Enhanced Method of Estimating Crude Oil Losses in a Unitized Pipeline Supply and Trunk Facilities

Abstract

Most unitized Pipelines in Nigeria are Trunk lines which take crude oil from flow stations to the Terminals. Very few International Oil and Gas Companies own and operate trunk lines in Nigeria. As a result, marginal field owners, independent producers, and some JV partners share the trunk line for the sale of their crude. But because of the use of wide range of non-compliant meters by the injectors into the trunk lines a lot of line losses due to measurement errors are introduced. Another major feature is that trunk lines are exposed to leakages due to sabotage, aged pipeline and valve failures. The issue here is how does the owner of the trunk line back allocate these losses to their respective injectors. The Reverse Mass Balanced Methodology (RMBM) is currently in use having replaced Interim Methodology (IM) in 2017. In RMBM, the crude trunk line losses have been found to be unaccountable and it's proportionate rule for distribution of the losses to the producers are inequitable as the field owners expressed dissatisfaction with unfair deduction from trunk line operators. This study developed a procedure and an algorithm for estimation of crude contributions from each producer at the Terminal and equitable distribution of crude trunk line losses to the producers irrespective of the type of meters, meter factor and leakages and sporadic theft on the trunk lines. This study also identified two alternatives to the RMBM, the use of Artificial Intelligence (AI) and Flow based models. The results showed that flow-based model accounts for both individual and group losses, not accounted for in the RMBM, and allocates and corrects for leak volumes at the point of leak instead of at the terminal. This is a significant improvement from the RMBM.