Method for examining samples of unconsolidated porous media

Patent metadata

Field	Value
Publication number	US-9417177-B2
Application number	US-201214361631-A
Country	US
Kind code	B2
Filing date	Nov 28, 2012
Priority date	Dec 20, 2011
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A sample of an unconsolidated porous medium is frozen and at subzero temperature is placed into contact with a frozen solution of an X-ray contrast agent. Upon the end of saturation of the sample, X-ray computed microtomography of the sample is conducted at subzero temperatures and by means of analyzing the obtained computer tomograhic image, spatial distribution and concentration of ice and/or gas hydrate inclusions, open and closed porosity, pore size distribution, specific surface in the sample are determined.

First claim

The invention claimed is:

1. A method for studying unconsolidated porous media comprising:
preliminary freezing a sample of an unconsolidated porous medium,
providing a contact of the frozen sample of the unconsolidated porous medium and a frozen solution of an X-ray contrast agent at subzero temperatures,
after saturation of the frozen sample with ions of the X-ray contrast agent scanning the frozen sample by X-ray micro Computed Tomography (micro-CT) at subzero temperatures,
analyzing a micro-CT image obtained by the scanning and
determining three-dimensional distribution and concentration of ice and/or gas hydrates inclusions, open and closed porosity, pore size distribution, specific surface area for the sample.

2. The method of claim 1 , wherein the X-ray contrast agent is a water soluble composition containing a chemical element with high level of attenuation of X-ray radiation.

3. The method of claim 2 , wherein the chemical element with high level of attenuation of X-ray radiation is an element with high atomic weight, and the water soluble composition is a salt or an oxide.

4. The method of claim 3 , wherein the element with high atomic weight is a heavy metal selected from group of elements Pb, Ba, Sr, Ra.

5. The method of claim 1 , wherein the contact of the frozen sample of the unconsolidated porous medium with the frozen solution of the X-ray contrast agent is carried out at a temperature below ice/gas hydrates melting in a porous space of the sample.

6. The method of claim 5 , wherein the contact of the frozen sample of the unconsolidated porous medium with the frozen solution of the X-ray contrast agent is carried out at temperatures from −7° C. to −10° C.

7. The method of claim 1 , wherein the frozen sample of the unconsolidated porous medium and the frozen solution of the X-ray contrast agent are preliminary held at temperatures below ice/gas hydrates melting in a porous space till temperature stabilization.

8. The method of claim 7 , wherein the frozen sample of the unconsolidated porous medium and the frozen solution of the X-ray contrast agent are preliminary held at temperatures from −7° C. to −10° C.

9. The method of claim 1 , wherein the X-ray micro Computed Tomography is carried out at a temperature below ice/gas hydrates melting in a porous space of the sample.

10. The method of claim 9 , wherein the X-ray micro Computed Tomography is carried out at temperatures from −7° C. to −10° C.

Assignees

• Schlumberger Technology Corp

Inventors

• Nadeev Alexander Nikolaevich
• Chuvilin Evgeny Mikhailovich
• Popova Olga Vladimirovna

Classifications

• G01N1/42

  Low-temperature sample treatment, e.g. cryofixation · CPC title

• G01N2015/0833

  Pore surface area · CPC title

• G01N2001/1068

  Cooling sample below melting point · CPC title

• G01N15/0227 Primary

  using imaging; using holography · CPC title

• G01N1/28

  Preparing specimens for investigation {including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q}(mounting specimens on microscopic slides G02B21/34; means for supporting the objects or the materials to be analysed in electron microscopes H01J37/20 {; laboratory gas handling apparatus B01L5/00}) · CPC title