Oxygen activation method for quantitative water flow measurements within and behind well bore casing
US5461909A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 23, 1994 |
| Grant date | Oct 31, 1995 |
| Priority date | — |
| Expiry date | Sep 23, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/101
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for measuring the linear flow velocity, radial position, direction, and the flow rate of water flowing within and behind a well borehole casing. A logging tool containing a source of essentially monoenergetic 14 MeV neutrons and at least one gamma ray detector is positioned within the well borehole opposite the zone in which water flow measurements are desired. The neutron source is turned on thereby irradiating any flowing water and other areas in the vicinity of the well borehole with high energy neutrons. After a predetermined irradiation time, the neutron source is turned off. Following a quiescent period of several milliseconds to allow thermal capture gamma radiation to decay to a negligible level, the gamma ray detector is turned on and the count rate from the N-16 induced within the flowing water is recorded as a function of time. The linear flow velocity, the Full Width Half Maximum time period, and the total count are determined directly from the resulting count rate curve. The radial position and the flow rate are determined using the predetermined relationship between the Full Width Half Maximum time period, radial position, and linear flow velocity, and the pr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.