摘要 |
In apparatus for controlling a fluid production well, a control device D, such as a choke, located downhole is operable selectively by first and second drive means ( 2,3 ). First and second power supply means and first and second control channels (ChA, ChB) for control signals are provided for the first and second drive means, the arrangement being such that if one of the power supplies fails, the respective drive means is operable via the other power supply. First and second means (DEM 1 A, DEM 1 B) for routing control signals from the first and second channels respectively to the first and second drive means are provided, the routing means being interconnected so that, in the event of a fault, control signals from the second channel are routed via the first routing means to the second drive means and/or control signals from the first channel are routed via the second routing means to the first drive means.
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