Method of determining the permeability of sedimentary strata
US6140816A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 12, 1997 |
| Grant date | Oct 31, 2000 |
| Priority date | — |
| Expiry date | Dec 12, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V11/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A permeability estimator is constructed from the lambda parameter, .LAMBDA., which is the size of dynamically connected pores. For simple pore geometries at high permeabilities, .LAMBDA. should theoretically be proportional to the pore volume-to-surface area ratio. Further, at high permeabilities, the permeability is proportional to .LAMBDA..sup.2 /F where F is the formation factor. Core data are used to establish the proportionality constant. At permeabilities less than about 100 md, the estimated permeability is seen to overestimate the actual permeability by a factor related to the estimate. Thus, a corrected second estimate can be readily made and is shown to match measured permeabilities on a diverse set of sands and shaly sands with a correlation coefficient of 0.89 for log k. The estimate can also be made using NMR relaxation time data with a correlation coefficient of 0.92 for the same data set. The estimate can also be made from mineralogy data where each mineral is assumed to have a fairly constant specific surface area.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.