Estimating the needed DRA dosage
The DRA effect is affected by many things. The pipeline system, its size and form are important factors in how much improvement one can achieve. The flow rate and the fluid properties are equally important. That is why actual full scale field test must be carried out before DRA performance can be specified. However, reasonably exact estimates can be given based on statistics in most of the cases.
You may find the following graph interesting as an illustrative example. The graph gives you a rough estimate about dosage levels typically needed between two pumping stations. The Low Limit and High Limit are statistically calculated lower and higher limits. This example assumes that the pumps can deliver the initial pressure also with increased volume. The length of the pipe is assumed to be 150km.
As one can see from the picture the needed DRA dosage for a 20% flow increase is typically around 40ppm DRA product. The Exact figures can only be specified after the field tests.
