The caprock overlies the reservoir acting as the main seal preventing CO₂ from escaping.Any oil- or gas-bearing reservoir rock is overlain by an impervious stratum, commonly called a caprock or seal.A caprock is a rock which forms a seal.
Last month, federal scientists said that the company had fallen far behind schedule because a huge rig hired to drill down about 12,000 feet, or more than two miles, on federal land had not been able to pierce surface formations called caprock.
