When the oilfield development entered the later stage, the throughput of some existed pipelines was lower than the minimum throughput pipeline. The terminalstation the temperature of the oil was lower than the oil condensation point, which could not meet the requirements of pipeline transportation. The appropriate PPD could be chose to reduce oil condensation point, which need not build new heatingstation and effectively cut the transportation costs. Usually experimental method was adopted to select the PPD and determine the injection quantity. The results show that adding the CN16H91 pour point depressant that its mass fraction was 50 μg/g could make the solidifying point of the mixed oil fall from 15.0 ℃ fell to 4.0 ℃, it was lower than the inlet temperature to meet the requirements for pipeline transportation.

In order to ensure pipeline commissioning safety and avoid security risks because of the direct contact between the air and oil, a progress of water isolation was necessary. And how to determine the amount of optimal isolation medium is becoming a new subject. The factors affecting the isolation medium quantity from the point of commissioning process was analyzed and a model to calculate the amount of isolation medium and the mixed oil quantity in a long slope pipeline was built while commissioning, based on existing empirical models, combined with field data. The relative error was in the acceptable range.