Shikari, Yusuf A., Manager, Storage Research, Gas Research institute, Chicago, Illinois, U.S.A.
The Gas Research Institute (GRI) is currently involved in the development of concepts aimed at an enhancement of natural gas service to the consumer. In order to maintain the attractiveness of the gas options to industrial consumers, and to reinforce the "value-in-use of natural gas to residential as well as commercial customers, it is essential to develop efficient, economical, and safe means of reducing the -cost-of-service, including that of natural gas storage in underground formations. Specifically, research and development (R and D) is needed to explore ways to better utilize existing storage fields and also to develop new storage facilities at minimum cost.
GRI is currently examining the feasibility of using foam in underground gas storage fields as a mobility control agent to reduce gas migration. Research is also being conducted to establish economic viability of substituting less-costly inert gas(es) for a portion of the base gas, to understand the gas-gas phase mixing behavior in gas storage fields via laboratory experiments and reservoir modeling, and to develop cost-effective gas separation processes using membranes.
This paper provides an overview of the GRI's Gas Storage R and D Program and highlights key results achieved to-date for selected research projects.
The transmission and distribution segments of the gas industry share a common interest in gas storage. To meet peak loads and to ensure dependable delivery of gas to all end-users, gas storage has become a vital link In the supply, transport, and distribution network, of the various forms of natural gas storage technologies being employed to meet different market and application needs, large-scale seasonal storage by utilities in underground formations is perhaps the most prevalent.
The ability to use underground gas storage is now limited by reservoir capacity. One factor that impacts storage capacity greatly is the large proportion of base gas (or cushion gas) required for maintaining a minimum field pressure. Research is needed to optimize the utilization and recovery of base gas and to examine the possibilities of using inert gases as base gas.
Another limiting aspect of underground storage facilities is the migration of natural gas beyond the designated storage volume, primarily during the injection cycle. The migrated gas if often difficult to recover, thereby reducing the volume of recoverable working gas. An effective, economical means of controlling migration in underground gas storage facilities is also needed.
Although there is some regional variation, gas industry storage experts estimate that underground gas storage operation and maintenance (O and M) costs are approximately five percent of the total cost-of-service for pipeline and distribution companies. Research is needed to improve t he efficiency for gas storage operations and reduce these costs. The American Gas Association (A.G.A.) Pipeline Research Committee (PRC), through its Storage Supervisory Committee (SSC), has focused its storage-related R and D program on these near-term needs of the gas industry. In 1987, however, due to funding priorities, the research and cancelled plans to initiate nay new research projects related to gas storage.