Separation and Re-Injection of CO2 in Enhanced Oil Recovery Processes
Author
Marinov, Ognyan Olegov
Term
4. term
Education
Publication year
2015
Submitted on
2015-01-07
Pages
45
Abstract
This thesis examines the separation and re-injection of CO2 in CO2-based Enhanced Oil Recovery (EOR) for a small heavy-oil field. After about nine years of waterflooding, roughly 22% of the original oil in place had been produced, and the field development was planned as continuous, miscible CO2 injection at an estimated 263,000 kg/d over approximately 18 years. To capture changing production conditions, the period was divided into three five-year stages, and the produced stream composition was estimated from initial and post-waterflood conditions. The core focus is handling produced CO2: separating it from the gas stream and recycling it via re-injection. Two separation methods were evaluated by process simulation in Aspen Hysys V7.3: conventional amine gas sweetening and an ionic liquid–based approach. The amine process delivered very good CO2 removal across all three production stages, enabling effective recycling. Simulations with ionic liquids were unsatisfactory, primarily because the required components and properties are not available in Hysys, limiting model fidelity rather than necessarily the technology’s inherent potential. The thesis also reviews CO2-EOR principles (miscible/immiscible displacement) and implementation barriers. Overall, the case study indicates that established amine-based separation is a robust choice for CO2 reuse in this context, while ionic liquids need better data and model support for a fair assessment.
Denne afhandling undersøger separation og reinjektion af CO2 i forbindelse med CO2-baseret Enhanced Oil Recovery (EOR) for et lille tungolie-felt. Efter ca. 9 års vandfødning var omkring 22% af den oprindelige olie i stedet produceret, og feltets videre udvikling blev planlagt som kontinuerlig, blandbar CO2-injektion med en estimeret injektionsmængde på 263.000 kg/d over cirka 18 år. For at belyse variationer i produktionen blev perioden opdelt i tre stadier à fem år, og produktionsstrømmens sammensætning blev estimeret ud fra initial- og post-vandfødningstilstande. Hovedfokus er på håndtering af den producerede CO2: separation fra gasstrømmen og genbrug via reinjektion. To separationsmetoder blev evalueret ved processimulering i Aspen Hysys V7.3: konventionel amin-gasskrubning og en tilgang baseret på ioniske væsker. Aminprocessen gav meget gode resultater for CO2-fjernelse i alle tre produktionsstadier og understøttede dermed lukket kredsløb med reinjektion. Simulationer med ioniske væsker var utilfredsstillende, primært fordi de nødvendige komponentdata og egenskaber ikke findes i Hysys’ database, hvilket begrænser modelkvaliteten snarere end nødvendigvis teknologens iboende potentiale. Afhandlingen gennemgår desuden CO2-EOR-principper (blandbar/ublandbar fortrængning) samt implementeringsbarrierer. Samlet peger case-studiet på, at etableret aminbaseret separation er et robust valg til CO2-genanvendelse i denne kontekst, mens ioniske væsker kræver bedre datagrundlag og modelsupport for en retvisende vurdering.
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