This case study targets the elimination of routine flaring of associated gas from Libya's offshore Bouri field, where CO2 reaches 44% and N2 reaches 12%, a composition that previously prevented utilization and stalled an acid-gas re-injection concept on platform weight and safety grounds.

An integrated offshore and onshore scheme was developed and modelled in Aspen HYSYS (Peng–Robinson EOS). To respect platform weight limits, offshore treatment was minimized to compression, solid-desiccant dehydration, and membrane separation conditioning only the fuel gas stream. Membrane treatment reduced CO2 from 44.8% to 18.4%, yielding 12.5 MMSCFD of fuel gas that fully supplied platform turbines, with the CO2-rich permeate (≈82%) recycled to compression.

The remaining ≈120 MMSCFD was exported for onshore blending; four ratios were evaluated against export specifications. CO2 met the <2 vol% limit in all cases, while N2, rather than not CO2, emerged as the binding operational constraint at low blend ratios (10.5 vs. <10 vol%).

Recovered CO2 is allocated to enhanced oil recovery (CCUS), with an estimated ~3.1-year payback. Key lessons learned address N2-driven specification compliance, sweetening-solvent limitations at ~20% CO2 feed, and weight-driven offshore design trade-offs.