Full text loading...
-
Experimental Evidence of Calcite Dissolution and Induced Precipitation during supercritical CO2 Residence
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 76th EAGE Conference and Exhibition 2014, Jun 2014, Volume 2014, p.1 - 5
Abstract
Prior to injecting CO2 in water-saturated carbonate reservoirs, one needs to investigate the effect of the residence of supercritical CO2 (SCCO2) on the rock integrity and overall physical properties.
In this study, a Savonnieres limestone is characterised in terms of its physical properties, pore chemistry and textural features prior and after 2 or 4 hours SCCO2 residence under in situ stress/temperature conditions. More precisely, elastic waves (Vp and Vs) at ultrasonic frequencies, electrical resistivity (Rt), helium porosity-permeability and pore chemistry are measured before and after SCCO2 aging. In addition, X-ray CT monitoring is carried out during the different steps.
While water chemistry highlights an enhanced calcite dissolution related to the duration of SCCO2 residence, a change in the physical properties is observed between the two residence steps. It is shown from the physical properties that (i) the rock building minerals were dissolved after 2 hours; and (ii) the rock overall integrity increases after 4 hours, highlighting a possible re-precipitation phenomenon.