Modern recovery scenarios of deep subsea resources located at great distances from shore envision some processing of the recovered product on the sea floor prior to transportation to a floating or onshore facility. Subsea petroleum processing and transportation efforts are anticipated to require energy and power to be transported from a power/energy source that is far from the point of subsea utilization, either at subsea processing facilities or at subsea pumping/compression stations. In the case of subsea petroleum and gas recovery, the preferred consumer energy/power source is electrical. Consumers can be expected to be deployed down hole, in sea floor processing facilities and at primary pumping/compression and booster pumping/compression stations on the sea floor located along the length of the tieback pipeline to the onshore receiving facility. Electrical supply is likely to consist of a step-out transmission line running anti-parallel to the tieback with power delivered to booster pumping/compression stations located as required. The length of the transmission line, various global loading scenarios and varying loading at specific receiving points is a challenge for maintaining power quality and stability at each receiving point, where energy/power is drawn to supply loads.

ABS has built preliminary models of subsea pipeline tiebacks and electrical step outs. Engineers have performed simulations of energization of the step out and have studied step-out electrical transients. Future work will focus on the study of steady state and slow dynamic pipeline flow, power system characteristics and the interaction between the hydraulic and electrical systems refining the models to include more of the hydraulic characteristics and electrical characteristics of the coupled systems to increase the fidelity of the simulation.

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