Multiplexed electrohydraulic control system for an underwater production installation

Abstract: This invention concerns a multiplexed electrohydraulic kind of control system consisting of ten undersea control modules, (24), arranged and installed one for each local Xmas tree (14) and satellite Xmas module (18). System links up with a stationary production system by means of two hydraulic umbilicals, (42), and one electric umbilical, (44), this latter through an electric distribution module, (26), while connection of jumper, (84) of undersea control module, (24), and to electric distribution module, (26) is done by means of a remotely controlled vehicle (R.O.V.), (30).

Description: Field of Invention This invention concerns a multiplexed electrohydraulic type of control system for use in an undersea production system which enables the valves of each undersea well to be individually controlled by digital electronic means operated by an operator at a computer at the stationary production unit. Background of the Invention A multiplexed electrohydraulic type of control system has to be provided with some kind of electric power supply and means of communication with the control and supervision station, through which to interface with the operator. The ideal way to avoid the use of an undersea umbilical with electric cables between the platform and the template would be to provide the undersea control module with its own power supply source and/or place, together with means to enable it to communicate directly with the platform through the undersea environment in which it lies. Furthermore, the need to develop various other kinds of technology connected with the idea is why it has not yet gained the degree of reliability and safety needed in the control of undersea production systems. Description of the Prior Art Within the present state of the art, multiplexed electrohydraulic control systems employ electric umbilicals to provide power and communication for undersea control modules. A big drawback to this has always been the need to have electric connectors in the undersea structures and/or equipment whenever two or more modules have to share one common electrical umbilical which generally makes it more difficult to carry out maintenance of the system whenever faults appear in stretches of equipment therein. An example of this would be a template manifold with control modules installed at the Xmas trees, where a mere faulty connector or electric cable within the manifold would mean that production at all wells would have to be stopped and the manifold would have to be brought to the surface for the repair of a single connector, or electric jumper, otherwise multiplexed control over the faulty well would be lost. Summary of the Invention This invention as defined by claim 1 provides a multiplexed electrohydraulic type of control system which consists of ten undersea control modules arranged and installed as one for each local Xmas tree and module of satellite tree. The system is linked up with a stationary production unit by means of two hydraulic umbilicals and one electric umbilical, the latter through an electric distribution module. In order to avoid the need to recover the manifold in the event of a fault in the jumper or electric connector therein, the connection between the jumper in the undersea control module and electric distribution module is achieved by means of an R. O. V (remotely operated vehicle). By allowing such connections to be made and unmade locally, at the template, the electric jumper can be within the template, which in the event of a fault can be remotely disconnected by the R. O. V., thus enabling a new jumper to be laid upon the template and connected at both its ends to the R. O. V., thus restoring the electrical connection. Brief Description of the Drawings The multiplexed electrohydraulic type of control system used for an undersea production system, as in this invention, will now be described in greater detail with the help of the drawings hereto. Figure 1 is a view of connection of a jumper to an undersea control module and to an electric distribution module by means of a remotely operated vehicle - R. O. V. Figure 2 is a flow chart of the undersea hydraulic arrangement. Figure 3 is a hydraulic flowchart of the connection of undersea control module to a local wet Xmas tree. figure 4 is a flowchart of hydraulic interfaces with local wet Xmas tree, top of wet tree, cover of wet Xmas tree, bed of undersea control module, and terminal for manifold connection. Figure 5 and 6 are flowcharts of hydraulic interfaces with satellites tree module and structure of flow line. Figure 7 is a hydraulic flowchart of control for satellite tree module and satellite wet Xmas tree. Figure 8 is a schematic diagram showing electric interfaces with local wet Xmas tree. Figure 9 is a shematic diagram showing electric interfaces with satellite tree module and structure of flow line. Figure 10 is a schematic diagram of electric distribution module. Figure 11 is a schematic diagram of an undersea electric distribution arrangement. Figure 11A is an enlarged detail of the electric distribution arrangement, taken from Figure 11. Figure 12 is a