Application of Digital Simulation Techniques to a Natural Gas Transmission System
Authors: Hall O.P. 
Published: December 2007

This paper was prepared for the 44th Annual Fall Meeting of the of the Society of Petroleum Engineers of AIME, to be held in Denver, Colo., Sept. 28-Oct. 1, 1969. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal, provided agreement to give proper credit is made.
Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
Analytical simulation techniques can be effectively used to predict the performance characteristics of a natural gas transmission system. A satisfactory method for ascertaining the performance determinates of such a system has been obtained through the application of a digital simulator. This paper briefly discusses some of the fundamental concepts behind present continuous system digital simulators present continuous system digital simulators and provides an illustrative example on the use of one for analyzing a natural gas transmission system.

Introduction
Until recently, the problem of determining the operational characteristics of a natural gas transmission system was solved either by steady-state flow considerations or by graphical techniques. With the advent of high-speed digital computers and associated software, it has now become possible to determine more precisely the performance of such a system by precisely the performance of such a system by employing digital simulation. Application of digital simulation techniques provides an avenue for handling both the inherent nonlinearities and time dependency that characterizes a gas transmission system.
This paper will present an overview on the "state-of-the-art" of continuous system simulation languages as they exist today. Here, an emphasis will be placed on giving the reader insight into the operational aspects of evaluating transmission systems with a digital simulator rather than discussing actual coding techniques. In addition, a rigorous mathematical treatment of the fundamental elements that constitute a pipeline complex will be presented along with the programming steps necessary to simulate the developed model. Finally, a short-term [24-hour] simulation problem for a manifold pipeline system is considered. pipeline system is considered. The simulation task is to produce a realistic set of performance parameters [e.g., flow-time histories at the boundaries] so that a comparison can be made with a given set of measured values. The data obtained from this simulation is of practical interest, since the 24-hour time-varying supply and demand for gas represents an actual condition that exists within the natural gas industry today.

CONTINUOUS SYSTEM SIMULATION LANGUAGES
For a number of years a concerted effort has been under way by leading aerospace companies to acquire multipurpose digital simulators. The need for this type of software has become increasingly important in order to evaluate the sophisticated design of today's missile and spacecraft systems.