Abstract: A fluid sensor has a core defining a fluid flow path and a cavity member located externally of the core. The cavity member includes an electrically-conductive composite material including a matrix and one or more reinforcing elements embedded within the matrix. The cavity member is configured so as to provide confinement for an electromagnetic field and the core is configured so as to permit transmission therethrough of electromagnetic radiation at a frequency of the electromagnetic field. The electromagnetic field may be a radiofrequency (RF) electromagnetic field. The fluid sensor can be used in the measurement of the composition and/or flow characteristics of fluid in the fluid flow path.

Abstract: A method for use in measuring a composition of a multiphase fluid which includes flowing a multiphase fluid through a fluid flow path defined by a wall of a fluid conduit is disclosed. The wall includes an electrically non-conductive material. The method includes establishing an electromagnetic field which extends through the electrically non-conductive material of the wall of the fluid conduit into the fluid and measuring a property of the electromagnetic field over a measurement time period. The method also includes transmitting additional energy through the fluid over the measurement time period independently of the electromagnetic field and measuring the additional energy transmitted through the fluid over the measurement time period. The method may be used to unambiguously determine a composition of a multiphase fluid which has different components.

Abstract: An apparatus for measuring a composition of a fluid has a fluid conduit with a wall defining a fluid flow path, a transmitting antenna, a receiving antenna, and an electrically conductive waveguide member for electromagnetic coupling with the transmitting antenna and the receiving antenna and for guiding an electromagnetic field from the transmitting antenna to the receiving antenna along a waveguide path. The waveguide member is separated from the fluid flow path by an electrically insulating inner region of the wall. The waveguide member defines an opening disposed towards the fluid flow path to permit a portion of the electromagnetic field to extend through the opening and the inner region of the wall into the fluid flow path.

Abstract: A fluid sensor (10) comprises a base member (20) defining a fluid flow path (21), a cavity filler member (26) located externally of the base member (20), and a cavity member (30) located externally of the base member (20) and the cavity filler member (26). The cavity member (30) is configured so as to provide confinement for an electromagnetic field. The base member (20) and the cavity filler member (26) are both configured so as to permit transmission of electromagnetic radiation at a frequency of the electromagnetic field therethrough. The electromagnetic field may be a radio frequency (RF) electromagnetic field. The base member (20) and/or the cavity member (30) may define an outer cavity region externally of the base member (20). The cavity filler member (26) may completely or partially fill the outer cavity region. The fluid sensor (10) may be used in the measurement of the composition and/or flow characteristics of a fluid in the fluid flow path (21).

Abstract: A fluid sensor includes a core defining a fluid flow path, a confinement member located externally of the core, and a patch antenna located between the fluid flow path and the confinement member. The confinement member is configured to confine an electromagnetic field which extends into the fluid flow path. The patch antenna is configured to couple an electrical signal to and/or from the electromagnetic field. The fluid sensor may be configured for measuring the composition and/or flow rate of a fluid and, in particular but not exclusively, for measuring the composition and/or flow rate of mixtures of oil, water and gas.

Abstract: A fluid sensor (10) comprises a core (27) defining a fluid flow path (21) and a cavity member (30) located externally of the core. The cavity member (30) comprises an electrically-conductive composite material including a matrix and one or more reinforcing elements embedded within the matrix. The cavity member (30) is configured so as to provide confinement for an electromagnetic field and the core (27) is configured so as to permit transmission therethrough of electromagnetic radiation at a frequency of the electromagnetic field. The electromagnetic field may be a radiofrequency (RF) electromagnetic field. The fluid sensor (10) may be used in the measurement of the composition and/or flow characteristics of fluid in the fluid flow path (21).

Abstract: A fluid sensor comprises a fluid conduit having a wall defining a fluid flow path and an acoustic transducer located externally of the fluid flow path. The wall of the fluid conduit comprises a composite region between the acoustic transducer and the fluid flow path, the composite region comprising a composite material including a polymer matrix material and one or more reinforcing elements embedded within the polymer matrix material. Such a fluid sensor may be used for sensing a property of a fluid and, in particular though not exclusively for sensing a property of a fluid produced from or injected into an oil or gas well.

Abstract: A fluid sensor comprises a fluid conduit having a wall defining a fluid flow path and an acoustic transducer located externally of the fluid flow path. The wall of the fluid conduit comprises a composite region between the acoustic transducer and the fluid flow path, the composite region comprising a composite material including a polymer matrix material and one or more reinforcing elements embedded within the polymer matrix material. Such a fluid sensor may be used for sensing a property of a fluid and, in particular though not exclusively for sensing a property of a fluid produced from or injected into an oil or gas well.