Method and apparatus for correcting MWD porosity measurement
US5357797A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1993 |
| Grant date | Oct 25, 1994 |
| Priority date | — |
| Expiry date | Sep 22, 2013 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/00
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A porosity measuring MWD system utilizing a source and two detectors is set forth. The source and two detectors are preferably mounted in a stabilizer fin on a drill collar. A standoff measuring device is also included. Dependent on dynamically measured standoff, output pulses from the two detectors are input to storage counters; different counters are selected for different ranges of standoff. Porosity measurements are determined from the counts for variations in standoff measurements; this provides a near/far ratio for ranges of standoff; as the standoff range varies, the counts are directed to different counters. Near/far ratios are determined and represent the apparent porosity; a corrected value of porosity is then determined for each particular range of standoff.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.