CO2 geological sequestration potential of the low-rank coals in the southern margin of the Junggar Basin

Abstract

Carbon capture, utilization, and storage (CCUS) is considered one of the most effective measures to achieve net-zero carbon emissions by 2050, and low-rank coal reservoirs are commonly recognized as potential CO₂ storage sites for carbon sequestration. To evaluate the geological CO₂ sequestration potential of the low-rank coal reservoirs in the southern margin of the Junggar Basin, multiple experiments were performed on coal samples from that area, including high-pressure mercury porosimetry, low-temperature N₂ adsorption, overburden porosity and permeability measurements, and high-pressure CH₄ and CO₂ isothermal adsorption measurements. Combined with the geological properties of the potential reservoir, including coal seam development and hydrodynamic characteristics, the areas between Santun River and Sigong River in the Junggar Basin were found to be suitable for CO₂ sequestration. Consequently, the coal-bearing strata from Santun River to Sigong River can be defined as “potentially favorable areas for CO₂ eequetfraiion” To better guide the future field test of CO₂ storage in these areas, three CO₂ sequestration modes were defined: 1) the broad syncline and faulted anticline mode; 2) the monoclinic mode; 3) the syncline and strike-slip fault mode.