Methods and apparatus for determining dielectric constant and resistivity with electromagnetic propagation measurements
AssigneesSchlumberger Technology Corporation, Saudi Arabian Oil Company
InventorsGong Li Wang, Dean M. Homan, Ping Zhang, Wael Abdallah, Shouxiang Ma
Life of this patent
Estimating the term…
Abstract
A method for estimating resistivity and dielectric constant values of a multi-layer subterranean formation acquiring electromagnetic propagation measurements of the subterranean formation and processing the measurements via inversion to compute the resistivity and dielectric constant values. A one-dimensional formation model is utilized including a plurality of formation layers in which each of the formation layers includes a resistivity value and a dielectric constant value.
Claims18
A method for estimating resistivity and dielectric constant values of a subterranean formation, the method comprising:
- acquiring electromagnetic propagation measurements of the subterranean formation;
- and
- processing the electromagnetic propagation measurements via inversion using a one-dimensional formation model including a plurality of formation layers to compute resistivity and dielectric constant values of each of the plurality of formation layers,
- wherein the electromagnetic propagation measurements are inverted via minimizing a cost function comprising a misfit term, an entropy term, and a smoothing term, and
- wherein the misfit term, the entropy term, and the smoothing term are each dependent on the resistivity and the dielectric constant values of each of the plurality of formation layers.
A system comprising:
- a downhole electromagnetic logging tool configured to make a plurality of electromagnetic propagation measurements of a subterranean formation;
- a processor;
- and
- memory storing instructions configured to be executed by the processor, the instructions comprising instructions to:
- receive the electromagnetic propagation measurements made by the downhole electromagnetic logging tool;
- and
- process the electromagnetic propagation measurements via inversion using a one-dimensional formation model including a plurality of formation layers to compute resistivity and dielectric constant values of each of the plurality of formation layers,
- wherein the electromagnetic propagation measurements are inverted via minimizing a cost function comprising a misfit term, an entropy term, and a smoothing term, and
- wherein the misfit term, the entropy term, and the smoothing term are each dependent on the conductivity and the dielectric constant vales of each of the plurality of formation layers.
An article of manufacture comprising tangible, non-transitory, machine-readable media comprising instructions that, when executed by a processor, cause the processor to:
- receive electromagnetic propagation measurements made by a downhole electromagnetic logging tool;
- and
- process the electromagnetic propagation measurements via inversion using a one-dimensional formation model including a plurality of formation layers to compute resistivity and dielectric constant values of each of the plurality of formation layers,
- wherein the electromagnetic propagation measurements are inverted via minimizing a discretized cost function comprising a misfit term, an entropy term, and a smoothing term, and
- wherein the misfit term, the entropy term, and the smoothing term are each dependent on the conductivity and the dielectric constant values of each of the plurality of formation layers.
Dependencies are inferred from the claim text.