Research Into Subsea Pipeline Transportation Technical Program For Offshore Heavy Oil Oilfields

When large scale development of Yuedong heavy oil oilfield of Liaohe Oilfield Company starts, subsea pipeline is required to transport the crude oil. To transport crude oil by pipeline is both convenient and economical. Due to the high viscosity of heavy oil (usually several hundreds to even tens of thousands of mPa?s), the pressure drawdown inside the pipeline is quite high and the pumping equipment is much larger than that in low viscosity crude transportation, which greatly increase the original basic construction investment and maintenance and operation costs. To reduce the friction loss during pipeline transportation of crude oil, the viscosity of the crude oil must be reduced before transportation ( the designed viscosity of the crude at the outlet of the pump is required to be less than 500 mPa?s for most crude oil pipelines).All the countries in the world have been looking for the economical and reliable heavy oil transportation method ever since the beginning of heavy oil production. The relatively common heavy oil transportation methods include heavy oil heating transportation, light oil mixing, and emulsification viscosity reduction. The heavy oil in Yuedong Oilfield has properties such as high viscosity, low freezing point, low wax content, and high gel and asphaltene content. In this paper, reliable technical guarantee for pipeline transportation of Yuedong heavy oil has been provided based on the research into the rheological property of Yuedong crude oil and the technological design and program selection for exporting Yuedong crude oil. In the paper, the following discussions were made:â‘ the rheological property of Yuedong crude oil, including a) rhelogical test of the oil/water emulsion; b) analysis of physical properties of Yuedong crude oil and viscosity reduction test; c) rheological test of crude oil with different watercuts; d) analysis of the test results.â‘¡technological calculation of exporting Yuedong crude oil and program selection: a) light oil mixing transportation technology; b) oil heating transportation technology; c) emulsification viscosity reduction transportation technology.Through the rhelogical test of Yuedong oil, calculation of Yuedong oil export technologies and program selection study as well as comparison of the several technologies, including light oil mixing, oil heating, emulsification viscosity reduction, it can be concluded that oil heating and emulsification viscosity reduction transportation both have their own advantages and both of them are economical and feasible and can be recommended as the subsea pipeline transportation programs for Yuedong heavy oil.