Abstract

A unique black trona water occurs in oil shales of the Wilkins Peak Member of the Green River Formation in the northern part of the Green River Basin, Wyoming. The color of the water is caused by organic acids dissolved in sodium carbonate brine. From 1949 through 1972, 18 wells penetrated the aquifer. Recent drilling has extended the area five miles west, encompassing an estimated area of 20 additional square miles.

Because the black water aquifer was of an unknown type, the Laramie Energy Research Center cored it with a rubber-sleeved core barrel which recovered the core intact. Slow coring and careful measurements pinpointed the aquifer in the subsurface to within a 3-inch length. The aquifer is established as one or two smooth horizontal partings in oil shale rather than cavities created from secondary crystallization. The aquifer is pressurized by overburden rather than gas or hydrostatic pressure.