Well control means
A controller for a well facility has at least one electronic control module (20) and at least one power switching module (21, 22). The power switching module may provide either a wholly hydraulic or wholly electrical output. The distributed electronic and power switching controls facilitate their removal and replacement by a remote operating vehicle. The modules are preferably housed on a subsea well tree (31).
This application claims the benefit of United Kingdom Patent Application No. 0319622.7, filed on Aug. 21, 2003, which hereby is incorporated by reference in its entirety.
TECHNICAL FIELD OF THE INVENTIONThis invention concerns the control of well facilities, for example underwater hydrocarbon extraction wells.
BACKGROUND OF THE INVENTIONA subsea well is conventionally controlled by equipment mounted on a structure known as a tree, which is typically located on or below the sea bed above the well bore. The tree houses a subsea control system, normally within a subsea control module (SCM) which comprises a subsea electronic module (SEM) and a hydraulic control module (HCM). The SCM is normally fed by an umbilical line from a surface station, e.g. from a surface platform, with electric power, control signals and hydraulic power. The control signals are processed by the SEM which then controls electrically operated, hydraulic directional control valves (DCV's) in the HCM, which in turn operate the multiplicity of hydraulic devices such as actuators, controlling the well.
The subsea control system is centralised within the tree, as illustrated diagrammatically in
A prior art attempt to decentralise the control system is described in GB 2 264 737 (ECA). Here the concept is to combine a limited electronic and hydraulic function within a small and light module, as schematically illustrated in
However, such prior systems have the major disadvantage of a substantially increased number of interface connections, both electrical and hydraulic, resulting in a reduction of the system reliability and availability. Furthermore, although failed individual control units are light enough to be within the handling capability of, and can be recovered by an ROV, it is time consuming to recover and replace the multiplicity of such units often required to clear a fault.
Various subsea well control systems are also described in U.S. Pat. No. 6,216,784, U.S. Pat. No. 4,120,362, US 2002/011286 A1, U.S. Pat No. 4,174,000, U.S. Pat. No. 4,378,848, U.S. Pat No. 4,497,369, U.S. Pat. No. 6,644,410, U.S. Pat No. 6,102,124, GB 2 194 980, EP 0 545 551, EP 0 627 544 and FR 2 574 849.
U.S. Pat No. 5,249,140, EP 0 247 335, EP 0 240 965 and EP 0 272 397 disclose distributed electro-hydraulic control systems.
SUMMARY OF THE INVENTIONThe present invention enables decentralisation of a well control system in new configurations whilst maintaining system availability.
In accordance with a first aspect of the present invention there is provided control means for a well facility, comprising an electronic control module and a power switching module, said electronic control module being configured to provide a wholly electronic output and said power switching module being configured to provide a power switching output using said electronic output.
The power switching module may provide either wholly hydraulic or wholly electrical output.
The electronic control module and the power switching module could be arranged to be removably mounted on a well tree.
Preferably, jumpers are used for carrying control signals from said electronic control module to said power switching module.
The control means may further comprise an umbilical termination unit. This may be arranged to be removably mounted on the well tree. A jumper may be used for connection between the electronic control module and the umbilical termination unit. A hydraulic feed for feeding hydraulic power from the umbilical termination unit to a hydraulic power switching module (or an electrical feed to an electrical power switching module) may also be provided.
Preferably, at least one of the electronic control module, the power switching module, the umbilical termination unit, the hydraulic feed, the electrical feed or the jumpers is adapted for removal and fitting by a remotely operated vehicle.
A plurality of power switching modules may be provided, each connected to said control module. At least one of them could produce wholly hydraulic output and at least one of them could produce wholly electrical output.
In accordance with a second aspect of the present invention, there is provided a well tree comprising the above control means.
In accordance with a third aspect of the present invention there is provided a well facility comprising the above control means.
In accordance with a fourth aspect of the present invention, there is provided a method of controlling well operations using an electronic control module to produce a wholly electronic output, which output controls a power switching module to produce a power switching output.
The electronic control module may receive control signals from a remote station, preferably via an umbilical termination unit.
BRIEF DESCRIPTION OF THE DRAWINGSThe invention will now be described by way of example with reference to the following figures, in which:
Referring firstly to
The lightweight well tree 31 is attached to the production tubing 32. Umbilical 25 carries hydraulic power, electrical power and control signals from a surface platform to the UTA 26. The UTA 26 is housed in a receptacle, facilitating its removal and replacement by an ROV. Electric power and control signals are fed to the SEM 20 via jumper 27. The tree 31 also functions as a hydraulic manifold which is fed from a tree hydraulic distribution unit 29, to connect hydraulic fluid to the hydraulic modules 21 and 22 and to provide outputs from the hydraulic modules to hydraulic operated devices such as actuators (not shown). The UTA 26 is connected by a hydraulic feed 28 to the tree hydraulic distribution unit 29.
