Monitoring procedures used in underground gas storage operations are reviewed. Besides bringing together the many techniques now used, methods are presented for systematizing the monitoring process.
The underground storage of natural gas is a relatively young industry. In some 20 years of major growth, storage facilities deliver to market annually some 1.5 trillion cubic feet of natural gas. Major gas systems deliver from storage as much as one-third to one-half of their total send-out on a cold winter day. Further indication of the industry's maturity is the effort to improve safety of operation and control of gas reservoirs. This paper reviews the monitoring procedures of gas storage reservoirs and suggests ways of systematizing the alerting process so that appropriate action can be taken, should any imperfection in the system appear.
The storage operator is expected to know where his inventory of stored gas resides. He is charged with sending to market large quantities of gas in a short period at planned rates of delivery. Monitoring is the taking of observations which will insure the satisfactory operation of the storage facility. The primary concern is that no unknown gas migration underground is taking place. Early detection of unexpected gas movement — penetration of caprock—movement behind the production pipe — or loss from surface equipment — pipe — or loss from surface equipment — can initiate remedies to minimize any effects on the environment.
Monitoring is interpreted as not only sensing the basic information but also transmitting it to the proper decision center for action. People are a vital part of any monitoring system and must be included in its consideration.