Shared actuation system

Abstract

The present invention refers to a shared actuation system to place tools on any subsea valve interface on an oil production station located in a subsea structure, such as a manifold. The system comprises a connection device for connection to the subsea structure, attached to the connection device at least one structural element, all connected to each other through rotary joints, providing at least two degrees of freedom for a distal end of the structure elements where an actuation tool is positioned, for interaction with the valve interfaces on the subsea structure, where the structural elements further is connected to a sail element.

Claims

1. A shared actuation system for positioning a tool relative to several valve interfaces on a subsea structure, the system comprising: a connection device for connection to the subsea structure in one fixed position; three sealed rotary joints; a first structural element connected to the connection device by means of a first and a second of the three sealed rotary joints; a second structural element connected to a distal end of the first structural element by a third of the three sealed rotary joints, providing at least two degrees of freedom for a distal end of the second structural element, the first structural element and the second structural element forming an arm extending from the connection device; a valve actuation tool, for opening and closing valves on the subsea structure, coupled to the distal end of the second structural element such that the valve actuation tool is positioned on an opposite end of the arm from the connection device, the valve actuation tool positioned for interaction with the valve interfaces on the subsea structure; and a sail element connected to a proximal end of the first structural element in order to compensate a weight of the valve actuation tool positioned on an opposite end of the structural elements.

2. The shared actuation system according to claim 1, wherein the connection device comprises a single interface comprising a pin or funnel for interaction with complimentary elements on the subsea structure.

3. The shared actuation system according to claim 1, wherein at least a part of the structural elements is made of composite materials.

4. The shared actuation system according to claim 2, wherein the subsea structure is a manifold.

5. The shared actuation system according to claim 1, further comprising floating elements integral or attached to the system.

6. The shared actuation system according to claim 1, further comprising a control system arranged to operate the rotary joints to position the tool relative to the desired valve interface for interaction with the valve.

7. The shared actuation system according to claim 6, wherein the control system comprises a communication unit for communication with a remote located operator.

8. A subsea system comprising: a subsea structure and a shared actuation system according to claim 1, wherein the shared actuation system is connected to the subsea structure in one fixed position, and there being a rotary joint between the connection device and the structural elements and there being at least two structural elements connected by a rotary joint, arranged such that the tool at the distal end of the structural element may be operated to interact with several valve interfaces arranged around this fixed position and at different radial distances from the fixed position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will hereinafter be described with reference to the accompanying drawings, which represent a schematic and non-limiting form of its scope:

(2) FIG. 1—shared actuation system according to the present invention;

(3) FIG. 2—schematic view of the shared actuation system interface with a manifold according to the present invention;

(4) FIG. 3—schematic view of the weight reduction mechanism of the shared actuation system according to the present invention.

(5) FIG. 4—a second embodiment of the shared actuation system according to the present invention;

(6) FIG. 5—schematic view of the second embodiment of the shared actuation system interface with a manifold according to the present invention;

(7) FIG. 6—schematic view of the weight reduction mechanism of the second embodiment of the shared actuation system according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(8) The invention will be hereinafter described in regard to an application for a subsea structure, such as manifold subsea equipment. In FIGS. 4-6 the components are referenced by the same identification number.

(9) In accordance with the cited Figures, the shared actuation system (1) according to the present invention comprises an actuation tool (2), which displaces through the rotary joints (3, 4, 5) and structural elements (6, 7). Said structural elements (6, 7) have a hydrodynamic profile and connect to a sail element (8), which assists the movement in the subsea environment. The hydrodynamic profile was developed to facilitate the movement inside in the subsea environment, where the forces to the movement of the arm could be minimized. The sail element (8) holds two units (17, 18—FIG. 5) (one on-line and the other one spare) which contain the electronic elements as the robotic motion unit (17) and the robotic drive unit (18) responsible for the autonomous movement of the arm. The shared actuation system articulated to move the tool according to the present invention provides features that allow it to have only one interface to attach the system unlike the Cartesian mechanism proposed by the configuration previously described for the shared actuation system of the prior art.

(10) The interface of the manifold (20) with the shared actuation system of the present invention is performed through the contact of a single element in the actuation system and a single element in the manifold (20). In one characterization of the present invention, said element in the actuation system consists of a pin (9) and said element in the manifold (20) constitutes a funnel (10). Said feature gives the system the advantage of allowing its integration to the manifold (20) only at the end of its assembly, and also the interchangeability between systems and manifolds. Said feature is important in manufacturing situations in scale and replacement of defective units, The equipment is usually designed to be used under deep water (e.g. 1000-2000 m) for many years (e.g. 25 years), the maintenance and installation of this equipment has to be done remotely so is desired a simpler connection as it could be to install and remove the tool easily.

(11) Furthermore, the simplification of the interface with the manifold (20) gives obvious advantages during the replacement operation of the system in the seabed by remotely operated vehicles (ROVs). Said advantage is due to the use of a single interface connection, rather than multiple ones, allowing easy installation and removal of the system. Additionally, to facilitate the replacement operation, the structural elements of the system are constructed of lightweight composite material (11), and filled with floating elements (12) so that the submerged weight of the unit is on average less than 100 kg, with this weight being the acceptable limit by most ROV operators to lift with the handlers (13 and/or 14).

(12) FIG. 4 shows two electrical connectors (15, 16) for the ROV to be able to connect the jumpers to the subsea lines, one for the power unit and the other for the communication to the top-side unit.

(13) Other advantages given by the articulated systems refer to the protection of the mechanisms responsible for the movement for corrosion, growth of lime and magnesium deposits due to cathode protection systems and growth of marine life. In this system, the movement is performed by means of motorized rotary joints and structural elements, which transform the rotary movement of the joints in translation of the end where the tool is operating. Thus, all components that make up the mechanism have sliding moving parts and are contained in rotary joints. Said joints are elements sealed to the external environment and offset by lubricating oil that protects the elements from the effects described above. Note that this protection is not possible or practical to be used in long-range sliding mechanisms that require rails exposed to seawater for the displacement of the mechanism, as contemplated by the prior art.

(14) The strategy of using rotary joints for conducting the translational movements can be observed both for achieving the horizontal movement and for achieving the vertical movement, through the use of a four-bar mechanism.

(15) Another advantage presented by the shared actuation system of the present invention consists of the minimization of the energy needed for the movement of the mechanism. Said reduction is a consequence of the hydrodynamic geometry in the structural elements of the system and the use of a structure with sail format opposite to the structural elements so that the moment imposed by marine currents acting on the system is neutralized.

(16) In this sense, the shared actuation system object of the present invention may be advantageously applied to the execution of other tasks in addition to the valve operation, by the inclusion of appropriate tools in the structure, such as leak detection systems, cameras, sensor readers, transducers, among others. Additionally, said system can be expanded to perform tasks in other subsea equipment as Christmas trees, PLEMs (Pipeline End Manifold), PLETs (Pipeline End Termination), Subsea Separation Systems and others. Said subsea equipment is able to comprise one or more shared actuation systems of the present invention.