The SEM 20 is located in a receptacle 33 attached to the tree 31, and is fitted with a handle 34 so that the module 20 can be removed from the receptacle 33 by an ROV. Jumpers 23 and 24 connect control signals from the SEM 20 to the hydraulic modules 21 and 22. All three jumpers 27, 23 and 24, as well as hydraulic feed 28 are designed to be removable and replaceable by an ROV. The hydraulic modules 21 and 22 are secured to the tree 31 by a locking screw arrangement, for example arrangements 35 and 36, such that an ROV can engage with the arrangement and detach each module from the manifold. The process of detaching the module causes the hydraulic feeds at both the manifold and the module to be automatically sealed. Likewise, replacement of the module by an ROV re-opens the feeds.
A major advantage of the ROV replaceable hydraulic modules is that they can be made truly standard so that the specific requirement of each well can be accommodated by fitting further hydraulic modules to other faces of the tree manifold, the number fitted being dependent on the complexity of the well. This not only saves the operator costs in that he does not have to fit a subsea control system which of itself provides all electrical and hydraulic functions to a low-complexity well, but also reduces hardware delivery time as “standard” units can be held in stock by the supplier. Each hydraulic module, being small and light, has a limited function capability. Typically each module contains seven DCV's along with hydraulic fluid supply filtration and pressure transducers. A further advantage is that variants can be provided of the standard, with lower component populations to further reduce costs.
During installation and workover, it is necessary to exercise the well operating devices such as valves and chokes before the umbilical is installed. Another advantage of the inventive system is that hydraulic power and electrical control can be connected to the tree via temporary workover “mini-umbilicals” connected to the SEM 20 and the tree distribution unit 29 during these non-production phases.
Although the invention has been described with reference to the embodiments above, there are many other modifications and alternatives possible within the scope of the claims. For example, the modules could be mounted on other than a well tree (for example on a subsea manifold, subsea template or subsea pipeline structure); there could be other electronic modules other than the electronic control module (for example for controlling or monitoring various downhole functions); and the invention may be applied other than in an underwater well facility; and at least one of the hydraulic power switching modules could be instead an electrical power switching module producing wholly electrical output and ROV replaceable.
Claims
1. A controller for a well facility, comprising an electronic control module and a power switching module, said electronic control module being configured to provide a wholly electronic output and said power switching module being configured to provide a power switching output using said electronic output.
2. The controller according to claim 1, wherein said power switching module produces wholly hydraulic output.
3. The controller according to claim 1, wherein said power switching module produces wholly electrical output.
4. The controller according to claim 1, wherein said electronic control module and said power switching module are arranged to be removably mounted on a well tree.
5. The controller according to claim 1, comprising a jumper for carrying control signals from said electronic control module to said power switching module.
6. The controller according to claim 1, further comprising an umbilical termination unit.
7. The controller according to claim 6, wherein said electronic control module and said power switching module are arranged to be removably mounted on a well tree and wherein said umbilical termination unit is arranged to be removably mounted on said well tree.
8. The controller according to claim 6, comprising a jumper for connection between said electronic control module and said umbilical termination unit.
9. The controller according to claim 6, wherein said power switching module produces wholly hydraulic output, the control means further comprising a hydraulic feed for feeding hydraulic power from the umbilical termination unit to the power switching module.
10. The controller according to claim 1, wherein at least one of said electronic control module, said power switching module, said umbilical termination unit, said hydraulic feed and said jumpers is adapted for removal and fitting by a remotely operated vehicle.
11. The controller according to claim 1, comprising a plurality of such power switching modules, each connected to said control module.
12. The controller according to claim 11, wherein at least one of said power switching modules produces wholly electrical output and at least one produces wholly hydraulic output.
13. A well tree comprising the controller according to claim 1.
14. A well facility comprising the controller according to claim 1.
15. A method of controlling well operations using an electronic control module to produce a wholly electronic output, which output controls a power switching module to produce a power switching output.
16. The method according to claim 15, wherein the electronic control module receives control signals from a remote station.
17. The method according to claim 16, wherein the control signals are received at the electronic control module via an umbilical termination unit.
Type: Application
Filed: Aug 20, 2004
Publication Date: Feb 24, 2005
Inventors: Philip Howe (Winscombe), Christopher King (Stoud)
Application Number: 10/923,630