Box experiments on monitoring the CO2 migration in a homogeneous medium using electrical resistivity survey

Abstract

Geological sequestration of CO 2 necessarily involves reliable techniques for monitoring the migration of CO 2 injected in deep formations. In this study, a series of lab-scale experiments was conducted to investigate the feasibility of geochemical sampling and electrical resistivity survey in imaging and characterizing various phases of CO 2 in a homogeneous medium. An acryl box packed with 1-mm dia. glass beads was used as the brine aquifer for CO 2 sequestration. Two phases of CO 2 and a supercritical CO 2 substitute were applied in a series of injection processes in modified experiments for simulating CO 2 sequestration. As well as porewater analysis, time-lapse electrical resistivity survey was performed with electrodes positioned on the box. For reconstructing two-dimensional resistivity images, electrical potential differences were measured at potential dipoles on the top surface of the box. To investigate the spatial and temporal evolution of the plume of injecting fluids, 2D resultant resistivity images at specified time were compared with discrete distributions of CO 2 concentration in the box. In the experiment of CO 2 gas, the time-lapse resistivity images showed the distinct increase in resistivity and suggested that the sequential changes in electrical resistivity images could be acquired when the CO 2 gas plume migrates in deep brine aquifers. In the experiment of supercritical CO 2 substitute, the time-lapse resistivity images showed that injected KF−50 was kept afloat by buoyancy, which accumulated under the impermeable layer in free phase, and leaked somewhat to the surface. The electrical resistivity survey can be successfully detect the heterogeneous and localized distributions of supercritical CO 2 in deep brine aquifers, implying that the electrical resistivity tomography could be a useful technical option for monitoring CO 2 during geological sequestration.

Magnetotelluric and temperature monitoring after the 2011 sub-Plinian eruptions of Shinmoe-dake volcano

“…One possibility is that an increased supply of volatiles induced a widening of fractures in the low-permeability seal in this area, resulting in a depletion of shallow low-temperature groundwater. Alternatively, an increase in gas bubbles within the groundwater in this area may have caused a significant increase in bulk resistivity (Wang et al, 2010).…”

An Experimental Study of the Effect of Rock/Fluid Interaction on Resistivity Logs during CO<sub>2</sub> Sequestration in Carbonate Rocks

“…Adebayo, M. Mahmoud 2 ture and sequestration (CCS) must be at this depth (Benson, 2008). While CO 2 is injected into a subsurface formation, four major trapping mechanisms ensue namely: 1) Physical/Structural trapping-a process whereby impermeable cap rock at the top of the formation prevent the CO 2 from escaping out of the formation, keeping it in place (Benson, 2008;Wang, 2010), 2) Solubility trapping-a process whereby injected CO 2 dissolves in formation pore water, 3) Mineral trapping-occurs when aqueous CO 2 reacts with formation rock minerals producing precipitates of carbonate minerals, and 4) Residual or Capillary trapping which occurs after CO 2 injection stops and water begins to imbibe into the aquifer displacing the CO 2 already in the aquifer. Not all the CO 2 is displaced but some are left behind as residual CO 2 (residual trapping).…”

“…With the use of Archie's equation or modified Archie's equation, CO 2 saturation distribution, migration, and volume can be estimated. Many experimental and field studies have successfully used resistivity measurements to monitor CO 2 migration (Ramirez, 2003;Wang, 2010;Giese, 2009;Christensen, 2006;Nakatsuka, 2010). Archie's equation is given in Equation (1).…”

Challenges of Resistivity Log As A Monitoring Technique During Carbon Dioxide Sequestration In Carbonate Formations

“…Potential geological formations according to the Intergovernmental Panel on Climate Change (IPCC 2005) are depleted hydrocarbon reservoirs, un-depleted hydrocarbon reservoirs (during enhanced oil recovery), saline water saturated aquifers, un-mineable coal seams and cavities (IPCC 2005). Depleted oil or gas reservoirs on the other hand are known to have high seal/cap rock integrity but they are also limited by scarce geographical distribution (Wang et al 2010). Geological (Sedimentary) formations are good candidates because: they can provide the pore volumes needed to store large amount of CO2; they have adequate permeability required for efficient injection; and they andare widely distributed geographically (Bachu 2003).…”

“…(Ramirez et al 2003;Christensen et al 2006;Giese et al 2009;Nakatsuka et al 2010;and Wang et al 2010). Many experimental and field studies have successfully used resistivity measurements to monitor CO2 migration e.g.…”