Borehole caliper derived from neutron porosity measurements
US6285026A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1999 |
| Grant date | Sep 4, 2001 |
| Priority date | — |
| Expiry date | Mar 30, 2019 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/085
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A system for measuring the size of a borehole penetrating an earth formation is disclosed. The system uses a neutron source and a least one neutron detector. The neutron detector responds primarily to the composite hydrogen content of material within the borehole and formation upon irradiation by the neutron source. A partition response function is used to delineate the portion of the detector response resulting from borehole and from the formation. Since the detector response from the borehole can be isolated using the partition function and the hydrogen content of the borehole fluid is generally known, the size of the borehole can be determined from borehole response portion of the composite detector response if combined with a neutron porosity measurement of the formation. The neutron porosity measurement can be obtained independently, or by combining the neutron detector response with the response of a second neutron detector at a different axial spacing from the neutron source. The system is applicable in both logging-while-drilling and wireline logging operations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.