block diagram of preferred electronics for undersea control module. Detailed Description of the Invention The multiplexed electrohydraulic control system of this invention is used in an undersea production system of the kind described in EP-A-0480772, published after the priority date of the present application, which amongst other features operates at 600m depth of water; while template, 10, and manifold, 12, are separate structures and can be installed separately; manifold, 12, will have four headers: for production, gas-lift, production testing and injecting of water/secondary production; manifold, 12, has blocking valves worked only by a remotely controlled vehicle - R. O. V. For a local well, all production and control valves for the headers of the manifold 12, lie in their own Xmas tree (local MXM), 14; the interface of template-manifold with satellite well production and control lines will be by means of the flow lines structure (F.L.S), 16 (Fig. 9), of the satellite tree module (S. T. M), 18, of the respective well. S. T. M 16 is like an MXM 20, and may be installed and locked on to any of the ten openings of the template, 10, so as to enable the manifold, 12, to interface with a satellite well; horizontal connections to be used between manifold, 12, and each local MXM, 14, S. T. M. 18, terminals for hydraulic and electric umbilicals for export-lines, as well as flexible satellite M. X. M. For this invention the primary control system is to be multiplexed electrohydraulically, and there shall also be a secondary hydraulic system as standby for the first, while inductive type electric connectors are to be employed in transmitting all electric power and communications signals. The primary system consists of ten undersea control models (U. C. M. 's) 24, each installed at every local M. X. M. 14, and/or S. T. M. 18. Such modules 24 are fed hydraulically and electrically by distribution systems installed in the manifold. The hydraulic distribution system is connected to stationary production unit by two umbilicals coming straight from the manifold. For electric distribution there is a junction box, known as an electric distribution module (E. D. M.) 26, which links this kind of distribution and the electric umbilical to the stationary production unit. At the stationary production unit, in turn, the control and supervision stations are to be installed, hydraulic and electric supply units, panels for the secondary control system and for safety valves (S. C. S. S. V.), stationary production unit connection to umbilicals taking place by means of rapid connecting and disconnecting devices. Link up with the manifold will be done by two hydraulic and one electric umbilical. Each hydraulic umbilical will consist of: 1 pressure feed line to U. C. M.; 5 pressure lines for secondary control; and 5 pressure lines for S. C. S. S. V. For undersea hydraulic distribution each WXT, 20 or S. T. M. 18, will be given three control lines by means of its connection with manifold 12 that is a hydraulic feed line from its U. C. M., a line to work its secondary control, and a line to work its S.C.S.S.V. Each U. C. M. 24, will be connected by E. D. M. 26 by means of an electric cable 28 which will provide energy and communications signals. All electric cables will be installed in manifold 12 in such a way as to enable it to be connected to the E. D. M. 26, and to the respective U. C. M. 24 by means of an R. O. V. 30, without any help from divers. The great advantage of this system is that, in the event of any fault in the cable and/or its electrical connectors, the cable may be disconnected at both ends and replaced by another, which will be lowered and laid upon the manifold, 12; upon connecting up the new cable a connection is restored which would otherwise have been lost, or would at least have taken time and much expense to have been worked upon, while undersea electrical connections between umbilical and stationary production unit and each U. C. M. employ induction type connectors. U. C. M. 24 will be the device which, upon being given a suitable command from the control and supervision station will operate the corresponding valve. Likewise, regular scanning will take place to update undersea sensor figures. U. C. M. 24 should be a cylindrical container filled with dielectric fluid and should be provided with an outside pressure compensating device. Connection of control lines between U. C. M. 24 and its seat 32 takes place by means of individual hydraulic connectors for each line; electric connection for undersea transducers also taking place by means of seat 32 of U. C. M. 24. Such connectors should be of the conducting kind, with a device to keep their electrical contacts protected both during and after disconnecting. The electrical connection for the cable from E. D. M. 26, is of the induction kind. It will link up with U. C. M. 24 by means of a connector that can be manipulated by an R. O. V., and placed in the upper side of the U. C. M. All control and data collecting tasks undertaken by the U. C. M. will be managed by a set of smart electronic circuits, upon receiving orders from the surface, while such circuits will be installed in an airtight container