Development of technologies for the pour point depressant treatment of an annular near-wall layer of oil pumped through a main pipeline

Abstract

The technology of depressant utilization, which essentially depends on the method of its addition to oil, has a substantial impact on the efficiency of the main pipeline. Direct injection of a pour point depressant into the reservoir enables to maintain optimal conditions for oil processing, namely, to cool the oil at an optimal rate and, which is especially important, in static conditions. But in this case, significant capital investments will be required for mixing devices, devices for cooling oil, for the construction of additional tanks, etc. The addition of pour point directly into the pipeline (before or after the head pumping and heating stations) cannot provide optimal cooling conditions. This process does not significantly improve the rheological properties of oil as compared to the introduction of a depressant directly into the reservoir. The introduction of a pour point depressant directly into the pipeline will significantly reduce capital costs for processing highly paraffinic oil and the advantages of this method are obvious. The proposed method of depressant utilization will reduce their consumption, and energy consumption for heating oil. This goal is achieved by the fact that the pour point depressant is not added to the entire volume of highly paraffinic oil pumped through the pipeline, but only to the annular near-wall layer of oil in the pipe, thus creating a low-viscosity near-wall layer of the pumped highly paraffinic oil. This paper presents a scheme for the implementation of the proposed method and formulas for thermal calculations of the pipeline sections considering depressant addition to oil.