Patent ID: 11959364
Assignee: TERRAH2 LLC
Field: Civil engineering (Other fields)
Classification: CPC C  E  B  Y | IPC B  E

Claim 0:
1. A method of storing and recovering hydrogen gas in a kerogen-rich unconventional gas reservoir, the method comprising:
a. injecting a fracturing fluid through a horizontal wellbore into the gas reservoir to cause fracturing within the gas reservoir;
b. recovering a methane-containing gas through the wellbore;
c. projecting an H2 molar fraction χ(H2)RES(TRES) of a hydrogen-containing gas recovered from the gas reservoir at each of a plurality of corresponding reservoir pressures PRESSURERES(TRES) at respective reservoir times TRES, the projecting including:
i. sampling a hydrogen-containing gas recovered from a gas-reservoir core sample held in the core-sample holder, to determine a plurality of core-sample value-pairs for respective core-sample times TCS, each core-sample value-pair including an H2 molar fraction value χ(H2)CS(TCS) and a respective core-sample pressure value PRESSURECS(TCS), and
ii. matching PRESSURERES(TRES) values with respective PRESSURECS(TCS) values of the plurality of core-sample value-pairs to project χ(H2)RES(TRES) values based on respective χ(H2)CS(TCS) values corresponding to the matched respective PRESSURECS(TCS) values;

d. responsively to and contingent upon reaching a hydrogen-purity trigger criterion based upon said projecting of H2 molar fraction values χ(H2)RES(TRES), injecting hydrogen gas through the wellbore into the gas reservoir at a shut-in gas pressure at a wellhead; and
e. recovering, through the wellbore, a hydrogen-containing gas having an H2 molar fraction equal to or greater than the hydrogen-purity trigger criterion.