The transportation of crude oil with high wax content through a submarine pipeline built without thermal insulation can cause serious problems,. The heat loss due to the sharp temperature gradient between the crude and the environment results in the crystallization of wax in the crude, with a subsequent wax deposition on the walls of the pipeline. This acn result in: 1) reduction of the actual pipeline diameter resulting in higher pressure drops; and, 2) the formation of gelled interlocking structures of wax crystals in the pipeline, leading to shutdowns. The safe and continuous operation of the pipeline has been dependent on the improvement in the flowability characteristics of the Vietsovpetro crude oils. Using your point depressant chemicals can drastically reduce the potential risk for wax deposition and gelling. A study on the rheological properties of the crude oil enables an evaluation of different chemical types necessary to treat the crude. The pressure drop required to start pumping crude oil through newly constructed submarine pipelines or to restart the flow after an emergency production shutdown has to be determined. A pipeline model used to predict the restart pressures and flow characteristics has played a very important role in the technological concept and design of the product gathering system at Vietsovpetro oil fields.