filled with inert gas at atmospheric pressure. E. D. M. 26 will distribute the energy and communications signals from the stationary production unit (S. P. U. ) to all the undersea electrohydraulic control modules 24, and should be installed in a special part of manifold 12 suitable for horizontal connection with the electrical umbilical locked to template 10. The control and supervision station (C. S. S. ) will consist of a control panel 36, and will interface with undersea control modules 24, and a computer 38, and with a printer 40 for man-machine interface. The secondary control mode enables the operator to keep a well in production controlled directly from the S. P. U. by means of a primary control override. Each local WXT, 14 and S. T. M. 18 are provided with a set of duties in whose control lines shuttle valves are installed one for each duty. Each well have its own secondary control line from the S. P. U. , which line is linked together will all the shuttle valves of this local WXT, 14, or S. T. M. 18, so that its pressurization will keep open all duties with which it is associated. In view of the foregoing the invention aims at a multiplexed electrohydraulic type of control system to be used in an undersea production system, said control system consisting of ten modules of undersea control (U. C. M. ) 24, arranged and installed one for every local wet Xmas tree 14 and satellite tree module (S. T. M. ) (18), which will link up with the stationary production unit by means of hydraulic umbilicals (42) and electric umbilicals (44), the latter through an electric distribution module (E. D. M. ) 26, connection of an electric jumper (84) to said undersea control module (U. C. M. ) (24), and to said electric distribution module (E. D. M. ) (26) being effected by means of a remotely operated vehicle (R. O. V. ) (30). The primary control system is of the multiplexed electrohydraulic kind and also includes a secondary hydraulic system as standby for said primary system. The hydraulic distribution system is linked to the stationary production unit by hydraulic umbilicals (42) coming directly from manifold (12), and electrical distribution is provided with an electrical distribution module (E. D. M. ) (26) which links this distribution and the electrical umbilical (44) to the stationary production unit. Each such hydraulic umbilical (42) consists of a pressure feed line for said undersea control module (U. C. M. ) (24), a pressure line for the secondary control, and pressure lines for safety valves. At the undersea hydraulic distribution means, every wet Xmas tree (WXT) (20) or satellite tree module (S. T. M. ) (18), receives control lines by means of its connection with the manifold (12) one of which lines is for hydraulic feed of its undersea control module (U. C. M. ) (24), one for working its secondary control, and one to work its safety valve. All electrical cables, (28), are installed in the manifold (12), connection of the electric cable (28) to the electric distribution module (E. D. M. ) (26) and to the respective undersea control module (U. C. M. ) (24), being achieved by means of a remotely operated vehicle (R. O. V. ) (30). The electrical connection of electrical cable (28) from electric distribution module (E. D. M.) (26) is of the induction kind, said electric cable (28) being linked to the undersea control module (U. C. M. ) (24) by means of a connector (34) that can be manipulated by a remotely-operated vehicle (ROV) (30), lying in the upper side part of said undersea control module (UCM) 24. A look at Figure 1 serves to show that the control system is linked up with the stationary production system by means of two hydraulic umbilicals 42 and one electric umbilical 44, the latter through an electric distribution module (EDM) 26. Connection at the undersea control module (UCM) 24, and at the electrical distribution module (EDM) 26 is effected by means of a remotely-operated vehicle (ROV) 30. Figure 2 is a flowchart of undersea hydraulic distribution of wells 46A-46J, showing terminals 48 to connect the umbilical to the manifold, connection 50 of the manifold 12 to WXT 20, and a maintenance panel 52 of hydraulic distribution to operating valves 54 for an ROV. Figure 3 shows a hydraulic flowchart of the connection 56 of undersea control module 24 with a local wet Xmas tree 14 with pressurestats 58. Figure 4 shows a flowchart of hydraulic interfaces of tree-cap 60, top of WXT 62, local WXT 14, seat 64 of UCM 24, and connection terminal of manifold 66. Figures 5 and 6 are flowcharts of hydraulic interfaces with satellite tree module 18, and the flow line structure 16. Figure 5 shows the connecting plate 68 to the satellite tree module 18, and the terminal 70 for connection with the umbilical and satellite WXT, and Figure 6 shows the top of STM 72, the seat of UCM 62, and the terminal to connect manifold 48 and a connecting plate 72 to the FLS 16. Figure 7 shows a hydraulic flowchart of STM 18 and satellite WXT, connection with STM 76 being also shown. As can be seen from Figure 8, which is a schematic diagram of the electrical interfaces of local WXT 14 with UCM 24, the container 78 is shown with electronic circuits including electric power