Drilling and sampling a natural CO2 reservoir: Implications for fluid flow and CO2-fluid–rock reactions during CO2 migration through the overburden

Abstract

23This paper presents the initial results of a scientific drilling project to recover core 24 and pressurized fluid samples from a natural CO 2 reservoir, near the town of Green River, 25Utah. The drilling targeted a stacked sequence of CO 2 -charged Jurassic sandstone reservoirs 26 and caprocks, situated adjacent to a CO 2 -degassing normal fault. This site has actively 27 leaked CO 2 from deep supercritical CO 2 reservoirs at depth >2km within the basin for over 28 Geyser constrain mixing models which show that, within the Navajo Sandstone, the 49 reservoir fluids are undergoing complex mixing of: (i) CO 2 -saturated brine inflowing from 50 the fault, (ii) CO 2 -undersaturated meteoric groundwater flowing through the reservoir and 51 (iii) reacted CO 2 -charged brines flow through fracture zones in the overlying Carmel 52Formation caprock, into the formations above. Such multi-scale mixing processes may 53 significantly improve the efficiency with which groundwaters dissolve the migrating CO 2 .

Evolution of fault permeability during episodic fluid circulation: Evidence for the effects of fluid–rock interactions from travertine studies (Utah–USA)

“…The leakage of CO 2 along faults has been identified and documented in previous studies showing a spatio-temporal migration of CO 2 -enriched fluid leakage zones along the faults (Burnside et al, 2013;Dockrill, 2005;Dockrill and Shipton, 2010;Kampman et al, 2012;Shipton et al, 2004). This leakage has been evidenced to start at least 400 ka ago and the U-Th dating of aragonite veins indicates that the recorded CO 2 pulses can be related to glacial cycles (Kampman et al, 2014). However important questions remain to be addressed: i.e.…”

“…O changes at vein scale indicates kinetically-driven vein precipitation (Kampman et al, 2014;Kele et al, 2011). In addition, veins' enrichment with heavier δ 13 C compared to the stable carbon isotopic composition of the present day Crystal Geyser water may be due to rapid CO 2 degassing (Fouke, 2011;Fouke et al, 2000).…”

Scientific drilling and downhole fluid sampling of a natural CO<sub>2</sub> reservoir, Green River, Utah

“…In this contribution we focus on the drilling operation itself and the sample recovery, and provide a brief description of the fluid sampling results. Details of the study of the core-samples and fluid geochemistry are ongoing; the initial results are presented in Kampman et al (2013b), and detailed analyses of the reservoir and cap rock core-samples will be presented in future publications.…”

CO2 Leakage-Induced Contamination in Shallow Potable Aquifer and Associated Health Risk Assessment

“…As an example, Kampman et al [54] analyzed the mineralogical assemblage of Navajo Sandstone, which was considered to be the primary sourcing aquifer for CO 2 -charged brine [55]. Chemical analyses of Navajo Sandstone fluids collected either from adjacent geysers or from springs revealed elevated concentrations of both arsenic and other toxic heavy metals [54,[56][57][58].…”