Method of inserting a device in a subsea oil well, method of removing a device from a subsea oil well, and system for insertion and removal of a device in a subsea oil well

Abstract

The present invention relates to methods of inserting and removing tools and/or robots into/from inside subsea oil wells. In this scenario, the present invention provides a system for insertion and removal of a device (30) in a subsea oil well (20), said system comprising (i) a WCT assembly (10) comprising a removable protective cap (40) and (ii) a WCT tool (50) connected to a receptacle (60) comprising within it the device (30), wherein the WCT tool (50) is suitable for being inserted in the place where the protective cap (40) is coupled, wherein at least one of receptacle (60) and WCT tool (50) is able to be opened or closed, releasing the device (30) into the subsea oil well (20) or retaining same inside the receptacle (60). The invention further provides methods of inserting and removing a device (30) into/from a subsea oil well (20).

Claims

1. A system for insertion and removal of an autonomous robotic device in a subsea oil well, the system comprising; a wet Christmas tree (WCT) assembly comprising a removable tree cap; and a tree running tool connected to a receptacle comprising within it the autonomous robotic device, wherein the autonomous robotic device comprises at least one set of expandable arms at a first end of the autonomous robotic device, wherein the tree running tool is suitable for being inserted in the place where the tree cap is coupled, wherein at least one of the receptacle and the tree running tool is able to be opened or closed, to release the autonomous robotic device into the subsea oil well or to retain the autonomous robotic device inside the receptacle.

2. The system according to claim 1, wherein the autonomous robotic device comprises a central body, wherein a second set of expandable arms is positioned at a first end of the central body, and two more sets of expandable arms are positioned at a second end of the central body.

3. The system according to claim 2, wherein the first end of the autonomous robotic device is the first end of the central body.

4. The system according to claim 1, wherein each set of expandable arms comprises three expandable arms.

5. The system according to claim 1, wherein each expandable arm is configured as an elastic body of the spring type.

6. The system according to claim 1, wherein each expandable arm comprises two elastic elements joined together at a central point.

7. The system according to claim 6, wherein a sliding wheel is positioned at the central point.

8. The system according to claim 7, further comprising a support for the sliding wheel, and wherein the elastic elements are fixed to the support.

9. The system according to claim 7, wherein the sliding wheels are positioned to be inclined relative to an axis of motion of the autonomous robotic device, and wherein the inclined wheels are configured to produce a helicoidal or bi-helicoidal motion of the autonomous robotic device inside the subsea oil well.

10. The system according to claim 9, wherein the inclined wheels are configured to produce a helicoidal or bi-helicoidalmotion of the autonomous robotic device inside the subsea oil well.

11. The system according to claim 6, wherein each elastic element comprises a spring element with double kink and straight middle.

12. The system according to claim 1, wherein the receptacle comprises a shape corresponding to the shape of the autonomous robotic device.

13. The system according to claim 1, wherein at least one of receptacle and tree running tool is configured for being opened and closed.

14. The system according to claim 1, wherein the receptacle comprises the autonomous robotic device between the sea surface and the sea bed by means of a support vessel and/or ROV.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The detailed description presented hereunder refers to the appended figures and their respective reference numbers.

(2) FIG. 1 shows a sectional view of a WCT assembly and of a subsea oil well where the methods according to the preferred embodiment are applied.

(3) FIG. 2 shows the view in FIG. 1 additionally showing a WCT tool connected to a receptacle comprising within it an autonomous device.

(4) FIG. 3 shows a preferred configuration of the autonomous device.

(5) FIG. 4 shows an isolated view of an expandable arm according to an optional configuration of an autonomous device.

DETAILED DESCRIPTION OF THE INVENTION

(6) To begin with, it is emphasized that the following description is based on a preferred embodiment. However, as will be obvious to a person skilled in the art, the invention is not limited to this particular embodiment.

(7) FIG. 1 shows a sectional view of a wet Christmas tree (WCT) assembly 10 and of a subsea oil well 20 where the methods according to the preferred embodiment are applied.

(8) Firstly, a method of inserting a device, such as an autonomous device 30, in the subsea oil well 20 is provided. A first step of the method according to the preferred embodiment consists of removing a protective cap 40 (known as tree cap) from the WCT assembly 10.

(9) In a second step of the method of insertion, a WCT tool 50 (known as tree running tool), or some other equivalent interface tool, is inserted in the place where the protective cap 40 was previously coupled. The insertion of the WCT tool 50 may comprise coupling the WCT tool 50 to the WCT assembly 10 in the same way that the protective cap 40 was coupled.

(10) Preferably, the WCT tool 50 is connected to a receptacle 60 suitable for receiving within it the autonomous device 30. Preferably, the receptacle 60 comprises a shape corresponding to the shape of the autonomous device 30. In the example shown in FIG. 2 the receptacle 60 and the autonomous device 30 have an elongated shape.

(11) Preferably, the receptacle 60 is able to be opened and closed. More preferably, the bottom end of the receptacle 60 is a closable opening through which the autonomous device 30 passes.

(12) Optionally, the WCT tool 50 is able to be opened and closed, allowing or not allowing passage of the autonomous device 30.

(13) In a third step of the method of insertion, the receptacle 60 and/or WCT tool 50 is opened so as to release the autonomous device 30 into the subsea oil well 20. If both the receptacle 60 and the WCT tool 50 are able to be opened and closed, then both can be opened in this step.

(14) Once the device 30 has been released, it may be preferable to remove the WCT tool 50 and to replace the protective cap 40.

