Research on pipeline and flow assurance solutions of oil and gas transportation from Diamond WHP to FPSO Ruby II

Abstract

In offshore production of oil and gas, transporting products by subsea pipeline always has potential risks affecting the efficiency of the transportation process. For the Diamond oilfield, the process of gathering products and transportation is carried out according to a closed scheme in which the exploited products are preliminarily treated. The separated oil is transported to FPSO Ruby - II while the separated gas passed through the air compressor to increase pressure and then used for gaslift production. In fact, the oil produced at the Diamond oilfield has a high paraffin content, which causes difficulties during transportation. Therefore, the study on flow assurance to ensure the transportation of oil and gas from the Diamond oilfield to the FPSO Ruby - II is imperative. This paper presents the results of the research on flow assurance to maintain the safety of the transportation basing on the analysis of field data and the capability of the current subsea pipeline in comparison with the data gained from models carried out with OLGA software. The results show that the rate of wax deposition at normal steady state condition is relatively low. In addition, the thickness of wax deposition build - up is relatively small by simulation results. However, due to low temperature of transported oil which is lower than pour point temperature, a freeze layer will form on the surface of the pipeline. Therefore, regular pigging is considered the most effective way to remove wax.