Abstract: An apparatus for sensing strain applied to a region of a hydrocarbon well comprises an optical fiber in communication with the region. The optical fiber is responsive to strain applied to the region and to a light signal transmitted through it, in order to produce a sensing light signal incorporating scattered light. A characteristic of the scattered light is indicative of the strain being applied to the region.

Abstract: It is desirable to be able to monitor the condition of a filter in a fluid flow system, for example a sandscreen 3,4 in a fluid well. The invention provides monitoring apparatus including an optical fibre 6 having a pressure sensor 7. Pressure is exerted on the sensor, by fluid flowing through the sandscreen, via ports 10 and 11. The pressure sensor is responsive to a light signal, and to the exerted pressure, to produce a sensing light signal indicative of a characteristic of the fluid flow, such as pressure differential or fluid velocity. This, in turn, is indicative of the condition of the sandscreen or filter.