Context
Associated petroleum gas utilisation at a mature onshore oil asset. As the field gassed out, the gas-oil ratio was set to rise roughly 13-fold over field life, and the existing processing facility was already close to capacity.
Role
Study lead on the owner side as Concept Development Manager. Engineering was executed by an external technical centre under my direction; the evaluation criteria, the weighted scoring method and the one-page decision-brief format were my design.
Challenge
Find the true capacity constraint over the full life of field, fix it without building permanent worst-case steel, and decide what to do with the gas, all within an eight-month Pre-FEED that had to align production, facilities and contractor scopes.
Action
- Screened facility loading phase by phase (liquid, oil, water, gas) with a hydraulic throughput model over a 17-year profile: the asset was gas-limited, not liquid-limited.
- Checked equipment adequacy unit by unit: actual against rated flow on every separator, scrubber, flare and multiphase pump.
- Identified the system bottlenecks together with the process engineer and set the engineering direction; proposed most of the practical options, with the contractor adding the unconventional ones.
- Defined three debottlenecking configurations to comparable maturity and screened them on cost and on stability at peak inlet gas-oil ratio.
- Defined the weighted scoring method, trained the engineering centre to apply it and required a one-page technical note per option, so weak options were dropped before deep engineering.
- Screened about 19 gas-use routes, from third-party processing, reinjection and power to GTL, methanol and LNG, down to a realistic shortlist.
- Flagged early that the inlet tie-in needed a facility shutdown, so the work was folded into a planned turnaround.
Result
Compact pre-separation gas takeoff selected: about 3× cheaper than the separator-based options and the only configuration stable at peak gas-oil ratio. The gas peak lasts about five years, so capacity was phased instead of sized for permanent worst case, and the short plateau ruled out gas chemistry as the wrong scale of solution. Pre-FEED delivered for the $160M project as the basis for concept selection and investment readiness.
