Assessment of the CRIP (Controlled Retracting Injection Point) Process for Underground Coal Gasification: The Rocky Mountain I Test

摘要

Results of the recently completed Rocky Mountain I (RMI) underground coal gasification (UCG) field test have shown that the Controlled Retracting Injection Point (CRIP) process for UCG is capable of producing consistently high quality gas from a single injection well for an extended period of time. The RMI CRIP module was in operation for 93 days and gasified over 10,000 tonnes (11,023 tons) of coal, with an average dry product heating value of 253 kJ/mol (287 Btu/scf). The CRIP process, which utilizes a horizontally drilled injection borehole, has the advantage over vertical well process techniques in that it maintains oxidant injection low in the coal seam for optimal resource recovery, and provides a method for reignition of the coal in a different location when gas quality declines as the maturing reactor begins to interact with inert overburden. This report discusses the results of the RMI CRIP module, compares its performance with the simultaneously operated Extended Linked Well (ELW) module, and explains the behavior of the CRIP reactors with the aid of a model developed for describing UCG reactor dynamics for cases in which oxidant injection remains low in the coal. It is shown that both in terms of fundamental understanding and practical application, the CRIP process for UCG in subbituminous and lower ranking coals has reached a level where the remaining technical uncertainties and risk to commercial development have been largely reduced. 6 refs., 8 figs., 4 tabs. (ERA citation 13:048061)