Inspectional and dimensional analyses for scaling of low salinity waterflooding (LSWF): From core to field scale

摘要

In the past decade, Low Salinity Waterflooding (LSWF) has gained increased attention as an Enhanced Oil Recovery (EOR) approach. Given a large number of influential parameters, the present study aimed at finding independent scaling groups for LSWF using both Dimensional (DA) and Inspectional Analyses (IA). Scaling was performed using a 2-D vertical reservoir model with homogeneous and anisotmpic permeability. DA was applied using Buckingham Pi theorem resulting in twelve dimensionless groups. In IA, using the governing equations and non-dimensionalization procedure, it turned out that twelve scaling groups are required to reach the similarity of recovery curves in two different scales (i.e. core and field scales). The resultant scaling groups based on both methods were then compared. To further verify these scaling groups, recovery curves of three scenarios with different parameters and the same scaling groups were also compared. Several sensitivity analyses were also performed to discern the impact of each newly developed scaling group to change the breakthrough recovery factor (BRF). Through the sensitivity analysis, one scaling group was proved to be redundant in changing BRF, whereas one was repetitive. Therefore, it was found that ten scaling groups were sufficient for scaling LSWF from core to field scale. The results showed that deviation of the system from Vertical Equilibrium (VE) and scaling groups related to mobility ratio, capillary forces and gravity segregation dominate the total sweep efficiency (i.e. vertical sweep efficiency) of LSWF.