Model Capabilities for in-Situ Oil Shale Recovery

摘要

The extensive oil shale reserves of the United States are now under development as an energy source. One of the approaches for extracting oil from shale is the so-called modified in-situ retort. The operation of such retorts for maximum yield requires an understanding of oil loss mechanisms so that operating strategies that minimize these losses can be developed. The present modeling capabilities for describing the behavior and yield from a modified in-situ retort are discussed. It is shown how the advances made in describing retort chemistry have greatly increased the predictive capabilities of these models. Two models that have been subject to comparison with laboratory retorts are described. The first is a one-dimensional model that treats the retort as a packed bed reactor, the second is a quasi-two-dimensional examination of block retorting. Both models are capable of predicting retorting rates, off gas composition and oil yield losses to coking and combustion. The block model, for example, describes conditions where local oil yield losses can be as high as 50%. Areas for further model improvement include additional work on describing retort chemistry, such as the steam/char and gas phase combustion reactions. The major need for modeling now is expansion to multi-dimensional simulation. This is necessary if a predictive capability is to be developed for field situations where sweep efficiency losses and gravitational effects become important. (ERA citation 05:033293)