Patent ID: 7308165
Filing Date: 2007-12-11
Classification: G01L

Abstract:
1. An optical transducer for the simultaneous measurement of downhole pressure and temperature, said transducer being inserted in a system comprising a light emitter, an optical fiber containing Bragg gratings, the emitted light propagating along the core of said optical fiber until said light meets a Bragg grating able to reflect a portion of said light, wherein said transducer comprises a predominantly cylindrical body, including: a) a membrane designed for pressure measurement; b) at least one Bragg grating designed for pressure measurement attached to said elastic membrane; and c) at least one Bragg grating for temperature measurement; wherein said gratings are in the same optical fiber, and wherein said body has: a) a bore along a main axis coaxial with or parallel to a longitudinal axis thereof to allow the passage of said optical fiber therethrough so as to secure access to both ends of said optical fiber; b) two symmetry planes in order to facilitate installation and connection in series with other optical fiber transducers and sensors; c) a central access and respective stop, perpendicular to the main axis of said body, on an opposite side of said membrane with respect to said optical fiber, to allow the attachment of at least one Bragg grating to said membrane; and d) sealing means against the outer pressure, at the inlet and at the outlet of the bore, whereby the membrane conveys a strain that is proportional to the pressure and temperature conditions to which the transducer is exposed, the portion of non-reflected light by the Bragg gratings continuing along the remaining length of the optical fiber.