Depositional Environments, Subsurface Stratigraphy, and Post-Burn Characterization of the Paleocene-Eocene Hanna Formation at the Hanna, Wyoming Underground Coal-Gasification Site: Hanna II Phase 1 Experiment

摘要

During the summer of 1981, the Laramie Energy Technology Center conducted a post-burn coring program at the Hanna II, Phase 1, Underground Coal Gasification site, Hanna, Wyoming. Detailed geologic studies were conducted on the altered and unaltered overburden as well as an analysis of the burn cavity. The overburden consists of about 80 meters of Paleocene-Eocene Hanna formation above the Hanna No. 1 coal bed used in the burn. The overburden contains three basic lithologic units: Unit A consists of very fine-grained sandstones, siltstones, and claystones deposited as a lacustrine delta. Unit A is immediately above the Hanna No. 1 coal. Unit B is above Unit A and consists of carbonaceous shales and mudstones containing isolated lenticular and tabular sandstone bodies deposited in a meandering fluvial system. Unit C is above Unit B and contains coarse-grained sandstones and conglomerates deposited in a braided river system. The Hanna No. 1 coal bed accumulated in a poorly drained swamp that was subject to clastic flooding from an adjacent fluvial system. A reactor cavity 26m x 16m x 15m was formed during the Hanna II, Phase 1 burn and partially filled with rubble and three types of pyrometamorphic rock: paralava, paralava breccia, and buchite. The lithology, thickness, and lateral continuity of Unit A had a definite influence on the success of the experiment as the growth of the reactor cavity was contained completely within the unit. Temperatures up to 1200 exp 0 C were reached during the UCG test. (ERA citation 08:022923)