Abstract: Method and apparatus determining the water saturation of a petroleum reservoir earth formation include transmitting electromagnetic energy in the earth formation from within a borehole traversing the earth formation and at least two frequencies within a preferred range of frequencies. The electromagnetic energy is received at two locations from the earth formation and within the borehole. The water saturation of the earth formation is derived from the received electromagnetic energy.

Abstract: An oil-water monitor includes a test cell having a production stream passing through it, thereby allowing the dielectric properties of the production stream to be monitored. An analyzer connected to the measuring cell provides an indication of the water content of the production stream in accordance with the dielectric properties of the production stream.

Abstract: A monitor which is capable of measuring accurately the water content in percent by volume of an oil and brine mixture, where the water content is 80% or more, includes a housing which is adapted to be connected to a pipe through which the oil and brine mixture is flowing so that the oil and brine mixture flows through a portion of the housing. A sensor is mounted within the housing so that the sensor is suspended in the flowing oil and brine mixture. The sensor provides a signal corresponding to the percent by volume of water in the oil and brine mixture, even when percent by volume of water is 80% or more, in response to an excitation voltage from a source. Indicating apparatus provides an indication of the percent by volume of the water in the oil and brine mixture in accordance with the signal from the sensor.