Prediction of Rubble Characteristics and Flow Fields Through a Porous Medium Using Gaseous Tracers: A Feasibility Experiment

摘要

Results from an extensive series of tracer tests are presented. Nonradioactive tracer gases were injected into a large experimental retort at Laramie, Wyoming. The retort was filled with crushed and screened raw oil shale from the Anvil Points mine. The resulting data were used to study the feasibility of the use of gaseous tracers to characterize modified in situ (MIS) oil shale retorts. The effect of an impermeable cylindrical obstruction within the rubble on the resulting tracer signals was quantified. In addition to the tracer tests, thermal data were obtained from a steam front passed through the retort by the steady-flow addition of a 30 volume percent steam/air mixture. The resulting temperature profile was uniform, indicating a negligible effect of the zero-permeability region on steam sweep efficiency. The tracer signals, however, were slightly affected by the presence of the non-uniformity. In addition, wall effects and local regions of less pronounced non-uniformities were apparent from the tracer responses, but not from the thermal data. This experiment has demonstrated that tracers are effective in determining the existence of permeability contrasts. Further testing on a similar retort, but with a more significant discontinuity (one which would reduce the steam sweep efficiency) is recommended to verify the characterization ability of tracers. This report includes all the data in graphical form as well as a complete summary of the analysis. It constitutes a data base which could be used in future model development and verification of both forward and inverse solutions. (ERA citation 09:019700)