Interactions With Acid Gas

Tests will be conducted to ensure the acid gas is compatible with the reservoir rock and reservoir fluids. Adverse reactions could reduce injectivity with time, as the acid gas reacts with the formation rocks or the original fluid in the reservoir. 

As was noted earlier, mineralization of the acid gas components is not necessarily a bad thing. On the contrary, it may be an excellent mechanism to sequester the acid gas safely and permanently. 

It is only a problem if the resulting reaction plugs the formation, particularly in the near-wellbore region and thus inhibits the injection process. 

The selection of an injection zone is probably the first stage in the design of an injection project. Without an acceptable reservoir, acid gas injection is not feasible. The selected zone must contain the injected fluid - the acid gas must not leak through the caprock, or via other wells that penetrate the zone. Furthermore, injection must be achieved without an excess injection pressure. Fracturing the reservoir may aid injection, but it probably should be avoided because of containment issues. 

Hawkins. 1959. Applied Petroleum Reservoir Engineering. Englewood Cliffs, NJ Prentice-Hall. 

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