Tight gas

Tight gas is produced from low permeability and low porosity sedimentary reservoirs. The lack of permeability prevents the gas from leaving the rock.

Tight Gas diagram
Diagram: Tight gas

The sedimentary rock that holds the tight gas has been buried, compacted and heated deep within the Earth’s crust.

Under these conditions gas is generated from organic-rich fragments that are spread throughout the host sedimentary rock. The gas can move once it is generated, but not far because of the low permeability. In this way, the tight rock is the source of the gas as well as the reservoir and trap for the gas.