Method and system for formation evaluation
AssigneeCgg Services SAS
InventorStefan CALVERT
Life of this patent
Estimating the term…
Abstract
Formation evaluation methods and apparatuses use a COMET technique to cross-calibrate the total porosity and effective porosity approaches using logging tool measurements. The COMET technique minimizes the difference between total water saturation value and effective water saturation value assuming that non-conductive pore volume calculated using total porosity and using effective porosity is the same.
Claims20
A method of formation evaluation, comprising:
- evaluating conductivity, total shale porosity, effective porosity and total porosity based on logging tool measurements corresponding to same invaded formation volume;
- calculating a total water saturation value and an effective water saturation value using the conductivity, the total shale porosity, the effective porosity and the total porosity so that to have a same non-conductive pore volume result based on the total porosity and based on an effective porosity;
- and
- adjusting a value of dry clay density based on a difference between the total water saturation value and the effective water saturation value.
A formation evaluation apparatus comprising:
- an interface configured to receive logging tool measurements;
- and
- a data processing unit connected to the interface and configured:
- to evaluate conductivity, total shale porosity and total porosity based on the logging tool measurements corresponding to same invaded formation volume;
- to a total water saturation value and an effective water saturation value using dual water method, the conductivity, the total shale porosity and the total porosity so that to have a same non-conductive pore volume result based on total porosity and based on an effective porosity;
- and
- to adjust a value of dry clay density based on a difference between the total water saturation value and the effective water saturation value.
A computer readable recording medium non-transitorily storing executable codes that when executed by a computer make the computer perform a method of formation evaluation comprising:
- evaluating conductivity, total shale porosity and total porosity based on logging tool measurements corresponding to same invaded formation volume;
- calculating a total water saturation value and an effective water saturation value using the conductivity, the total shale porosity, the effective porosity and the total porosity so that to have a same non-conductive pore volume result based on total porosity and based on effective porosity;
- and
- adjusting a value of dry clay density based on a difference between the total water saturation value and the effective water saturation value.
Dependencies are inferred from the claim text.