Acid Gas Injection
There currently exist several large natural
gas field that contain so much hydrogen sulfide and carbon dioxide that monetization of these assets is currently uneconomical. With increasing demand for new natural gas resources, new ways of dealing with sulfur
and carbon dioxide are being explored and implemented.
Sour Gas
Natural gas that contains hydrogen sulfide
(H2S) in any amount is termed sour gas. Sour gas has an unpleasant odor and is
a hazard to human health and is corrosive to carbon steel when water is present.
Sour gas is sweetened by removing
the hydrogen sulfide with a variety of processes, most of which involve regenerative solvent processes. This technology is well established within traditional limits of hydrogen sulfide. The specific choice of solvent depends on the amount of hydrogen sulfide, carbon dioxide and condensable
hydrocarbons in the sour gas. The most common processes involve the circulation
of amines, which dissolve hydrogen sulfide and carbon dioxide into the amine solution.
The hydrogen sulfide and carbon dioxide are released from the amine solution when the solution is heated. The resulting gas is known as acid gas, and contains a high percentage of hydrogen sulfide and carbon dioxide.
The hydrogen sulfide component of acid
gas has fuel value, and can be burned, creating sulfur dioxide as a combustion product.
Increasingly stringent regulations limiting the emission of sulfur dioxide are eliminating direct flaring or combustion
of acid gas. Sulfur recovery technology that converts the hydrogen sulfide into
elemental sulfur is well known and utilized broadly, however, elemental sulfur is becoming increasingly more difficult to
sell or give away.
Gas Storage
Storage of natural gas into depleted reservoirs
for peak shaving and strategic storage has been done for several decades.
Disposal Acid Gas Injection
In Western Canada, several operators are injecting acid gas into brine aquifers or other technically
appropriate formations.
Pressure Maintenance Acid Gas Injection
In Kazakhstan, operators have begun to inject acid gas into the producing reservoirs.
