Oil recovery from carbonate and limestone reservoirs is largely characterised by oil wet and hence improving recovery is dependent on how efficiently one can alter its wettability to water. At UNSW School of Minerals & Energy Resources Engineering, we’ve established nano to micro-scale facilities to improve our understanding wettability alteration of limestone reservoirs.
At nano scale (molecular level), we study adhesion and repulsive forces of oil droplets on calcite surface in presence of different fluids at reservoir conditions by employing molecular dynamic simulation and atomic force microscopy.
At core scale, we carry out multiple phases (oil-water) displacement tests and study both numerically (geo-chemical modelling) and pore-scale micro-CT imaging to map saturation profile and contact angles. Data derived from nano and microscale study are then fed into geochemical modelling.
Ion Tuned water Flooding (ITWF) offers improved extra recovery, lower project cost and minimal environmental impact:
- Improve understanding of oil-water-rock interaction leading to change of wettability to water wet.
- Capability of multi-physics-based upscaling of oil-water-rock interaction and its effect on wettability alteration from relatively small sample to laboratory core scale and then to field scale.
- Prediction of oil production potential by ITWF and quantitative assessment of economic gain.
- Micro- to macroscale characterization and flow simulation in complex limestone and chalks and prediction additional
- Contact angle estimation based on geochemical properties of brines, oil and carbonates, supported by intermolecular forces analysis and measurements
- Development of numerical solution for geochemistry-coupled fluid flow simulation to predict the effect of ion-alteration on oil recovery.
- Assessment of feasibility of ITW applications for other purposes, such as oil pollution remediation in soils.
Following projects have been supported by ONGC and ADNOC:
- Review of existing water flood program for ADCO and develop a plan for low salinity water injection program
- Design low saline sea water injection program for Mumbai High
Facilities & Infrastructure
- Core flooding equipment for experiments on micro plugs at high pressure (up to 2500 psi) conditions
- High pressure, high temperature equipment for rock aging
- Access to measurement surface interacting forces by atomic force microscopy
- Access to μ-CT up to 2 μm resolution for precise imaging of changes in phases
- Access to state-of-the-art image processing software (Avizo, Mango) on high performance computing