A layer of rocks that do not allow liquids or gases flow through the rock layers, not allowing liquids or gases flow through. Cover the top layer of stone blocks and the catchment of the petroleum, hydrocarbon escape to the surface of soil. [PI growing petroleum products]
A layer of rocks that do not allow fluid or gas flow, the rock did not allow the fluid or gas flow. Cover the top of the shale reservoir. And blocking the escape of hydrocarbons to the surface soil. [Petroleum]
A layer of stone not liquid or gas flow,, I rock let liquid or gas flow. Seal at the top of the rock, petroleum storage Block hydrocarbon and escape to the soil surface. [petroleum].