The Application of Linear Flow Models to Natural Gas Distribution Systems
Authors: Yingling Arthur E. , Slater George E. , Raphael David L. 
Published: December 2007

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Abstract
The supply and demand situation is no longer stable for those who are engaged in the transmission and distribution of natural gas. The life of new gas contracts with suppliers has diminished and alternative gas supplies are being offered at premium prices. The demand is far in excess of the actual consumption and both supply and demand are being affected by political regulations which severely affect prices. Questions concerning the effect of these supply and demand changes upon a highly interconnected, gas distribution network are difficult to answer due to the complexity of the flow system. Hence, management and engineering are interested in tools which will give them a better understanding of the repercussions due to some stimulus to such a system.
This paper presents an operations research model, the complex linear flow model, which may be applied to a gas distribution network with ease. The model is capable of sorting out the direct and indirect effects of forecasted changes which affect the distribution network or the effects that emergency situations have upon the entire system. The impact of fluctuating supply and demand as well as changes in the physical network can be better understood after the application of this inexpensive model. The theory behind the model is given and the procedure for application is explained. An actual field example plus two impact studies are also given which exemplify the type of information available from the model.

Introduction
As the oil and gas industry has grown, the flow systems within the industry have become more complex. A flow system can be defined as a black box with an input, measured in terms of a homogeneous flow unit, which travels within the black box according to some process and then eventually leaves. The homogeneous flow unit may range from such things as dollars to barrels of oil. Thus, the economy of the industry or of an individual company may be viewed as a flow system as well as the distribution of oil within a pipeline network. Complexity of the flow systems pipeline network. Complexity of the flow systems has arisen because of the high degree of connectivity required in the design of today's flow systems and is also enhanced when an existing system is modified to meet new requirements. Hence, it is difficult to make an analysis of how and to what extent a particular flow system will react, both directly and indirectly, to changes either in the input, the system itself, or the output.