Wireline formation testing for low permeability formations utilizing pressure transients
US5602334A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 17, 1994 |
| Grant date | Feb 11, 1997 |
| Priority date | — |
| Expiry date | Jun 17, 2014 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B49/008
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An improved formation testing method for measuring initial sandface pressure and formation permeability in tight zone formations exhibiting formation permeabilities on the order of 1.0-0.001 millidarcies based on pressure transients which occur shortly after the tester enters its pressure buildup cycle and substantially before reaching final buildup pressure. The method makes an estimate of formation permeability based on fluid decompression transients which occur in the formation tester flowlines which occur shortly after the tester begins its buildup cycle. The method further estimates initial sandface pressure based on the change in pressure over time shortly after beginning the buildup phase. The method of the present invention thereby permits accurate estimates of formation permeability and initial sandface pressure to be made relatively early in the buildup cycle, thus substantially reducing the time required to make the pressure and permeability measurements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.