Method to estimate water saturation in electromagnetic measurements

Patent metadata

Field	Value
Publication number	US-10330618-B2
Application number	US-201615569094-A
Country	US
Kind code	B2
Filing date	Apr 29, 2016
Priority date	Apr 30, 2015
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

A method to estimate water saturation in electromagnetic measurements includes making an electromagnetic measurement and performing at least one of (a) creating an analytical forward model of the EM measurement, (b) creating a numerical finite difference forward model of the EM measurement, and (c) performing an inversion. The method also includes removing at least one petrophysically-adverse alteration of EM measurements in the frequency range from 1 Hz to 100 MHz. A petrophysically-adverse alteration is due to the presence of at least one of the following: pyrite, graphitic-precursors, magnetite, and other conductive minerals.

First claim

What is claimed is:

1. A method to estimate water saturation in electromagnetic (EM) measurements comprising:
making an EM measurement;
performing at least one of creating an analytical forward model of the EM measurement, creating a numerical finite difference forward model of the EM measurement, performing an inversion;
removing at least one petrophysically-adverse alteration of EM measurements in a frequency range from 1 Hz to 100 MHz; and
wherein the at least one petrophysically-adverse alteration is due to the presence of at least one of the following: pyrite, graphitic-precursors, magnetite, and other conductive minerals.

2. The method according to claim 1 , further comprising placing an arrangement of sensors into a wellbore environment for making the EM measurement.

3. The method according to claim 2 , wherein the EM measurement is made of at least one of disseminated conductive/non-conductive vugs, veins, fractures, lamentations, and thin beds.

4. The method according to claim 1 , wherein a joint interpretation is conducted on the volume fraction and geometry of conductive minerals.

5. A method, comprising:
placing a wellbore tool in a wellbore to conduct a subsurface assessment of presence of conductive mineralization in hydrocarbon-bearing, mudrock, source rock, carbonate, and sedimentary formations;
making an Electro Magnetic (EM) measurement;
performing at least one of creating an analytical forward model of the EM measurement, creating a numerical finite difference forward model of the EM measurement, performing an inversion;
removing at least one petrophysically-adverse alteration of EM measurements in a frequency range from 1 Hz to 100 MHz; and
wherein the at least one petrophysically-adverse alteration is due to the presence of at least one of the following: pyrite, graphitic-precursors, magnetite, and other conductive minerals.

6. The method according to claim 2 , wherein the EM measurement is made of at least one of disseminated conductive/non-conductive vugs, veins, fractures, lamentations, and thin beds.

7. The method according to claim 1 , wherein the model satisfies the Kronig-Kramers relationship.

8. The method according to claim 5 , wherein the model satisfies the Kronig-Kramers relationship.

Assignees

• Schlumberger Technology Corp

Inventors

• Misra Siddharth
• Rasmus John
• Homan Dean

Classifications

• G01V3/26 Primary

  operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device (with electromagnetic waves G01V3/30) · CPC title

• G01V3/38

  Processing data, e.g. for analysis, for interpretation, for correction · CPC title

• Y02A90/344

  Cross-Sectional Technologies · mapped topic

• G01N27/048 Primary

  for determining moisture content of the material · CPC title

• Y02A90/30

  Assessment of water resources · CPC title