Challenging combination of CO₂ geological storage and coal mining in the Ordos basin, China

Abstract

In a CO 2 storage project, CO 2 may be able to escape from channels caused by the formation's uplift, fault reactivation, and wellbore failure owing to overpressure build-up and likewise, coal excavation during which equilibrium disruption of stress could possibly lead to fl oor heave, roof collapse, and surface subsidence. When the carbon capture and storage (CCS) project and coal mining engineering activity occur in the same location, coal mining may also induce wellbore failure if the stope border is too close to the well. This is a real and challenging problem for CO 2 geological storage in the Ordos Basin in China. We consequently investigated four key problems for such a combination system. The main conclusions obtained from numerical simulations are as follows. (i) Permeability is the most important factor that affects the fl ow rate at the injection point and the reservoir pore pressure. (ii) The interfaces between the coal layers and their adjacent rocks are easy to damage the casing. Our work suggests that the coal pillar should be set aside at least 90 m to maintain the tensile strength of the casing below the designed value. (iii) No impact occurs to the caprock from coal mining; thus, a coal seam 440 m in depth could be excavated if the original caprock is intact and no complex geological structure exists in the location. (iv) Permeability is the most crucial factor affecting surface displacement, and CO 2 injection permits a surface displacement reduction of 0.04136 m compared with individual coal excavation.

Influence of sorption time in CO 2 -ECBM process in Indian coals using coupled numerical simulation

“…However, fossil fuels are highly polluting, as they release huge quantities of CO 2 into the atmosphere. With vast reserves of coal in the world at deep levels, opportunities for geological sequestration of greenhouse gases (GHGs) in these strata are being studied [1][2][3][4][5]. India is one country which is making progress in research on carbon storage in coal [6,7].…”

Impacts of stratum dip angle on CO2 geological storage amount and security

“…It can cope with long‐duration CO 2 geological storage problems, and make up for space and time restrictions experienced by laboratory experiment and field testing. Among such models, TOUGH2, a non‐isothermal multiphase flow simulation software, has been widely used in the United States, Europe, Australia, Japan, and China . A user‐interface computer (visualization) code, TOUGHVISUAL, has been developed for TOUGH2 and TOUGHREACT to deal with the modeling of complex geological conditions .…”

Interaction analysis for CO2 geological storage and underground coal mining in Ordos Basin, China

“…(Li et al, 2009b) a M-S inter-bed: mudstone-sandstone inter-bed. Considering the future prospects for the commercialization of CCS (Li et al, 2014a), i.e., the injection rate is usually at least 1 Mt/year, the pore pressure may also increase significantly. After one year of injection, the pore pressure at the injection well increases from 21 MPa to 27.72 MPa and then to 30.32 MPa and 32.89 MPa after 2 years and 3 years of injection, respectively.…”