Patent Application
20110079395
In a variety of subsea well related applications, hydraulically operated intervention equipment is deployed at the seabed or at other subsea locations. The hydraulically operated equipment requires a relatively large sized multi-hose hydraulic control umbilical with each hydraulic hose in the umbilical designated to control a unique equipment function. For example, two hoses in a hydraulic umbilical can be designated for opening and closing a valve in a subsea test tree. The technique requires the use of a bespoke umbilical and associated spooling/handling equipment able to deploy the umbilical into a drilling riser and down to the subsea equipment. The umbilical is routed down through the drilling riser and coupled to hydraulic porting in a tubing hanger running tool.
In one variation, an electro-hydraulic multiplex control system can be employed to facilitate control of the subsea equipment with fewer hydraulic hoses running from the surface. This type of control system can be operated to redirect hydraulic fluid along a variety of different hydraulic flow paths to control various mechanical functions. However, the electro-hydraulic multiplex control system still requires a hydraulic umbilical that is routed down through the drilling riser to enable operation of the subsea intervention equipment. The appropriate spooling/handling equipment also must be mounted on the surface rig to handle the umbilical, thus requiring substantial, valuable rig space.
In general, the present invention provides a simplified technique for providing subsea hydraulic control. A subsea installation comprises one or more devices that are actuated hydraulically. A simple signal carrier, such as a wireline logging cable, can be routed down to the subsea installation. However, hydraulic fluid for controlling the one or more hydraulic devices in the subsea installation is delivered via an open water umbilical that extends to the subsea installation from a separate workover control system. This unique approach removes the need for a conventional bespoke electro-hydraulic umbilical routed down through a riser, which also removes the need for mounting associated spooling/handling equipment on the surface intervention facility.
Certain embodiments of the invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and:
In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.
The present invention generally relates to a methodology and system for providing simplified subsea hydraulic control. According to one embodiment, a unique approach is provided for supplying pressurized hydraulic control fluids during a subsea intervention operation while minimizing the systems and components required on the intervention surface facility, e.g. intervention vessel. The approach can be used to operate hydraulically actuated devices at a subsea installation that may comprise, for example, a subsea test tree, a horizontal tubing hanger running tool, and/or other downhole equipment.
The present technique utilizes already existing sources of pressurized hydraulic fluid. According to one example, pressurized hydraulic fluid is supplied from an existing source in a client supplied workover control system. The supply of pressurized hydraulic fluid can be used to operate various devices in the subsea installation, such as devices in a subsea test tree, tubing hanger running tool, and other associated downhole equipment. Routing of the pressurized hydraulic fluid can be achieved with a subsea electro-hydraulic control system which is controlled by a simple signal carrier, such as an electrical cable, running inside the drilling riser from the surface intervention facility to the subsea installation. By way of example, the signal carrier may be part of a wireline logging cable.
The technique renders obsolete the need for a bespoke-hydraulic umbilical as used in conventional systems. The outside source of hydraulic fluid also enables replacement of the normal electrical power and control path that exist within a conventional electro-hydraulic umbilical with, for example, a standard wireline heptacable conductor, of the type which normally resides on a drilling rig. Replacement of the conventional electro-hydraulic umbilical with a hydraulic supply path already existing within a client supplied intervention workover control system umbilical greatly improves the speed of the operation. For example, the technique improves the speed at which a subsea test tree, tubing hanger running tool, and well completion can be run in hole. Consequently, expensive rig time is reduced.
The approach described herein further enables routing of a robust, small signal carrier, e.g. a wireline heptacable conductor, that does not use specialized clamps otherwise required for larger umbilicals. The simplified intervention approach further capitalizes on existing infrastructure within the client supplied subsea intervention workover control system and wellhead. Additionally, a typical intervention rig already comprises a permanent wireline logging cable and winch unit which can be used to deploy the signal carrier down along a riser. Because umbilical spooling/handling equipment is not required, the present technique conserves rig space while reducing costs associated with deployment of a bespoke umbilical. The reduction in equipment further reduces failure rates otherwise inherent with complex operating and servicing envelopes and procedures.
Referring generally to
The signal carrier 28 may be run from a surface facility without the hydraulic umbilical or other hydraulic equipment normally used to operate hydraulic components of subsea installation 22. Instead, a pressurized hydraulic fluid is obtained from a client supplied workover control system 34, such as an intervention work over control system used in performing a variety of subsea intervention operations. The work over control system 34 comprises an open water umbilical 36 that is routed down to subsea installation 22 through the open water to provide a hydraulic fluid supply for operating components on subsea installation 22.
The umbilical 36 may be connected to an umbilical winch 38 of a workover control system unit 40 positioned on a separate surface facility. Depending on the subsea installation 22, open water umbilical 36 comprises a plurality of hydraulic tubes or hoses used to operate the one or more hydraulic devices within subsea installation 22.
As illustrated, umbilical 36 is routed down to an electro-hydraulic control system 42 of subsea installation 22. The umbilical 36 may be routed to electro-hydraulic control system 42 through a production control system pod 44 of workover control system 34. In this embodiment, electro-hydraulic control system 42 also is connected to signal carrier 28 and is positioned beneath tubing hanger running tool 26 and subsea test tree 24. The electro-hydraulic control system 42 may be selectively controlled/actuated via appropriate signals sent through signal carrier 28. As a result, hydraulic control fluid from workover control system 34 is selectively used and routed up through subsea installation 22 to desired hydraulically actuatable devices, as represented by arrow 46.
Referring generally to
In the embodiment illustrated in
In this example, hydraulic control fluid is again supplied through open water umbilical 36 of the client supplied workover control system 34. For example, the umbilical 36 may be connected to workover control system unit 40 mounted on a workover surface facility 64 that is separate from the intervention surface facility 58. The umbilical 36 is routed from workover surface facility 64 down through the open sea water to electro-hydraulic control system 42. Power and/or signal communication for subsea installation 22 is directed from surface facility 58 via signal carrier 28. However, the hydraulic fluid and equipment to handle the supply of hydraulic fluid for actuating devices 54 of subsea installation 22 is supplied from a separate system, such as the client supplied workover control system 34. This approach greatly simplifies the equipment required on surface intervention vessel 60, or other surface intervention facility, while improving the efficiency of the intervention operation.
As described, system 20 enables a methodology which simplifies intervention related operations on subsea wells by utilizing an outside source for pressurized hydraulic fluid to control the subsea installation components, e.g. subsea test trees, horizontal tubing hanger running tools, and many types of hydraulically controlled downhole equipment. The types of hydraulically actuated devices within the subsea installation and the actual components of the subsea installation may vary from one well operation to another. Additionally, many types of electro-hydraulic control systems may be utilized to direct hydraulic fluid to the appropriate hydraulic devices associated with the subsea installation.
The surface intervention vessel 60, or other surface intervention facility, can be designed to accommodate a variety of subsea intervention operations and other well related operations. Many types of equipment, including many types of risers and other types of tubing can be used in cooperation with a variety of permanent and temporary subsea equipment. In many of these operations, the outsourced supply of hydraulic fluid may be obtained from various workover control systems through many types of umbilicals. Regardless, the outsourced supply of hydraulic fluid for actuating components within the subsea equipment greatly increases the efficiency of the subsea operation.
Although only a few embodiments of the present invention have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this invention. Accordingly, such modifications are intended to be included within the scope of this invention as defined in the claims.
