Figure 1: Geological setting of the CO2W55 drill hole.
From: Observational evidence confirms modelling of the long-term integrity of CO2-reservoir caprocks
The hole was drilled 90 m north of the Little Grand Wash Fault south of Green River, Utah22,23. It transected the Entrada Formation, the Carmel Formation, a small splay fault related to the Little Grand Wash fault within the Carmel Formation, and entered the Navajo Formation at a depth from surface of 200.11 m. Dissolved CO2 and salinity gradients within fluids sampled from the Navajo Formation indicate that CO2-saturated brines (shaded) migrate (wavy lines) from the fault zones along the base of the aquifers and mix with meteoric groundwaters23. Horizons with similar CO2-charged fluids were encountered in the Entrada and Carmel Formations.
