CARBON SEQUESTRATION EVALUATION

1 . An apparatus for determining a carbon sequestration characteristic of a geological material, the apparatus comprising:

a sample holder comprising a fluid inlet, an inner chamber, and a fluid outlet, wherein the sample holder is configured to hold a sample representative of the geological material within the inner chamber and to permit a flow of fluid from the fluid inlet through the sample and thence out the fluid outlet;

a pressure pump configured to apply a confining pressure to the inner chamber;

a first pressure gauge and a second pressure gauge configured to measure a fluid pressure at the fluid inlet and a fluid pressure at the fluid outlet, respectively;

a carbon dioxide pump configured to inject carbon dioxide into the inner chamber via the fluid inlet;

a separator for separating a volume of carbon dioxide from fluid flowing from the fluid outlet; and

a return line configured to return at least a portion of the volume of carbon dioxide separated by the separator to the fluid inlet.

2 . The apparatus of claim 1 , further comprising a gas flow meter to measure a flow rate of the gas flowing from the fluid outlet to the separator.

3 . The apparatus of claim 1 , further comprising a treatment injection pump configured to inject a treatment chemical into the fluid inlet.

4 . The apparatus of claim 3 , wherein the treatment chemical comprises an oxidizer.

5 . The apparatus of claim 4 , wherein the oxidizer is water-soluble.

6 . The apparatus of claim 1 , wherein carbon dioxide injected by the carbon dioxide pump comprises a mixture comprising (a) carbon dioxide returned by the return line and (b) carbon dioxide from a carbon dioxide tank.

7 . The apparatus of claim 6 , wherein the carbon dioxide from the carbon dioxide tank has not been in contact with the sample before the injecting.

8 . The apparatus of claim 1 , further comprising a gas chromatograph-mass spectrometer configured to determine a composition of a fluid mixture flowing from the fluid outlet.

9 . A method for evaluating a carbon sequestration characteristic of a geological material, the method comprising:

applying a confining pressure to an inner chamber of a sample holder, wherein a sample representative of the geological material is disposed in the inner chamber;

injecting carbon dioxide into the inner chamber via a fluid inlet of the sample holder, thereby flowing the carbon dioxide at least partially through the sample;

determining a carbon dioxide sequestration characteristic of the sample based, at least in part, on at least one of (a) a change in measured inner chamber pressure or (b) a change over time of a pressure differential across the sample;

flowing, out of the inner chamber via a fluid outlet of the sample holder, a fluid at least partially comprising the carbon dioxide flowed through the sample;

separating a volume of carbon dioxide from the fluid flowing from the fluid outlet; and

re-injecting at least a portion of the volume of carbon dioxide into the inner chamber.

10 . The method of claim 9 , wherein the carbon dioxide sequestration characteristic comprises a volumetric carbon dioxide storage capacity of the sample and wherein said volumetric storage capacity is based at least in part on a measured difference between measured inner chamber pressure before and after injection of the carbon dioxide.

11 . The method of claim 9 , wherein:

the geological formation of which the sample is representative comprises a saline-saturated formation;

the carbon dioxide sequestration characteristic comprises an increase in carbonate mineralization in the sample resulting from treatment of the sample by a treatment chemical; and

the method further comprises:

injecting a saline aqueous fluid into the inner chamber;

injecting the treatment chemical into the inner chamber;

measuring, over time, a pressure differential across the sample; and

determining, based at least in part on variations over time of the pressure differential, the increase in carbonate mineralization.

12 . The method of claim 9 , wherein:

the geological formation of which the sample is representative comprises an organic-rich formation;

the carbon dioxide sequestration characteristic comprises an increase carbon dioxide absorption resulting from treatment of the sample by an oxidizer;

the injecting carbon dioxide into the inner chamber comprises a first injection of carbon dioxide; and

the method further comprises:

determining a pre-treatment volumetric storage capacity based at least in part on a measured difference between measured inner chamber pressure before and after the first injection of the carbon dioxide;

flowing, from the inner chamber, at least a portion of the carbon dioxide from the first injection;

injecting an aliquot of the oxidizer into the inner chamber;

injecting carbon dioxide into the inner chamber as a second injection of carbon dioxide;

determining a post-treatment volumetric storage capacity based at least in part on a measured difference between measured inner chamber pressure before and after the second injection of the carbon dioxide; and

determining, based at least in part on a difference between the pre-treatment storage capacity and the post-treatment storage capacity, the increase in carbon dioxide absorption.

13 . The method of claim 12 , further comprising increasing the organic content of the sample by injecting a hydrocarbon fluid into the inner chamber prior to the first injection of carbon dioxide.

14 . The method of claim 12 , wherein the oxidizer is water-soluble.

15 . The method of claim 9 , a further comprising measuring, with a flow meter, a flow rate of the gas flowing through the sample chamber.

16 . The method claim 9 , wherein injecting carbon dioxide into the inner chamber comprises the reinjecting of the portion of the carbon dioxide separated by the separator.

17 . The method of claim 16 , wherein the portion of the carbon dioxide separated by the separator is injected as a mixture with carbon dioxide from a carbon dioxide tank.

18 . The method of claim 17 , wherein the carbon dioxide from the carbon dioxide tank has not been in contact with the sample before the injecting.

19 . The method of claim 9 , further comprising determining, with a gas chromatograph-mass spectrometer fluidically connected to the inner chamber, a composition of a fluid mixture flowing from the fluid outlet.

20 . The method of claim 9 , wherein the re-injecting the at least a portion of the volume of carbon dioxide into the inner chamber is via a return line fluidically connected to the fluid outlet.

21 . The method of claim 9 , wherein the return line is configured to flow the at least a portion of the volume of carbon dioxide to a pump configured to inject the carbon dioxide into the inner chamber via the fluid inlet.