English: Caption: (1) Surface facilities for the freeze wall include access points to the closed-loop pipe system, monitoring wells and groundwater wells, which will pump out the groundwater from the inside the contained reservoir once the freeze wall is built. (2) A chilled liquid would be circulated through a closed system of pipes causing the water in the surrounding rock to freeze and eventually form a wall of ice. This freeze wall will serve as a barrier to keep groundwater out of the contained reservoir. (3) Shell will drill a maximum of 150 holes spaced about 8 feet apart in order to create the closed-loop pipe system. (4) Up to 2,000 feet beneath the surface, the shale layer is a rock formation containing an organic matter (kerogen). It is this organic matter trapped in the rock that results in oil and gas when gradually heated.