induction connectors 80, signal induction electric connectors 82, and electric jumper 84, along with connection, to be made by ROV, to the connector seat of UCM 32 using conduction type unthreaded electric coupling connectors 86. Figure 9 is a schematic diagram of electric interfaces of STM 18 with FLS 16, and shows horizontal connection hubs 88, seat structure 90 for flow line and a control umbilical of satellite WXT 22, threaded conductive electric connector 92, and electric cable 94 of the control umbilical of the satellite WXT 22. Also, as can be seen from Figures 8 and 9, each local WXT 14, and STM 18 will be provided with two pressure transducers 96, and two external sensors of the positions of choke valves 98, while local WXT 14 and satellite WXT 22 may also be provided with a transducer 100 for down-the-hole pressure and temperature (DPTT). Figure 10 is a schematic diagram of the electric distribution module 26 showing the umbilical 102 of a stationary production unit, hubs 104 induction electric connectors 80 for power, induction electric connectors 82 for signals, feed and distribution arrangement 106, with its protection circuits 108, and feed and distribution arrangement 110 for signals, with its protection circuits 112. Figures 11 and 11A are a schematic diagram of the undersea electric distribution assembly and an enlarged detail of EDM 26 taken from Figure 11, and show template 10, manifold 12, EDM 26, UCM's 24, and electrical umbilical 102 for VEP (Figure 11), hubs 88 for horizontal connection, power induction electrical connectors 80, signal induction electrical connectors 82, protection and distribution circuits 114, and electric jumper 84 for remote connection by ROV. Finally, Figure 12 is a block diagram of the preferred electronics for undersea control module 24, showing jumper 84 for the electric distribution module, feed induction connector 116, signal induction connector 118, power source 120, communications interface 122, microprocessor 124, interface driver 126 for a solenoid valve, interfaces 128 for SPDT switch, A/D converter and multiplexer 130, signal arranger, and interface 132 for DPTT, signal arranger and pressure transducer 134, and signal arranger and interface for sensor for choke position 136. It should be pointed out that though the whole of the control system description has been based on the undersea production system described in the EP-A-0480772 its main features as defined by the appended claims may be considered as those of other undersea production systems (template-manifold, manifold, wet Xmas trees).

Claims: A multiplexed electrohydraulic control assembly for use in an undersea production system, comprising a plurality of undersea control modules (24), each arranged and adapted to be installed alone for each local wet Xmas tree (14) and satellite tree module (18), wherein said control assembly is adapted to link up with a stationary production unit by means of hydraulic umbilicals (42) electric umbilicals (44), an electric distribution module (26), and electric cables (28) installed in a manifold (12); wherein said electric cables (28) are connected to said electric distribution module (26) and to said undersea control module (24) by means of electric connections (28) of the induction type including a connector (34) which can be manipulated by a remotely-controlled vehicle (30), said cables (28) constituting an electric jumper connection (84) between said undersea control module (24) and said electric distribution module (26). A multiplexed electrohydraulic control assembly according to claim 1, comprising a primary control means of the multiplexed electrohydraulic kind, and also including a secondary hydraulic means as standby for said primary system. A multiplexed electrohydraulic control assembly according to claim 1 or 2, wherein the hydraulic distribution means is connected to the stationary production unit by hydraulic umbilicals (42) coming straight from a manifold (12), and the electric distribution is provided with an electric distribution module (26) which links such distribution to the electrical umbilical (44) of the stationary production unit. A multiplexed electrohydraulic control assembly according to claim 1, 2 or 3, wherein each said hydraulic umbilical (42) consists of a pressure feed line for said undersea control module (24), a pressure line for secondary control, and pressure lines for safety valves. A multiplexed electrohydraulic control assembly according to any preceding claim, wherein at the undersea hydraulic distribution each wet Xmas tree (20) or satellite tree module (18) is provided with control lines by means of its connection to manifold (12), namely one line for hydraulic feed of its undersea control module (24), one line to drive its secondary control, and one line to drive its safety valve.

Inventors: COELHO EDUARDO JOSE DE JESUS, CONTI FABIO KERR PINHEIRO, EUPHEMIO MAURO LUIZ LOPES, FREITAS RICARDO MUNOZ, COELHO, EDUARDO JOSE DE JESUS, CONTI, FABIO KERR PINHEIRO, EUPHEMIO, MAURO LUIZ LOPES, FREITAS, RICARDO MUNOZ
Applicants: PETROLEO BRASILEIRO SA, PETROLEO BRASILEIRO S.A. - PETROBRAS
Application year: 1992
Main classification: E21B43
IPC codes: E21B33, E21B43