Simulation of Oil Transport from Field to Facility
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The world s population is growing and by the year of 2035, the energy demand is expected an increase of 40 % compared to today s level. The oil and gas industry will be a vital part of the energy sector in many years to come, and stands today before a new type of petroleum operations. The Barents Sea region have large amounts of untapped resources, but the harsh weather conditions, cold climate, distant locations and lack of infrastructure raise some great challenges regarding production and transportation in a safe and reliable way.To ensure a stable transportation, long distance multiphase transport of hydrocarbons in pipelines is assumed one of the most reliable and cost effective solutions. The distances are huge, and the understanding of how the flow will behave inside the pipeline is very important prior to realizing such projects. Both fluid dynamics, flow assurance, pipeline design and external influences caused by nature need to be considered and taken into account.The subsea factory is a vital part of the transport system. It will provide the required pressure for the pipeline, and a suitable and well-planned design is important to develop successful projects. This thesis consider a moderate field development in the Barents Sea, which produces oil with some gas. Two subsea factory designs are developed in Aspen HYSYS. One consist of a gas/liquid separator, a 2 MW pump and a small compressor of 500 kW. The second design have replaced the gas/liquid separator with a 3-phase separator, having the opportunity of reducing the water cut before boosting.The subsea factory design is simulated together with different cases established in OLGA. The thesis consider three base cases with different step-out distances reaching from 100 km to 300 km. Several sub cases are simulated to evaluate the effect of a reduced diameter, additional boosting, insulation, electrical heating and water separation. Each case is evaluated on both fluid dynamics and flow assurance.Results show that the possible step-out distance heavily rely on adequate boosting power, to provide a stable flow. With the given subsea factory design, a step-out distance of 200 km is possible, but by installing a second compressor unit this distance could easily be expanded to 300 km and even longer distances. The pipeline will then reach all todays planned developments, with an assumption of the terminal being located in Hammerfest. Due to the small amounts of gas, a multiphase pump should be considered for this development. This will reduce the number of units required and save costs.Hydrates and wax will form in moderate to low amounts. Hydrate inhibitor should therefore be applied, and MEG is the preferred choice. A combination of isolation and electrical heat will reduce the formation of both wax and hydrates, and thereby MEG needed. Separation of water indicate having a good effect on required MEG. The pipeline will be exposed to corrosion, and a protective layer of coating should therefore be applied on the inner pipe wall. Cold flow technology is a promising technology that could reduce the costs related to flow assurance to a minimal level.