Two-phase flow, ubiquitous to waterflood oil recovery, geological CO2 storage, and groundwater remediation, is strongly influenced by wettability, and made more complex under mixed-wet conditions. Optimum wettability for such operations is not well established due to limited experimental data and difficulties in their interpretation. This thesis investigates the impact of mixed-wettability, characterised by advancing contact angle θa on capillary pressure, relative permeability, and waterflood displacement. Using a Darcy scale simulator, relative permeability kr, capillary pressure Pc, and residual oil saturation Sor were extracted by history matching production and pressure drop data from centrifuge brine invasion and waterflood displacements completed for a range of θa. As θa increased, a larger |Pc| was required to displace oil from mixed-wet cores at high initial oil saturation. End point oil and brine permeability decreased with increasing θa. A permeability enhancement, such that kr > 1, was measured both when the flowing phase was wetting and non-wetting and was attributed to a slippage at the oil/brine interface directly correlated to θa. Residual oil saturation decreased monotonically with increasing θa while core-averaged remaining oil saturation at the end of the waterflood exhibited a non-monotonic dependence on θa. Simulations of the waterfloods revealed that both significant capillary end effects and premature termination of the waterflood in the laboratory contribute to the deviation between remaining and residual saturations. This work demonstrates that the former is not representative of the latter, as it has been assumed in a number of studies in the literature. Both corefloods and microfluidic waterfloods show the importance of combining experimental studies with simulation for correct interpretation of the measurements especially under capillary dominated flow.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:760032 |
| Date | January 2018 |
| Creators | Christensen, Magali |
| Contributors | Tanino, Yukie ; Pokrajac, Dubravka |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=239075 |
Page generated in 0.0021 seconds