Logging system for measuring dielectric properties of fluids in a cased well using multiple mini-wave guides
US5453693A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 1, 1993 |
| Grant date | Sep 26, 1995 |
| Priority date | — |
| Expiry date | Oct 1, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02A90/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An improved system for measuring dielectric properties of fluids in an oil well, utilizing the well casing as a waveguide for certain electromagnetic signals. A production logging tool in accordance with the invention includes a cylindrical mandrel sheathed by a housing. Transmitting and receiving coils are contained in annular grooves defined in the mandrel. In operation, the tool is suspended by a wireline logging cable within the casing of a producing well. The transmitting coils generate magnetic fields and azimuthal electric fields, which induce voltages in the receiving coils. These voltages are affected by the dielectric properties of fluids in the casing, and the voltages may be interpreted to determine dielectric properties such as water resistivity, dielectric permittivity, water hold-up, water cut, and water salinity. Due to specifically sized longitudinal mini-waveguides defined in annular regions about the circumference of the housing, the magnetic and azimuthal electric fields resulting from the transmitting coil may be sensed by the receiving coils, but the voltage-induced electric fields created by the transmitting coil are prevented from interfering with the receiv…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.