Analysis of alternative push-pull-test-designs for determining in-situ trapping of CO2
2012 (English)Conference paper, Abstract (Refereed)
Modeling results of different single-well push-pull (injection-withdrawal) test designs have been analyzed for theirability to determine residual and dissolution trapping of CO2 in-situ. The modeling aims to improve the design ofa CO2 push-pull test that will be part of the field experiment conducted at the Heletz site, Israel, within the EU FP7MUSTANG project. The injection will take place in a saline formation, where the target layer, an about 10 m thicksandstone layer composed of three layers, is located at a depth of 1600 m. Single-well experiments complementtwo-well injection-monitoring tests in that they offer a way of reducing heterogeneity effects on CO2 transport incomparison to two-well tests. The test scenarios simulated combine thermal, hydraulic and tracer tests in line withthe work by Zhang et al (2011), where the test sequences have three main stages divided into (i) reference tests,(ii) creation of a zone of residual gas saturation and (iii) testing during residual gas saturation conditions. One ofthe main interests is to compare different ways of creating the residual zone, the two principal approaches being topush the mobile CO2 away by injecting CO2 saturated water, thus leaving the residual zone behind or by pumpingthe mobile CO2 back. Implications of the different designs on optimal use of tracers are also analyzed.Inverse modeling with the iTOUGH2/EOS17 and EOS7c simulators is used to analyze the ability of the competingtest designs to accurately determine parameters of main interest during CO2 sequestration, in particular theresidual gas saturation and dissolution. The inverse modeling approach uses results from e.g. sensitivity analysisand uncertainty propagation analysis to make design decisions leading to improvements in the test scenarios,choosing the optimum pumping and injection rates, heating effects, amount of CO2 used, tracer and methodto create the zone of residual CO2 trapping, leading to a test design that will give the least uncertainty in theestimated parameters of interest.
The residual gas saturation and dissolution can be derived from measurable responses in temperature, pressure,mass fraction of CO2 in the aqueous phase or tracer breakthrough curves during the test. Longer testsequences with combination of temperature, pressure and tracer measurements help determining the parametersof interest more accurately. Future studies will incorporate a more detailed description of the system when newin-situ data becomes available.
Reference:Zhang Y., Freifeld B., Finsterle S., Leahy M., Ennis-King J., Paterson L., Dance T. Single-well ExperimentalDesign for Studing Residual Trapping of Supercritical Carbon Dioxide. 2011, International J. of Greenhouse GasControl 5, 88-98.
Place, publisher, year, edition, pages
, Geophysical Research Abstracts, EGU General Assembly 2012, Vol. 14, EGU2012-8443
CO2, test design, push-pull, single-well
Earth and Related Environmental Sciences
Research subject Hydrology
IdentifiersURN: urn:nbn:se:uu:diva-190421OAI: oai:DiVA.org:uu-190421DiVA: diva2:583482
European Geosciences Union (EGU) General Assembly, 2012, 22-27 April, Vienna, Austria
FunderEU, FP7, Seventh Framework Programme, 227286