Derivative ratio test of fluid sampling cleanup
US11193826B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 2019 |
| Grant date | Dec 7, 2021 |
| Priority date | — |
| Expiry date | Feb 18, 2040 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B49/0875
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method for performing a formation fluid test in a borehole penetrating a subsurface formation includes disposing a fluid tester in the borehole, extracting a sample of fluid from the subsurface formation using the fluid tester, and analyzing the sample using the fluid tester to provide test data for a process used to analyze the sample. The method also includes fitting an equation to the test data and calculating a ratio of a first derivative of the equation to a second derivative of the equation. The method further includes continuing to extract the sample from the subsurface formation in response to the ratio indicating a clean sample will be forthcoming and terminating the extracting of the sample from the subsurface formation in response to the ratio indicating a clean sample will not be forthcoming.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.