Determination of Saturation-Capillary Pressure Relations of Crude Oil-Brine Systems to Estimate Oil-Water Interfacial Areas
EMSL Project ID
25712
Abstract
Effects of salinity on oil recovery and residual oil saturation formation during water flooding are of particular interest for the petroleum industry. Empirical observations indicate that residual oil saturation may be reduced and recovery increased significantly by flooding with low salinity water instead of e.g., seawater or brine. However, the pore-level mechanisms of how low salinity flooding improves recovery are very poorly understood. Quality laboratory data are needed to develop the underlying theoretical bases for these observations. In an on-going DOE funded project entitled "Characterization and Alteration of Wettability States of Alaskan Reservoirs to Improve Oil Recovery Efficiency" attempt are made to develop the underlying theoretical bases for these observations. In turn, an improved understanding that can then be used to target and optimize enhanced oil recovery processes for several oil reservoir types.In the mentioned DOE funded project it was found that the specific oil-water interfacial area (IFA), changed considerably with the salinity of flooding water. Interestingly, the change in IFA was inversely related to the measured total entrapped crude oil saturation. The inverse relation indicates that after lower-concentration salinity floods, the remaining immobile oil has a different morphology (smaller ganglia or blobs) than after higher-concentration floods, yielding larger IFA values. The IFA determinations were obtained using a rapid and non-destructive interfacial tracer column experiments. To improve the understanding of the results obtained with this interfacial tracer characterization method, we propose to obtain a set of IFA data based on measured saturation - capillary pressure data. It has been shown by various authors that IFA's can be computed from these data using thermodyamical and geometric models. Examples of such computations were shown by Dobson et al. (2006) using the main drainage and primary imbibition curves of several two-phase systems. Experiments using the EMSL Subsurface Flow and Transport Laboratory's long-column apparatus are proposed to obtain S-P relations for crude oil as shown in the figure above and compute IFA values using various thermodynamic and geometric models. The computed values will then be compared with the original results obtained using interfacial tracer experiments.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-05-25
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator