EOR upscaling - from lab to field

De viktigste elementene for å oppnå suksess med å maksimere utvinning fra felt i produksjon med økt utvinningsmetoder (EOR) er modellering av injektivitet, kunnskap om gjenværende olje, ekstra olje mobilisering med de injiserte væsker, og skalering fra pore skala mekanismer til felt skala. Det overordnede mål er å oppnå pålitelige simuleringsmodeller på feltskala som dekker alle aspekter av strømning og vekselvirkninger mellom injeksjonsvæsker og reservoar fluid. Dette krever detaljert kunnskap om strømningsmekanismer på pore skale (mikrometer), kjerne skala (cm) og videre på simulering skala (10 til 100m). EOR prosesser som involverer kjemiske komponenter adderer kompleksitet til oppskaleringsproblemet. Disse utfordringene må håndteres bedre for å oppnå pålitelige simuleringsresultat og redusere risiko i prognoser av økt utvinningspotensialet. Hovedmålsettingen i dette prosjektet er å utvikle modeller som gir pålitelige prognoser for økt utvinningspotensialet ved EOR metoder.

-The obtained results has been published in peer-reviewed journals (15 papers), but also shared obtained knowledge to both academia and industry by conference presentations (14 papers). Annual workshops has been arranged to present and discuss results to the industry and research community. The PhD students are key part of this project and have generated papers and theses that are public available. The project obtained excellent cooperations with Heriot Watt University (UK) and UNICAMP (Brazil). The industry interest has generated a new Joint Industry Project, that will build on the results obtained in this project.

The key aspects of successful progress in maximizing oil recovery by Enhanced Oil Recovery (EOR) are in modelling of injectivity, knowing remaining oil target in the reservoir, oil mobilization by the injected fluids, and upscale pore scale mechanistic effects to field scale. Ultimately, the overall goal is reliable simulation models at the full field scale, covering all aspects of flow and interactions of any mixture of native and non-native reservoir fluids. This does, however, require thorough understanding of the flow mechanisms at smaller scales, from pore (micrometer) to core (cm) and further to simulation grid cells (tens or hundreds of m). Injectivity of non-Newtonian fluids like polymers is very complex and involves shear thickening near the injection well, and transition to shear thinning behavior further out in the reservoir. In addition, pre-shearing of polymer at the injection site, and non-equilibrium effects near the well influence properties of porous medium rheological properties. Quantifying remaining oil saturation is a challenge. Capillary trapped oil may be reasonably estimated, but the local by-passed (mobile) oil is more uncertain and still very important for EOR oil recovery potential. Upscaling from pore to core and field scale is a challenge even for waterflood in heterogeneous reservoirs. EOR processes involving chemical components add complexity to the upscaling problem. These problems need to be handled better in order to reduce risks in forecasting EOR potential and moving EOR into application for Norwegian oil fields. The strong interest both from oil companies and reservoir simulation service companies for this project is a firm confirmation that the knowledge needs addressed are the key bottlenecks and that the industry will be making use of the results obtained.