In accordance with one or more embodiments of the present disclosure, a method of subsurface sequestration of CO.sub.2 in a geological basin includes identifying one or more subsurface sequestration locations in the geological basin and injecting an aqueous CO.sub.2 solution to be sequestered into the geological basin. The one or more subsurface sequestration locations are regions of deeper geological structure, relative to an adjacent shallower geological structure, into which a negatively buoyant fluid injected into the basin will sink. The aqueous CO.sub.2 solution comprises a density that is greater than the density of the water naturally present in the geological basin, such that the injected aqueous CO.sub.2 solution pools in the one or more subsurface sequestration locations.

Provided herein are new methods for assessing carbon dioxide rock volatile contents of subterranean sites to identify changes in the carbon dioxide content of sites, such an assessment then applied to the evaluation of such sites for possible use as carbon capture and sequestration (CCS) sites, carbon capture, utilization, and sequestration (CCUS) sites, and for other applications. Further provided herein are methods for identifying geological features which may compromise a site's ability to serve as a CCS/CCUS site, whereby the methods comprise the application of rock volatiles analysis, mechanical strength analysis, or both, and the subsequent identification of such geological features based on shifts, changes, or patterns in data resulting from the analysis. Additional related methods and systems are also disclosed.

A method for managing a sequestration fluid including sequestering a fluid in a subsurface formation downhole of a caprock and downhole of a seal in a borehole, targeting a sample of formation fluid in the borehole uphole of the caprock and uphole of the seal in the borehole. A sequestration system including a borehole in a formation, the borehole extending downhole of a caprock, a string disposed in the borehole, a seal between the string and a wall of the borehole uphole of the caprock, and a port in the string uphole of the seal and the caprock, the port having access to a portion of the formation uphole of the caprock.

A flow control valve configured to be positioned in a tubing in a borehole formed in a subsurface formation, wherein the flow control is used to regulate a flow of an injection fluid into the subsurface formation based on a vapor-transition characteristic of a fluid contained within a chamber of the flow control valve.

The application discloses an integrated method and structure for in-situ hydrogen production from coal seams and coalbed methane exploitation, belonging to the technical field of energy exploitation. The method comprises: injecting gasification agent through an injection well, exploiting coalbed methane and gasification gas through a production well. The injection well is a stepped horizontal well, the injection well is provided with at least one, and the projections of the horizontal sections of any two injection wells in the vertical direction do not overlap. At least one horizontal section of the stepped horizontal well is arranged in any coal seam to be mined. The method of the present application avoids the large-area continuous gasification of a single coal seam and the repeated position gasification of overlapping multiple coal seams, reduces the change range and degree of formation stress, disperses the underground void volume, reduces the risk of formation or ground collapse.

A carbon dioxide (CO.sub.2) sequestration sensor system includes an underground sub-assembly including one or more sensors configured to detect at least one attribute associated with CO.sub.2 sequestration below a terranean surface; and an above-ground sub-assembly positionable on the terranean surface proximate the underground sub-assembly and including at least one controller communicably coupled to the one or more sensors.

This disclosure relates to membrane-based systems for transporting dissolved gases to a formation and methods for increasing a mass transfer rate of gases in a formation. The membrane-based system may include an aqueous injection well, a diffusion-based membrane, a gas, and an aqueous solution.

A cement composition including a hydraulic cement material, a latent-hydraulic cement material, and a non-hydraulic cement material. Also provided is a method including combining, at a jobsite, the cement composition comprising the hydraulic cement material, the latent-hydraulic cement material, and the non-hydraulic cement material with water to provide a cement slurry, and allowing the cement slurry to harden in the presence of carbon dioxide (CO.sub.2) to provide a hardened cement.

Systems and methods of greenhouse gas removal and subsea sequestration are described herein. Disclosed systems and methods include a direct air capture device capturing greenhouse gases from the atmosphere, a transport apparatus fluidly connected to the at least one direct air capture device, an underwater disposal well fluidly connected to the transport apparatus, and an underwater work apparatus operatively connected to the underwater disposal well. The transport apparatus transfers the greenhouse gases to the underwater disposal well, and the underwater disposal well injects the greenhouse gases into an underwater geologic formation. The greenhouse gases may be solidified as mineral deposits and permanently stored in the underwater geologic formation. Disclosed systems may include a loading system configured to be periodically connected to the transport apparatus. The loading system has a plurality of rotatable joint modules connected by independently actuatable joints.

This disclosure relates to a method and a system for sequestering carbon-containing materials in underground wells. An example method includes: obtaining a material comprising a carbon-containing liquid; optionally testing the material for compatibility with an underground well; optionally adjusting a property of the material to improve the compatibility; and providing the material for injection into the underground well.