Abstract: A system including a transmitter mounted inside a pressure bulkhead of a drill tool transmitting a light at a first wavelength is provided. The system includes a receiver mounted inside the pressure bulkhead to detect a second light at a second wavelength. The system also includes a wavelength multiplex unit positioned within the first pressure bulkhead for coupling the light at the first wavelength and the light at the second wavelength with an optical coupler. The optical coupler provides the light at the first wavelength to an external medium via a pressure resistant window and receives the light at the second wavelength from the external medium via the pressure resistant window. A method of using the above system to transmit and receive messages in a downhole optical link is also provided.
Abstract: Fluid flow measurement device and method. In one embodiment, a tool comprises a rotating arm with a sensor pad to measure fluid flow into or out of the casing wall. The arm maintains the sensor pad in close proximity to the casing inner wall. The tool diameter is variable to allow the tool to traverse variable diameter casings and pass obstacles. The sensor pad comprises flow channels to direct the flow of fluid by electromagnetic sensors configured to detect conductive fluid flow.
Abstract: A bi-directional fluid flow sensor is disclosed. The sensor comprises a turbine configured to rotate along an axis as a result of fluid flowing past the turbine substantially in the direction of the axis; a magnet mounted to the turbine and configured to rotate with the turbine; and a magnetic flux angle sensor provided adjacent to the turbine and configured to detect the relative flux angle of the magnet as it rotates. The bi-directional fluid flow sensor is sensitive and robust and may be used in a downhole well for example.
Abstract: A flow meter for measuring the velocity of surrounding fluid, comprising a rotatable member rotatably coupled to a shaft member, wherein the shaft member comprises a measuring electrical circuit comprising an AC power supply and a primary coil, the rotatable member comprising a passive non-permanent magnet marker responsive to a magnetic field, the arrangement being such that when the circuit is powered by the AC supply the coil generates a magnetic field and the marker is positioned on the rotatable member such that rotation of the rotatable member in response to fluid drag on the member causes the distance between the marker and the coil to oscillate, the marker interacting with the magnetic field at its closest approach to the coil, thereby to cause a measurable electrical response in the circuit.
Abstract: The invention relates to a borehole radar tool comprising, in a housing (2) a transmitting antenna and a receiving antenna both of which comprise, near the housing wall (2), a dipole antenna (8) and a reflector (10) opposite thereto. Also provided are an algorithm, method and apparatus for determining electromagnetic contrast information of a site into which electromagnetic fields (27) are emitted. Signals (29) generated by induction are intercepted and, using a back-projection algorithm including a suitable weighting factor, are converted into contrast information. The algorithm and/or method can be recorded in a computer program or on a data carrier. Also disclosed is a method of determining said weighting factor. The invention further provides a method and apparatus for subsurface surveys in which electromagnetic pulse signals are emitted.
December 30, 2002
Date of Patent:
March 30, 2004
T & A Survey B.V.
Michiel Sebastiaan van Oers, Koen Willem Anton van Dongen, Petrus Maria van den Berg, Jacob Tjeerd Fokkema, Robert van Ingen, Neil Vladimirovich Budko, Robert Frans Remis