Estimating Natural Gas Pipeline Friction Parameters

In the design and operation of natural gas pipelines, modeling the pressure-flow relationship is of prime importance. There are certain key parameters which must be known before a simulator will accurately model a given pipeline system. These include length, diameter, and friction factor. The length and diameter can be determined easily. Obtaining friction factors or efficiency parameters is a more difficult problem. The simplest and most frequently used method to determine this parameter is to perform a flow test, measuring the pressures and flows. The measured data are then used in a steady-state equation to compute the friction parameter. The method suggested herein is to use a transient simulator in combination with a least-squares algorithm. The parameters are obtained without attempting to hold the pipeline at steady-state conditions.