초록 ▼

A method and apparatus for determining the interface between two materials having different dielectric properties, especially in determining the thickness of a hydrocarbon layer on ground water, is disclosed. The apparatus consists of an air-filled, cased surveillance well in which a logging tool is

A method and apparatus for determining the interface between two materials having different dielectric properties, especially in determining the thickness of a hydrocarbon layer on ground water, is disclosed. The apparatus consists of an air-filled, cased surveillance well in which a logging tool is raised and lowered. The logging tool contains an electromagnetic receiving antenna and two transmitting antennas located above and below the receiving antenna. A first wave and a second wave are transmitted from the transmitting antennas. The first and second waves are offset 180°to produce “sum”and “delta”signals using a ½°hybrid. Alternatively, a single wave can be transmitted from a central transmitting antenna to receiving antennas located above and below the transmitting antenna. The received signals are then phase shifted 180°using a 180°hybrid to produce sum and delta signals. As the tool is raised and lowered in the well bore, changes in the sum and delta signals will be observed when an interface is passed. A logging tool for use in petroleum production and exploration wells is also disclosed.

대표청구항 ▼

A method of determining the location of an interface of dielectrically different material comprising the steps of: (a) transmitting electromagnetic radiation from a first transmitting antenna and a second transmitting antenna in a wellbore, the radiation from the first transmitting antenna and the s

A method of determining the location of an interface of dielectrically different material comprising the steps of: (a) transmitting electromagnetic radiation from a first transmitting antenna and a second transmitting antenna in a wellbore, the radiation from the first transmitting antenna and the second transmitting antenna having a common phase and amplitude, said first transmitting antenna located above said second transmitting antenna; (b) receiving a sum signal resultant from the step (a) at a receiving antenna located between said first transmitting antenna and said second transmitting antenna; (c) transmitting electromagnetic radiation from the first transmitting and the second transmitting antennas, the transmitted radiation from the first and second antennas having a common amplitude and phases differing by 180?; (d) receiving a delta signal resultant from step (c) at said receiving antenna; (e) moving said antennas across the interface; and (f) monitoring said sum and said delta signals for changes whereby the interface can be detected.