Methods for evaluating formations using NMR and other logs
US6032101A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 8, 1998 |
| Grant date | Feb 29, 2000 |
| Priority date | — |
| Expiry date | Apr 8, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02A90/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods that allow in-situ calculations of critical petrophysical parameters including, but not limited to, .phi..sub.t, S.sub.xot, Q.sub.v, F, and R.sub.w are provided. Also, NMR clay bound water may be used to estimate a continuous Q.sub.v. In combination with other resistivity logs, such as SP, R.sub.xo and R.sub.deep, R.sub.w can be determined. With the exception of the saturation exponent n, all Archie parameters and other computational equivalents are continuously determined directly from well logs. The methods therefore allow S.sub.w to be determined more accurately, which leads to improved estimation of hydrocarbon reserves. The method is extended to complex lithology with additional tools. In complex lithology, permeability estimation is also improved using a method that estimates bound fluid volume. Also, an uncertainty analysis of the gas-corrected parameters is also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.