The Rulison project

Rulison Field is a basin-centered gas accumulation with a long production history dating back to the 1960s. The reservoir is made up of fluvial deltaic sandstones and coals in the lower part of the Williams Fork Formation and alluvial plain sandstones in the upper part. Natural fractures significantly enhance the relative permeability to gas. Two multicomponent (9-C) seismic surveys were acquired in Rulison Field (Figure 1). Production is from Cretaceous Mesaverde tight gas sandstones (Figure 2). The pay section spans a 1200-foot thick interval that is overpressured. The reservoirs consist of multiple-stacked lenticular sandstone bodies with matrix permeabilities ranging from 5 to 80 microdarcies. Williams Production Company, operator, is conducting an infill drilling program to reduce well spacing to ten acres.