Nuclear magnetic resonance well logging to determine gas-filled porosity and oil-filled porosity of earth formations without a constant static magnetic field gradient
US6097184A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 31, 1997 |
| Grant date | Aug 1, 2000 |
| Priority date | — |
| Expiry date | Dec 31, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N24/081
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A technique is disclosed for determining the gas-filled porosity and oil-filled porosity in a region of investigation of earth formations surrounding a borehole including the following steps: (a) providing a logging device that is moveable through the borehole; (b) generating, from the logging device, a static magnetic field in the region of investigation of the formations, the static field having a magnetic field gradient that is not constant in the region of investigation; (c) determining the gradient distribution of the static magnetic field in the region of investigation, and determining a first function of the gradient distribution and the diffusion coefficient of oil, and a second function of the gradient distribution and the diffusion coefficient of gas; (d) generating a first sequence of magnetic field pulses in the region of investigation of the formations using a first wait time, and detecting a first sequence of nuclear magnetic resonance spin echoes from the formations; (e) generating a second sequence of magnetic field pulses in the region of investigation of the formations using a second wait time, and detecting a second sequence of nuclear magnetic resonance spin ech…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.