Extended range, pulsed induction logging tool and method of use
US4849699A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 1987 |
| Grant date | Jul 18, 1989 |
| Priority date | — |
| Expiry date | Jun 8, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/28
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In accordance with the present invention, a pulsed induction logging system is provided which includes a logging sonde for traversing a borehole and having downhole microprocessor/controller circuitry in operative contact with a separate host computer/controller at the earth's surface. The host computer/controller and two downhole microprocessor/controllers constitute a network of digital computers and generate a digital pulsed logging code for periodically permitting a radiation coil to be driven by an oscillating current having high peak power. A powerful primary pulse of electromagnetic (EM) energy is periodically generated for irradiating the adjacent formation for induction logging purposes. The sonde also includes an antenna array for detecting secondary induced fields in the formation around the borehole. The array preferably includes a series of grouped, paired coils axially spaced along the borehole. Each group of paired coils independently detects the secondary field. Thereafter each detected signal per group of paired coils, is digitized, reformatted and transmitted to the host computer/controller at the earth's surface. The serially transmitted digital data is highly ac…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.