Caprock integrity for geological CO2 geosequestration

A method comprising:

• providing an injection well into which fluids are injected into a saline aquifer having a geosequestered CO2 plume therein, the saline aquifer located below a caprock and an interface located between the saline aquifer and the caprock, and
• wherein the caprock comprises at least one leakage pathway;
• injecting a plurality of precursor chemicals comprising bifunctional molecules comprising a first functional group for binding to a mineral surface of the caprock and a second functional group for reacting with the CO2 through the injection well and into the saline aquifer;
• depositing the precursor chemicals at or near the interface;
• contacting the precursor chemicals with the geosequestered CO2;
• and
• reacting the CO2 and the precursor chemicals to reinforce the caprock by one or both of mineralization or gelation, thereby forming reinforced caprock and preventing leakage of CO2 from the geosequestered CO2 plume through the at least one leakage pathway.

A system comprising:

• an injection well for accessing a saline aquifer into which fluids are injected into the saline aquifer,
• a reinforced caprock located above the saline aquifer and an interface located between the saline aquifer and the caprock,
• a geosequestered CO2 plume in the saline aquifer beneath the reinforced caprock, wherein a plurality of precursor chemicals are injected through the injection well and into the saline aquifer,
• wherein the precursor chemicals are deposited at or near the interface,
• wherein the reinforced caprock is comprised of one or both of mineralization or gelation by a reaction between the CO2 and the plurality of precursor chemicals produced when the CO2 contacts the plurality of precursor chemicals,
• wherein the plurality of precursor chemicals comprises bifunctional molecules comprising a first functional group for binding to a mineral surface of the caprock and a second functional group for reacting with the CO2.