Use of Tracers in Laboratory and Field Tests of Underground Coal Gasification and Oil Shale Retorting.

摘要

Tracers have recently been suggested for laboratory and field experiments of simulated and actual underground retorting of coal and oil shale. The intended use of laboratory and field retort testing is examined and found to be mainly for estimation of properties of the flow field. The field implementation, data reduction procedure and preliminary results of helium tracer work at Hoe Creek II coal gasification experiment are presented. It was found that the active void volume calculated from the tracer data generally agrees with the consumed coal volume determined from material balances. One and two-dimensional dispersion models predict a highly dispersive system. This review of tracer theory and its usual laboratory application has served to point out its limitations and proper usage. The usage of tracer theory in laboratory and field tests of UCG and oil shale retorting was found to include: generation of information on the flow properties; determination of the total amount of active void volume; determination of the dispersiveness of the injected gas; and analysis of flow channeling and fissuring. At this time lack of knowledge of the flow field needed for interpreting the tracer experiments makes the analysis difficult. In order to understand the tracer data, a theory involving the solution of an inverse problem needs to be developed. (ERA citation 03:054282)