| dc.description.abstract | Greenhouse gases make our planet warmer by trapping heat. The increase in greenhouse gases in the atmosphere has been dramatic since the industrial revolution which is caused by human activities. The Paris agreement created a global framework to limit the average global temperature rise. This can be achieved by considerable reduction in greenhouse gas emissions across all sectors. The key step in emission reduction is transformation from fossil-based energy systems to efficient and renewable-based low-carbon energy systems.
In recent years, electrification of offshore oil & gas platforms, which replaces fossil-based power generation (e.g., gas turbine) with renewable energy, has been in progress in the North Sea. However, there are some challenges that make it difficult to fully electrify all oil & gas platforms. The production fluid composition can be one of the main challenges.
With this regard, the present work investigates the effect of production fluid composition and products’ specification on the electrification of offshore oil and gas platforms. A hypothetical processing plant is modeled in UniSim™ Design R480, which is a process simulation software. Two different reservoir fluids with small and high fractions of C3-C5 components (3,5 and 14 mol% respectively) are used. Feeds with different production rates from each reservoir are applied in the case studies to analyze the effect of the feed’s C3-C5 fraction on the total power consumption.
According to the results, increase in the production fluid’s C3-C5 fraction, makes electrification less favorable and economically justifiable. A higher C3-C5 fraction leads to higher power consumption when the plant is electrified. It is found that the rise in power consumption is small for low C3-C5 fraction production fluids which makes them suitable for electrification. On the other hand, electrification may not be possible for production fluids with high C3-C5 fractions (ca more than 13 mol%) without continuous flaring of the excess C3-C5 or sacrificing some of the products’ specifications.
The product specification dictates its approximate composition, especially the fraction of middle components (C3-C5 components). If the amount of C3-C5 components entering the plant is higher than those leaving the plant, accumulation occurs which can affect the production rate, energy consumption, emission levels, safety, and profitability of the plant.
Optimization of gas processing systems can be a cost-effective approach for the reduction of total power consumption in the transition to electrification or for the cases which electrification is not economical or feasible. One example is to optimize the compressor’s suction temperatures which is investigated with a case study in the current work. According to the results, temperature variation in the suction of re-compressors may have a negligible effect on total power consumption for cases with low C3-C5 fractions in the production fluid. In contrast, cases with high C3-C5 fractions experience high variation in total power consumption. For these cases, there are optimal values where the total power consumption is minimum. | |