Silixa Limited

Chevron U.s.a. Inc.

Dmitry Strusevich

Mahmoud Farhadiroushan

Tom Richard Parker

Sergey Shatalin

Daniel Finfer

Veronique Mahue

Embodiments of the present invention provide a cable for optical fiber sensing applications formed from fiber wound around a cable core. A protective layer is then preferably placed over the top of the wound fiber, to protect the fiber, and to help keep it in place on the cable core. The cable core is preferably of a diameter to allow bend-insensitive fiber to be wound thereon with low bending losses. The effect of winding the fiber onto the cable core means that the longitudinal sensing resolution of the resulting cable is higher than simple straight fiber, when the cable is used with an optical fiber sensing system such as a DAS or DTS system. The achieved resolution for the resulting cable is a function of the fiber winding diameter and pitch, with a larger diameter and reduced winding pitch giving a higher longitudinal sensing resolution.

Optical fiber cable

Embodiments of the present invention address aliasing problems by providing a plurality of discrete acoustic sensors along a cable whereby acoustic signals may be measured in situations where the fiber optic cable has not been secured to a structure or area by a series of clamps. Acoustic sampling points are achieved by selectively enhancing the acoustic coupling between the outer layer and the at least one optical fiber arrangement, such that acoustic energy may be transmitted selectively from the outer layer to the at least one optical fiber arrangement. The resulting regions of acoustic coupling along the cable allow the optical fiber to detect acoustic signals. Regions between the outer layer and the at least one optical fiber arrangement that contain material which is acoustically insulating further this enhancement since acoustic waves are unable to travel through such mediums, or at least travel through such mediums at a reduced rate.

Non-isotropic acoustic cable

Embodiments of the present invention address aliasing problems by providing a plurality of discrete acoustic sensors along a cable whereby acoustic signals may be measured in situations where the fiber optic cable has not been secured to a structure or area by a series of clamps, as described in the prior art. Acoustic sampling points are achieved by selectively enhancing the acoustic coupling between the outer layer and the at least one optical fiber arrangement, such that acoustic energy may be transmitted selectively from the outer layer to the at least one optical fiber arrangement. The resulting regions of acoustic coupling along the cable allow the optical fiber to detect acoustic signals. Regions between the outer layer and the at least one optical fiber arrangement that contain material which is acoustically insulating further this enhancement since acoustic waves are unable to travel through such mediums, or at least travel through such mediums at a reduced rate.

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Elstree, United Kingdom

Dmitry Strusevich