Methods to detect formation pressure
US6923052B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 2002 |
| Grant date | Aug 2, 2005 |
| Priority date | — |
| Expiry date | Oct 18, 2022 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B49/008
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Methods for estimating formation pressure from data taken during the drawdown cycle are presented. In one aspect, a method of determining a formation pressure during drawdown of a formation comprises sampling fluid from a formation using a downhole tool having a sample volume and a fluid sampling device. At least one time dependent parameter of interest related to the fluid is determined during the drawdown. The at least one time dependent parameter is analyzed using a plurality of calculation techniques to determine the formation pressure. The techniques include (i) a first pressure derivative technique; (ii) a second pressure derivative technique; (iii) a formation rate analysis technique; (iv) a dp/dt-ratio technique; and (v) a stepwise drawdown technique.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.