Allocation of commingled pipeline oils to ®eld production

This paper presents a case study of using oil ®ngerprinting technology to correctly back allocate commingled pipeline crude to production from six contributing ®elds in an o€shore southeast Asia basin. A large number of oil and pipeline samples were collected over time and analyzed by gas chromatography for their oil ®ngerprints. In this case, production from each ®eld pipeline could easily be distinguished by their whole-oil ®ngerprints that changed little with time. However, oils collected from the commingled pipelines showed signi®cant chromatographic variation with time, indicating production contribution from the di€erent ®elds to the pipelines varied with time. Quantitative results were attained using a proprietary computer program which mathematically calculates relative contributions ( 3%) of oil mixes based on a best-®t least-squares regression of selected chromatographic peak ratios. This allocation method assisted operations to more accurately determine production for each ®eld or a group of ®elds in the basin. The technique, which provides a new approach to supplement and cross-check production metering necessary for de®ning tax liability, has helped save signi®cant tax dollars for ®eld operation units. # 2000 Elsevier Science Ltd. All rights reserved.