Study On Flow Assurance Of Deep Water Pipeline In Angola Oilfield

This thesis studies the flow assurance of deep water pipeline in Angola oilfield, and the water depth is about 1.5km-2.0km. Via investigating the deep water pipeline flow risks and establishing parameter prediction model, research the typical flow assurance issues in Angola.Firstly, through comparing and analyzing different gathering and transportation patterns, combined with actual situations in West Africa, such as deep water environmental conditions, gas and oil properties and so on, choose the suitable pattern ―FPSO+SPS+SHUTTLE‖. With the numerical simulation, calculate the gas lift and multiphase booster pump parameters, like ingection gas volume, pump shaft power, pump pressurization value. Also do the sensitivity analysis of gas lift. The study indicates that the increase of ingection gas volume and watercut helps gas lift’s pressurization, but the increase of gas-oil ratio and throughout cannot. Under the influence of wellhead pressure, liquid producing and watercut, the injection gas volume and pump pressurization value are different from year to year, but generally goes up.Establish the steady simulation model of deep water pipeline system. Study the variation of temperature drop, pressure drop and accumulated liquid volume and influencing factors for different years. Due to the big increase of watercut, the pressure drop of deep water pipeline increases year by year, while the temperature drops decrease. Improve the hydrate prediction model and ensure its accuracy by experimental verification. Based on the basic parameter calculation, predict the hydrate formation and wax deposition in the pipeline and propose corresponding prevention measures. The main work is to design the hydrate inhibitor injection process for deep water oil and gas gathering system, including determining the injection gas volume, injection point and inhibitor regeneration process. Also choose suitable paraffin control paraffin removal technology for Gengibre oilfield.Based on the study of transient multiphase hydraulic and thermodynamic model, establish transient simulation model for target deep water pipelines. Research typical transient processes, including inlet flow mutation, shutdown and restar-up and pigging. Make sure the threats to flow assurance in different transient processes, so that we can make strategies during the design and operating period. The survey shows that the improvement of throughout is conductive to the prevention of hydrate formation and wax deposition. But the inlet flow mutation, shutdown and restar-up and pigging processes can cause pipeline overpressure and overflow of slug catcher. Also throughout changes and diameter variation can make some influence to pipeline’s safe shutdown time. This research is important for the flow assurance of deep water pipeline, making sense to the operation on the spot.