from the valves by quick disconnections 22. The hydraulic lines may also be closed by hand operated stop valves 23 to retain the hydraulic pressure within the chambers 5, 8.

Claims

1. A protective sleeve arrangement for protecting parts of a riser system from debris, sand, chemicals, impacts or other detrimental elements that could have a negative influence on the part to be protected, comprising a protective sleeve (3) arranged within a riser (1), wherein said sleeve (3) interacts with the interior of said riser (1) to form a first hydraulic pressure chamber (5) and a second hydraulic pressure chamber (8), and that a higher pressure in the first hydraulic pressure chamber (5) than in the second hydraulic pressure chamber (8) will displace the protective sleeve (3) in a first longitudinal direction within the riser (1) and vice versa.

2. The protective sleeve arrangement of claim 1, wherein said protective sleeve (3) in a first longitudinal position extends through the bore of a shear seal (2).

3. The protective sleeve arrangement of claim 1 or 2, wherein it comprises a first seal (6) mounted on the inside of the riser part, to seal off one end of the first hydraulic pressure chamber (5), a second seal (9) mounted on the inside of the riser part, to seal off one end of the second hydraulic pressure chamber (8), and a sleeve seal (7) mounted on the protective sleeve (3) and arranged between said first and second seal (6, 9), and thereby defining a division between the first and the second hydraulic pressure chambers (5, 8).

4. The protective sleeve arrangement of claim 3, wherein a flanged connection (13a, 13b) between riser sections is situated between the first and the second seals (6, 9).