Method of measuring horizontal fluid flow in cased off subsurface formations with manganese compensation
US4137452A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 20, 1977 |
| Grant date | Jan 30, 1979 |
| Priority date | — |
| Expiry date | Jun 20, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F1/7042
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Fluid in permeable earth formations adjacent well casing is irradiated with neutrons to form radioactive tracer isotopes in the chemical elements comprising the fluid, typically sodium 24 in saline subsurface formation water, which decays by emission of gamma rays. By measuring the rate of decay of the radioactive isotope, a measure of horizontal fluid flow in the formation is obtained. Manganese, present in the steel well casing, has been found to also respond to the neutron irradiation by forming the isotope manganese 56 which emits gamma rays which interfere with the gamma radiation measurements of the trace element indicative of water flow. A method of measuring horizontal fluid flow while compensating for the presence of manganese 56 gamma rays is disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.