(15) There is further provided a method of removing a device, such as the autonomous device 30, from the subsea oil well 20. A first step of the method of removal according to the preferred embodiment also consists of removing the protective cap 40 from the WCT assembly 10, assuming it has been replaced after the device was introduced. If the WCT tool 50 with the associated receptacle 60 is still attached, this step and the second step mentioned below may be omitted.

(16) In a second step of the method of removal, the WCT tool 50 or some other equivalent interface tool is inserted in the place where the protective cap 40 was previously coupled.

(17) Preferably, the WCT tool 50 is connected to the empty receptacle 60, which is suitable for receiving within it the autonomous device 30.

(18) Finally, the device 30 is guided from inside the subsea oil well 20 to the receptacle 60. If the device is fully autonomous, the step of guiding may happen automatically (i.e. the device 30 may guide itself). Alternatively, the device 30 may be remotely guided by an operator.

(19) Optionally, the receptacle 60 is closed with the autonomous device 30 inside it. Also optionally, the WCT tool 50 is closed, so as to confine the autonomous device 30 in the receptacle 60 even when the receptacle 60 itself is open.

(20) Preferably, the combination or assembly formed by the WCT tool 50 and the receptacle 60 comprising the autonomous device 30 is transported between the sea surface and the sea bed by a support vessel and/or an ROV (Remotely Operated Vehicle).

(21) There is further provided a system for insertion and removal of a device such as an autonomous device 30 in the subsea oil well 20. The system comprises a WCT assembly 10 comprising a removable protective cap 40 and a WCT tool 50 connected to a receptacle 60 comprising within it the autonomous device 30, wherein the WCT tool 50 is suitable for being inserted in the place where the protective cap 40 is coupled.

(22) In the present system, at least one of receptacle 60 and WCT tool 50 is able to be opened or closed, releasing the autonomous device 30 into the subsea oil well 20 or retaining same inside the receptacle 60, depending on the method (insertion or removal) that is being executed.

(23) Preferably, the device is an autonomous device 30 such as an autonomous robot suitable for performing workover operations inside the subsea oil well 20, as illustrated in FIG. 3.

(24) As can be seen in FIGS. 3 and 4, the autonomous device 30 comprises a central body 5 and expandable arms 1. Each expandable arm 1 comprises at least one sliding wheel 2 configured for touching the inside wall of a pipeline.

(25) Optionally, the autonomous device 30 comprises at least one set 9 of expandable arms 1. Each set 9 can comprise three expandable arms 1, for example. The configuration with three expandable arms 1 may be advantageous through allowing better centring thereof, in comparison with other configurations.

(26) In any one of the configurations described, each expandable arm 1 comprises at least one sliding wheel 2 configured for touching the inside wall of the pipeline. In this way, when a configuration with three expandable arms 1 is adopted, three sliding wheels 2 will be adopted, i.e. one for each expandable arm.

(27) In alternative configurations (not shown in the figures) only one set 9 of expandable arms 1 may be adopted. This may be achieved by providing a central body 5 enclosed by the expandable arms 1. In these configurations, three expandable arms 1 are preferably adopted.

(28) FIG. 4 shows an isolated view of an expandable arm 1 according to an optional configuration; in this configuration, the expandable arm 1 is an elastic body of the spring type. More particularly, the expandable arm 1 comprises two elastic elements 11 joined together at a central point. A sliding wheel 2 can be positioned at the central point. In this configuration, a support 3 for the sliding wheel 2 may also be adopted, wherein the expandable arms 1 would be fixed to the support 3.

(29) In this optional configuration, it can be seen that each elastic element 11 comprises a spring element (of the spring assembly type) with double kink and straight middle. In other words, the elastic element 11 is made from a flexible material that can be compressed and then spring back to its original shape. It is thus possible to achieve a configuration whose profile is reduced to comprise a larger range of diameters.

(30) Optionally, the sliding wheels 2 are positioned so that they are inclined relative to the axis of motion of the central body 5 (or, in use, the central axis of the pipeline), so as to produce a helicoidal motion inside the pipeline.

(31) In optional configurations, as shown in FIG. 3, in which four sets 9 of expandable arms 1 are adopted, e.g. with each set 9 having three arms 1, two sets 9 can be positioned before the central body 5 and two sets 9 can be positioned after the central body 5. In these configurations, all the sliding wheels 2 may be inclined, providing two sets 9 of inclined wheels, both in the front portion and in the rear portion. The central body 5 then follows a bi-helicoidal path as it moves through the pipeline, meaning that its traction capacity is twice as great as that of a conventional robot that performs a helicoidal motion.

(32) In this optional configuration, the sets 9 with three expandable arms 1 are joined at the ends of the expandable arms 1 by connecting elements. These elements may be any known connecting elements.

(33) In addition, a linkage 4 may be adopted, connecting together (at each end) the set 9 of expandable arms 1 closest to the central body 5 to the set 9 further away from the central body 5. This linkage 4 may be rigid or flexible, so as to allow rotational and bending movements.

(34) Thus, there are provided methods and a system that dispense with the need for a dedicated rig for this service. In addition, since the device 30 is not resident, it is able to perform maintenance tasks in different subsea oil wells in a practical manner and at low cost.

(35) Countless variations falling within the scope of protection of the present application are permitted. This reinforces the fact that the present invention is not limited to the configurations/particular embodiments described above. As such, modifications of the above-described apparatuses and methods, combinations between different variations as practicable, and variations of aspects of the invention that are obvious to those of skill in the art are intended to be within the spirit and scope of the claims.