Experimental studies of Carbon dioxide Injection for enhanced Oil: Minimum Miscibility Pressure(MMP) determination using Supercritical Extractor Unit.
Author
Khan, Gulraiz
Term
4. term
Education
Publication year
2009
Pages
74
Abstract
This thesis investigates CO2 injection for enhanced oil recovery (EOR) and determines the minimum miscibility pressure (MMP) for crude oil from the Halfdan field in the Danish North Sea. Above a certain pressure (the MMP), CO2 and oil become fully miscible, allowing CO2 to mix with and mobilize the oil more effectively. The MMP depends on the compositions of the oil and injection gas and on reservoir temperature, and may be affected locally by physical dispersion. We conducted nine laboratory experiments using a supercritical extractor unit (SFe-SPE) at high pressure and temperature on cubic and cylindrical chalk core samples at 50, 60, and 70°C. Oil displacement by CO2 injection was analyzed, and the MMP was identified by relating the volume of oil produced to pressure. Oil recovery increased sharply up to about 180 bar, where the maximum extracted volume occurred, indicating an MMP of approximately 180 bar. Visual observations showed that at 180 bar the oil had low viscosity and moved like water (consistent with miscible conditions), whereas below 180 bar CO2 was immiscible and extracted oil samples did not flow. At the same temperature, extraction times of 30, 60, and 90 minutes yielded the same MMP. Recovery ratios for cubic and cylindrical samples ranged from 26% to 55% over 100 to 430 bar. The results were consistent with measurements from a slim-tube apparatus. The porosity of the core samples was 36%, and measured under oil or water saturation it was 39%. The MMP value helps determine whether CO2 injection is applicable to this oil field.
Denne afhandling undersøger CO2-injektion som metode til forbedret olieindvinding (EOR) og bestemmer minimum blandbarhedstryk (MMP) for råolie fra Halfdan-feltet i den danske Nordsø. Når CO2 og olie bliver fuldstændigt blandbare over et bestemt tryk (MMP), kan CO2 blande sig med og mobilisere olien mere effektivt. MMP afhænger af oliens og injektionsgassens kemiske sammensætning samt reservoirtemperaturen, og kan lokalt påvirkes af fysisk dispersion. Vi udførte ni laboratorieforsøg med en superkritisk ekstraktionsenhed (SFe-SPE) ved højt tryk og temperatur på kubiske og cylindriske kerneprøver fra et kalkreservoir ved 50, 60 og 70°C. Fortrængning af olie ved CO2-injektion blev analyseret, og MMP blev bestemt ved at sammenholde udvundet olievolumen med tryk. Olieudvindingen steg kraftigt op til omkring 180 bar, hvor det største udvundne volumen blev observeret; dette indikerer, at MMP er cirka 180 bar. Visuelle observationer viste, at olien ved 180 bar havde lav viskositet og flød som vand (tegn på blandbare betingelser), mens CO2 under 180 bar var ikke-blandbar, og de udtagne olieprøver var ikke bevægelige. Ved samme temperatur gav ekstraktionstider på 30, 60 og 90 minutter samme MMP. Genfindingsgraderne for kubiske og cylindriske prøver lå mellem 26% og 55% i et trykområde fra 100 til 430 bar. Resultaterne var i overensstemmelse med målinger fra et slim tube-apparat. Porøsiteten af kerneprøverne var 36%, og målt ved mætning med olie eller vand var den 39%. MMP-værdien bruges til at vurdere, om CO2-injektion er anvendelig i dette felt.
[This apstract has been rewritten with the help of AI based on the project's original abstract]